THE 


AMERICAN NATURALIST 


A MONTHLY JOURNAL 
DEVOTED TO THE ADVANCEMENT OF THE BIOLOGICAL SCIENCES 


WITH SPECIAL REFERENCE TO THE FACTORS OF EVOLUTION 


VOLUME XLII 


wwo. Bot. Garden 
1909 


NEW YORK 
THE SCIENCE PRESS 
1908 


„30% ka 


% 


2 
YOL. XLII, NO. 493 


JOHN T. 


ERRATA 


Tue ‘‘Ichthyological Notes’? in the December issue of THE 
American NATURALIST (vol. 41) contain the following errata, 
since owing to unavoidable cireumstances the number had to be 
issued before the author’s proof was returned. 
Page 788. For Ch. mazquital read Ch. mezquital. 
or Neomugil digneti read N. digueti. 

For Encinostomus read Eucinostomus. 

Page 789. For C. boveinus read C. bovinus 


For Ch. latevalis read Ch. lateralis 
For Charaeodon duitpoldi read Chien luit poldi. 
r Ps. retiaulatus read Ps. reticulatus. 
ia Heteraudria read Heterandria. 
For limantoun read limantouri. 
For Mollienesia formora read M. formosa. 
For Xiphophinus read Xiphophorus 
For Aelunchthys read Aelurichthys. 
For Netuma vacula read N. oscula. 
For Netuma clattena read N. elattura. 
For G. Kessleri read G. kessleri. 
For Anus read Arius. 
For Tachysurus Steindachneri read T. steindachneri. 
For Anus multeradiatus read Arius multiradiatus. 
For Cathorops gulorus read C. us. 
Page 790. For Tetragonopterus humitis read T. humilis. 
: or Dorosome read Dorosoma. 
Page 791. For Stercolepis read Stereolepis. 
For Mr. Alvin Seele read Mr. Alvin Seale. 
Page 796. For Dr. J. Graham Kew read Dr. J. Graham Kerr. 
Page 797. For Isusus read Isurus 


THE 


AMERICAN NATURALIST 


Vor. XLII January, 1908 


No. 493 


EXPERIMENTS IN GRAFTING 


PROFESSOR T. H. MORGAN 


COLUMBIA UNIVERSITY 


THESE experiments were undertaken primarily to find 
out whether it is possible by artificial means to induce 
regeneration in a part that does not regenerate under 
ordinary circumstances; and secondly to find out what 
kind of a structure will regenerate from the proximal 
end of so, highly specialized an organ as the limb of a 
salamander; for, while we know that from the distal end 
a new limb regenerates we have no information as to what 
will happen if the proximal end is exposed. Since the 
latter experiments gave more positive results they will be 
first considered. As it is necessary to keep the imb alive 
during the relatively long period required for its regen- 
eration it was necessary to graft it, in a reversed position, 

on to the same animal. ` 

The following method of grafting was employed. The 
leg was cut off, the skin loosened around the attached 
stump and turned back. The stump (composed of mus- 
cles, bone, nerves, etc.) was cut off higher up and the skin 
was then turned back. A pocket was thus formed. Into 
this: pocket the piece cut off was implanted, after being 
turned around so that its proximal end was directed out- 
wards. The skin was then drawn together by a ligature 
over the cut end. Since it is desirable to draw the skin 
completely over the exposed end without, however, press- 
ing too much on the grafted piece, I have found it desir- 

: : 1 


y 


La 


2 THE AMERICAN NATURALIST [VoL. XLII 


able to cut off a longer piece of the stump than will be 
required, and then to cut this in half, putting either half 
back into the pocket, which being incompletely filled, 
allows the skin to be drawn more readily over the end. 
The hind-limb being larger was used. The implanted 
piece, reversed in orientation, consists of bones, muscles, 
nerves, etc. The skin covering these parts is the old skin 
with normal orientation. Therefore, at least one ele- 
ment in the complex is not reversed. 

In some respects this method of grafting proved un- 
satisfactory, because the cut end of the stump is so near 
to the graft that the new material from the stump and 
that from the graft may easily become mixed, so that 
the results would be complicated. The shortness of the 
grafted piece is another source of difficulty, since the 
short piece may become displaced during the healing of 
the end. To overcome these difficulties I devised another 
method, in which however only a single organ has its 
orientation reversed. The hind leg was cut off at the 
knee, and the femur removed from the stump for nearly 
its entire length. It is then shortened by cutting off 
part of one end, and pushed back into its original posi- 
tion, but with its orientation reversed. Owing to the 
slightly bent shape of the femur, and its much enlarged 
knee-end, no chance for a mistake in its orientation is 
possible. This procedure proved superior to the first, 
although the problem involved is somewhat different. 

At ‘first the large salamander, Spelerpes ruber, was 
used. This is a terrestrial form. Later the somewhat 
smaller Diemyctylus viridescens was used. Both species 
withstand the operation well and regenerate readily. 
Serial sections were made of the limbs at different stages 
of their regeneration. 


REGENERATION FROM THE PROXIMAL END OF A 
REVERSED PIECE 
An examination of the preparations of those cases in 
which a cross-section of the limb was implanted in a 


No. 493] EXPERIMENTS IN GRAFTING 3 


reverse direction in the pocket of skin of the same limb 
shows that as a rule proliferation takes place from the 
cut ends of the bones, both of the graft and of the stump 
of the limb. In the majority of cases it is impossible to 
decide with certainty whether the bones of the new limb 
originate from one or from both sources. While such 
a combined formation would be of interest in itself the 
conditions are such as to make it impossible to assert that 
both proliferations do actually contribute; for, even if 
the new material from both sources is continuous with the 
new material of the regenerating part, we can not be 
entirely certain that both really take part, however prob- 
able this may seem. In a few cases, however, where 
the skeletal material of the new limb had connected with 
the proliferating periosteum of the grafted piece there 
was every indication that the new part was derived from 
the exposed proximal end. In all cases that have formed 
a new limb, the periosteum of the cut end of the leg- 
bones has formed a bar of cartilage connecting their ends 
with the nearest ends (the original distal ends) of the 
bones of the grafted piece. Two possible errors make 
other cases of doubtful value. The short pieces of 
grafted bones are often turned obliquely, or even side- 
wise in the end of the limb, due to the contraction of 
the skin as the end heals, or to changes that take place 
in the surrounding tissues. In most other cases, the 
periosteal tissue growing down from the cut end of the 
leg-bones passes around to one side of the grafted piece, 
and, with or without receiving contributions from the 
latter, forms the cartilage of the new limb. In fact, in 
some cases this can clearly be seen to have taken place, 
in others, while not so evident, the possibility of such a 
process exists and renders the result uncertain. 

In order to avoid this source of error. I adopted the 
second method of grafting described above. A long piece 
of the femur was grafted in a reverse position in 
the thigh. The length of the piece prevented its rota- 
tion, and at the same time by increasing the distance 


4 THE AMERICAN NATURALIST [ Vou. XLII 


between the distal end of the leg-bone and the proximal 
(now inverted) end of the graft it was possible to detect 
with greater precision the source of the material for the 
new bones. The presence of a single bone instead of two 
as in the former case also simplified the conditions. 
Despite these advantages, only a few cases were obtained 
in which the results seemed to show with great proba- , 
bility that all of the material for the new skeletal parts 
was derived from the exposed proximal end of the 
grafted piece. In such cases there was always established 
a cartilaginous connection between the cut distal end of 
the femur of the stump and the cut distal end of the 
grafted piece. The new limb is thus made up of a proxi- 
mal piece of the femur, connecting cartilage, grafted 
piece of reversed femur, new tibia, fibula, tarsalia and 
phalanges from the proximal end of the grafted piece. 
Evidences of absorption are generally seen in the grafted 
piece. How far this might ultimately go was not de- 
termined. 


Tam in Lee anp Lee in Tarn 

By means of the skin-pocket-method it is easily pos- 
sible to graft a short piece of the tail (without skin) 
into a pocket of the leg, and vice versa, a piece of the leg 
into a skin pocket at the cut end of the tail. I have made 
a few such experiments with Spelerpes ruber not without 
hopes that from the graft in the leg a tail might develop, 
and a leg from the end of the tail. The results proved 
otherwise, for, whenever regeneration occurred, the new 
material for a new leg came from the cut end of the old 
leg-bones the proliferating cells passing to one side of 
the grafted piece and the latter becoming absorbed. 

A similar process occurred in the case of a leg grafted 
in a tail; a new tail and not a leg regenerated. The 
experiment shows that care must be exercised in inter- 
preting the other cases where the same kind of organ 
is grafted in a reversed position. 


No. 493] EXPERIMENTS IN GRAFTING 5 


REGENERATION AFTER REMOVING A BONE some DISTANCE 
FROM THE Cut END 

In order to see what would happen if the bones are 
absent at the cut surface, the hind leg of Diemyctylus 
was cut off above the knee, the greater part of the femur 
was removed from the stump, and the skin sewed over 
the cut end. Regeneration of a new leg was delayed, 
but took place. The stump of the leg seemed to contract 
somewhat, so that the cut end of the bone was brought 
nearer to the cut end of the muscles. The prolifera- 
tion from the end of the bone must have grown down 
to the cut surface, and then, extending beyond this, given 
rise to the material for the skeleton of the new leg. The 
experiment shows the possibility of the same thing occur- 
ring when a grafted piece is pushed aside. Unless the 
graft block the proliferation from the bones of the stump, 
these may contribute material to the new limb. 


ÅTTEMPTS TO INDUCE REGENERATION IN THE LEG OF 
THE FRroG 

In order to see if regeneration could be induced in 
adult frogs numerous experiments have been made dur- 
ing three winters. Pieces of the leg were cut off, and 
grafted in skin-pockets in various ways, but without 
results. I hoped that the breaking down of such grafted 
pieces might incite the regeneration process, if its ab- 
sence in frogs were due simply to some retarding influence 
in the method of closure of the cut surface as occasionally 
occurs in pieces of other animals that have well developed 
powers of regeneration. 

Pieces of the leg of tadpoles (without the skin) were 
also inserted into the leg of the frog without inciting 
regeneration, but as different species were probably used 
for graft and stock, successful results were less to be 
expected. Pieces of the muscles and other tissues of the 
tadpole’s tail were inserted in skin-pockets of the leg of 
the frog but without effect. Since the tail of the tad- 
pole has remarkable powers of regeneration, it seemed 


6 THE AMERICAN NATURALIST [ Von. XLII 


possible that the presence of such tissue might excite 
the leg to regenerate, but this did not prove to be the 
case. Possibly, here also, the difference in species 
spoiled the result, but this seems unlikely, since it has 
been shown that young tadpoles of different species may 
be readily united and form permanent unions. 

It is well known that the skin of the frog has excellent 
powers of regeneration, yet when the leg is cut off it 
generally ceases further growth after the cut surface has 
healed over. It occurred to me that the pressure of the 
skin over the cut end might in itself prevent the further 
growth of the internal organs. To examine this possi- 
bility I cut off the fore-leg turned back the skin, cut off 
a piece of the stump, and then sewed up the end of the 
pocket. There was thus left a free space between the 
cut end of the stump and the end of the skin. Neverthe- 
less regeneration of the limb was not hastened. In other 
cases agar, or the coagulated white of the hen’s egg, was 
inserted into the pocket, on the supposition that as they 
were absorbed the regeneration might take place but 
nothing of the sort occurred. These experiments were 
undertaken before I became aware of the fact that the 
fore-leg of an adult frog may actually regenerate, but 
only after a long time and imperfectly, so that the experi- 
ments would be expected at most to facilitate or hasten 
the regenerative process which however they did not 
seem to do. In the winter of 1904-05 one frog that lived 
for several months, floating in the water, regener- 
ated a long outgrowth from the cut end of a fore-leg. 
The new part had one or two rudimentary finger-like 
outgrowths, but although the outgrowth was long it was 
very imperfect as a limb. This frog had had its leg cut 
off twice, the second time two months after the first 
operation. In some preparations of Mr. Goldfarb I had 
seen the great thickening of the periosteum that takes 
place after several weeks, and this suggested, that if the 
leg were cut off anew at this time, regeneration might 
take place. I have also obtained more recently two or 


No. 493] EXPERIMENTS IN GRAFTING ri 


three other cases of regeneration of a limb in this way, 
and in these the new foot was flat and broad, and plate- 
like, but with scant evidence of toes. That the regenera- 
tion of a new leg is not dependent on this two-fold opera- 
tion has been shown by Mr. Goldfarb who has also 
obtained cases of regeneration of the fore-leg of the frog 
after a single amputation. Since Mr. Goldfarb will des- 
cribe these cases in detail further description may be 
omitted here. 

The toad, being a more primitive member of the Anura, 
might be supposed to have greater powers of regenera- 
tion, but experiments have been less successful with it 
than with the frog. The thickening at the end of the 
bones forms a large knob, as it does also in the frog at 
first, but in the toad no subsequent changes appear to 
take place. 


EXPERIMENTS WITH LIZARDS 

During the summer of 1904, while enjoying the hospi- 
tality of the Marine Laboratory of the Leland Stanford 
University, I carried out many experiments with lizards, 
but since the results were purely negative they may be 
given in a few words. In the lizard the tail has the power 
to regenerate with great facility, but the legs appear to 
have no power of this sort. I tried grafting parts of the 
tail in skin-pockets in the legs, in the hope of inciting 
regeneration. In some cases large pieces were inserted, 
containing all of the tissues, in other cases pieces of 
single tissues, muscles, bone, periosteum, etc., were put 
into the pocket, but without producing the desired result. 
The lizards were kept alive in some eases for six to eight 
months without showing any signs of regenerating the 
leg during this time, but even the tail regeneration is not 
rapid. It appears, nevertheless, that the regeneration 
of the leg can not be induced by the presence in it of 
pieces of other parts of the body that have the power 
to regenerate. 


8 THE AMERICAN NATURALIST [ Vou. XLIL 


CONCLUSIONS 

Although the experiments undertaken in the hope of 
inciting regeneration in parts that do not do so ordi- 
narily, or imperfectly and only after a long time, have 
not given any positive results as yet, still even the nega- 
tive results are not without a certain theoretical interest. 
The experiments with the frog showed that the lack of 
power to regenerate, or only to regenerate imperfectly 
after a long time, is not due to the pressure of the skin 
on the cut end of the parts beneath. Tt is interesting to 
find that when after several months the internal parts 
begin to push out a new stump, as sometimes occurs, 
the skin is then also incited to regeneration, and will 
form a suitable covering for the parts beneath. It is 
plausible to suppose that this growth of the skin is due 
to the pressure of the new part from within. Other 
factors may also enter into the result, but that the pres- 
sure must be the main factor is shown by the failure of 
the skin to regenerate when other tissues, those of the 
tail for instance, are present, that have themselves the 
power to regenerate, but not finding suitable conditions 
for regeneration fail to form an embryonic knob. In its 
absence the skin is not incited to regenerate. The fact 
that the skin does not show any tendency to complete 
itself alone, although it has the power of regeneration, is 
important as showing that the possession of this power 
is not itself a stimulus that will lead to its development. 
Some other condition is necessary to call it forth, and in 
this case, that condition seems to be pressure from 
beneath. 

Other tissues in the leg may also have the power to 
regenerate, but fail to do so unless certain conditions are 
realized. This state of affairs may lead us to hope that 
with a better knowledge of the conditions we may ulti- 
mately control them, and I trust this may be a first con- 
tribution towards that end. 

That the muscles in the frog’s leg have the power to 


No. 493] EXPERIMENTS IN GRAFTING 9 


regenerate can be shown by cutting from the side of the 
gastrocnemius a square piece of muscle tissue. In the 
course of a few months I have found that the muscle 
regains its size, which seems to be due, in part at least, 
to the formation of new muscle, although hypertrophy 
of the remaining fibers may also assist in the enlarge- 
ment. 

There is some indication that the delay in the forma- 
tion of the new leg in the frog is due to conditions exist- 
ing in the bones or muscles and, as I have pointed out,? 
it is significant to find that in the vertebrates the loss of 
power to regenerate a limb appears where cartilage has 
been changed to bone. The result is not however due 
directly to the ossification, since the new material is 
derived from the periosteum and not from differentiated 
tissue. 

Especially interesting is the evidence showing that the 
introduction of material, itself capable of regeneration 
(as when the tail-tissue of the lizard is introduced into 
the leg-pocket) does not incite the leg to regenerate. If 
the process of regeneration is due to some enzyme, or 
_ other substance of this nature, that arises in an injured 
region, and whose presence incites the new growth, we 
might hope by introducing pieces of material capable 
of forming such substances to incite regeneration, but 
no such result followed. It would be unwise to lay too 
much weight on negative evidence of this kind, but the 
results as they stand indicate, perhaps, with some proba- 
bility, that the primary cause of regeneration is not to 
be found in this direction. 

Finally, to revert once more to the experiments that 
gave positive results. It has been shown that from the 
proximal end of a reversed femur new limb bones develop. 
This result calls for further analysis. It is clear that 
each level of the limb has the power to regenerate all 
of the parts lying more distal to it, and in all proba- 


1 The Harvey Lectures for 1806-7. 


10 THE AMERICAN NATURALIST [ Vou. XLII 


bility every level has potentially the power also to re- 
generate all the other parts of the limb proximal to 
that level. It is difficult to show that a distal part has 
the potentiality to produce more proximal parts, but the - 
facts make this interpretation highly probable. How 
much of the distal end regenerates depends in part 
on its relation to what is left in the stump, and in part 
on the necessity of forming a distal structure. Between 
these limits the intermediate parts are laid down. The 
proximal cut end of a limb must have the same poten- 
tiality of forming distal structures as has a distal end 
and in those cases where the possibility exists of forming 
either an anterior or a posterior structure, as in pieces 
of lumbriculus, for example, some other relation must 
determine that from one end of a piece a head always 
develops, and from the other end a tail. I have sug- 
gested that the direction of the gradations of the old 
material (as expressed in their differentiation) is the 
factor that regulates this result. If we apply these same 
ideas to the special case under consideration we might 
expect the proximal end of the leg (or any part of it) 
to regenerate only proximal structures; in other words 
to complete the proximal end of the femur and produce 
a scapula at the exposed end of the leg, and, theoretically, 
one might imagine the further development of a salaman- 
der around the scapula as a center. The facts are the re- 
verse. The conditions that determine in the case of the 
reversed femur what shall regenerate of the various pos- 
sible ones are not so simple as just described. In the 
first place, the detachment of the femur from the rest 
of the limb may soon lead to changes in it that cause 
it to lose that gradation of materials on which the po- 
larity of the new part depends. There is also the pos- 
sibility that the polarity of the other tissues may have a 
counterbalancing influence. But far outweighing these 
possibilities there is another consideration of greater 
weight. The special group of tissues found in such an 
organ as a limb may be capable of forming only one 


No. 493] EXPERIMENTS IN GRAFTING 11 


structure, if they form anything at all, namely, a leg, and 
not a salamander to take the extreme case. But why 
always the distal end of the leg and not the proximal, 
i. e., not femur and scapula? The determination of the 
distal end rather than the proximal must be due, I think, 
to the presence of the free rounded knob covered by the 
new skin which gives the stimulus for a distal structure, 
and the foot end of the leg is the only possible distal 
structure that exists for this organ. 

The case is parallel to the formation of a heteromor- 
phie tail in the earthworm, that develops, as I have 
shown, from the anterior end of a piece when cut be- 
hind the level of the twentieth segment, or thereabouts. 
Here also a distal structure develops, but the nature of 
the material is such that a tail rather than a head regen- 
erates. While polarity, as an expression of the grada- 
tion of the materials, is one of the factors that determines 
a result, it is not the exclusive factor. In Lumbriculus 
a head forms at the anterior end of a piece at nearly all 
levels and a tail at the posterior end. Here we must 
= assume that the kinds of materials are so equally balanced 
throughout the greater length of the worm that the po- 
larity determines the result, while in the earthworm and 
in the leg of the salamander another condition determines 
a different result. In the latter cases the kind of mate- 
rial, or the organ-complex, makes it possible for only a 
tail or a leg to develop at either end of the piece, and 
the presence of a free end determines that its new struc- 
ture must be the terminal part, hence a foot in the case of 
the salamander, and a tail in the case of the earthworm, 
is regenerated even from a reversed end. 


THE PHENOGAMOUS PARASITES 


By DR. CHARLES. A. WHITE 


SMITHSONIAN INSTITUTION 


Tue object of this essay is to describe in a popular 
manner the chief characteristics of the known kinds or 
groups of phenogamous parasites, to show their relation 
to one another and to normal phenogams, and to discuss 
their structure and habits with reference to the probable 
manner of their origination. In order to make a popular 
statement of the characteristics of each group of these 
abnormal plants and to discuss them clearly it is first 
necessary to summarize briefly the elemental structure 
and physiological ch teristics of the normal pheno- 
gams. I have chosen to do this in verbal terms a part 
of which are somewhat unusual, but which are believed to 
be specially appropriate to discussions of this kind. 

The elemental parts of a normal phenogamous plant 
are root, stem and leaves, the beginning of the differentia- 
tion of which structures is distinguishable even in the 
embryo; and to these are added, at the maturity of the 
plant, flowers and fruit. Every normal phenogam also 
consists of two incremental parts, an up-growing and a 
down-growing part, respectively, the latter entering the 
soil to form the roots. The normal phenogamous plant 
performs all its physiological functions within, and for, 
itself and lives independently of all other plants except 
in the matter of competition with them for the benefits 
of soil, moisture and sunlight, but the parasites escape 
the performance of those functions so far as nutrition is 
concerned. The normal plants derive the materials for 
their subsistence and growth from inorganic sources and 
elaborate them within their own tissues for their own use, 
producing thereby their new organic substance, but the 
parasites rob other plants of that substance in its elab- 

12 


No. 493] THE PHENOGAMOUS PARASITES 13 


orated condition. The supply of inorganic material 
is obtained by normal plants partly in a soluble and partly 
in a gaseous condition, the former being contained in the 
food-sap which the roots derive from the soil, and the 
latter in the atmosphere which surrounds the plant. The 
function of the root requires a constant accession of mois- 
ture, and that function is vital with relation to the other 
functions of the plant presently to be referred to. The 
action of sunlight is indispensable in the condensation and 
elaboration of those inorganic materials into new organic 
substance. An essential step in that elaboration of new 
material is the production of chlorophyl, which takes place 
partly in the bark of the growing branches, but mainly in 
the parenchyma of the leaves. Fully developed green 
Jeaves are therefore among the chief organs of normal 
phenogams, and their absence from the greater part of 
phenogamous parasites is due to the inability of those 
plants to produce chlorophyl. It is for these reasons that 
chlorophyl is so frequently mentioned in the following 
paragraphs. 

The reproduction of normal phenogams is by two meth- 
ods, namely, parturital’ and blastemal.2. These methods 
have such relevancy to the subject in hand that it will be 
frequently necessary to refer to them. The first is the 
conjugative method and provides for the hereditary trans- 
mission of specific and other systematic characters, the 
geographical distribution of species and the multiplica- 
tion of individual plants. It is periodically cyclic, the 
maturation of the seed ending one cycle and the germina- 
tion of its embryo beginning another. The second is the 
autogenous method and pertains to the growth and pres- 
ervation of the individual plant. Its operation is phys- 
ically continuous during the whole life of the plant, and 
every bud of the plant is connected with all the other 
buds by living somatic cells. The horticultural processes 
of budding and grafting consist of transferring blastemal 

* Parturio, to bring forth young. 


°? Basros, a bud. These terms are regarded as preferable to ‘‘sexual, ’ 
‘*asexual,’? ‘ — ’ ete., which are often used by writers. 


14 THE AMERICAN NATURALIST [ Vou. XLII 


reproduction from one plant to another. They are closely 
simulated by. some parasites in their manner of attach- 
ment to the host, but there are radical differences be- 
tween parasitic attachment and horticultural grafting. 

The two incremental divisions of every normal pheno- 
gam consists of an epitropic, and an apotropic? portion, 
respectively, separated by the tropaxis. The epitropic 
portion, beginning with the radicle at germination, enters 
the ground, divides into roots and rootlets, and estab- 
lishes the plant in position. This is primary epitropism. 
The apotropic portion at the same time extends upward, 
forming the stem and finally the branches, leaves and 
fruit. This is primary apotropism. The tropaxis is a 
theoretical dise at, or a transverse section of, the base 
of the stem from which growth proceeds in opposite di- 
rections. Its functional existence as a dividing plane is 
real and constant during tlie life of the plant, but it is 
structurally not clearly definable. That is, no material 
change of plant-texture occurs at the place where the 
upward and downward growth diverge, and no obstruc- 
tion to the flow of food-sap from one to the other portion 
exists there. Suckers, stolons, sprouts, ete., sometimes 
spring from roots, root-stalks or tubers, and become new 
plants. This is secondary apotropism. Roots or root- 
lets often spring from the stem or branches. This is 
secondary epitropism. A new or secondary tropaxis is 
formed in every case of secondary apotropism at the place 
where the upward growth begins and new roots turn down 
into the soil.4 

Such are the leading structural characteristics of nor- 
mal phenogamous plants, which constitute the mass of 


*For a full explanation of these and some of the following terms see 
my article in Science, N. S., vol. XII, pp. 143-146. 

* The terms ‘‘hypocotyl’’ and ‘fepicotyl,’’ meaning below the cotyle- 
dons and above the cotyledons, respectively, often have been used by authors 
to designate the apotropie and epitropie portions, respectively, of the germi- 
nating embryo. Those terms are inappropriate for such use because the 
place of attachment of the cotyledons rarely, and only accidentally, coin- 
cides with the place where upward and downward growth diverge, and the 
two places are often far apart. A case in whieh they are far apart is 
illustrated by the plantlet of Convolvulus as shown by Fig. 6, on page 28. 


No. 493] THE PHENOGAMOUS PARASITES 15 


the green vegetation of the earth. Abnormal phenogams 
constitute only a very small proportion of the great mass 
of vegetation, and yet the aggregate number and variety 
of their forms is really very great. Three general kinds 
of abnormal phenogams are recognized, namely, para- 
sites, saprophytes and symbionts. They have certain 
characteristics in common and often are visually similar, 
but they differ materially from one another in the manner 
of procuring their subsistence, and the habit of each of 
them in that respect may be either partial or complete. 
That is, a phenogam may be partially parasitic, sapro- 
phytic, or symbiotic, and partially normal; or parasitism 
_ may be associated in one and the same plant with sapro- 
phytism. While my chief object is to discuss the para- 
sites, it will aid in defining their characteristics to pre- 
sent a brief statement of those of the two other Pods of 
abnormal phenogams. 

Saprophytes derive their subsistence from dead organic 
matter in the soil which has not reached the stage of full 
decomposition. That matter yields a soluble portion to 
the food-sap which the plant obtains by its roots in the 
usual manner and, after some reelaboration, that portion 
is applied by the plant as new organic substance in the 
building of its tissues. Saprophytes, like vultures, hyenas 
and epicures, take their food in a partially decomposed 
condition and thrive upon it. Doubtless many plants that 
are properly regarded as normal are really in part sapro- 
phytic when their roots have access to organie manures, 
but only completely saprophytic phenogams are here re- 
ferred to. It is claimed by some investigators that com- 
pletely saprophytic phenogams sometimes produce chloro- 
phyl and develop green leaves, but those here discussed 
produce no chlorophyl, develop no functional leaves, and 
are therefore not green in color. Their reproduction, both 
parturital and blastemal, is normal and they grow from 
their roots in the soil like normal plants, with none of 
which are their vital relations antagonistic. Completely 
saprophytic phenogams, which only are now particularly 
referred to, are comparatively rare, especially in ordi- 


16 THE AMERICAN NATURALIST [ Vou. XLII 


nary soils. They are mostly confined to swampy and 
other moist soils that contain much decomposing vege- 
table matter, and to shady positions. It may be suggested 
that the abundance of disintegrating organic material 
contained in the soil in which these completely sapro- 
phytic plants grow furnishes so large a supply of ma- 
terial which is still useful for assimilation in the 
production of new organic substance that the entire leaf- 
function, including the production of chlorophyl, is 
suspended as being superfluous, and that this habit has 
become permanent and hereditary. 

Completely symbiotic phenogams live in enforced vital 
union with a fungus which adheres to and covers its 
roots, and through which it derives all its soil-subsistence. 
The roots being entirely enveloped, their normal function 
is destroyed and the fungus also assumes the office of 
purveyor of nutriment. As do other fungi, it obtains that 
food-material from decomposing organic matter in the 
soil and transfers a portion of it to its consort through 
their surfaces of contact. Although that food-material, 
when obtained by the fungus, is partially decomposed, 
and is received at second hand by the captive phenogam, 
the latter thrives upon it, and, its above-ground portion 
being free, the functions of vegetative growth and repro- 
duction are normally performed. Its leaves, however, are 
abortive or functionless and never green in color, for 
completely symbiotic phenogams do not, and do not need 
to, produce chlorophyl. Their failure to do so is doubt- 
less a direct result of the condition which is imposed upon 
its roots by its fungus consort. The vital relations of 
these strangely modified phenogams with other plants are 
normal, but their condition with relation to the fungus 
is apparently that of pitiable captivity. The usurpative 
control of their nutrition by the fungus suggests that 
these phenogams did not originate as symbionts by a pre- 
dilective departure from a self-supporting condition. 
Partial symbiosis of fungi with phenogams is not uncom- 


mon and is understood to be, at least in many cases, © 
mutually beneficial, but it has only incidental relevancy in 


No. 493] THE PHENOGAMOUS PARASITES 17 


this connection. One can hardly doubt that the complete 
symbiotic condition of those plants has been imposed by 
the aggressive increase of the fungus from its original 
condition of partial symbiosis, but the phenogam so fully 
acquiesces in it that the deficiencies of structure and func- 
tion which its imposed condition entails have become har- 
monious with that condition and hereditary. Even the 
embryo, at least in the case of Monotropa, or Indian pipe, 
and probably also in that of Sareodes, or the snow plant 
of California, has lost its differentiation into cotyledons 
and plumule. This is a significant coincidence with a 
similar condition which prevails in the embryo of many 
parasites, as will be shown in following paragraphs. 
Examples of complete symbiosis are few among pheno- 
gams, the most common case being that of Monotropa. 
All the older botanists believed, and some of them so 
stated in their text-books, that the species of that genus 
are parasitic upon the roots of woody plants. Later 
authors often have stated that Monotropa is saprophytic, 
but still later investigators have demonstrated that the 
plants of this genus are completely symbiotic. It will be 
. a disappointment to the older plant-lovers not to find their 
familiar acquaintance, the Indian pipe, discussed among 
the parasites on the following pages, but the facts which 
have been stated require its omission there. — 
Whatever view one may take concerning the two kinds 
of abnormal phenogams that are briefly defined in the 
preceding paragraphs, he instinctively regards the para- 
sites as a criminal class in the great community of honest 
plants. Their methods of parasitism are so varied, and 
each method is prosecuted with such vigor and con- 
staney, that it is necessary to review them with reference 
to those habits rather than to similarities and differ- 
ences of systematic structure. They all are at least ac- 
quisitive in their relations with other plants, and some of 
them are vigorously aggressive and raptorial. They all 
derive new organic substance from other plants, always 
from living ones, and apply it directly in the building of 
their own tissues. Some of them are annual, and some 


18 THE AMERICAN NATURALIST [ Vou. XLII 


perennial. Some are herbaceous, and some woody. Some 
of them attack only the epitropic, and some only the apo- 
tropic, portion of their host. Some are only partially 
parasitic, obtaining only a part of their subsistence in 
that manner, but a large number are completely parasitic, 
and thus obtain their entire support from other plants. 
The former obtain a part of their subsistence from the 
soil as normal plants obtain all of theirs. They also de- 
velop leaves and produce chlorophyl, but the complete 
parasites, with exceptions to be mentioned, develop no 
functional leaves and produce no chlorophyl, for com- 
pletely parasitic plants do not need to produce it. New 
organic substance, elaborated as already has been men- 
tioned, is of course necessary to the existence of the 
normal plants which produce it. It is no less necessary 
to the existence of the parasites, but they, not being able, 
or not predisposed, to produce it for themselves, obtain it 
by robbery from other plants. All of them are so de- 
praved that they acquire special hereditary habits of 
rapine, modify their structure, and even develop special 
organs with which to accomplish their thefts. The defi- 
ciencies and modifications of structure are correlated with - 
the respective kinds of parasitism, and they are invariable 
and heritable. Even the embryo of some of them is | 
structureless, not being differentiated into cotyledons, 
radicle and plumule. Indeed, some of the most vigorous 
of the parasites originate from embryos that apparently 
represent only a moiety of the normal phenogamic embryo. 
The leaves of normal phenogams are properly regarded 
as the chief organs concerned in the production of chloro- 
phyl, but if my assumption is correct that the agency of a — 
structural root is a precedent necessity in normal cases — 
of such production, the functional leaflessness of a para- 
sitic phenogam is a direct consequence of its rootlessness. — 
That is, because a rootless phenogam can produce no ~ 
sufficient quantity of chlorophyl, and because it procures 
_ its new organic substance by theft, it has no use for 
leaves. Therefore, those leaves which it morphologicall 
inherits remain undeveloped or functionless. This is the 


No. 493] THE PHENOGAMOUS PARASITES 19 


condition of complete parasitic phenogams, but those 
which are only partially normal supplement their honest 
gains by theft. They are all robbers, and obtain new 
organic substances from their hosts by methods which 
resemble grafting, budding and leeching, respectively. 
In the first two cases mentioned the embryo of the para- 
site is thrust into the living tissue of the host from which 
the resulting parasitic plant draws its nourishment, much 
. as do the bud and scion in cases of budding and grafting. 
In the other case special organs, namely, haustoria, are 
developed as instruments of robbery. These organs serve 
‘to draw new organic substance in liquid form from nor- 
mal plants, and they are as indispensable to the parasite 
which possesses them as are roots to normal plants. 
They are produced as small outgrowths from different 
parts of different parasitic species, sometimes upon the 
roots and sometimes upon the stem and branches. They 
are of wart-like, discoid, globular, or more or less irregu- 
lar form, and are sometimes single and symmetrical, but 
oftener in groups or clusters and shapeless masses. 
When single they are sometimes sessile and sometimes 
terminal on slender pedicels. They attach themselves by 
their free surface to the host, and so burrow into its sub- 
cortical and subcortical tissues that the growing cells of 
both plants are intimately commingled. Acting like 
suckers, they withdraw in liquid form the new organic 
substance which the host had prepared for its own use, 
much as a leech extracts blood from its victim. The 
haustoria of parasites are comparable with roots of nor- 
mal plants because, like roots, they are the instruments 
by means of which the plants obtain necessary supplies, 
but true haustoria are not roots nor morphological repre- 
sentatives of them. 

The foregoing remarks apply mainly to the general 
characteristics of the parasites as compared with sapro- | 
phytes, symbionts and normal plants. The special char- 
acteristics of the parasites are grouped and briefly sum- 
marized in the following synopsis. In remarks which 
follow each synoptical statement some of the more con- 


20 THE AMERICAN NATURALIST [ Vou. XLII 
spicuous of those extraordinary habits which members 
of the various groups possess and which have become con- 
stant and hereditary will be shown. Many of those habits 
are of wonderful character, and one almost feels that he 
is dealing with sentient beings of great cunning and law- 
lessness rather than with vegetal forms. 

The phenogamous parasites are so aberrant as regards 
both their structural and vital relations to other plants 
and to one another that it is difficult to classify them. 
Indeed, there is no logically recognizable correlation of 
any of the parasitic characters of the species in question 
with those which pertain to systematic classification. The 
following synopsis, prepared for the present occasion 
only, embraces seven groups the characterization of which 
is, so far as practicable, based upon the manner of para- 
sitism of the members of the 
respective groups and upon 
the peculiarities of their 
life history,. especially that 
phase of it which pertains to 
germination. 


Group I 
Seeds germinate upon the 
ground. Embryo differenti- 
ated into cotyledons, radicle 
and plumule, like normal em- 
bryos. Like normal plants 


Fic. 1. Diagrammatic pen- 
sketch, showing the position of 


haustoria at the places of contact 
of roots of the parasite and its host. 


natural size. 


also those of this group pro- 
duce chlorophyl. A part 
of their roots are attached 
by sessile haustoria to roots 


of other plants, from which 
they obtain ready-made organic substance in liquid form, 
and a part of them obtain food-sap from the soil in the 
normal manner. Therefore their parasitism is only par- 
tial. Examples: Euphrasia, Pedicularis, Castilleja and 
many others. 
The parasitism of the members of group I, which are 


No. 493] THE PHENOGAMOUS PARASITES ak 


mostly perennial herbs, is confined to limited underground 
pilfering. It is the simplest form of phenogamous para- 
sitism but it is as persistent and hereditary as are the 
more complex forms, and it is practised by a large number 
of genera and species which have numerous near normal 
relatives. Because they have normal roots and leaves 
and produce chlorophyl! they begin life with the ability to 
procure an honest living, but they seem to be unable to 
resist their inherited parasitic inclinations. The develop- 
ment of haustoria at the points of contact of their roots 
with roots of other plants begins after their germinative 
birth from a normal embryo and an early stage of full 
self-support obtained from the soil; but so firmly fixed 
is the habit of pilfering in these plants that when they 
have been experimentally forced to live honestly in good 
soil, but beyond the reach of roots of other plants, they 
have ceased to thrive, as if they were insufficiently 
nourished. 
Group II 

Parasites attached to the stems and branches of woody 
hosts upon the bark of which the seeds germinate, being 
affixed there by their glutinous covering. Embryo differ- 


2. Pen-sketch of a branch of Viscum album, the Old World mistletoe ; 
much reduced in size. A. Diagram showing the mode of attachment of the 
parasite to the host by the sinkers. 


entiated into cotyledons, radicle and plumule, and the 
plant consists of both epitropic and apotropic portions.. 
The latter is differentiated into stem, branches, leaves and 
fruit, as in normal plants. The leaves, and also the bark 
of the stem and branches, contain chlorophyl which is 
produced by the plant itself. The parasite is attached 


Pi THE AMERICAN NATURALIST [Vou. XLII 


to the host by ‘‘sinkers’’ which consist of specially modi- 
fied, but true, rootlets, although in function they simulate 
the haustoria of other parasites. The sinkers penetrate 
the bark of the host and obtain nourishment for the para- 
site from the growing tissues beneath it, much as food-sap 
is obtained from the soil by normal plants. The para- 
sitism is complete. Examples: The mistletoes. 
The members of group II are perhaps the most gener- 
ally known, at least by name, of all the phenogamous 
parasites. The family 
to which they belong, 
the Loranthacez, is a 
large one, and some 

= of its members differ 
considerably from the 
typical forms of mis- 
tletoe. Only Viscum 
album of the Old 
World, and Phora- 
dendron flavescens, 
of the New, however, 
are chosen to repre- 
sent group II on this 
occasion. These mis- 
Fig. 3. Pen-sketch of a branch of Phora- toes differ from the 
oo Aiur New World mistletoe; members of all the 
other parasitic groups 

in being perennial woody parasites upon woody hosts, and 
also in their method of parasitism. That method is pecu- 
liar because it simulates grafting, because morphologically 
its ‘‘sinkers’’ are true rootlets and not haustoria, and 
because the passage of sap from host to parasite is by 
those rootlets and not through such harmoniously joined 
cells as are formed between the graft and its stock. 
Mistletoes have been known to become parasitic upon 
other mistletoes, but in their choice of a host they usually 
give preference to trees that are not botaniecally related 
to them. Their structure, both embryonal and mature, is 
so nearly normal that one might believe them capable of 


No. 493] THE PHENOGAMOUS PARASITES 23 


leading an honest life in the soil, but so firmly is their 
predatory habit established by heredity that they never do 
so. Their seeds will germinate successfully only on the 
bark of living trees, and their embryos, although struc- 
turally perfect, are evidently unable to develop in the soil. 
When germination of the seed begins the radicle pierces 
through the dry bark of the host as if driven by some ex- 
traneous force; and it sometimes enters the bark of a 
branch from its under side, showing that gravity is not 
that impelling force. It lifts the strong bark by its in- 
crement beneath, and sends the sinkers into the growing 
layers. The cells of those layers and the cells of the sink- 
ers hecome vitally commingled much as do the somatic 
cells of the scion and stock in common grafting, but not 
quite so harmoniously. This parasitic root-grafting is 
remarkable because the parasites and their usual hosts 
differ from each other in botanical relationship far more 
than do any scions and stocks that can be artificially 
grafted with success. 

Because the mistletoes obtain full nourishment from 
their hosts their parasitism is complete, and yet, unlike 
other completely parasitic phenogams, they produce chlo- 
rophyl in their own tissues. The production of chlorophy] 
by the mistletoes is apparently due to the fact that they 
have retained morphological representation of true roots, 
notwithstanding their parasitism. While the mistletoes 
have retained more of the structure and functions of nor- 
mal plants than have other completely parasitic pheno- 
gams, their draft upon the vitality of their hosts is great, 
and it doubtless would be more apparent if the latter were 
less vigorous. 

Group III 

Seeds, having the embryo differentiated into cotyle- 
dons, radicle and plumule, germinate upon the ground and 
there produce plants which begin to grow in the soil in 
the normal manner. By their earlier roots they are par- 
tially parasitic after the manner of group I, but, sud- 
denly, the whole plant becomes epitropic and enters the _ 
soil bodily by burrowing, much as does the peanut pod 


24 THE AMERICAN NATURALIST [ Vou. XLII 


when ripening. It there branches freely, assuming the 
form of a large complex blanched rootstock, and becomes 
wholly parasitic. It passes its whole mature life under 
ground except that some of its branches rise above ground 
to flower, but those branches always die when the fruit 
has ripened. Its earlier parasitism is by sessile haus- 
toria, which are soon discarded, and its later parasitism 
is by haustoria-tipped tendrils, sometimes erroneously 


PN 
MIP S 
W a 


a a 

T A 
Sa) AG 
G \\ 7 

A Sr. 

K. Vr 

raat e aea 


ON a 


K 


Fic. 4. Lathræa squamaria; pen-sketch after Kerner. The dotted line rep- 
resents the surface of the soil. Only a small part of the underground stems and 
branches is shown in the figure, together with tendrils bearing the pediculate 
haustoria. 


called roots or rootlets, which issue from the under- 
ground stem and branches. No chlorophyl is produced 
and no functional foliage or functional roots are devel- 
oped after the plant begins its burrowing. Example: 
Lathrea squamaria. This group has no known American 
representatives. 


No. 493] THE PHENOGAMOUS PARASITES 25 


The species which has been chosen to represent group 
III is a European form and is quite distinct in certain 
respects from even its nearest botanical kindred, and it 
possesses habits that for variety and extent of abnor- 
mality are not surpassed, and apparently not equalled, 
by any other plant. It begins life normally, as do mem- 
bers of group I, which it then closely resembles. The 
presence of chlorophyl in the plumule of its plantlet and 
the development of early rootlets seem to indicate an 
. honest destiny for the plant, but its subsequent acts al- 
most suggest its utter abandonment to a groveling life. 


Group IV 

Seeds germinate upon the ground, producing an annual 
herbaceous plant. Embryo filiform and coiled within a 
mass of albumen in the seed; not differentiated into coty- 
ledons, radicle or plumule. The resulting plantlet retains 
the filiform structure of the embryo without differentia- 
tion, except that the part which becomes the lower end of 
the plantlet is slightly enlarged. As .the embryo uncoils 
the larger end enters the ground a little, but sends no 
rootlets into the soil and therefore derives no true food- 
sap therefrom. The smaller end points upward and the 
plantlet elongates as a single thread-like stem until it 
comes in contact with some freshly growing part of an- 
other plant. It there attaches itself by quickly developed 
haustoria, derives from the helpless host its first sufficient 
nourishment, and becomes a branching vine. It then 
reaches out for other hosts by more or less numerous 
branches, and the part below the first haustorial attach- 
ment quickly withers and dies. The branches grow rap- 
idly and bear an abundance of flowers and seed. The 
plant never naturally produces chlorophyl, and develops 
neither true roots or functional foliage. The parasitism 
is complete. Examples: Cuscuta of many American and 
European species, and Cassytha of many Australian, New 
Zealand and East Indian species. 

The members of groups I, IT and II are all developed 
from perfect embryos, like those of normal plants, their 


26 THE AMERICAN NATURALIST [ Vou. XLII 


parasitism and abnormal structures being developed after 
germination. The remaining four groups are not only 
deficient in structure at maturity, but they originate from 
embryos which are also deficient in structure. The first 
of those four groups to be considered is especially repre- 
sented in our country by the genus Cuscuta which contains 
many species, commonly known as dodder. They are 
often found growing plentifully in fields, thickets ‘and 
waste places during the summer 
months, their yellowish tangled 
masses making them conspicuous 
among the green vegetation. The 
embryo of Cuscuta gets very lit- 
tle sustenance from the albumen 
which envelops it in the seed be- 
cause the seeds are small; and it 
is because the plants develop no 
roots that they get no real nour- 
ishment from the soil. Never- 
theless, the plantlet grows rap- 
idly, somtimes to several inches 
in length, before it reaches a host; 
and although it is so slender it 
possesses great vegetative vigor. 
Me. 5. Cuesta Ruro ‘This vigor is conspicuously oP 
pea, parasitic on a hop vine. 
Sessile haustoria are shown Servable in the subsequent growth 
site and heat ntact Of para OF those species which often pro- 
fusely festoon shrubbery, and 
even trees, securing their hold upon, and their sustenance 
from, the tender twigs by means of their haustoria. 
Other species no less vigorously attack the smaller plants 
and field crops with which they come in contact. 

The parasitism of Cuscuta differs from that of the 
other groups in being effected by climbing as a vine from 
plant to plant, and by lateral haustorial contact of the 
stem and branches of the parasite with those of the host. 
In the case of the other groups whose parasitism is above- 
ground the success of the depredating plant depends upon 
the propitious position which the seeds may accidentally 


No. 493] THE PHENOGAMOUS PARASITES 27 


obtain; but the plantlet of Cuscuta, after its germination 
upon the ground seems, by the movements of its free end, 
to start out in search of opportunities. It adjusts its 
mode of life to prevailing conditions by delaying its own 
germination about a month later than that of its prospec- 
tive victims of annual growth, and it is not discouraged 
by failure of its first effort to find a host. In that case it 
falls down upon the ground, shriveled and apparently 
dying, but if soon, or even within a few weeks, some be- 
lated normal plantlet should spring up near it, or some 
growing branch should droop and touch it, the victim is 
quickly seized upon by the apparently dying plantlet. 
Such tenacity of life and apparently dominant purpose in 
a slender, organless mass of vegetable cells is no less than 
marvelous. 

Because the plantlet of Cuscuta develops no root or 
rootlets it evidently possesses no real representation of 
the epitropic portion of a normal plantlet, or at best, not 
more than a moiety of it which lies immediately subjacent 
to the tropaxis. The rapid upward growth of the fili- 
form plantlet indicates that at least a considerable part 
of the apotropic portion is therein represented. More- 
over, because it has no cotyledons or plumule it follows 
that the entire plantlet of Cuscuta represents only the 
stem of the normal plantlet, or that portion of it which 
comes between the cotyledons and the uppermost root- 
lets. The accompanying a Fig. 6, illustrates ‘the 
foregoing statement. 

The upper end of B, Fig. 6, not reaching above the 
upper dotted line, indicates that the plantlet of Cuscuta 
possesses no representative of either cotyledons or plum- 
ule. Its downward extension a little below the lower 
dotted line similarly indicates the fact that its lower end 
enters the soil a little way, but that it does not represent 
enough of the epitropie portion of the normal plant to 
give origin to a root, or any rootlets. This comparison 
shows that the whole plantlet of Cuscuta represents 
only the stem of the plantlet of Convolvulus. 

The descriptions which have been given in the preced- 


28 THE AMERICAN NATURALIST [Vou. XLII 


ing paragraphs of the structure, germination, life habits 
and method of parasitism of Cuscuta apply in every im- 
portant detail to Cassytha. Even the general aspect of 
the latter plants is such that an American or European 
seeing them for the first time instinctively regards them 
as dodders. Nevertheless the structure of their flores- 
cence and fruitage leaves no room for doubt of their close 


e*eee8 


B 
Cc 


tee Bs 


Fic Diagraphic illustration sd ‘ee relation of the embryo and plantlet 
of Cuscuta to the plantlet of Convolvu 
An early plantlet of coca with its first root and rootlets, its 
stem, cotyledons and the first leaf of the plumule, not yet expande 
. The pias plantlet of Cuscuta of nearly the same stage of growth 
from the seed as A, 
The upper goons ergy Paha A just a little below the place of attachment 
of the cotyledons. The lower dotted line represents the surface of the soil 
and also the position of e tropaxis of A 
C. Embryo of Cuscuta, at the beginning of germination. Much enlarged. 


relationship to the Laurel family, while all the species of 
Cuscuta are nearly related to the Convolvulacex. 


Group V 
Seeds germinate upon the ground. Embryo filiform 
and not differentiated into either cotyledons, radicle or 
plumule. Its protruding end, or offshoot, penetrates the 
soil after the manner of a radicle, sometimes to the depth 
of several inches, but as it sends off no rootlets it derives 
no true food-sap from the soil. The upper end, or that 


fae ae ARR SS ag CE et GR ree eS 


No. 493] THE PHENOGAMOUS PARASITES 29 
which in the normal embryo would bear the plumule, is 
not developed. If the descending end comes in contact 
with no living root of another plant the whole embryo 
dies, although the soil may be abundantly fertile. If it 
reaches such a root it be- 
comes attached to it and 
develops a tuberous mass 
at the placée of contact. 
From this mass spring out- 
growths which penetrate the 
bark of the root-host and 
blend intimately with the 
growing layer beneath it, 
where they act as haustoria. 
In this mass, also, by a kind 
of blastemal germination, 
buds, or substituent plant- 
lets, are formed which pro- 


Diagraphic illustration 


duce the flowering stems. 
No functional foliage and 
no true roots are developed, 
and no chlorophyl is pro- 
duced. 

The parasitism is com- 


plete. Examples: the 
broom-rapes and related 
genera. 


The parasites of group V 
belong to the Orobancheæ, 
the broom-rapes being 
chosen as typical members. 
They are vigorous in their 
growth and aggressive in 
their parasitism, some 0 


Rie, T. 
f the manner of germination and 
florescence of the broom-rape family, 
and of the structural relation of its 
embryo to the normal dicotyledonous 
embryo. 
A. Dotted outline of a normal 
plantlet introduced only for compari- 
son. 

. Offshoot of a broom-rape em- 
bryo. The upper moiety only may be 


longed underground, its fre 
coming attached to the root-host by a 
tuberous enlargement. ; 

©. The root-host. 

Flowering stalk of Aphyllon 
unifiorum springing from the tuberous 
nd of the offshoot. The horizontal 
dotted line indicates the surface of 

soil, 


the 


them being very destructive of cultivated crops; espe- 


cially hemp and tobacco. 


Like Cuscuta they delay 


their own germination until their prospective victims 
have germinated and grown sufficiently to serve their 
purpose. The seeds of those species which are parasitic 


O 


50 THE AMERICAN NATURALIST [ Vou. XLII 


upon cultivated crops seem sometimes to remain in the 
soil without germination more than one season, and to 
germinate when a new cultivated crop is planted. The 
accompanying figure represents the manner of germina- 
tion of a member of group V and the growth of its flower 
stem. 

Figs. 5 and 7 respectively represent two parasitic 
plants which, although they originate from physically 
similar embryos, are so widely different in their mature 
structure and habits that the following comparison is 
thought to be desirable. The seeds of both these parasites 
germinate upon the ground, but the resulting plantlet 
of one of them grows upward and that of the other down- 
ward, in search of a host. The plantlet of Cuscuta grows 
_ upward, which is attributed to the assumed fact that its 
embryo possesses a considerable representation of the 
apotropic portion of a normal plantlet, and little or 
no representation of the epitropic portion. No part 
of the broom-rape embryo grows upward, presumably 
because it possesses no representation of the apotropic 
pertion of a normal embryo. Its whole embryo seems 
to represent only a moiety of the stem of a normal 
plantlet which lies subjacent to its tropaxis and above its 
rootlets. The bud from which springs the flowering stalk 
of broom-rape is not a part of the embryo proper, as is 
the plumule of the normal embryo, but a result of sec- 
ondary germination. 


Group VI 

Seeds germinate only above ground and, like those of 
the mistletoes, only upon a living woody host; usually 
upon the stem and branches, but sometimes upon exposed 
roots. Embryo filiform and without either cotyledons, 
radicle or plumule. No true roots or functional foliage 
is developed, and no chlorophyl is produced. The em- 
bryo, by its distal or protruding end, when emerging from 
the seed, sharply and vigorously penetrates the bark of 
the host and sends haustorial processes into the cambium 
layer, and even into the alburnum. A single flower, some- 


No. 493] THE PHENOGAMOUS PARASITES 31 


times sessile and sometimes having a short stem, issues 
from the host at the place of entrance of the embryo. The 
parasitism is complete. 

Examples: The rafflesias and related forms. 

One of the most remarkable characteristics of group VI 
is that the individual plants of many of its species reach 
the lowest structural limit of the phenogam. That is, 
each one of such plants consists of a single flower which 
is sessile upon the bark of the host, or apparently some- 
times upon its cambium layer. In other cases the plant 
consists of a short, 
single scaly stem be- 
sides the flower. The 
sessile species are ex- 
amples of flowering 
plants reduced to the 
flower alone, assum- 
ing that the haus- Fic. 8. Pen-sketch of Raflesia padma, 
torial processes at its together with an _ undeveloped bud ; sessile 

upon a branch of its tree-host. This species 
base represent the attains a diameter of eighteen inches when 


fully expanded in flower; but that is only half 
torus, as they seem to the diameter of the largest species of Raflesia. 


do. While the nor- 
mal phenogam consists of root, stem and leaves, all of 
which are necessary to serve the purpose of the com- 
ing flower and fruit, the sessile Rafflesias throw the re- 
sponsibility of all else upon the host and furnish only 
the reproductive organs for their own perpetuation. 
They serve that purpose effectively, however, although 
they are rootless, stemless, branchless and leafless plants. 
And yet they are no more lacking in vitality than are the 
most vigorous members of the vegetable kingdom. 
Although the seeds of Rafflesia, like those of the mistle- 
toes, germinate upon the bark of a woody host, their em- 
bryo is not of normal structure, as is that of the mistletoes, 
but is simple and filiform, as is that of groups IV, V, 
and VII. Because the embryo of Rafflesia is not differ- 
entiated, and therefore has not a true radicle; and because 
it is not able to germinate upon the ground, it is assumed 
that the protruding end of its offshoot does not represent 


32 THE AMERICAN NATURALIST [ Vou. XLII 


the radicle of a normal embryo. If this assumption is 
correct it follows that the plant is destitute of normal epi- 
tropism and that the force with which the offshoot of the 
embryo pierces the bark and growing wood of the host is 
an abnormal and violent form of epitropism. It is also 
assumed that because the embryo of Rafflesia has no 
plumule the flower does not represent primary apotropism 
for the plant, but abnormal secondary apotropism as does 
that of the broom-rapes. The remarkable plants which 
constitute group VI are divided into many well-defined 
species and a considerable number of genera. Some of 
them bear the largest flowers that are known among 
plants, the largest being more than three feet in diameter, 
but some are very small. All are natives of warm cli- 
mates, mostly of Asia, Africa and the adjacent islands. 
A few American species are known, all of them small. 
One very small species which is found in Texas and 
Mexico is sessile in great numbers upon a papilionaceous 
shrub, and is hardly more than one eighth of an inch in 
diameter when in full bloom. 


Group VII 

Group VII consists of a remarkable and varied series of 
tropical and subtropical phenogamous parasites known as 
the Balanophoree. Some of them have large and showy 
flowers, and some of them have so great resemblance to 
fungi that the older botanists regarded them as such. All 
of them are parasitic upon roots of woody hosts, beneath 
soil which is usually rich in vegetable mold. The seeds 
germinate upon the ground. The embryo is not differen- 
tiated into cotyledons, radicle and plumule, butit is fili- 
form as is that of groups IV, V and VI, and its offshoot 
penetrates the ground in a manner similar to that of the 
broom-rapes. In the manner of their germination and in 
the underground origin of their flowering stems from a 
tuberous or amorphous mass, these plants also resemble 
the broom rapes; but in their florescence and fruitage 
they are very different. They produce no chlorophyl and 
they are all without either true roots or functional leaves, 


No. 493] THE PHENOGAMOUS PARASITES 33 
although some of them have moderately large, scaly rep- 
resentatives of leaves. 

There are probably other forms of phenogamous para- 
sitism, but the seven fore-mentioned groups are the best 


. 9. Pen-sketch of Balanophora seagate a native of the Comoro 
icant “of the east coast of Africa. After One quarter natural size. 
The leaves of this poy igir large, are got and. not functional. 

A. Amorphous, fleshy ma B, B. Flower stems springing from the mass. 
C. The root-host. 


known, and they serve to show that they are all depraved 
members of the class phenogams, and not predatory mem- 
bers of a separate class. 


PRELIMINARY REPORT ON AN INVESTIGATION 
OF THE SEASONAL CHANGES OF 
COLOR IN BIRDS 


C. WILLIAM BEEBE 


New YORK ZOOLOGICAL PARK 


Ir is a well-known fact that the males of many species 
of birds assume a special nuptial plumage at the begin- 
ning of the breeding season, sometimes radically different 
from the plumage of the winter. Especially marked 
examples are scarlet tanagers (Piranga erythromelas), 
bobolinks (Dolichonyx oryzivorus), and certain weaver 
birds of the genera Vidua and Pyromelana. 

We know that the native birds mentioned above lose 
their brilliant breeding plumage in the early fall and» 
assume a winter dress approximating that of the female. 
When we consider such a case as the scarlet tanager and 
the summer tanager (Piranga rubra rubra), the former 
changing annually from scarlet to green, the latter re- 
maining scarlet at all seasons, we have an interesting 
difference in two closely related species giving definite 
data from which to work. The problem which I have set 
myself, and at the solution of which I have made but the 
merest beginning, is, What is the cause of, or what factors 
determine, this seasonal change in the males of the 
scarlet tanager and the bobolink? 

So unbroken is the field of research in all such prob- 
lems as this that the most hopeful way of working is to 
clear the ground by gradually eliminating all negative 
factors, and thus narrowing down to the important dy- 
namic qualities of the environment. 

On hastily reviewing the field, the following factors 
have occurred to me as being the most important in bring- 
ing about, either directly ontogenetically, or indirectly 
phylogenetically, seasonal change of color: 

34 


No. 493] CHANGES OF COLOR IN BIRDS 35 


General condition of the bird’s body—whether fat or 
thin. 

Food—whether vegetable or animal. 

Blood pressure—whether raised or lowered. 

Sexual organs—whether active or inactive. 

Inheritance. 

Temperature—heat or cold. 

Conditions of humidity or aridity. 

This list is of course merely tentative, and the factors 
enumerated are by no means equal, and some are depend- 
ent on others. But they represent what I selected when 
first I began the experiment detailed below, as a con- 
venient review of the field before me. 

This experiment concerns only factor number one, the 
condition of fatness or thinness of the bird’s body and 
its influence on moult and indirectly on the sequence of 
annual changes of color. 

We know that birds, such as bobolinks and tanagers, 
after the cares of the breeding season are always thin 
and in poor condition. The externally worn and bedrag- 
gled condition of the feathers is reflected in the physically 
deeper part of the body, and the keel of the breast-bone— 
that true index of a bird’s condition—often is very con- 
spicuous under the skin of the breast. Not until the fall 
moult is past do the birds improve much in condition and 
then they become unusually fat. I think that these few 
facts hold true of most birds. 

Fat is something to guard against in captive birds, and 
in the Zoological Park I find it necessary to have a 
weekly examination made of many of the small birds; 
this being a matter of regular routine. Birds from the 
various cages are caught and carefully examined, and the 
proportions of the food ingredients—fat-producing and 
the opposite—are regulated according to the condition of 
the birds. 

One year ago last summer I took full-plumaged speci- 
mens of male scarlet tanagers and bobolinks in full song 
and plumage and put them under careful observation. 


36 THE AMERICAN NATURALIST [Vou. XLII 


None of these birds had been allowed to breed, and so, 
although it was rather late in the year, they were still 
in the height of vocal and physical condition. They were 
all tame, and although during the period of experimenta- 
tion they were confined in rather small cages, each bird 
in a space’ 12 x 12 x 24 inches, yet their plumage remained 
in almost perfect condition. 

I began gradually to cut off the supply of light and 
slightly to increase the amount of food. This caused a 
corresponding decrease in activity of the birds, and an 
almost immediate increase of weight. The danger of 
obesity in caged birds is that any excitement or sudden 
fright may cause a blood vessel to break, or in some other 
way bring about death from apoplexy. Consequently I 
kept the tanagers in a room where they were never dis- 
turbed and where no noise ever made possible the chance 
of an untimely end. 

A month later when the time for the fall moult arrived, 
the birds were living ‘‘the simple life’’ in a dim illumina- 
tion and, although consuming a normal amount of food, 
were exercising but little. The time for the fall moult 
came and passed and not a single feather was shed. The 
cages were made of mosquito-netting wire and would have 
confined any moulted feathers. In addition to this, the 
birds were examined every third day, and nowhere on the 
body was there any sign of moulted or of new, incoming 
feathers. On blowing away the plumage from the breast, 
the yellow sub-cutaneous layer of fat could be distinctly 


seen. 

In brief, the birds skipped the fall moult entirely and 
appeared to suffer no inconvenience whatever as a result. 
As far as appearance went they were in perfect health, 
showing only the symptoms of inactivity produced by an 
excess of adipose tissue. Early in the experiment the 
songs of the birds diminished and finally died away al- 
together, and when a good layer of fat had been acquired 
the birds seldom uttered even a chirp. 

From time to time a bird was gradually brought into ` 


No. 493] CHANGES OF COLOR IN BIRDS 37 


the light for a week or two and meal-worms were added to 
its diet. This invariably resulted in a full resumption 
of song. Even in the middle of winter a tanager or a 
bobolink would make the room ring with its spring notes 
and with this phenomenon was correlated a slight de- 
crease in weight. This phase of the experiment could 
not be repeated indefinitely, however, for the song period 
seemed limited, just as it is under normal ¢éonditions, 
although the nuptial plumage remained unchanged 
throughout the winter. As one of my keepers pithily put 
it, ‘‘ We have their calendar twisted backward.’’ 

I found that a sudden alteration in temperature— 
either lower or higher—wrought a radical change in the 
physical metabolism of the birds. They would stop feed- 
ing almost altogether, and one tanager lost weight rapidly. 
A few feathers on the neck fell out, and in the course 
of some two weeks this bird moulted almost every feather 
and came strongly into his normal winter plumage of 
olive green. The metabolism set up by the change in 
temperature, in its extent and rapidity, seems compar- 
able only to the growth of a deer’s antlers. 

Early in the following spring individual tanagers and 
bobolinks were gradually brought under normal condi- 
tions and activities, with quick result: just as the wild 
birds in their winter haunts in South America were at 
that time shedding their winter garb and assuming the 
more brilliant hues of summer, so the birds under my 
observation also moulted into the colors appropriate 
to the season. The old scarlet and black feathers fell 
from the tanagers and were replaced by others of the 
same color; from buff, cream and black, the bobolinks 
moulted into buff, cream and black! There was no ex- 
ception; the moult was from nuptial to nuptial; not from 
nuptial to winter plumage. The dull colors of the winter 
season had been skipped. 

I think we thus have proof that the sequence of plu- 
mage in these birds is not in any way predestined 


through inheritance bringing about an ETE E e oe . : 


38 THE AMERICAN NATURALIST [Vou. XLII 


cession, in the case of the tanager, of scarlet—green, scar- 
let—green, year after year, but that it may be inter- 
rupted by certain external factors in the environmental 
complex. 

The further significance of these results I leave to 
others, or until I have more complete data, checked by 
results derived from control of the other factors of the 
environment. It would be worse than useless to formu- 
late any theories at the present incomplete stage of the 
experiments. 

The scarlet tanager is of especial interest, as I have 
said, on account of the absence of such an annual change 
of color in its near relative, the summer tanager, and 
experiments with the latter species may shed some light 
on the subject. Other experiments concerning half and 
even quarter moults are yielding interesting results and 
will soon be reported upon. 

There is a great satisfaction in thus making even the 
merest beginning at threshing out these problems, which 
in their general evolutionary aspect are of far wider 
application than in the Class Aves alone. And work 
along these lines is all the more enjoyable because it 
entails the loss of no life as concerns the birds themselves. 


NOTES ON THE BREEDING HABITS OF THE 
SWAMP CRICKET FROG, CHOROPHILUS 
TRISERIATUS Wied. 


A. H. WRIGHT AND A. A. ALLEN 


CORNELL UNIVERSITY 


Axsourt nineteen years ago, Professor O. F. Hay! while 
searching the ponds about Irvington, Indiana, for Am- 
bystomas and their eggs discovered the eggs of Choro- 
philus triseriatus. The eggs were well advanced in 
development and his observations on the succeeding 
stages constitute most of what we know of the life-his- 
tory of the swamp cricket frog. 

While on a similar search for Ambystoma jeff ersoni- 
anum in the suburbs of Buffalo one of us found several 
males and females of Chorophilus and, subsequently, 
some anuran eggs which for a time remained unidenti- 
fied. Inasmuch as the identification of these eggs fur- 
nished data upon the mating, egg-laying process and 
fresh eggs of Chorophilus triseriatus—the period pre- 
ceding that of which Professor Hay’s observations treat 
—it seems advisable to present this material. 

During the last weeks of March Chorophilus appears 
in considerable numbers about the outskirts of Buffalo. 
The male chorus which is easily distinguished from that 
of Hyla pickeringii rises from most of the swamps and 
temporary ponds, even within the city. The singers 
themselves, however, are not easily seen, for, upon ap- 
proach, they become silent and further disturbance, causes 
them to disappear into the vegetation at the bottom of 
the pond where they remain until some time after the 
disturbance has ceased. Then, from the most remote 
corner the chorus is gradually taken up until the whole 
pond resounds with the ringing notes. In taking up the 

‘Hay, O. P. Notes on the Life History of Chorophilus triseriatus. 
Am. NAT., 23 September, 1899, No. 273, p. 770. 

39 


40 THE AMERICAN NATURALIST [ Vou. XLII 


chorus, the assurance evidenced by the single voice is 
extremely contagious. This fact makes it possible to 
overcome some of the difficulties which ordinarily present 
themselves in collecting this species. One has but to 
place the first captures in a bag or other close receptacle 
and carry it on one’s person. The prisoners chirp up 
and sing as boldly as though undisturbed in their natural’ 
haunt. Their voices elicit an almost immediate response 
from those in the pond. Indeed, at such a time, with 
a little practise one can wade about, while they sing on 
all sides and dip up as many as one desires. 

In this way after spending several hours in capturing 
the first two, 30 specimens, 25 males and 5 females, were 
taken in less than an hour. These were isolated for the 
purpose of studying the egg-laying process. On the way 
from Buffalo to Ithaca (April 1, 1907), they were kept in 
the same box, but the sexes in separate compartments. Dur- 
ing the transit, the males chirped considerably and the 
females deposited 200 or 300 eggs without attendant males. 

The Embrace.—The usual Hyla type of embrace ob- 
tains, the forearms of the male being pressed into the 
axille of the female. The males at the height of the 
breeding period evince an ardor almost as eager as that 
of the common toad. Sometimes, they embrace each other 
and as many as 4 or 5 males have been found in one bunch. 

A peculiar embrace recorded June 16, 1907, may serve 
to illustrate how long this nuptial impulse may remain 
with the male. April 1, 1907,.about 30 Hyla pickeringii, 
1 female, 29 males, and 5 male Chorophilus triseriatus 
were placed in one jar. Between April 1 and June 16, 
these swamp cricket frogs ate nothing, yet, after 24 
months, and, evidently long past the breeding time, an 
emaciated male Chorophilus triseriatus mated with the 
single female Hyla pickeringii. The embrace was axil- 
lary, but sometimes, possibly due to weakened condition, 
the male partially lost his hold. Then, his arms slipped 
along on the sides of the body of the female until he came 
to the lumbar embrace, the arms touching each other on 

the ventral side. The male disliking this embrace sought 


No. 493] THE SWAMP CRICKET FROG 4] 


to move along the body of the female to the customary 
amplexation of his species. A similar weakened condi- 
tion may explain the occasional records of lumbar em- 
braces with other captive anurans which normally adhere 
to the axillary type. 

At the height of the breeding season the male Choro- 
philus, like other Anura, often grasp moving objects or 
animals which are in the same aquarium with them. 

The Egg-laying.—On the morning of April 2, 1907, the 
25 male Chorophilus triseriatus were placed with the five 
females. At 9:50 A. M., the first mated pair was recorded 
and, within 20 minutes the female began laying. With 
one exception, she chose a different perch for each egg- 
laying period, thus giving a bunch to each period of sexual 
activity. In one instance she sought the same perch 3 
successive times. She ordinarily grasped the branch 
with her forelimbs. When about to deposit she brought 
one heel up to the stem and near the vent. Farther back 
the other foot held the stem with the toes. Each time, 
just before the voidance of eggs the female raised her 
anus and the male stretched to bring his vent near that 
of the female. 

This pair consumed 24 hours in laying a complement of 
500 or 600 eggs. The process required about 90 fertiliza- 
tions and emissions. The intervals between a simultane- 
ous fertilization and emission and a similar succeeding 
period ranged from 16-35 seconds, the common range 
17-30 seconds, the modal time, 20 seconds, the average, 
21 seconds. Each time, from 2-10 eggs were voided, 
being emitted in small strings, a condition which could 
be most readily seen when occasionally the eggs were 
unattached to the stem and hung down from the vent of 
the female. In such cases the strings broke after 10-12 
eggs were voided. There were 16 periods of egg-laying, 
20-70 eggs being usually laid at a period and each period 
consumed from 2-7 minutes, 3 minutes being the modal 
time. Always after a period of laying the pair arose to 
the surface of the water. These 15 periods of rest varied 


42 THE AMERICAN NATURALIST [Vou. XLII 


from 2-17 minutes, the mode being 4 minutes. All the 
eggs were laid in water 66° F. 
An account of the first pair follows in tabular form: 


| 1.2 n | 
=o ee ee 3 5 a 
pag |338| 3555 | gg [3.8 
Pe mee | oo 35 2 S23 | noe code ang Each 
EBS pee $8.5 B= a Sg | mission. 
Z Hos | 238% Z 5 a 
| He E | 
—] —| | 
1 | 3 min | ‘a | 8 | 
|? té | 1 6 
a yet ee) eae 3 | 
ce eae Vee 9 | 20, 25, 20, 17, 22, 17, 20, 21 secs. 
5 |5 nae eae 14 | 20, 18, 17, 20, 22, 20, 20, 20 « 
6a #) og i | 4 | 18 20, 18 «“ 
eee ge | 7 | 35,17, 20, 25, 23, 18 “ 
Ss S ge] 6 | 22, 23, 25, 20, 18 « 
2 2) 16 =| 7 | 20, 20, 22, 17, 17, 17 “ 
10 |4 A 3 ae i 9 | 28, 27, 27, 22, 22, 20, 23,17 “ 
1b ia 2, 2. 88.7. 6 | 
| ps] ieee 
13 se, 3 bot | 
14 | oe 2 i 
15 | goe] 2 I: 
16 | 13 « Pa ae 3 | 


The Eggs.—The second pair were in the embrace at 
noon. At 1:30 P. M. they began laying and by 4:30 
P. M. their complement numbering 600 eggs was laid. 
The complements of females of Chorophilus triseriatus 
vary from 500-800 eggs. The mature eggs of one ripe 
female, 3.2 em. long, numbered 418 for the right ovary, 
354 for the left, or a total of 772. 

The eggs are laid in bunches and are attached to twigs, 
branches, fine roots or grass stems. Each bunch contains 
from 30-100 eggs. An actual count of 5 bunches gave 
50, 80, 70, 68, 70, respectively. 

The measurements of eggs gave the following results: 
the average vitellus diameter of 38 eggs was 1.1 mm., the 
mode, 1.2 mm., the range, .9-1.2 mm.; the average envelop 
diameter was 5.8 mm., the mode, 5.6 mm., the range 
usually 5.0-7.8 mm., though sometimes as low as 3.0 mm. 

The vegetative pole is white; the animal, brown or 
black. The envelop about each individual egg makes up 
the larger portion of the jelly mass of a bunch, yet, there 
is in addition, some connecting jelly. This has a loose 
gelatinous consistency and does not envelop the whole 
mass as in Ambystoma. 


MODERN METHODS OF EXCAVATING, PREPAR- 
ING AND MOUNTING FOSSIL SKELETONS 


ADAM HERMANN 


Heap PrEPARATOR, DEPARTMENT OF VERTEBRATE PALEONTOLOGY, 
AMERICAN MUSEUM oF NATURAL HISTORY 


The work of collecting and preparing fossil bones is so 
well known in the museums of America that it is not my 
intention to explain in detail how to take up bones in the 
field and to prepare them in the laboratory. Some of the 
most modern methods adopted in the American Museum 
of Natural History may, however, be of interest. 


Fretp Work 

Too much emphasis can hardly be laid upon the proper 
treatment of bones in the field, because very crumbly but 
precious specimens may be saved by proper treatment, 
while, on the other hand, good specimens may be ruined 
by wrong treatment. 

Up to recent years collectors in the field have used 
almost exclusively gum arabic for saturating soft bones 
in order to harden them, and while practical for very por- 
ous bones it does not penetrate sufficiently into less por- 
ous ones, so that they become hardened on the outside 
only, remaining crumbly inside. Another disadvantage 
is that gum will absorb moisture and loses its binding 
properties in damp weather. Shellac will penetrate the 
bones much more thoroughly than gum, and when suffi- 
ciently dry will leave them much harder and absolutely 
waterproof. For the last three or four seasons our col- 
lectors have used a solution of shellac in place of gum 
arabie with very good results; and this can be recom- 
mended for any field work wherever the fossils are porous 
and badly preserved. Brown shellac is better as it dis- 
solves more easily and it is stronger, and should be used 

43 


44 THE AMERICAN NATURALIST [ Vou. XLII 


wherever practicable, but for light-colored bones white 
shellac is preferable, as it will not discolor the bones. 


PREPARING Bones IN THE LABORATORY 

Bones treated in the field with a solution of shellac usu- 
ally arrive in the laboratory in better preservation than 
those treated with gum òr glue-water, and much less care 
is necessary to prevent wetting in freeing them from the 
matrix or burlap cover. Numerous methods are employed 
to remove the matrix from the bones, according to the 
condition of the specimens. While a good-sized chisel is 
practical on a large and well-preserved specimen, small 
and delicate bones may be freed more securely with so- 
called harness awls of different sizes, bent and hardened 
to suit as a gouge and as a scratcher for softer matrix. 
Wherever the system of pneumatic chisels can be intro- 
duced it may be of great importance, especially for 
lighter chiseling of not too hard rock; it works very rap- 
idly and with less i injury to the specimens, as I had oppor- 
tunity to observe in the Field Museum of Natural His- 
tory at Chicago. 

I have found in my experience that a moderately strong 
solution of gum arabic used with alabaster plaster is a 
good and very practicable cement with which to ‘fasten 
pieces together and is the best cement for all ordinary 
bones. When used in the right proportions it holds very 
well, at least as well as the expensive cements, so much 
advertised. I find that the best and most substantial 
plaster for restoration work is made by mixing the plaster 
in a solution of yellow dextrine which can be easily dis- 
solved in boiling water. The dextrine solution should not 
be too strong; the right strength is indicated when the 
solution is of a light coffee color. Too much dextrine 
causes the plaster to crack when dry. 

So-called plasterine or modelling clay furnishes a very 
good material for moulds for rough casting. In this work 
the bones are slightly coated with glycerine and pressed 
in both peaks of the slay mould in such a way that they 


No. 493] MOUNTING FOSSIL SKELETONS 45 


can be lifted out without changing the shape of the mould. 
The two halves are then placed together properly and 
filled with plaster, which makes a fairly accurate cast. In 
many cases I have made the casts larger than the objects 
by moving the specimen to and fro in the mould to en- 
large the cavity. When modelling missing bones much 
time is saved by casting a bone in this manner and then 
modifying the form to suit, with knife and awl, instead of 
modelling the missing bones in clay. 


MOUNTING OF SKELETONS 

The mounting of fossil skeletons is a problem which 
can not be explained in a general way. Every skeleton 
has to be treated according to its size, shape, and con- 
dition. Skeletons from the size of a cat up to that of a 
large dog, to be mounted free, can be supported with 
light soft steel, so that the mounting shows very little. In 
case the vertebræ are not to be made detachable for study 
purposes, a flat rod may be run through the neural canal, 
which makes the neatest mount. 

Limbs and ribs supported with flat soft steel, fitted 
close to the bones, look very well and the mounting is 
very inconspicuous. All soft bones may be bored and 
fastened to the supports by screws or pins; harder bones 
by means of very small flat bands, fitted around the bones 
and fastened on the main supports with pins or screws. 

I may mention another method which I have introduced 
in the American Museum that may prove to be valuable 
for other museums. Skeletons which are soft enough, so 
that the bones ean be bored, can be mounted so that every 
bone is easily detached in the following manner: The 
back-bone may be supported by a soft steel rod (flat or 
half round) running under the vertebral column. Fittings 
to slide over the rod can be cast in bronze without great 
expense. Each fitting has a pin fastened to it which runs 
into the centrum of the vertebra, holding it firmly. Pins 
made stationary by being fastened in the supporting rod 
do not answer as in many cases it is impossible to get 


46 THE AMERICAN NATURALIST [ Vou. XLII 


the individual vertebre in or out of the column without 
moving the adjacent vertebre and pins. After the limbs 
have been temporarily set up and the flat or half round 
steel fitted flush to the bones, holes may be bored in the 
supports and in the bones at the proper places and brass 
tubes inserted and fastenéd in the bones with a mixture 
of shellac and whitening, which holds them very firm. 
Before the tubes are inserted a thread should be cut 
inside the tube to which the supports can be screwed very 
securely. This makes the bones easily detachable. This 
method is desirable for all skeletons with soft bones, small 
or large, and especially large skeletons, such as the Mam- 
moth or Mastodon, can be mounted with comparatively 
few rods or uprights. I can not recommend any style of 
iron or steel for all purposes as that largely is a matter 
of individual taste. I myself prefer half round, soft 
iron for all large skeletons to be fitted along the bones. 
For very small skeletons, small flat steel is preferable. 
The so-called channel iron makes good rib supports for 
all larger skeletons, as there is in the channel a suitable 
place for the nuts of the screws. 

A very practical tool to use in mounting skeletons, es- 
pecially larger ones, is the ‘‘electric drill.’’ It can be 
attached to any electric light block, and is a great labor- 
saving tool, which I can recommend very highly. We have 
one in use in our laboratory which weighs eight pounds; 
it cuts a }-inch hole, can be handled very easily, and can 
be used to drill holes in any bone or iron without taking 
them out of place. 

Another new feature of importance is the over-head rail 
or trolley system. As installed in our laboratory, a com- 
paratively heavy rail is fastened to the ceiling, on which 
trolleys with hoisting blocks attached can be rolled very 
freely to and fro. Skeletons suspended by these blocks 
can easily be raised or lowered, or moved from one end 
of the room to the other. This system is of great im- 
portance for economy in mounting very large skeletons. 
To suspend small skeletons while in operation we use 


No. 493] MOUNTING FOSSIL SKELETONS 47 


steel rods screwed to tripods of different sizes for up- 
rights with a horizontal bar fastened by means of clamps, 
which allow it to be moved up and down. This is a simple 
apparatus and is very useful for suspending skeletons of 
not too large dimensions. 

To dispense with most of the plumbers’ fittings in 
mounting skeletons we have introduced during the past 
few years a mode of splitting steel at the end, to act as 
braces and in other ways, opened and flattened and 
screwed to the uprights and other supports. This per- 
haps takes a little more time than to use so-called plumb- 
ers’ fittings, but it appears as an entirely different style 
of mounting. 

Wherever electric power is available labor-saving ma- 
chines can be installed, such as drilling machines for 
heavy work, rotary saws for splitting and cutting steel 
and brass, small turning lathe attachment for corborun- 
dum wheels, and rotary diamond saws for large section 
cutting. All these appliances just mentioned we have 
attached to one large lathe run by a one-horse power 
motor, although a little stronger motor may be recom- 
mended. A small gas-blast furnace with a one third or 
one half horse power motor for the blower makes a suffi- 
ciently strong forge to heat a two-inch steel bar and we 
find this in our laboratory indispensable. — 

During later years we have introduced numerous other 
convenient tools, but it would take too long to mention 
them all here. 


ISOLATION AND SELECTION IN THE EVOLU- 
TION OF SPECIES. THE NEED OF 
CLEAR DEFINITIONS 


JOHN T. GULICK 


Tae discussion concerning the factors in organic evo- 
lution has been obscured by the diversity of meanings 
given to the same terms by different writers, and some- 
times by the same writer. What do we mean by isolation, 
by selection, by environment, by evolution? 


DIFFERENT MEANINGS GIVEN TO ISOLATION 

I think that in Darwin’s books isolation is always used 
to designate the prevention of free-crossing between dif- 
ferent groups by means of factors lying outside of the 
groups, such as geographical barriers, but it has since 
been extended to mean the prevention of free-crossing by 
any means. Professor Kofoid, in his article in Science 
for March 29, 1907, gives the word this broader meaning 
in one place; but he must use it in a more limited way, 
when in the last sentence of his article, speaking of what 
DeVries finds in the elementary species ‘‘coincidently 
appearing’’ in the evening primrose, he says: ‘‘Isolation 
plays no part in their origin or continuance.’’ I have not 
found any statement by DeVries maintaining that ele- 
mentary species remain distinct forms from the original 
stock, when free-crossing with the original stock contin- 
ues. In my volume on ‘‘Evolution, Racial and Habitu- 
dinal,’’ pp. 5, 69-70, 155-156, I call attention to a mutation 
arising in certain species of snails, and probably pro- 
ducing complete isolation between the new form and the 
old, though both are occupying the same tree. The her- 
maphrodite snail is so constructed that it seems impos- 
sible for one of sinistral form to cross with one coiled in 
the opposite way; but in the Hawaiian Islands there are 

48 


No. 493 | ISOLATION AND SELECTION 49 


a number of species presenting both forms. If direct 
crossing is impossible, it follows that the only chance for 
continued connection between the two forms is through 
the subsequent mutation of one or both of the forms; and 
we know that in some species this occurs in a small per- 
centage of the offspring of each generation. 

That isolation is not a necessary condition for the pro- 
duction of this mutation is shown by the fact that it rises 
suddenly in the midst of an intergenerating group; but 
the fact that it remains a distinct form, returning to the 
original form in only a small percentage of the offspring, 
seems to be due to the fact that by its structure it is pre- 
vented from crossing with the original stock. In other 
words, structural isolation, which is one form of auto- 
nomic isolation, produces racial demarcation and initial 
segregation, opening the way for intensive segregation, 
through the introduction of divergent forms of selection. 

That natural selection is not the cause producing this 
mutation is shown by the fact that the old form and the 
new form are equally adapted to the same environment. 
I, however, maintain that the structural isolation pro- 
duced by the mutation prepares the way for the introduc- 
tion of permanently divergent forms of selection. 


DIFFERENT Forms or SELECTION 

In the case of selection as in that of isolation, we find 
autonomic as well as heteronomic forms. Artificial selec- 
tion as applied by man to the propagation of domestic 
plants and animals is a heteronomic factor; and in order 
to obtain permanently divergent races from the same 
stock, certain divergent variations or mutations are sub- 
jected to divergent forms of selection, while at the same 
time the different types are artificially isolated, unless 
there are autonomic factors holding the types apart. 
Such factors are preferential mating due to sexual and 
social instincts, or some degree of segregate fecundity; 
and in plants prepotence of pollen on the stigma of the 
same type, or flowering at different seasons. Natural 
selection is a form of heteronomic selection; for, as de- 


50 THE AMERICAN NATURALIST [Vor. XLII 


scribed by Darwin, it is subject to change, only as the 
group is exposed to changed external conditions resulting 
in the survival and propagation of an average type dif- 
fering more or less from the average birth type. Dar- 
win also carefully described one form of autonomic se- 
lection, which he called sexual selection. In my volume 
on ‘‘Evolution, Racial and Habitudinal,’’ I have called 
attention to social and filioparental selection, and several 
forms of impregnational selection, besides endonomic 
selection, in which the different methods of using the 
same environment, adopted by isolated branches of the 
same species, lead to the survival of different types of 
variation. These and`other forms of autonomic selection 
must be considered in any complete analysis of the factors 
producing two or more divergent species from one original 
species. 


VARIATION AND HEREDITY AND THEIR CONTROL 

If my analysis of the factors producing divergence is cor- 
rect, the active cause is found in the powers of variation and 
heredity possessed by the intergenerating group, while the 
conditions controlling, shaping and molding the varia- 
tion and heredity are those that are designated by the 
terms isolation and selection. Isolation produces demar- 
cational segregation; and divergent forms of selection in 
the isolated groups will produce intensive segregation, if 
isolation at the same time continues to hold the groups 
apart. 

Romanes describes selection as a form of isolation, be- 
cause its influence in controlling variation and heredity is 
due to its preventing those that survive from crossing 
with those that perish before propagating. That the in- 
fluence of both isolation and selection is due to the pre- 
vention of free-crossing is certainly true, and, as I have 
further pointed out, both classes of factors cooperate in 
producing segregation. It think, however, that it is in 
better accord with the meaning that writers on natural his- 
tory have usually given to the two terms to define isola- 
tion as the prevention of free-crossing between groups of 


_ 


No. 493] ISOLATION AND SELECTION 51 


organisms existing at the same time. In certain cases the 
isolative process may be selective at the same time; and 
so demarecational and intensive segregation progress to- 
gether; as is seen when the strong and courageous migrate 
together, leaving the weak and timid in the old habitat. 


DIVERSITY IN THE Usk OF A COMPLEX ENVIRONMENT 

An illustration of the wide divergence that may take 
place in a single family distributed over a small area is 
found in the Achatinellide, a family of snails found only 
on the Hawaiian Islands. Some genera of this family are 
found only on the ground, others chiefly on the trunks and 
branches of the trees, others on the leaves of the trees and 
shrubs. Ages of divergent evolution have made the indi- 
viduals of each genus entirely incapable of crossing with 
those of other genera; but in the case of closely related 
varieties and species occupying different species of trees 
in the same valley the conditions are very different. 
These are cases in which the continued isolation can not 
be attributed either to external barriers or to physiological 
incompatibilities. The different methods of using the 
environment, whether due to habits or to inherited charac- 
ters, is the real cause of the isolation. Again, of the ten 
genera of this family some are confined to one or two 
islands, though the vegetation and other conditions sur- 
rounding the family are much the same on the seven 
islands of the group. The condition explaining the small 
area occupied by any one of the five hundred species of 
this family is the limited power and opportunity for migra- 
tion or transportation; and the great variety of types pre- 
sented is undoubtedly due, first, to the power of variation 
possessed by isolated branches of the same species while 
using like environments in the same way; and second, to 
the variation in isolated groups introducing divergent 
methods of using the same complex environment and so 
subjecting themselves to divergent forms of selection, 
even when no external barriers hold them apart. 

In Science for March 30, 1906, Dr. Ortmann refers to 
species of crawfish subjecting themselves to diverse con- 


52 THE AMERICAN NATURALIST [Vou XLII 


ditions, in isolated positions, by diversity in their ‘‘eco- 
logical habits.” He describes them as ‘‘cases of ecolog- 
ical (or binomic) isolation, where no ‘barriers’ in the 
ordinary sense are present.’? In the relations of 
Hawaiian snails such cases are not infrequent. Even 
when the conditions in the environment with which the 
organism deals are extremely simple, the divergent groups 
of the original stock may adopt several different methods 
of dealing with these conditions, and with marked success 
in the use of each method. A fine illustration of this fact 
is found in the different species of Triposolenia, a genus 
of pelagic protozoa described by Professor C. A. Kofoid, 
in the University of California Publications, Zoology, Vol. 
3, Nos. 6, 7 and 8, December 11, 1906. After considering 
.the nature of the several different types found coexisting 
in the same region, ‘‘in the surface waters of the sea,’’ he 
concludes that, ‘‘The utility of each of the complexes of 
characters is sufficient for their preservation without the 
necessity of calling in natural selection to account for 
their differentiation and continuance.” (See pp. 121, 
123.) 


Causes OF THE EARLIER Forms or DIVERGENCE 

In the discussion that has appeared in Science during 
the past two years, the chief interest has centered around 
the question of the causes of the earliest forms of diver- 
gence. One method of inquiry has been to observe 
whether in a given family of organisms the most nearly 
allied species and races are found in the same or in sepa- 
rate districts. If with great uniformity the nearest allies 
are found in separate districts, there is good reason to be- 
lieve that initial demarcation has been due to geographical 
barriers, or at least to loeal isolation. If the analysis al- 
ready given is correct, the first step in divergence must be 
sought either in some process of migration, or transporta- 
tion producing local isolation; or in some variation in 
form, or habits of feeding, or instincts for mating, or time 
of flowering, or in prepotence of pollen, or in some other 
quality producing incompatibilities, and so producing 


No. 493] ISOLATION AND SELECTION 53 


autonomic isolation. In such creatures as snails, it would 
seem that the different forms of impregnational isolation 
do not often arise before a considerable degree of diver- 
gence has been reached; for usually the most nearly re- 
lated races, or varieties of Achatinella are found on sepa- 
rate groves of the same species of trees, in different parts 
of the same valley; while the most closely related groups 
of varieties, that are classed as separate species, are 
usually found in separate valleys; though sometimes in 
the same valley, but living on different species of trees. 

In the case of plants, I have seen closely related species 
growing beside each other, and in some such cases they 
are found to flower at different months of the year, and in 
other cases it would probably be found that they are held 
apart by the prepotence of pollen of a given species on 
stigmas of the same species. In some of these cases 
where the present form of isolation is undoubtedly auto- 
nomic, it may be impossible to say whether the new type 
was not first developed in a few individuals, that for a 
generation or two were partially isolated geographically 
or locally in some sheltered nook. 


Do New Types CONTINUE IN SPITE or F'Ree-Crosstne? 

As we have already shown in certain species of Hawai- 
ian snails, a sudden mutation may arise, which by its very 
constitution is prevented from crossing with the parent 
stock; and in such cases it is evident that a permanent 
type may begin with the mutation. But is there any proof 
that a mutation that freely crosses with the original stock 
will remain unchanged, each type thriving and remaining 
unblended with the other? If the mutation is the domi- 
nant form, it may be granted that it will in time over- 
~whelm the original form; but can two closely related 
races or species freely cross with each other, for many 
generations, without either type being affected by the 
process? For an answer to this question I would refer 
the reader to an article by Robert Greenleaf Leavitt in 
THE Amertcan Narurauist for April, 1907. On pp. 214- 
217 he gives quotations from Professors Davenport, 


54 THE AMERICAN NATURALIST [ Vou. XLII 


Castle and Forbes, showing that ‘‘ Everywhere unit char- 
acters are changed by hybridizing.’’ This testimony is 
chiefly from those who have experimented with the cross- 
ing of animal forms, but even in the case of plants, there 
is reason to believe that when free-crossing continues di- 
vergence is checked. There is reason to believe that even 
with plants the controlling factor in each case of con- 
tinuously divergent evolution is either some form of 
heteronomic isolation or some form of variation intro- 
ducing autonomic isolation. 


Moritz WaGner’s THrory AND My THEORY WERE Iso- 
LATED AND DIVERGENT FROM THE BEGINNING 

Moritz Wagner, in his ‘‘Law of the Migration of Or- 
ganisms,’’ was the first to insist on the importance of geo- 
graphical isolation as a factor in evolution, but when he 
asserted that without geographical isolation natural selec- 
tion could have no effect in producing new species he 
went beyond what could be sustained by facts. My own 
theory, though it did not take form till four years later, 
was reached without any knowledge of his, and therefore 
in complete isolation from his; and when they came to- 
gether for comparison they were found to be quite di- 
vergent. 

In March, 1868, Moritz Wagner read a paper before the 
Royal Academy of Sciences at Munich on ‘‘The Law of 
the Migration of Organisms,’’ and in 1873 an English 
translation of a fuller paper by him entitled ‘‘The Dar- 
winian Theory and the Law of the Migration of Organ- 
isms’’ was published by Edward Stanford, of London. 
It was through this pamphlet that I became acquainted 
with his theory concerning the impossibility of the pro- 
duction of new species except when and where migration 
establishes a colony geographically isolated from the 
original stock. In this paper we read: ‘‘The constant 
tendency of individuals to wander from the station of 
their species is absolutely necessary for the formation of 
races and species’? (p. 4). ‘*‘Where there is no migra- 
tion, that is, where no isolated colony is founded, natural 


No. 493] ISOLATION AND SELECTION ' Bb 


selection can not take place” (p. 59). These and many 
other passages of similar import indicate how fully he 
recognized the importance of isolation, and how at the 
same time his theory was a denial of some of the facts in 
the origin of species. The following are some of the facts 
with which his general theory as well as his special state- 
ments were in conflict: 

1. That, through change of climate and of other condi- 
tions due to geological changes, the whole fauna and flora 
of an island like Iceland might be subjected to new forms 
of selection producing a complete change of many species 
into new species, without any chance for migration. 
After the publication of my article in Nature, July 18, 
1872, in which I emphasized the importance of isolation, I 
met Darwin at his home, and he called my attention to 
Wagner’s theory, and suggested that it did not correspond 
with the facts of nature, especially on this point. 

2. That the influence of geographical isolation in pro- 
ducing divergence, and in opening the way for selection 
to cooperate in producing divergence, is wholly due to its 
prevention of free-crossing, and that the same result may, 
in various ways, be brought about by divergent habits or 
instincts, or other incompatibilities, while the isolated 
groups remain in the original habitat of the species. 

3. That divergence does not necessarily require the in- 
fluence of different forms of selection. 

4. And that different forms of selection do not neces- 
sarily depend on exposure to unlike environments; for 
diversity in the forms of selection may be due to diversity 
in the methods of using the same environment adopted by 
isolated branches of the same species. 

In August, 1872, I read before the British Association 
for the Advancement of Science a paper on ‘‘ Diversity 
of Evolution under One Set of External Conditions,’’* in 
which the conditions just mentioned were briefly stated. 
In two subsequent papers entitled ‘‘ Divergent Evolution 
through Cumulative Segregation,” and ‘‘Intensive Seg- 

1 This paper was soon after published in the Linnean Society’s Journal, 
Zoology, vol. XI, pp. 496-505. 


56 THE AMERICAN NATURALIST (Vou. XLII 


regation,’’ read before the Linnean Society in 1887 and 
1889, and published in their Journal, the subject was more 
fully discussed, and since then in my volume on ‘‘Evolú- 
tion, Racial and Habitudinal,’’ published by the Carnegie 
Institution, my view of the factors of organic evolution 
has been presented, with special relation to their inter- 
action on each other, and the close correlation between 
the evolution of habits and the evolution of racial charac- 
ters. It is to this last-mentioned phase of the subject that 
I have hoped that I might call special attention. I regard 
this influence of acquired habits in the control of the 
forms of selection as of great importance, especially in 
the evolution of the higher classes of animals, and in the 
races of mankind. 


MEANING OF THE TERM ENVIRONMENT 

In all my discussions, I have been careful to give a 
uniform meaning to the term environment. When treat- 
ing the evolution of species, or of smaller groups of in- 
tergenerating organisms, the environment is, in my lan- 
guage, always the set of influences lying outside of the 
group under discussion, and is never used to designate the 
influence of one part of the group upon another part, as, 
for example, the influence of parents upon offspring, of 
males upon females, of the strong upon the weak. In the 
generalizations made by some writers, it is impossible to 
decide whether the environments referred to are intended 
to include these reflexive influences or not. But even with 
the broadest interpretation of the term environment, I 
can not accept the statement often made that there is no 
divergence in branches of the same species unless they are 
exposed to different environments. 

Such a conclusion seems to be based on the assumption 
that all transformation in organisms is due to adaptations 
giving more or less advantage to the forms that survive, 
and ignores the fact that in many species there are count- 
less variations of a non-utilitarian character. It also 
fails to recognize the fact that isolated groups of indi- 
viduals of the same variety, exposed to the same external 


No. 493] ISOLATION AND SELECTION 57 


environment, and also to the same internal influences 
producing selection, may still, before many generations 
have passed, adopt different methods of dealing with the 
external environment, or introduce divergent forms of 
sexual or social selection, or of some other form of reflex- 
ive selection. The divergence, in such cases, is explained 
by the power of the species to vary, and by the proba- 
bility that the variation will introduce new methods of 
meeting surrounding conditions. F. W. Headley, in his 
volume on ‘‘Problems of Evolution” (on pp. 146-149), 
gives illustrations of how branches of the same species 
may adopt ‘‘alternative methods of adjustment to the 
same environment,” and yet in the same book (on p. 
103) we read: ‘‘If the environment remains unchanged, 
evolution ceases,’’? and on p. 153—‘‘ Nothing but change 
of environment can lead to further evolution.” His mind 
seems to cling to the old statements of general laws, 
though he has come to recognize a class of facts that are 
quite at variance with these old statements. 

It therefore appears that we need not only a clear and 
consistent use of terms, but a clear and consistent state- 
ment of the facts of the organic world, in their bearing 
upon the changes that take place in organisms. I have 
carefully studied O. F. Cook’s article in Science of March 
30, 1906, and his previous papers to which he refers in 
that article. The chief difference in our estimates of the 
factors of evolution seems to me to result from a differ- 
ence in the meanings that we give to the word evolution. 
In my use of the word all changes and divergences in the 
inherited and acquired characters of organisms are in- 
‘cluded. The chief factors I find to be variation and 
heredity in an intergenerating group moulded and con- 
trolled by isolation and selection. Fuller statements will 
be found in my book on ‘‘ Evolution, Racial and Habi- 
tudinal,’’ pp. 60, 79-80, and 138. Of these factors Dr. 
Cook says that variation and intergeneration relate to 
evolution, but isolation and selection, though ‘‘factors of 
species-formation, are not at all factors of evolution.”’ 
It is evident that this difference in our enumeration of the 
factors of evolution is due to the different meanings that 
we give to the term evolution. 


NOTES AND LITERATURE 
EVOLUTION AND HEREDITY 


Darwinism To-day.‘—‘‘Charles Darwin was the foremost scien- 
tifie man of the entire nineteenth century, and I think he must 
also be termed the greatest Englishman of his time. Even the 
very few persons who would assign to the famous naturalist a 
less solitary preeminence must admit that his ability was of 
the highest order.’’ Such an estimate of Darwin, recently ex- 
pressed by Professor Minot, is seldom presented in discussions 
of Darwinism. Those using this term must explain that they 
do not mean the origin of coral islands through subsidence of 
the ocean floor, or the overturning of the earth by worms, or the 
adaptations of plants to cross-fertilization, or even organic evo- 
lution, but that they have in mind natural and sexual selection 
and perhaps also pangenesis. The recent book by Professor 
Kellogg is a discussion of the various theories of evolution. 

The first chapter introduces the reader to the ‘‘ philosophic 
turmoil and wordy strife,’’ very little of which is said to have 
= found its way into current American literature. In the second 
chapter it is stated that the ‘‘millions of kinds of animals and 
plants can have had an origin in some one of but three ways; 
they have come into existence spontaneously, they have been 
specially created by some supernatural power, or they have de- 
scended one from the other in many-branching series by gradual 
transformation. There is absolutely no scientific evidence for 


either of the first two ways; . . . If such a summary disposal 
of the theories of spontaneous generation and divine creation 
is too repugnant to my readers, ... then my book and such’ 


readers had better immediately part company; we do not speak 
the same language.’’ 

There is little depth in such a statement. It will be generally 
conceded that existing animals have descended from the past, 

* Kellogg, V. L. Darwinism To-day. A discussion of present-day sci- 
entific criticism of the Darwinian selection theories, together with a 
brief account of the principal other proposed auxiliary and alternative 
theories of species-forming. New York, Henry Holt and Company, 1907. 
403 pp. $2.00. 

58 


No. 493] NOTES AND LITERATURE 59 


and that at some remote time one or many forms first appeared 
upon the earth. Some will say that they appeared spontaneously 
and others that they were a divine creation, just as present 
occurrences are regarded by some as spontaneous and by others 
as divinely ordained. However, that the debate should not be 
checked by philosophy, the author hastens to consider the vari- 
ous attacks on ‘‘Darwinism,’’ the defense, and finally other 
theories which may be substituted. His style is breezy, such 
as Englishmen describe as American, and New Englanders as 
Western. 

‘‘ Sexual selection is one of Darwin’s supporting theories which 
has nearly gone quite by the board.’’ In support of this Mayer’s 
convincing experiments with Callosamia promethea are fully 
described. ‘‘If there is any moth species in which the colors 
and general pattern of the male ought to be readily obvious to 
the female... it is this species.” Mayer found that the 
females did not prefer normal males to those from which the 
wings had been clipped, or to those on which the red-brown 
wings of the female had been fastened in place of their own 
black ones of very different shape. The author believes that a 
satisfactory explanation of sexual dimorphism is yet to be 
formulated. 

The importance of selection in producing mimicry in color 
patterns is accepted, though somewhat doubtfully. Professor 
Kellogg says of Basilarchia—‘‘But thanks to its perfectly 
mimicking color-pattern, it wings its deceitful way unmolested. 
There is huge usefulness here, and selection can well be the 
steadfast maintainer of the viceroy’s dissimulation.’’ The mar- 
ring of the resemblance by the dark streak across the hind 
wings is noted but not accounted for; the ‘‘over-refined’’ re- 
semblance of Kallima to a leaf is called ‘‘absurd.’’ The author 
leaves his reader to draw his own conclusions in regard to 
mimiery and many other problems. Thus Bumpus is cited to 
show that a storm destroys the physically defective sparrows, 
and Kellogg shows that a drought destroys the fit and the unfit 
fish. The reader must judge whether it is variation or ‘‘hard 
luck’? which usually brings destruction. 

Three theories alternative with selection are presented, namely, 
‘‘Lamarckism,’’ orthogenesis, and heterogenesis (mutation). 
Darwin is cited in favor of all three. Lamarck’s conception of 
evolution is ‘‘a great thought and a clear one,” buts it lacks 


60 THE AMERICAN NATURALIST [ Vou. XLII 


experimental support. Likewise for the theory of heterogenesis 
as capable of explaining species formation as a whole, the author 
finds an ‘‘extreme meagerness in quantity of the real scientific 
evidence.” He declares that no indubitable cases of species- 
forming or transforming have been observed. 

“The theories of orthogenesis of the general type exemplified 
by Eimer’s are directly in line with the spirit of modern bio- 
logical methods and investigations. They rest on the assumption 
that physico-chemical factors produce direct effects on the plas- 
tic organism, and that such effects . . . modify or control evo- 
lution.’’ Any tendency; such as is shown by Nägeli, to substitute 
a ‘‘mystie vital foree’’ for the ‘‘ physico-chemical factors’’ re- 
ceives the author’s severe censure; yet except as one emphasizes 
the complex and unknown internal factors rather than the 
simpler conditions of environment, these conceptions are not 
far apart. ‘‘Nageli believes that animals and plants would have 
developed about as they have, even had no struggle for existence 
taken place, and the climatic and geologic conditions been quite 
different from what they actually have been.’’ Much more could 
be said in favor of orthogenesis than Professor Kellogg records. 

In the concluding chapter it is stated that ‘‘ Darwinism, then, 
as the natural selection of the fit, the final arbiter in descent- 
control, stands unscathed, clear and high above the obscuring 
cloud of battle. . . . To my mind every theory of heterogenesis, 
of orthogenesis, or of modification by the transmission of acquired 
characters confesses itself ultimately subordinate to the natural 
selection theory.’’ Yet before closing, Professor Kellogg returns 
to a discussion of orthogenesis as ‘‘a determinate though not 
purposeful change.” | 

After each chapter there is an appendix containing consider- 
able citations from works on evolution. The volume should prove 
valuable to students; we hope that they will not lay it aside 
with the author’s remark ‘‘Kurz und gut, we are immensely 
unsettled.’’ 

Poth. 


The Effect of Environment upon Animals.—It is well known 
that if the pupe of certain butterflies, e: g., Vanessa or Pyra- 
meis, be subjected to extreme cold (0° to — 20° C.) many of the 
adults will be aberrant in color pattern. However, if they be 
subjected to extreme heat (42° to 46° C.) the same aberrations 


No. 493] NOTES AND LITERATURE 61 


will be produced. Less extreme heat (35° to 37°C.) gives 
aberrations differing from these. Opinions do not agree as to 
the reason why extreme heat and extreme cold produce the 
same results. M. von Linden considers it to be a ‘‘ pathological’’ 
phenomenon caused by tissue injury. Narecotizing and whirl- 
ing on a centrifugal machine cause similar effects. Fischer? 
argues with great force that this is not so. He believes it to 
be a ‘“‘normal’’ arrest of development, such as occurs during 
hibernation, pointing out, however, the difficulty of drawing a 
sharp line between normal and pathological physiology. Both 
Vanessa and Pyrameis are common in America. It would be 
well worth while to study critically the inheritance of these 
abnormalities. 

Salamandra maculosa is normally either viviparous or ovip- 
arous, producing a large number (up to 72), young. These 
young, when born, are larve. They live in water for some time, 
finally losing their gills and metamorphosing into land sala- 
manders. If, however, the female be deprived of water, she will 
give birth to a small number (2 to 7) of young which have 
already lost their gills. Kammerer?’ carried the experiment 
still farther and found that, even if the abnormally born females 
be given water, they give birth to young having reduced gills. 

Plate è has made a detailed study of the genus Cerion (land 
snails) of the Bahama Islands. Many local races or varieties 
were found. He believes these to be due to the modifying in- 
fluence of the environment, but gives no experimental evidence. 
Snails could easily be transplanted from one island to another 
in order to test this point. The Bahama Islands are so near 
to America that this problem should appeal especially to Ameri- 
ean students of evolution. 

FRANK E. LUTZ. 

1 Fischer, E. Zur Physiologie der Aberationen- und Varietaten-Bildung 
der Schmetterlinge. Archiv für Rassen- und Gesellschafts-Biologie, IV, 
6, November—December, 1907. 

merer, Paul. Die Nachkommen der spätgebornen Salamandra 
maculosa und dae friihgebornen Salamandra atra. Archiv fiir Entwick- 
lungsmechanik der Organismen, XXV, 1 and 2, December, 1907 
* Plate, C. Die Variabilität und die Artbildung nach dem Prinzip geo- 
graphischer Formenketten bei den Cerion-Landseht wecken der Bahama- 
Inseln. Archiv für Rassen- und Gesellschafts-Biologie, IV, 4 and 5, July- 
October, 1907. 


62 TUE AMERICAN NATURALIST [Von XLII 


THE PROTOZOA 


Some Recent Protozoa Literature.— Waves of special enthusiasm 
sweep over the domain of biology as of other sciences; each 
leaves its mark, passes on and is followed by others. At one 
time it was the ‘‘section cutters’’ at another the ‘‘finger bowl 
brigade,’’ at present it is genetics. Some investigators are 
independent enough to swim in quieter waters while some are 
so bold as to try to make an independent high-water mark long 
after the wave has passed. To the later group Hartmann and 
Prowazek must be assigned, for in a recent paper! they deal 
with the homologies of the centrosome, a problem which has 
never been solved and one that can not be regarded as obsolete, 
but which is no longer on the wave of biological enthusiasm. 

Nor is the point of approach at all novel. They see in the 
nucleus and centrosome of the higher cell types only the remi- 
niscence of a dual condition in protozoa. To be sure, they bring 
to bear a great fund of recently published observations, more 
particularly on protozoan cell structures, and they see in the 
metazoan nucleus and centrosome the outcome of dimorphic nu- 
clei in these primitive animals. The two nuclei of the hypothet- 
ical ancestral form are not of the type suggested by Schaudinn in 
the early advocacy of this same theory (Ameba binucleata), but 
of the type seen in Trypanosoma, where trophonucleus and 
kinetonucleus are persistent morphological elements of the cell. 
They believe that the same dual arrangement is present in other 
protozoa; in some the kinetonucleus is reduced to a mere granule 
outside of the normal cell nucleus (as in the Centralkorn of the 
Heliozoa) ; in others the two nuclei are united to form an ‘‘am- 
phinucleus,’’ the one encased within the other as in the typical 
centronucleus. Here is the only really novel point in their 
discussion, and this can not be accepted, for to assign to the 
division center in a nucleus of the Euglena type the rôle of 
an independent nucleus is a reductio ad absurdum. The authors 
use a considerable area of printed matter to prove that these 
kinetoplasmic structures in protozoa are homologous with the 
centrosomes of higher forms, a point of view generally accepted 
more than a decade ago; and certainly nothing new is gained 

1 Hartmann and Prowazek. Blepharoplast, Karyosom und Centrosom. 
Arch. f. Prot., X, 2-3 


No. 493] NOTES AND LITERATURE 63 


by calling these division centers ‘‘nuclei.’’ The one feature 
in support of this view is the presence of chromatoid material 
about the blepharoplast in Trypanosoma and in Parameeba, but 
even the truth of this is not generally accepted, Schaudinn’s 
observations not having had sufficient confirmation to warrant 
universal acceptance. The authors’ statement that chromatin 
material is likewise present in the great sphere of Noctiluca is 
not true. On the whole this conception of blepharoplast, karyo- 
some and centrosome gives an inadequate summary of the stri- 
king recent advances in protozoan morphology and leaves the 
problem of the origin of the metazoan centrosome very much 
as it was ten years ago. 

The pioneer work of Schaudinn’s upon which this conception 
of Hartmann and Prowazek’s is based has not been fully and 
satisfactorily confirmed, while much of it has been denied. 
Novy, for example, has continually fought against the double 
intra- and extra-cellular life of Trypanosoma noctuæ and now 
Moore and Breinl,? working with different kinds of Trypano- 
soma, find that the nuclei of 7. gambiense, T. brucei and T. 
equinum all conform to the centronucleus type and that the 
blepharoplast or kinetonucleus (Woodcock) arises in the latent 
bodies by halving of the intra-nuclear division center and with- 
out any accompanying chromatin such as Schaudinn described 
in the case of T. noctuw. Passing over the fact that the present 
authors somewhat stultify themselves on the perfection of their 
technique and give an ungenerous blanket criticism of all others 
who have worked upon the morphology of trypanosomes, it must 
be admitted that their criticism is to a certain extent justified, 
for the majority of observers have made too free use of the dry 
smear method. The so-called chromosomes of the trypano- 
somes, for example (not chromosomes at all in the strict sense), 
are interpreted by Moore and Breinl as irregular masses of 
chromatin which may assume any form under the rough proc- | 
esses of the dry method of fixation. This may or may not be 
true, but at any rate the figures given by the English authors 
and representing the finer structures of these nuclei do not 
inspire confidence in the methods which they themselves advo- 
cate, although they are, indeed, well tried and recognized 
methods. 

2 Moore and Breinl. Cytology of the Trypanosomes. Annals of the 
Liverpool School of Tropical Medicine, 1, No. 3. 


64 THE AMERICAN NATURALIST [Vou. XLII 


Apart from this question of technique, upon which the last 
word is not yet given, Moore and Breinl bring forward evidence 
which throws a new light on the life history of T. gambiense, the 
cause of sleeping sickness. They find a phase in the life his- 
tory where the nucleus, surrounded by a small bit of proto- 
plasm, is left over after the bulk of the trypanosome has degener- 
ated. This nucleated bit, which they name the ‘‘latent body,’’ 
is stored up in the spleen and bone marrow of the experimental 
animal (rat), ultimately reappearing in the circulation where 
a new, young trypanosome arises from it. They find no evi- 
dence of trimorphie differentiation which Schaudinn first de- 
scribed for T. noctue, but they call attention to the fact that 
a complete series of sizes of trypanosoma may be selected, and 
claim that the indifferent, male, and female, forms are only 
arbitrarily chosen individuals from such a series. 

Another interpretation is given to the trypanosomes with long 
chromatin bars such as Prowazek in the ease of T. lewisi re- 
garded as male forms. The English observers introduce a new 
hypothesis to account for this, viz., that it represents a type of 
autogamous conjugation. The bar is of kinoplasmic material 
growing out from the blepharoplast to the nucleus, where a 
portion of its substance, as they believe, unites with the nucleus. 
The suggestion is ingenious and, in view of the constantly grow- 
ing evidence in favor of autogamy in other kinds of protozoa 
(Entameeba, Actinospherium, Ameba proteus, ete.), must be 
taken into account. 

On a priori grounds it would certainly seem that if conju- 
gation among trypanosomes is a normal part of the life history, 
and there is no reason to believe it absent, it would be more 
frequently observed and there would be no uncertainty about it. 
Its infrequeney and the doubt existing in regard to the observa- 
tions that have already been made lead us to suspect that conju- 
gation of some obscure type occurs here. In flagellated protozoa 
where conjugation of the ordinary type is characteristic, the 
periodicity of conjugation is one of the most noteworthy fea- 
tures. This is well illustrated in a timely article by C. Clifford 
Dobell on the life history of a simple Peranema-like flagellate 
which he names Copromonas subtilis” The flagellate is a com- 

? Dobell, C. Clifford. The Structure and Life History of Copromonas 
subtilis nov. gen. et nov. sp., a Contribution to our Knowledge of the Fla- 
gellata. Q. J. M. S., No. 205, 1908. 


No. 493] NOTES AND LITERATURE 65 


. mon parasite of the rectum of frogs and toads and grows readily, 
the author observes, in rectal contents with normal salt. Con- 
jugation between similar organisms (isogametes) occurs from 
the seventh to the ninth day of such a culture, the result being 
either an encysted form (permanent cyst) or a motile form 
which reproduces by division for several generations and then 
encysts. 
` The trypanosomes evidently present no such simple life his- 
tory as this which Dobell describes and, although accumulating 
evidence makes it probable that all stages are confined to the 
single host in the greater number of cases at least, every de- 
scription of conjugation thus far published is so fantastic as to 
arouse suspicion. What is true of trypanosomes is even more 
characteristic of spirochetes, a field of research so difficult that 
very few have had the hardihood to publish accounts of con- 
jugation, and needless to say none that has been published is 
acceptable. The latest on Spirocheta is a paper by H. B. 
Fantham on the relatively large spirochete of the oyster and 
clam. This Spirocheta balbianii, which was monographed by 
Perrin a couple of years ago, is interesting in having a central 
helix of chromatin which is spirally wound, and upon which 
larger granules of chromatin are suspended at intervals. This 
represents an intermediate condition, so far as the nucleus is 
concerned, between the isolated granules of chromatin in bac- 
teria and in certain forms of Spirocheta (e. g., S.:obermeiert), 
and the formed nuclei of higher types of protozoa. Reprodue- 
tion both of this form and of S. anodonte is by longitudinal and 
occasionally transverse division, both types occurring according 
to the author. Conjugation in no form was observed. Like 
the majority. of recent writers on the spirochetes, Fantham pro- 
poses a new group for them intermediate between the protozoa 
and the bacteria. He suggests that they be made a new ‘“‘class”’ 
of organisms under the name ‘‘Spirochetacea.’’ Such innova- 
tions, however, can do no good and it is far better not to further 
confuse an already mixed up classification. When the full life 
history of the genus (or genera) of Spirocheta is known it will 
be time enough to change the classification. 

These flagellates are not the only forms of protozoa over 

‘Fantham, H. B. Spirocheta (Trypanosoma) balbianii (Certes) and 
‘Spirocheta anodonte (Keysselitz). Their Movements, Structure and Affini- 
ties. Q. J. M. S, No. 205, 1908. : : 


- 66 THE AMERICAN NATURALIST [Vou. XLII 


which there is much discussion and controversy at the present - 
time. The rhizopods offer quite as extensive a field for diver- 
gent opinions and here again it is mainly in connection with 
the parasitic types. The lfe histories of the ordinary forms 
are being slowly established and with this basis the parasitic 
forms should be comparatively simple to work out. The one 
remaining important step to be made in working out the life 
history of the common rhizopod Arcella vulgaris has quite re- 
cently been taken by W. Elpetiewsky,® and it is fitting that it 
should have been made in Hertwig’s laboratory, where the first 
important steps were taken. The author finds that gametic 
nuclei are formed from the distributed chromidia in the way 
described by Schaudinn for Centropyxis, and by Schaudinn and 
Lister for Polystomella. Macrogametes and microgametes are 
formed and conjugation of two such anisogamous swarmers was 
followed step by step. He found furthermore, that Arcella re- 
produces also by the formation of pseudopodiospores, and that 
these develop fine heliozoa-like radiating pseudopodia, upon the 
ends of which they roll about for a period of from two to three 
hours. This observation is interesting in the light of the pos- 
sible origin of the lobose rhizopods from the heliozoa. 

It is not quite so simple a matter to accept the latest work on 
the parasitic rhizopods and we entirely disagree with Prowazek ° 
in his conception of the so-called group Chlamydozoa. In this 
proposed new group of protozoa which he would place inter- 
mediate between the protozoa and the bacteria, Prowazek places 
the majority of the recently contested forms of disease-produ- 
cing organisms. The disputed organisms of variola, vaccinia, 
searlet fever, trachoma, rabies, Molluscum contagiosum, and | 
some others of less importance are all grouped together here 
apparently without regard to their morphology or effects upon 
the host. All of these organisms are regarded as extremely small 
cell parasites which are made conspicuous by reason of a more 
or less thick secretion of nuclear material about them, the name 
of the proposed group being based upon this characteristic 
(xAapnvs—mantle). 

In this supposition the author takes a great deal for granted 
and begs two very important questions, first, that the inclusions 

sW, Elpetiewsky. Zur Fortpflanzung von Arcella vulgaris Ehr. in 
Arch. f. Prot., X, No. 2-3, 1907. 

èS. Prowazek. Chlamydozoa. In Arch. f. Prot., X, No. 2-3, 1907. 


No. 493] NOTES AND LITERATURE 67 


are organisms, and second, if organisms, that the bulk of their 
substance is to be traced to nuclear secretions. The limits of the 
present reference will not permit an extensive analysis of Pro- 
wazek’s different assumptions, but one or two matters may be 
pointed out as showing his method of treatment, and incidentally 
his ignorance or, possibly, disregard, of careful work of others. 
The organism of rabies, for example, exists, as do all rhizopod 
protozoa in many different sizes, and one form of the organism 
is extremely minute. This small phase is characteristic of the 
so-called ‘‘fixed virus’? and has been entirely overlooked by 
Prowazek despite the accurate and detailed work of Dr. A. W. 
Williams and others. In another phase the organism is quite 
large and characteristically amceboid in form. Prowazek finds 
none of these larger forms in centrifuged virus and coneludes 
that the intra-cellular phase is absent in the virus thus treated, 
and since he failed to see these forms in the fixed virus he 
further concludes that the bulk of the Negri body in rabies must 
be a nuclear secretion and that the organisms are the minute 
brightly staining points (chromatin) of the larger forms which 
are actually present in the fixed virus and in centrifuged virus, 
but invisible. In this conclusion he shows not only a total dis- 
regard for what other competent workers have done, but a sur- 
prising ignorance of the actual structure of the Negri body. 

Apart from special criticisms which might be carried out for 
each of the diseases mentioned, the general criticism may be 
made that it is not good zoology to create a group in classifiea- 
tion while there is still some doubt as to the organisms being 
living things; and it is not good cytology to assume an en- 
tirely new funetion (of specific secretions) in various cells in 
response to such questionable organisms. The present critic 
believes, indeed, that these questionable structures are organisms, 
and organisms belonging to the rhizopod group of protozoa, but 
not to any group with the characteristics of the proposed 
**Chlamydozoa.’’ 

G N. C. 


EXPERIMENTAL ZOOLOGY 


The Determination of Sex in Frogs.—Few results in experi- 
mental biology have been more puzzling than those involving the 
question of the determination of the sex of the frog. The earliest 


68 THE AMERICAN NATURALIST (Vou. XLII 


observations—those of Born—seemed to indicate that the food 
given to the young tadpoles determined the sex of the frog. 
Yung also obtained about 70 per cent. of females when his 
tadpoles were well fed. Balbiani and Henneguy have stated 
that tadpoles fed on egg-yolk produced more females than those 
fed on a vegetarian diet. On the other hand, Cuénot obtained 
no such results, and the recent careful and extensive experiments 
of Miss King have shown clearly for the toad that the nutrition 
of the tadpole has no influence on the sex of the adult. De- 
spite the fact that these recent results go far towards showing 
that sex is not determined or even altered by food relations, a 
curious disproportion of the sexes in frogs has been noted by 
several observers. The recent valuable experiments of Richard 
Hertwig do not, in the opinion of the reviewer, bear out the 
interpretation that Hertwig has placed upon them. Neverthe- 
less, his methods give promise, if further extended, of throwing 
light on the problem. 

In Hertwig’s first contribution to the subject published in 
1906 he suggested that sex is determined by the condition of 
ripeness of the egg at the moment of fertilization. This view 
is not new, and Hertwig’s attempt to connect his view with the 
ratio of nucleus to cell-plasm of the egg at different periods of 
its maturation can hardly be looked upon favorably, since in the 
frog’s egg the nucleus as such has already disappeared when the 
egg leaves the ovary. The chromosomes are thereafter arranged 
on the equatorial plate of the first polar spindle. It is, how- 
ever, during this period that the degree of ripening is supposed 
to determine the sex of the egg. However unsatisfactory this 
specific suggestion of Hertwig may now appear, the possibility 
must still be granted that in some way the degree of maturity 
of the egg may have an influence on sex-determination. Hert- 
wig interpreted his experiments to mean that at first the egg 
tends to produce males, then during the middle phases of its 
ripening it tends to produce females, and finally during its 
later phases again its tendency is towards male production. It 
is not our purpose to discuss in detail this interpretation, but 
it may be stated that Hertwig’s experiments fell far short of 
proving his hypothesis. 

In Hertwig’s second paper,! to which we wish more especially 

1 Hertwig, R. Weitere Untersuchungen ueber das Sexualitätsproblem. 
Verh. Deutsch. Zool. Gesell., 1907. 


No. 493] NOTES AND LITERATURE 69 


to call attention, he also brings forward the same hypothesis and 
attempts to explain certain incongruities of the two series by 
other suggestions. It will be noticed that while the ‘‘older’’ 
eggs give an enormously high percentage of males, those first 
fertilized also give an excess of males or at least equal num- 
bers of the two sexes. There is no middle register in which 
females are in excess. 

Hertwig’s principal results are shown in the accompanying 
table. The eggs of three females, 1, 6, and 10, were fertilized 
at four different intervals (I, II, III, IV) of several hours apart 
(6, 18, 30, ete.) ; the percentages show in each case how many 
males developed to each 100 females—the actual number of indi- 
viduals employed standing above the percentages. The stri- 
king fact shown by the table is the high percentage of males 
throughout, but especially towards the end. of each series, where 
in one case there were 129 males to 17 females. 

I H III IV 
ie sig aon OO 
1. 849: 47g 659: 77g 1569: 1948 79: 48¢ 
141¢ 1194 12 685¢ 


= 56 e 
6. 649: 61g 1019: 139g 1159: 169g 
954 1374 147% 


NE oo ime BE se oS 
10. 559: 52g 1489: 87g 719: 70g 179: 129g 
100¢ 59% 100% 759% 


The results leave little doubt that there is something in this 
series that stands for maleness. A number of possibilities be- 
sides the one adopted by Hertwig will suggest themselves. There 
is, moreover, one vital weakness in the experiment as carried out, 
for which, unfortunately, there is no control—different males 
were used, apparently, at least for the last fertilization, and the 
percentage of male-producing sperm present in these males was 
not determined. Without this control the experiment is seriously 
defective. Hertwig himself has realized this deficiency and has 
carried out one successful experiment in which the eggs of one 
female—separated into lots—were fertilized by different males. 
The results are not convincing, as the following statement shows. 

The eggs of a female from a locality (Lochausen, indicated 
by L in the table), where the season was nearly at its end, were 
separated into six lots. Three of these were fertilized by sperm 


70 THE AMERICAN NATURALIST [ Von. XLII 


from three males of the same locality (indicated by Ņ, l, l, in 
the table), and the other three were fertilized by sperm of 
three males from another locality (Schleissheim, —S in dia- 
gram). The converse experiment was also carried out. The 
results are given in the next table, in which the double sign 
2 g indicates that the sexual organs were in an indifferent con- 
dition. It will be observed that a very large number of indi- 
viduals are referred to this category. Hertwig states that in 
those cultures that developed best there was a decided excess of 
males—more than of indifferent forms. On the other hand, the * 
poor cultures contained females almost exclusively, fewer in- 
different forms and no males. 
v s P 
L 29g: 319 99d: 539 80g: 7798 
8. Soa" © 659 t 77g: 7398 
E E 
L. 176g : 1569¢ 
S. 108 : 7598 93, 5989 : 659g, 119 


Hertwig thinks that the results show that the sperm has a dis- 
tinct influence on sex-determination. He suggests that in the 
present case the eggs were nearly in a condition of equilibrium 
so that a slight influence on the part of the male sufficed to turn 
the scales. He adds that it is thinkable that as a rule the eggs 
at the time of normal fertilization have their sex so positively 
determined that the relatively small influence of the male has 
no influence. It will be noted, however, that in Hertwig’s own 
experiment the condition of the two females selected was very 
different, yet there is a surprising similarity in the results pro- 
duced when the males that fertilized the eggs are considered. 

The experimental results are not sufficient to give any posi- 
tive light on the question, but the method that Hertwig has 
employed in the last experiment is one that promises to give 
an answer to the question whether the egg or the sperm deter- 
mines the sex in the frog. 

If one may hazard a guess, the results of Hertwig’s experi- 
ments seem to show that the male is responsible for sex-determi- 
nation. Since normally all the eggs are fertilized it can not be 
assumed that, if they are of two sexes, those of one sex are 
preponderatingly injured or killed by the cold of winter. In 
regard to the sperm, however, it is possible that more of one kind, 


No. 493] NOTES AND LITERATURE 71 


if two kinds exist, are injured or that internal processes may lead 
to the production of more functional sperm of one sex. These 
factors may differ in different individuals or be characteristic of 
different races or regions. The importance of settling this ques- 
tion and the ease with which the experiment can be carried out 
with the simplest possible apparatus ought to lead many natu- 
ralists to repeat the experiment in different localities and with 
different species. The only difficulty arises from the mortality 
of the tadpoles; for they must be kept until the time of meta- 
morphosis (which, however, for the wood frog, the toad and for 
some of the tree frogs takes place as early as June of the same 
year). By keeping the tadpoles in running water, or by chan- 
ging the water in the dishes every day, success is assured. 


ANATOMY 


Wiedersheim’s Comparative Anatomy. The various forms and 
editions of this work have been for two decades, we believe, the 
most used and useful text-books upon the comparative anatomy 
of vertebrates. In the ten years since the publication of the 
second English edition, three progressively larger German edi- 
tions have appeared, and the book became so large that Wieders- 
heim published a résumé entitled ‘An Introduction to Com- 
parative Anatomy.’’ The third English edition is, in both size 
and substance, a compromise between the second English and 
the large German editions. The text proper occupies one hun- 
dred and ten pages more than in the second edition. This is 
due partly to the addition of new matter and partly to the use 
of uniform type in the text, instead of printing in smaller type 
the matter assumed to be less worthy of the student’s attention. 
This change has improved the appearance of the book and the 
inerease in size has been partly counterbalanced by printing 
more compactly and in smaller type the much extended and 
useful bibliography. 

New facts have been incorporated, usually and unfortunately 
without recasting, but the sections upon the skin, skull, brain- 

1 Comparative Anatomy of Vertebrates. Adapted from the German of 
Dr. R. Wiedersheim, by W. N. Parker. Third edition, founded on the sixth 
German edition. 576 pp., 372 figures. The Macmillan Company, 1907. 


72 THE AMERICAN NATURALIST [ Vou. XLII 


membranes and ‘‘adrenals’’ have been essentially rewritten. As 
a result, the book is improved by many small increments as well 
as by the new treatment of a few subjects. 

Among these is the interesting physiological difference be- 
tween the lungs of birds and of mammals, now properly noted 
for the first time. In mammals during inspiration the lung 
expands and draws into its blind terminal respiratory chambers 
a mixture of fresh and residual air. The residual air greatly 
dilutes the oxygen which comes in contact with the absorbing 
blood vessels, and also prevents the carbon dioxide from being 
expired directly. In birds the lung is a network of anastomos- 
ing tubes which are not expansile. Fresh air is drawn through 
these tubes by the expansion of the air sacs, which are non- 
respiratory terminal prolongations of the lung. The lung of 
the bird may, in a sense, be compared with the respiratory 
bronchioles of mammals, the mammalian alveoli corresponding 
with the avian air sacs. Thus the lung of birds is peculiarly 
adapted for the rapid oxidation correlated with the. require- 
ments of flight and with a high body temperature. Other ad- 
ditions of this sort contribute to the value of this edition. 

. W. WILLIAMS. 
(No. 492 was issued January 23, 1908.) 


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VOL. XLII, NO. 494 


~ 
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tool 
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Zoological Progress. 
Notes and Literature: Heredity—The Possibility of Inheritance through 


AOE 


AMERICAN 
NATURALIS 


A MONTHLY JOURNAL 
DEVOTED TO THE NATURAL SCIENCES 
IN THEIR WIDEST SENSE 


CONTENTS 


The Law of Geminate Species. í President DAVID STARR JORDAN 

Fasciations of Known Causation . . ‘ ` : Dr. HENRI HUS 

The Aggregate Origination of Parasitic Plants. Dr. CHARLES A. WHITE 

The Evolution of the Tertiary Mammals and the pasese of their 
Migrations. 


Professor CHARLES DEPÉRET 
. Professor G. H. PARKER 


the Placental Circulation instead of through Germ Cells, F. T. L. Jnverte- 


xperi 
ments in Transplanting Limbs, and their Bearing upon the Problem of 
Dinig of Nerves, A. 


THE SCIENCE PRESS 


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THE 


AMERICAN NATURALIST 


Voi. XLII February, 1908 No. 494 


THE LAW OF GEMINATE SPECIES 


PRESIDENT DAVID STARR JORDAN 


STANFORD UNIVERSITY 


Ix ‘‘Evolution and Animal Life,” by Jordan and 
Kellogg (page 120), the following words are used: 


“ Given any species, in any region, the nearest related species is not 
to be found in the same region nor in a remote region, but in a neigh- 
boring district separated from the first by a barrier of some sort or at 
least by a belt of country, the breadth of which gives the effect of 
a barrier.” 


Substituting the word ‘‘kind’’ for species in the above 
sentence, thus including geographical subspecies, or nas- 
cent species, as well as species clearly definable as such, 
Dr. J. A. Allen accepts this proposition as representing 
a general fact in the relations of the higher animals. To 
this generalization Dr. Allen, in a late number of Science, 
gives the name of ‘‘Jordan’s Law.’’ The present writer 
makes no claim to the discovery of this law. The lan- 
guage above quoted is his, but the idea is familiar to all 
students of geographical distribution and goes back to 
the master in that field, Moritz Wagner. 

This law rests on the fact that the minor differences 
which separate species and subspecies among animals are 
due to some form of segregation or isolation. By some 
barrier or other the members of one group are prevented 
from interbreeding with those of another minor group 
or with the mass of the species. As a result, local pecul- 
iarities arise. ‘‘Migration holds species true, localiza- 

73 


74 THE AMERICAN NATURALIST (Vou. XLII 


tion lets them slip,’’ or rather leaves them behind in the 
process of modification. The peculiarities of the par- 
ents in an isolated group become intensified by in and in 
breeding. They become modified in a continuous direc- 
tion by the selection induced by the local environment. 
They are possibly changed in one way or another by 
germinal reactions from impact of environment. At last 
a new form is recognizable. And this new form is never 
coincident in its range with the parent species, or with 
any other closely cognate form, neither is it likely to be 
in some remote part of the earth. Whenever the range 
of two such forms overlaps in any degree, the fact seems 
to find an explanation in reinvasion on the part of one 
or both of the forms. The obvious immediate element 
in the formation of species is, therefore, isolation, and 
behind these are the factors of heredity, of variation, of 
selection, and others as yet more or less hypothetical in- 
volved in the effect of impact of environment on the germ 
cells themselves. The formation of breeds of sheep as 
noted by Jordan and Kellogg (p. 82), seems exactly par- 
allel with the formation of species in nature. In like man- 
ner, the occasional development of breeds arising from the 
peculiarities of individuals is possibly parallel with the 
‘‘mutations’’ of the evening primrose. Such breeds are 
the Ancon sheep in Connecticut and the blue-cap Wensley- 
dale’ sheep in Australia. The ontogenetic species— 
groups in which many individuals are simultaneously 
modified in the same way by like conditions of food or 
climate—show no permanence in heredity. Such forms, 
however strongly marked, should, therefore, have no per- 
manent place in taxonomy. The recent studies of Mr. 
Beebe on the effects of moist air in giving dusky colors 
to birds serve to illustrate the impermanence of the groups 
or subspecies characterized by dark shades of color de- 
veloped in regions of heavy rainfall. 

It may also be noted in passing that one cause of the 

*Blue Cap, a ram of Leicester-Teeswater parentage, having a blue 


shade on his head, was the progenitor of a breed having this peculiarity, 
known as the Wensleydale, in Australia. 


No. 494] THE LAW OF GEMINATE SPECIES 75 


potency of artificial selection among domesticated animals 
or cultivated plants is that such selection is always 
accompanied by segregation. The latter is taken for 
granted in discussions of this topic and hence its existence 
as a factor is usually overlooked. While poultry or 
pigeons can be rapidly and radically changed by arti- 
ficial selection, in isolation, no process of selection without 
isolation is likely to have any permanent result. For 
example, we know no way of improving the breed of 
salmon, because the salmon we have selected for repro- 
duction must be turned loose in the sea, where they are 
at once lost in the mass. 

New forms of gold-fish and carp can be made easily 
in domestication, because these fishes can be kept in 
aquaria or in little ponds, but new forms of mackerel or 
herring are beyond the control of man and the species 
actually existing have been of the slowest creation, their 
origin lost in geologic times. 

One of the most interesting features of ‘‘ Jordan’s law’’ 
is the existence of what I may term geminate species— 
twin species—each one representing the other on oppo- 
site sides of some form of barrier. In a general way, 
these geminate species agree with each other in all the 
respects which usually distinguish species within the 
same genus. They differ in minor regards, characters 
which we may safely suppose to be of later origin than 
the ordinary specific characters in their group. TIllustra- 
tions of geminate species of birds, of mammals, of fishes, 
of reptiles, of snails, or of insects, are well known to all 
students of these groups, and illustrations may be found 
at every hand. 

Each island of the West Indies, which is well separated 
from its neighbors, has its own form of golden warbler. 
Each island in the East Indies has its geminate forms of 
reptiles or fishes. Each island of the Hawaiian group 
has its own representative of each one of the types or 
genera of Drepanide. Each group of rookeries in Ber- 
ing Sea has its own species of fur seal. 

One of the most remarkable cases of geminate species 


T6. THE AMERICAN NATURALIST [Vor. XLII 
is that of the fishes on the two sides of the isthmus of 
Panama. Living under essentially the same conditions, 
but separated since the end of the Miocene Period by the 
rise of the isthmus, we find species after species which 
has been thus split into two. These geminate species, a 
hundred or more pairs in number, were at first regarded 
as identical on the two shores of the isthmus. Later one 
pair after another was split into recognizable species. 
The latest authority on the subject, Mr. C. T. Regan, 
seems to doubt if any species of shore fishes are actually 
identical on the two sides of the isthmus. 

To make this clear, though at the risk of being tedious, 
I give below a partial list of these geminate species about 
the isthmus of Panama: 


Atlantic Coast 
Harengula humeralis 


Centropomus pedimacula 
Centropomus affinis 
Epinephelus adscensionis 
Alphestes afer 
Dermatolepis inermis 
Hypoplectrus unicolor 
Lutianus cyanopterus 


Hemulon parra 
Hemulon schrancki 
Anisotremus suriamensis 
Anisotremus virginicus 


Encinostomus pseudogula 

Kyphosus incisor 

Isopisthus parvipinnis 
ebris microps 

Larimus fasciatus 


Pacific Coast 
Harengula thrissina 
Clupanodon libertatis 


Centropomus ensiferus 
Epinephelus analogus 
Alphestes multiguttatus 
Dermatolepis punctatus 
Hypoplectrus lamprurus 
Lutianus novemfasciatus 
Lutianus argentiventris 
Lutianus colorado 
Lutianus guttatus 
Hemulon sexfasciatum 


Anisotremus interruptus 
Anisotremus tæniatus 
Conodon serrifer 
Pomadasis branicki 
Calamus taurinus 
Xystæma simillimum 
Encinostomus dowi 
Kyphosus analogus 
Isopisthus remifer 
Nebris zestus 
Larimus pacificus 


No. 494] 


Atlantic Coast 
Odontoscion .dentex 
Corvula sialis 
Bairdiella vere-crucis 
Micropogon furnieri 
Umbrina broussoneti 
Menticirrhus littoralis 
Eques acuminatus 


THE LAW OF GEMINATE SPECIES 


Pacific Coast 
Odontoscion xanthops 
Corvula macrops 
Bairdiella armata 
Micropogon ectenes 
Umbrina xanti 
Menticirrhus elongatus 
Eques viola 


This list may be greatly extended, but the series noted 
will illustrate the point in question. Whenever a dis- 
tinct and sharply. defined barrier exists, geminate or 
twin species may be found on the two sides of it, unless, 
as sometimes happens, the species has failed to maintain 
itself on one side of the barrier. So far as Panama is 
concerned, we have evidence that the barrier was raised 
near the end of Miocene time with no trace of subsequent 
depression. We can thus form some estimate of the age 
of separation in at least a small number of closely related 
species. In this and similar cases it is not possible to con- 
ceive of the formation of these species by sudden muta- 
tion, or that they would retain their separate existence 
were the element of segregation removed. While segre- 
gation or isolation is not a force, and perhaps not strictly 
a cause in species formation, it is a factor which appar- 
ently can never be absent, if the species retains its inde- 
pendent existence. 

There is no doubt that the distribution of higher ani- 
mals in general is in accord with ‘‘Jordan’s Law.” Ex- 
amples by the thousand come up from every hand. If we 
had a hundredth part of the amount of available evidence 
in support of mutation theories, these theories would pass 
from the realm of hypothesis into that of fact. But the 
application of this law or rule to plants and to one-celled 
animals has been questioned. So far as rhizopods are 
concerned, Dr. Kofoid finds that the species are in general 
sharply defined and of the widest distribution in the sea, 
so that we can hardly state laws as defining their geo- 
graphical distribution. To these minute floating animals, 
the sea scarcely offers barriers at all, and the recognized 
species do not seem to be products of geographical iso- 


78 THE AMERICAN NATURALIST (Vog XLII 


lation. Doubtless these species in duration and in nature 
correspond more nearly to genera or families of higher 
animals than to actual species. Perhaps minor specific 
differences such as we note among arthropods or verte- 
brates are intangible or non-existent. The effects of iso- 
lation may be tangible only among forms which possess 
more varied relations with their environment. 

The application of this law to plants has also been 
denied. But geminate species are just as common in 
botany as in zoology, and the effects of isolation in species- 
forming are just as distinct. The law is just as patent 
in the one case as in the other. It is merely obscured by 
other laws or conditions which obtain among plants. 

In the nature of things, most physical barriers are more 
easily crossed by plants than by animals. The possibili- 
ties of reinvasion are thus doubtless much increased. The 
plant is limited by climate, rainfall, nature of soil, and the 
Same species is likely to occupy all suitable locations 
within a large area. Animals are more mobile than plants 
within their range, a fact which tends to keep the in- 
terbreeding masses more uniform. In the struggle for 
existence, the plant is pitted against its environment. 
Whether a plant survives or not depends not much on 
the nature of the seed, but mainly on its relation to the 
spot on which it falls. There is little selection within the 
species due to the choice of one individual as against 
another. This can only happen where plants are over- 
crowded, and there the survival is mainly that of the 
seed whose roots run deepest. There is little room for 
struggle between closely related species. Each individual 
grows—if it can—on the spot where it falls. The vari- 
ations among plants are great, but these variations are 
mostly lost unless reinforced by segregation. There is 
no likelihood of the survival of DeVries’ mutants of the 
evening primrose if these forms are left free to mix in 
the same field. 

Among plants we often notice the fact—rare though 
not unknown among animals—of numerous species of the 
same genus occupying the same area. In some cases these 


No. 494] THE LAW OF GEMINATE SPECIES 79 


species are closely related, suggesting mutants, and in 
other cases the relation indicates the existence of hybrids. 
In California, for example, there are in the same general 
region many species of Lupinus, of Calochortus, of Ceano- 
thus, of Arctostaphylos, of Eschscholtzia, of Godetia, of 
@Œnothera, and Opuntia. Eucalyptus, Acacia and Epa- 
cris in Australia are examples even more striking. But 
I have never seen very closely related or geminate forms 
in any of these genera actually growing together. TI sus- 
pect that they do so sometimes and that the explanation 
is found in reinvasion. But ‘‘growing together’’ is an 
indefinite statement as applied to plants. The elder, the 
alder and the madroño (arbutus) abound in the Santa 
Clara Valley. But no one ever saw any two of these 
trees standing side by side. Each has its limitations, as 
to soil and moisture. 

Setting aside these genera which are represented by 
many species in a limited area, and among which muta- 
tion and hybridism may be conceivably factors in species- 
forming, we find the law of geminate species applying to 
plants as well as to animals. Crossing the temperate zone 
anywhere on east and west lines, we find species after 
species replaced across the barriers by closely related 
forms. Illustrations may be taken anywhere among the 
higher plants—equally well, no doubt, among lower ones. 
Many genera are local in their distribution, monotypie— 
with a single species, the origin of which can not be traced. 
But many other genera belt the earth or come very near 
doing so, each form or species being geminate as related 
` to its next neighbor. This fact is illustrated in Rubus, 
Alnus, Sambucus, Platanus, Fagus, Veratrum, Symplo- 
carpus, Symphoricarpus, Castanea, Quercus, Pinus, 
Tsuga, Acer, Rhus, Pyrus, Prunus, Lonicera, Ranuncu- 
lus, Trientalis, Lilium, Trillium, Veronica, Aquilegia, 
Gentiana, Viola, Epilobium, Pteris, Mimulus, Trifolium, 
Solidago, Aster. All these genera and many others fur- 
nish an abundance of examples. 

We may, therefore, say that with plants as well as ani- 
mals geminate species as above defined owe their dis- 


80 THE AMERICAN NATURALIST [Vou. XLII 


tinctness to some form of isolation or segregation, and 
that, broadly speaking, with occasional exceptions, given 
any form of animal or plant in any region, the nearest 
related form is not to be found in the same region nor 
in a remote region, but in a neighboring region, separated 
from the first by a barrier of some sort, not freely 
traversable. 

A law, that is, an observed relation of cause and effect 
is not invalidated by the presence of other effects due 
to other causes, in the same environment. The actual 
conditions in nature are everywhere not products of single 
and simple forces, but résultants of many causative in- 
fluences, often operative through the long course of the 
ages. 

It may be urged that these geminate groups or forms 
are not true species, because they often intergrade one 
into another, and they would probably be lost by inter- 
mingling if the barriers were removed. It is sometimes 
claimed that only physiological tests of species can be 
trusted, as true species will not blend and their hybrids, 
if formed, will be sterile. All this is purely hypothetical 
and impracticable to the systematic zoologist, and not 
of much value to the botanist. Closely related species 
can usually be readily crossed. As the relation becomes 
less close, partial sterility of all grades and then total 
sterility appear. 

Species as we find them in nature are real species if 
that term has any definition. And real species have, as 
a rule, indefinite boundaries, shading off into subspe- 
cies, geminate species, ontogenetic forms and the like. 
And if we are to understand the significance of nature, 
we have to describe these facts and relations as they 
actually are. Then we have to find out what changes we 
can work in individuals and in species by such alterations 
of conditions as experiment can give. 

We do not know actually any species of animal or plant 
until we know all changes that would take place in its 
individuals under all conditions of environment. 


FASCIATIONS OF KNOWN CAUSATION 


DR. HENRI HUS 


MISSOURI BOTANICAL GARDEN 


Amone plants, whether in the garden or in the field, 
individuals occur with greater or less frequency, which, 
because they exhibit a striking departure from the accus- 
tomed form, attract immediate attention. To denote such 
abnormal forms, the term ‘‘teratological’’ is used. Tera- 
tology covers a wide field. It includes the deviations 
from the usual arrangement of the parts, such as the 
union of organs and alterations of position, as well as 
deviations from the form, number and size of the parts 
of the plant. Frequently an explanation does not readily 
offer itself, at other times the inciting cause is demon- 
strated without trouble. 

Though it is only in comparatively recent years that the 
true value of the study of abnormal forms has been real- 
ized, it must not be thought that in the earlier days the 
subject was overlooked. Numerous papers on terato- 
logical cases were published during the seventeenth cen- 
tury, for instance that by Wurffbain.! The eighteenth 
century saw an increase in the number of similar publica- 
tions. Even Linneus, before he enunciated his ‘‘varie- 
tates levissimas non curat botanicus,’’ seems to have de- 
voted some time to the study of abnormal forms.” At the 
same time, it was not until 1814 that the first collective 
publication on this subject, covering more than 300 pages 
and containing several illustrations, appeared.* This, at 
greater or lesser intervals, was followed. by others, the 

1 Wurffbain, Johannes Paulus. De folia lactucæ monstroso. ‘‘ Miscell. 
Acad. Nat. Curios.,’’ Dee. 2, A. 10, 411, 1691. 

?Linneus, Carolus. Pommerantz med et inneslutit foster. ‘‘ Vetensk. 


Akad. Handl.,’’ A. 281, 1745. 
3 Jaeger, G. F. Ueber die Missbildungen der Gewichse. Stuttgart, 1814. 


81 


82 THE AMERICAN NATURALIST (Von. XLII 


most important being those of Schlotterbeck,* Engel- 
mann® and Moquin-Tandon.* Since the middle of the 
last century numerous smaller papers on teratological 
subjects have appeared. The earlier data have been col- 
lected by Masters‘ and by Penzig,* in the former publica- 
tion the abnormalities being arranged according to kind. 
in the latter under the various families, genera and 
species. 

The main point of interest in abnormal forms lies not 
in the mere fact of the existence of the abnormalities nor 
in the extremes which they may reach, but rather in the 
light thrown by them upon plant development,’ and they 
are therefore entitled to equal consideration with hybrid- 
ization '° which, as de Vries * has pointed out, permits the 
analysis of the specific characters and thereby makes pos- 
sible the study of a single character, since the plant is to 
be considered merely as an expression of the reaction of 
elementary units, sometimes occurring singly, at other 
times in groups. 

mong the plant monstrosities which are most fre- 
quently observed are fasciations, in which more often the 
stems, but sometimes other parts of the plant, appear to 
broaden and assume a flat appearance. Their existence 
has been known for centuries, for instance the fasciation 
of Sedum reflexum (S. crispum), illustrated by Munting’? 

*Schlotterbeck, P. J. Schediasma botanicum de monstris plantarum quo 
analogiam regno vegetabili cum animali intercedentem in producendis 
iisdem adstruit et figuris illustrat. Acta Helvetica, 2: 1, 1816. 

5 Engelmann, G. De Antholysi Prodromus. Frankfurt a. M., 1832. 

€ Moquin-Tandon, A. Éléments de Tératologie Végétale. Paris, 1841. 

7 Masters, M. T. Vegetable Teratology, London, 1869. 

ee O. Pflanzen Teratologie. Genua, 1890-1894. 

oebel, K. Bedeutung der Misbildungen fiir die Theorie der Organ- 
bildung Organographie der Pflanzen, 173, 1898-1901. 

schermak, E. The Importance of Hybridization in the Study of De- 
soe Report of the Third International Conference on Genetics, Royal 
Horticultural. Society, 278-284, 1906. 

“de Vries, Hugo. In P Pangenesis. Jena, 1889. Sur les 
unités des charactères spécifiques et leur application a Vétude des hybrides. 
Rev. gén. fet 12: 257, 1900. 

“Munting, A. Waare Oeffeninge der Planten, 1672. 


No. 494] FASCIATIONS OF KNOWN CAUSATION 83 


and in numerous species, in fact, in so many species, in so 
many genera and in so many families, among fungi, 
among gymnosperms, among monocotyledons and dicoty- 
ledons, on herbs, on shrubs and on trees, that the assump- 
tion appears justified that fasciation may be expected to 
make its appearance at some time, in some part, in any 
species. This is the view held by Sorauer,'* but de Vries" 
does not make so sweeping a statement. 

Fasciations may be propagated vegetatively, for in- 
stance, by means of tubers, as in Oxalis crenata’ or 
through cuttings, as was done at the Missouri Botanical 
Garden for fasciations of the tomato, Solanum Lycoper- 
sicum, snap-dragon, Antirrhinum majus, hen-and-chick- 
ens, Echeveria glauca and others. Fasciations may also 
be transmitted through seed. Among the best known 
instances is the cockscomb, Celosia cristata and its varie- 
ties, which, because of this abnormality, is cultivated in 
gardens. It is a form which, like the cockscomb ama- 
ranth, Amaranthus cristatus, has been known for cen- 
turies to exist, and is always propagated through seed. 
Recently it has again been shown for Munting’s Sedum 
reflexum’? as previously by de Vries." 

The possibility of the transmission of the fasciated 
character to the offspring, had already been recognized 
by Godron t8 who, however, says: ‘‘ Les fasciés sont rare- 
ment héréditaires et jamais d’une maniére absolue.’’ 
While the truth of the latter part of the statement has 
been borne out by subsequent work, in the light of experi- 
ments carried on during the last twenty years, and espe- 
cially those of de Vries,'® the first part should be amended. 

33 Sorauer, P. Handbuch der a ae pe i **Die 


Fähigkeit zur Fasciation ist bei allen Pflanzen voraus 
“De Vries, Hugo. Die V STERNER 2: 551. Teas 1901-1903. 


mi ? 
18 Von Wettstein, R. Die Erblichkeit der Merkmale von Knospenmu- 
tationen. Festschrift zu P. Ascherson ’s Siebzigstem bebara 509, 1904. 

** Mutationstheorie, 1: 128. 

18 Godron, A. Mélanges de Tératologie Végétale. Mém. Soc. d. Sc. Nat. 
d. Cherbourg, 16: 97, 1871-1872. 

2 De Vries, Hugo. Over de erfelykheid der fasciatien. Avec un résumé 
en langue francaise. Bot. Jaarb. Dodonea, 6: 72, 1894. 


84 THE AMERICAN NATURALIST [Vou. XLII 


We have a right to believe that fasciations, like other 
monstrosities, with the exception, perhaps, of some cases 
of virescence,?? may be inherited, though not by all de- 
scendants. Else such varieties could not be offered on 
‘the exchange list of the Amsterdam botanic garden as 
Aster Tripolium fasciatum, Geranium molle fasciatum, 
Picris hieracoides fasciata, Veronica longifolia fasciata 
along with Chrysanthemum segetum fistulosum, in which 
the ligulate florets have become tubular like the disk 
flowers, Dipsacus sylvestris torsus, which has a twisted 
stem, Lychnis vespertina glabra, which lacks the tri- 
chomes on the pod, ete.?4 But it must be remembered that 
good soil, great care, especially in the earlier stages, 
plenty of room—in one word, optimum conditions only— 
give the desired result. 

Of far greater interest, at the present time at least, is 
the consideration of the causes of fasciation and its exact 
nature. Two kinds of fasciation appear to be possible. 
The one is caused by the combination, in a plane, of sev- 
eral axes, according to Lopriore.2? The other mode of 
fasciation, far more common, and the one which will be 
considered here, consists of the flattening of the stem 
through a broadening of its apical cone into a comb, as 
shown by Nestler,?* who did his work at the laboratory 


e Vries, Hugo. Een epidemie van E Avec un résumé 
en langue française. Bot. Jaarb. Dodonea, 
In at least one c: 


wer 
been shown that virescence may be transmitted through the seed (18th 

R issouri Botanical Garden, 99, 1907). The third observed, gen- 
eration of these plants, now degen 1908) in flower in the greenhouse, 
still shows the typical charac Now, as formerly, there is no sign of 
insects to which the cause of ia virescence could be attribut 

Vries, Hugo. Erfelyke monstrositeiten in den Paltbaxdel der 
botanische tuinen. Avec un résumé en langue francaise. Bot. Jaa 
sepa Ne 62, 1897. 

“Ló G. I ca ion anatomici delli radici nastriforme. Ex. in 
ceteris f Pa, 14: 226, 1904. 

‘ít Solche bandförmige pnas wurzeln entstehen entweder durch dichtes 
a mehrerer senkrecht raederas zylindri- 
schen, oder durch gleichsinnige Verwachsung der ralzylinder mehrerer 
Seitenwurzeln, die sich mit einer gemeinsamen a umgeben.’’ 

* Nestler, A. Untersuchungen über Fasciationen. Oester. Bot. Zeitschr., 
44: 343, 1894, 


No. 494] FASCIATIONS OF KNOWN CAUSATION 85 


for plant physiology at Amsterdam under the direction of 
de Vries. That we are dealing with but a single branch, 
and not several, though frequently the ribbed appearance 
of a fasciation gives cause to think otherwise, is well 
shown by Sorauer** in the case of a fasciation of the 
Norway spruce, Picea excelsa. It is demonstrated first 
of all by the position of the leaves, which are arranged 
in continuous spirals, and further by the cross sections of 
the fasciation at different points. They all show the 
vascular bundles and the pith arranged as a single, con- 
tinuous mass, and not as a combination of a number of 
adjacent rings, which would have been the case had the 
fasciation resulted through the union of various origi- 
nally distinct branches. 

For the sake of convenience in discussion, the causes 
of malformations in general and fasciation in particular 
will be considered under four heads: (1) Mechanical ac- 
tion, brought about by the elements, man or other verte- 
brates; (2) cases where no injury can be traced; (3) the 
action of fungi; and (4) the action of insects. 

Traumatisms appear, in the majority of cases, to be the 
inciting causes of the appearance of teratological charac- 
ters. Numerous instances of this are to be found through- 
out our literature. Blarighem *> found that in the case of 
the pansy, Viola tricolor var. maxima, it was caused by an 
accidental crushing of a young shoot. Similarly, he has 
been able to constatate?® that in clover fields which had 
been mowed twice, the number of individuals of red clover, 
Trifolium pratense, bearing 4-5-foliate leaves, was from 
12 to 37 per hundred, while in fields which never had been 
cut, but 5 to 8 such plants were found per thousand. 
Sainfoin, Onobrychis sativa, under the same conditions, 
produced in its pinnate leaf, leaflets grouped in threes 
and fours. Plants of the ox-eye daisy, PENON 


* Ibid., 333. 

* Blarighem, L. Production par traumatisme d’anomalies florales dont 
certaines sont héréditaires. Bull. Mus. d’Hist. Nat., 10: 399, 1904. 

* Blarighem, L. Anomalies héréditaires provoqués par les traumatismes. 
Compt. Rend. Acad. Sc., 140: 378, 1905. 


86 THE AMERICAN NATURALIST [ Vou. XLII 


vulgare (Chrysanthemum leucanthemum), of which the 
stems had been cut, bore heads on which at least a part 
of the ligulate flowers had been changed to tubular flow- 
ers, as well as heads, which in the axils of the bracts, bore 
secondary ligulate florets. Life?’ mentions the case of a 
plant of Ambrosia artemisiefolia which, having been run 
over by a wagon and badly injured in consequence, bore 
both staminate and pistillate flowers in an abnormal con- 
dition. A hedge composed of plants of Cereus margt- 


“ROSA DE ORGANO ’’—Cereus marginatus. 


natus, which, under the name Organo, is largely used as a 
hedge plant in Mexico, which was partly injured, prob- 
ably because of securing cuttings for planting, shows 
numerous fasciations.2* Klebs?? mentions the observa- 
tions of Krasan, who noted fasciation caused by a loss of 
leaves through the action of june bugs or spring frosts. 
~ Life, A. C. An Abnormal Ambrosia. Bot. Gaz., 38: 383, 1904. 

* A photograph, by Professor Frederick Starr (reproduced here), illus- 

trating a large portion of a hedge thus fasciated, and a cast of one of the 


branches, are in the herbarium of the Missouri Botanical Garden. 
Trans. Acad. Sc. St. Louis, 9: xx, 1899. 
Klebs, U 


G. eber künstliche Metamorphosen. Abh. naturf. Gesell. 
Halle, 25: 134, 1903-1906 ; 


See also 


No. 494] FASCIATIONS OF KNOWN CAUSATION 87 


It is but natural to suppose that if accidental mechanical 
injury can produce abnormalities, the same can be pro- 
duced experimentally through similar action. Again, 
numerous cases are on record. The first instance known 
is probably the experiment of Sachs,*® who, amputating 
the main stem of bean seedlings just above the cotyledons, 
was able to bring about fasciation of the shoots produced 
from the buds in the axils of the cotyledons. A fasciation 
of Ibervillea sonore at the New York Botanical Garden, 
referred to in Torreya,*! is understood to have been arti- 
ficially caused by intentional slight injury of the growing 
tip. Blarighem *? was able to cause fasciation of shoots of 
Viola tricolor var. maxima by crushing the young stems. 
Lopriore,** incited by the experiments of Sachs, cut the 
root tips of seedlings of Vicia Faba and obtained fasciated 
roots in a large number of cases, as well as malformations 
of other parts of the plant. 

But apparently a fasciation is not necessarily a conse- 
quence of mutilation. Goebel** mentions fasciations in 
suckers and watersprouts. These are so common that 
they probably have come within every one’s notice. Fas- 
ciations also frequently occur in plants the seedlings of 
which were abnormal in having a larger number of coty- 
ledons than usual. It has been shown** that under 
proper conditions of moisture and food, plants will fre- 
quently fasciate, though adjacent plants may remain nor- 
mal. Such cases have generally been ascribed to peculiar 
conditions of nutrition. 

” Sachs, J. Physiologische Versuche über die Keimung der Schmink- 
bohne (Phaseolus multiflorus). Sitzungsber. d. k. k. ad. d. Wiss. in 
Wien, 37: 57, 1859. 

* Knox, Alice A. Fasciations in Drosera, Ibervillea, and ar 
Torreya, 7°: 102. 
cit. 

* Lopriore, G. Verbianderung infolge des Képfens. Ber. d. d. Bot. Ges., 
22: 304, 1904. 

“Goebel, K. Organographie der Pflanzen, 164, 1898-1901. 

De Vries, Hugo. Eine Methode, Zwangsdrehungen aufzusuchen. Ber. 
d. d. Bot. Ges., 12°: 25, 1894. 

* 17th Ann. Rep. Missouri Botanical Garden, 147, 1906. 


88 THE AMERICAN NATURALIST [Von XLII 


That parasitic fungi are able to produce an alteration 
of form in plants has long been known. One of the most 
familiar abnormal growths from such a cause is what is 
commonly termed a witch’s broom, so often observed on 
evergreens. It is due to the action of species of Exoascus 
and Æcidum, which induce the formation of a large num- 
ber of adventitious buds within a comparatively short 
area of the stem or branch, which give rise to a corre- 
sponding number of short, thickened twigs. In the silver 
fir, Abies pectinata, witches brooms are produced by 
ZA cidium elatinum.®* Frequently galls are produced by 
fungi, affecting either roots, stems or leaves, but no cases 
are on record where a fungus was shown to be the cause 
of fasciation. This is different where gall-insects are 
concerned. Here some cases have been traced directly to 
gall-insects 38 as the cause. 

Galls, otherwise known as cecidia, and distinguished 
according to their origin into zoo- and phytocecidia, are 
among the most interesting of the abnormal forms which 
from time to time make their appearance as excrescences 
of widely varying shape, color and structure. Recognized 
by Pliny, some were even in those early days used in 
medicine because of their astringent properties. To-day, 
a number of them, especially some occurring on certain 
species of Quercus, Pistacia, Rhus and Tamarix, are of 
economic value?’ on account of their tannin content, and 
a gall produced by Cynips tinctoria upon branches of the 
dyer’s oak, Quercus lusitanica (Q. infectoria), found in 
the countries bordering the Mediterranean and in the 
Orient, is official in the U. S. Pharmacopeeia. Members of 
widely different orders of insects may be the cause of the 


* Kerner, A., and Oliver, F. W. The Natural History of Plants, 2: 527, 
London, 189 5. 

3 Though gall insects only are discussed here it does not follow that 
larvee of other insects may not be the cause of fasciation. The relation 
between fasciation in species of (Enothera and the larve of a small moth, 
Mompha, is discussed in a very interesting, well illustrated paper by Hnos, 
The Plant World, 10°: 145. 

* Wiesner, J. Die Rohstoffe des Pilaaconretahen, 1: 674, Leipzig, 1900. 


No. 494] FASCIATIONS OF KNOWN CAUSATION 89 


production of a gall. Among the Arachnida, many of the 
mites do so, some species causing serious injuries; for 
instance, the pear leaf blister mite, Hriophyes pyri, and E. 
oleivorus, which causes the so-called ‘‘russet’’ oranges.*° 

To the Hemiptera, of which the plant-lice, Aphidide, 
are best known, belongs the dreaded Phylloxera vastatria, 
which some thirty years ago so seriously crippled the 
vineyards of France. It forms galls on both the leaves 
and the roots. The Diptera, to one of the families of 
which our common house fly belongs, yield the Cecido- 
myide. One of these very small insects is the cause of 
the goldenrod rose. Neither the Lepidoptera nor the 
Coleoptera have many members which are the cause of 
gall formation. This is different as far as the Hymen- 
optera are concerned. A large number of species, espe- 
cially those belonging to the Cynipide, are the cause of 
the formation of some of the largest, most strikingly 
colored galls, of which those occurring on oaks (Cynips) 
and roses (Rhodites) are probably the most familiar. 

In some eases the causation of fasciations has been as- 
cribed to gall-forming animals. Kerner‘! speaks of the 
fasciations of the ash, Fraxinus excelsior and F. ornus, 
caused by a mite, Phytoptus (Eriophyes). De Vries *? 
mentions a stem of Hieracium vulgatum attacked by Au- . 
lax Hieracti which was normal below the gall, but above it 
was fasciated. Not only fasciations, but numerous other 
monstrosities have been brought into relation with gall 
insects. Treub*? observed virescence caused by the same 
insect. Nalepatt mentions Phytoptus anthocoptes as 
the cause of virescence of flowers, thickening of the capita — 
and frequent secondary formation of capitula on Cirsium 

“© Cook, M. T. Insect galls of Indiana. Tadiana Dep. of Geol. and Nat. 
Res., 29th Annual Report, 801, 1904. 

“ Ibid., 2: 549. 

“ Mutationstheorie, 1: 291. 

Treub, M. Notice sur l’aigrette des Composées a propos d’une mon- 
struosité de 1’Hieracium umbellatum. Arch. Neérl. d. sc. phys. et nat., 8: 1. 

“ Nalepa, A. Neue Arten der Gattung Phytoptus und Cecidophyes. 
Denkschr. d. k. Acad. d. Wiss., 59: 525, 1892. 


90 THE AMERICAN NATURALIST [Vou. XLII 


arvense, P. cladophthirus as the cause of gray-hirsute mal- 
formations of the shoots of Solanum Dulcamara, and P. 
geniste as the cause of malformations of the tips of the 
shoots and abnormal hirsuteness of the buds of Genista 
pilosa and Sarothamnus scoparius. The virescence of 
the inflorescence of different species of Arabis, due to 
Aphides, was studied by Peyritsch.** De Vries ** ascribes 
an epidemic of virescence among the plants in his experi- 
mental garden to an original infection caused by Phytop- 
tus, though he was unable to demonstrate the presence of 
the mite. Finally Molliard4* investigated the influence of 
fungi and insects causing floral cecidia upon the repro- 
ductive cells. 

From the above it will be gathered that there exists a 
very definite relation between malformation in plants and 
gall-insects. For this reason a large number of strikingly 
abnormal plants of the horse-weed, Erigeron canadensis, 
growing within a narrowly circumscribed area in the im- 
mediate vicinity of St. Louis, Mo., attracted immediate 
attention and awakened considerable interest. Being 
found in January, nothing but the dried parts remained, 
which made observation easier. All of the plants were 
abnormal. Among them two distinct types could be dis- 
tinguished. These types agreed in one particular. From 
the ground to a place 24-3 feet above the soil, the plants 
were normal. It was above this point that the abnor- 
mality presented itself. In the first type, when the plant 
had reached a height of from 24-3 feet above the ground 
it had evidently experienced a check. The main stem 
terminated here in a very much dried-up shoot but an 
inch or less in length, showing that it never had an op- 
portunity to perfect its woody tissue. Just below this 
point numerous small side shoots occurred. These side 

“ Peyritsch, J. Zur Ætiologie der Chloranthien einiger Arabis Arten. 
Jahr. f. Wiss. Bot., 13: 1, 1882. 

“De Vries, Hugo. Een epidemie van vergroeningen. Bot. Jaarb. Do- 
domea, 8: 66, 1896. 

“Molliard, M. Recherches sur les Cécidies Florales. Ann. d. Sc. nat. 
bot., 8. Sér., 1: 67, 1895. 


— 


ate # P at, cI 
\ ks a < oe mn 
EN — ee 
Pri ` Ñ E Oh” AR 
\ 4 Se 
Ce ie 
er y ET = z 
PILA Da r i 
f is 4 `, he 
A gta p | Š 


CECIDOMYIAN DEFORMITIES OF Erigeron. 


92 THE AMERICAN NATURALIST [Vou. XLII 


shoots had an average length of from 14-2 feet, and, 
issuing within a space of 3 inches from the atrophied tip, 
gave the dried plant a peculiar broom-like appearance. 
Upon them, usually immediately at the base, frequently 
within 2 or 3 inches from the base and sometimes at a 
distance of one foot from the base of the side shoot, oc- 
curred elongated swellings, from 3-% inch long and in- 
creasing the thickness of the stem to three times its nor- 
mal size. These also occurred on stems of the second type, 
which bore fasciations. Each of the swellings contained 
a single orange-colored larva, which Dr. M. T. Cook kindly 
determined as that of Cecidomyiaorigerom. The species 
of Diptera, to which Cecidomyia belongs, lay their eggs 
on the surface of the plant, and the larve, after hatching, 
penetrate the tissues. In this they agree with the Arach- 
nida and Hemiptera. The Hymenoptera puncture the tis- 
sues and deposit their eggs within the plant tissues. It 
has long been a question in exactly what manner the ab- 
normal growth due to gall insects is caused. Some as- 
cribe it to mere mechanical irritation on the part of the 
larvæ, others believe it to be due to a chemical stimulus 
emanating either from the parent insect, which, at least in 
some instances, deposits, along with the egg, a certain 
chemical substance, or from the young larve only.48 The 
latter happens in the case of the gall caused by Cecidomyia 
Poe upon Poa nemoralis? and which brings about the 
formation of roots in places where normally they are 
never found. But when Nematus Capree makes a wound 
in the leaf tissue for the purpose of depositing an egg, a 
gall develops, whether an egg is laid or not. Even when 
the former has taken place, though the egg be subse- 
quently destroyed, the gall develops just the same, though 
never attaining full size. For that matter, mere mechan- 
ical irritation, i. e., the killing of one or a few cells at the 

“ Beyerinck, M. W. Beobachtungen über die ersten Entwickelungs- 


phasen einiger Cynipidengallen, 177. Veröffentlicht d. d. k. Acad. d. Wiss. 
zu Amsterdam, 1882. 


° Beyerinck, M. W. Die Galle von Cecidomyia Pow an Poa nemoralis. 
Bot. Zeit., 43”: 304, 1885. 


No. 494] FASCLATIONS OF KNOWN CAUSATION 93 


side of an organ, may result in the malformation of the 
adult organ, and, according to Ward,” may be proved 
experimentally by aid of a needle. But the assumption 
of a mere mechanical injury is not sufficient to account 
for the presence and shape of galls. The same insect, on 
different hosts, may produce different galls. Again, two 
distinct species of gall-insects produce very different galls 
on the same plant or even on the same leaf. Further, ex- 
periments to bring about artificially the formation of galls 
through the injection of different chemicals, have thus 
far proved unsuccessful.” 

Among plants of Erigeron canadensis fasciation ap- 
pears to be quite common.®? When, however, among the 
plants of this fleabane infected by the Cecidomyia a large 
number, at least 10 per cent., were found to be fasciated, 
it was but natural to attempt to bring the two phenomena 
into relation. In some of these fasciated plants the fasci- 
ation begins within two feet of the ground; in others, and 
these form the majority, the fasciation began from 23-3 
feet above the soil surface and above the point where the 
galls occurred on the main stem. But while the non- 
fasciated plants showed a large number of long side 
shoots, developed at the expense of the main stem, the 
fasciated plants did not differ materially from normal 
plants in this regard. A large number of short side shoots 
bearing flowers were produced on a fasciated main stem. 
The most plausible explanation is that in the former case 
the growth of the main stem was inhibited absolutely and 
that all the strength went to form side shoots, while in the 
latter case the growing point was not affected sufficiently 
to dry up. Instead, growth was stimulated. Whether the 
action of the galls was of a mechanical or chemical nature, 
though of great interest in other cases, is of compara- 
tively little importance here, and for the following 
reasons: 

” Ward, H. Marshall. Disease in Plants, 131, London, 1901. 

" Kiistenmacher, M. Bei itrage zur Kerntnis der Gallenbildungen mit 


i sy des Gerbstoffes. Jahrb. f. wiss. Bot., 26: 82, 1894. 
Penzig, loc. cit. 


94 THE AMERICAN NATURALIST [ Vou. XLII 


It has been conceded generally that fasciations are 
due to changed conditions of nutrition. Nestler, de Vries, 
Goebel, Sorauer and many others agree that they are 
induced either through an increase of nutrition of the 
entire plant or of that of certain shoots through the re- 
moval of others. In other words, it is due to a change of 
the chemical and physical conditions within the cell. The 
influence of chemical substances upon plant and animal 
cells has been widely studied. Among the best known are 
the experiments of Johannsen ** in which lilac bushes and 
other flowering shrubs, of which we see the branches in 
the florist’s windows in early spring, under proper con- 
ditions of moisture and temperature, were for a certain 
length of time exposed to the action of ether or chloro. 
form, after which they bloomed several months earlier 
than normally would have been the case. Loeb’s experi- 
ments on the cleavage of unfertilized eggs of the sea 
urchin, after having been treated with magnesium chlo- 
ride, are too well known to make it necessary to go into 
detail. The same thing is true for his studies on the 
influence of the lack of oxygen and resultant modifica- 
tion in the cleavage of eggs of Echinodermata. Migula’s 
experiments on the influence of dilute acid solutions on 
algal cells, Richards’ work on the development of fungi 
under the influence of chemical stimuli, and especially 
the work of Sabline on the influence of external agents 
on the roots of Vicia Faba show that external influences 
may bring about profound nuclear changes. Still better, 
this is brought out by the injection experiments of Mac- 
Dougal,°* who was able to produce new species through 
the injection of dilute salt solutions into the capsules of 
evening primroses. And in the case of hyphæ of many of 
the Chytridiacee, which bring about abnormal cell di- 
visions in the tissues of the host plant, the protoplasm of 
pee Johannsen, W. Das Aetherverfahren beim Friihtreiben, 2° Aufl., Jena, 
** MacDougal, D. T., A. C. Vail and G. H. Shull. Mutations, Variations 
and Relationships of (inotheras. Carnegie Institution of Washington 
Publication, No. 81, 1907. 


No. 494] FASCIATIONS OF KNOWN CAUSATION 95 


the parasite never comes in direct contact with that of 
the host. Yet their influence extends to cells at some 
distance from the point of infection. Even where the 
hyphze do not actually enter the cell, a stimulation to 
abnormal growth often takes place. Experimentally 
mere mechanical action has brought about profound 
changes. Molliard was able to induce the formation of 
double flowers through mechanical irritation. 

That the action of galls is of a chemical nature is well 
shown by Molliard,®> who describes and figures profound 
nuclear changes preceding the hypertrophy of Geranium 
sanguineum attacked by Phytoptus Geranit. 

If fasciations, which are due directly to chemical 
changes within the cells, may be inherited, then why not 
galls? But acorns from an oak covered by galls produce 
normal plants only. Still, one might expect galls to be 
inherited in preference to fasciations. Does not de 
Vries °° say: ‘‘It is clear that the beautiful, highly com- 
plex and judicious structure of the cynipid galls, with 
their food tissue, layers of stone cells, and the tannin- 
bearing, loose, outer parenchyma, in thickness adapted 
to the egg apparatus of the parasites and inquiline, can 
not be brought about by a mere mechanical stimulus.’’ 
Kerner goes so far as to say that it is within the limits 
of possibility that the first double flowers were caused by 
some gall. 

There is no direct evidence of the inheritance of abnor- 
malities brought about through the influence of gall in- 
sects or their larve. Fasciation, however, from whatever 
cause, may be inherited by a greater or less percentage 
of the offspring. We may then assume there must be a 
predisposition to the formation of fasciation in all plants 
which up to this time have been known to produce them. 
Probably this disposition is present in all other plants. 
The assumption of a mere excess of nutrition is not 

** Molliard, M. Hypertrophie pathologique des cellules végétales. Rev. 
gén. bot., 9%: 33, 1897. 

°° Mutationstheorie, 1: 290. 


96 THE AMERICAN NATURALIST [ Vou. XLII 


sufficient to explain the inheritance of the character. It 
is necessary to assume a corresponding and very definite 
change in the bearers of the hereditary characters. Just 
how these bearers are constituted or what name is given 
them is entirely immaterial. It is probable that they are 
of an exceedingly complex nature. For purposes of illus- 
tration they may well be compared with the molecules of 
organic chemistry, or better still, as has already been 
done so felicitously, to many-sided prisms, which a very 
slight jar causes to assume a different position and which 
finds a corresponding external expression. Under pre- 
disposition to fasciation or the latency of the fasciated 
character should perhaps be understood a tendency on 
the part of the cell contents, and more particularly the 
chromatin, to undergo a certain definite change, retained 
during cell division, of either a chemical or physical 
nature, under certain conditions brought about by differ- 
ences in nutrition. The change which causes fasciation is 
one of the easiest brought about, and hence fasciation is 
one of the abnormal characters most frequently met with. 
Though a mere theory, its general truth is supported by a 
number of instances. Mutations frequently repeat them- 
selves. The identical sports originating from stock ob- 
tained from widely different sources and where the proba- 
bility of a common origin in the remote past may safely 
be questioned, speak for themselves. The finding in two 
distinct places in Europe of plants of Capsella heegeri 
Solms, which differs from C. bursa-pastoris mainly in the 
shape of its capsules, is another instance. Mutations in 
a species are always the same, whatever their direction. 
They may be widely separated in time and space, but 
whenever they appear they are identical. 

It has been said that fasciations are inherited because 
the seeds collected for purposes of propagation always 
were obtained from the abnormal stems. This appears 
to have happened in the majority of cases. Since, how- 
ever, we never can know whether a fasciation is inherited 


No. 494] FASCIATIONS OF KNOWN CAUSATION 97 


or makes its appearance for the first time,°’ numerous 
experiments should be undertaken with a view of elimi- 
nating ‘‘chance’’ through large numbers. Whether the 
seed of a bean in which a fasciated root has been pro- 
duced artificially, gives rise to a fasciated plant, is an 
experiment worth trying. Likewise, it is an open question 
whether the seed borne on normal stems of a pansy in 
the main stem of which fasciation has been induced 
through crushing, will give rise to fasciated individuals. 
The spores of the Boston fern, Nephrolepis exaltata bos- 
toniensis, give rise to plants the majority of which ex- 
hibit the peculiar cristate leaves. Yet here and there on 
the fronds sometimes will be found non-cristate leaflets. 
Will the spores borne on the latter give rise to the cristate 
form? These are experiments which any one with a 
little space and time at his command and a penchant for 
gardening, can readily undertake. To such, no small 
hope of reward is held out in a recent paper by Blarig- 
hem,°* who, as a result of mutilation, obtained entirely 
new and constant varieties. 

5 This is true even when it appears as a bud variation, for the character 
may have been latent in the parent plant. One can, meyeni not speak, in 
such a case, of an ‘‘acquired’’ character in the strictest sen 

** Blarighem, L. Action des traumatismes sur la neede et ]’héridité. 
Compt. Rend. hebd. d. Séanc. et Mém. de la Soc. de Biol., 57°: 456, 1905. 


THE AGGREGATE ORIGINATION OF PARASITIC 
PLANTS 


DR. CHARLES A. WHITE 


SMITHSONIAN INSTITUTION 


In the January number of THe Narurauist I gave a 
review of the known phenogamous parasites, in which 
was discussed the relation of the parasites to one another, 
and to other abnormal plants; and the relation of all of 
them to normal plants. The present- article is devoted 
mainly to the question of the manner of origination of 
the parasites as such; which, it is assumed, was by abnor- 
mal aggregate mutation from normal phenogams. 

Parasitism in the animal kingdom is perpetrated by 
low, upon higher, forms of life, the parasites belonging 
to families, orders and even to classes, which are widely 
different from any of those which include the hosts. 
Parasitism of low forms of vegetable life upon higher 
forms is also everywhere prevalent, such as that of fun- 
goid cryptogams upon phenogams, but the cases now 
under consideration are those of parasitism of various 
kinds of phenogamous plants upon other phenogams. 
Evidence of this phylogenetic relationship of parasites 
and their hosts, even in extreme cases of parasitic defor- 
mation, is fortunately preserved in that part of the struc- 
ture of the parasites which pertains to parturital repro- 
duction. Thatis, the florescence and fruitage of the para- 
sites have remained characteristically phenogamous, each 
parasitic species having preserved at least those floral 
and pericarpal structures which normally characterize the 
phenogamous families, as such. It is thus observable 
that, in the abnormal mutation which produced the para- 
sites, the effect was chiefly confined to the somatic parts 
of the respective plants and to those parts which are con- 
cerned in blastemal reproduction; while the parts imme- 
diately concerned in systematic genesis by parturital 

98 


No. 494] PARASITIC PLANTS 99 


reproduction were, at most, only slightly disturbed. So 
distinctly are the systematic characters of normal pheno- 
gams retained in the florescence and fruitage of the para- 
sites that one seems forced to the conclusion that, in the 
great systematic development of vegetal forms, they all 
became phenogams before they became parasites. The 
phenogamous parasites, therefore, not only do not belong 
to a separate and predatory class, as is the case with 
other parasites, but they are depraved members of the 
same class, and sometimes of the same family, with their 
hosts. Still, their depravity is only with reference to 
the habits and structure of normal plants, for they all 
have great adaptability to their peculiar conditions, and 
their vegetal vigor is quite as great as is that of normal 
plants. 

It is a fact worthy of special attention in this connec- 
tion that although all the various forms of phenogamous 
parasitism are accompanied by greater or less abnormal- 
ity of structure, they are in certain respects subject to the 
systematic restrictions which pertain to normal plants. 
That is, each form of parasitism affects not merely cer- 
tain individual members of a given species, but every 
member of it; and the systematic limits of that species 
are, for itself, the limits of its own peculiar form of para- 
sitism. Moreover, that form of parasitism which char- 
acterizes each of the different groups is shared without 
variation by every member of the group regardless of 
the generic or family relationship which it may bear to 
other plants. The habits and other parasitic characters 
of those depraved phenogams are as distinctly and per- 
manently heritable as are the stated specific, and other 
systematic, characters of the same, or of any other, 
species, and there is no known evidence that any form of 
phenogamous parasitism has been derived by transmu- 
tation from any other parasitic form. Known evidence 
tends to show that every case of such parasitism origi- 
nated independently of all other cases, and by a mutative 
process which imposed permanent abnormal characters 


100 THE AMERICAN NATURALIST (Von. XLII 


upon normal plants. Those abnormal characters all be- 
came connate with the normal characters after the estab- 
lishment of their heredity, but they never became sys- 
tematically correlated with them. 

The questions that here almost crowd themselves upon 
one’s attention are, how have those wayward phenogams 
accomplished their departures from normal conditions, 
and what was their incentive for doing so? Doubtless in 
all cases the chief incentive to parasitism, after the opera- 
tion of an unknown predeterminate cause, has been food- 
lust, the instinctive object of the plant being to procure its 
nourishment in an immediately available form. The fol- 
lowing respective references to the seven groups of phe- 
nogamous parasites are necessary to the present subject, 
but they show how difficult it is to make any sufficient 
answer to the first of those questions. 

In pursuance of the subject as just indicated it may be 
suggested that the members of group I, which prey upon 
the roots of other plants and are only partially parasitic, 
originally acquired their habit of underground pilfering 
by the accidental chafing together of the tender roots of 
closely-growing plants, which brought bared, new-formed 
cells into contact at the crossings of the roots. Vital 
union of the roots at those points, such as takes place in 
grafting, having resulted, the more vigorous plant be- 
came the parasite by withdrawing a portion of the partly 
elaborated food-sap from the weaker one. It is plain, 
however, that thousands of cases are constantly occurring 
of similar contact of growing roots which do not result 
in parasitism. Both the normal and abnormal charac- 
ters are possessed by every individual plant of every 
species pertaining to group I, and they are thus, all to 
the same extent, distinguished from normal plants and 
from all other parasites. In no case is one of this sim- 
plest of the forms of phenogamous parasitism known to 
show any inclination to greater complexity, or to abandon 
its present restricted parasitic habit. The heredity of 
that habit is permanent, and no known fact suggests that 


No. 494] PARASITIC PLANTS 101 


it originated by any slow process, such as is generally 
understood to be the case in natural selection. 

The mistletoes, which represent group II, have reached 
the condition of complete parasitism with less structural 
and functional change than have any of the other recog- 
nized groups. In view of the fact that they produce 
their own chlorophyl, and that their structure is very 
nearly normal, one can not doubt that they were origi- 
nally normal phenogams, growing from the soil, although 
they will not now grow there. As a family also, they are 
now quite distinct from all other families, and as a group 
of parasites they are so clearly separate from every other 
group that one can not doubt that they have reached their 
parasitic condition in an entirely different manner. Their 
departure from the life-habit of normal phenogams evi- 
dently consisted only of the transference of germination 
and epitropism from the soil to the bark of trees; while 
the epitropic structure and functions, including both par- 
turital and blastemal reproduction remained normal. 
Unnatural and lacking in apparent incentive as has been 
that transference, it is believed to have been suddenly 
accomplished for the whole family, no trace of transi- 
tional stages of parasitism having been discovered for 
the species of either the Old World or the New. Although 
the mistletoes are so nearly normal in structure, their 
parasitism is as complete and heritable as is that of any 
of the other groups. 

The European species, Lathrea squamaria, which has 
been chosen to represent group III, besides being distinct 
from all other known parasitic forms, is, in a peculiar 
manner, suggestive of the assumed suddenness with which 
changes from normal to parasitic conditions have oc- 
curred among phenogams. This species has five distinct 
abnormal habitudes, which are repeated in succession in 
every individual plant. Its germination is from an ordi- 
nary seed in surface soil, and it is developed as a normal 
plantlet from a normal embryo; but it soon abandons 
itself to a remarkably diversified life. First, it produces 


102 THE AMERICAN NATURALIST (Vou. XLII 


sessile haustoria upon some of its early roots and be- 
comes partly parasitic in the same manner as do the mem- 
bers of group I, the structure and habit of which it then 
closely resembles. Second, it resorts bodily and sud- 
denly to underground life by burrowing into the soil, 
where it becomes an intricate mass, often very large, of 
blanched stems and branches. Third, it abandons its 
early roots with their sessile haustoria, develops new 
pediculate haustoria from its underground stem and 
branches and becomes completely parasitic. Fourth, it 
changes some of its numerous aborted leaves into inge- 
nious traps with which it captures minute animal forms 
and adds them to its other ill-gotten subsistence. Fifth, 
almost suggestive of atonement for a groveling life, it 
provides for the normal germination of its offspring 
by sending above ground a few specialized branches which 
produce perfect flowers and seed and then die, while 
the underground parts live perennially. That series of 
changes of structure and habitude within the life-history 
of a single plant has no known parallel in the vegetable 
kingdom. The changes have no apparent relevancy with 
one another until the closing one of the series, parturital 
reproduction, restores the normal phenogamous condition 
for a new reproductive cycle and a new series of the 
abnormal changes. All these changes of structure and 
habitude are invariable in character and invariably heri- 
table. So far as is now known they are confined to a 
single species, and the structure of no other known plant 
offers any suggestion of their gradual origination. In 
view of such facts as these, all of which have been attested 
by competent observers, one may reasonably believe that 
not only this form, but all the forms of phenogamous 
parasites, have originated suddenly. 

Although groups I, IT and III are, by their respective 
methods of parasitism, clearly distinct from one another 
and from normal plants, parasitism is not physically man- 
ifested in any of them until after germination is com- 
pleted, because the embryo of every member of each of 


No. 494] PARASITIC PLANTS 103 


those groups is of normal structure. Every member of the 
four remaining groups, however, begins life in an embryo 
which is simple and filiform and without cotyledons, rad- 
icle and plumule, although the flower in which it is pro- 
duced is of normal phenogamous structure. Moreover, 
although the simple abnormal embryo is physically iden- 
tical for each of the four groups just mentioned, the 
resulting forms of parasitism are too widely different for 
each group to suggest for them even a remote community 
of origin. 

A remarkable fact concerning group IV is that the two 
genera which compose it, Cuscuta and Cassytha, belong 
to widely different families, namely, Convolvulacee and 
Lauracex, respectively, and that the respective genera 
prevail in distantly separated parts of the world. Both 
genera are endowed with a single parasitic impress which 
distinguishes and dominates them equally in both habi- 
tude and somatic structure. That impress also separates 
all the species and individual plants of the whole group 
from normal plants and from all other parasites. The 
habits of this group, as shown by our well-known dodders, 
are widely different from those of all the other parasitic 
groups. They are all annual plants and consequently 
the whole life history of each species is crowded into a 
single season, which is shortened by late spring germi- 
nation and early frosts. Therefore all the characteristics 
of the whole group lie dormant in the simple filiform 
embryo of every dodder seed for more than half of each 
year; and yet every one of those characteristics is invari- 
ably heritable and constant. Difficult as it is to under- 
stand how every individual member of such a distinctly 
defined double group of annual plants could have assumed 
their abnormal characteristics either slowly or suddenly, 
and attained a world-wide distribution, it is still more 
difficult to understand how two such diverse genera could 
have assumed identical parasitic characters. It is almost 
superfluous to add that the habits and structure of no 
known plant offers any suggestion of a gradual origina- 


104 THE AMERICAN NATURALIST [ Von. XLII 


tion of the parasitic characters of group IV, or of the 
manner of its world-wide distribution. 

` As is the case with the other groups which are herein 
mentioned, nothing is known of the pre-germinative his- 
tory of the characteristics of group V. The members of 
this group belong to a noted family of parasitic genera, 
the Orobancher, of which the destructive broom-rapes 
are among the best known examples. They all begin life 
in a simple, filiform embryo, which is not only without 
differentiation into cotyledons, radicle and plumule, but 
which is also extremely abnormal in its method of germi- 
nation. The members of group V; like those of group 
IV, are annuals. As regards the structure of the seed 
and embryo and the initial conditions of germination, the 
members of both groups are similar, but their results are 
extremely different. The germinating offshoot of the 
former springs upward, sending no root into the ground, 
but seizing upon the growing parts of its companion 
plants by its haustoria. The offshoot of the latter bur- 
rows downward and seeks a root-host, failing to find which 
it dies without producing any upward growth. Finding 
a root-host, a substituent plantlet is developed from 
their conjoined parts which rises above ground, producing 
flowers and seed. The physical structure of the embryo 
of both plants is identical, and both are abnormal. Im- 
mediately upon germination the great differences between 
the plants appear, but neither in those differences or 
in their common embryonal structure is there any sug- 
gestion of a community of origin with each other, or with 
any other plants. 

A leading characteristic of all the forms of phenog- 
amous parasitism is the permanence and heredity of their 
attributes. Increasing abnormality of structure and habit, 
however, is suggested, but not proved, by the members 
of group VI, which is represented by the Rafflesias and 
some closely related genera. The conception which one 
naturally forms of a phenogam that may have been the 
normal ancestor of these plants is one having root, stem, 


No. 494] PARASITIC PLANTS 105 


branches, leaves, flowers and fruit. These plants have 
discarded most of those essential parts, none of them 
having more than a short stem besides the fertile flower; 
and the sessile species, which are numerous, retain only 
the flower. Such a conception would therefore carry with 
it the idea that those eliminations were consecutively 
effected until the lowest structural limit was reached; but - 
neither their own structure nor that of any other known 
plants affords the least indication that any of these para- 
sites reached their present condition by either selective 
gradation of successive steps. The Rafflesias, like the 
mistletoes, are parasitic upon trees, and the seeds of both 
will not germinate successfully upon the ground. One 
may well believe that when the mistletoes abandoned the 
soil and inflicted themselves upon trees they took with 
them, and retained, all that they then needed for their 
support. But when the Rafflesias made their similar 
change, as they are assumed to have done, they required 
from their hosts the fullest possible tribute. Apparently 
sure of receiving it, they discarded as no longer necessary 
the principal part of their own somatic and blastemal 
structures, the sessile species retaining only those parts 
which are concerned in parturital reproduction, namely, 
only the flower. Their success has been complete, for 
-although they are rootless, stemless, branchless and leaf- 
less plants, and originate from a structureless embryo, 
they are among the most vigorous of vegetable forms, 
the flower of the largest species sometimes reaching a 
diameter of more than three feet. One cannot conceive 
of a wider departure from normal conditions than is pre- 
sented by group VI, or of a more complete isolation of 
structure and habit from all other plants. — 

Group VII, which is represented by the Balanophoree, 
is remarkable for the comparatively large number of sys- 
tematic genera which it embraces, some of which are so 
greatly differentiated from others as to deserve recog- 
nition as sub-families. Some are comparatively incon- 
spicuous; some produce large, showy flowers, and some 


106 THE AMERICAN NATURALIST [Vou. XLII 


bear an outward resemblance to fungi, to which early 
botanists referred them. The genera of this group are 
still further distinguished by the comparatively small 
number of species which represent them, the average 
number to the genus being less than three. Yet all the 
members of this remarkably diversified group are devel- 
oped from a simple filiform embryo by a germination 
similar to that of the broom-rapes, and all are rigidly con- 
trolled by one invariable and heritable method of para- 
sitism. It is almost superfluous to add that there are no 
known intermediate forms between the parasitic species 
of this group, or between them and normal phenogams. 

A leading purpose in the foregoing remarks is to ex- 
press the belief and present evidence that all the various 
methods, or forms, of phenogamous parasitism have 
originated suddenly by abnormal mutation from normal 
phenogams and that each form originated independently 
of all the others. One can not doubt that, whatever may 
be the determinate cause, all mutations of plants, whether 
normal or abnormal, originated in changes of molecular 
conditions within the germ cell. Usually, those molecular 
changes are of phylogenetic character, but there is no 
reason to doubt that the changes which gave origin to the 
various parasitic attributes were also of like molecular 
origin. That is, referring to the theory of intracellular 
pangenesis of de Vries, each of those attributes, as well 
as their associated abnormalities of structure, both so- 
matic and embryonic, had its origin in abnormal pan- 
genes. Admitting such a community of molecular origin, 
there appears to be no more reason to doubt the origina- 
tion of parasites by aggregate mutation than to doubt 
normal aggregate mutation. 

One who accepts without qualification the theory of 
the origin of species by natural selection is no more 
likely to favor this idea of the sudden origination of 
the great and diverse groups of parasites which have 
been referred to in preceding paragraphs than he would 
be to accept the theory of special creation of species, 


No. 494] PARASITIC PLANTS 107 


belief in which was formerly universally held. But by 
those who have given due consideration to paleontolog- 
ical facts with regard to the evidently sudden introduc- 
tion at various stages of geological time, not merely of 
species, but orders and classes of animals and plants; 
to the great array of facts presented by Professor Hugo 
DeVries in support of his mutation theory ;? to the cases 
of aggregate mutation of Lycopersicum which I have 
published from time to time as results of my personal 
observations ;° and to like cases of aggregate mutation of 
Gossypium which have been observed by Dr. O. F. Cook,‘ 
the proposition that the different forms of phenogamous 
parasitism have been introduced separately and suddenly 
will not be hastily rejected. When the attention of one 
who holds the former of the two views referred to is called 
to the cases of evidently sudden introduction of animal 
and vegetable forms during geological time he usually 
replies by deploring the imperfection of the geological 
record, although he constantly depends upon it in the 
multitude of cases in which phylogenetic continuity is 
evident. And yet, there is no break in the geological 
record, which is more abrupt and differential than is that 
which exists between the distinguishing characters of the 
phenogamous parasites and the normal characters of 
every other phenogam now living contemporaneously 
with them. 

Briefly reviewing the foregoing subject, we find as, fol- 
lows: (1) The parasites which have been discussed are 

1I have discussed these questions in Report of the Smithsonian Insti- 
tution for 1901, pp. 631-640; Bulletin Torrey Botanical Club, New York, 
Vol. 29, pp. 511-522; Album der Naatur, Haarlem, April, 1903, pp. 231- 
238; Natur und Schule, Berlin and Leipzig, III Band, pp. 248-253; and 
Science, New York, Vol. XXII, n. s., pp. 105-113. 

2 Die Mutationstheorie, Leipzig, 1901. 

3 Science, n. s., Vol. XIV, pp. 841-844; ibid., Vol. XVII, pp. 76-78. 
New York Independent, Oct. 16, 1902; Bull. Torrey Bot. Club, Vol. 29, pp- 
511-522; The Popular Science Monthly, Vol. LXVII, June, 1905, pp. 


151-161. 
* Proc. Washington Acad. Sci., Vol. VIII, p. 265; Science, n. 8., XXVII, 


p. 193. 


108 THE AMERICAN NATURALIST [ Vou. XLII 


known to be phenogamous by the character of their flores- 
cence and fruitage, but for this occasion they are classified 
by their parasitic differences only. They are divided into 
no less than seven distinct groups, or kinds, which differ 
in character from root pilfering by means of a few haus- 
toria to dominant rapacity, extreme deformation of so- 
matic and embryonal structure and aberrant methods of 
germination. (2) The method of parasitism of each group 
is shared equally by every member of it, whatever may be 
the systematic affinities of the respective members, and 
the method of each group is entirely unlike that of every 
other group. (3) All the parasitic habits and structures 
are severally and completely heritable, and always con- 
nate with systematic features of the species in which they 
occur, but they are never systematically correlated with 
them. (4) None of the seven forms of parasitism shows 
any tendency to return to normal conditions, to become 
more complex, or to change from one form to another. 
(5) The normal florescence and fruitage of the parasites 
is assumed to indicate that they were originally derived . 
from normal phenogams; but no trace of intermediate 
stages between even the most extreme cases of parasitism 
and normal plants has been discovered. The geograph- 
ical distribution of all the known kinds of phenogamous 
parasitism, except that of group III, is almost world-wide. 
In consideration of these, and many kindred, facts it is 
assumed that the phenogamous parasites originated as 
such by sudden and aggregate mutation from normal 
phenogams, similar to, but not identical with, the phylo- 
genetic aggregate mutation that has been observed in 
Lycopersicum and Gossypium. 


THE EVOLUTION OF THE TERTIARY MAM- 
MALS, AND THE IMPORTANCE OF 
THEIR MIGRATIONS! 


PROFESSOR CHARLES DEPERET 


UNIVERSITY oF Lyons 


Norr.—These very interesting and important papers 
by Charles Depéret, Dean of the Faculty of Science, Uni- 
versity of Lyons, France, have been especially revised by 
the author (to date, November, 1907) before translation. 
The translation is the work of Miss Johanna Kroeber, 
graduate student of Columbia University. Dr. Charles 
R. Eastman of Harvard University and Dr. W. D. Mat- 
thew of the American Museum have kindly revised the 
translation. The correlation of the Tertiary of the Old 
and New World is of such commanding interest to pale- 
ontologists, zoologists and geologists, that this contribu- 
tion from one of the foremost paleontologists of the con- 
tinent is especially welcome. 

| Henry FAIRFIELD OSBORN. 
March 3, 1908. 


First Paper. Eocene ErocH 

In a preceding contribution (Comptes rendus, 5 juin, 
1905) upon the principles of evolution of the Tertiary 
mammals, I have enunciated the following general law: 
that when we attempt to establish the sequence of the 
forms which represent the evolution of a natural phylum 
we find ourselves, after tracing them backward through 
a geologic series of more or less length, almost always 
arrested by an impassable hiatus; this apparent break 
corresponds to the sudden appearance of the group under 

1 Extract from the Comptes rendus des séances de l'Académie des Sci- 
ences, t. CXLI, p. 702. (Séance du 6 novembre, 1905.) Translated by 
Johanna Kroeber. 

109 


110 THE AMERICAN NATURALIST [ Von. XLII 


consideration in the region of the globe which one is 
studying. 

It is desirable to return to this general law of faunal 
changes through migration and to illustrate its interest 
more fully. 

The importance of the migrations of terrestrial animals 
as correlated with great changes in the paleogeography 
of the continents, was fully recognized a century ago by 
Cuvier. The illustrious founder of paleontology had 
been justly impressed by the absence or rarity of forms 
of passage between the superposed fossil faune. Hxag- 
gerating somewhat, owing to the imperfect evidence 
before him, the consequences of this observed fact, Cuvier 
had deduced from it the renewal of faunz in toto (after 
their destruction by terrestrial cataclysms) not by suc- 
cessive creations, as he is often accused of advocating, 
but by extensive migrations of animals foreign to the 
region. Since his time, many paleontologists, Wallace, 
Lydekker, Zittel, Schlosser, Gaudry, Osborn, Ameghino, 
etc., have given their attention to this subject and have 
reiterated its significance. It appears to me, however, 
that these contributions have been of too speculative a 
character, inadequately supported by precise data. It 
has resulted that the majority of the essays at the genetic 
or structural phylogeny, which have been attempted in 
various groups of fossil mammals, are defective, chiefly 
because their authors have almost always sought to find 
in place in the particular country which they inhabit the 
various evolutionary series of these groups. 

No doubt there are great practical difficulties in re- 
fastening link to link the segments of the broken chain 
which forms the evolutionary series of each of the in- 
numerable branches of the mammalia. Nevertheless, the 
obstacles are smoothed away by each new discovery; thus 
the recent disinterment of the Oligocene and Eocene of 
the Libyan desert, of the ancestors of the Proboscidea, 
the Mastodons and Dinotherium, which appear so sud- 
denly in Europe at the beginning of the Miocene, and 


No. 494] THE TERTIARY MAMMALS 111 


whose origin has been until now an insoluble enigma, indi- 
cates the method we should follow, and the necessity for 
searching for the centers of dispersion of each branch. 

A preliminary work at least is possible at our present 
stage of knowledge; it is to establish for each region 
whose paleontologic exploration is sufficiently advanced, 
the part which pertains to each of the two factors deter- 
mining faunal changes: (1) Evolution of the local fauna 
(autochthonic evolution), (2) Immigrations from a distant 
region. 

I shall attempt to analyze these facts for the Tertiary 
faune of Europe, where this distinction has never been 
established in a systematic manner. 

I. Thanetian or Lower Londinian stage (deposits of la 
Fére, Cernay, Rilly, Chalons-sur-Vesle in France; of 
Erquelines in Belgium). 

1. Local Evolution.—A single instance, Neoplagiaulax 
(Multituberculata), which may perhaps have been de- 
rived, in spite of the great gap of the Cretaceous, from 
Plagiaulax of the Purbeck, but may also have migrated 
from North America. 

2. Migrations of North American Origin.—Introduc- 
tion into Europe of several families of Creodonta: Oxy- 
clenide (Procynictis—=Chriacus), Arctocyonide (Conas- 
pidotherium — Clenodon), Mesonychide (Dissacus) ; and 
of the Condylarthra (Euprotogonia). 

3. Migrations of unknown origin of the Insectivora 
(Adapisoricide), of the (?) Artiodactyla (Pleuraspido- 
theriide), of the aberrant Primates of the group Plesi- 
adapidæ, of the Perissodactyla (Hyracotheriide or Pre- 
equide), of the Amblypoda (Coryphodon). 

II. Sparnacian or Upper Londinian stage (deposits of 
Soissons, Guny, Muirancourt, Saron near Ste Maxence, 
Laon, Upper Cernay, Meudon, Vaugirard, Sézanne, in 
France; Dulwich and Croyden (Woolwich beds) in Eng- 
land. Fauna unfortunately still very scanty. 

1. Local Evolution.—Continuance of Amblypoda (Co- 
ryphodon, and of Hyracotheriide (? Pachynolophus). 


112 THE AMERICAN NATURALIST [ Vou. XLII 


2. North American Migrations of certain Creodonta 
(Pachyzna, Paleonictis). 

Ill. Lower Ypresian stage (beds of the London Clay, 
Herne Bay, Kyson, Harwich, Isle of Sheppey, in Eng- 
land; beds of Pourey near Reims in France). Fauna 
little different from that of the preceding stage. 

1. Local Evolution.—Continuance of Amblypoda (Co- 
ryphodon), and of Hyracotheriide (Hyracotherium). 

2. Migration of North American Origin of the Tillo- 
dontia (Platycherops — Esthonyx). 

IV. Upper Ypresian stage (beds of Teredo-sands, Ay, 
Cuis, Chavot near Epernay). 

1. Local Evolution.—Continuance of Insectivora (Ada- 
pisoriculus), of aberrant Primates (Plesiadapis), of Creo- 
donta-Mesonychide (Hyznodictis—Dissacus), and of 
Hyracotheriide (Propachynolophus). 

2. Important Migrations, Probably of North American 
Origin, of the mesodont Primates (Notharctide, genus 
Protoadapis), of the Rodentia-Pseudosciuride (Dectica- 
dapis), and Sciuride (Plesiarctomys), of Lophiodontide 
(parallel branches Lophiodon and Chasmotherium), of 
the Paridigitate Suillines (Protodichobune) and perhaps 
of Titanotheride (Brachydiastematotherium). 

This horizon is marked by some important migrations 
and great changes in the mammalian fauna, in conse- 
quence of which the latter approximate more closely to 
the fauna of the middle, than to that of the lower Eocene. 

V. Lutetian stage, two successive faune: 

(a) Lower and middle Lutetian (beds of Atgenton, 
of Bracklesham and part of the ‘‘terrain sidérolithique’’ 
of Egerkingen and of Lissieu). 

_ Local evolution of Lophiodontide (Lophiodon, Chasmo- 
therium), of Hyracotheriide (Pachynolophus, Propaleo- 
therium) and of Dichobunide (Meniscodon, Dichobune). 

(b) Upper Lutetian (‘‘Caleaire grossier’ beds of 
Paris: Nanterre, Vaugirard, Gentilly; Coucy, Dampleix; 
of Buschweiler, of Issel; les Matelles, St. Gily du Tese; 


No. 494] THE TERTIARY MAMMALS 113 


the larger part of the ‘‘terrain sidérolithique’’ of Eger- 
kingen and of Lissieu). 

1. Local Evolution.—Continuance of Lophiodontida 
(Lophiodon, Chasmotherium), of Hyracotheriide (Pachy- 
nolophus, Propaleotherium, and intermediate forms lead- 
ing to Lophiotherium), of Creodonta-Oxyclenide (Pro- 
viverra), of Rodentia-Sciuride (Plesiarctomys), of 
Dichobunide (Dichobune, Mouillacitherium), and of the 
mesodont Primates (Cznopithecus, ? Adapis). 

2. Important Migrations of Unknown Origin of the Pa- 
leotheriide (appearing suddenly with their two branches 
Palxotherium and Plagiolophus), the Anchilophide 
(Anchilophus), the Suide (Cheeromorus, Acotherulum), 
the Anthracotheriide (Catodontherium n. g., forerunner 
of Brachyodus), the Dacrytheride (Dacrytherium), the 
Xiphodontide (Xiphodontherium), the Dichodontide (Di- 
chodon, Tetraselenodon, Haplomeryx), some Sciuride 
(Sciurus), the Talpide (Amphidozotherium), the Erin- 
aceide (Neurogymnurus). 

3. North American Migrattops of the Hyznodontide 
and probably of the I i pt phide (Ne- 
erolemur). 

VI. Bartonian stage ae deposits of St. Ouen 
near Paris) of Sergy (Aisne), sandstones of Castrais 
(Lautrec, Mazou, Viviers, Montespien, etc.), of Robiac 
(Gard), ‘‘terrain sidérolithique’’ of Heidenheim and part 
of those of Mormont; very small part of the phosphorites 
of Quercy. 

1. Local Evolution.—Continuance of Lophiodontide 
(last of Lophiodon and Chasmotherium), of Hyraco- 
theriide (primitive representatives of Lophiotherium), 
of Paleotheriide (numerous parallel branches), of An- 
chilophide (Anchilophus), of Anthracotheriide (Catodon- 
therium n. g.), of Suidæ (Choeromorus, Cheropotamus), 
of Xiphodontide (Xiphodontherium), of Creodonta 
(Hyenodon), of Sciuride A of Adapidæ 
(Adapis). 


114 THE AMERICAN NATURALIST [ Von. XLII 


2. Migration, perhaps of North American Origin, of 
the Chalicotheriide (Pernatherium). 

-© VII. Ludian stage, two successive faune: 

(a) Lower Ludian (deposits of Saint Hippolyte de 
Caton (Gard), of Hordwell (Isle of Wight), lower strata 
of the Gypse de Paris; part of the Quercy phosphorites. 

1. Local Evolution.— Continuance of Paleotheriide, of 
Hyracotheriide (last of Lophiotherium), of Anchilophide, 
of Suide (Chcropotamus, Cebocherus), of Dacrytheride 
(Dacrytherium), of Xiphodontide (Amphimeryx), of 
Dichodontide (last of Dichodon), of Anthracotheriide 
(Catodontherium), of Hyznodontide (Hyzenodon, Quer- 
eytherium), of mesodont Primates (Adapis) and Anap- 
tomorphide (Microchcerus). 

2. No new migration known. 

(b) Upper Ludian (Gypse de Montmartre, deposits of 
Gargas, of Mornoiron, of Villeneuve la Comptal; of the 
Bembridge beds and the Headon beds in England; part 
of the phosphorites. 

1. Local Evolution.—Continuance of Paleotheriide, of 
Anchilophide (last of Anchilophus), of Xiphodontide 
(Amphimeryz, Xiphodon), of Dacrytheride (last of Da- 
erytherium), of Anthracotheriide (first representatives 
of Brachyodus, earliest Anthracotherium), of Suid (last 
of Acotherulum, Cheropotamus, and Cebocherus), of 
Dichobunide (last of Dichobune), of Hyznodontide (Hyæ- 
nodon, Pterodon), of Sciuride (Plesiarctomys, Sciurus), 
of Adapide (last of Adapis), of the Lemuroidea (last 
of Necrolemur). 

2. Migrations of Unknown Origin of the Anoplotheride 
(Anoplotherium), of the Cenotheride (Oxacron—= Hye- 
gulus), of the Canide (Cynodictis), of the Rodentia-The- 
ridomyide (Theridomys), and Myoxide (Myoxus). 

3. American Migration of the Marsupial Didelphyide 
(Peratherium). 


(To be continued.) 


ZOOLOGICAL PROGRESS * 


PROFESSOR G. H. PARKER 


HARVARD UNIVERSITY 


Tur chase, the domestication of animals, and the prac- 
tise of animal sacrifice in religious ceremonies were all 
customs of primitive man that led to an acquaintance 
with animal structure and habit long before human knowl- 
edge could be said to be organized. In the early steps of 
this organization, what we now know as zoology -was a 
part of natural history, but in the specialization of mod- 
ern times zoology has grown to the dignity of an inde- 
pendent science with numerous subsciences. In fact 
modern specialization has gone so far that concern has 
been frequently expressed lest the natural unity of science 
be entirely lost sight of; but, in sketching the outline of 
zoological progress, I hope to show you that, so far as 
zoology is concerned, this fear is unfounded. 

Any outline of the course of zoological progress must 
be somewhat in the nature of an inventory of zoological 
possessions, and I can not do better in beginning this brief 
survey than to call your attention at once to the real ma- 
terials of zoological research. These are the individual 
animals, which, as you well know, are not immensely di- 
verse, but show certain agreements whereby they may be 
arranged in groups whose members have similarity of 
form and habit and show the remarkable trait of produ- 
cing new individuals of like kind. These natural groups 
or species afford a basis for a descriptive inventory of the 
animal kingdom, and the attainment of such a complete 
description has been perhaps one of the most persistent 
motives to zoological work. 

Progress in this undertaking is indicated by the in- 
crease in the number of species described at each succes- 


1 An address delivered at The College of the City of New York. 
115 


116 THE AMERICAN NATURALIST [Vou. XLII 


sive period. Aristotle, who is usually regarded as the 
father of natural history and who lived in the fourth cen- 
tury B. C., mentioned in his zoological treatises about 480 
kinds of animals. Linnzus, in the tenth edition of his 
‘Systema Nature,’’ published in 1758, described 4,378 
species. Günther estimated that in 1830 a total of 73,588 
species had been reached and that in 1881 the.number had 
mounted to 311,653. Sharp placed the total in 1896 at 
386,000, and, judging from the rate of increase in the 
vertebrates and echinoderms, the total number of de- 
scribed species at present must be approximately 500,000. 
From these estimates, which include only living species, it 
must be clear that in the twenty-two centuries between 
Aristotle and Linnzus the number of species known to the 
naturalist had increased only ten-fold, while in less than 
a century and a half after Linneus the increase had been 
over a hundred-fold. 

This enormous increase has been the result of two proc- 
esses: the actual discovery of new forms in nature and 
the subdivision of what was originally regarded as one 
species into two or more species. The actual discovery 
of new forms implies the gradual exhaustion of nature 
and the conclusion of this process will come when explora- 
tion can yield no more new species. That the naturalist 
even of to-day is far from this goal is only too well known 
and can be illustrated by the following instances. 

All of you doubtless have seen a delicate pearly shell, 
chambered somewhat like a miniature nautilus, but with 
its whorls open. This shell, which is known as the 
Spirula, is found commonly on the shores of the tropical 
oceans and may even reach our more northern coasts. It 
is extremely fragile and hence it can not last long on a 
surf-beaten shore. Nevertheless it is sometimes so abun- 
dant on tropical beaches as to form veritable windrows. 
Each shell is the life product of a single Spirula animal, 
which, so far as one can judge from the abundance of 
shells, must be a common inhabitant of the tropical seas. 
And yet, aside from fragments, the Spirula animals thus 


No. 494] ZOOLOGICAL PROGRESS 117 


far obtained number only six. The first was collected in 
New Zealand and dissected by Sir Richard Owen. The 
second, for which no locality is known, was purchased 
by the British Museum from a dealer and dissected also 
by Owen. The third was collected near Port Jackson, 
Australia, and is now preserved in the Sydney Museum. 
The fourth was dredged near New Guinea by the ‘‘Chal- 
lenger’’ and was studied by Huxley and Pelseneer. The 
fifth was taken by the dredge in the West Indies by the 
United States steamer ‘‘Blake,’’ and the sixth was 
caught near Sumatra in a deep-sea net by the German 
expedition on the ‘‘ Valdivia.’’ If an animal as common 
as the Spirula must be, is known only by some six speci- 
mens, what a host of rare and undescribed species the 
ocean must contain. 

Not only are the ocean basins treasure stores of unde- 
scribed species, but the land areas are also far from ex- 
hausted. It would seem fair to have presumed that of the 
terrestrial quadrupeds certainly all the larger and more 
striking species had been described, and yet, since the 
opening of the new century, a large cloven-hoofed mam- 
mal in general appearance somewhat between a donkey 
and a giraffe has been discovered in the Semliki forests 
of central Africa. This remarkable mammal was sought 
for in 1900, at first unsuccessfully, by Sir Harry John- 
ston, who finally succeeded in obtaining a skin and a 
skull from which the animal was described by Lankester 
in 1902. The natives call it okapi and report it by no 
means rare, and yet it remained almost to the present 
time without being known to science. But the naturalist 
is not obliged to search the deep sea or to journey to 
central Africa for new species. There is hardly an order 
of insects that could not be enriched with new forms by 
a season’s collecting even within the limits of New York 
City, and it must therefore be evident that the half-million 
of species now described is only the beginning in the in- 
ventory of nature’s stores. 

In addition to the discovery of new species in nature, 


118 THE AMERICAN NATURALIST [Vou. XLII 


the process of splitting what was assumed by the older 
zoologists to be a valid species into two or more new ones 
has also considerably increased the number of described 
forms. This practise, though sometimes questionable, is 
at least illuminating, for it raises at once the fundamental 
question of what constitutes a species. In the days of 
Linneus when special creation was more generally ad- 
hered to than now, it was comparatively easy to meet this 
question by the statement that a species is the aggregate 
of individuals represented by the originally created pair 
or stock and their descendants; but, with the acceptance 
of the evolutionary idea, this reply no longer sufficed. 
From the evolutionary standpoint every species has had 
a history and this history has been clearly one of change 
whereby the aggregate of more or less similar individuals 
at one time representing the species gave rise to the self- 
perpetuating stock whose more remote members evolved 
in one or more directions new features, so that the species 
either as a whole assumed new characteristics or split into 
two or more subordinate groups, each having its own 
special features and being destined eventually to become 
as well ci ibed from its next of kin as the original 
stock was at the outset. With this process in mind it is 
fair to expect that nature would be found to embrace 
many aggregates of individuals which would represent 
species at all steps of differentiation, and whether the 
individuals of a given aggregate had come to differ suffi- 
ciently among themselves to constitute a new species or 
not would depend entirely on the judgment of the natural- 
ist who described them. It is thus clear that we can not 
expect any fundamental characteristic by which a new 
species can be definitely determined, for it is obvious that 
the transformation of species is a more or less continuous 
process in which the degree of separation whereby the 
new species will be established is somewhat arbitrarily 
determined by each describer. Hence the idea of species 
rests upon an artificial basis, and, if the describer’s meas- 
ure of specific difference diminishes with the progress of 


No. 494] ZOOLOGICAL PROGRESS 119 


time, it is perfectly legitimate to subdivide previously 
described single species into smaller aggregates to be 
denominated new species. 

Where this movement will lead to is not easy to fore- 
tell. It was hoped that the statistical methods of bio- 
metric work would make possible a solution of some of 
the difficulties in defining species, but, while these methods 
enable the investigator to discover and express differences 
between large groups of individuals vastly more accu- 
rately than the old methods of simple inspection and 
rough mental estimate did, they do not settle what char- 
acters or how many such shall be used in defining a spe- 
cies or what degree of difference must be arrived at 
before a given aggregate may be divided into two or more 
species. Nor does the recent proposition of de Vries come 
nearer to solving the problem. According to this investi- 
gator real species can be defined by a certain combination 
of characters which vary not in a continuous way but by 
leaps. These discontinuous variations constitute differ- 
ences that may be as distinct as the differences between 
chemical elements ; and any real or elementary species, as 
de Vries designates it, is distinguished by one or more of 
these elementary characters. Such elementary species, 
though open to variation, are cut off absolutely in their 
specific characters from other such species by a gulf 
that is never bridged by intermediate forms. Hence 
they ought to be as easily and distinctly describable as 
chemical compounds or even chemical elements. These 
elementary species, which have been for the most part 
heretofore ignored or passed over simply as races, etc., 
are the real units of systematic zoology and are much 
more numerous than the ordinary or Linnean species. 
In fact, each Linnean species probably consists of many 
elementary species and consequently the acceptance of 
this proposition would multiply the number of described 
species many times. But the difficulty with this proposal 
is to be found in the fact that an inspection of the so- 
called elementary characters shows them to be not so 


120 THE AMERICAN NATURALIST [ Vou. XLII 


stable as de Vries assumed. In some characters, like coat 
colors, fixity is more or less realized; but in other fea- 
tures, particularly dimensional ones, such an amount of 
variation is shown that the resulting forms necessitate the 
same artificial methods of separation as those to which 
the older systematists were obliged to resort. From a 
radical standpoint there seems to be no escape from the 
view that a species is at best an imperfectly definable 
aggregate of more or less similar individuals and that 
this conception rests upon an artificial basis. 

Although the idea of species must be admitted to be 
artificial rather than natural, its immense practical im- 
portance is not to be lost sight of; for, as a tool in the 
hands of the working zoologist, it is absolutely indispen- 
sable. Moreover, the arrangement of species into related 
groups and the development thereby of a system of classi- 
fication has led to views on animal phylogeny of the ut- 
most significance. That living animals range from the 
relatively simple unicellular protozoans to the immensely 
complex vertebrates suggests at once that the modern 
faunas include not only the latest products of animal 
evolution but many remnants of the remote past. This 
state of affairs is a continual temptation to picture the 
past history of the animal kingdom in terms of modern 
forms and to assume, for instance, that the protozoans 
of to-day are like the primitive protozoans from which 
the higher animals have been derived. This attitude leads 
to the discussion of the so-called affinities of the modern 
groups, a practise that in my opinion is open to the 
objection of attempting to make parents and grandparents 
out of brothers and sisters. How futile this practise is 
can be seen in such a group as the reptiles. You are 
doubtless aware that the modern reptiles are included in 
four orders: the chelonians, or turtles; the crocodilia; the 
rhynchocephalia, represented by a lizard-like reptile from 
New Zealand; and the squamata, or lizards and snakes. 
You are probably not so well aware that. the class of 
reptiles also includes five other orders, all fossil, among 


No. 494] ZOOLOGICAL PROGRESS 121 


which are to be found some of most specialized and pro- 
digious land and water animals known. No possible con- 
sideration of the recent orders of reptiles would ever lead 
one to suspect the remarkable nature of these ancient 
forms, and the so-called affinities of the recent orders 
become meaningless in the light of the true ancestral 
relations as seen in the past history of the group as a 
whole. Tempting as the field of speculative phylogeny is, 
its results can never be of much value till they receive the 
endorsement of actual history as traced in fossil ancestry. 
In this connection I can not do better than quote a short 
passage from Huxley, who, as you well know, was an 
ardent student of fossil as well as living animals. In his 
essay on ‘‘The Advance of Science’’ he says: 

A classification which shall represent the process of ancestral 
evolution is, in fact, the end which the labors of the philosophical 
taxonomist must keep in view. But it is an end which cannot be 
attained until the progress of paleontology has given us far more 
insight than we yet possess into the historical facts of the case. 

It is plain that the history of the animal kingdom is to 
be sought for not through ingenious speculations on the 
recent groups of animals, but by the persistent and patient 
exploration of the fossil-bearing rocks. 

Although the study of animal genealogy, as outlined by 
fossil remains, is a relatively novel field, it has already 
yielded certain general results worthy of careful atten- 
tion. It is customary at present to group all species of 
animals under some ten or twelve main divisions or phyla 
of the animal kingdom. These phyla have doubtless been 
evolved from some common group of animals in the 
remote past, and consequently, in tracing back their his- 
tory as represented by fossil forms, it is not unreasonable 
to expect that their lines would gradually converge toward 
this common ancestral stock. In some instances, like the 
flat-worms, the phylum is known only through its modern 
representatives, and these representatives are of such 
consistency that it is not surprising that none of these 
animals have been preserved in the fossil state. But, 


122 THE AMERICAN NATURALIST [ Vou. XLII 


aside from cases of this kind, all phyla that might be rep- 
resented by fossils are, as a matter of fact, so represented ; 
and the remarkable feature of this representation is that it 
does not show a convergence toward a common stock, 
but the phyla as such were as distinct in these early times 
as they are to-day. This state of affairs, which at first 
sight seems contrary to the evolutionary idea, is due in 
all probability to a universal destruction by extensive 
rock metamorphosis of the earliest of animal remains, 
and we are therefore probably correct in concluding that 
fossils at best give us only the later chapters in the evo- 
lution of the animal kingdom. Within a phylum the main 
lines of descent can sometimes be clearly discerned, but 
between phyla there are no absolutely certain connections, 
nor is there as a matter of fact a single completely ex- 
tinct phylum known. These facts lead us to see that for 
an immensely long period the main divisions of the animal 
kingdom have been as they are at present and that the 
genetic connections of the phyla, which would be discern- 
ible with certainty only through their fossil remains, are, 
in ‘consequence of the absence of these, probably abso- 
lutely and irrecoverably lost. Even the important sug- 
gestions that embryology has yielded as to the phylogen- 
etic relations of the chief animal groups must remain 
forever hypotheses because of this irreparable blotting 
out of past records. 

Although the systematic zoologist may look upon the 
animal kingdom as composed of imperfectly definable 
aggregates of individuals whose relations in the remote 
past are irretrievably lost but whose numbers are such 
as to occupy his labors for many years to come, his arrival 
at this conception has been over a course that has brought 
to view such a multitude of new prospects that the real 
extent of zoology is only now beginning to be dimly seen. 
These more recently acquired territories, which are now 
being cultivated with a vigor no less than that bestowed 
in past times almost exclusively on systematic zoology, 
must now be looked into. It is somewhat difficult for us 


No. 494] ZOOLOGICAL PROGRESS 123 


to conceive of the state of mind of the zoologist of a cen- 
tury ago so far as his conception of the structure of ani- 
mals is concerned. To him they consisted of organs com- 
posed of a variety of unrelated substances, such as 
muscle, membrane, bone, fat, blood, etc., which consti- 
tuted the elementary materials of the animal body. It was 
therefore a great step forward when Schwann showed in 
1839 that animals; like plants, were composed of struc- 
tural units or cells whose physiological significance, as 
Briicke afterwards pointed out, entitled them to the name 
of elementary organisms. Many lower animals, belong- 
ing to what are now called the Protozoa, proved to be 
single cells, while the higher animals in all cases were 
found to be multicellular. The number of cells entering 
into the formation of the body of one of these higher 
animals is truly enormous. It is impossible to get re- 
liable statements for these numbers in any single complex 
animal, but a recent careful estimate of the number of 
ganglion cells in the human cerebral cortex places the 
total at 9,200,000. As this enormous number of cells 
would occupy less than a cubic inch of space, one can 
form some rude conception of the prodigious number in 
the whole human body. 

It is a remarkable fact that almost all cells, whether 
they are whole single animals or only parts of animals, 
are of small size. There seems to be something about the 
organization of a cell which ordinarily prevents it from 
enlarging much beyond microscopic proportions. The 
essential parts of a cell are its nucleus and the surrounding 
cytoplasm, and the continued activity of the cytoplasm is 
known to be dependent upon the presence and integrity 
of the nucleus. Such being the case it would seem as 
though the nucleus could administer to only a limited 
volume of cytoplasm and thus restricts the size of the cell. 
Apparently, however, this relation is one of volume and 
not of distance from the nucleus, for the cytoplasm of a 
ganglion cell may be drawn out into a most delicate nerve- 
fiber process that may reach half the length of the human 
body. : 


124 THE AMERICAN NATURALIST [Vou. XLII 


The arrangement of the cells in the body of a multi- 
cellular animal is not, as in most plants, of a more or 
less promiscuous kind, but conforms to certain funda- 
mental principles. Among these probably the most im- 
portant is one that depends upon the fact that animals 
assimilate solid food. To carry out this operation they 
possess almost universally a digestive cavity into which 
this solid food is carried and there rendered soluble. The 
only multicellular animals that do not possess a digestive 
cavity are certain parasites, like the tapeworm, whose 
modes of life are such as to make digestive organs super- 
fluous. In the simpler multicellular forms, the coral ani- 
mals, etc., the whole animal is sac-like in structure and 
may be briefly described as an animated stomach. Not 
only is this state characteristic of such primitive forms, but 
in the development of almost every multicellular animal 
known, the first organ to be formed is the digestive organ. 
This is brought about in that the cells, which are destined 
for the future animal’s body, become arranged in the 
form of a two-layered sac in which the inner layer or 
entoderm bounds the digestive space and the outer one 
or ectoderm acts as a protective covering. Both layers 
develop a certain amount of muscular tissue and this is 
brought into action through external stimuli that from 
the nature of the case are received usually by the ecto- 
derm. Hence this layer becomes the seat of those changes 
which in the higher animals eventually shape themselves 
in the sensory and nervous organization of these forms, 
while the entoderm is concerned with the digestive func- 
tions. Between these two layers there develops in all 
the higher multicellular animals a third layer, the meso- 
derm, which, as has been intimated, is primarily muscular 
in character but may also give rise to the internal skele- 
ton, circulatory system, and other related sets of organs. 
Thus the body of a multicellular animal is composed of 
definite layers or masses of cells, chiefly three in number, 
with which special functions or modes of activity have 
become firmly associated. 


No. 494] ZOOLOGICAL PROGRESS 125 


Although these cell layers as such retain their limits in 
a most striking and clear way in the bodies of the higher 
animals, they must not be thought of as independent or in 
any sense isolated in their development. Their mutual 
relations are often of a most intimate kind and in the 
course of their development these relations tend rather to 
become more firmly consolidated than the reverse. This 
condition is well illustrated by the growth of the neuro- 
muscular mechanism in animals, a growth that can be 
traced step by step through the multicellular forms till it 
finally shapes itself into the complex machinery whereby 
the animal reflexes are carried out. 

The first step in this process is seen in the sponges, 
which in some respects are the simplest of the multicel- 
lular animals. As is well known, these animals are quite 
as sluggishly responsive to stimulation as plants are. A 
long and unsuccessful search for their nervous organs has 
ended in the belief that they possess no such structures. 
Some of their cells, particularly in the neighborhood of 
their numerous pores, are elongated or even fibrous and 
are apparently contractile enough to serve as a means of 
closing these openings. It is highly probable that these 
contractile cells, which may be regarded as primitive 
muscle cells, are brought into action by some stimulus 
directly applied to them, such as dissolved materials in 
the sea-water, ete. We are so accustomed to think of 
muscle as controlled by nerve that independent action of 
this kind seems wholly anomalous. And yet it must not 
be forgotten that muscle can be made to contract by the 
direct application of a stimulus and that even in the 
higher animals under natural conditions this may occur. 
Steinach has shown that when bright light is thrown on 
the eye of a fish or an amphibian the pupil will contract 
even after all vestiges of nervous connections have been 
destroyed, and he believes this to be due to the direct 
stimulation of the muscle fibers by light. This case sup- 
ports the opinion that in sponges the contractile tissue 
responds to direct stimulation, and in my opinion the 


126 THE AMERICAN NATURALIST (Vou. XLII 


sponge represents the first step in the differentiation of 
the neuro-muscular mechanism, a step in which the pri- 
mary and fundamental character of muscle is disclosed in 
that this is the only constituent present. This self- 
sufficiency of muscle is also made evident in the rhythmic 
beat of the embryonic chick heart before nervous differ- 
entiation has taken place. 

In the sponges the primitive muscle cells lie either in 
the ectoderm or the subjacent mesoderm. In the coral 
animals, the jellyfishes, and their allies, the muscle cells 
occur in the deeper parts of the ectoderm and entoderm, 
a position where a forming mesoderm might be expected. 
It is usually stated that in the higher animals the muscles 
are derived from the mesoderm, and in individual devel- 
opment this is true, but from a phylogenetic standpoint 
I believe the reverse to be the case, namely, that the meso- 
derm has come from muscle and that the first step in the 
real origin of this layer is indicated in the migration of 
the muscular tissue of the ccelenterates or other like forms 
from the ectoderm or entoderm into the region between 
these two layers. This operation, which involves both 
layers in many of the lower animals, is usually limited in 
the higher forms to the entoderm, probably because this 
layer is the one which by reason of its proximity to the 
digestive cavity can best supply material for future 
growth. But, however this may be, it seems to me prob- 
able that the mesoderm has had its origin in the process 
of muscle formation, a process that is seen in its incip- 
iency in the celenterates. That the mesoderm is also 
concerned with providing mechanical support for the ani- 
mal is obvious, but in my opinion its contractile function 
is the primary one. 

It cannot be stated with certainty at present that in 
the normal action of cclenterate muscle this tissue is 
stimulated directly, though the investigations of Loeb 
on the jellyfish, Gonionemus, show beyond a doubt that 
such a method of stimulation is possible. It is, however, 
well established that in many jellyfishes muscle action is 


No. 494] ZOOLOGICAL PROGRESS 127 


under the influence, if not the control, of nerves, and these 
cases represent, so to speak, the second step in the differ- 
entiation of a neuro-muscular mechanism. In such jelly- 
fishes, groups of cells especially open to stimulation by 
light, pressure, ete., occur on the edge of the bell, and from 
these sense bodies nerve fibers pass to the muscular sheet 
on the under face of the bell. These sense bodies evidently 
act as triggers by which the muscular mechanism can be 
brought into action and in that way render it more deli- 
cately responsive than if it relied entirely upon direct 
stimulation. The relation of such a system may be de- 
scribed as that of a set of sense organs directly connected 
with a musculature, for there is nothing here that can be 
fairly described as a central nervous organ. As the sense 
organs are in the ectoderm and the muscles represent in- 
cipient mesoderm, it is obvious that the future develop- 
ment of these two layers will in this respect be most 
intimately bound together. 

The last organ, in my opinion, to appear in this chain 
of development is the central nervous organ, the brain 
and its subordinate centers. This originated on the line 
of connection between the sense organ and the muscle, 
but rather from the sensory than the muscular end, as is 
shown by its anatomical relations in adult animals and 
by its invariable origin in the embryo from the ectoderm. 
It is scarcely recognizable in the simple multicellular ani- 
mals and begins to be an obvious organ in such inter- 
mediate forms as the worms. Here it serves chiefly as a 
means of freer and more extended communication between 
the sense organs on the one hand and the musculature on 
the other, and thus lays the foundation for the marvelous 
development that it shows in the higher animals, where, as 
a storehouse of race and individual experience, its sig- 
nificance is unparalleled. The paramount importance of 
the brain in fact is so fully recognized that it is usual to 
treat the sense organs as appendages of it, but, if the 
view that I have advanced is correct, just the reverse is 
true; the sense organs of a bilaterally symmetrical animal 


128 THE AMERICAN NATURALIST [ Vou. XLII 


are clustered at its anterior end not because the brain is 
there but because this is the end of the animal most likely 
to receive stimuli, and the brain is at this end because it 
has developed from this sensory equipment. The brain, 
in other words, is the appendage of the sense organs. 

In tracing thus the growth of the three elements of the 
neuro-muscular mechanism, the muscle, sense organ, and 
brain, I have endeavored to keep before you their rela- 
tions to those primitive organs, the ectodermic and ento- 
dermic cell layers, and to make clear to you how these 
cell layers come to be part and parcel of this growth. This 
subject might have been illustrated by any other set of 
organs than those concerned with the neuro-muscular 
mechanism; thus it is well known that the skeleton has 
been differentiated chiefly under the influence of the 
muscles, and that the digestive apparatus is as intimately 
associated with the differentiation of the circulatory or- 
gans as these are with the respiratory and excretory sys- 
tems. But to discuss such relations even in a brief way 
would trespass too much on our present time, and I must 
therefore pass them by. Suffice it to say that in the main 
these relations constitute that province of zoology called 
by Goethe morphology, which includes the fundamental 
aspects of the form of adult and developing animals and 
which has been a field that for a century past has elicited 
the keenest interest from some of the most profound 
masters of zoology. 

No one who has become deeply interested in morpho- 
logical problems can have proceeded far without fre- 
quently meeting questions of a physiological nature. To 
answer these the simple observational methods of the 
past are insufficient, and it is necessary to resort to ex- 
perimental procedure such as has been for a long time the. 
practice of chemists and physicists. From this stand- 
point one enters what may be regarded as the most recent 
field of zoological research. Since the elementary sub- 
stances of the animal body are the same as those of the 
inorganic world and since the stream of energy flowing 


No. 494] ZOOLOGICAL PROGRESS 129 


through that body conforms in large measure to prin- 
ciples already discovered in the physical and chem- 
ical laboratories, it has been generally assumed that the 
life processes of an animal are nothing more than com- 
plex examples of physico-chemical interaction. This idea 
has proved most stimulating in its effect on research, but 
to what extent it will be found true can not at present be 
stated. It is quite possible that the chemist and physicist 
have as much of a fundamental nature to learn from living 
material as they have already gained from lifeless sub- 
stance. 

The paramount influence of material in animal reac- 
tions can not better be illustrated than in such processes 
as inheritance. It is well known to you how much more 
closely on the average offspring resemble their parents 
than they do other members of their own species, and 
you are familiar with the long persistence of certain 
family traits. These resemblances are explained by the 
fact that the offspring start from a certain amount of 
living substance contributed by each parent, but the pow- 
erfully determinative qualities of this substance are only 
to be appreciated in certain cases. It is well known that 
in human beings there are two classes of twins, identical 
twins and ordinary twins. The latter come from two sep- 
arate eggs and may vary as much from each other as any 
two members of the same family. The former come from 
a single egg which by some accident has become separated 
into two parts. Identical twins are always of the same 
sex and are often so alike in features and actions that 
they are almost indistinguishable even to their near asso- 
ciates. Their close similarity, which may amount almost 
to identity, shows that the substance from which they 
both came has developed in a most rigidly uniform way 
and indicates that the development of ordinary twins, as 
well as of other individuals, is probably also closely lim- 
ited from the beginning, but the degree of this limitation 
is not discoverable in these cases, for we have no basis 
of comparison. Since living material can thus duplicate 


130 THE AMERICAN NATURALIST [ Vou. XLII 


itself in product, its significance in inheritance can not 
well be overestimated. 

Not only may physical features be accurately inherited, 
but the capacity to perform various complex sets of ac- 
tions may be transmitted with great precision. It is diffi- 
cult if not impossible for us to state the exact source of 
many of our modes of actions. We inherit much and we 
learn much, and whether in a given complex act we are 
dealing with an inheritance or a new acquisition or a 
mixture is not always easy to state. With certain lower 
animals this question is perhaps more readily decided. 
Bees have the capacity of building a truly wonderful 
structure, the comb, which, because of economy of ma- 
terial and accuracy of workmanship, has long been an 
object of admiration. Is this complex activity inherited or 
learned by imitation? To answer this question, Kogev- 
nikov reared some bees from a comb placed in an empty 
hive. After the bees had hatched and got their strength 
they proceeded without having seen other bees at work to 
make a comb that was as perfect as one made under ordi- 
nary circumstances. It might be objected that they had 
seen the comb from which they themselves had hatched, 
and this must be admitted to be so; but this fact is prob- 
ably without significance, for they made perfectly typical 
queen cells the like of which they had never before seen. 
It is thus evident that not only structural peculiarities but 
highly complex activities can be inherited. 

The means of this inheritance has already in a measure 
been made out. When a common protozoan, like Para- 
mecium, reproduces, the parent body divides into ap- 
proximate halves. Each of the two offspring receives not 
only a large portion of the parental substance but a cer- 
tain number of cilia and other parts directly from the 
parent, and hence that the offspring should resemble the 
parent is not very surprising. When, however, reproduc- 
tion in the higher multicellular animals is examined a 
somewhat different condition is discovered. Sexual re- 
production is accomplished by means of a fertilized egg, 


No. 494] ZOOLOGICAL PROGRESS 131 


which consists of a mass of cytoplasm chiefly from the 
maternal side, a centrosome from the paternal side, and 
usually an equal number of chromosomes from each side. 
As the offspring may resemble both father and mother, 
it follows that the substance that is the vehicle of inheri- 
tance is very probably the material of the chromosomes, 
the chromatin. This chromatin carries from parent to 
child not the vestige of an organ and is inconceivably 
small in amount. The human egg cell is approximately 
a sphere with a diameter of about 0.2 of a millimeter, and 
with a specific gravity about that af water; consequently 
its weight is about 0.004 of a milligram. The volume of 
the chromatin of a fertilized mouse egg, as measured for 
me by Mr. J. A. Long, is somewhat less than one-thou- 
sandth of the volume of the whole egg, and, assuming 
that this proportion holds for the human egg, and that its 
chromatin has about the same specific gravity as water, 
the weight of this chromatin would be about 0.000,004 of 
amilligram. Yet this mere trace of material can influence 
the adult substance of two identical twins to such an ex- 
tent that their bodily configuration and actions are 
scarcely distinguishable. If we estimate their combined 
weights to be 130 kilograms, the chromatin of the egg 
from which they came can be said to have influenced in 
this profound way 32,500,000,000,000 times its original 
weight. Of course it must be borne in mind that the chro- 
matin of the egg is living and that in the growth of the 
individual it assimilates and thereby increases in vol- 
ume; the chromatin is not spread through the growing 
body in ever-increasing dilution. But, even granting this, 
its precision in the transmission of characteristics is cer- 
tainly most remarkable; for when it is derived from a 
single source, as in identical twins, its effect upon the 
growth of the two individuals is to make them most 
strikingly alike. It is important to observe that the chro- 
matin of at least certain male cells is composed very 
largely of nucleic acids, and that it is therefore very 
probable that the chemical composition and structure of 


132 THE AMERICAN NATURALIST [Vou. XLII 


these substances are intimately concerned with heredity. 
This discussion makes clear how extremely important ' 
certain materials are to the body and yet how impossible 
it is at this stage of scientific progress to frame any clear 
and consistent conception of the method by which these 
materials exert their influences. 

If such relatively simple physiological questions as 
this concerning the material basis of heredity meet with 
difficulties such as I have pointed out, how vastly more 
intricate and perplexing must be the problem of the rela- 
tion of the living materials of animals’ bodies to their 
nervous and mental states. That such a relation exists is 
well recognized, but what this relation is will probably 
require many years even to outline. 

It is in the direction of comparative physiology that 
the more important new advances in zoology are to be 
made. In my opinion zoology will meet with an expan- 
sion in this century quite as much as the study of elec- 
tricity has in the last hundred years. When Franklin 
tried his hazardous experiment with lightning, no one 
suspected that he was dealing with a factor that could 
come to be of such paramount importance in every-day 
affairs as electricity has become, and it seems to me 
probable that the zoologist of to-day is working obscurely 
with problems that will eventually lead to revolutionary 
results. I have already pointed out the importance of 
certain minute quantities of material in inheritance, and 
the significance of this in animal breeding and in social 
problems must be evident. But in a thousand other ways 
the doings of animals are worthy of closest attention. 
Many of the most difficult problems that the human race 
has attacked have already found their solution among 
the lower animals. Secure aerial transportation, which 
is almost a dream with us, is an accomplished fact among 
many animals. Our own efforts are not so safe if they 
are more extensive than those of a flying fish. They are, 
however, by no means equal to those of a bat or an insect, 
and they are immensely inferior to those of a bird. Our 


No. 494] ` ZOOLOGICAL PROGRESS 133 


systems of artificial illumination are regarded by us as 
one of the many evidences of advanced civilization and 
yet our best products are ridiculously poor compared with 
those of the lower animals. Gas or other such luminants 
yield at best something less than one per cent. light, the 
remainder of the energy being dissipated as waste heat, 
and our most successful means of illumination scarcely 
reach fifty per cent. of efficiency. The radiant energy of 
the luminous organ of a fire-fly is all light, and none is 
wasted as heat. Were the processes of this organ under- 
stood and made applicable to daily life, they would at once 
sweep out of existence every illuminating plant known. 
Such a revolution as this suggests awaits only the advance 
of zoological science, and, as I have said, this may be 
looked for in the near future. To my mind it affords one 
of the brightest outlooks for zoological investigation. 

Thus far I have scarcely touched on what has been 
for so long a time the rallying word in biological work, 
evolution. But, if we knew the physiological workings of 
the animal body, especially in relation to inheritance, etc., 
evolution would be in large part understood and the lines 
of work that have just been recalled would be only ex- 
amples of evolutionary processes. The most promising 
recent change in the study of evolution, a change which 
we owe largely to de Vries, is the discovery that evolution 
as now understood is probably going on before our eyes 
and at a measurable rate; hence it is open to observational 
and experimental treatment and we may expect renewed 
and rapid growth in the near future for this line of work. 

Many of the unexplored regions touched upon in this 
survey are of such magnitude that few can hope to be 
their conquerors, but all may aid in preparing the way. 
In invading these new regions former methods and means 
will be sure to be found insufficient; the help of kindred 
sciences, such as physics and chemistry, must be called 
upon. This appears to bea sufficient answer to those who 
thought that they saw in the subdivision of zoology and 
of other sciences a step away from the true unity of sci- 
entific endeavor. 


NOTES AND LITERATURE 


HEREDITY 


The Possibility of Inheritance through the Placental Circulation 
instead of through the Germ Cells.—In the December issue of THE 
AMERICAN NATURALIST reference was made to Professor Bate- 
son’s explanation of the inheritance of hemophilia. Hemo- 
philia is a tendency to excessive bleeding, ascribed either to 
‘a peculiar frailty of the blood vessels or some peculiarity in the 
constitution of the blood.’’ It is seen far more often in males 
than in females, yet the males do not transmit it. Physicians 
are so confident of this as to recommend that ‘‘the daughters 
should not marry as through them the tendency is propagated.’’ 

Professor Bateson compared the inheritance of hemophilia 
with that of the horned condition in sheep. A hornless breed 
crossed with a horned form yields horned males and hornless 
females. The latter will transmit horns to their male off- 
spring only, unless again crossed with horned stock, when horned 
females will also appear. This analogy with hemophilia holds 
good in so far as the females transmit a condition which they 
do not present, and it suggests a possible explanation of the 
occasional manifestation of hemophilia in females. It fails, 
however, in an essential point. The horned male sheep transmit 
their condition whereas the hemophilie males do not. 

A different explanation is suggested by the studies on im- 
munity reviewed and supplemented by Dr. Theobald Smith." 
Ehrlich, as he states, found that female mice which had been 
made immune to certain toxic substances gave birth to young 
which were also somewhat immune. The immunity was soon 
lost and was never transmitted to the second generation. Im- 
mune males did not transmit any immunity to their offspring. 
Other investigators, using rabbits and guinea-pigs, have shown 
the transmission of several forms of immunity through the 
females only. 

The artificial immunity may perhaps be permanent in the 
parent guinea-pigs. It has lasted long enough to affect four lit- 
ters of one female, and Smith has records of ‘‘a considerable 

1 Smith, T. The degree and duration of passive immunity to diphtheria 
toxin transmitted by immunized female guinea-pigs to their immediate off- 
spring. Jour. of Med. Research, 1907, vol. 16, pp. 359-379. 

134 


No. 494] NOTES AND LITERATURE 135 


number of guinea-pigs which transmitted immunity for over 
a year.” One animal gave birth to a litter of immune young 
thirty months after receiving the immunizing injection. The 
immunity is not so well marked in the offspring, and Smith 
agrees with the general conclusion that the grandchildren of 
immunized females are never affected. 

Ehrlich found that in mice lactation plays an important part 
in the transmission of immunity to offspring, and that normal 
offspring may gain a considerable degree of immunity by being 
nursed by immune mothers. This conclusion requires confirma- 
tion, for Vaillard and Remlinger agree that, in guinea-pigs and 
rabbits, nursing from an immune mother does not confer im- 
munity.? Rosenau and Anderson? were able to exclude the 
milk as a factor in transmitting hypersusceptibility to serum 
injections by a series of ‘‘exchange experiments.’ In these ex- 
periments the offspring of a susceptible mother are given, im- 
mediately after birth, to a non-susceptible guinea-pig to nurse, 
and the young of the non-susceptible guinea-pig are placed with 
the susceptible mother. ‘‘From these exchange experiments we 
learn that the hypersusceptibility is not transmitted to the young 
in the milk.” 

Gay and Southard ‘ believe that the well-known susceptibility 
of guinea-pigs to a second dose of horse serum is due to an 
unisolated substance which they name anaphylactin. This is 
probably transmitted from the blood of the mother to that of 
her young through the placental circulation. It is contained 
in the serum of a guinea-pig two hundred and four days after 
the animal has been made susceptible by the first injection, and 
if from 1.5 to 2.5 c.c. of serum from such an animal are trans- 
ferred to a normal guinea-pig, the latter becomes susceptible. 
However, a transfer of serum from the second guinea-pig to a 
third does not produce susceptibility and this result corresponds 
with the observation that artificial immunity 1s inherited only 
by the first generation. 

It is possible that hemophilia is due to an abnormal chemical 
composition of the blood, such as produces its manifestations 
in the male rather than the female, owing to differences in metabo- 

2 Cited by Smith, loc. cit. 

* Rosenau, J., and Anderson, 
bility and immunity. Journ. of Med. 

‘Gay, F. P., and Southard, E. E 
pig. Journ. of Med. Research, 1907, vol. 16, p 


a 
J. F. Further studies upon hypersuscepti- 
Research, 1907, vol. 16, pp. 381-418. 
On serum anaphylaxis in the guinea- 
p. 143-180. 


136 THE AMERICAN NATURALIST [ Von. XLII 


lism in the two sexes. If its cause is a substance in the blood 
it may be ‘‘inherited’’ from the female alone, and the male 
which manifests the disease can not transmit it. Thus it would 
be a case of transmission through somatic elements rather than 
through the germ cells. 

Pol ks. 


INVERTEBRATE MORPHOLOGY 


Form Variation in Amblystoma tigrinum.—Powers* has observed 
the aquatic forms of this salamander both in their natural en- 
vironment and under artificial conditions. His paper contains 
a large amount of material of great interest which would be 
much clearer reading if the numerous observations and experi- 
ments had been more explicitly described as to objective point 
and methods employed. The paper is too long for condensation 
here, but a few of the results can be noticed and will be welcome 
to those interested in the axolotl question. He distinguishes 
two main types, the ordinary larve and the cannibals, both by 
habits and in important points of structure. Taking the ordi- 
nary form first, two types as a body form are recognizable: those 
with the habit of crawling about on the bottom in a sluggish 
manner and thus living largely in the dark, these are of a 
broader shorter form and are called the ‘‘robust type,’’ and a 
second type of quite different habit, being active swimmers going 
about actively in search of their prey, and of an elongate slender 
form, the ‘‘slender type.’ There is a great difference in the 
ratio of head width to total length in these two types, head 
width being contained 6.42 in total length in the robust type 
and 11 times in the slender ones. The mode of feeding is quite 
different in these two types. In the robust bottom-living forms 
food is obtained by using the mouth as a sieve and opening 
it widely to strain water through it in hopes of finding food 
thereby, with the result that the gape is increased. On the other 
hand, the slender swimming forms go about actively in search 
of prey, which, when they see it, they actively seize so that the 
mouth is not opened so widely as in the sieving process of the 
sluggish robust type. He also notes variations in special parts, 
such as the tail, the head and the posterior limb. Tails vary 

* Powers, J. H., 07. Morphological Variations and its causes in Am- 
blystoma jigri Studies from the Zoological Laboratory of the Uni- 
— of Nebraska, 71, pp. 1-77, pls. i-ix. 


No. 494] NOTES AND LITERATURE 137 


from broad to narrow, long to short, some are flat and some 
more rounded and tapering, thick and fleshy or thin. Heads 
vary in breadth, length, thickness, contour of muzzle, distance 
between nares, between eyes, size of gape of mouth. Hind limbs 
vary as to robustness or slenderness, rounded or flattened shape 
of toes and habitual position of limb with reference to body. 
The writer of the paper is inclined to refer most of the varia- 
tions which he finds directly or indirectly to the nutrition of the 
possessor. He says ‘‘excessive nutrition with these larve seems 
as it were to overflow into all the peripheral parts quite regard- 
less of function.’’ He shows very satisfactorily that the foot 
features which seem like aquatic life adaptations are not such 
in fact, but are due to over-nutrition. In swimming these forms 
do not use the foot; it lies idly alongside the body. 

The cannibal form of larve is very interesting and wholly 
novel. There are occasional larve which for reasons as yet 
unknown, and against the tendencies of most of the larve, have 
adopted the habit of feeding on their fellows. It was possible 
to convert some non-cannibal larve to the habit, while not even 
starvation would induce others to adopt it. Cannibals, a num- 
ber of photographs of which are shown, are characterized by 
the great over-development of the head and under-development 
of the body and tail. The changes came on rapidly after the 
habit had become established, a week showing very mark 
steps in that direction. The head enlargement includes internal 
as well as external anatomical changes, gill arches become more 
elongated, more numerous and much larger teeth develop in 
the palatine region; the entire head becomes more elongated, the 
brain more posterior in position, and, more strange still, it ‘‘is 
easily seen through the soft palate . . . and is of a less com- 
pact and more piscine type.’’ All these points need fuller and 
more detailed description and illustration than is given in the 
paper, and will doubtless receive further attention in a later 
work. 

The paper is a valuable contribution to knowledge of the 
variations of Amblystoma; it does not add to the interesting 
problem of the cause of the non-transformation of the aquatic 
forms. We do not find ourselves in accord with the author’s 
proposition to consider this a dimorphic species having a terres- 
trial and an aquatic form, for this seems to put the aquatic form 
on a par with the terrestrial one. The aquatic form seems too 


138 THE AMERICAN NATURALIST [ Von. XLII 


occasional in occurrence and locality to justify this. We do not 
know but that all aquatic eases would have metamorphosed under 
suitable conditions, and the terrestrial form is indicated as 
being definitive by the anatomy of the circulatory and respira- 
tory apparatus. Also we do not share Powers’s objection to 
the name axolotl and siredon as a designation for the aquatic 
form; both have the sanction of general usage and do not apply 
to other animals, so that they are entirely clear. 

HoD O 


EXPERIMENTAL ZOOLOGY 


Some Experiments on the Development and Regeneration of the 
Eye and the Nasal Organ in Frog Embryos. —Dr. E. T. Bell has 
ċonducted a series of experiments on embryos of Rana esculenta 
and F. fusca, in which he found certain new facts in the develop- 
ment of the eye and nasal organ. Wolff had shown in 1894 that 
the crystalline lens of the salamander may be regenerated from 
the upper margin of the iris. Fischel also found later that 
the lens in the newt’s eye would regenerate from the iris, and 
by wounding the iris in several places after removal of the 
original lens that one or more lenses were formed. Spemann, 
Lewis and others show in amphibian embryos that there is no 
- localization of lens-forming material in any given area of the 
ectoderm, and that the formation of a crystalline lens depends 
directly upon the stimulation of the ectoderm, or outer embry- 
onic wall, through contact with the optic-cup. Lewis in a series 
of interesting experiments in which he tranferred the optic-cup 
from its original connection with the brain to a more caudal 
position showed that when it came in contact with the ecto- 
derm in this new region the optic-cup stimulated lens formation. 
In another instance the skin from the ventral surface of Rana 
sylvatica was placed over the optic-cup of R. palustris and gave 
origin to a lens. 

Bell has discovered several other possible sources of origin 
for the crystalline lens. He cut off the optic-vesicle of the 
embryo and turned it completely around so that the former 
outer side now turned toward the brain; under these conditions 
the pigment layer of the retina itself was induced to form a 
lens-like structure. When the brain was opened in the mid- 

1 Archiv fiir Entwicklungsmechanik der Organismen, XXIII, pp. 457-478, 
pl. 14 to 20. 


No. 494] NOTES AND LITERATURE 139 


dorsal line and the right optic-vesicle of another embryo of about 
the same size was put completely inside, the brain tissue, pro- 
vided it had not become too far differentiated, gave rise to a 
lens. In another case a lens was formed from the surface ecto- 
derm although the cavity of the optic-cup was turned away from 
the surface. An optic-vesicle which came in contact with the 
early nasal organ caused this structure to form a lens. Finally, 
the lens of one eye budded off another lens to supply an optic- 
vesicle which was placed adjacent to it. Bell’s experiments 
seem to show that all ectoderm cells before becoming specialized 
to any considerable extent have the power to differentiate into 
lens cells, though all of his experiments are not equally con- 
vineing. 

A lens failed to form from the endoderm when the gut was 
opened and the optic-vesicle turned down into its cavity. 

King with the frog and Dragendorf with the chick have shown 
that the optic-vesicle may regenerate when parts of its early 
structure are removed. If, however, the eye-forming region be 
completely destroyed these authors claim that no regeneration 
takes place. Bell, on the other hand, finds that when one lateral 
half of the brain is removed it will regenerate and at times an 
optie-vesicle forms on the regenerated side. He also removed, 
by means of fine scissors, the entire Anlage of the eye and 
found a new optic-vesicle to regenerate. The previous experi- 
menters used heated needles for destroying the eye and Bell 
believes that this method injures the adjacent tissue from which 
regeneration might take place. 

The formation of the pigment layer of the retina, Bell claims, 
is dependent upon the retina proper. There is also some evi- 
dence to show that the retina may cause undifferentiated epi- 
thelium to become pigmented when brought into relation with 
it at the proper time. : 

Bell finds that the optic, as well as the olfactory nerve, may be 
induced to follow a path that can in no sense be preformed. 

The olfactory lobes of the brain when brought into contact 
with ectoderm out of the nasal region are unable to stimulate the 
formation of nasal structures. The nasal anlage is readily re- 
generated if removed at certain stages and its early develop- 
ment is independent of the parts of the brain and buccal 
epithelium with which it normally connects. The nasal struc- 
ture is developed from a predetermined area of ectoderm and 
when this portion of ectoderm is transplanted to a position 


140 THE AMERICAN NATURALIST [ Vou. XLII 


above and behind the eye the nasal pit still forms and the olfac- 
tory fibers which develop in it grow into the lateral wall of the 
diencephalon above the eye, which is of course an unusual region 
for these nerve fibers to enter. 

C. R. STOCKARD. 


The Influence of Regeneration on Moulting in Crustacea.—A re- 
cent paper by Dr. Margarete Zuelzer* furnishes additional data 
regarding the influences of regeneration, or the replacement of 
lost parts, on the moulting process in crustacea. It is generally 
known that the members of this group have the power to grow 
new appendages, legs, antenne or swimmerets, after the former 
ones have been lost through accident or injury. In order to 
produce the new limb as well as to grow, or increase in body 
size, the crustacean must moult its hard chitinous shell. The 
processes of growth are closely associated with moulting and 
the more frequently the animal moults the faster will it in- 
crease in size. When one of these animals has lost a limb it is 
usually replaced by a small new one during the next moult fol- 
lowing the injury. 

Since the moulting period is so closely connected with the 
normal rate of growth several investigators have endeavored to 
ascertain what effect regeneration might have on the interval 
between these periods. Zeleny found that crayfish while regen- 
erating their limbs moult faster, or more frequently, than normal 
individuals, and, further, he holds that an animal regenerating 
several limbs moults more frequently "and regenerates the limbs 
faster than one replacing a single appendage. He concludes 
that during regeneration the moulting process is hastened. 
Emmel, on the other hand, has reached an opposite conclusion 
from the study of a large series of young lobsters. He finds 
normal individuals moulting more frequently than others which 
are regenerating new limbs. Lobsters that have lost several 
appendages moult slower than those that have lost fewer. 
Emmel, therefore, believes that regeneration retards the moulting 
process. He showed very clearly that an important factor, 
which Zeleny had failed to take into account, was the time at 
which regeneration was introduced into the moulting cycle. 
If the limbs were removed the day after moulting the moulting 
period remained almost normal, but when the limbs were re- 
moved four days after the moult the resulting regeneration 

1 Uber den Einfluss der Regeneration auf die Wachstumsgeschwindigkeit 
von Asellus aquaticus L. Arch für Entwick.-Mech., XXV, Dec., 1907. 


No. 494] NOTES AND LITERATURE 141 


lengthened the interval before the next moult by eighteen per- 
cent. The longer the time intervening between a moult and 
the removal of appendages the longer the following moult was 
postponed through the influence of the resulting regeneration, 
although the less likely was regeneration to ensue. 

Emmel’s experiments also seem to show that the retarding 
influence is due to the regeneration phenomenon and not to 
the injury sustained, since in all of his experiments those ani- 
mals that failed to regenerate new limbs did not have the 
moult following the operation postponed. 

In the young lobsters the regeneration process retarded their 
growth at times more than twenty-four per cent. 

Dr. Zuelzer, having the contradictory results of Zeleny and 
Emmel in mind, has undertaken a similar study on the little 
crustacean Asellus. Agreeing with Zeleny, she finds that in the 
majority of cases moulting occurs at shorter intervals if re- 
generation is taking place. The rapidity of moulting depends 
upon the time elapsing between the last moult and the time of 
operation, an important factor, as shown also by Emmel. 

f the animal is operated upon during the moulting stage 
or shortly after, the following moult is usually hastened by the 
regeneration phenomenon. When more time intervenes between 
the moult and the amputation of the limbs the tendency is to 
delay the first moult following the operation, but to hasten the 
second and third moults. Should the amputation of append- 
ages immediately precede a moult the moult occurs normally, 
‘but no regeneration is shown, the next moult is retarded and 
regeneration occurs; the third moult is accelerated and the 
regenerating limbs increased in size. Occasionally when the 
operation preceded the moult by a considerable interval no 
regeneration occurred, although the moult may have been 
hastened. 

When the two antenne are cut at different levels so as to 
leave stumps of unequal lengths, the longer one regenerates at 
a slower rate than the shorter, so that the original equality in 
length is again established. Zuelzer considers this a case of 
‘“eompensatory regulation,” that is, the short stump influenced 
the longer one to regenerate slower than it would otherwise have 
done in order to reestablish.their equality in length. This dif- 
ference in growth rates may be equally well explained as due 
to the levels at which the cuts were made on the two antenne, 
as Morgan has shown for the fish’s appendage that the nearer 


142 THE AMERICAN NATURALIST [Vou. XLII 


the edge or tip of a fin the cut is made the slower will be the 
rate of growth of the new tissue. 

Repeated amputation, or removal of regenerating buds, con- 
tinues to accelerate the moulting process. Zeleny has shown 
in Cassiopea, a jelly-fish, that repeated operation also hastens 
the rate of regeneration. New tissue grows faster from a cut 
surface that has previously regenerated tissue than from a newly 
cut surface that has not before regenerated. 

Zuelzer finds, like Emmel, that the moulting time is unaffected, 
or she believes at times hastened, in those cases where regenera- 
tion fails to follow the amputation of appendages. The reason 
for this she thinks may be that the animal with fewer append- 
ages has a smaller body mass and, therefore, more food to 
use in normal growth, particularly when none of this food is 
used to form regenerating tissue. Thus Emmel’s lobsters which 
failed to regenerate moulted more rapidly than regenerating 
ones. When one considers, however, the apparent unimportance 
of food-supply on regeneration phenomena as shown by Morgan 
he becomes disinclined to accept Zuelzer’s explanation. 

In a general way Zuelzer agrees with Zeleny in that regen- 
eration hastens the moulting process. It is interesting to note 
that both of these workers have used adult crustacea while 
Emmel’s experiments were made upon larval or young lobsters 
and gave opposite results. A possible reconciliation of the re- 
sults may be as follows: The young lobsters, like most young 
animals, are growing at a maximum rate; all available energy 
is being used in growth. When such animals are injured they 
receive a ‘‘set-back’’ since some of their energy must now be 
diverted in order to repair the injury. Emmel showed that 
the process of regeneration retarded the rate of growth of these 
lobsters sometimes more than twenty-four per cent., but when 
the injury was not repaired growth or moulting was not re- 
tarded. Adult animals, on the other hand, are not living up 
to their maximum possibilities; they are in an apparent state of 
reserve until the removal of an appendage or other injury 
excites them to new activities and regenerative growth begins. 
During regeneration the animal may be said to be in a con- 
dition of newly stimulated growth and all growth activities are 
probably influenced. One may predict that if similar regen- 
eration experiments be tried on the adult lobster the results 
will agree with those obtained on adult crayfish and Asellus. 

C. R. Srockarp. 


No. 494] NOTES AND LITERATURE 143 


Experiments in Transplanting Limbs and their Bearing upon the 
Problem of Development of Nerves.—Students of nerve regenera- 
tion are divided into two camps according as they view the in- 
fluence of the central or ganglion cell on the regeneration of 
peripheral nerve fibers. On the one hand it is assumed that 
no regeneration can take place in peripheral nerves that are 
isolated from their ganglion cell. On the other hand it is 
assumed that regeneration can take place in the complete ab- 
sence of central influence. This is often spoken of as ‘‘auto- 
regeneration.” 

The latter view finds its most recent exponent in Dr. Braus, 
of Heidelberg, who was led to it by the results obtained in 
transplantation experiments. He found that either the trans- 
planted limb contained no nerves at all, or that functional nerves, 
typical in their distribution, were developed from any region of 
the body, whence they must have arisen in situ and secondarily 
come to unite with the ganglion cell. 

A few details may be mentioned because of their extreme 
interest. Young tadpoles were used in which nerves had not 
penetrated to the limb buds. When such buds were transplanted 
to other regions of the body of a second tadpole, a limb developed 
in this bizarre position, quite normal in the structure of all of 
its parts, ineluding its nerves. Posterior limb-buds were suc- 
cessfully grafted on the head, and posterior legs developed. As 
no nerves had been present in the buds at the time of transplan- 
tation, and as it seemed inconceivable to Braus that facial nerves, 
for example, could grow into the parasitic leg and show in the 
distribution of its parts an arrangement typical of normal limbs, 
he concluded that nerves must have developed in situ. 

In‘a second series, the region which later gives rise to the nerve 
cells and fibers of the body was removed. Limb-buds from these 
‘‘aneurogenic’’ individuals were grafted upon normal tadpoles 
and once again development of the limbs proceeded, but nerves 
were absent. If they grew centrifugally one should expect to 
find these limbs innervated by the outgrowing nerves from that 
particular region. 

Professor R. G. Harrison, of Yale University, has rendered 
invaluable service in repeating and extending Braus’s experi- 
ments, in a paper entitled ‘‘ Experiments in Transplanting 
Limbs and their Bearing upon the Problem of Development of 
Nerves,’’ in the Journal of Experimental Zoology, vol. 4, 1907. 


144 THE AMERICAN NATURALIST [ Von. XLIÄ 


In the first place, a careful examination of serial sections 
showed that nerves grow close to the region from which the 
transplanted buds were removed. The finer twigs of host and 
bud were thus brought into close union. It has been well es- 
tablished by a number of investigators that fhe union of the 
peripheral fiber of one nerve with the central fiber of another 
permits the functioning or regeneration of the former. This 
fact indeed is frequently taken advantage of in modern surgery. 
Similarly accurate examination of serial sections showed con- 
clusively that, in the transplanted limbs taken from ‘‘aneuro- 
genic” individuals, nerves were present, and that these were 
quite normal down to their minute details. There is thus pre- 
sented the anomaly of a facial nerve, for example, growing along 
entirely new paths, whose direction is determined by the struc- 
tures in the limb. Such distribution is thus not a function of the 
nerve, but of the organization of the limb which it innervates. 

These more accurate methods revealed the further fact that 
accessory limbs, which are sometimes produced at the point of 
transplantation, also contain nerves often in a high degree of 
perfection. Braus had denied, on insufficient evidence, the pres- 
ence of these nerves and had urged their absence as an argument 
opposed to their centrifugal growth. 

By the aid of a very ingenious experiment, Harrison pushed 
the inquiry one step farther. ‘‘Aneurogenic’’ individuals, 
Braus and Harrison both found, were short lived. To over- 
come this difficulty, Harrison grafted an ‘‘aneurogenic’’ tadpole 
to the side of a normal or ‘‘nurse,’’ and to the former he 
transplanted a limb-bud from a normal individual. A develop- 
ing nerve was thus transplanted to a nerveless region. Though 
the results were not altogether satisfactory, the evidence pointed 
to the conclusion that ‘‘there is no progressive development of 
the nerve. On the contrary, there are rapid regressive changes, 
which in the majority of cases result in the entire disappearance 
of the nerves within a few days after they are cut off from their 
centers.”’ 

On the whole, though the paper is exceedingly accurate—a 
characteristic of Harrison’s work—so far as it goes, it does not 
settle the question, especially in the light of Bethe’s recent con- 
tribution. Perhaps, after all there is an element of truth on both 
sides, and just how much value to put to each is the problem to 
be decided. 

A. J. G. 
(No. 493 was issued March 21. 1908.) 


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WALKER PRIZES IN NATURAL HISTORY 


By the provisions of the will of the late Dr. William Johnson Walker two 
prizes are annually offered by the Boston SOCIETY OF NATURAL History for the 
best memoirs written in the English language, on subjects proposed by a Committee 
appointed by the Council. 

For the best memoir presented a prize of sixty dollars may be awarded ; if, how- 
ever, the memoir be one of mark merit, the amount may be increased to one 
hundred dollars, at the discretion of the Committee. 

For the next best memoir a prize not exceeding fifty dollars may be awarded. 

Prizes will not be awarded unless the memoirs presented are of adequate merit. 

The competition for these prizes is not restricted, but is open to all. 

Attention is especially called to the following points: 

In all cases the memoirs are to be based on a considerable body of original 
and unpublished work, accompanied by a general review of the literature of the 
subject. 

Anything in the memoir which shall furnish proof of the identity of the 
author shall be considered as debarring the essay from competition. 

3. Preference will be given to memoirs showing intrinsic evidence of being 
based upon researches made directly in competition for the prizes 

4, ch memoir must be accompanied by a sealed envelope enclosing the 
author’s name and superscribed with a motto corresponding to one borne by the 
manuscript, and must be in the hands of the Secretary on or before April ist of the 
year for which the prize is offered. 

5. The Society assumes no responsibility for publication of manuscript 
submitted. 

SUBJECTS FOR 1908: 

1. An experimental study of inheritance in animals or plants. 2. A com- 
parative study of the effects of close-breeding and cross-breeding in animals or plants. 
3, A study of animal reactions in relation to habit formation. 4. A physiological 
study of one (or several) species of plants with respect to leaf variation. 5. Fertiliza- 
ti i related pl in a phenog plant. 6. What proportion of a plant’s 
seasonal growth is represented in the winter bud? 7. A physiographic study of the 
forms and processes discoverable along a varied shore line. 8. A problem in 
structural geology. 9. A study of one or more geological horizons with a view to 
determining the different conditions obtaining at one time over a large area, as 

ed by sediments and fossils. 
SUBJECTS FOR 1909: 

1. A geographie study of a district of varied features, presented as involving 
the natural relations of inorganic and organic elements. 2. A petrographic study 
of a district of erystalline rocks. 3. A paragenetic study of a mineral locality. 4. 
The conditions controlling sexual reproduction in plants. 5. Studies in the life 
history of a thallophyte, with special reference to sporogenesis. 6. Contribution to 
our knowledge of response in plants. 7. The factors governing orientation in animal 

nses. 8. The relation between primary and secondary sex characters in 
animals. 9. The activities of the animal body in relation to internal secretions. 
Boston Society of Natural History, 

Boston, Mass., U. S. A. 


GLOVER M. ALLEN, Secretary 


¥ 
VOL. XLII, NO. 495 MARCH 


THE 


AMERICAN 
NATURALIS 


A MONTHLY JOURNAL 
DEVOTED TO THE NATURAL SCIENCES 
IN THEIR WIDEST SENSE 


CONTENTS 


Lamarck Manuscripts at Harvard University. Professor BASHFORD DEAN 
Symbiosis in Fern Prothallia. Professor DOUGLAS HOUGHTON CAMPBELL 
The ebes of the Tertiary Mammals and the Importance of Their Mi- 

gratio: Professor CHARLES DEPERET 
orsi Regarding the Constancy o of Mutants and Questions Regarding 


What is 4 “Species s? Professor 8. W. WILLISTON 
Shorter Articles and Correaponiiencs : The Inheritance of the Manner of 
Clasping the Hands, Dr. FRANK E. Lutz 
Notes and rape Tehthology—Tehthysogica Notes, prii iva 
STARR JOR Echinoderm e Stalked Crinoids of the Siboga 
T. 


Expedition, "kes HOBART Peis / decane Patho 
Diseases, Professor HENRY B. WARD. Animal Behavior—Recent Work 
on the Behavior of ang Animals, Professor HERBERT S. JENNINGS. 


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, 1908 


THE AMERICAN NATURALIST 


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THE 


AMERICAN NATURALIST 


Vout. XLII March, 1908 No. 495 


THE LAMARCK MANUSCRIPT IN HARVARD 


PROFESSOR BASHFORD DEAN 
COLUMBIA UNIVERSITY 


Lamarck manuscripts are exceedingly rare. For until 
the last score years Lamarck was ranked as a discredited 
author, and his writings were thrown aside. Even the 
autograph collector, to whose nets almost everything is a 
fish, has hardly taken the pains to preserve his bare 
signature. The Harvard manuscript, accordingly, is an 
important document, especially in these days of La- 
marckian revival. It is holographic, antedating, there- 
fore, 1818-20, the years when Lamarck’s eyesight was 
lost. It forms together a series of essays and drafts of 
later work, all in all about ninety leaves, of which fifty 
have writing on both sides. They are brought together 
in a volume with marbled sides and morocco back with 
the legend, ‘‘Manuscrits de Lamarck,’’ the binding 
dating 1830-40. As a frontispiece there is inserted the 
Langlumé lithograph of Alexis Noél’s portrait of La- 
marck (1823). Following this is a table of contents, 
probably in the hand of the early owner of the manu- 
seript. It reads: 


Manuscrits | de | J. B. P. A. de Lamarck | Membre de Pinstitut de 
france, Professeur-admi- | nistrateur du Museum d’histoire naturelle, ect. 
contenant}. 


1° Systéme de Gall.. .ss.-- -cerror ertererears 
2° Idée et Imagination .......-s...seseeresess 
3° Appereu analytique de connaissances humaines. 11 

145 


20 fuillets 
19 “ 


“ 


146 THE AMERICAN NATURALIST (Von XLII 


& Questions Zostogianee.. is oak ec eee cin ges 
9- Histoire natureho we doc i ce oes re es es 3 
6° Planches préparées pour les figures des genres 
qui feront partie de la 2° édition des animaux 
pano vertebre. sso Si Fs ca cae 19 fuillets 
OUR Occ ia oa bik oe bis co ews ues eee: 81 fuillets 


From this it will be noted that the papers were collected 
before 1835, the year of the appearance of the second edi- 


Jean Baptiste, Pierre-Antoine Monet de Lamarck. 


tion of the ‘‘Animaux sans Vertébres,’’ for it is stated 
that the drawings will form part of the second edition, 
not that they did form part of it. 

This manuscript was presented to Harvard University 
in 1896 by Professor Alexander Agassiz, who appears to 
have discovered it in Paris. Its earlier provenance is 
unknown. My attention was called to it by my friend, 


No. 495] LAMARCK MANUSCRIPT IN HARVARD 147 


qucslioms goo logiques 
Jout A elution yt de Vemceve imporlance 


\*7* question : lu animaux tly vegeta lant Oy se Hoang 
Cy 2 on Oe af de j Confondent=il a iia polt ene Oy hvi 
qp elly forment A 0m erish. Fa quelqu Cavachre exclusif D a 
Teaches q dyfague sack les premiers Jes vecondy 7 
2. quslion ; eul-on mellve en Whence ; ‘eas be cilslion de fail decisifs 
i. f 
que Tous ly animaux Conny joui fent ou enliment . ou r af 
‘ -f ; / pews se ‘ y ’ 
: ny a 2 une pave dent eax bay laud Joues Je ceke Pacalte ? 
2., question > peil-on A dsc cas ay Deg pi’ paveillement decilifs gie 
é i : o ' 
fous lu animata connus poflent la faculle’ asec des ides tde 
former cte ER EEE av remed laksu feita i 9o- 
ay 1 Se, Cae el: 
onlarye ment it pevmet de vaviev ls acliong jp ou wiiiny a 
qu'une pavle deg animau qui jouifent ok faculta ? 
A. question : 7 a-tif quelque paculle animale que ne lif pas un 
Phenomene douganisalion at qu it independante Ds toad uyg- 


{ 


ee fe gpelcongue ; ou toule frcalle qai nyh as m- 
une a Tou ly animaux ne Jepend. Ya ay Jun deia br 
Couliey Soeganes qué y Be. sr r A 3 
5 : quslion : É; ls animaux Counus polet ik Att dy 
vy s femss paves bwy dovrganeg e compesent Lovaaniyalion fry 
Compliquee Oe. animaux bs ly par fails i ne gues cy Uys tines 
Vovganes ied” affentiels ala gic dans hs ye sete Animaux 7 hg 
7 of edat, la gie dams d aulres iy annae PE teke pas or tev 


A Page of the Harvard Manuscript (p. 113). 


148 THE AMERICAN NATURALIST [ Vou, XLII 


Dr. C. R. Eastman, who was generously instrumental in 
placing it in my hands. To him, therefore, and to Pro- 
fessor Samuel Henshaw, curator of the Museum of Com- 
parative Zoology, my thanks are due for the privilege of 
examining it. 

In further detail, and in the matter of its published or 
unpublished parts: 

The Système de Gall is largely medical: it deals with 
the brain, its anatomy, comparative anatomy, physiology, 
pathology —the last in some detail as in idiocy, cretanism, 
suicidal mania, hereditary insanity. I cannot find that 
it has been published. 

The second essay, Idée et Imagination, has certainly 
been published. It bears the note in Lamarck’s hand, 
** Articles du diction,’’ and is signed by compositors. Dr. 
Eastman suggests that it occurs in Nouv. Dict. Hist. Nat. 
of Detérville, 1818, a work I have not been able to con- 
sult. The writing indicates an earlier date than the 
remaining leaves. 

The third portion, Appercu analytique des connais- 
sances humaines, avec des divisions et des reflexions ten- 
dant à montrer leur degré de Certitude, leurs Sources, 
leurs Branches principales, is probably the outline of-his 
extended work (362 pp.) on the same subject published 
in 1820: it is entirely in his own hand and probably dates 
not later than 1818 (the year in which his eyes failed 

im). 

Of the fourth manuscript, Questions Zoologiques, the 
first section is substantially as follows: 

“ Zoological questions whose solution is of first importance. 

“ First QuestionAnimals and plants being living bodies (corps), 
do these two kinds of organisms become confused (se confondent) at 
a common point of the series which they form; or does there exist 
some exclusive and trenchant elfaracter, which distinguishes sharply the 
first from the second? 

“ Second Question.—Can one show by the citation of decisive facts, 
that all animals known are endowed with sensation;* or that there are 
only certain of them which are endowed with this faculty? 

1 Lamarck uses the word ‘‘sentiment.’’ From several contexts, however, 
one concludes that more than ‘‘sensation’’ is intended, and that ‘‘con- 


No. 495] LAMARCK MANUSCRIPT IN HARVARD 149 


“Third Question.—Can one prove by facts equally decisive that all 
animals known possess the faculty of having ideas and of determining 
them by premeditation,—a premeditation which is formed voluntarily 
and which permits the actions to be varied; or are there only certain 
animals which enjoy this faculty? 

“Fourth Question—Is there some faculty in animals which is not 
a phenomenon of organization and which is independent of all sys- 
tems of organs whatever; or does not every faculty which is not common 
to all animals depend for its origin upon a particular system of organs. 

“Fifth Question.—Do all animals known possess the totality of the 
particular systems of organs which make up the very complicated 
organization of the most perfect animals; or, however essential are 
these systems of organs to the life in the animals which possess them, 
can not life in other animals exist without them? 

“ Sixth Question.—Is there known a single organ which is essen- 
tial to animal life (in general) whatever be its function in the par- 
ticular organism of which it forms a part; or must we not assume that 
life, whether of plant or of animal, needs no particular organ whatever, 
to enable it to exist in certain organisms. 

“ Seventh Question.—Cannot sensation (sentiment) and irritability 
be regarded as one and the same organic phenomenon and can it 
not be proved by facts that every portion of an animal which is en- 
dowed with irritability is also endowed with sensation; or is not irrita- 
bility with which all animals are endowed, whether in all their parts 
or in certain of them only, an independent phenomenon and distinct 
from the sensation enjoyed by many animals 

“ Eighth Question—Can it be established clearly that the facts of 
movement in the case of so-called sensitive plants demonstrate in these 
plants either sensation or irritability; or that these facts have no re- 
lationship whatever with those which demonstrate in animals on the 
one hand sensation and on the other irritability? 

“ Ninth Question—The nerves alone are the organs of sensation since 


sciousness’’ might often be the better rendering. Thus in the eighth ques- 
tion referring to sensitive plants he distinguishes sharply ‘‘sentiment’’ from 
‘‘irritabilité.’? The latter gives the idea of unconscious reflex to stimulus, 
and the former then becomes antithetic, i. e., conscious. literal text 
in this question reads ‘‘peut on établir d’une maniére evidente, que les 
faits de mouvement relative aux plantes dittes sensitives, constatent dans 
ces plantes soit le sentiment, soit l’irritabilité ; ou que ces faits n’ont aucun 
rapport avee ceux qui attestent les uns le sentiment, les autres Virritabilité 
des animaux?’’ Again, i questions second and third, it is clear 
that ‘‘sentiment’’ in the second question is distinguished from igher 
form of consciousness, sia is equivalent to reason (or ES In 
general we assume that the phrase ‘‘avoir le sentiment’’ implies con- 


sciousness. 


150 _ THE AMERICAN NATURALIST [ Vou. XLII 


the faculty of sensation is lost in a part (of an animal) in which the 
nerves supplying it have been destroyed; now the question is whether 
every nerve produces a sensation when it is affected, and whether the 
nerves which bring the muscles in action as well as those which furnish 
the forces of action to the organs produce sensation, like the rest; or 
whether there are not particular and special nerves for the production 
of sensation, while the others function some for muscular excitation, 
the others only for putting different organs in a condition to execute 
their functions? 

“Tenth Question.—Is there some constant and peculiar sign which 
will make us understand that a being differing from ourselves ex- 


rol act. la. { 
meade pel, t us ae ie 
l a O 
o o 
Se. Ca on O i © o: 
s ee A 
Pa Tiik e o 


3 . 2 
m Sh bo oe 
A .. Pean ay Q p K O 


Lamarck’s Pen-drawings of Microorganisms (MS. p. 145). 


periences a sensation when it is stimulated (affecté), and can one 
always accept as a test the similar movement which it then executes; 
or, however in general an animal gives no other sign of a sensation 
produced than by the movements of its parts, can not these movements 
often deceive us and be due only to the irritability excited in the parts 
of the animal? 

(I know no certain sign of a sensation produced save a cry evoked 
by pain: but all animals are not able to give such a sign and those 
which have the power do not always use it.) 


No. 495] LAMARCK MANUSCRIPT IN HARVARD 151 


“ SUPPLEMENTAL QUESTION: 

“Eleventh Question —If each particular system of organs gives rise 
to a particular faculty, can this faculty be found again in an animal 
in which the system of organs which produces it no longer exists; or 
can not this same faculty be regarded as destroyed when the system 
of organs which has given rise to it ceased to exist?” 


These questions date from the period 1810-18, with 
the probability that they belong nearer the later than the 
earlier date, for in his ‘‘ Philosophie Zoologique’? (1809) 


fangs J Koleda pl. 6 
2 
NY$ WES ¢ "> 
Bivpaiv.:. pls. ie eS plete. 
tò S on (Sue a a7 


Kei vene.pl. 17. pee ag 


© Qe pier! foro py, 
S 2 ssa l ae 
Or” = a 


Lamarck’s Pen-drawings of es L p. 147). 


his views were by no means as advanced. He then spoke 
of the essential differences which distinguish plants and 
animals, and did not query their common origin, and did 
not seek a trenchant character which would serve to dis- 
tinguish them. Moreover, he did not then query the 
possible kinship of sensation and irritability in sensitive 
plants and in animals, for at that time he had seen no 
reason to deny the elastic-fluid explanation for the sensi- 
tive movements of plants. Altogether these questions 
are of considerable interest in the study of the develop- 


152 THE AMERICAN NATURALIST [ Vou. XLII 


ment of Lamarck’s views. They had, however, hardly 
reached the level of his Introduction to the second edition 
of his ‘‘Animaux sans Vertébres’’ (1835). But we can 
regard them as sure steps in that direction, for similar 
ideas are here and there found in the Introduction. 
Indeed the second part of these Questions Zoologiques, 
MS. pp. 117-130, undoubtedly served as a first draft of 
this. Thus the present p. 117 is equivalent to p. 17 of the 
Introduction, and one can identify nearly all of the 
remaining leaves. 

The fifth portion is headed ‘‘ Histoire naturelle,’’ and 
deals with its scope. It appears to have been a draft of 
a portion of the second edition of the ‘‘ Animaux sans Ver- 
tébres,’’ for it is captioned ‘‘Chap. 4. Connaissance des 
Corps organisés vivans que s’observent a la surface de 
notre globe et dans les eaux liquides,’’ but these lines 
have been crossed out. The same ideas occur in the pub- 
lished work but in different form, so it is perhaps un- 
necessary to append here the entire section. The last 
page will give an idea of its tenor: 


A Color-drawing of a Holothurian, 


No. 495] LAMARCK MANUSCRIPT IN HARVARD 153 


‘‘ Living bodies and inorganic bodies are the materials 
of natural history. They compose together the mass of 
the terrestrial globe, but they occur in very different 
proportions, for the first form a portion exceedingly 
small, while the second constitute almost the totality. 

‘*Yet the bodies which are possessed of life are innu- 
merable in the diversity of their species, and those, on the 
other hand, which lack it, exhibit in proportion only a 
small number. Indeed, we know hardly more than six 
or seven hundred species of minerals, while the number of 
species of living bodies can not be estimated as less than 
100,000.? 

‘‘ These considerations are not lacking in interest, pro- 
voking our reflections, and each one of them presents us 
a fact, an item of knowledge with which we have to reckon. 
In a word these singular bodies which possess life, which 
are so diversified, are yet the constituents of but a very 
small portion of the globe which man inhabits.’’ 

The final pages of the manuscript contain the following 
drawings: 

Plate I, monads, volvoce, enchelide, protée, vibrion, 
goue, cyclida. 

Plate II, paraméce, kolpode, Bursaire, tricode [leuco- 
phre], Kérone, cercaire, fureocerque. 

Plate III, Ratule, tricocerque, vaginicole, folliculina, 
Brachion, furculaire. 

Plate IV, urcéolaire, vorticelle, tubiculaire. 

The remaining pages include the ‘‘animal of lepas 
balanus,’’ with parts named, ‘‘millipora gelatinosa,’’ a 
color sketch, a number of jelly fishes, including ‘‘dianée 
triedre,’’ ‘‘orythie verte,” ‘‘orthie hexaneme,’’ ‘‘dianée 
proboscidale,’’ ‘‘dianée dineme’’; a number of nudi- 
branchs, pteropods, and a beautifully colored drawing of 
_ a living holothurian. 

2 A generous estimate for that period—a number now several times ex- 
ceeded within the insecta. 


SYMBIOSIS IN FERN PROTHALLIA 


PROFESSOR DOUGLAS HOUGHTON CAMPBELL 


STANFORD UNIVERSITY 


THE symbiotic associations so frequently met with in 
plants present one of the most interesting phenomena 
with which the biologist has to deal. While these asso- 
ciations are often not easily distinguishable from true 
parasitism, in many instances there is a genuine symbi- 
otic relation and, although there may be a certain degree 
of parasitism, there is no question that these associations 
are for the most part beneficial to both of the forms con- 
cerned. Indeed, the very existence of one or both of the 
symbionts may depend upon it. 

In most cases of symbiosis, one of the symbionts is a 
fungus, but this is not always so. Certain of the Schizo- 
phyceæ or blue green algæ are very commonly associated 
with higher plants in what appears to be a symbiotic re- 
lation, although the nature of the association in this case 
is still very obscure. The Anthocerotacee and several 
of the liverworts, like Blasia, always have within their 
tissues colonies of a Nostoc, and the little water fern 
Azolla invariably harbors in each leaf a colony of the 
Nostoc-like Anabena Azolle. Nostoc has been found to 
occur in the roots of Cycas revoluta and Gunnera among 
the seed plants, and the Schizophycee also frequently 
constitute the ‘‘gonidia’’ of many lichens. The associa- 
tion of the nitrogen-fixing bacteria with the root nodules 
of the Leguminosz is also a well-known case of symbiosis. 
Of the true alge there are a number of species recorded, 
e. g., Chlorochytrium Lemne, which live within the tis- 
sues of higher plants, but it is doubtful whether the host 
is in any way affected by the presence of the alga, which 

154 


No. 495] SYMBIOSIS IN FERN PROTHALLIA 155 


presumably secures lodging, but not board, from its 
host. 

The symbiotic association of fungi with green plants 
was first demonstrated in the lichens, but it is now known 
that many of the higher plants are regularly associated 
with fungi in what is undoubtedly a symbiotic relation. 
The best known cases of these are the mycorhizal fungi 
connected with the roots of many trees, especially the 
Cupulifere, and those which occur in the tissues of sapro- 
phytes growing in humus. These humus saprophytes 
are especially numerous among the Orchidacex, e. g., 
Neottia, Corallorhiza, Cephalanthera, ete., and in certain 
forms of the Ericales. The well-known Indian pipe, 
Monotropa uniflora, and the snow plant of the Sierra 
Nevada, Sarcodes sanguinea, are well known examples 
of these saprophytic Ericales. Many Orchidacew and 
Ericacee which possess chlorophyll are also to a greater 
or less extent saprophytic and show a well-developed 
mycorhiza. In the case of chlorophylless plants, there 
can be little doubt that the fungus enables them in some 
way to utilize carbonaceous compounds from humus. In 
the case of plants such as the trees referred to, where 
there is ample chlorophyll tissue, it is more likely that 
the rôle of the mycorhiza is rather to supply nitrogen 
than carbon, and it is highly probable that in the case 
of chlorophylless saprophytes as well, the fungus pro- 
vides nitrogen. This has recently been demonstrated 
for the mycorhiza found in the roots of various Hricacee, 
e. g., species of Erica, Vaccinium, Calluna and Oxycoccus’ 
In all of these it was shown that the fungus concerned, 
which seemed to be a species of Phoma, was able to as- 
similate free nitrogen in much the same way as is done 
by such nitrogen bacteria as Azotobacter. 

A very complete study of the endophytic fungi of roots 
has been made by Janse.? He examined a very large 

1 Dr. Charlotte Ternetz. Über die Assimilation des atmosphärischen 
Stickstoffes durch Pilze. Pringsheim’s Jahrbücher, XLIV, July, 1907. 

2Les Endophytes Radicaux de quelques Plantes Javanaises. Ann. du 
Jardin Botanique de Buitenzorg, XIV, 54-201, 1895. 


156 THE AMERICAN NATURALIST [ Vou. XLII 


number of plants, mostly phanerogams, but also a num- 
ber of liverworts and pteridophytes. His researches 
showed the presence of an endophytic mycorhiza in a 
surprisingly large number of plants belonging to the most 
diverse families, from Zoopsis, one of the Hepatice, to 
Vernonia, a genus of Composite. 

The study of the mycorhizal fungi of the seed plants 
has called attention to the presence of similar fungi in 
the pteridophytes. The occurrence of a mycorhiza in the 
roots of the Ophioglossacew was first shown by Russow.’ 
In 1884 Treub described a similar fungus from the game- 
tophyte of Lycopodium. In his very important paper 
on the prothallia of Lycopodium‘ he pointed out the 
universal occurrence of this fungus in L. cernuum, and 
in later papers he showed that this also occurred in L. 
phlegmaria, as-well as in some other species, but it was 
apparently absent from the green prothallium of L. sala- 
kense. In 1895 I called attention to the presence of a 
similar endophytic fungus in the subterranean prothal- 
lium of Botrychium virginianum. 

The past decade has been notable for the numerous 
important investigations upon the gametophytes of the 
Ophioglossacee and the Lycopodiacew and our knowl- 
edge of these is now quite complete, thanks to the labors 
of Bruchmann, Lang and Jeffrey. It is clear that in all 
prothallia of the subterranean, and hence purely sapro- 
phytic type, an endophytic fungus is invariably present. 
It has also been shown that a similar form occurs in the 
green prothallium of some species, at least, of Lycopo- 
dium ; but so far as I am aware its occurrence in the green 
prothallium of ferns has not hitherto been recorded. 

Some time ago, having occasion to look over slides of 
the prothallium and embryo of Osmunda cinnamomea, it 
was noted that many of the prothallia contained an endo- 
phytie fungus very similar to that found in Botrychium 

* Vergleichende Untersuchungen der Leitbiindelkryptogamen. Mem. de 
1’Akad. Imp. des Se. de Petersbourg, 1872, XIX, 107-118. 

“Etudes sur les Lycopodiacées. Ann. du Jardin Botanique de Buiten- 
zorg, IV, 1884. 


No. 495] SYMBIOSIS IN FERN PROTHALLIA 157 


and Ophioglossum. This suggested the possibility of its 
occurrence in other green prothallia, and the forms which 
seemed to promise best were the Marattiacew, which in 
many ways seem to be the nearest relatives of the Ophio- 
glossacex, in whose subterranean prothallia the endophyte 
regularly occurs. I therefore made an effort to obtain 
prothallia of the Marattiaceew while collecting in Ceylon 
and Java, and procured prothallia of Angiopteris evecta 
Hoffm, Kaulfussia esculifolia Bl., and Marattia sambu- 
cina Bl. The two former were carefully studied, and as 
was expected, the endophyte was found in nearly every 
case. The prothallia of Marattia sambucina were not 
examined, but the examination of a series of sections of 
M. Douglasii Baker, made some years ago, showed that 
in this species the endophyte was also present and pre- 
sumably it occurs also in other species of Marattia. 
The other family of ferns in which it was thought the 
endophyte might occur was the Gleicheniacer, a small 
family, mostly tropical and of wide distribution. The 
Gleicheniacer are considered to be related to the Os- 
mundaceæ and it was thought that they also might show 
the presence of the endophyte. The prothallia have rarely 
been collected, but are not difficult to find if one looks 
for them carefully. Material of four species was secured, 
one being collected near Cape Town, the others in Ceylon 
and Java. In all cases the endophytic fungus was found 
in the older prothallia. 
` These investigations show conclusively that an endo- 
phytic fungus is normally present in the green prothallia 
of several Marattiacew, Osmundacee and Gleicheniacee, 
and it is highly probable that further research will show 
similar fungal endophytes occurring in the prothallia of 
many other ferns. 


THE STRUCTURE OF THE ENDOPHYTE 


Since the discovery of the endophytic fungus in the 
gametophyte of Botrychium, it has been found constantly 


158 THE AMERICAN NATURALIST [ Vou. XLII 


in all the investigated species of Ophioglossacex, and it 
is safe to assume that it is invariably present and is 
essential to the growth of the gametophyte. 

The writer has recently had occasion to study the be- 
havior of this endophyte in the gametophyte of several 
species of Ophioglossum and has described and figured 
this somewhat at length.’ The fungus consists of non- 
septate, large, branched hyphæ, which are strictly intra- 
cellular, passing from cell to cell through the cell walls, 
and they may often be traced for long distances. In all 
of the forms that have been investigated the fungus is 
confined to the older parts of the gametophyte, and never 
invades the meristematic tissues nor the tissues in the 
neighborhood of the young reproductive organs. There 
is in the cylindrical branches of the gametophyte of Ophi- 
oglossum a more or less definite infected zone inside the 
superficial tissues, while the central region remains al- 
most entirely free from the endophyte. Sometimes frag- 
ments of mycelium are found upon the outside of the 
gametophyte, and these may occasionally be found to 
penetrate into the rhizoids and thus gain entrance to the 
inner tissues. The infection, however, probably in all 
eases takes place first while the gametophyte is still 
composed of very few cells. This was positively demon- 
strated in the germinating spores of O. pendulum, where 
only those young prothallia which succeeded in establish- 
ing a connection with the fungus developed beyond a 
three or four-celled stage. Otherwise they died after 
the nutrient matter in the spore was exhausted. Second- 
ary infections, however, doubtless take place frequently. 
The form of the fungus growing outside of the prothal- 
lium is quite different from that within its tissues. The 
hyphæ in the former case are more slender and some- 
times septa may be formed, while these seem to be quite 
absent from the endophytic hyphe. 

In material fixed with chromic acid, the structure of 


5 Campbell. seni on the Ophioglossaceew. Ann. du Jardin Botanique 
de Buitenzorg, XXVI, re 


No. 495] SYMBIOSIS IN FERN PROTHALLIA 159 


the hyphe is well shown. The walls, which in the ordi- 
nary hyphe are moderately thick, stain well with gentian 
violet, while in the finer granular cytoplasm there are 
more or less numerous small bodies which stain strongly 
with safranin and are with little question nuclei. Some 
of the cells of the host contain unmodified hyphæ, which 
may be so numerous as to fill the cell cavity with a dense 
coil of filaments. In other cells the hyphe form masses 
of irregular swollen vesicles with much more delicate 
walls than the ordi- 
nary hyphe, and 
sometimes quite fill- 
ing the cell. Besides 
the irregular vesicu- 
lar swellings of the 
hyphe described 
above, there may 
occur large oval or 
round structures 
(Fig. 1) which re- 
semble the young 


oogonia of Pythium Fic. 1. A, Cell from the gametophyte of 
Ophioglossum pendulum, showing the mycelium 

or 

Albugo $ These of the endophyte, and a young conidium (?) ; st, 

may have a diameter masses of disintegrating starch granules; B, 


of nearly 50 By but large conidium (?) of the same; C, fully de- 
abe “usually Gallen nt es ee 
The nuclei in these 
bodies are more numerous than in the vegetative hyphe, 
and finally may be very conspicuous (Fig. 1, C). 
This multiplication of the nuclei resembles the pre- 
liminaries of zoospore formation in the sporangia of 
Saprolegnia or Pythium, and occasionally there were 
seen free in the host cells small bodies that looked as if 
they might have been discharged from these large oogo- 
nium-like bodies. The latter are probably identical’ with 
* Jeffrey. The Gametophyte of Botrychium Virginianum. Proc. Canad. 
Institute, V, 1898. 


160 THE AMERICAN NATURALIST [ Vou. XLII 


the ‘‘conidia’’ described by Jeffrey in Botrychium, but 
do not show the thick walls of these conidia. Like these 
conidia of Botrychium they are not, usually at least, 
separated from the filament by a septum. The young 
cells of the gametophyte contain starch in the form of 
rather small and very distinct granules. As the endo- 
phyte invades these cells, the starch granules soon show 
evidences of disintegration, swelling up and losing their 
sharp contour and finally becoming aggregated in irregu- 
lar masses of considerable size (Fig. 1, A, st). These 
finally are more or less completely digested by the 
fungus, but the nucleus of the host cell is in no way 
affected, and even where the cell is completely filled with 
the crowded hyphæ, the nucleus remains quite normal 
in appearance. 

The endophyte of Botrychium virginianum (Fig. 2) 
closely resembles that of Ophioglossum, but is somewhat 
smaller in all its parts and occupies the whole central 
region of the massive gametophyte. The two sorts of 


I . A, two cells from sral gametophyte of Botrychium virginianum, 
showing the two forms of the endophyte; B, a “ digestive” cell, showing the 
degenerating varicose mycelium of se ragga n, the nucleus of the 

cell ; Sek cell containing a conidium, con; D, fragment of one of the largest 
yphe; E, young conidium. All figures x 350. 


No. 495] SYMBIOSIS IN FERN PROTHALLIA 161 


cells, i. e., those with the filamentous hyphe (Fig. 2, A, 
x) and those containing the irregular vesicular mycelium, 
(y), are well differentiated, but are more or less irregu- 
larly mingled. The ‘‘conidia’’ (Fig. 2, C, con) are 
smaller and less numerous than in the endophyte of 
Ophioglossum, but have a much firmer membrane, as 
Jeffrey has described. These conidia were observed by 
Jeffrey to germinate by sending out a tube, and they 
are supposed to be special organs of propagation. 

In a very important study of the endophytic mycorhiza 
of the saprophytic orchid, Neottia, W. Magnus‘ has 
shown that two types of mycelium exhibited by the endo- 
phytes are of very different nature. The slender cylin- 
drical hyphe constitute the active portion of the fungus, 
which behaves like a parasite toward the cell which it 
invades, destroying the starch and probably other con- 
stituents of the cell, but not attacking the nucleus. The 
latter becomes much hypertrophied, a phenomenon that 
is not seen in the endophyte of the Ophioglossacee. The 
swollen vesicular mycelium, however, is a degenerating 
structure and is itself destroyed by the cells of the host, 
which actually digest these fungus mycelia in much the 
same way that the cells of Drosera digest their prey. 
Some interesting similarities in the behavior of the con- 
tents of the digestive cells of Drosera and those of these 
humus saprophytes have been demonstrated. Figs. 2, 
A and B, show some of these cells in Botrychium; the 
varicose mycelium has very delicate walls, and in the 
older cells (Fig. 2, B) they seem to be disintegrating until 
finally the structure is completely destroyed and only 
a structureless lump is left. In Neottia this undigested 
mass is ejected into a central vacuole and becomes sur- 
rounded with a more or less evident cellulose membrane, 
separating it entirely from the protoplast after diges- 
tion is complete. 

A comparison of the endophytes found in the green 

1 Studien an der Endotrophen Mycorhiza von Neottia Nidus Avis L. 
Pringsh. Jahrb., XXXV, 1900. 


162 THE AMERICAN NATURALIST [ Vou. XLII 


prothallia of the various ferns referred to shows some 
differences which are probably not without significance. 
The structure of the mycelium and its general behavior 
are so much like those of the endophyte occurring in the 
strictly saprophytic gametophyte of the Ophioglossacese 
as to leave little doubt that the endophyte in each case 


Fig. 3. Cells from the green aniar hey of several ferns, showing the 
character of the endophyte. All figu 50. 
A, Angiopteris evecta; B, ond gre kanoe, C, D, Gleichenia pectinata. 


is the same, or at any rate closely related. The conidia 
(Fig. 3, A, C) are perhaps less frequent, but in form 
and structure are very like those of Botrychium. The 
most noticeable difference is the apparently complete 
absence of the ‘‘digestive’’ cells, 7. e., those that contain 
the varicose swollen mycelium. No indications were 
noted of the destruction of the fungus by the cells of the 
host and the former is evidently much more nearly a 
true parasite than is the case in the saprophytic gameto- 
phytes. In the infested cells of the green gametophyte 
the starch and chromatophores are destroyed evidently 
by the action of the endophyte, but the nucleus remains 
intact. 


No. 495] SYMBIOSIS IN FERN PROTHALLIA 163 


Of the ferns with green prothallia, the endophyte has 
been found, almost without exception, in the following: 
Marattia Douglasu Baker, Kaulfussia esculifolia Bl., 
Angiopteris evecta Hoffm., Gleichenia (Eugleichenia) 
polypodioides Sm., G. (Mertensia) dichotoma Willd. 
(=G. linearis (Burm.) Bedd), G. (Mertensia) levigata 
Hooker, G. (Mertensia) pectinata Presl. In Osmunda 
cinnamomea it appears to be commonly but not always 
present, and in O. Claytoniana it could not be found. 
The number of slides of the last species examined was 
not very large and it is possible that further study of 
this species, as well as of O. regalis, will show its further 
occurrence in the Osmundaceæ. 

Of the forms that were. examined, that occurring in 
Osmunda and Gleichenia was the largest (Fig. 3, B, C) 
and equal in size to the endophyte of Ophioglossum. The 
form in Angiopteris was the smallest that was seen. 


THE SIGNIFICANCE OF THE ENDOPHYTE 


That the presence of the endophyte is necessary to the 
existence of all strictly saprophytic gametophytes is in- 
dicated by the failure of the germinating spores to 
develop unless they become associated with the fungus. 
Moreover, the universal occurrence of a similar endo- 
phyte in all humus-saprophytes among the seed plants 
indicates that in all of these chlorophylless plants the 
presence of the fungus is necessary for the existence of 
the host. Although it has not been directly proved, it 
is generally assumed that one réle of the endophyte is 
the elaboration of some of the carbonaceous constituents 
of the humus. The infrequent communication between 
the external hyphe and the internal mycelium makes it 
unlikely that the nutritive products are directly absorbed 
by the fungus, and it seems much more probable that the 
rhizoids of the gametophyte are the direct agents of 
absorption. How the humus constituents are changed 
by the action of the fungus so that they are available for 


164 THE AMERICAN NATURALIST [ Vou. XLII 


the cells of the host is not clear and it is by no means 
impossible that some at least of the necessary carbon 
may be derived from the fungus itself in the digestive 
process to which it is subjected in the digestive cells. 
This seems plausible from the fact that in green pro- 
thallia, where presumably the plant is entirely able to 
supply its own carbon compounds through photosynthesis, 
these digestive cells appear to be wanting; or at any rate 
they were not observed in the several forms that I have 
studied. The experiments of Ternetz already referred 
to showing that certain fungi, including certain endo- 
phytie mycorhize, have the ability to assimilate free 
nitrogen, confirms the assumption of earlier authors that 
the fungus is useful to the host in supplying to it nitro- 
gen compounds; but while this is probably a very impor- 
tant part of its functions, it seems to me that it is not 
perhaps the only one, and that the necessary carbon is 
also supplied directly or indirectly through the agency 
of the fungus. 

As Magnus has very graphically shown, the relation 
of the two symbionts is mutually antagonistic, each one 
acting as a parasite on the other, but nevertheless the 
presence of the fungus is essential to the higher organ- 
ism so long as the latter is destitute of chlorophyl; and 
the explanation of the wide-spread saprophytism exhibited 
by so many of the higher plants may be sought in this 
attempt to defend themselves against what was probably 
at first a strictly parasitic organism. Having acquired 
the power to attack and feed upon the parasite, the photo- 
synthetic functions were more and more subordinated 
until a state of true parasitism (or saprophytism) re- 
sulted. The numerous semi-saprophytes like most of 
the green Ericaceæ and many green Orchidacew are good 
examples of transition stages, while the characteristic 
leafless humus saprophytes, such as the Monotropee and 
the chlorophylless Orchidaceæ, represent the fully de- 
veloped phase of this peculiar form of symbiosis. 


No. 495] SYMBIOSIS IN FERN PROTHALLIA 165 


That this symbiotic association may occur in still lower 
organisms than the ferns is shown in the familiar case of 
the lichens, which are most perfect examples of this. It 
has been shown also that a similar association of fungus 
and host occurs in a good many liverworts. Cavers® has 
studied this association with some care in the common 
liverwort Fegatella, as well as in other Hepatice. He 
found in Fegatella that the endophyte is beneficial to the 
growth of the host, the plant being more vigorous when 
the fungus was present. He assumed that this was due 
to the assistance given by the fungus in the assimilation 
of organic matter from humus or from other organic 
substrata. 

This frequent occurrence of an endophyte in Hepatice 
makes the occurrence of this in the green prothallia of 
ferns quite readily understood. Whether in the latter it 
is an advantage to the host to have the endophyte present 
remains to be seen, but it is highly probable that such is 
the case. Once having acquired the habit of associating 
itself with the fungus, the gradual development of the 
purely saprophytic subterranean gametophytes of the 
Ophioglossacee from green forms similar to those of the 
Marattiacex, is readily conceivable. In the genus Lyco- 
podium there is every degree from the strictly holophytic 
green prothallium of L. salakense to the subterranean 
chlorophylless gametophyte of L. clavatum or the still 
more specialized gametophyte of L. phlegmaria. 

Presumably in the Ophioglossacex the evolution of the 
gametophyte eis been very much the same as in Lyco- 
podium. 

*On Saprophytism and Mycorhiza in Hepatice. New Phytologist, TI, 
1903 : 


THE EVOLUTION OF THE TERTIARY MAMMALS, 
AND THE IMPORTANCE OF THEIR 
MIGRATIONS? 


PROFESSOR CHARLES DEPERET 
UNIVERSITY oF Lyons 


Seconp PAPER. OLIGOCENE Hpocu? 


Havine analyzed the local evolution and the migrations 
of the Eocene mammals (Comptes rendus, 6 novembre, 
1905), I will now consider the corresponding data in 
regard to the Oligocene. 

B. Oxvigocrnt Faun. 

I. Lower Oligocene (Sannvisian or Lower Tongrian). 
Two successive faune: 

(a) Fauna of the white marl of Pantin, Romainville. 
The fauna of the lignites of Célas, Avéjan, Vermeil 
(Gard), of the limestone of Brunstatt and of Rixheim 
(Alsace) are probably not very distant from this. With- 
out doubt the same is also true of several deposits in the 
South West of France: Fronsac and la Grave (Gironde), 
Sainte-Sabine, Duras, Issigeac, Saint-Cernin (Dordogne). 
A part of the phosphorites of Quercy,® and of the ‘‘ter- 
rain sidérolithique’’ of Fronstetten (Suabia) belong to 
the same level. 

1. Local Evolution.—Continuance of the Paleotheriide 
(Paleotherium, Plagiolophus), of the Anoplotheride (last 
of Anoplotherium), of the Xiphodontide (last Xipho- 
don), of the Rodentia—Theridomyide (Theridomys). 

1 First paper, Eocene Epoch, in the February number of the NATURALIST. 

2 Extract from the Comptes rendus des séances de l’Académie des Sci- 
ences, t. CXLII, p. 618 (séance du 12 Mars, 1906). Translated by Johanna 
Kroeber. 

3 The remarkable fauna of the phosphorites is not a homogeneous assem- 
blage, but a composite representing horizons from the Bartonian to the 
Stampian, inclusive. In general, therefore, I shall consider only those 
genera of the phosphorites that have been found elsewhere in the stratified 
deposits, and whose age can thus be positively determined. 

166 


; 


No. 495] EVOLUTION OF TERTIARY MAMMALS 167 


2. No new migration is known. 

This fauna seems to be simply a much-reduced remnant 
of the Ludian fauna and should be more properly included 
with the upper Eocene. 

(b) Fauna of the limestone of Brie, of Hempstead 
(Isle of Wight), of Ronzon (Velay), of Lobsann (Alsace), 
of Calaf and Tarrega (Catalonia). A part of the phos- 
phorites of Quercy and of the ‘‘terrain sidérolithique’’ 
(Bohnerz) of Veringendorf, Veringenstadt, of the Esels- 
berg, of the Hochberg and of Oerlingerthal near Ulm, 
belong to the same horizon. Possibly the beds of Monte- 
Promina (Dalmatia) belong to this horizon or to the pre- 
ceding one. 

1. Local Evolution.—Continuance of the Paleotheriide 
(Paleotherium, Plagiolophus), of Anthracotheriide (con- 
tinuance of Brachyodus, and appearance of species of 
Ancodus, some species of Anthracotherium), end of the 
Anoplotheriide (last Diplobune), continuance of Cenothe- 
riidæ (Amphimeryx, ? Cenotherium), of Canidæ (Cynodon, 
Cynodictis, Amphicynodon), of Erinaceide (Tetracus), 
of Theridomyide (Theridomys), of Hyænodontidæ (Hyæ- 
nodon), of the Marsupial Didelphyide (Peratherium 
Amphiperatherium). 

2. Important North American migrations: Sudden ap- 
pearance of the Rhinocerotide (Ronzotherium), and of 
the Entelodontide (Entelodon). 

3. Migrations of unknown origin of the Tragulide 
(Gelocus), of Mustelide (Proplesictis), of the Myomorph 
Rodentia (Cricetide), and perhaps of the Amphicyonine 
(beds of Tarrega). 


II. Middle Oligocene (Stampian or Upper Tongrian), 
very numerous deposits: in the Paris basin, la Ferté- 
Aleps; in Germany, Ufhofen, Flonheim, Miesbach, lig- 
nites of Schluchtern, of Gusternheim and of Westerwald; 
in the basin of 1’Allier, Bournoncle-Saint-Pierre, Bons, 
Perrier, Montaigut-le-Blanc, Champeix, Autrac, Saint- 
Germain-Lembron, Antoingt, Vodable, Solignat, Lamont- 


168 THE AMERICAN NATURALIST [ Vou. XLII 


gie, Nonette, Orsonnette, Malhat, Les Pradeaux, Les 
Chauffours, Bansat, Boudes, Chibrac, La Sauvetat, Jussat, 
Gergovia, Romagnat, Pérignat, Lemdes, Cournon, Mar- 
coin, Chaptuzat, Gannat, Saint-Menoux; in the basin of 
the Loire, Vaumas, Saint-Poureain-sur-Bébre, Briennon, 
Digoin; in the South East of France, Céreste, Manosque, 
clay of Saint-Henri near Marseilles, les Milles near Aix, 
Auzon near Alais; in the South West of France, Cestayrol, 
Saint-Sulpice, Rabastens, hill of Saint-Martin, Montans, 
Salvagnac, VIle d’Albi, Pont-Sainte-Marie, Tournon, 
Capellier, Les Péries, Villebramar, la Milloque, Combera- 
tière, Moissac, Beauville, Itier, Bourg de Visa, Montségur, 
ete.; in Switzerland, Blauen, La Conversion, near Lau- 
sanne; in Italy, Cadibona in Liguria, Monteviale and 
Zovencedo in Vicenza; in Austria, Trifail in Styria, and 
deposits in Dalmatia; lignites of Inca (Island of. Ma- 
jorea) ; the larger part of the phosphorites. 

It seems that from now on it will be possible to distin- 
guish at least two horizons in this important stage: the 
lower (the principal deposits of which are given in italics 
in the preceding list), characterized by the persistence of 
the last representatives of Paleotherium, of Entelodon, 
or of Gelocus; the upper by the abundance of large-sized 
Anthracotherium and Acerotherium, and the sudden ap- 
pearance of the Tapiride. 

For the stage as a whole, the facts in regard to evolu- 
tion and migration are as follows: 

1. Local Evolution. — Continuance of Paleotheriide 
(last appearance), of Rhinocerotide (A therium, Di- 
ceratherium), of Chalicotheriide (Schizotherium), of 
Anthracotheriide (Brachyodus, Anthracotherium, several 
phyla), of Entelodontide (last Entelodon), of Suide 
(Propalzocherus, Paleochcrus), of Cenotheriide (Czno- 
therium, Plesiomeryx), of Tragulide (last of Gelocus, 
Prodremotherium, Lophiomeryx), of Theridomyide (The- 
ridomys, Issiodoromys, Archeomys), of Cricetine (Cri- 
cetodon), of Talpide (Geotrypus), of Erinaceidx (Erina- 
ceus), of Chiroptera (Paleonyeteris), of Creodonta (last 


No. 495] EVOLUTION OF TERTIARY MAMMALS 169 


Hyzenodon and last Pterodon, Dasyurodon), of Canidæ 
(Amphicyon), of Mustelide (Plesictis, Paleogale), of 
Viverridæ (Amphictis), of Marsupialia (Peratherium). 

2. Migrations of North American origin of Tapiride 
(Protapirus, Paratapirus), and of Amynodontide (Ca- 
dureotherium*), and perhaps of the Felide-Macherodine 
(Kusmilus). 

3. Migration probably from Africa (and perhaps a 
little before the Stampian), of Edentata with normal ver- 
tebræ (Leptomanis and Archæorycteropus of the phos- 
Phoria beds).° 

4. Migrations of unknown origin of Cervuline (Dremo- 
arlam, Amphitragulus), of Castoridæ (Steneofiber), of 
Myogalidæ (Echinogale, Myogale), of Tupaiidæ (Plesio- 
sorex), of Soricidæ (Amphisorex, Sorex), of Lutrinæ 
(Potamotherium), of the Felidæ-Proælurinæ (Pseudæ- 
lurus), and of Lagomorph Rodentia (agomyids, genus 
Titanomys). 

II. Upper Oligocene (Aquitanian). 


Principal deposits: in the Paris basin, Celles-sur-Cher ; 
in the Bourbonnais, Saint-Gérand-le-Puy, Chaveroche; in 
Germany, Weissenau and Mombach near Mainz, Haslach, 
Kekingen near Ulm; in Switzerland the Gray Molasse of 
Lausanne, Othmarsingen, Hohe Rhonen; in Savoy, Pyri- 
mont-Challonges; in Provence, Varages (Var); Boujac 
in the basin of Alais; in Catalonia, Rubi near Barcelona; 
in Bohemia, Tuchoritz; in Karinthia, Keutchach; in Hun- 
gary, Waitzen. 

1. Local Evolution.—Continuance of Tapiride (Para- 
tapirus), of Rhinocerotide (Aceratherium, Dicerathe- 


*M. Boule (Comptes rendus, 18 mai, 1896) has endeavored to prove an 


as Astrapotherium; this relationship would be interesting, i 
strated, for it would imply a Patagonian migration in the Oligocene period. 
But the supposed affinity st in my opinion, upon rather superficial 
resemblances of the dental sy 

"I do not believe in the ithe of South American Edentata in the 
Oligocene of the phosphorite beds. The Necrodasypus of Filhol seems to 
me to be a dermal plate of a Reptile related to Placosaurus Gervais. 


170 THE AMERICAN NATURALIST [ Vou. XLII 


rium), of Chalicotheriide (Macrotherium), of Anthraco- 
theriide (Brachyodus, last of Anthracotherium), of Suid 
(Paleochcerus, ? Doliochcrus), of Canotheriide (Czno- 
therium, Plesiomeryx), of Cervuline (last Dremotherium 
and Amphitragulus), of Theridomyide (Theridomys), of 
Myoxide (Myoxus), of Eomyide (Rhodanomys), of 
Sciuride (Sciurus), of Castoride (Steneofiber), of Lago- 
morph Rodentia (Titanomys), of Talpide (Talpa), of 
Soricide (Sorex), of Erinaceide (Paleoerinaceus, Eri- 
naceus), of Canide (Amphicynodon, Cephalogale), of 
Amphicyonine (Amphicyon), of Mustelide (Stenogale, 
Plesictis, Paleogale), of Lutrine (Potamotherium), of 
Viverride (Amphictis, Herpestes), of Felide (Prozlu- 
rus), of Marsupialia (the last European Didelphyide). 

2. Smaller migrations of unknown origin of the Dimy- 
lide (Dimylus, Cordylodon). 

The Aquitanian fauna is chiefly an impoverished resi- 
due of the Stampian. 


Important migrations begin again with the Miocene 
epoch, and these will form the subject of a later paper. 


OBSERVATIONS REGARDING THE CONSTANCY 
OF MUTANTS AND QUESTIONS REGARDING 
THE ORIGIN OF DISEASE RESISTANCE 
IN PLANTS! 


PROFESSOR HENRY L. BOLLEY 
Nortn DAKOTA AGRICULTURAL COLLEGE 


Ir is not my purpose to develop a controversy as to 
theories, but, in pointing out some features of my studies 
upon disease resistance, it seems necessary to raise some 
question concerning the rapid development of the muta- 
tion theory which I believe to be worthy of close thought 
before we accept this theory as replacing, in entirety, the 
- doctrine of evolution as formulated by Darwin. 

The DeVriesian school has pointed out one way in 
which plants and animals originate new individuals with 
characteristics apparently new. The Mendelian formu- 
las, especially as in late years developed, illustrate clearly 
how apparently new characteristics may appear to be 
caused to arise. This would seem to be a fair statement 
of all that has actually been accomplished. 

I assent that most of the conceptions arising from the 
investigations of Mendel and DeVries are probably cor- 
rect and, after considering expositions depending upon 
the experiments of many workers and having experi- 
mented sufficiently to understand the meaning of ‘‘mu- 
tants,’’ ‘‘unit characters’’ and ‘‘elementary species,’’ I 
recognize that these works added much light upon how 
evolution in plant life takes place, and that henceforth 
the conception of unit characters must largely form the 
theoretical working basis for practical breeding work. 
Yet I feel sure that Darwin’s conception was sufficiently 
broad to embody both features as minor parts of the 
great concept of organic development. To accept De- 

i Read before the American Breeders’ Association, Washington, D. C., 
January 29, 1908. 

171 


BY THE AMERICAN NATURALIST [ Von. XLII 


Vries’ doctrine of mutation as a substitution for the 
Darwinian conception is, I believe, to accept a part for 
the whole and to place before the farmer and stockman 
a doctrine which, if generally accepted as a substitute for 
the broad conception of Darwin, can not but be narrow- 
ing and injurious. : 

DeVriesian and Mendelian phraseology, in daily use, 
may be to blame, but in reading many of the late exposi- 
tions one is led to question whether the doctrine of con- 
stancy of elementary species or constancy of unit char- 
acters can be accepted by biologists and breeders with 
any less damage to after progress than that which fol- 
lowed the once complacent acceptance of the Linnean 
dogma of the constancy of species. 

DeVries, of course, argues for the acceptance of the 
validity of evolution by mutations, and while one may 
readily concur that such mutations occur, one who works 
largely with cereal crops and has always recognized that 
the individual is the proper starting point for selection 
work, is apt to be astonished in reading his new work on 
‘Plant Breeding,’’ and falls to questioning whether 
after all, a mutation may not be merely a ‘‘fluctuating 
variation,’’ big enough and stable enough to be recog- 
nized. Is it possible that the nature of these changes is 
different in kind or only in quantity and range of dura- 
tion? Does accident play so large a part in plant de- 
velopment and plant breeding as indicated by most 
DeVriesian writers? One need not object because of the 
wonderful things said of elementary species, for good 
Darwinians have always believed in the existence of 
strains and subspecies which would admit of the name; 
nor should we expect any less of DeVries than that he 
should use the arguments related in ‘‘Nilson’s Dis- 
covery’’ and those from such other experiments and ex- 
positions as would, when handled in certain lights, tend 
to show evolution by mutation. Yet, one who recognizes 
all of the possible merits that accrue from the concep- 
tion of hypothetical unit characters and of the existence 


No. 495] CONSTANCY OF MUTANTS 173 


of plant strains which admit of the designation ‘‘ Ele- 
mentary Species’? may be pardoned if he is unable to 
accept another dogma of constancy, and is unable to sub- 
scribe to many DeVriesian conclusions regarding the 
comparative merits of mutation as opposed to adaptation 
and natural survival. Most of us, I believe, can only look 
upon a mutation as one of the types of variation through 
which the survival process brings about evolution. I 
believe that we still have to look for the underlying causes. 
An ardent Darwinian can well agree to the statement: 
‘“Species are derived from other species by means of 
sudden small changes which, in some instances, may 
scarcely be perceptible to the inexperienced eye,” °? but. 
may find points of doubt and refuse to follow to the 
limit when reading a number of statements found in the 
same work, for example, ‘‘From their first appearance 
they are uniform and constant.” This statement refers 
to species. Again, ‘‘The conception of mutations agrees 
with the old view of the constancy of species. This 
theory assumes that a species has its birth, its lifetime, 
and its death, even as an individual, and that throughout 
its life it remains one and the same.’’* ‘‘Each single 
type (be it species or subspecies or variety) is thus wholly 
constant from its first appearance and until the time it 
disappears either after or without the production of 
daughter species.’’® This last sentence is certainly clear 
to the effect that a species is never changed, at least so 
as to affect its after progeny. It is equivalent to saying 
that all individuals after formation in the seed remain 
exactly like the parents and, taken with the other state- 
ments which insist that plants mutate, means that they 
remain constant until they change, which is an absurdity 
in argument. With this, we must assume that a man can 
recognize ultimate unit characters and can recognize just 
how many characters it takes to make a species. When 
2 DeVries. Plant Breeding. Page 9. 


5 Ibid., page 9. 


174 THE AMERICAN NATURALIST [ Vou. XLII 


we can do this, there will not be any use for the Breeders’ 
Association. ‘‘... Mutations occur constantly, without 
preparation and without intermediates.’’® I can not think 
of a mutation or change in species occurring without prep- 
aration and without intermediates. It is equivalent to 
saying without cause. Later, one reads, ‘‘We may con- 
fidently assume that each single mutation affects only 
a single unit.’ I would certainly agree with this state- 
ment if I could conclude from the author’s other state- 
ments that he had in mind that a plant might be made up 
of an inconceivable number of unit characters, the ulti- 
mate nature of which may, after all, be only matters of 
force. ‘‘In other words, the principle of adaptation, as 
one of the main parts of the theory of evolution, should 
be separated from the study of the geographical distri- 
bution. ...’’® As to this assertion, I agree that plants 
migrate and select in the same sense that men migrate 
and select, but I can not agree that a species never adapts 
itself in such form as to transmit the results of adapta- 
bility. 

‘Environment has only selected the suitable forms 
from among the throng and has no relation whatever to 
their origin.’’® ‘‘Natural selection . . . causes survival 
of the fittest; but it is not the survival of the fittest of 
individuals, but that of the fittest species, by which it 
guides the development of the animal and vegetable 
kingdoms.’’!° 

These last two quotations contain sweeping assump- 
tions and all of them taken together must be interpreted 
as saying that evolution in plant and animal life arises 
wholly from accidental changes, that is, from mutations 
which are matters of accident, having no preceding 
cause, therefore beyond us as breeders to investigate or 
change. This would naturally deprive agriculturalists 

*DeVries. Plant Breeding. Page 24. : 

T Ibid., page 322. 

* Ibid., page 345. 

* Ibid., page 352. 

1 Ibid., page 9. 


No. 495] CONSTANCY OF MUTANTS 175 


and stockmen of the right to hope for the adjustment of 
a species to new surroundings in which at first it does 
not fit. 

It is hard to comprehend a philosophy which recognizes 
the old conception of species yet breaks it into countless 
‘‘elementary species,’’ and at the same time claims abso- 
lute constancy for the characters of the elementary forms. 
If mutations, which all agree may occur, do not come from 
irritations of environment, internal or external, from 
what cause may they arise? Must we say that each plant 
with an observable unit character is a species and, with 
Linneus, that it always was? My observations do not 
allow of this thought; neither have I ever seen an acci- 
dent in nature. The only observed accidents of nature, 
when known, have ‘always been found to have direct nat- 
ural causes.. I could not work with faith upon plant breed- 
ing if I could convince myself that any plant was ever 
the result of an accident. 

The fact that plants mutate and that new types arise 
in regular mathematical relations due to cross breeding, 
and that selections from individuals give the correct 
methods of breeding, seems evident, but I have seen noth- 
ing to convince me of absolute constancy of either indi- 
vidual or species. Mutation seems to be just a good name 
for a grade of natural changes and no more. We have 
still to look for the causative feature in the environment 
behind the mutation or change of character; and, if we 
wish to improve upon agricultural species or varieties or 
individual strains, we must select from among the occur- 
ring changes, whether we call them mutants, elementary 
species or unit characters. The demonstrations of mu- 
tations and the new knowledge that arises from a better 
understanding of the laws governing union of and correla- 
tion of characters must eventually greatly facilitate the 
studies looking toward an understanding of direct special 
causes for the changes which occur in the evolution of a 
type. DeVries’ original experiments were of immense 
value, but I believe his philosophy of constancy to be 


176 THE AMERICAN NATURALIST [ Vou. XLII 


exceedingly bad. There seems to be no observation or 
experiments which can be interpreted as substantiating 
that phase of his writings. While DeVries’ examples all 
point to the minutest types of variation and change, 
his philosophy of constancy is directly opposed to this 
thought and would dash all of the hopes of the average 
man doing any work looking toward the improvement of 
strains, or types. Yet, previous to the last few years, 
since college men have been given sufficient funds for 
experiment, it was the practical farmer and stockman 
who had done the work in improvement of agricultural 
sorts and races in stock, and most of the improvements 
have been made from pedigreed strains of rather pure 
type whether we speak of vegetables, fruits, cereals or 
eattle. I know this statement will meet with objections, 
but I believe it will be found to stand upon good bases 
when we remember the work of our horticulturists and 
best breeders of animals. For example, Wellman, Haynes 
and Houston used plant gardens for the production of 
individuals from individual mother plants in wheat be- 
fore De Vries, Nilson or Hayes worked. I can not con- 
vince myself, after studying the results and observing 
the work of Mr. Haynes in later years, that he or the 
other two men got results only from their first selections. 
Each of these men have time over and again told me 
that they selected only the best strains from the progeny 
of the best individual and that each year their crop had 
improved in the direction along which they worked and 
that it maintained itself reasonably well in the field. 
This, of course, DeVries would answer was only the re- 
sult of ‘‘fluectuating variations.’’ My studies do not con- 
vince me that he is correct. Undoubtedly, there are 
countless variations which may occur in the field crop 
which it is folly to assume may be detected and classi- 
fied as permanent or fluctuating. Certain it is, that 
Darwin argued for the great ‘stability of certain inbred 
stocks and that forces of heredity are stronger than those 
of variation. It is equally true that the longest pursued 


No. 495] CONSTANCY OF MUTANTS 177 


experiments of American agriculture show that pure 
strains or varieties of close-bred stocks, especially those 
of cereals, are sufficiently stable to be held to form under 
intelligent culture, but none of us, as yet, can say further 
than this. If we maintain and can agree that a mutation 
or change has a natural cause and that no plants are 
stable, constant in character, it is nevertheless not neces- 
sary to be assumed that the burden of proof rests en- 
tirely upon Darwinians. © : 

What evidence may be placed over against the theory 
of constant elementary species? Well, as an hypothesis, 
when carried to the limit, an elementary species becomes 
a unit character and when unit characters are well known 
they will as in the case of the units of matter, perhaps 
become so intelligible as to be recognized as the least 
conceivable element of natural force which makes for 
union and which in case of the organic units may make 
for a heritable change. This, the writer believes, is the 
ultimate result to which most of DeVries’ facts and ob- 
servations point, and my own observations, together with 
those of others, as I undestand them, teach that when- 
ever physical and chemical conditions are changed in 
the least, within or without the plant, some variation 
will occur in plant substance, and that this may result 
in a change in the progeny which may be fixed or modi- 
fied sufficiently to serve agricultural purposes, if the con- 
ditions which originate it may be ascertained and reason- 
ably maintained. It is but reasonable that some changes 
should approach greater stability than others. 

The practical breeders of America, years before the 
work at Amsterdam and Svalof commenced, developed 
hundreds of varieties; and though I have worked with 
many varieties and strains of wheat, flax and potatoes 
and have found them all reasonably stable if given gen- 
erally stable environment, I have never yet been sure 
that I have seen a stable plant or stable strain or variety. 
Some change is continually taking place and any change, 
I think, may be fixed just in proportion as we know the 
conditions which originate it. ; 


178 THE AMERICAN NATURALIST [Vou. XLII 


This brings me to the statement of a principle of agri- 
cultural cropping which, though generally recognized by 
breeders for years, yet needs to be much emphasized by 
those who would improve a character of a plant or a 
plant strain, or maintain a standard of a general crop; 
namely, the condition under which a character originated 
or is being originated must be maintained or approached. 
It is all the more important to hold this feature of crop- 
ping well in mind, now that the conception of unit char- 
acters and of mutations and of new methods of experi- 
mental breeding has proved to be of such fertile aid 
in the production of new types. Much of the value of 
agricultural, commercial cropping rests upon the per- 
manence and general use of a few well-maintained or 
established varieties as against the miscellaneous use 
of many varieties; thus, for instance, a district or country 
gains its reputation for a particular crop not by the use 
of many varieties, as, for example, of wheat, or oranges, 
but by the use of a few which by careful work are held 
to their cl teristic qualities. It is quite possible to 
swamp agriculture by the creation of too many forms. 
Stable industries are built up about reasonably stable 
crops. 

After a new type or a new character in a type has been 
obtained, new conditions, if they include the essentials 
of the old conditions, may readily bring about the ad- 
dition of new features whether we have in mind calling 
these new features fluctuating or elementary. If the 
originating conditions are lost or are not maintained, the 
type should degenerate or retrograde, lose character, and 
I am quite convinced that it always does. Herein lies 
the working basis for every-day cropping and breeding. 
This line of argument is equivalent to saying that so- 
called fluctuating variations may be maintained and built 
upon as foundations for important hereditary changes, 
whether, in writing, we term the resultants mutants, 
sports or simply elementary units or species. Itis equiv- 
alent to arguing that the principle of adaptation may 


No. 495] CONSTANCY OF MUTANTS 179 


be active in nature even though mutations are observed. 
Or, perhaps plainer, it is equivalent to saying that muta- 
tions themselves may be nothing more or less than adap- 
tations, adaptive changes. I think breeders who ignore 
this thought in their work will eventually find themselves 
without a basis for well-founded experiments. 

I have been brought to these conclusions chiefly through 
careful observations upon my own selection and breeding 
plots, upon which for a number of years, I have attempted 
to hasten the survival of the fittest, or of the unlike, 
through the development of or heightening of the action 
of plant disease for the purpose of eliminating the weak 
or unfit.1! The method of field work consists essentially 
in constant culture or cropping to the crop under con- 
sideration and in promoting, in every way possible, the 
development and action of the disease under considera- 
tion; and at the same time using all available methods 
of breeding and selection under these heightened condi- 
tions of disease. The method has given marked results 
when applied to wheat vs. wheat rust; wheat vs. wheat 
smut; flax vs. flax rusts; flax vs. flax wilt; and potatoes 
vs. scab and blight. 

My observations along these lines have been such that 
I have'no fear but that the future will find me right in 
the assertion (1) that mutants may be so insignificant 
and numerous as to be unrecognizable and thus fall di- 
rectly into the class called by DeVries, ‘‘fluctuating vari- 
ations’’; or (2) that they may be induced in a mixture 
of a great number of varieties of a species at one and the 
same time because of the same environmental causes; or 
(3) that, in some cases, ‘‘fluctuating variations” are of 
such nature and worth as to allow results to be obtained 

“The full details of the methods and details of the results can not be 
furnished in the limits of this paper. The method of work has been out- 
lined in the annual reports of the North Dakota Agricultural Experiment 
Station and in an address delivered before the meeting of farmers and 
stockmen at St. Louis, October, 1903, and further reported upon in vol. 
I, page 131 of the report of this association, and also in the Proceedings 
of the Lansing Meeting of the Society for Promotion of Agricultural 
Science, p. 107, 1907. 


180 THE AMERICAN NATURALIST [ Vou. XLII 


in mass breeding of as great importance as any that may 
be hoped to be obtained by looking for a single mutating 
type evolved through the method of DeVries. 

I am unable to affirm whether disease resistance, im- 
munity to disease, is structural or physiological. I be- 
lieve the latter, for I have been able to develop it in 
varying degrees of perfection in every strain of potatoes, 
wheat or flax with which I have worked, and for all of 
the diseases noted, while the method used has always re- 
mained the same. There is also good structural evi- 
dence that it is physiological, as shown in the structural 
changes caused by the entrance of disease-producing 
organisms within the tissues of resistant hosts. I 
have worked with pure strains, centgener progeny, 
from individuals, with the progeny of cross bred plants, 
with mixed strains and variations in bulk, and with 
bulk selections of centgener origin, side by side, and 
resistance has come at approximately the same rate 
and grade for a variety through any one of these methods. 
When the conditions of disease production and conditions 
of infection for each plant have been held so as to be 
constant factors, the bulk method of selection, as, for ex- | 
ample, selection to seed weight, color and form from a 
disease plot of flax, has given final hereditary resistance 
as rapidly as individual selections from the progeny of 
individuals of the same strains. The only cases in which 
resistance has developed irregularly in such strains of 
flax or wheat have been found to be due to impurity of 
type or to irregularities as to the constancy and amount 
of disease infection, or to irregularities in the conditions ` 
promoting the development of disease. : 

Resistance to the diseases named for the crops named 
can be developed in any variety or strain by either 
method of selection noted. In any case, it may be in- 
creased by every proper selection year by year, just in 
proportion to the perfection with which the disease con- 
ditions of elimination are maintained. 

The method works in potato selection, where the process 


No. 495] CONSTANCY OF MUTANTS 181 


of propagation is by cuttings or buds and hence only a 
condensed individual life. It works in wheat, which seems 
quite guarded in its closed or individual fertilization. 
And it works in flax which, though usually self-fertilized, 
is, no doubt, much given to intercrossing in the open. 

If the proofs rested only upon flax, where there are 
many possibilities that open crossing might give rise to 
the various Mendelian types, homozygotes, heterozygotes, 
etc., the evidence might be thought to be thrown into 
question, but even there, when crossing is promoted, 
while there is every evidence of the occurrence of resist- 
ant or non-resistant types among the crosses, resistance 
is seldom found to approach the immune type upon the 
first possible selection. In other words, if mutants do 
occur in flax through natural crossing or self-fertilization, 
so far as our experiments are concerned, these resistant 
forms are found to act exactly as do those which may be 
developed from ordinary types of non-resistant flax. 

With this crop, one finds little, if any, resistance to 
wilt and to rust in the best seed strains of southern 
Russia or in the best seed strains from the new lands of 
our northwest or in the best fiber strains of the disease- 
free districts of northwestern Russia, though it often 
crops out in the general seed samples from the worst 
disease infection regions of central Russia. If mutants 
were without cause and constant, one ought to find them 
as readily in the seed of one district as in another. One 
can, however, build resistance upon the least resistant 
of these strains, if the work is started upon a graded 
seale of disease infection which is increased year by year. 
If the seed is placed under too heavy conditions of wilt 
production, the plants are all killed in embryo or young 
stages of growth and nothing is gained. If, however, 
scrubs or runts may be saved from the first season under 
weak disease infection and a graded infection is followed 
thereafter, in approximately five years one may bring 
these strains of seed to such a stage of resistance that 
ordinary agricultural methods of cropping will maintain 


182 THE AMERICAN NATURALIST [Vou. XLII 


them upon the most flax-sick areas. But whether these 
resistant strains have been selected through crossing or 
by this gradation method from bulk seed or from indi- 
viduals taken from a known pure strain, I have found 
that abrupt heightening of disease conditions of too great 
violence may undo the whole work. 

It holds as well for wheat when speaking of rust at- 
tacks. Under uniform conditions of rust infection, all 
wheats arise rapidly to a stage of marked resistance to 
general uredospore infection whether caused by the type 
Puccima graminus or P. rugigo-vera, which resistance 
seems to be characteristic for each variety concerned, 
but may then fall a ready prey to sudden attacks in- 
troduced by properly conducted aecidial infection. All 
this points to the réle played by the irritations of environ- 
ment, which either govern the appearance of mutations 
or produce other changes which are very worthy of the 
breeders’ and croppers’ attention; and allows one to as- 
cribe much more merit to methods of mass selection and 
breeding in cereals than the DeVriesian doctrine of con- 
stancy of elementary species will allow one to assume. 

No phase in this argument touches upon the ultimate 
causes of disease resistance or immunity. But the facts 
do point quite clearly to the probable influence of chemi- 
cal agencies, perhaps toxines, arising from the direct 
existence of fungus attacks upon the hosts. In my mind, 
there is not the slightest doubt but such attacks originate 
heritable resistance, in much the same sense as Mac- 
Dougal’s chemical injections upon ovaries are supposed 
to have originated new types. If later experiments prove 
MacDougal’s observations to be well founded, the results 
will be of far reaching importance. If these suppositions 
that fungus attacks upon the host may induce fungus- 
resistant qualities in the progeny from the matured ova- 
ries, are correct, no doubt the unit characters, so called 
(whether simple and definite in number or whether they 
may be considered as composed of countless and variable 
elements of the cromatin structures) may be effected, or 


No. 495] CONSTANCY OF MUTANTS 183 


may be originated, and one ought, under crossing, to 
observe the effects in terms of dominant and recessive or 
cloaked features. Such effects I have observed to occur 
in flax as against flax wilt and in wheat as against P. 
graminus. Mr. R. H. Biffin, of England, is reported as 
indicating. that this is true in the case of wheat when 
crossed with eincorn as against yellow rust. 

Bateson, in an admirable article upon ‘‘Facts Limit- 
ing the Theory of Heredity,’!2 would also seem to en- 
roll himself as against any adaptative response to 
changed conditions as able to account for the origin of 
such facts as I have observed in my cultures of flax and 
wheat. Thus we read: 

‘‘Though the response to change of conditions may have been 
direct, it must not be hastily concluded that the response is adaptive. 
The appeal to direct responses so common in evolutionary discussions 
of thirty years ago, was made to account for the complex adaptations 
of organism to environment. It is the total want of any evidence 
supporting that appeal which has driven most of us to disbelieve in 
the reality of any such claims, and there is nothing in the new evi- 
derice, I think, which should shake the attitude of resolute agnosti- 
cism which we have thus been led to adopt.’’ 

However, to explain such observations as those noted 
by me in the flax and wheat cultures seems to demand 
the assumption that additional elements of heritable char- 
acter arise on account of causes demanding adaptive re- 
sponse. No theory of quantitative subtractions of unit 
characters already formed would seem to be adequate 
to account for the observed acquired qualities of resist- 
ance. It is probable that only the cytologists are in 
position to produce direct proof or disproof of the 
apparently necessary suppositions as to character modi- 
fications. Certainly those among them who are experi- 
mentally inclined may cut along the line indicated with 
much hope of uncovering many high lights to breeders. 
Even here, it may be expecting quite too much that pos- 
sibly pure physiological qualities should be represented 
by structural units. 

12 Science, November 15, page 649. 


WHAT IS A SPECIES?! 
PROFESSOR S. W. WILLISTON 
UNIVERSITY OF CHICAGO 


We have had in the past not a few interesting discus- 
sions upon or controversies over the methods of evolu- 
tion and the origin of species in this club. We have more 
or less plausible theories as to the evolution of species, 
by natural selection, mutation, inheritance of acquired 
characters, etc., but we have very nebulous ideas as to 
what species really are. Nothing is more common than 
the term species; nothing is more uncertain than what 
species are. 

Long after the present topic had been suggested for 
discussion by the club, I was delighted to learn of a like 
discussion to be held at the late meeting of the Botanical 
Society in Chicago. I anticipated that symposium with 
the liveliest feelings of satisfaction, confidently expect- 
ing a brilliant illumination of the whole umbrageous sub- 
ject, an effulgence of light that would throw into deepest 
obscurity whatever feeble beams I might myself hope 
later to cast upon it. But lamentable was my disappoint- 
ment, I heard some ancient platitudes that the zoologists 
ceased in despair to consider a dozen years agone, and 
many anathemas showered upon the botanical taxono- 
mist. They berated him for making such a mess of classi- 
fication, and hinted very freely that he didn’t know much 
anyhow, and probably never would. If all that was said 
be true, then indeed the botanical taxonomists are a 
sorry lot. One distinguished speaker declared they had 
made no progress since the time of Linné, and he rather 
seemed to desire that the whole tribe might be banished to 
some desert isle where there is neither vegetable life nor 
printer’s ink, that they might no longer trouble the ecolo- 

1 A paper read before the Biological Club of the University of Chicago. 

184 


No. 495] WHAT IS A SPECIES? 185 


gists and physiologists, et id genus omne. But I can not 
escape a harrowing doubt as to what the learned speakers’ 
vocations in botany would be, if the maligned taxonomists 
had not got in their diabolical work. Possibly they would 
distribute an herbarium with each lucubration, that their 
readers might know what they were writing about; or 
possibly they might undertake to name their own species, 
for I have seldom known the morphologists to escape the 
mihi itch on very slight infection. 

I sympathize with the physiologist or ecologist, who 
after he has written a luminous paper on a Crategus or 
Viola, or Rosa, or Opuntia, endeavors to ascertain the 
proper name for his plant; but I do not sympathize with 
his objurgations against the whole tribe of species makers. 
There is a deal of pseudo science, unripe science—were 
it not undignified I would characterize some of it by an 
expressive monosyllabic word suggesting decomposition 
—published about species by the taxonomists, but I sus- 
pect that there is also a large deal of like obnoxious ma- 
terial lying at the doors of the physiologists and ecolo- 
gists and morphologists. But that fact does not make 
taxonomy or ecology anything less of a science, nor the 
work of able men in either less valuable. I am a little 
weary of hearing from narrow specialists in other depart- 
ments of biology constant condemnation of the taxono- 
mist, and I have been hearing such for the past fifteen 
years from men who should know better. 

Now, as one who has been guilty in the past twenty-five 
years, let me say it humbly, of naming and attempting to 
describe ten or twelve hundred so-called species and gen- 
era, I beg leave to make a few remarks about species. 
You may properly accuse me of being one of those de- 
generates the taxonomists and, as his tribe is not well 
represented here to-night, I may be permitted to present 
his side of the case. I hold no brief for the criminals, 
but, as one of the accused, I would present my own de- 
fense and my own views. 

The question, What is a species? has been asked re- 


186 THE AMERICAN NATURALIST [ Vou. XLII 


peatedly, I may say continuously, since the time of Linné, 
even if our friends the botanists have been somewhat 
somnolent of late. We have had no satisfactory answer, 
for the simple and very good reason that there is none, 
and never will be. If we could go back to the happy 
Cuvierian or even Agassizian days and throw the whole 
responsibility of their definition upon the Creator, seek- 
ing some revelation in Holy Writ, it would save us much 
useless worry. But, as we have long since learned that 
species, like Topsy, just grew, we have and always shall 
have as great difficulty in deciding when varieties and 
races become species as we have in determining when a 
puppy becomes a dog or a lamb a sheep. 

Let me premise further with the statement that ka ue 
taxonomy is the most advanced and difficult of all bio- 
logical science. O modest claim is it not? But I think 
that you will readily admit that evolution, as a science, is 
the highest end of biology—and taxonomy is merely the 
graphical expression of evolution. If, then, we do some- 
times baptize a score of hawthorns, or bedbugs, or coyotes, 
where the breeder or ecologist (hinis that he finds but one 
later, we crave your sympathy and your aid, not your 
scorn ard contumely. The breeder may get all variations 
between the domestic ox and the American bison, and they 
will breed reasonably true by artificial selection, but the 
assertion that Bos americanus and Bos taurus are one and 
the same species would be preposterous. Is it not pos- 
sible that some of our learned breeders of plants and ani- 
mals may be in error themselves in their views of 
‘“species’’? 

All classificatory terms are impossible of exact defini- 
tion. Their use always has and always will depend upon 
the consensus of opinion of those best qualified by wis- 
_ dom, experience and natural good sense. They will never 
become stable; we shall never cease to amend, to change, 
to repudiate old and propose new, because we shall never 
reach the final summation of science. We can only hope 
that all changes shall be for the better, shall be nearer the 


No. 495] WHAT IS A SPECIES? 187 


real truth; that incompetent and inexperienced taxono- 
mists shall be ruled out of court, even as incompetent 
anatomists and cytologists are disbarred. The unfortu- 
nate thing is that we taxonomists have so bound our- 
selves in a snarl of laws and by-laws that we are com- 
pelled to incubate and wet-nurse every premature and 
monstrous taxonomical imbecility till it dies a natural 
death, whereas those of other biologists are promptly 
strangled or thrown out into the cold to die of inanition. 
Let us hope that we may escape from some of that snarl, 
or at least that we may cut some of the bonds which hold 
us too tightly. 

To discuss our subject in all its details and bearings 
and from all view-points would require, not one evening, 
but many. Permit me, therefore, to offer for your con- 
sideration certain axioms of evolution—theories or hy- 
potheses if you prefer to call them such—bearing more or 
less closely upon the question, What is a species? Some 
or all may be familiar to you—I do not know whether all 
have beeen in print ór not—but, such as they are, they are 
all based upon my own observation, and, so far as that 
goes, L am prepared to defend them, and will endeavor to 
do so later if there are any you repudiate, as perhaps 
there are. 

1. The only biological entity is the individual, and the 
individual is inconstant. 

2. The value of specific characters is dependent upon 
a number of interrelated and inseparable factors, the chief 
of which are environment and heredity. 

3. Accumulated heredity may outweigh natural selec- 
tion or environment, and vice versa. 

4. A crescent phylum is more variable, more plastic 
than a long established one; that is, time is always an 
element in the fixation of characters and the limitation of 
variation, and the length of time is dependent more or 
less upon the strenuousness of environment and selection, 
and the plasticity of the type. 

5. New phyla arise from crescent phyla, never from 
decadent or even dominant ones. 


188 THE AMERICAN NATURALIST [ Vou. XLII 


6. The decadent phylum may present as unstable salta- 
tions, generic or even higher characters of allied dominant 
groups; that is a character of generic or even family value 
in a dominant group may be merely an individual varia- 
tion in a decadent one. 

7. The members of a dominant group are, ceteris pari- 
bus, more closely adapted to their environment, their 
characters less variable, their geographical distribution 
more restricted. That is, species of dominant groups 
may be safely based upon less distinctive characters than 
those of a crescent phylum. 

8. It follows that senility and decadence are the at- 
tributes of species, families and orders, as well as of the 
individual. . 

9. The older the genus or allied group of species, the 
more restricted, apparently, is fertile hybridity. For ex- 
ample: The genus Rhinoceros is an old one that has been 
but little modified since early Miocene times; I have never 
learned of cases of hybridity between living species. 
Equus arose in early Pliocene times with all its essential 
modern characters; hybridization between all its living 
species is not difficult, but the hybrids are infertile. The 
genus Bos, while beginning in the Pliocene, did not attain 
full development till Pleistocene times; its numerous spe- 
cies are continuously fertile in all combinations. Rhi- 
noceros is long past the zenith of its evolution; its highest 
specialization was in the Pliocene, or at most Pleistocene. 
Equus, too, is past the highest point of its development, 
perhaps, but not far. Bos, on the other hand, is a domi- 
nant or crescent type; its maximum specialization is in 
the present time. 

10. Secondary sexual characters are transmitted to the 
opposite sex, unless of positive disadvantage. Varietal 
and specific characters, in the natural course of events, 
are more or less unisexual at their inception,-and the con- 
stant tendency is for the characters of one parent to be 
transmitted to offspring of both sexes, even when such 
characters are apparently useless, as seen in the rudi- 


` No. 495] WHAT IS A SPECIES? 189 


mentary mammæ of the human male, which, indeed, some- 
times become of functional use. 

11. Secondary sexual characters are more numerous 
and less stable in the male than in the female; that is, 
female sexual characters, whether primary or secondary, 
may be of generic or even family value in groups wherein 
like characters in the male are merely specific or even in- 
dividual. I am aware that some modern naturalists would 
discredit sexual selection, but, until some hypothesis is 
given to replace it, I must still continue to believe that 
sexual selection is necessary to account for secondary 
sexual characters. 

12. An organ once functionally lost is never perma- 
nently regained by natural selection or any of its hypo- 
thetical substitutes. A hexadactyl species of Homo or 
Felis is impossible. 

13. Giantism in any group is an indication of approach- 
ing decadence; giants never give origin to dominant phyla 
of smaller average size. 

To these I may add, as an article of faith, one more: 

14. Fertility depends chiefly upon the inheritance of 
physiological characters. A modification in the behavior 
of the sperm and germ cells may affect fertility even be- 
fore structural characters have become much affected, 
and vice versa. Human males and females, as we all 
know, are sometimes infertile with each other, though 
each may be entirely fertile with some other; an extension 
of this infertility to races would produce what the tax- 
onomist would accept as species. I furthermore believe 
that the accumulated inheritance of physiological charac- 
ters may and does produce determinate lines of evolution, 
that is, orthogenesis, which may go on into hypergenesis, if 
I may use this term to indicate that hereditary momentum 
which results in over-development of organs. I account 
for this accumulated heredity by the action of past en- 
vironment upon the organism, that is, Lamarckism. I 
am also quite aware that I am with the minority in the 
acceptance of Lamarckism as the chief causative prin- 


190 THE AMERICAN NATURALIST [ Vou. XLII 


ciple of the origin of species. I am told that the direct 
effect of environment in modifying germ characters can 
not be proven, and I retort, neither can it be disproven. 
Paleontologists almost universally, and taxonomists gen- 
erally, are Lamarckians, that is, those who deal chiefly 
with range and distribution, time and space; laboratory 
biologists, on the other hand, are almost invariably op- 
posed to the theory of the transmissibility of acquired 
characters. We can see no alternative hypothesis that 
will meet the requirements of the classificationist or the 
paleontologist, and we respectfully submit that the ex- 
periments of a few years or even scores of years are trivial 
in comparison with the natural experiments that go on 
through tens of thousands of years in the origin and fix- 
ation of species. From my little water-garden some years 
ago I took some plants of the common water hyacinth and 
planted them in the ground. I was surprised to find that 
they grew luxuriantly, but that they did not develop the 
peculiar bladder-like swelling of the leaf stems; when I 
again transferred some small offshoots to the water, they 
promptly redeveloped them. The plants immediately 
changed their structure in adaptation to their terrestrial 
or aquatic environments, and doubtless they would do 
so after many years of isolation. But had the water 
hyacinth been cultivated as a garden plant in the soil 
since the time of Pliny I believe that the terrestrial char- 
acter would have become fixed, and, after all, two or three 
thousand years is a very short time in the history of plant 
species. The Weismannians have «been compelled to 
recede a long way from their first position of the absolute 
and eternal distinction between germ-plasm and body- 
plasm; perhaps we shall yet find an intermediate place 
that will satisfy us all. 

In claiming a high degree of importance for physio- 
logical characters and physiological isolation in the for- 
mation and preservation of species I need not say that 
the term physiological is merely a confession of ignorance. 
All physiological function must inevitably depend ulti- 


No. 495] WHAT IS A SPECIES? 191 


mately upon structure. Two cells absolutely alike must 
doubtless function quite alike. But I doubt if there ever 
are any two cells quite alike. We are already learning, if 
I am correct in my understanding of the claims of Mc- 
Clung and others, that even minor, so-called specific dif- 
ferences are discoverable in the cell, in some groups at 
least. There is, of course, no such thing as a purely phys- 
iological species, for changed structure must underlie all 
variation, though we may not be able to discover the 
differences. I can conceive that additional or modified 
chromosomes in the germ cells of the greyhound might 
indicate a partial physiological isolation which has pre- 
served this race of dogs almost undefiled through more 
than three thousand years; certainly man has not been the 
cause of its preservation. 

Now, if the foregoing theses or hypotheses be true, or 
even if the greater part of them be fundamental principles 
of variation, it follows that the definition of species must 
be made for each and every one that exists or has existed; 
that a specific character in one group may be merely 
varietal in an allied group, on one hand, or generic in 
another, on the other hand. Or, aphoristically, every spe- 
cies, as we know to be the case with every genus, is a law 
unto itself. And this is, practically, the working rule of 
every competent taxonomist, though of course many sad 
errors are made in its application. And it follows that he 
who is best qualified to propose and name species, or to 
eriticize those which have been proposed by others, is one 
whose acquaintance is widest with living forms and with 
the laws which underlie their evolution. He must not con- 
found genetic with adaptive characters, for phylogeny is 
the sole end of taxonomy. : 

Since we can not give an answer to the question, What 
is a species? let us analyze briefly some definitions of 
the past: 

1. A species is a form of life which breeds true to itself. 
The Jewish race has bred true to itself, as indicated by its 
distinctive physiognomy, since the time of Rameses; and 


192 THE AMERICAN NATURALIST [ Vou. XLII 


the Bourbon nose is characteristic of that family. Ergo, 
the Jews and the Bonapartes are distinct species of Homo! 

2. True species are incapable of fertile hybridity. The 
example of the Catalo, the fertile hybrid between Bos 
americanus and Bos taurus, will suffice. The domestic 
dog interbreeds freely on the plains with the coyote, and 
no one doubts the specific validity of Canis latrans, what- 
ever we may think about coyotes in general. The do- 
mestic cat, according to Pocock, is a hybrid between the 
wild cat of England and the wild cat of Egypt, with a 
distinct tendency to vary along ancestral lines after cen- 
turies of fertile hybridity. The domestic races of dog 
freely interbreed, and yet we are quite sure they are the 
derivatives of several wild species of Canis. May not 
fertility, as a physiological inheritance, account for the 
preservation of their distinctive types, notwithstanding 
man’s artificial selection? Is it probable, for instance, 
that the Boston terrier hybrid will continue longer than 
the fad of its breeding remains undiminished? 

3. A species is a type which varies only within narrow 
limits. The jungle fowl is fairly constant in nature. 
Its extraordinary variability is seen in the domestic fowls, 
whether they be derived from a single or several wild 
species. And the doves are still better examples. A 
turkey and guinea-fowl, on the other hand, though they 
have been domesticated for centuries, vary but little from 
their ancestral types. 

There are other definitions. But, you say, if I accept 
no definition of species what rules do the taxonomists 
have who ‘‘make’’ so many thousands of them? We 
must have some, and we do have them, even if we are so 
often accused of depending on whim and imagination. 
And these are mine: Forms of animals which present dis- 
tinct assemblages of characters, in form, color and ar- 
rangements of parts under natural conditions, which are 
recognizable from descriptions and figures, should re- 
ceive distinctive names and be catalogued, provided, of 
course that the assemblage of characters includes all onto- 


No. 495] WHAT IS A SPECIES? 193 


genetic changes. If, in the examination of abundant ma- 
terial from different natural environments, we find these 
characters fairly constant, the forms may properly be 
called species; if not, varieties or races. No perfect spe- 
cific description can be drawn from a single specimen or 
from a few even, and the skill of the taxonomist is con- 
spicuously shown in his ability to distinguish between 
variable and fixed characters, between the essential and 
non-essential, in other words, between old and new char- 
acters. Some taxonomists—and I know such—remain, 
after many years’ experience, unable to dissociate indi- 
vidual from specific or generic characters; they describe 
species as they would describe the physical features of a 
tree or of a rock—and they are the ones who deserve the 
condemnation of other workers. Are such workers con- 
fined exclusively to our branch of biology? 

In nature the interrelated factors, of which environ- 
ment and heredity are the chief, are normally in a state 
of substable equilibrium—variations within given groups 
are within certain fairly definite limits, because the fac- 
tors of variation are. If, however, the cumulation of any 
one factor, either naturally or artificially, occurs, the vari- 
ations become inconstant and the limits of variation are 
changed. The wild pigeon in nature, for instance, is 
governed by fairly constant conditions, and its variations 
are small. Its domestic varieties, were they existent in 
nature, would not interbreed, and would be good species. 
Breeders, I think, lose sight of such things when they say, 
as some do, that they ean produce specific characters, that 
is, characters which are deemed of specific value by tax- 
onomists. They can do nothing of the sort. You may 
break down by changed environments and artificial selec- 
tion what would be real specific characters under natural 
selection and natural environment, but you do not make 
species thereby. Time and fixation by heredity, I believe, 
must always be taken into account in determining varietal, 
specific or generic characters. Mutations of Œnothera 
lamarckiana were found growing wild by de Vries, es- 


194 THE AMERICAN NATURALIST [ Von. XLII 


caped from some garden. Under cultivation he continued 
to breed them, and produced others. But his plants were 
all under abnormal environments. Dr. Lutz, whom we 
all know, is doing some exceedingly interesting experi- 
ments upon certain small flies, Drosophila ampelophila. 
He has produced some remarkable sports or ‘‘muta- 
tions,’’ and the surprising thing is that he finds that such 
sports breed true, that there is an apparent loss of fer- 
tility between them and the normal forms. But I think 
it is absolutely certain—and I speak as an entomologist 
fairly familiar with flies—that it would be impossible to 
produce species of his sports, even though they were bred 
for a thousand years. As some of us know, polydactyl 
eats are rather abundant in some parts of Connecticut, 
breeding true—but who believes in a species of six-toed 
cats? Itis rather unfortunate that breeders confine their 
attention almost exclusively to plastic forms, that is, to 
geologically recent types. Let some one try experiments 
with archaic forms and watch the results. 

Experimental breeding and ecology are the two fields 
of biological research which promise most at present; 
they will doubtless contribute not a little to our knowl- 
edge of the methods of evolution, and correct not a few 
errors in taxonomy; but I say, with full deliberation, that 
experimental breeding without a wide knowledge of tax- 
onomy will lead to false conclusions and be comparatively 
barren of results. The experimentalist, of all men, must 
be well acquainted with varietal specific and generic 
characters in the groups which he studies, or he will be 
working blindly. And I am sorry also to say that some 
of the severest criticisms of taxonomists and Sones, 
have come from some of these men. 


SHORTER ARTICLES AND CORRESPONDENCE 


THE INHERITANCE OF THE MANNER OF CLASPING 
THE HANDS 


Ir the hands be clasped naturally, most people will put the 
same thumb—either that of the right or of the left hand—upper- 
most every time. The position assumed apparently has no rela- 
tion to right- or left-handedness, although, as will be shown, a 
small majority put the right thumb uppermost. Some time ago 
letters were sent out asking for data concerning the manner in 
which the different members of families clasped their hands. 
Among the many generous replies was one from Professor J. 
Arthur Thomson, of Aberdeen, Scotland, giving data for about 
600 individuals. It was intended that the hands should be 
clasped with the fingers of each hand alternating; but this was 
not made as clear as it should have been, and some of the corre- 
spondents clasped their hand with all of the fingers of one hand 
between the thumb and index finger of the other. This con- 
fusion does not exist in Professor Thomson’s data. Accordingly 
only they are discussed in this note. The accompanying table 
gives a condensed analysis of the data, R and L standing for 
right thumb uppermost and left thumb uppermost, respectively. 


Offspring. 
Parents, oan | Ste Female. Total. 
R. i ie A R. beh 
3R. X'OR. 75 71 | 23 | 95 | 40 | 166(725%) | 68 
oR. SOL, 49 | 38 | 22 | 98 | 27 | 61(55.5%) | 49 
3L. X OR. 53 | 46 | 24 | 40 | 40 | 86(57.3%) | 64 
LX OL 36 | 24 22 | 34 | 46(422%) | 63 


It is evident that the mode of clasping the hands is inherited. 
Tt can scarcely be acquired by imitation as it is too slight a thing to 
be noted unless attention is called to it. The thumb position is 
usually quite constant in very young children. However, it 
does not seem to follow the Mendelian law, as neither position 
breeds true. The data show no significant sexual dimorphism, 

195 


196 THE AMERICAN NATURALIST [Vou. XLII 


61 per cent. of the males having the right uppermost and 58 per 
cent. of the females; 59 per cent. of the parents and 60 per cent. 
of the offspring put the right uppermost, so that there does not 
appear to be any reproductive selection. The coefficient of asso- 
ciation between parents of 0.02 demonstrates the lack of assorta- 
tive mating. This last conclusion is in sharp contrast with the 
results concerning other characters in man. 

There are a number of somewhat similar problems in the lower 
animals which are of importance in the study of evolution. Thus, 
the males of the common black cricket (Gryllus) usually keep 
the right tegmen over the left. This results in one set of sound- 
producing organs being functionless. In the closely related 
Locustide there is only one set of sound producing organs and 
the tegminal position is fixed. It would be interesting to know 
if mutations to the other position occur. The fish Anableps anab- 
leps has the anal fin modified into an intromittent organ adapted 
for sidewise motion. On about three fifths of the males it can 
move to the right and on about two fifths to the left. (AMER. 
Nar., xxix, pp. 1012-1014.) A similar state of affairs exists in 
the females, but with the relative frequencies reversed. Copula- 
tion is effected by a right male at the left side of a left female 
and vice versa. Whether the species will eventually split up into 
two on the basis of this character or not would seem to depend 
on how the anal-fin-twist is inherited. However, if the tendency 
to twist to the right or to the left be inherited as a character apart 
from sex there would seem to be no chance of two varieties or 
species being formed, as each mating is between opposites. The 
reversed position of the nerves in the optic chiasma of fishes was 
found by Larrabee (Proc. Am. Acad. Arts and Sciences, xlii, 
No. 12) not to be inherited. 

Frank E. Lurtz. 


NOTES AND LITERATURE 


ICHTHYOLOGY 


Ichthyological Notes——One of the most valuable papers on the 
habits of fishes is a study in sexual selection by Cora D. Reeves, 
‘‘On the Breeding Habits of the Rainbow Darter (Etheostoma 
ceruleum).’?? 

Miss Reeves, a graduate student of Professor Reighard in the 
University of Michigan, has carefully watched the breeding 
habits of this dwarf perch, a species in which the males are 
most brilliantly marked with blue and scarlet. 

It appears that the females do not select the brilliant males, — 
that the oldest and strongest males are most brilliant, that the 
males know the females only by their color, that they mistake 
young uncolored males for females, and that the bright-colored 
males frighten away the younger ones by the display of their 
gaudy fins and by blows of the tail or head. The brilliant 
males were sucessful in pairing in 60 per cent. of the observed 
cases. The sexes as usual in vertebrates are equal in number, and 
the blue and scarlet colors belong to the males alone, these being 
most brilliant at the beginning of the season—about April first. 

These observations give no support to the theory that the 
females choose the gaudy males. It appears however that the 
most brilliant males are the oldest and strongest, and that they 
leave most descendants. This form of the theory of sexual selec- 
tion would seem to be applicable to bright-colored fishes gen- 
erally. 


- Mr. E. W. Gupeer? shows that the hammer-head shark 
(Sphyma zygena) feeds on sting-rays and that the mouth and 
body of the shark are often full of broken-off stings, 50 of these 
being extracted from a single shark 12} feet in length from 
Beaufort harbor. 

Mr. Hersert W. Rano °? discusses the functions of the spiracle 
of the skate, one of these besides the usual function of respira- 
tion is to keep the eyes clean by a jet of water. 

1 Biological Bulletin, XIV, 1907. 

? Science, XXV, p. 1005. 

3 AMER. Nart., XLI, p. 288. 

197 > w 


198 THE AMERICAN NATURALIST [ Vou. XLII 


Mr. CHARLES R. Stockarp‘ describes the development of the 
eggs of the killifish (Fundulus heteroclitus) in a solution of 
magnesium chloride. 

In this fluid the young fishes develop as one-eyed monsters, 
the two eyes coalescing into a single median eye. This eye has 
a single lens. A mixture of sea-water with this solution gives 
the same effect. The influence of the magnesium salt is there- 
fore supposed to cause the strange development of the eyes. 


In the Proceedings of the U. S. Nat. Mus., XXXIII, Jordan 
and Herre describe the cirrhitoid fishes of Japan, describing one 
new genus, Isobuna. 


In the same proceedings, Jordan and Richardson describe a 
new killifish, Lucania browni, from a hot spring in Lower Cali- 
fornia. 


In the same proceedings, Eigenmann & Cole record the species 
of South American Characin fishes in the National Museum and 
in the Museum of Indiana University, with numerous plates 
and descriptions of new species. 


In the same proceedings Professor Edwin Linton describes 
the worms parasitic on fishes of Bermuda. 


In Bureau of Fisheries Document No. 627, Mr. F. M. Cham- 
berlain records his observations on the salmon and trout of 
Alaska. 

Among other matters of interest it is noted that a majority 
of the young red salmon spend their first winter in the lakes, 
while the other species leave early for the sea. It is long known 
that the red salmon never enter a stream that has not a lake 
in its course and that they always spawn in streams above a 
lake. The other four species of Alaska salmon have no special 
relation to lakes. 

Mr. Chamberlain’s observations do not confirm the ‘‘homing 
theory.” Marked salmon fry from the Naha River appeared 
as adults at Yes Bay. Most of the fishes however seem to 
return to the parent stream, from which they probably never 
wander very far. 

Four years is shown to be the usual age of maturity of king 
salmon and red salmon, while the humpback is probably adult 
at an earlier period. 

* Archiv Entwicklungs Mech., XXIII, p. 249. 


No. 495] NOTES AND LITERATURE 199 


Mr. Chamberlain’s paper contains many valuable facts in 
relation to the life of salmon, the fruit of nearly four years 
observation in southern Alaska. 


In the Proceedings of the Biological Society of Washington 
(XX, 1907) Evermann and Goldsborough give a check list of 
the fresh-water fishes of Canada. 145 species are recorded, with 
a complete list of localities. 


In the Proceedings of the same society (XXI, 1908), Dr. 
Evermann describes two new fishes (Fundulus meeki and Salmo 
nelsoni) from streams in lower California. The last-named, an 
isolated troutlet from Mount San Pedro Martir, is especially 
interesting as occurring farther to the southward than any 
other known trout. It is apparently an offshoot of the rain- 
bow trout of California, Salmo irideus. 


In the same Proceedings (XXI, 1908) Jordan and Grinnell 
describe another isolated dwarf waif among the trouts, as 
Salmo evermanni. This troutlet occurs on the headwaters of the 
Santa Ana River, on Mt. San Gorgonio, in San Bernardino Co., 
California. It is shut off from the parent form, Salmo irideus, 
by a waterfall, and in isolation it has undergone considerable 
change. Its origin is parallel with that of the three species 
of golden trout of the high Sierras. Salmo evermanni, living 
on gray granite, is dull in color with none of the scarlet shades 
of the golden trout. 

In the same connection Jordan and Snyder describe and figure 
the great Kamloops trout from Lake Kootenay in British Co- 
lumbia. The specimen figured, sent by John P. Babcock, Fish 
Commissioner of British Columbia, weighed 22 pounds. This 
species is an offshoot of the steelhead trout, Salmo rivularis. 


In the Bulletin of the Bureau of Fisheries, XXV, for 1906 
(October 25, 1907), Jordan and Snyder record a number of 
new species from Hawaii, with several plates, four of them in 
color. The new species are Caraux dasson, Ariommus ever- 
manni, Rooseveltia aloha, Thalassoma neanis and Scaridea aérosa. 

The advent of Japanese fishermen in Hawaii has caused many 
very rare deep-water fishes to be common in the markets; among 
these is the type species, Rooseveltia brighami, of the genus 
named -for the naturalist Theodore Roosevelt. This species, 
scarlet and gold, is one of the most brilliant in Hawaiian waters. 


200 THE AMERICAN NATURALIST [ Vou. XLII 


In the same Bullein, Dr. M. X. Sullivan discusses in detail 
the digestive tract in sharks. 

In the same Bulletin (Vol. XXVI, 1907), Evermann and 
Goldsborough give a catalogue of the Fishes of Alaska, with 
many plates, based primarily on the collections made by the 
Albatross in 1903, under the direction of Jordan and Evermann. 
The following new species are described and figured: 


Polistotrema deani Blennicoltus clarki 
Sebastodes swifti Pholis gilli 

Icelinus burchami Lumpenus longirostris 
Coltus chamberlaini Lycodes jordani 


Many corrections in synonymy are made. One of these the 
present writer does not accept. He believes that the two large 
rays of Monterey Bay, Raja stellulata and Raja rhina, are both 
distinct from Raja binoculata and from each other. The authors 
have overlooked Bryostemma tarsodes described from Alaska by 
Jordan and Snyder. 

This paper is a most useful one to students of Alaskan fishes. 


In the Journal of the Imperial Fisheries Bureau of Japan, 
Dr. K. Kishinouye describes the natural history of the sardine 
of Japan (Sardinella melanosticta) and the related species. 

For some unexplained reason, he unites the Pacific herring 
Clupea pallasi with the Atlantic Clupea harengus. New spe- 
cies of sardine are described under the names of Clupea im- 
maculata, Clupea okinawensis and Clupea mizun. These belong 
to Sardinella, and the last two are from the Riu-Kiu Islands. 
A new anchovy is described as Engraulis koreanus. This 
should belong to the modern genus Anchovia, being very dif- 
ferent from Engraulis japonicus. 

In the Journal of the College of Science, of the Imperial 
University of Tokyo (XXI, 1907), Professor S. Hatta of Sap- 
poro describes the gastrulation of the embryo of the lamprey. 

In the Proc. Zool. Soc., London (1906), Professor Bashford 
Dean has notes on living specimens of the Australian lung-fish 
(Neoceratodus forsteri). Its movements are notably those of an 
amphibian rather than a fish. 

In the Annals of the Museum of Natal, Mr. C. Tate Regan 
deseribes new species from that coast. A species of remarkable 
interest is a new saw-shark, Pliotrema warreni, with six gill-slits. 


No. 495] NOTES AND LITERATURE 201 


In the Annals of the Museum of Vienna, XXI, 1906, Dr. 
Viktor Pietschmann has a valuable record of the fishes collected 
in a voyage to Iceland, and another to Morocco. 


In Records of the Australian Museum, VI, 1907, Allan R. 
McCulloch describes the fishes and crustaceans taken by the 
oy Woy, in deep waters of the Tasman Sea. The most notable 
of the new species is the sculpin-like fish, Hoplichthys haswelli. 


In the Journal of the Linnean Society of London, Mr. A. D. 
Darbishire describes the water current in the spiracle of sharks. 


In the Sitzber. of the same museum, Vienna, Vol. 116, 1907, 
Dr. Viktor Pietschmann describes new sharks from Japan, Cen- 
trophorus steindachneri and Etmopterus frontimaculatus. 

The last species was also taken by Jordan and Snyder in 
Sagami Bay, in company with Etmopterus lucifer. It is one 
of the smallest of sharks, black, with a milk-white spot on the 
top of the head. 


In the Proc. Zool. Soc., London (1907), Mr. Regan redescribes 
Velifer hypselopterus, a Japanese species not seen in the last 
fifty years, from three specimens in the British Museum. A 
second species from northern Australia is described as Velifer 
multiradiatus. 

In another paper Mr. Regan brings together the aberrant 
genera Lampris, Velifer, Trachypterus and Lophotes, framing- 
of these a new suborder Allotriognathi. These fishes, like the 
Berycoids have an orbitosphenoid, but no mesocoracoid bone. 

Mr. Regan thinks that these fishes are derived from the bery- 
coids, and the latter from forms like the extinct Ctenothrissa and 
Pseudoberyx. These observations of Mr. Regan are very inter- 
esting and his conclusions seem reasonable. He notes that 
Semiophorus is allied to Platax and not to Lampris. 

In ‘‘ Wissenschaftliche Ergebnisse einer Zoologischen Expedi- 
tion nach dem Baikal-See’’ (1907), Dr. Leo Berg discusses the 
sculpin-like fishes of Lake Baikal, the Cottide, Cottocomephoride 
and Comephoride. The excellent monograph is preceded by a 
careful account, fortunately in German not Russian, of the 
osteology of these fishes. Of the 34 species of fishes found in 
Lake Baikal 17 are endemic, or developed in the lake, not occur- 
ring elsewhere. Of these, two genera, Comephorus and Cotto- 
comephorus, each constitutes a distinct family. Other genera 


202 THE AMERICAN NATURALIST [ Vou. XLII 


peculiar to this lake are Abyssocottus, Cottinella, Limnocottus, 
Procottus, Batrachocottus and Asprocottus. The fauna de- 
scribed in this paper is one of peculiar interest. 


In another paper in the Annuaire de l’Académie de St. 
Petersbourg, XI, 1906—unfortunately entirely in Russian—Mr. 
Berg discusses the Old World species of minnows of the genus 
Phoxinus. 


_ In the same Annuaire, vol. XII, 1907, Mr. Berg treats in 
Russian and in English, the fresh-water fishes of Corea. The 
genus Longurio of Jordan and Starks is united by Berg to 
Saurogobio of Bleeker, and Fusania with Aphyocypris of Günther. 
In another paper Mr. Berg discusses Siberian species of Rhodeus. 


In the ‘‘Fauna America-Centrali’’ Mr. C. T. Regan continues 
his account of the fishes of Mexico and Central America. Ami- 
urus meeki is described from Chihuahua, Moxostoma mascote 
from Jalisco, Algansea affinis from Rio Lerma, Algansea stigma- 
tura from Rio Grande de Santiago. Several species recognized 
by other authors are placed in synonymy. In some cases this 
process exchanges one doubtful opinion for another. 


In Popular Science Monthly, LXXI, January, 1908, Dr. 
Jordan describes ‘‘The Grayling at Caribou Crossing,’’ a run- 
ning descriptive account of the Yukon country, with a dash of 
angling. 

In Science, XXVI, 1907, Dr. Bashford Dean reviews Dr. 
Eastman’s recent papers on the ‘‘Kinship of the Arthrodires,’’ 
Dr. Eastman claims that these mailed fishes are Dipnoans and 
to this conclusion Dr. Dean enters a ‘‘friendly protest.’’ 


In the American Journal of Anatomy, VII, 1907, Dr. Dean 
discusses the structure and origin of the Acanthodian sharks, 
one of the most primitive of the extinct forms. Their relation- 
ships are with Cladoselache, a form having fins of the fin-fold 
type, and probably the most primitive of known sharks. 


In Archives de Zoologie Experimentale, VII, 1907, Dr. Louis 
Fage describes the fishes of the Balearic Islands, with several 
new species. The paper can be especially praised for its atten- 
tion to laws of nomenclature, as also for the accuracy and full- 
ness of its accounts of the new forms. Two species are referred 
to the genus Eleotris, a group not hitherto recorded from 

Europe. Neither of the species, however, belongs to Eleotris 


No. 495] NOTES AND LITERATURE 203 


proper. Eleotris pruvoti is an ally of Valenciennea and Eleotris 
balearica approaches Gymneleotris. 

Dr. JACQUES PELLEGRIN publishes in the ‘‘Mission Scien- 
tifique,’’ 1907, an account of the fishes of the high mountain 
lakes of South America. 

In a weekly Journal, the Sydney Mail, Mr. Charles Thackeray 
gives a readable and accurate account of the game fishes of 
New South Wales, with wood cuts of the leading species. 


ECHINODERMATA 

The Stalked Crinoids of the Siboga Expedition..—There has 
recently been published a monograph on the recent stalked 
crinoids of the East Indies, based on collections made by the 
Siboga which is the first important contribution to our knowl- 
edge of the group since the publication of Dr. P. Herbert Car- 
penter’s great work (the Challenger report) in 1884. 

The first thing to attract the attention of the student of the 
recent crinoids is the announcement of the discovery of the infra- 
basals in a species of Metacrinus, M. acutus, a new species here 
first described. Dr. Carpenter stoutly maintained that infra- 
basals did not occur in any species of recent crinoid, and he 
criticized rather sharply the so-called law of Wachsmuth and 
Springer, by the application of which the recent genera Iso- 
erinus and Metacrinus were shown to be dicyeclic. He dissected 
numerous specimens of various species of both genera, and ac- 
cording to his statements and figures, appeared to conclusively 
prove their absence. In 1894 the Swiss paleontologist de Loriol 
discovered and figured infrabasals in a fossil species of Isocrinus, 
and now Professor Déderlein shows their presence in Metacrinus. 
This discovery by Dr. Döderlein was made simultaneously by the 
present reviewer in two other species of Metacrinus and in Iso- 
crinus decorus and announced in a paper now in press, which 
had gone through the final proof before Dr. Déderlein’s contribu- 
tion was received. In this the infrabasals of Metacrinus rotundus 
from Japan and of M. superbus from the China Sea, and of Iso- 
crinus decorus from Cuba are described and figured. 

1 Die Gestielten Crinoiden der | Siboga-expedition | von | L. Döderlein. | 
Monographie XLIIa aus | Uitkomsten op Zoologisch, | Botanisch, Oceano- 

hisch en Geologisch gebied | verzameld in Nederlandsch Oost-Indië 
1899-1900 | aan boord H. M. Siboga onder commando van | Luitenant ter 
zee 1° KI. G. F. Tydeman | uitgegeven door | Dr. Max Weber. 


204 THE AMERICAN NATURALIST [Vou. XLII 


The Siboga dredged stalked crinoids at seventeen stations, in 
all more than sixty specimens representing thirteen species and 
two additional varieties. Three of these species are referred to 
Bathycrinus, one to Rhizocrinus, two to Isocrinus, and the re- 
mainder to Metacrinus, while the species of Rhizocrinus dredged 
by the Valdivia off Somaliland and recorded by Chun in 1900 is 
included in the report, and figured under the name of R. chuni. 

. The species referred to the first two genera are of very excep- 

tional interest, apart from the fact that neither genus has been 
recorded from the East Indian region; while the Rhizocrinus 
(R. weberi n. sp.) is related to R. rawsonii of the tropical At- 
lantic, the three Bathycrinus are in their characters quite unlike 
anything previously known; in the first place, they are all very 
small, one species, B. poculum, being only 8 mm. in total length, 
while none of the others exceeds 35 mm.; but, most remarkable 
of all, they unite the characters of Bathycrinus and Rhizocrinus 
so completely as to leave scarcely any grounds for considering 
them as distinct genera. This discovery was not news to the 
present reviewer; for the day after the receipt of Dr. Déderlein’s 
work, his own description of two intermediate species, Bathy- 
crinus equatorialis and B. caribbeus was published. Rhizocrinus 
(ineluding, as we now apparently must, Bathyerinus) contains 
at the present writing fifteen described species, of which nine 
have been made known during the past year, and there are sev- 
eral additional species now in press; it is very evident that our 
knowledge of even this comparatively old genus is still extremely 
rudimentary. Dr. Déderlein’s interesting remarks on the shed- 
ding of the arms in Rhizocrinus—Bathyecrinus I shall consider 
in detail later. 

Isocrinus naresianus, first found by the Challenger, was redis- 
covered by the Siboga off the northern end of Celebes, having 
been previously known only from the Kermadee and the Meangis 
Islands, and from Fiji, and a new species, I. sibogæ, was dis- 
covered near Timor. This last belongs to the group of the genus 
in which the costals and division series consist of two joints, 
bound by syzygy, including such species as I. wyville-thomsoni, 
I. parre (of Guérin 1835 — I. miilleri of Oersted 1856 of which 
I. maclearanus is merely a variety) and I. alternicirrus, to the 
last of which J. siboge is most nearly related, though it possesses 
the normal arrangement of the cirri. The form maclearanus, by 
the way, did not come from the southwest Atlantic as stated by 


No. 495] NOTES AND LITERATURE 205 


Dr. Déderlein, but from the west central Atlantic; moreover, it 
was first described by Wyville Thomson, and not by Carpenter; 
also I. wyville-thomsoni was first described by Wyville-Thomson, 
Jeffries’s mention of the name being in both cases a pure 
nomen nudum. 

The discussion of Metacrinus is appropriately begun with an 
account of the infrabasals of M. acutus, which are compared to 
those of Millericrinus polydactylus. Then follow paragraphs on 
the specific characters of the genus found in the calyx, the arms, 
and the stem, which last is believed to furnish the most reliable 
characters. In this conclusion I heartily concur. The stems are 
considered at some length, and there is an interesting account of 
the stem growth, a subject which I shall discuss at some length 
later. Dr. Döderlein believes that, when living on the sea- 
bottom, the species of Metacrinus have very long stems, which are 
inextricably entangled one with another, forming a sort of mesh- 
work, from which the younger part of the stem and the crowns 
stand out; in other words, that the individuals form a sort of 
erinoid colony, the crowns arising from a maze of stems, and he 
adduces considerable strong evidence in support of this view. It 
will interest him to know that I have additional evidence pointing 
to the same conclusion. 

The species of Metacrinus obtained by the Siboga all fall into 
that division of the genus in which there are ‘‘five radials,’’ 
two of which are united by syzygy; three new species, M. acutus, 
M. serratus and M. suluensis, and a new variety, M. nobilis 
timorensis, are described, while that somewhat unhappy word 
typica is used'to denote the typical forms of M. nobilis and M. 
superbus. M. acutus comes from the Ki Islands, and M. serratus 
and M. suluensis were found in the Sulu Archipelago. M. nobilis 
timorensis, as its name indicates, occurs near Timor. M. cingu- 
latus, previously known from the Ki Islands and the Arafura 
Sea, was rediscovered at the Ki Islands and at Timor; M. vari- 
ans, from the Kermadee and Meangis Islands, was found 
at Timor, the Ki Islands, and in the Sulu Archipelago; 
and a varietal (unnamed) form of M. superbus was col- 
lected at the Ki Islands. Metacrinus nobilis is divided into 
three varieties, typica, murrayi and timorensis, with somewhat 
unfortunate nomenclatorial results; for the specific name murrayi 
of Carpenter has precedence over nobilis of the same author. 
Expressing these names as trinomials, we have Metacrinus mur- 


206 THE AMERICAN NATURALIST [ Vou. XLII 


rayi murrayi, M. murrayi typica, and M. murrayi timorensis, 
the typica not representing the typical form at all. Metacrinus 
murrayi (to speak with nomenclatorial accuracy), previously 
known from the Ki Islands and Arafura Sea, was again found 
at the Ki Islands, and also at Timor. 

Perhaps it is wisest to do as Dr. Döderlein has done and recog- 
nize by name the various geographical variations of the Meta- 
crinus species, but it certainly conjures up a terrible vista of 
possibilities, for it is difficult to imagine more variable organisms 
than the species of this genus, according to my experience. I 
have examined some additional varieties of M. superbus from 
Japan, and a bewildering, though small, series of M. angulatus 
from the same locality, some of which fall into the group with 
‘five radials,” and others into that with eight to twelve, while 
M. rotundus, also falling into both groups, is even more variable; 
and it seems to me that if we once get a good start on the tri- 
nomial system in any branch of the recent crinoidea, with the 
continuance of the present activity in the field, it will not be 
long before each genus will require a specialist for its elucidation. 

Dr. Döderlein is to be congratulated on the results of his 
study of the Siboga collection, and the production of a vol- 
ume which will long stand as the authoritative work on the 
stalked crinoids of the East Indian seas, and which not only 
treats of the stalked crinoids systematically as a class, but sug- 
gests many interesting new lines of investigation, and bears 
throughout the stamp of one who not only has an exhaustive 
knowledge of the group under consideration, but of many differ- 
ent forms of animal life as well. 


AUSTIN HOBART CLARK. 
U. S. BUREAU OF FISHERIES.? 


ANIMAL PATHOLOGY 


Trypanosome Diseases.—Recent investigations which have been 
earried out in foreign laboratories with the object of ascer- 
taining the mode of cure for sleeping sickness, and other try- 
panosome diseases have resulted in demonstrating certain fea- 
tures in the biological conduct of these protozoa towards chemical 
stimuli which are of extreme interest. Thus far only three 

2 Published with the permission of the Commissioner of Fish and 


No. 495] NOTES AND LITERATURE 207 


groups of chemicals have been discovered which are efficient in 
the treatment of trypanosome infections. They are: (a) benzi- 
din dyes, (b) basic triphenyl-methane dyes and (c) arsenical 
compounds. In experimental animals complete cure has appar- 
ently been effected by maximum doses of these compounds. With 
lesser doses and prolonged treatment the parasites may disappear 
from the blood for a time, but later on make their appearance 
again. Those which recur have undergone a pronounced change 
in their biological characters and constitute a strain resistant to 
the therapeutic agent employed. Such a strain manifests chemo- 
resistance of a specific character towards the particular sub- 
stance used to develop it and an increased resistance towards 
other compounds of the same group. On the other hand, the 
development of resistance towards one group causes no increase 
whatever in the resistance towards other groups. By continued 
experiments, however, a strain has been produced manifesting a 
triple resistance, specific towards each of substances employed. 

Chemo-resistance, once acquired, persists unchanged while the 
resistant trypanosomes are passed through normal animals even 
for one hundred and forty transfers extending over fourteen 
months. This has been cited as strong evidence of the trans- 
mission of acquired characters. The specificity of the resistance 
is very striking. After an experimental animal has been inocu- 
lated with a mixture of two resistant strains and is then treated 
with a substance towards which one of the elements is resistant, 
the other element will disappear from the blood, but the resistant 
strain will remain and develop unchecked. Indeed, the two 
strains remain separate and capable of isolation after repeated 
passages through infected animals. Or, in other words, a strain 
with double resistance or with modified resistance does not arise 
as the result of infection with a mixture of two resistant strains. 

Henry B. Warp. 


ANIMAL BEHAVIOR 


Recent Work on the Behavior of Higher Animals.—There exist 
to-day two main centers for the strictly scientific and experi- 
mental study of the behavior of the higher animals. One is 
at Harvard, led by Yerkes, the other at Chicago, under Watson. 
Excellent work appears at times from other quarters, but it can 
usually be traced to the influence of one of the two men named. 
There is a third independent center for such work at Clark 


a 


208 THE AMERICAN NATURALIST [ Vou. XLII 


University, but lacking the single-minded leadership of the other 
two, the attack on the problems has there been less unified and 
effective. Thorndike, whose work some years ago gave such 
impetus to the whole subject, has unfortunately been drawn into 
other work, or we should doubtless have another most effective 
center for such investigations. Outside of the United States 
the scientific study of the behavior of the higher animals is a 
negligible quantity, compared with what comes from the centers 
named. The active French movement in comparative psy- 
chology, under the influence of Bohn, Piéron and others, has 
been thus far limited mainly to the invertebrates. 

At the laboratories we have named the work on animals is 
carried on by the aid of such accurate appliances and methods 
as have long been developed for the investigation of the physio- 
logical psychology of man, with ingenious modifications and ad- 
ditions as required by the peculiarities of the subject. This 
gives the work an almost uniquely precise and scientific char- 
acter, as compared with most other studies in animal behavior. 
Most other workers have been compelled to content themselves 
with apparatus, observations and experiments of a more ‘‘home- 
made’’ character. The two leaders, one by training a zoologist 
and psychologist, the other a physiologist and psychologist, have 
been devoting themselves largely to rats and mice of late, while 
followers have made side excursions into the territory of cats, 
dogs and raccoons. It is necessary to concentrate the attack 
somewhere, and for the present the rats and mice are bearing the 
brunt. We shall pass in review the recent contributions from 
the centers named, limiting ourselves at present to work in- 
fluenced from Harvard. 

From Harvard we have first the elaborate study of the dan- 
cing mouse, by Dr. Yerkes.t Perhaps the most striking feature 
of this work lies in the elegant and fertile methods devised by 
the author, and of course in the results attained by these 
methods. The main method consists in a sort of ‘‘Lady or the 
Tiger’’ alternative presented to the unsuspecting mouse. He 
is invited to enter one of two doors; one leads to an electric 


‘shock, the other to freedom and food. The fateful portals are 


marked with signs of various sorts,—cards of different shapes, 
markings, color, brightness, odor, ete. The ‘‘right’’ and ‘‘wrong’’ 
doors can be alternated at the will of the experimenter, as can 

1 Yerkes, R. M. The Dancing Mouse, a Study in Animal Behavior. 
The Animal Behavior Series, Vol. I, 290 pages. The Macmillan Co., 1907. 


No. 495] NOTES AND LITERATURE 209 


the signs. The mouse in repeated experiments tries at first the 
simple plan of returning to the right or left door according 
as he has found that to be correct. When he finds that the 
correct portal is being alternated, he quickly learns to alternate 
in his choices. But when he finds that there is no regularity in 
the alternations, he begins to pay careful attention to the signs 
posted about the portal; ‘‘to run from one to the other, poking 
its head into each and peering about cautiously, touching the 
eardboards at the entrances, apparently smelling of them, and 
in every way attempting to determine which box could be 
entered safely.’’ Often the mouse runs from one portal to the 
other twenty times or more, before deciding which to enter. | 
Now, it is in this state of uncertainty and concern that the 
mouse is ready to give interesting results in animal education 
and in sense physiology. He uses all his senses to the best of 
his ability in determining which is the ‘‘right’’ door to enter, 
so there is opportunity, which Dr. Yerkes has skilfully used, 
to test his senses, and at the same time to study his ability to 
learn. When the two portals are indicated, the ‘‘right’’ one 
by a light card, the ‘‘wrong’’ one by a dark card, the mouse 
learns to choose the correct card. If for both cards are substi- 
tuted others that are of deeper shade, but have a similar relative 
brightness, the mouse continues to choose the one of lighter 
shade. He has learned, not that a particular card, or a partic- 
ular shade, is the right one, but that the lighter of the two is the 
one to choose; he often runs back and forth many times, seeming 
to compare them carefully. By accurately grading the difference 
in brightness between the two portals, it was possible to deter- 
mine just what differences the mice could discriminate, giving 
an opportunity for work on Weber’s law. The mice rapidly 
learned to discriminate finer and finer shades of difference. A 
certain mouse, in a first series of experiments, could discriminate 
only when the difference in brightness was practically half the 
greater brightness. In a later series he could discriminate when 
the difference was but one fifth and, after much more practise, 
when the difference was only one tenth. Such edueability at 
first carried confusion into the data designed to test Weber’s’ 
law. When it was finally taken into account, the law was found 
to hold. 

In a similar way Yerkes made extensive studies of color vision 
in the mouse. He found that apparently they do not see colors, 


210 THE AMERICAN NATURALIST [ Vou. XLII 


at least not as we do; that most of their apparent discrimina- 
tion of color is due to differences in brightness; and that the 
brightness of different colors is not the same for them as for 
ourselves. 

It is extraordinary that the mice were unable to discriminate 
the portals by different shapes of cards or of lights. They 
showed no power of distinguishing forms. 

We have given some samples of Yerkes’ methods and results; 
many other matters of equal or greater interest were studied, 
by varied methods, including the classic one of using labyrinths. 
The author’s experiences are set forth in interesting chapters 
on educability, methods of learning, the efficiency of different 
methods of training, the duration of habits, the revival of lost 
habits, individual differences in behavior, and the like. When 
it comes to responding to experimentation, the dancing mouse 
is, as its name indicates, rather an artistic than a strictly utili- 
tarian animal, giving a delightful variation from those orthodox 
creatures whose main desire is to ‘‘get there,’’ so that results 
are not readily expressed correctly in terms of minutes required 
and space passed over. ‘‘Most mammals which have been 
experimentally studied have proved their eagerness and ability 
to learn the shortest, quickest, and simplest route to food with- 
out the additional spur of punishment for wandering. With 
the dancer it is different. It is content to be moving; whether 
the movement carries it directly to the food-box is of secondary 
importance. On its way to the food-box, no matter whether the 
box be slightly or strikingly different from its companion box, 
the dancer may go by way of the wrong box, may take a few 
turns, cut some figure-eights, or even spin like a top for a few 
seconds almost within vibrissa-reach of the food-box, and all 
this even though it be very hungry.” 

In addition to the strictly experimental work, Yerkes gives 
a full account of the peculiar ‘‘dancing’’ movements that have 
given the animal its name; a sketch of what we know of its 
history, and an extensive discussion of the disputed question 
as to whether its ears are defective and whether it is deaf. 
Yerkes concludes that it can hear only for a few days, when 
about two weeks old. 

Altogether, Dr. Yerkes’ book is one of the most attractive 
as well as one of the most valuable of the strictly scientific 
studies of animal behavior. It would be venturing out of the 


No. 495] NOTES AND LITERATURE 211 


‘*strictly scientific,” but one wishes that the author might give 
us an imaginative picture of what life and the universe may be 
in the consciousness of this little creature, that does not hear, 
sees little or nothing of colors, can’t distinguish a square box 
from a round one nor a circular card from a triangular one, 
feels impelled to ‘‘cut figure eights and spin like a top’’ on its 
way to a dish of food, and learns many things rapidly and 
well. Possibly such an unscientific picture could be appended 
to the really scientific account without injury to the latter! 
Dr. Yerkes is still studying the dancing mouse, and may some 
time feel prepared to give us such a picture. 

Or perhaps we must look for such pictures to the second 
volume of the Animal Behavior Series, of which this is the 
first! The second one, just announced, is a volume on ‘‘The 
Animal Mind,’’ by Margaret Washburn. The Series, edited 
by Dr. Yerkes, promises to be of the greatest value. 

A matter that has been most in need of study is the part 
played by imitation in the behavior of higher animals. Years 
ago imitation was the favorite refuge of those who wished to 
explain the remarkable actions of animals without attributing 
to them higher intellectual powers. When Tabby pressed the 
latch and walked out the door, that was because she had seen 
some one do it. Then came Thorndike, and changed all that. 
To give imitation in place of reason as an explanation, says 
Thorndike, is to substitute one false explanation for another. 
In studying cats and monkeys, Thorndike saw no signs of imita- 
tion either of one another or of man. And most later investiga- 
tors have agreed that imitation plays little part in the behavior 
of animals, at least in comparison with what had been supposed. 
Even the monkey, we are told, rarely imitates man or other 
monkeys. Direct, unrefilective imitation of simple sounds or 
movements—the performance of an act merely because a com- 
panion has performed it, without reference to results—is less 
rare, though likewise not so common, as had been supposed. But 
the imitation of an act because that act accomplished a certain 
result, and in order to accomplish the same result—this was 
not found, though this is the kind of imitation assumed in cur- 
rent explanations to be common. The extensive experiments of 
Hobhouse,? evidently undertaken with the expectation of find- 
ing imitation playing a part, are striking as an example of how 

? Mind in Evolution, Chapter VIII. 


212 THE AMERICAN NATURALIST [ Vou. XLII 


little it is possible to find, and how uncertain is what is found, 
even with the best of will. Kinnaman, Small and others had 
incidentally seen a few examples of real imitation. We have 
now from the Harvard laboratory two careful studies of this 
matter by Berry,*® with results that are most interesting. In 
Berry’s rats and cats we find imitation as it were in the making. 
Our conception of imitation, and of its different kinds, loses its 
sharp lines and angles and becomes indefinite. When one knows 
how to escape or get food and another does not, the animals 
do not set to work to imitate each other’s actions in the clear- 
cut way we are apt to think of as imitation. But the one that 
doesn’t “‘know how’’ does after some time begin to pay atten- 
tion to his comrade’s actions, and then in an indefinite way to 
do something of the same sort himself. ‘‘We found that when 
two rats were put into the box together, one rat being trained 
to get out of the box, and the other untrained, at first they were 
indifferent to each other’s presence, but as the untrained rat 
observed that the other was able to get out, while he was not, 
a gradual change took place. The untrained rat began to watch 
the other’s movements closely; he followed him all about the 
cage, standing up on his hind legs beside him at the string, 
and pulling it after he had pulled it, ete. We also saw that 
when he was put back the immediate vicinity of the loop was 
the point of greatest interest for him, and that he tried to get 
out by working at the spot where he had seen the trained rat 
try.’’* In cats similar and more marked eases of imitation 
were found and analyzed. 

Berry’s work is the first really scientific study of imitation in 
animals that we have had, and it shows, as so commonly happens 
when a thorough study is made, that we can not make extreme 
statements, whether positive or negative. Imitation is found; 
even ‘‘reflective imitation,’’ but it is not precise; we can often 
hardly be certain whether it is imitation; and where it is 
more pronounced it is difficult to distinguish imitation for the 
mere sake of doing what a companion does, from imitation for 
the purpose of accomplishing the result that the companion 
accomplishes. Like all other traits of behavior, imitation grows 
gradually out of something that seems not the same thing at 

* Berry, C. S. The Imitative Tendency of White Rats. Journ. Comp. 
Neurol. and Psychol., 16, 333-361. Id., An Experimental Study of Imita- 
tion in Cats. Ibid., 18, 1908, pp. 1-25. 

t Berry, The Taitative r d of White Rats, p. 358. 


No. 495] NOTES AND LITERATURE 213 


all! Whether to call this ‘‘something’’ by the same name as 
the developed activity is one of the frequent grounds for un- 
profitable controversy. 

L. W. Cole® has made an elaborate investigation of the in- 
telligence of raccoons, with results of more than usual interest. 
The raccoons are compared throughout with the famous cats of 
Thorndike, and the work, like most recent work on animal in- 
telligence, follows the outlines of the well known paper of the 
author just mentioned. But Cole has made real and impor- 
tant advances in both method and results. The raccoons are 
either much more clever than the cats, or the methods employed 
were better fitted for bringing out latent possibilities; probably 
both these things are true. The experiments consisted largely 
in allowing the animals to learn to open boxes closed by fasten- 
ings of various degrees of complication. The raccoons learned 
somewhat more readily than the eats. As in all other animals, 
their learning was largely by trial and error. But they are 
not restricted exclusively to that method, as Thorndike main- 
tained to be the ease for the cats; decidedly not if we limit that 
method to the gradual formation of an association between a 
motor impulse and a sense perception. (1) There was clear 
evidence that the animal at times, catches the idea, that a certain 
act is what opens the door, so that he later acts directly and at 
once on that idea. It is not a mere gradual exclusion of useless 
movements, till only the useful ones are left. (2) The raccoon 
learns by being put through an act. It learns without ‘‘in- 
nervating its muscles,’’ the great test for the possibility of learn- 
ing in Thorndike’s eats. It learns to go into a box by a certain 
entrance, through having been lifted into the box that way a 
number of times. By being put through them, it learns certain 
acts which it was unable to learn by its own efforts. By putting 
different raccoons through the same act in different ways, they 
learned to perform it in different ways; for example, one peren 
to lift a latch with its paws, another with its nose. (3) Wh 
the raccoons, like most other animals, do not imitate each stain 
or any one else in a marked degree, they did, after seeing the 
experimenter perform a certain action many times, ‘‘catch the 
idea” and endeavor to perform the action for themselves. This 

5 Cole, L. W. Concerning the Intelligence of Raccoons. Journ. Comp. 
Neurol. and Psychol., 17, 1907, pp. 211-261. 

* Thorndike, E. L. Animal Intelligence. Psychol. Review, Monograph 
Suppl., vol. 2, 1898. 


214 THE AMERICAN NATURALIST [ Vou. XLII 


is of course the essence of ‘‘reflective’’ imitation. (4) Thorn- 
dike concluded that cats have probably no ‘‘free ideas’’; no 
stock of images which are motives for acts. The association in 
the cats was always between a motor impulse and a present 
sense perception; there was no association of ideas. This nega- 
tive conclusion was based largely on the inability of the animals 
to learn from being put through an act. In this latter matter, 
Cole calls the reader’s attention particularly to ‘‘the radical 
difference at every point’’ between the eats of Thornidike’s 
experiments and the raccoons of his own. ‘‘If inability thus 
to learn is evidence against the presence of ideas, then ability 
to do so should be equally strong evidence for it.’? Further- 
more, Cole gives much additional evidence for the presence of 
ideas in the raccoons; and certain results of some extremely 
ingenious experiments amount to a demonstration that the ani- 
mals do hold mental images, so far as such a thing can be 
demonstrated.” The animals seemed to remember definite ob- 
jects for a time, then forget them; then suddenly, under certain 
conditions, recall them. They fought against being put into 
boxes with complex fastenings, from which they had some time 
before had difficulty in escaping, though they willingly went into 
similar boxes whose fastenings they had found simple. In cer- 
tain experiments there were two alternative signs to be raised; 
the green one meant food, the red one meant none. The raccoons 
learned to raise these signs by clawing at the standards, but they 
could not see beforehand which sign would come up by claw- 
ing at a certain standard. When the red one came up they 
clawed it down again, then clawed up the green one, and made 
ready to receive food. Clearly, the red sign did not correspond 
to an image that the animal had in mind, while the green one did. 
Other experiments were devised in which success depended on 
the animal’s holding in mind the images of certain things that 
had gone before; the raccoons stood these tests successfully. It 
is difficult to see how there could be more conclusive proof of 
the presence of ideas in animals that can not talk. 

7 A subjective thing, such as an idea, can, of course, not be absolutely 
demonstrated by objective methods. It is always possible to substi- 
tute for the idea its physiological accompaniment, and say that this is 
all that we can be assured of. In other words, ‘‘demonstration of the 
existence of ideas’’ in animals can never go further than to show that 
they act as men do when men have ideas. 


No. 495] NOTES AND LITERATURE 215 


The interesting paper of Hamilton® is perhaps in its origin 
independent of the Harvard laboratory. We have seen that the 
dancing mouse learns to act on the basis of a comparison be- 
tween two things, selecting, not a particular thing, but the 
lighter of two, or the darker of two, ete. Kinnaman found 
that the monkey could similarly learn to choose always the 
lighter vessel, or to choose the colored vessel from among a num- 
ber of vessels, even when the colors were changed. Hamilton 
made a precise study of a similar sort of action in a dog. The 
animal learned that in order to escape from a pen and get 
food he must press, out of a number of levers, the one that 
bore the same sign that was found on a general sign-board 
elsewhere in the pen. In successful cases his method of pro- 
cedure was, then, to inspect the general signboard, then to pass 
in review the four levers till he found the one that bore the 
same sign—then to press this. This appears to involve a fairly 
complex mental operation (if we may venture to interpret the 
actions of animals from that highly reprehensible standpoint). 
The dog clearly learned to choose in the way described. But 
unfortunately, being a clever dog, he after a time discovered 
a much simpler method of action that accomplished the same 
results. He merely began at one end of the series and pressed 
the levers in order till he came to the one that worked. When 
electric shocks were attached to the ‘‘wrong’’ levers, he de- 
cided that he didn’t care to play at that game any longer, and 
the experiments had to end. 

How far such action, seeming to involve complex mental 
operations, may be demonstrated in animals when there has 
been fifty years’ development of method and results in such 
investigations, instead of merely two or three attempts at it, 
is a question that deserves consideration by those who are so 
ready to deny, on the basis of what we now know (or rather, 
on the basis of what we don’t know), all mental complexity 
in animals. 

Indeed, it is clear that much of the work we have just reviewed 
consists in showing experimentally that the mental operations 
of animals are more complex than had been supposed; in re- 
storing to animals certain things that had been denied them. 
And this is typical. The recent history of the study of animal 

*Hamilton, G. van T. An Experimental Study of an Unusual Type 
of Reaction in a Dog. Journ. Comp. Neurol. and Psychol., 17, 1907, pp. 
329-341. 


216 THE AMERICAN NATURALIST [ Vou. XLII 


behavior has shown a curious parallelism in each of its three 
great divisions. In each division the slate was, as it were, wiped 
clean some ten or fifteen years ago; the existing structure was 
razed to the ground, and we have been building it up again 
ever since. In the lower organisms Loeb reduced the phe- 
nomena to almost inorganic simplicity. For the ants, bees and 
other higher invertebrates Bethe took similar action; they were 
stripped of their fanciful decorations of memory, intelligence, 
etc., and left absolutely devoid of ‘‘psychie qualities’ of any 
sort; their behavior was composed of invariable reflexes and 
tropisms of the simplest character. Thorndike performed the 
same operation for the vertebrates. Not only did they not 
reason (preposterous notion!), but they did not imitate, could 
not learn by seeing a thing done nor by being put through 
an act, nor by any other way than by simply gradually drop- 
ping out useless movements from among those made at random; 
and they had not even ideas of things past, to say nothing of 
perceiving relations or being capable of trains of thought or 
of formulating a plan. : 

In all three divisions of the subject the work since these 
operations has consisted largely in the slow and painful restora- 
tion, by precise experimental methods, of what was thus wiped 
out at one fell swoop. The three authors named, with those 
that aided them, perhaps did the science of behavior the greatest 
possible service at that time. Before them there was hardly an 
ordered science in this subject; there was a jungle of supposi- 
tions, assumptions and anecdotes. Loeb, Bethe, Thorndike and 
Company destroyed all this and compelled us to rebuild from 
the ground up, a solid structure, based on precise scientific 
methods. How high the structure will have to go, no one 
ean foretell; certainly it is not yet finished. Indeed, animal 
behavior as a science is merely in its swaddling clothes; it can 
not carry as yet many sweeping conclusions, particularly nega- 
tive ones. General negations based on what we now know are 
most unscientific; they are largely capitalizations of our large 
stock of ignorance. It behooves the man of science, therefore, 
to be careful in his destructive criticisms; some recent contro- 
versies show that this caution is much needed. It will be long 
before our science is coextensive with the phenomena with which 
it is attempting to deal. H. S. JENNINGS. 

(No. 494 was issued on April 10, 1908.) 


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WALKER PRIZES IN NATURAL HISTORY 


By the provisions of the will of the late Dr. William Johnson Walker two 
prizes are annually offered by the Boston SOCIETY OF NATURAL HISTORY for the 
best memoirs written in z English language, on subjects proposed by a Committee 
appointed by the Counci 

= the best memoir a a prize of sixty dollars may be awarded ; if, how- 

th moir be one of marked merit, cay mount may be Hivecaiied to one 
‘ashen dollars, at the discretion of the Boman ttee. 

For the next best memoir a prize not cuss fifty dollars may be awarded. 

Prizes will not be awarded unless the memoirs presented are of adequate merit. 

The competition for these prizes is not restricted, but is open to all. 

Attention is especially called to the following points: 

1. In all cases the memoirs are to be based on a considerable body of original 
and unpublished work, accompanied by a general review of the literature of the 
subject 


Anything in the memoir which shall furnish proof of the identity of the 
author shall be considered as debarring the essay from competition. 

3. Preference will be given to memoirs showing intrinsic evidence of being 
based pts researches made directly in competition for the p 

ch memoir must be accompanied by a sealed tine enclosing the 

ae name and supersecribed with a motto corresponding to one borne by the 
manuscript, and must be in the hands of the Secretary on or before April 1st of the 
year for which the prize is offered. 

5. The Society assumes no responsibility for publication of manuscript 
submitted. 
sonia FOR 1908: 

An experimental study of inheritance in animals or plants. 2, A com- 
Tae study of the effects of close-breeding and cross-breeding in BEERA or plants. 
3. A study of animal reactions in relation to habit formation. 4. A physiological _ 
Maiy = one or poset) species e plants with mapet t leaf variation. 5. Fertiliza- 
: What proportion of a plant’s 
seasonal growth is euere in the winter büd? ? 7A A SEE study of the 
forms and processes discoverable along a wta shore line. 8. A problem in 
structural geology. 9. ka study of one or more geological horizons with a view to 
determining the different conditions obtaining at one time over a large area, as 
recorded by sediments and fossils. 

SUBJECTS FOR 1909: 
i. A geographic study of a district of varied features, presented as involving 


_ history of a thallophyte, with special reference to sporogenesis. 6. Contribution to 
_ our knowledge of response in plants. 7. The factors governing orientation in animal 
responses. 8. The relation between primary and secon rs in 
animals. 9. The activities of the animal body in relation to internal seeretions. 
Boston Society of Natural To 
ae - Boston, Mass., U. PA 

GLOVER M. ALLEN, Secretary 


VOL. XLII, NO. 496 


ped 
. 


IHE 


AMERICAN 
NATURALIST 


A MONTHLY JOURNAL 
DEVOTED TO THE NATURAL SCIENCES 
IN THEIR WIDEST SENSE 


CONTENTS 
Aspects of the Species Question, Introductory]Remarks. Professor D. S. 
JOHNBON. as a a ee ee a‘ 
The Taxonomic Aspect of the Species Question. Professor CHARLES E. 
BESSEY. 
The Taxonsmic Aspect ‘of the species Questioni. Dr. NATHANIEL LORD 
BRITTON. 


The Physiologic Kipot of the Species Gusta. Prothane 3. c. ARTHUR 
The Physiological Aspect of a Species. ; Dr. D. T. MacDOUGAL 
An Ecologic View of the Species Sonception: Professor FREDERIC E. 
CLEMENTS ‘ * F b ‘ 
An Ecological Aspect of the Conception of Species. . Dr. H.C. COWLES 
gpa of the Species Question. Professor J. M. COULTER, Dr. J. B. 
LLOCK, Professor T. J. BURRILL, E. G. HILL, Dr. G. H. SHULL, Dr 
z x HARRIS, A. E. HITCHCOCK 
Shorter Articles and Correspondence: Otter Sheep, Piotemir c. E Brisror. 
Notes and Literature: Exp ntal Zoology—Przibram’s Experime 
ology. M. PPE ER Sota on Fishes, Professor Haroko T, LEWIS 


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: : Ps: ; Act 5 OORO Maiy h3, 


THE 
AMERICAN NATURALIST 


VoL. XLII April, 1908 No. 496 


ASPECTS OF THE SPECIES QUESTION 


Ar the recent Chicago meeting of the Botanical Society 
of America, the afternoon of Wednesday, January 1, 
was devoted to a symposium on ‘‘ Aspects of the Species 
Question.’ The principal participants, who, upon invi- 
tation of the council, prepared and read papers at the 
Symposium, were: C. E. Bessey and N. L. Britton, who 
discussed the taxonomic aspect; J. C. Arthur and D. T. 
MacDougal, who spoke on the physiologic aspect; F. E. 
Clements and H. C. Cowles, who dealt with the ecologic 
aspect of the question. The reading of the papers was 
followed by an open discussion of the question by a 
number of the members present. The papers read and 
the corrected stenographic report of the discussion are 
printed below. 

; D. S. Jounson, 
Secretary. 
OFFICE OF THE SECRETARY, 
BALTIMORE, MD., March 1, 1908. 


27 


THE TAXONOMIC ASPECT OF THE SPECIES 
QUESTION 


PROFESSOR CHARLES E. BESSEY 


THE UNIVERSITY OF NEBRASKA 


As long as species were supposed to be actual things, 
‘‘created as separate kinds at the beginning,’’ that botan- 
ists ‘‘discovered,’’ as explorers discover islands in the 
ocean, there was no serious ‘‘species question.” <A 
botanist might make a mistake, and announce the dis- 
covery of a new species, when he had merely found a 
variety of an old species; as an explorer might mis- 
-takenly announce the discovery of a new island, when 
as a matter of fact he had only seen an unfamiliar coast 
of a long-known island. 

Nature produces individuals, and nothing more. She 
produces them in such countless numbers that we are 
compelled to sort them into kinds in order that we may 
be able to carry them in our minds. ‘This sorting is 
classification—taxonomy. But right here we are in dan- 
ger of misunderstanding the matter. We do not actually 
sort out our individuals. We imagine them sorted out. 
It is only to a very slight extent that the systematic 
botanist ever actually sorts out individuals. When he 
_ has a considerable number of individual dried plants in 
his herbarium, he may sort them out, but these are but 
an infinitesimal portion of all the individuals in the world 
that we imagine to be sorted, but that are actually un- 
sorted. 

So species have no actual existence in nature. They 
are mental concepts, and nothing more. They are con- 
ceived in order to save ourselves the labor of thinking 
in terms of individuals, and they must be so framed 
that they do save us labor. If they do not, they fail of 

218 


No. 496] ASPECTS OF THE SPECIES QUESTION 219 


their purpose. Here we perceive one of the principles 
which must control in the limitation of species. If we 
multiply our species unduly we approach too near to the 
individuals, and we are as much burdened as though we 
had not invented species. On the other hand, if we make 
too few species those we do make include so many varia- 
tions from the type that confusion results again. We 
must steer a course between these two extremes. 

I am well aware that every man who has split up 
species upon any pretext will at once lay his hand upon 
his heart and assure himself that he has done this very 
thing of avoiding these extremes. I have yet to find a 
man who has not felt that all of his species were con- 
servatively made, and that had he been radically inclined 
he could have made many more. And yet the fact re- 
mains that much of the species-making of recent years 
has rendered it vastly more difficult than formerly for 
us to obtain a grasp of the flora of a region. Instead of 
helping us, this perverted notion of the purpose and the 
proper limitation of species has actually proved to be a 
hindrance. How much, for example, does the average 
botanist know nowadays about the species of Crategus? 
It will not avail to say that ‘‘he knows as much as he ever 
did,’’ for once he did study them somewhat, but now he 
is compelled to pass them by as quite too difficult for him 
to undertake to distinguish with the time he has at his 
command. The inordinate multiplication of species has 
hindered instead of advanced our knowledge, and this 
fact is sufficient to condemn it utterly. 

We are in danger of destroying the usefulness of tax- 
onomy in our zeal for describing every differing form 
as a separate species. We have lost sight of the prim- 
itive reason for the formation of species, namely, that 
we should have fewer things to hold in mind. Primitively 
the aim was to have as few species as possible. Now 
too often we look upon the addition of new species as a 
contribution to knowledge, when, on the contrary, it may 
be a hindrance. 


220 THE AMERICAN NATURALIST [ Vou. XLII 


The Linnean conception of species may have been too 
broad, but it had the merit of being understood. It has 
yet to be shown that that conception of species has been 
outgrown. The human mind is pretty nearly the same 
to-day that it was a century and a half ago. The botan- 
ists of to-day may be able to recognize species where 
Linné, and DeCandolle, and Gray could not, but the dif- 
- ference is by no means great enough to warrant such 
great changes as have taken place in the conception of 
species by some recent systematists. The human mouth 
is probably a little smaller than it was thousands of 
years ago, and probably the tendency is to a reduction 
of its dimensions, but it certainly has not changed so 
much as to warrant a marked reduction in the size of 
‘tablespoons; much less does it give sanction to any pro- 
posal to reduce them to the size of miniature saltspoons! 
The old spoons that still fit the average human mouth 
very well are not likely to be displaced for much smaller 
ones. I think it is highly probable that in like manner 
we shall insist upon the old measure of species, for the 
good reason that it is still well fitted to our mental needs 
and mental capacity. The experience of botanists as a 
body sanctions the general idea and limitations of species 
as understood by Linné, by DeCandolle, by Gray, rather 
than that of the species-makers of recent years. This 
sanction is not in deference to authority, but for the rea- 
son that their species commend themselves to us. We 
prefer the Linnean idea of species not because it is 
Linnean, but because it is more useful than those pro- 
posed more recently. Probably one reason for the vogue 
of the Linnean conception of species for the past century 
and a half is that it is so well adapted to the mental 
requirements of botanists the world over. Linné was 
‘fortunate in. adopting a measure of species which was 
‘neither so small as to be difficult to apprehend, nor so 
large as to be cumbersome. It may have been by happy 
chance that he hit upon this acceptable measure of 
species; it is much more likely that it was but another 


No. 496] ASPECTS OF THE SPECIES QUESTION 221 


example of that genius which gave him such great pre- 
eminence among the botanists of his day, and enabled 
him to make so lasting an impression upon systematic 
botany. 

We have given a good deal of attention to the laws of 
botanical nomenclature, a matter of considerable, but 
by no means paramount, importance, while we have pretty 
largely neglected the far more important laws of botan- 
ical taxonomy. We have legislated at length in regard 
to names of species, genera, families, orders, and so on 
to the end of the list, while we have scarcely touched 
upon the far more important question of what these 
groups should be. We have been more concerned with 
the chaff than with the wheat itself. 

We are forced to the conclusion that we have rather 
foolishly spent our time in discussing the less important 
matters of nomenclature, while we have permitted an- 
archy to thrive in the far more important work of the 
making of species. We have had botanical congresses 
which formulated laws in regard to the naming of species, 
but as to the making of species each botanist is allowed 
to follow his own notions without any guide whatever, 
and what is worse still, without any restrictions. The 
result is what we should expect. It is confusion; it is 
scientific anarchy. If an indefinite number of men were 
to contribute stones for a building, there being no agree- 
ment among them as to shape or dimensions, what would 
be the result? No worse, I am sure, than what has oc- 
curred in the erection of that portion of the edifice of 
science with which we are concerned to-day. It is almost 
incredible that we should have permitted the present 
condition of taxonomy to continue. Why mere tyros, 
wholly untrained in the underlying principles of the 
science of classification, should be allowed to contribute 
to the confusion of taxonomy is a matter which may well 
make us marvel. But there have been words of admon- 
ition. Nearly thirty years ago Dr. Gray in his ‘‘Botan- 
ical Text-book’’ spoke of the necessity of experience and 


222 THE AMERICAN NATURALIST [ Vou. XLII 


‘‘the critical study of the classical botanical works,’’ and 
then said ‘‘No one is competent to describe new plants 
without such study.’ Wiser words in regard to the 
question before us were never written, and had they been 
heeded during the past quarter of a century we should 
not have had the present condition of confusion in sys- 
tematic botany. Certainly our practise of allowing 
everybody, whether trained for the work or not; to deter- 
mine the limits of species is taxonomic anarchy. 

It is increasingly evident that botanists must insist 
upon an adequate training by those who are proposing 
to make and describe new species. Every teacher of 
botany should impress his pupils with the seriousness 
of the work of making new species, and should train 
them to feel that such work should be left to the few 
who are masters in the subject. The rule which goes 
into effect to-day, requiring diagnoses of new species 
to be in Latin, will prove a deterrent to the tyros who 
would rush into print with their diffuse English de- 
scriptions. In this matter, at least, we should all uphold 
the Vienna code, and rigidly exclude as invalid all publi- 
cation of species not conforming to it. A more effective 
deterrent could be provided by an agreement of botanists 
to restrict publication to certain botanical journals, 
whose editors should then exercise a revisionary control 
over all publication of new species. I am well aware 
of the objection that will be made to such a taxonomic 
censorship, but we have gone so far in the direction of 
individual liberty that it has degenerated into license, 
and some such drastic measure is loudly called for. 
When we had masters in botany, who were kings to 
„whose authority all must bow, we complained bitterly. 
Now that the kings are dead the democracy of botany 
is suffering from the misrule of anarchy. If democracy 
will not control its subjects we shall have to return to 
a botanical oligarchy, or even to a dictatorship, for an- 
archy can not be endured. 

Has not the time come for botanists to establish rules 


No. 496] ASPECTS OF THE SPECIES QUESTION 223 


governing and restricting the making of species? I am 
convinced that the next step forward in systematic bot- 
any must be the placing of limitations upon the men 
who are setting up new species, compelling them to con- 
form their species to the conditions which make species 
necessary. 

Of course this is not the time, nor is it the place, for 
final action in regard to this matter, and, moreover, I 
am certainly not the one to formulate rules for species- 
making, yet I may be allowed to suggest some botanical 
dicta or aphorisms as a short prodrome of a taxonomic 
code. 

1. Taxonomy is a means, not an end; it does not exist 
for the taxonomists alone, but for the whole body of 
botanists. 

2. The first purpose of classification is to include all 
individual plants in as small a number of species as 
possible. 

3. That classification of the plants of the world most 
fully accomplishes its purpose which gives an adequate 
picture of the whole in the simplest form. 

4. Species have been invented in order that we may 
refer to great numbers of individuals collectively, in- 
stead of singly; therefore the number of species must 
be far less than the number of individuals. 

5. Since we make use of species for the purpose of 
saving labor in making the acquaintance of plants, it 
follows that those species whose limitations are so faint 
or vague that we apprehend them with difficulty have 
no reason for existence. 

6. Scientific classification does not require that every 
difference in structure and habit be made the basis of 
a separate species. There must be room left for indi- 
vidual variation, otherwise we should have as many 
species as there are individual variations. 

7. The taxonomist should look for resemblances rather 
than for differences, so that he may make fewer rather 
than more species. 


224 `. * THE AMERICAN NATURALIST [ Vou. XLIL 


8. Species must be so made as to be understood and 
appreciated by the botanists for whom they are described. 
A species has no legitimate reason for existence whose 
limits are perceptible only to its maker. 

9. Experience must tell us what limitations of species 
are most convenient. 

10. In making a species the guiding principle must be 
that it shall be recognizable from its diagnosis. A species 
that is not distinguishable by its diagnosis has no right 
to existence. 

11. A diagnosis should be brief enough to be remem- 
bered readily, for this reason Linné’s twelve- wo diag- 
noses are worthy of imitation. 

12. Long and complex descriptions should never be 
used for the limitation of species, and when such long 
and complex descriptions are found to be necessary this 
is a sufficient indication that the species should not be 
made. 

These aphorisms are merely illustrative, and by no 
means cover the whole ground. Others will suggest 
themselves, especiallý to those of you who have been 
engaged in taxonomic work. It seems to me so desirable 
that a reform in taxonomy should be instituted that I 
venture to suggest that this society appoint a committee 
to report upon the feasibility of restoring species to their 
original importance and dimensions, the possibility of 
restricting species-making to those who are competent, 
and also of restricting publication to selected journals, 
thus involving some kind of taxonomic censorship. 


THE TAXONOMIC ASPECT OF THE SPECIES 
QUESTION 


DR. NATHANIEL LORD BRITTON 


New York BOTANICAL GARDEN 
1. Historic 


THe ancients knew and described plants by generic 
names. Their knowledge of them was general and super- 
ficial. According to Adanson,! Conrad Gesner, 1559, 
was the first to indicate the distinction of plants into 
genera and species, although this advance is also claimed 
for Columna. Subsequent authors in general, for about 
a century, arranged species of plants under generic 
names, but without definite rules for the limitations of 
genera. Morison (1655), Ray (1682), and Tournefort 
(1694), defined genera with reference to their fruits and 
were followed by Linnezus. 

Ray regarded specific T R as those that are 
somewhat notable and fixed and not due to cultivation 
and which cultivation does not change. The way to 
determine these, according to him, is to grow them from 
seed, because all the differences which are found in dif- 
ferent plants grown from the same seed are accidental 
and not specific, but he was not always exact in OE 
this rule. 

Tournefort declared that it troubled him very little 
whether the plants he cited were species or varieties as 
long as they differed in remarkable and perceptible 
qualities; Adanson approves this view, remarking that 
it seems to him sufficient and reasonable. 


From Linnæus, Philosophia Botanica, 1751. 
We enumerate as many species as different forms 
were originally created. 
* Fam. des Plantes 1: 102. 1763. 
225 


226 THE AMERICAN NATURALIST [Vou. XLII 


There are as many species as the Infinite Being orig- 
inally produced different forms; and these forms, fol- 
lowing the laws of reproduction imposed upon them, 
have produced more, but always similar to themselves. 
Therefore, there are as many species as there are dif- 
ferent forms or structure met with to-day. 


From Adanson, Familles des Plantes, 1765. 

The moderns define a species of plant as a collection 
of several individuals which resemble each other per- 
fectly, yet not in everything, but in the essential parts 
and qualities, without, however, giving attention to the 
differences caused in these individuals either by sex or 
accidental varieties. 

According to Linneus (Phil. bot., p. 99) ‘‘the species 
of plants are natural and constant, as their propagation 
either by seeds or cuttings is only a continuation of the 
same species. Individuals die, but the species does not.”’ 

But we wish to make a distinction between reproduc- 
tion by seed and that by shoots, offsets, corms, cuttings, 
suckers or by grafting. These last simply continue the 
individual from which they are taken and consequently 
are opposed to the production of new species in plants; 
whereas seeds are the source of a prodigious number of 
varieties, sometimes so changed that they may pass 8 
new species. He cites, among other examples: 

‘‘In 1715 Marchant found in his garden a new species 
of Mercurialis and the following year it came from self- 
sown seed; again, four resembled the parent and two were 
so different that he made another species of Mercurialis. 
These two new plants were cultivated and continued to 
grow each year.” 

It is well known that without foreign fecundation in 
plants that reproduce by seed, similar changes are induced 
either by reciprocal fecundation of two different indi- 
viduals or owing to cultivation, the soil, the climate, 
dryness or moisture, light or shade, ete. These changes 
are more or less prompt, more or less durable, disap- 


~] 


No. 496] ASPECTS OF THE SPECIES QUESTION 227 
pearing in one generation or perpetuating themselves 
through several generations, according to the number, 
the force, the duration of the causes which united to 
form them, ete., according to the nature, the disposition, 
the customs, so to speak, of each plant, for it is to be 
noted that some families do not vary except in the roots, 
others in the leaves, others in height, pubescence, and 
color, whereas others change more easily their flowers 
or their fruit. 

It is difficult to define a primitive species and which 
those are which have originated by successive reproduc- 
tion or been changed by accidental causes. It is without 
doubt for this reason that we do not find nowadays a 
number of plants described by ancient botanists; they 
have disappeared, either by returning to primitive forms 
or by changing their form in the multiplication of species. 
For this reason the ancients knew fewer species; time 
has brought novelties! And for the same reason future 
botanists will be overwhelmed by the number of species 
and be obliged to abandon them and be reduced solely 
to genera! 


From Lamarck, Encyclopedie Methodique, Vol. 2, 1786. 

Species; in botany as in zoology, a species is neces- 
sarily constituted of the aggregation of similar indi- 
viduals which perpetuate themselves, the same, by re- 
production. I understand similarity in the essential 
qualities of the species, because the individuals which 
constitute it offer frequently accidental differences which 
give rise to varieties and sometimes sexual differences, 
which belong however to the same species, as the male 
and female hemp, in which all the individuals constitute 
the common cultivated hemp. Thus, without the con- 
stant reproduction of similar individuals, there could not 
exist a true species. 


From Rees, Abraham, The Cyclopedia, Vol. XXXIII, 
1819. 


Species of Plants, in Systematic Botany, appear, as 


228 THE AMERICAN NATURALIST [ Vou. XLII 


far as can be ascertained from the universal experience 
of those who are conversant with them, as well as from 
everything that can be gathered from the records of 
remote antiquity, to remain distinct from each other, 
marked by their appropriate characters and qualities, 
and renewing themselves periodically by sexual genera- 
tion. Such being the case with all the plants of which 
we have any knowledge, we conclude it to be so with the 
rest, as well as with animals. The white blackbird of 
Aristotle still inhabits the Cyllenian groves and copses 
of Areadia, undisturbed by the revolutions of two thou- 
sand years; and we doubt not that the banks of the 
Alpheus have been fringed with the same violets and 
primroses, through uncounted ages, as those with which 
they are now, every spring, adorned. 

Various plants indeed, and especially domestic ones, 
like domestic animals, are found lable to some varia- 
tions of color, luxuriance, and sensible qualities, which 
have led curious inquirers to doubt whether any species 
are certainly permanent. This doubt could arise only 
from a slight view of the subject. Whatever casual 
aberrations there may be in the seminal offspring of 
cultivated plants, a little observation will prove how 
transient such varieties are, and how uniformly their 
descendants, if they be capable of producing any, resume 
the natural characters of the species to which they belong. 


From A. P. DeCandolle and K. Sprengel, Elements of 

the Philosophy of Plants, Edinburgh, 1821. 

By species we understand a number of plants, which 
agree with one another in invariable marks. 

In this matter everything depends upon the idea of 
invariableness. When an organ, or a property of it, 
is changed neither by difference of soil, of climate, or of 
treatment, nor by continued breeding, this organ or prop- 
erty is said to be invariable. When, for instance, we 
have remarked during centuries, that the centifolia has 
always unarmed leafstalks, we say correctly, that this 
property of the centifolia is invariable. 


No. 496] ASPECTS OF THE SPECIES QUESTION 229 


This idea proceeds on the supposition that the species 
which we know have existed as long as the earth has had 
its present form. No doubt there were, in the preceding 
state of our globe, other species of plants, which have 
now perished, and the remains of which we still find in 
impressions in shale, slate-clay, and other flœtz rocks. 
Whether the present species, which often resemble these, 
have arisen from them; whether the great revolutions on 
the surface of the earth, which we read in the Book of 
Nature, contributed to these transitions—we know not. 
What we know is that from as early a time as the human 
race has left memorials of its existence upon the earth 
the separate species of plants have maintained the same 
properties invariably. 

To be sure, we frequently speak of the transitions and 
crossings of species; and it can not be denied that some- 
thing of this kind does occur, though without affecting 
the idea of species which we have proposed. We must, 
therefore, understand this difference. 

We perceive the Transitions of a Species, when it loses 
or changes the properties, which we had considered as 
invariable in the character. Thus, it would be a transi- 
tion, if we had stated as an invariable character of winter 
wheat (Triticum hybernum), that it was biennial, and 
had an ear without awns; and if we should remark, that 
by frequent reproduction, and by very different treat- 
ment, it began to assume awns, and, when sown in spring, 
came to maturity during the same summer. 

But this shows only that our idea of the difference 
between the two kinds of grains had been incorrect; for 
it is the universal rule, that the character does not con- 
stitute the species, but the species the character. Species, 
then, only appear to undergo transitions, when we have 
considered an organ or a property as invariable which 
is not so. 

All properties of plants which are subject to change, 
form either a subspecies or a variety. By the former 
we understand such forms as continue indeed during 


230 THE AMERICAN NATURALIST [ Von. XLII 


some reproductions, but at last, by a greater difference 
of soil, of climate, and of treatment, are either lost or 
changed. When the different cabbage species receive 
the same treatment in the same climate, they continue 
to be frequently reproduced, without changing their ap- 
pearance. But we can not on this account maintain, that 
cauliflower would retain the same favorite form in very 
different climates, and under a complete change of treat- 
ment. It at last changes so much, that it can scarcely 
be distinguished from the common cabbage. This, there- 
fore, is a subspecies. Varieties again do not retain 
their forms during reproduction. The variable colors 
—the very variable taste, and other properties of the 
kitchen vegetables, the ornamental plants, and the fruit- 
trees, show what varieties are; and the scientific botan- 
ist must therefore be particularly attentive to distinguish 
permanent species from the variable subspecies, degen- 
erate plants and varieties. 

To this discrimination belongs, above all things, a 
careful, continued, and unprejudiced observation of the 
whole vegetation of the same plant during its different 
ages, and amidst the most different circumstances which 
have an influence on it. When, for instance, in the com- 
mon Lotus corniculatus, on whatever soil it may grow, 
we uniformly observe that it has a solid stem, even and 
erect divisions of the calyx, and expanded filaments, we 
must of necessity distinguish, as a particular species 
from it, another form which grows in bogs and in watery 
meadows, which has a much higher, and always hollow 
stalk, the divisions of its calyx spread out into a star- 
shape and hairy, and which has uniformly thin fila- 
ments; and we must name this latter species either Lotus 
uliginosus with Schkuhr, or Lotus major with Scopoli 
and Smith. As, on the other hand, the Pimpinella Saxi- 
fraga grows sometimes quite smooth, and sometimes in 
woods and shady meadows, considerably hairy; as it 
displays sometimes simple and small stem-leaves, some- 
times half and even doubly pinnated leaves; and as these 


No. 496] ASPECTS OF THE SPECIES QUESTION 231 


forms vary according to the situation of the plant and 
during reproduction, we can not regard these’ forms by 
any means as distinct species, but we must view them as 
corruptions. 

We see, that, in order to decide respecting the idea of 
a species, an observation of many years, and of much 
accuracy, is often required; and that the cultivation of 
plants, from the most different climates, in botanical 
gardens, is in the highest degree necessary for their dis- 
crimination. 


From Lindley, John, An Introduction to Botany, Lon- 

don, 1832. 

A species is a union of individuals agreeing with each 
other in all essential characters of vegetation and fructi- 
fication, capable of reproduction by seed without change, 
breeding freely together, and producing perfect seed 
from which a fertile progeny can be reared. Such are 
the true limits of a species; and if it were possible to 
try all plants by such a test, there would be no difficulty 
in fixing them, and determining what is species and what 
is variety. But, unfortunately, such is not the case. 
The manner in which individuals agree in their external 
characters is the only guide which can be followed in the 
greater part of plants. We do not often possess the 
means of ascertaining what the effect of sowing their 
seed or mixing the pollen of individuals would be; and, 
consequently, this test, which is the only sure one, is, in 
practice, seldom capable of being applied. The deter- 
mination of what is a species, and what a variety, be- 
comes therefore wholly dependent upon external char- 
acters, the power of duly appreciating which, as indic- 
ative of specific difference, is only to be obtained by ex- 
perience, and is, in all cases, to a certain degree arbitrary.. 
It is probable that, in the beginning, species only were 
formed; and that they have, since the creation, sported 
into varieties, by which the limits of the species them- 
selves have now become greatly confounded. For ex- 


232 THE AMERICAN NATURALIST [Vor. XLII 


ample, it may be supposed that a rose, or a few species 
of rose, were originally created. In the course of time 
these have produced endless varieties, some of which, 
depending for a long series of ages upon permanent 
peculiarities of soil or climate, have been in a manner 
fixed, acquiring a constitution and physiognomy of their 
own. Such supposed varieties have again intermixed 
with each other, producing other forms, and so the opera- 
tion has proceeded. But as it is impossible, at the 
present day, to determine which was the original or orig- 
inals, from which all the roses of our own time have 
proceeded, or even whether they were produced in the 
manner I have assumed; and as the forms into which 
they divide are so peculiar as to render a classification 
of them indispensable to accuracy of language; it has 
become necessary to give names to certain of those forms, 
which are called species. Thus it seems that there are 
two sorts of species: the one, called natural species, de- 
termined by the definition given above; and the other, 
called botanical species, depending only upon the ex- 
ternal character of the plant. The former have been 
ascertained to a very limited extent; of the latter nearly 
the whole of systematic botany consists. In this sense 
a species may be defined to be ‘‘an assemblage of indi- 
viduals agreeing in all the essential characters of vegeta- 
tion and fructification.’’ Here the whole question lies 
with the word essential. What is an essential character 
of a species? This will generally depend upon a prone- 
ness to vary, or to be constant in particular characters, 
so that one class of characters may be essential in one 
genus, another class in another genus; and these points 
can be only determined by experience. Thus, in the 
genus Dahlia, the form of the leaves is found to be sub- 
ject to great variation; the same species producing from 
seed, individuals, the form of whose leaves vary in a 
very striking manner; the form of the leaves is, there- 
fore, in Dahlia, not a specific character. In like manner, 
in Rosa, the number of prickles, the surface of the fruit, 


No. 496] ASPECTS OF THE SPECIES QUESTION 235 


or the surface of their leaves, and their serratures, are 
found to be generally fluctuating characters, and can not 
often be taken as essential to species. The determina- 
tion of species is, therefore, in all respects, arbitrary, 
and must depend upon the discretion or experience of the 
botanist. 


From Nicholson, Henry Alleyne, A Manual of Zoology, 

New York, 1876. 

Species.—No term is more difficult to define than 
‘‘ species,” and on no point are zoologists more divided 
than as to what should be understood by this word. 
Naturalists, in fact, are not yet agreed as to whether the 
term species expresses a real and permanent distinction, 
or whether it is to be regarded merely as a convenient, 
but not immutable, abstraction, the employment of which 
is necessitated by the requirements of classification. 

By Buffon, ‘‘species’’ is defined as ‘‘a constant suc- 
cession of individuals similar to and capable of reprodu- 
cing each other.’’ 

DeCandolle defines species as an assemblage of all 
those individuals which resemble each other more than 
they do others, and are able to reproduce their like, 
doing so by the generative process, and in such a manner 
that they may be supposed by analogy to have all de- 
scended from a single being or a single pair. 

M. de Quatrefages defines species as ‘‘an assemblage 
of individuals, more or less resembling one another, 
which are descended, or may be regarded as being de- 
scended, from a single primitive pair by an uninterrupted 
succession of families.” 

Miiller defines species as ‘‘a living form, represented 
by individual beings, which reappears in the product of 
generation with certain invariable characters, and is con- 
stantly reproduced by the generative act of similar in- 
_ dividuals.” 

According to Woodward, ‘‘all the specimens, or indi- 
viduals, which are so much alike that we may reasonably 


Zor THE AMERICAN NATURALIST [ Vou. XLII 


believe them to have descended from a common stock, 
constitute a species.’’ 

From the above definitions it will be at once evident 
that there are two leading ideas in the minds of zool- 
ogists when they employ the term species; one of these 
being a certain amount of resemblance between indi- 
viduals, and the other being the proof that the individuals 
so resembling each other have descended from a single 
pair, or from pairs exactly similar to one another. The 
characters in which individuals must resemble one an- 
other in order to entitle them to be grouped in a separate 
species, according to Agassiz, ‘‘are only those determin- 
ing size, proportion, color, habits and relations to sur- 
rounding circumstances and external objects.’’ 

On a closer examination, however, it will be found that 
these two leading ideas in the definition of species—ex- 
ternal resemblance and community of descent—are both 
defective, and liable to break down if rigidly applied. 
Thus, there are in nature no assemblages of plants or 
animals, usually grouped together into a single species, 
the individuals of which exactly resemble one another 
in every point. Every naturalist is compelled to admit 
that the individuals which compose any so-called species, 
whether of plants or of animals, differ from one another 
to a greater or less extent, and in respects which may be 
regarded as more or less important. The existence of 
such individual differences is attested by the universal 
employment of the terms ‘‘varieties’’? and ‘‘races.’’ 
Thus a ‘‘variety’’ comprises all those individuals which 
possess some distinctive peculiarity in common, but do 
not differ in other respects from another set of individ- 
uals sufficiently to entitle them to take rank as a separate 
species. A ‘‘race,’’ again, is simply a permanent or 
‘*nerpetuated’’ variety. The question, however, is this 
—How far may these differences amongst individuals 
obtain without necessitating their being placed in a 
separate species? In other words: How great is the 
amount of individual difference which is to be considered 


No. 496] ASPECTS OF THE SPECIES QUESTION 235 


as merely ‘‘varietal,’’ and at what exact point do these 
differences become of “‘ specific’? value? ‘To this ques- 
tion no answer can be given, since it depends entirely 
upon the weight which different naturalists would attach 
to any given individual difference.2 Distinctions which 
appear to one observer as sufficiently great to entitle the 
individuals possessing them to be grouped as a distinct 
species, by another are looked upon as simply of varietal 
value; and, in the nature of the case, it seems impossible 
to lay down any definite rules. To such an extent do 
individual differences sometimes exist in particular 
genera—termed ‘‘protean’’ or ‘‘polymorphic’’ genera— 
that the determination of the different species and vari- 
eties becomes an almost hopeless task. 

The second point in the definition of species—namely, 
community of descent—is hardly in a more satisfactory 
condition, since the descent of any given series of indi- 
viduals from a single pair, or from pairs exactly similar 
to one another, is at best but a probability, and is in no 
case capable of proof. 

Upon the whole, then, it seems in' the meanwhile safest 
to adopt a definition of species which implies no theory, 
and does not include the belief that the term necessarily 
expresses a fixed and permanent quantity. Species, 
therefore, may be defined as an assemblage of individuals 
which resemble each other in their essential characters, 
are able, directly or indirectly, to produce fertile indi- 
viduals, and which do not (as far as human observation 
goes) give rise to individuals which vary from the gen- 
eral type through more than certain definite limits. The 
production of occasional monstrosities does not, of 
course, invalidate this definition. 


From Gray, Asa, Structural Botany, Ed. 6, 1879. 
Species in biological natural history is a chain or series 
* As an example of this, it is sufficient to allude to the fact that hardly 
any two botanists agree as to the number of species of willows and 
brambles in the British Isles. What one observer classes as mere varieties, 
another regards as good and distinct species. 


236 THE AMERICAN NATURALIST [ Vou. XLII 


of organisms of which the links or component individ- 
uals are parent and offspring. Objectively, a species is 
the totality of beings which have come from one stock, 
in virtue of that most general fact that likeness is trans- 
mitted from parent to progeny. Among the many defini- 
tions, that of A. L. Jussieu is one of the briefest and 
best, since it expresses the fundamental conception of 
a species, 7. e., the perennial succession of similar indi- 
viduals perpetuated by generation. 

The two elements of species are: (1) community of 
origin; and, (2) similarity of the component individuals. 
But the degree of similarity is variable, and the fact of 
genetic relationship can seldom be established by ob- 
servation or historical evidence. It is from the likeness 
that the naturalist ordinarily decides that such and such 
individuals belong to one species. Still the likeness is 
a consequence of the genetic relationship; so that the 
latter is the real foundation of species. 

No two individuals are exactly alike; and offspring of 
the same stock may differ (or in their progeny may come 
to differ) strikingly in some particulars. So two or 
more forms which would have been regarded as wholly 
distinct are sometimes proved to be of one species by 
evidence of their common origin, or more commonly are 
inferred to be so from the observation of a series of 
intermediate forms which bridge over the differences. 
Only observation can inform us how much difference is 
compatible with a common origin. The general result 
of observation is that plants and animals breed true 
from generation to generation within certain somewhat 
indeterminate limits of variation; that those individuals 
which resemble each other within such limits interbreed 
freely, while those with wider differences do not. Hence, 
on the one hand, the naturalist recognizes varieties or 
differences within the species, and on the other genera 
and other superior associations, indicative of remoter 
relationship of the species themselves. 


No. 496] ASPECTS OF THE SPECIES QUESTION 237 


From Darwin, Origin of Species, new edition, from the 

sixth English edition, New York, p. 33, 1883. 

No one definition has satisfied all naturalists; yet every 
naturalist knows vaguely what he means when he speaks 
of a species. . . . The term variety is almost equally 
difficult to define; but here community of descent is 
almost universally implied, though it can rarely be 
proved. 


From Britton and Brown, Illustrated Flora 1: VI., 1896. 

A species is composed of all the individuals of a kind 
capable of continuous successive propagation among 
themselves. 


From De Vries, Species and Varieties, p. 32, 1905, under 

Elementary Species in Nature. 

‘What are species?’’ Species are considered as the 
true units of nature by the vast majority of biologists. 
They have gained this high rank in our estimation prin- 
cipally through the influence of Linneus. They have 
supplanted the genera which were the accepted units 
before Linneus. They are now to be replaced,.in their 
turn, by smaller types, for reasons which do not rest 
upon comparative studies but upon direct experimental 
evidence. 


2. Discussion 


Any method of evolution makes difficult the establish- 
ment as a general conclusion, that all the progeny of a 
species must belong to that species. The paleontologists 
have always faced this difficulty; their species have of 
necessity been assumptions, and theoretically, at least, 
if the complete representation of any line of descent 
could be assembled it would be seen at once that the 
whole series of forms were in some way connected. The 
induced mutation effected by MacDougal in Raimannia 
odorata, in which plants so different from their imme- 
diate parent as to appear, at least, specifically distinct 


238 THE AMERICAN NATURALIST [ Vou. XLII 


from it, as compared with other feral species, is a notable 
addition to the difficulty of maintaining such a conclusion. 

As long as species were generally understood to be 
relatively fixed in characters, their delimitation was rel- 
atively simple, but the general understanding that all 
living organisms are descended from others which were 
different from them has greatly complicated the subject. 

Whether the evolution has been by imperceptible pro- 
gressive modifications of structure, or by mutations, or 
by both methods, the result is essentially the same from 
the practical standpoints of taxonomy; from these stand- 
points, then, similarity of individuals must remain the 
consideration to which most weight will be given in 
taxonomic usage. It has been conclusively proved that 
many mutants and elementary species or races breed 
true in enough instances to establish the rule for at least 
a number of generations; this should not, however, in 
my opinion, admit them to the category of species, which, 
though necessarily difficult in delimitation, will still re- 
main the practical taxonomic groups, recognizing, never- 
theless, that they are made up of either relatively con- 
stant or of widely fluctuating elementary components, 
which, in turn, will presumably yield the species of future 
geologic ages. 

The recognition of the existence of incipient or ele- 
mentary species or races within the composition of 
species, explains, in large part, the multiplication of 
species and of groups of assumed lower rank, in many 
of the larger genera, nearly every taxonomist, except the 
most conservative, having taken more or less part in thus 
increasing the number of descriptions and of names. 
They have been variously denominated species, sub- 
species, varieties, subvarieties and forms, according to 
the point of view of the investigator. : 

Geographic distribution has been invoked as a very 
useful aid in determining the limits of species. It is a 
well-recognized fact that certain areas of the earth’s sur- 
face, some large, some small, are characterized by types 


No. 496] ASPECTS OF THE SPECIES QUESTION 239 


of plants which differ from those of other areas, either 
contiguous or widely separated, and, in cases where 
types inhabiting different areas so characterized are ap- 
parently similar, though different, their separation or 
isolation has been given weight in regarding them as 
specifically distinct. No doubt this is a rational course 
to pursue if it is not carried to extremes. The question 
whether the environments to which the ancestors of such 
types have been exposed have been the cause of their 
differentiation, or whether the elementary species have 
been perpetuated which were best adapted to the soil, 
climate or other features of the environments, is one of 
the most interesting of unsolved problems. That similar 
types have for the most part come from common ances- 
tors we must regard as most probable, even if now in- 
habiting widely separated regions, segregated by the 
disappearance of related types in intervening space, be- 
ing thus remnants of the more general distribution of 
the ancestral forms in earlier geologic eras. 

Geographic distribution must, however, in cases of 
contiguous land districts, be cautiously used as a deter- 
mining factor. There are many instances in which a 
species with certain well-marked characters in one region 
is, apparently, at least, completely connected through 
intermediate characters with what is readily regarded as 
a perfectly distinct species in another region. Instances 
of this kind are within the experience of every one who 
has given attention to geographic distribution of plants. 
I say this is apparently the case; the conclusion is based 
on long series of herbarium specimens and on field obser- 
vations made over large areas of country. Neither of 
these methods of information is wholly satisfactory, 
because the herbarium series must necessarily be limited 
in the number of specimens, and also because the field 
observations have to be taken at different times and usu- 
ally at widely separated intervals. Still, the consensus 
of opinion of plant geographers leans strongly to the 
existence of intermediate forms in intermediate regions. 


240 THE AMERICAN NATURALIST [ Von. XLII 


Some of these are almost certainly hybrids, but it would 
not be safe for us to conclude that they all are. Some 
light has been thrown on this question by the growing 
of the extreme forms side by side, and more informa- 
tion can doubtless be thus obtained, the principal diff- 
culty being that the environment of the one is often fatal 
to the other. A better method would be to grow the 
two apparent extremes within the natural environment 
of the apparent intermediates. 


3. Tue Taxonomic TREATMENT OF GROUPS ASSUMED TO 
BE OF LowER RANK THAN SPECIES 


There is perhaps no taxonomic subject on which 
greater diversity of opinion and practise exists than in 
the arrangement and nomenclature of groups of individ- 
uals not accorded full specific value. The relationships 
of these groups to the group assumed to constitute the 
species proper, and the nomenclature of these subsidiary 
groups, vary all the way from regarding them all as 
species, to regarding some of them as subspecies, some 
as varieties, some as subvarieties, others as forms, while 
even finer distinctions have been attempted, and elabo- 
rate monographs of many genera have been written in the 
attempt to express descriptively these interrelationships. 
It has been very evident that these described groups 
are of unequal value, some resembling the assumed typ- 
ical group more, some less, and in a good many instances 
very little. The general result of these attempts to dis- 
sect nature has been embarrassing, because when a sub- 
sequent student takes up the group he is wholly unable 
to determine from any descriptions that can be written 
where any given individual would have been grouped by 
the previous author, unless he has access to the uctual 
specimens which the previous author studied, and the 
subsequent student also finds that the examination of a 
large number of different individual specimens from 
those studied by his predecessor contains some which 


No. 496] ASPECTS OF THE SPECIES QUESTION 241 


do not fully agree with any one of his predecessor’s de- 
scriptions, or he finds that some of his specimens agree 
about as well with one of the groups recognized by the 
previous author as they do with another. ‘This result 
shows conclusively that for practical taxonomic pur- 
poses it is not desirable to attempt to define a great many 
of these minor groups. The tendency has been brought 
about, I believe, by the instinct of many investigators 
that everything in nature must be named and described, 
but nothing is to be gained by permitting this laudable 
purpose to run to extremes. 

It is evident, I think, that our taxonomy has been 
based on the fundamental error that the plant world 
is to be regarded as divisible into smaller and smaller 
groups, rather than following nature and proceeding on 
the theory that it is built up of greater and greater ones; 
the science should be synthetic rather than analytic. 
The synthetic theory will give our observation and ex- 
perimentation a different significance and enable us to 
comprehend some of the phenomena now masked by the 
analytic method of attack. 

If, as now seems more probable than a few years ago, 
species are made up of elementary species, or races, and 
that these are being increased by mutation, there can be 
no end to the number of such groups produced. As 
to the designation of these groups, I suggest that the 
term race be employed. This has long been used to 
designate what have been called self-perpetuating ‘vari- 
eties, which appear to me to be identical with the present 
conception of elementary species, and its application may 
readily be widened. The term variety loses its signifi- 
cance, because it is usually quite impossible to tell how 
any given individual or group of individuals has arisen, 
or from which species it has sprung. The term form could 
be used instead of either-race or elementary species, but 
it has had such a trivial signifieane i 
race seems to be preferable. Subspe 
bility, and is, therefore, an undesirable term. 


242 THE AMERICAN NATURALIST [ Vou. XLII 


In conclusion, I submit the following propositions: 

1. The individual is the taxonomic unit, usually un- 
designated. 

2. Similar individuals constitute a race. 

For general taxonomic purposes races need not be 
designated; the conception and description of the species 
is broad enough to include all races of which it is com- 
posed. There will never be complete uniformity of 
agreement as to the distinction between races and species, 
any more than there will ever be complete agreement as 
to the limitations of genera. It is futile in science to 
attempt to lay down principles which interfere with indi- 
vidual judgments. For special purposes the races may 
be designated numerically, as, Quercus alba, race 2; 
(Enothera biennis, race 12; Bursa Bursa-pastoris, race 17 ; 
Draba verna, race 104. There are doubtless many in- 
stances where the species is composed of only one race, 
just as we have monotypic genera composed of but one 
species. 

3. Similar races constitute a species, the species des- 
ignated binomially. 

4. Similar species constitute a genus, the genus des- 
ignated monomially. 


THE PHYSIOLOGIC ASPECT OF THE SPECIES 
QUESTION 


PROFESSOR J. C. ARTHUR 


PURDUE UNIVERSITY 


Nor being sure of what ground might already be 
covered by the speakers who have preceded me on the 
program, I take the liberty of presenting my matter 
after giving thought to what has been said; and I find in 
mentally reviewing this—that the species concept as 
presented by the previous speakers does not embrace the 
whole field as it is forced upon me in my every-day work. 
I am especially surprised at this, because the first speaker, 
under whom I secured my elementary training in botany, 
is very particular in giving instruction to his pupils to 
begin with the one-cell plant and to work up from the 
simple to the complex. Yet, so far as I could ascertain 
in listening most carefully, he has not now taken into con-. 
sideration a single one of the simple plants of which he 
knows there are many thousand times as many as there 
are of flowering plants, therefore I seem to be left some- 
what adrift for my presentation. 

I will not attempt to give any historical aspect of the 
question, but to take it up from the point in which it 
-= appeals to me in my every-day work, for it is a problem 
that I have been obliged to meet, and as I have met it, 
I will present the results to you. 

_ As I understand it, we are taking up the question of 
the species concept. I thought it quite well worth while, 
in looking up the matter, to see what a man who has en- 
tirely changed the aspect of the subject within not so 
very many years might say as to what he considered a 
Species concept, and so I very carefully again looked 
through my copy of Darwin’s ‘‘Origin of Species.” If 


244 THE AMERICAN NATURALIST [ Vou. XLII 


a man were going to revolutionize the world of thought 
he certainly, I assumed, would give a definition of the 
subject he is going to treat. But I could not find a ~ 
word as to what Darwin meant by species. He writes 
as if all the world knew what species are. Yet I did 
find this in the latter part of the last chapter; he says, 
‘t And now we shall be freed from the vain search for the 
undiscovered and undiscoverable essence of the term 
species.’’ Consequently, here we are, tracing a will-o’- 
the-wisp. And yet, it seems to me, there must be some- 
thing that we are all thinking about when we say species. 
There must be some workable idea. Of course I know 
that since Darwin’s time and the vast accumulation of 
knowledge in reference to heredity and variation, to say 
nothing about other physiological aspects proper, our 
ideas have decidedly changed. Still, as I look over 
the actual work being accomplished in determining the 
number and the extent of the species of plants in the 
world, I do not see that our practise especially differs 
from the pre-Darwinian practise. We have a theoret- 
ical idea of what species are, but practically we describe 
them for the most part in the same pre-Darwinian terms, 
the really Linnean terms, so far as many of us can, 
although we do not adhere to the Linnean brevity. 
Nevertheless, there are some instances in which it seems 
necessary to deviate from this practise, if we wish to 
handle our subject in such a way as to make it useful; 
for I assume, in the first place, that whatever the species 
concept may be, it is something which enables us to 
present ideas or problems in a better form than we could 
otherwise accomplish. At any rate, the idea of a species 
is a mental tool of some sort. 

To take up the purely physiological aspect; possibly 
it was the study of bacteria which forced this phase of 
the question upon us for the first time. I judge that it 
came largely from the fact that bacteria are so very 
minute. What could one do if he were going to describe 
the thousands of species of bacteria simply as plants, | 


No. 496] ASPECTS OF THE SPECIES QUESTION 245 


with genera and life history as in the case of other 
plants? In the first place, morphological characters are 
too ill-defined, if indeed they exist, and so he was forced 
to devise some other means of discrimination. This 
means was at first almost purely physiological. It 
largely depended upon the behavior of the individual 
sorts, or the groups of individual sorts, to certain nutri- 
tive processes. It depended upon what kind of media 
the bacteria grow upon, the temperature, and access to 
oxygen. Upon these physiological results in large part 
have been built our vast knowledge, economic very 
largely, of the many kinds of bacteria which are desig- 
nated as species. But we may pass by the bacteria for a 
time and take up the larger organisms. I think the ones 
that are most useful in this connection are the strictly 
parasitic forms. 

There is no more interesting and better understood 
group at the present time than the plant-rusts. The 
forms are sufficiently large to furnish a variety of species 
and genera exhibiting morphological characters, and yet, 
being strictly parasitic, are particularly restricted by the 
nature of the substratum. I will give one or two in- 
stances to illustrate. There is a group of forms—I will 
admit that I hardly know what terms to use in speaking 
of them, but I will say a group of forms—which grow 
upon the various species of Carex. It is found that by 
taking rust spores from a single host of any particular 
Carex and sowing them upon an Aster, or a Solidago or 
an Erigeron, they will grow upon one of these genera, 
it makes not much difference what the species, but not 
upon the other two. Now if spores are taken from 
another Carex, the spores being so exactly like the former 
that they can not be distinguished by any visible char- 
acters, and sown upon plants of the same three genera, 
they may grow upon a different one than in the former 
instance, but not upon the remaining two. Thus finally 
we will get three sets of forms, one growing on Aster, 
one on Solidago and one on Erigeron, which can not be 


246 THE AMERICAN NATURALIST [ Von. XLII 


made to interchange, although they possess no evident 
morphological differences. This result depends, as I 
assume and as seems to be pretty well authenticated 
by all the researches, upon a question of nutrition. It 
does not depend upon any peculiar structure of Aster, 
Solidago or Erigeron; but here we have three genera 
which furnish different kinds of nutritive matter, or in 
some way differently affect the nutrition of the fungus, 
so that a fungus which has adapted itself to live upon 
one of these generic groups of plants will not live upon, 
or can not live upon, the other. It is a very nice adjust- 
ment to a particular kind of nutriment; I think we are 
quite well assured of that fact. 

Now, the question arises, are these three species? If 
you choose to look up the literature, you will see that 
the speaker has described them as three species under 
three independent names. That does not mean that he 
believes they are truly three species, but that it was a 
convenient way of designating the three physiologically 
different kinds until a time when the matter could be 
more fully considered. Now, are these three species? 
Well, to confess to you, not to say it too loudly, I do not 
believe they are. They are not three species in the gen- 
erally accepted sense because they can not be distin- 
guished morphologically. What then is, or should be, 
our conception of a species? Is it something to be dis- 
tinguished physiologically or morphologically, or in both 
ways? This is not a hypothetical question, because the 
literature of the subject that I represent is very full of 
descriptions of species based entirely or partially upon 
physiological data, and I am assured that we are not 
alone in this method of describing species. 

If I understand aright, the ornithologists, at least 
some of them, are willing to assert that species may 
differ by characters which can not be deseribed by words 
[laughter]; that is to say, you will know the species 
when you see it, but you can not describe it in any lan- 
guage by which another person may recognize it. I 


a 


No. 496] ASPECTS OF THE SPECIES QUESTION 247 


think that this is not a joke, but that it is really stated 
in earnest; because, I read it in Science. [Laughter.] 
But I fancy botanists have not gone quite that far. 

Now, just another instance that arose during an ex- 
tensive series of culture studies; that is the case of the 
Helianthus rusts. They have been described according 
to the host plants on which they grow. Each species 
of Helianthus and its close relatives appear to bear 
a distinct kind of rust, which acts in cultures as if it 
were an independent species. Yet any and all of these 
will grow on Helianthus annuus, a so-called bridging 
host. Are these different species different biological or 
physiological species, or simply forms or races? Pos- 
sibly it would be well to refer them to some sub-category, 
as Dr. Britton has suggested. 

I think when we come to study other parasitic forms 
thoroughly we shall find this condition equally true, for 
instance, in the genus Cuscuta among flowering plants. 
Furthermore it is probably true in many cases of plants 
which are not parasitic. We had an illustration this 
morning in the cultures of Penicillium exhibited by Dr. 
Thom, where characters of taxonomic importance were 
developed according to the medium on which the fungus 
was grown. 

It seems highly probable that a physiological cause 
for variation, which may be considered as specific under 
many circumstances, could be traced throughout the 
vegetable kingdom. For purposes of study I assume 
that in most cases of physiological species, they may 
develop in the course of time into true taxonomic species, 
having distinct morphological characters, and that in 
cases such as I have enumerated, we are dealing with 
nascent species. The rules which have been laid down 
in the presentation of the subject by the previous 
speakers apply more particularly, I think, to forms well 
differentiated morphologically. But due recognition 
should be given to forms of physiological origin, as I 
have shown. Finally, I would say, at least it is a rule 


cat 


248 THE AMERICAN NATURALIST [ Von. XLII 


which I have formulated for my own guidance—it was a 
necessity that I should formulate some rule—that species, 
which are concepts, as I take it, for our convenience in 
discussing the various questions pertaining to plants, 
should be distinguished by sufficient morphological char- 
acters, the distinctions based upon physiological differ- 
ences having subspecific rank. What constitute suffi- 
cient morphological characters must be left to the indi- 
vidual judgment. 


THE PHYSIOLOGICAL ASPECT OF A SPECIES 


DR. D. T. MACDOUGAL 


CARNEGIE INSTITUTION OF WASHINGTON 


THe simple recognition of different kinds of plants 
must be of great antiquity, and perhaps no single idea 
affords a better index of scientific thought during the 
last few centuries than the species conception. The 
oceasion does not warrant a detailed statement of its de- 
velopment farther back than the time of Linnzus, who 
gave the idea a distinctly morphological stamp which it 
has retained to the present day. His systematization of 
natural objects marked the beginning of a period in 
which the morphological view of nature has prevailed 
throughout, the mechanics of form reaching its very 
apotheosis in the writing of De Candolle, De Bary, Hof- 
meister, Schwendener and a score of other eminent in- 
vestigators who have triangulated the field of natural 
history of plants, basing relationships and constructing 
Systems of phylogeny upon pure form, and upon the 
mechanical relations of cell-structure. 

A century since, the ideas of continuing origination 
and endless evolutionary change took on definiteness and 
clearness with the writings of Lamarck, and this has 
grown until a distinctly vitalistic and genetic view-point 
has been gained, with the inevitable rearrangement of 
perspectives and modifications of conclusions as to the 
groupings and manner of relationships among living 
things. 

Latterly, after statistical methods had reached a state 
of fair efficiency, their introduction into the study of 
occurrence, characters, distribution and form, has re- 
sulted in leading consideration from the type or the indi- 
vidual, to aggregates, or to the whole mass of individuals 

249 


250 THE AMERICAN NATURALIST [Vou. XLII 


of a group, by which amplitude of variation and mode 
of ontogenetic procedure may be accurately outlined. 

The development of this aspect of natural history has 
been followed by a truer estimation of capacities and 
activities as attributes of organisms, with the result that 
even morphology has come to be based upon physiolog- 
ical principles, upon which alone it may make further 
material progress. 

The groups with which the physiologist deals in the 
detection of activities, estimations of functions and 
measurements of performance, consist of a series of 
generations of individuals through which identical qual- 
ities, characters and capacities are transmitted uniformly 
within the limits of fluctuating variability. These 
groups may sustain the most diverse relationship and 
all possible degrees of affinity, but differ essentially in 
their physiological response to any given environment 
under permanent existence in it. 

To test such conceptions of hereditary entities implies 
pedigreed cultures, or observations upon lineal series 
under known conditions of descent, hybridization opera- 
tions and statistical estimations. The various qualities 
do not display themselves equally throughout the meta- 
meres of the sporophyte, and it is by no means to be 
assumed that the flower, or the terminal portion of the 
shoot surviving at maturity, is a compendium of the 
various developmental stages. Nowhere is this more 
beautifully apparent than in intermediate hybrids of the 
first generation, in which the qualities of one parent pre- 
dominate in the leaves and the other organs of the first, 
or lower internodes, while those displayed by the upper 
terminal portions of the stem and flowers may be those 
of the other parent. Exemplifications of this fact have 
also been observed, in which the internodes and the 
organs formed during the first season’s growth in two 
nearly related forms were widely different, displaying di- 
vergent structures and different ‘‘nasties’’ and tropisms. 
During the second year’s growth, the organs formed 


No.496] ASPECTS OF THE SPECIES QUESTION 251 


would be so nearly alike as to be in themselves inade- 
quate for the separation of the two by ordinary taxonomic 
methods. These facts, which have been illustrated more 
than once in my own cultures, are quite at variance with 
the supposition that closely related forms are most alike 
in the seedling and younger stages and most divergent 
in the members of the adult formed latest. 

Another form of transgressive variability is found 
when some descendants of individuals belonging to strain 
A, are apparently but little separated from B. Morpho- 
logically this would appear as an intergradation, but in 
reality the resembling individuals are divided and 
divisible into two groups, each carrying its own inherited 
potentialities, and in their progeny arranging themselves 
more or less symmetrically around the form of the strain, 
race or species. That the inclusion of the two is widely 
different may be illustrated in a striking manner by 
their action when crossed by a third form. 

It can not be maintained that taxonomic thought has 
accurately or quickly reflected these modern estimations: 
of the nature of living forms, for the very magnitude 
of the system necessary for the expression of relation- 
ships operates to prevent anything like a rapid or ac- 
curate adjustment. : 

Taxonomy is an eminently practical phase of botany, 
and it may reach its greatest general and total usefulness 
by confining its practise to the delineation of readily ap- 
preciable entities whether they be ‘‘natural’’ or ‘‘arti- 
ficial.’’ 

So far as investigation in genetics and in the general 
functional activities of plants is concerned, however, 
progress is to be made only by increasing precision of 
measurement, and refined exactness of method of estima- 
tion of the qualities and characters concerned in the 
activities of the organism in both heredity and functional 
performance. The realization of this requirement comes 
but slowly. There are writers who still insist that the 
intricate pattern woven by the plant during its ontogeny, 


252 THE AMERICAN NATURALIST [Vou. XLII 


as determined by micrometric measurements, develop- 
mental observations, experimental tests and statistical 
estimations upon the aggregate of the group, shall be 
capable of demonstrations by the foot rule and hand lens 
applied to the apical structures exhibited by a single in- 
dividual of the mature sporophyte, as if the pedometer 
and hand compass were adequate for testing the results 
of a triangulation made by the transit and steel tape. 
In other words, botanists of academic habit will with the 
greatest gravity attempt to read out of existence, and 
estimate of no importance, hereditary groups of organ- 
isms unless they conform to certain illy defined arbitrary 
standards. 

Taxonomic thought rounds its broadest conceptions 
when its conclusions are based upon the aggregate of 
individuals within natural groups, and embody onto- 
genetic procedure, environmental relations, heredity, 
. evolutionary change and comparative functional per- 
formance. So organized it might rightly lay claim to 
-being ‘‘philosophical botany,” and would include an 
orderly arrangement of all knowledge of plants, and 
would form the basis upon which all researches might 
be founded. 

Taxonomic practise is quite another matter; hampered 
as it is by an outworn and medieval method of giving 
names to living organisms, it is doubtful as to how far 
we might demand of it that it discriminate among the 
many degrees of relationship which reveal themselves 
in capacities and performance as well as in refinements 
of form. The more thoroughly and accurately however, 
that it takes into account the total sum of the attributes, 
qualities and capacities of the plant, the greater will be 
the value of its conclusions, and the greater will be the 
service it may render to coordinate branches of botanical 
science. 


AN ECOLOGIC VIEW OF THE SPECIES 
CONCEPTION 


PROFESSOR FREDERIC E. CLEMENTS 


UNIVERSITY OF MINNESOTA 
I. Past AND PRESENT PRACTISE IN SPECIES-MAKING 


THE species may be either a means or an end; prop- 
erly it is both. In descriptive botany, these two uses 
of the species have often been confused. The describing 
of new species has come to be recognized as an end in 
itself, while it should be nothing more than a necessary 
preliminary to further and more important botanical 
study. The interest of the ecologist in the proper recog- 
nition and naming of species is necessarily greater than 
that of nearly all other botanists. To him species are 
an indispensable means in the study of vegetation. On 
the other hand, the search for the definite results of 
adaptation and evolution, which is his final work, leads 
him inevitably to the species as an end. It is this double 
significance of the species for the ecologist that makes 
him peculiarly concerned about its treatment. So long 
as he uses the species only as a means, he is not greatly 
confused, except as a consequence of the fact that species 
are habitually made in the herbarium upon a small num- 
ber of specimens, while he meets them as hundreds and 
thousands of variable individuals. His serious troubles 
begin with experimental work in adaptation and evolu- 
tion. It quickly becomes evident that species so-called 
are widely different in rank, origin and relationship. 
Some are clearly species in the usual sense, while others 
are merely variations and forms of these. The ecologist 
thus comes to look with doubt upon all species. He 
accepts them reluctantly and provisionally until they 
meet successfully the test of experiment. 

253 


254 THE AMERICAN NATURALIST [Vou Site 


Even a casual survey of the practises in species- 
making during a century or more shows little or no 
uniformity of criteria or results. <A comparison of 
methods in the different plant groups is even more stri- 
king. This lack of uniformity is found not only in the 
work of botanists in general, but even in the work of 
the same botanist. The consequences in the form of 
unequal and invalid species have been almost innumer- 
able. This is particularly true of the fungi. To one 
familiar with them, it seems certain that the number of 
valid species is considerably less than half the number 
published. Attempts to guide the descriptive botanists 
and to make species more definite and uniform have not 
been wanting. A few of these have been noted, in order 
to show how little effect they had, even upon their own 
authors, and how utterly impossible of application they 
are without the test of experiment. 

The criteria proposed by Ray were permanence of 
form and appearance, and non-fertility with other species. 
This appears to be little more than an attempt to justify 
the practise prevalent under the dogma of special crea- 
tion. Mere observation could give little support to either 
criterion, and the thought of experimental support was 
searcely dreamed of. As a pioneer in evolution, La- 
marck gave a definition of the species, which would be 
expected to warrant more than passing interest. He 
defined a species as a ‘‘collection of similar individuals 
which are perpetuated in the same conditions as long 
as their environment is not changed sufficiently to bring 
about variation in their habits, their character or their 
form.” It is clear that the whole value of this definition 
depends upon the significance given to the word varia- 
tion. Lamarck, in his strong feeling for adaptation, hit 
upon the two essential facts, environment and variation, 
but his application of these criteria was purely academic. 

It is a significant fact that Darwin should have written 
the ‘‘ Origin of Species” without pointing out just what 
he meant by a species. His task was to prove origin 


No. 496] ASPECTS OF THE SPECIES QUESTION 255 


by descent as opposed to origin by special creation. For 
this purpose, it was unnecessary as well as impossible 
to define a species or to discover the method by which 
it originates. Darwin regularly used the terms species, 
subspecies and variety, but he did not draw a definite and 
constant line between them. De Vries has taken the 
first definite step in advance by the use of experiment 
to determine a species. It remains to be seen whether 
his concept of elementary species will clarify or confuse. 
It can not be accepted even provisionally until much 
more experimental work has been done. 

In the last decade or two, conservative American botan- 
ists have often expressed the view that proper specific 
characters can be drawn only from the flower and fruit, 
or from the reproductive parts, whatever they may be. 
Since this has sometimes been said to have been Dr. 
Gray’s view also, it seemed that it would be both profit- 
able and interesting to compare the criteria of conserva- 
tive and radical describers of species in the same family 
and genus. Time was lacking for a thorough and com- 
plete comparison, but in the few families selected the re- 
sults seem representative. It was quickly seen that 
many current species accepted by all were not based upon 
reproductive characters, and that some of the most doubt- 
ful of recent ones were. It further appeared that, while 
habit, leaf, stem, ete., played slightly more important 
parts’ in later work, there was little essential difference 
in the kind of criteria used. The striking difference lay 
in the fact that the new species segregated are based upon 
much smaller variations of the parts concerned, as a 
rule, and are consequently much more difficult to distin- 
guish when represented by many individuals. 

The ecologist finds it a necessity to be able to distin- 
guish and to refer to any difference represented by a 
number of individuals. A form or a variation is just 
as important to him as a species, and often presents a 
better point of attack. He must consequently be partly in 
Sympathy with the present tendency of descriptive bot- 


256 THE AMERICAN NATURALIST [ Vou. XLII 


any to search out and describe all groups that are dif- 
ferent, regardless of the degree of difference. He must, 
however, know the relationship of these groups, i. e., 
whether they are coordinate species, forms or what not. 
To publish them all as binomials regardless of their rank 
completely hides their relationship to species already in 
existence. It is easy to understand that this has resulted 
partly from the fact that a trinomial is longer and hence 
less convenient than a binomial. Convenience is much 
less essential than accuracy and clearness, and must 
eventually yield to permit the regular use of the trinomial 
to designate the various differentiations of a species. 
The treatment of all groups below the genus as essen- 
tially coordinate is due even more to the fact that ques- 
tions of ancestry and of origin enter all too rarely into 
the making of new species. These are questions that 
ean be settled only by the most extensive and intensive 
field work, followed by thorough experiment. For such 
work there has as yet been almost no time or sympathy, 
as is shown by the all but hopeless mélange of so-called 
new species. 


II. Bases ror DISTINGUISHING SPECIES 


The universal basis for distinguishing species has been 
the degree of morphologic difference. Physiologic and 
ecologic differences have but rarely been taken into ac- 
count, except in such groups as the bacteria. The mor- 
phologic treatment is based upon the fundamental fact 
that stable structures are’ancestral, and plastic ones de- 
rived. This has led to the basic principle that repro- 
ductive characters are of greater worth than vegetative 
ones. With this the ecologist is in full accord theoret- 
ically, but he would wish to have experimental evidence 
before accepting it as universally true. In fact some of 
the little evidence at present available indicates that this 
rule must permit some exceptions. It must constantly - 
be borne in mind, especially by those who believe that 
evolution is always a question of the germ-plasm, that 


No. 496] ASPECTS OF THE SPECIES QUESTION 257 


vegetative features alone are present in the blue-green 
alge and many of the fungi. It is evident that the 
method of morphologic differences greatly facilitates the 
provisional cataloguing of a flora, but it suffers from 
a universal and serious fault. This is the use of a few 
herbarium specimens in lieu of a large number of field 
individuals. Practically every collector selects a few 
individuals that appear typical, while for the purpose of 
scientific species-making he should collect as complete a 
series as possible of divergent individuals. Even if this 
were done, the ecologist must continue to regard the 
method as a mere preliminary, which serves to arrange 
the material and hence to facilitate the real study of 
species. 

Closely connected with morphologic difference is the 
question of the absence of intermediate forms. This 
appears to have played a more important part in zoology 
than in botany. In the latter case, at least, it seems 
often to have been taken for granted as a necessary con- 
sequence of structural differences. . At best, it has regu- 
larly been a question of intermediate forms in the her- 
baria and not in the field. 

Constancy as a eriterion of species is also but another 
phase of morphologie difference. As such it seems to 
have been used chiefly to designate uniformity of differ- 
ence throughout the individuals concerned. The con- 
stancy of a structure from one generation to another, or 
from one habitat to another has been given little atten- 
tion in species-making. Yet it is precisely these which 
are of fundamental importance. This fact, however, 
makes it at once evident that constancy is something that 
can only be determined by combining the most extensive 
field observations year after year with experiments in 
various habitats. This makes it clear that our present 
knowledge of constancy is almost purely theoretical, and 
that it is profitless to discuss it in our present ignorance 
of it. 

To the ecologist, then, the usual bases for distinguish- 


258 THE AMERICAN NATURALIST [ Vou. XLII 


ing species, viz., degree of morphologic difference, ab- 
sence of intermediate forms, and constancy, are entirely 
inadequate. He sees three critical facts in the develop- 
ment of a new species or any new form: (1) ancestry, 
(2) habitat or method of origin, (3) structural changes, 
very rarely functional ones. None of these can be studied 
adequately anywhere but on the ground. ‘The first two 
are purely experimental questions. While the most thor- 
ough field study is a necessary preparation for them, 
they can never be decided except by experimental 
methods in the field. Apart from the study of the origin 
and structure of vegetation, the fundamental task of the 
ecologist is the experimental investigation of the origin 
of new forms, the so-called species. 


IT. Ecoitocic PROCEDURE 


The questions of what a species is, what are species 
and what are not, and of the origin of species and of 
forms must then be decided by experiment. The method 
of attack is easily determined, but the procedure is super- 
latively slow and laborious, and the demand upon time 
and patience unlimited. In spite of his inclination, the 
ecologist finds it necessary to accept as a working basis 
the species at present distinguished. His first task is to 
discover those that seem to give the best promise of re- 
sults under experiment. The procedure consists of two 
essential processes: (1) field observations throughout the 
habitat of the species concerned and (2) experiment. The 
latter is the crux of the whole question. It consists of 
three steps: (1) the exact measurement by instruments 
of the original habitat and the new one, (2) the experi- 
ment itself and (3) the measurement of results, 7. e., the 
determination of the degree of morphologic and histo- 
logic difference. The detailed procedure in each of these 
has been given in ‘‘ Research Methods in Eeology’” and it 
is unnecessary to repeat it here. It is sufficient to indi- 
cate that experiment should proceed whenever possible 

* Research Methods in Eeology, 25, 145. 


No. 496] ASPECTS OF THE SPECIES QUESTION 259 


along three parallel lines, which have been designated 
as (1) natural experiments, where advantage is taken 
of natural movement into new habitats, (2) habitat cul- 
tures, where reciprocal plantings are made in original 
and new habitats, and (3) control culturés, where the 
experiments are carried on in plant-houses, where they 
can be controlled and directed at will. In addition to 
this, definite experiments for the determination and pro- 
duction of constancy are of fundamental value. In 
regard to the evaluation of the new form when once 
produced, it will suffice here to state that this should be 
concerned both with the individual and with the group 
of individuals. The proper determination of the latter 
is the task of biometry, when it has attained the neces- 
sary development. 

For the preservation of the results. obtained by the 
ecologic methods briefly sketched above, an evolution 
herbarium is proposed. It is felt that the usual taxo- 
nomic herbarium will have its usefulness restricted more 
and more to the preservation of types, and to the pur- 
poses of instruction. The evolution herbarium will be 
the record of field observations and experimental results. 
A species or a form will be represented in it by all the 
variations that can be discovered, and each variation by 
a large number of individuals. The new forms produced 
by nature, and by experiment in nature or under control, 
will likewise be adequately represented. This repre- 
sentation will take the form not only of the usual dried 
specimen, but of photographs, drawings, slides, pre- 
served material, ete. With all this, however, the evolu- 
tion herbarium is still to be regarded as a record merely. 
It is not to replace the taxonomic herbarium as a mass 
of working material to be shuffled about and made into 
species. It is a repository of species and forms when 
they have finally been determined by experiment. 


260 THE AMERICAN NATURALIST [ Vou. XLII 


IV. NOMENCLATURE AND TREATMENT OF New Forms 

Enough has been said to indicate clearly the ecologist’s 
view of species, both valid and otherwise. He is vitally 
interested in the species’ ancestry, its method of origin 
and the factor concerned, as well as in the result, which 
is the species or form itself. Until his experimental 
study of these points makes it possible to distinguish 
species from minor groups, or shows that the species 
concept is a mistaken one, it is useless to debate whether 
the resulting form is a species or not. In fact, the status 
of the result must await the determination of ancestry 
and origin in every case, and we may well call all the 
results forms until this has been done for each. 

The question of ancestry resolves itself at the outset 
into one of old forms or of forms newly produced. The 
production of a new form from an old or existing one 
by properly checked experiment at once gives the an- 
cestry of the former. Here, where the whole experiment 
is under our control from beginning to end, we may con- 
centrate our attention upon the method of origin and 
the factor concerned. The discovery of the ancestor of 
an existing form or species is often a much more difficult 
matter. Until the ancestry is determined, it is useless 
to try to ascertain the method of origin, and the factor. 
When the form bears the distinct stamp of sun or shade, 
of a wet or dry habitat, or of hybridation, etc., our search 
is narrowed at once to deciding what species gives the 
most promise of being the parent form. When there is 
no distinct stamp, we must first look for the most promis- 
ing species, and then try the various methods and factors 
experimentally until the form sought is produced. How 
often the ancestry and origin of accepted species can 
be worked out in this way remains to be seen. Results 
already obtained show that this method works perfectly 
in the few cases tried, and that it may be expected to 
prove successful in many cases. When a complete series 
of trials of suspected parents does not give the form 
sought, it seems fair to assume that these and the species 


No. 496] ASPECTS OF THE SPECIES QUESTION 261 


sought are more or less coordinate. In this process, it is 
probable also that light will be thrown on the question 
of their derivation from a common stock or from two 
or more stocks. 

The four methods by which new forms originate have 
been discussed before this society in a paper read last 
year. These have also been given in some detail in print® 
and are so generally well known to botanists that de- 
tailed consideration of them is-unnecessary here. ‘These 
four methods are adaptation, mutation, variation and 
hybridation. Variation alone has not yet been certainly 
established by experiment as a method by which new 
forms originate, but the evidence of it is so strong that 
it amounts to presumptive proof. It seems certain that 
for plants at least it is not the principal method, as 
Darwin thought, and that it is probably much less im- 
portant than adaptation, and probably also less impor- 
tant than mutation. It is, however, a much more obscure 
process, and it is impossible to tell in the absence of any 
critical experiments just what it is, or what its impor- 
tance may’ be. Darwin has said: ‘‘I have spoken of 
variations sometimes as if they were due to chance. This 
is a wholly incorrect expression. It merely serves to 
acknowledge plainly our ignorance of the cause of each 
particular variation.’?’ The exact measurement of 
habitats has made it clear that minute variation in the 
factors of the habitat is a very important if not the ruling 
cause in the production of minute variations in structure. 
In the case of the minute initial variations shown by the 
individuals of a group, it is impossible to tell at present 
how much is due to heredity and how much to causal 
variation of the habitat. It seems probable that the 
former may control in some forms, and the latter in 
others. Furthermore, while hybridation stands apart 
sharply from the others as a process in which existing 
characters are mixed in some degree, it is becoming more 
and more probable that adaptation, variation and muta- 

2 Research Methods in Ecology, 147 ; Plant Physiology and Ecology, 185. 


262 THE AMERICAN NATURALIST [ Vou. XLII 


tion are only different phases, perhaps merely differ- 
ences in degree, of the fundamental struggle between 
heredity and environment. 

Forms arising by adaptation have been called ecads, 
those from variation, variants, and those from mutation, 
mutants. With the familiar term hybrid for the pro- 
duct of hybridation, we are able to designate in a 
general way the forms originating by the four methods. 
The ecologist, and sooner or later the whole botanical 
world, must have some definite way of naming each par- 
ticular form. It is possible to take no further thought 
about the matter, and allow this nomenclature to grow 
in the same random, unscientific fashion that nomencla- 
ture has always grown. It seems highly desirable, how- 
ever, to consider the requirements of the case, and make 
suggestions as to the best method of meeting them. The 
first essentials of a name are that it should be as short 
and as significant as possible. For our present purpose, 
the name of each form should indicate the ancestry and 
the method of origin, and, when it is known, the causal 
factor. Many ways of securing this result have been 
considered for each method of origin. This may be illus- 
trated by the following list, showing several possible 
ways of naming the shade ecad of Galium boreale. 
Galium dubiosum n. sp. : 

Galium boreale dubiosum. 
Galium boreale. 

Galium borealades. 
Galium boreale scias. 

The first method, which is that of descriptive botany 
at present, indicates nothing of ancestry, origin or factor. 
The second gives merely the ancestry, as does the third. 
The fourth gives both ancestry and method of origin, 
the patronymic suffix -ades referring to ecad. The use 
of a suffix has much to commend it, particularly the fact 
that it makes it possible to designate the forms of a 
species by means of a binomial. Its use, however, has 
practically been made impossible by the senseless names 


Se e N 


No. 496] ASPECTS OF THE SPECIES QUESTION 263 


that have too often been given species. The fifth method, 
though requiring the use of the trinomial, is the best. 
It has all the brevity possible, and yet indicates ancestor, 
method of origin and factor concerned. It is interesting 
to note that this problem was worked out in 1902 in essen- 
tially the same fashion.? The shade form of Galium 
boreale was then called Galium boreale hylocolum. The 
present method has the advantage of brevity, and of 
referring directly to the causal factor concerned in pro- 
ducing the ecad rather than to the habitat as a whole. It 
is a relatively simple matter to recognize and produce 
sun and shade ecads, wet and dry ecads, but ecologic 
analysis can hardly go further at present. Consequently, 
the use of scias, helias, xeras and hydras, denoting re- 
spectively shade form, sun form, dry form and wet form, 
will not only enable us to designate all new ecads briefly 
and conveniently, but it will also reveal the ancestor, 
method of origin and causal factor at a glance. 

After much puzzling, it seems that it will prove diffi- 
cult, if not impossible to improve upon the conventional 
method of designating hybrids, viz., Galium boreale X 
trifidum. Until more is known of variants, it is proposed 
to designate them by a brief and applicable trinomial 
term, e. g., Galium boreale exiguum. While this is the 
usual trinomial, it would at once reveal the method of 
origin, as well as the ancestor, by virtue of the fact that the 
other three methods of origin have their proper trinomial 
form. In our present knowledge of mutants, it seems 
impossible to take the cause into account. The sugges- 
tion is accordingly made that the mutant be named with 
reference to its most striking characteristic, the trinomial 
term to bear the prefix per, very, referring to the salta- 
tory nature of mutation, and thus denoting the method 
of origin. The value of these suggestions may be indi- 
cated by comparing the trinomials thus formed with the 
corresponding binomials. 


3 Herbaria Formationum Coloradensium. 


264 THE AMERICAN NATURALIST [ Vou. XLII 


Cerastium oreophilum == Cerastium strictum scias: eead. 

Verbena intermedia = Verbena stricta X hastata: hybrid. 

Aquilegia jamesii = Aquilegia cærulea peralba: mutant. 

Macheranthera aspera = Macheranthera viscosa aspera: variant. 

In concluding, the ecologist will confess frankly that 
he does not know what a species is. .On the other hand, 
he is certain that he knows some of the things it is not, 
and that the species of the descriptive botanist comprise 
several widely different things. Just what these are and 
what their relation to species, if there are such, is a 
matter to be decided by experiment alone. The ques- 
tion of what a species is can not even be answered pro- 
visionally until a sufficiently large number of experi- 
ments have been made to indicate the regular procedure 
in the origin of plant forms and to reveal the principles 
that control it. 


AN ECOLOGICAL ASPECT OF THE CONCEPTION 
OF SPECIES 


DR. H. C. COWLES 


UNIVERSITY OF CHICAGO 


Is the discussion of this question I do not feel myself 
hedged in by any limitations, since no one pretends to 
say what are the bounds of ecology. Indeed, to define 
a species may be regarded as an easy task, compared 
with the task of one who sets out to define ecology. And 
so this occasion affords me a pleasant opportunity to 
present some views for which I have long desired an 
audience like this. 

It is coming to be realized that the problems of physiol- 
ogy and ecology are essentially identical, not alone in 
the matter of the species concept, but in all respects. 
Physiologists and ecologists have come to feel that the 
experimental method furnishes the only adequate test 
for determining the validity of species. The method of 
approach has differed with the point of view, and it is 
the physiologist who has given most emphasis to the 
fundamental importance of experimentation. The ecol- 
ogist, on the other hand, has brought in the rich contribu- 
tions of field observation. It is only recently that each 
has recognized the imperative necessity of the method 
of the other, and it now seems possible to predict that the 
fundamental method of the future is to be field experi- 
mentation combined with observation. No one realizes 
so well as does the ecologist the inadequacy of laboratory 
experimentation in the settlement of field problems. The 
ecologist feels that the species problem is essentially a 
field problem, and hence incapable of final settlement, 
either in the herbarium or in the laboratory. Yet it is 
the exact methods of the laboratory carried into the 

5 


Ead 


266 THE AMERICAN NATURALIST [Vou. XLII 


field that give promise of the solution of the problem of 
species. 

Perhaps no phenomena bring the principles just 
enunciated into more clear relief than do those of natural 
selection. Many species must be born that never have 
an opportunity to survive, owing to their lack of adapta- 
tion to the surroundings in which they originate. The 
mutants of (nothera lamarckiana, though developed 
under essentially similar conditions, do not appear 
equally adapted to the environment in which they first 
appeared; had they been left to themselves, some mutants 
would have perished, while others (and perhaps espe- 
cially Œnothera gigas) might have lived. The citrus 
hybrids, developed in government experiments in Florida, 
form another group of new forms, some of which are 
best adapted to one climate, and others to another. Since, 
therefore, no necessary adaptive relation must exist be- 
tween a new species and the region of its birth, it is clear 
that the laws of selection determine the success or failure 
of new species. The interpretation of selection is a field 
problem, an ecological problem. A theoretical plant 
species may be produced in the laboratory, but the real 
species that make up the vegetation of the world are de- 
veloped and must be studied out of doors. 

One of the noblest aims of ecology is the destruction 
of many of the ‘‘species’’ of our manuals. Where the 
critical study of species is confined to the herbarium, it 
often happens that ecological varieties or habitat forms 
are given specific rank. An excellent instance of this 
is seen in the case of Polygonum amphibium and P. 
hartwrightii. The latter, which looks wonderfully dif- 
ferent from the former in herbaria, can be developed at 
will by growing P. amphibium on land instead of in the 
water. Not infrequently a plant may be found on the 
edge of a pond, showing branches in the water that would 
commonly be referred to P. amphibiwm, and aerial 
branches that would be regarded as P. hartwrightii. 
Bonnier’s classic experiments, whereby many alpine 


No. 496] ASPECTS OF THE SPECIES QUESTION 267 


plants were shown to be capable of being developed into 
well-known lowland species in a single generation, illus- 
trate a phenomenon similar to that exhibited by Poly- 
gonum. It is likely that our manuals contain many so- 
called species, such as these, which await reference to 
ecological varieties. 

Having eliminated habitat forms from the rank of 
species, and having disposed of the influence of natural 
selection as a destroyer of many incipient species, it 
remains to discuss the varied ideas concerning the real 
or supposed species that remain. In the main it may 
be said that there are two opposing conceptions of 
species that are to-day struggling for mastery in the 
realm of biologic thought. The more prevalent idea, 
dating in its essence from the time of Darwin, has been 
that species are artificial creations, mere matters of con- . 
venience in the classification of the organic world, arbi- 
trary concepts that have no great and enduring reality. 
Partisans of this view hold to the doctrine of continuity, 
maintaining that all species have been connected with 
other species by a series of intergrades, and that there is 
no vital distinction between variation and mutation. If, 
indeed, many species, such as the sassafras, differ widely 
from all other known species, this is because of the elimi- 
nation of intergrading forms. In the case of Sassafras, 
this idea is strengthened by the evidence furnished by 
fossil forms. In somewhat striking contrast to this con- 
cept of species stands the idea that species are entities, 
which arise by discontinuous variation or mutation, and 
which have their full specific value from the start. Nor 
does time change specific form by any slow gradations; 
the species at its’ death shows no essential difference 
from the species at its birth. In many instances, at least, 
these species are of lower rank than the Linnean species, 
and have been known as small or elementary species. As 
a rule those who hold to the latter species conception are 
more prone to appeal to hidden ‘‘internal’’ causes in 
explaining the origin of new species, while environmental 


268 = "THE AMERICAN NATURALIST [ Vou. XLII 


factors in evolution are more commonly held as dominant 
by those who regard species as indefinite things gradually 
evolved from other species. In this connection it is 
curious to note that the idea of a species as an entity, 
now held by most mutationists, has much in common 
with pre-Darwinian notions of special creation; it seems 
to'be in part a return to former conceptions of a rigid 
nature. On the other hand a new idea of species content 
is set up. Both pre-Darwinians and Darwinians agreed 
that Draba verna is a species, but the new school would 
maintain that under this name are masquerading a hun- 
dred odd real species. 

There are, then, two radically different conceptions of 
species now current, one of a rank as much higher than 
the other as the genus is above the Linnean species, or 
the family above the genus. Ecological observations 
support both views, but it is especially the experimental 
method that has made things clear. Whether or not 
one calls them species, it is evident that the genus 
(Knothera contains a number of entities, sharply defined 
from one another. In such genera as Salix and Aster 
there is reason to believe that species do not thus differ 
sharply, but that they are connected with one another by 
all but imperceptible gradations; at any rate this condi- 
tion exists in Leptinotarsa, as conclusively shown by 
Tower. It seems impossible to homologize species in 
(Œnothera and Leptinotarsa. It appears that the method 
of evolution in various groups of plants and animals is 
radically different, and it follows as a corollary that 
what are called species in these various groups are neces- 
sarily not homologous. 

In the light of these views the task of the taxonomist 
is seen to be most difficult; for the convenience of biol- 
ogists, he must reduce to common terms things that are 
unrelated; he must homologize things that are not homol- 
ogous. In such a dilemma there seem two courses open: 
(1) The Linnean species concept, that has ruled both 
before and after evolution was accepted by biologists, 


No. 496] ASPECTS OF THE SPECIES QUESTION 269 


may be abandoned. ‘The elementary species then be- 
comes the species of taxonomy. Something akin to this 
has already taken place in certain genera, notably 
Crategus, Viola and Sisyrinchium. Those who take this 
attitude should abandon the year 1753 as a starting point 
for specific nomenclature, since a new conception of 
species demands a new datum line. Possibly this datum 
line is furnished by the experimental work of Jordan on 
Draba verna. Such a revolution would of course be ap- 
palling in its consequences. The present status of 
Crategus, perhaps, gives an index of what is to come, 
if this idea is accepted; where now we have dozens of 
species, we may expect hundreds or even thousands. 
We may even expect the appearance of a taxonomic daily 
newspaper with its hourly record of new species and 
their fluctuations, comparable with market quotations in 
a period of financial panic. (2) The alternative is to 
retain the Linnean species concept as a working theory, 
employing trinomials for elementary species. Thus we 
should speak of Ginothera lamarckiana rubrinervis, O. 
lamarckiana gigas, ete. One great advantage of follow- 
ing this method would be that we should secure all the 
advantages of the newer critical study of such genera as 
Crategus and Sisyrinchium, and at the same time tie the 
new work to the old in such a way that those not taxono- 
mists could appreciate the general significance of the re- 
sults. Very few except Crategus specialists could tell 
offhand anything about Crategus ellwangeriana or C. 
champlainensis, but if these forms were denominated 
respectively, C. mollis ellwangeriana, and C. mollis 
champlainensis, many would know their general affinities, 
In the case of intergrading species without well-defined 
specific boundaries, the only course is to retain the tri- 
nomial for varieties, much as has been done in the past. 
If it is wished to distinguish between varieties and ele- 
mentary species, the expression var. might precede the 
varietal name, as is the custom now with many. 7 
It is to be hoped that the taxonomists, and particularly 


270 THE AMERICAN NATURALIST [ Vou. XLII 


- those taxonomists who have sinned in the much making 
of species and those who have made a so-called critical 
study of plants without any adequate training in the 
general principles of botany, will reform their ways. 
In truth, they must reform. No longer may each man 
be a law unto himself. Nor is it right that any group 
or coterie should make rules and regulations that run 
counter to the expressed opinions of a world botanical 
congress. It is doubtful if any single botanist agrees 
with all of the taxonomic expressions of the Vienna Con- 
gress; it is even possible that some agree with none of 
its provisions. However, it registers a general consensus 
of opinion, agreed upon by those who thought the con- 
gress far too radical, and by those who thought it far 
too conservative. It marks a step in the taxonomic 
progress of the botanical world, and there is no surer 
way to lead toward further progress than in abiding by 
its provisions; on the other hand, there is no surer way 
of ensuring the continuation of the taxonomic chaos, of 
which we have had far too much, than in setting up indi- 
vidual or even provincial or national codes in opposition 
to a world code. An American school of taxonomy is 
an anomaly, since many species are world-wide, and 
should have world-wide names; even the local species 
should be delimited in accordance with international 
rules. 

Taxonomy must be scientific. It must require for its 
devotees a training as rigid as that required by profes- 
sional workers in morphology, physiology or ecology. 
Species-making by taxonomic tyros must be abandoned. 
The requirement of Latin diagnoses, though regretted 
by many of us, may be of help in checking the voluminous 
contributions of amateurs. In the future it must be 
recognized that the final test of the validity of species 
is experimental, and taxonomists must work no less in 
the herbarium, but more in the field and in the garden. 
If the taxonomists of the future fail in these respects, 
a hard but certain fate awaits them. The world of 


No. 496] ASPECTS OF THE SPECIES QUESTION 271 


morphologists, physiologists and ecologists has borne. 
with them patiently and long, and, has deferentially 
abided by the specific determinations of the taxonomists. 
The recent ebullitions of the taxonomic radicals have 
evoked in botanists in general successively dissatisfac- 
tion, contempt and rage. These things will not be en- 
dured much longer; a little more and the sinning taxon- 
omists will be ‘‘east out into the outer darkness where 
there shall be wailing and gnashing of teeth.’’ 


DISCUSSION OF THE SPECIES QUESTION. 


At THE close of Mr. Cowles’s paper the chairman in- 
vited those present to discuss the question. The follow- 
ing remarks were made: 

Mr. J. M. Covutrer: I find myself in some particulars 
agreeing with every speaker, and it seems to me that 
there are enough elements in common in all that has been 
said to enable us to reach some sort of working basis. 
One thing agreed upon in all that has been said is that 
nature makes individuals and men make species. This 
means that in a certain large sense the individual is the 
unit to be recognized. At the same time it is evident 
that the attempt to record such units on the basis of any 
present scheme is entirely out of the question. While 
it is clear that we are approaching greater uniformity 
in our conception of species, we shall not reach agree- 
ment until we know more definitely the influence of 
ecological and physiological factors, if we may separate 
them for the moment, upon structures. But until this 
knowledge becomes more exact, how shall records be 
made? We must have some temporary and effective 
method. We all appear to recognize the fact that the 
indefinite multiplication of names of species must be 
stopped sooner or later, and the sooner the better; for 
we are getting the record into a condition that makes it 
unworkable. It seems to be the belief of every speaker 
that something must be done, and that the conception of 
a species must be modified eventually. It is quite evi- 
dent that we are in no position as yet to formulate 
definitely what we shall agree to call a species, and in 
the meantime it seems to me the suggestion made by Dr. 
Britton is a very workable one. It gives to every one 
the opportunity to distinguish and record forms clear 
down to individuals if he chooses; and at the same time 

272 


No.496] ASPECTS OF THE SPECIES QUESTION ~— 278 


it removes the grievous burden of a great multiplication 
of names. It seems to me that the suggestions of Dr. 
Bessey and Dr. Britton almost meet at this point. In 
effect, it means to continue to name easily recognized 
forms, calling them species if desired; and then by a 
system of numbers to indicate the more refined distine- 
tions. This avoids the great multiplication of names 
and secures an exact record. This method has been 
developed so effectively in the cataloguing of stars and 
books that it could be adapted for plants without serious 
trouble. I would ask Dr. Britton how much this scheme 
would reduce the number of published names. 

Mr. N. L. Brrrron: I do not know. . Those that have 
been published up to this time it would reduce probably 
two thirds. 

Mr. J. M. Couurer: A reduction of the names to one 
third would be a good start, and I think we had better 
hold Dr. Britton to his idea. I think we can get together 
on this suggestion, so that all botanists can recognize the 
ordinary forms and remember their names, and the taxon- 
omists can record the more refined distinctions. I had 
not heard of this proposition before, but at present it 
appears to me to be desirable and workable. 

Mr. J. B. Potuock: I should like to say a word along 
the line of work upon which Dr. Arthur has presented 
some thoughts to you, but I think we can go a little fur- 
ther than Dr. Arthur did in his argument in regard to a 
definite method of getting at species from the physiolog- 
ical basis, and the people who are nearly ready to begin 
that, I feel sure, are those who have worked with the 
fungi from the cultural side. In talking with a number 
of men, who are interested in that side of the work, in 
the course of these meetings, I have been impressed with 
a fact the importance of which has been growing upon 
me in my work alone, that the men who are doing that 
kind of work are feeling the absolute necessity of doing 
something definite exactly along the line which has been 
indicated by almost all the speakers here in a general 


274 THE AMERICAN NATURALIST [ Vou. XLII 


way. Now, what I mean is the kind of work which was 
reported in the botanical session this morning on 
Penicillium and its relation to definite culture media, 
and I believe in the very near future we shall be describ- 
ing species, of many of these fungi in a definite relation 
to culture media. <A species will be a group of those 
organisms which show a certain combination of morpho- 
logical characters when grown upon a medium of definite 
and known composition. The type of the species in- 
volves a type medium, and the fluctuating variations 
must be determined by the use of a series of such media. 
Considerable work in this direction has been done, but 
the method has not yet been well adapted to taxonomic 
description. I think we are ready now to do this work 
from a strictly taxonomic point of view. That will be 
doing exactly what at least four of the speakers have 
advocated, but they did not tell us in detail how to do it. 
These fungi are particularly suited to this kind of work 
for several reasons. In the first place, they are small 
in size and we do not need a garden in which to grow 
them; we can grow them in a test-tube. In the second 
place, they reproduce exceedingly rapidly and we do not 
have to wait a year or ten years in order to get them to 
produce new generations. They may do that in a few 
hours, or at most in a few days, so that we can produce 
generation after generation, while the man who is work- 
ing with flowering plants is waiting for one generation 
to develop. Hence these plants are favorable material 
with which to begin the kind of work which seems to be 
demanded, namely, the union of the morphological and 
physiological factors in the description and delimitation 
of species. 

Mr. T. J. Burrmu: I do not know that I have anything 
very definite to say, but I am somewhat conscious of a 
feeling that I am glad that I am not a taxonomist this 
afternoon. „The taxonomist has certainly suffered this 
half day. It was said here a few moments ago that there 
had been no progress along the line of the systematist; 


s 


No. 496] ASPECTS OF THE SPECIES QUESTION 275 


that we have developed greatly elsewhere, but in this 
particular we have remained medieval or worse than 
_ that. I think we have abundant evidence right here that 
there has been progress. This meeting this afternoon 
would have been no more possible a dozen years ago 
than it is now to separate out the species of Crategus by 
somebody who has not studied them during that time. 
There has been something working. People have been 
finding that there is something besides names and dates; 
something has occurred since 1753. It looks to me as 
though it were hopeful. If there is anarchy, more of 
that than anything else, it is a pretty good beginning to 
start something that is not anarchy. 

However, I feel sure I shall not give up everything in 
regard to our common notion of species and species’ 
names. Ido hope that I shall know the white oak under 
its proper name hereafter when I see it, and a few other 
things like that; and I think it is really important that 
when we speak about certain things, of certain effects 
and relations, we do understand what we are talking 
about and that others may also understand. I think 
it does make a difference as to whether we continue the 
use—to take Dr. Arthur’s first illustration—the definite 
use of such terms as Bacillus anthracis and Bacillus 
typhosus, and the rest of them. If a writer is going to 
discuss a subject in which these organisms play a part 
and one that is vital to our existence and welfare, it is 
surely desirable that we should have a correct interpre- 
tation of what he means when he uses these terms. I 
believe we are pretty near that meaning in regard to the 
common organisms in the group of bacteria, so that we 
know pretty well what is meant when such names as 
those above are mentioned, though nobody will deny that 
included among the organisms to which the names ap- 
ply there are considerable differences. They are dif- 
ferent in their sizes, if you come down to microbe meas- 
urements; they differ certainly in their growth upon 
different media, and I do not see why the physiological 


276 THE AMERICAN NATURALIST [ Vou. XLII 


effects may not just as well enter into the species idea 
as the morphological characteristics, if we can get them; 
but I do not know how we are going to get them for such 
plants as forest trees. In the case of the white oak, we 
have got to take the morphological characteristics alone, 
so far as I see. We can not plant the seeds and witness 
the trees as they develop in their various stages until 
they produce seed again. But in case of the lower forms 
with a generation a day, we can certainly do that, and 
I think we ought to do it for specific characteristics. 

Let me say, what I am most interested in is that we 
shall know some things yet by some very well known 
names. 

Mr. E. G. Hii: As we have had considerable talk 
from the pulpit, perhaps a little experience from the pew 
in regard to species might be of use. In 1874, I came to 
that part of Illinois which is now embraced in the city of 
Chicago, and the year after I began the study of the flora 
of the region, the sand region (it was all sand then), 
particularly this dune region east of the city, and there 
has not been a year since that I have not been out there 
more or less. Now, I have not been over every foot of 
it, but with regard to this plant, the Polygonum amphib- 
ium that has been cited, I always until about 1890 or 
1895, I can not give the exact year, I always saw Poly- 
gonum amphibium, I never saw the other kind. At that 
time I noticed this hairy plant, with shorter internodes, 
growing on dryer places. The exigencies of the expand- 
ing city and manufactures outside of it led to the partial 
drainage or entire drainage of considerable areas of our 
dune flora. The underground parts of Polygonum am- 
phibium are pretty extensive. I never satisfy myself 
without digging up the entire under part of plants, or 
digging up the root—I can follow a root ten feet, if 
necessary. When those wet places were drained, the 
roots persisted in the sand, and the plants while pre- 
serving their full form when in the water, would be hairy, 
and you can trace them all the way from the water up, 


-J 


No. 496] | ASPECTS OF THE SPECIES QUESTION 27 


may-be twenty to thirty feet from the edge of the water, 
making their way even along paths or roads. Now, I 
want to say, I do not know that they did not exist before 
that, but I never noticed them until then; and not a mile 
or two miles from here, if there are vacant lots, you will 
probably find Polygonum hartwrightii in a drained 
slough, where twenty to twenty-five years ago you would 
not find anything of that kind, but you would find 
Polygonum amphibium. It seems to me that is the way 
in which it might have originated here. This experience 
extends from about 1875, and although I gather from it 
that it was not here before, I believe that it made its 
appearance not far from 1890 to 1895. 

Mr. G. H. Saux: In one sense the recent discoveries 
in the realm of variation and heredity appear to lead 
to a backward step in the concept of a species, since the 
view of the naturalness of species to which these discov- 
eries lead, resembles the earlier view. Upon a com- 
parison of the basis of this conception, however, in the 
time of Linneus, with the DERN situation, the contrast 
becomes sufficiently striking. 

At that time no cognizance was inkeri of the importance 
of variations. When variations were first fully taken 
into account, about the middle of the last century, they 
were apparently conceived to have no natural limits, and 
in consequence, no form-group could have natural limits. 

The demonstration that variations have natural limits 
has shown that the lowest grade of form-group is a 
natural group of individuals differing from each other 
only by fluctuations. It appears to me that the able dis- 
cussions to which we have listened might all be reduced 
to the question of the desirability or feasibility of looking 
upon these ultimate, natural form-groups as species. 
This question largely rests upon the question of utility, 
and herein lies our difficulty in reaching a universally 
satisfactory conception. To the maker and keeper of 
herbaria and to the field naturalist, utility requires that ` 
species shall be separable by characters which may be 


278 THE AMERICAN NATURALIST [ Vou. XLII 


recognized by a more or less careful examination of a 
single individual of unknown ancestry. To the experi- 
mentalist, whether he be a physiologist, an experimental 
morphologist or a pedigree culturist, such a conception 
of species makes them of no utility, and this is also 
largely true with students of cytology, anatomy, etc., who 
study the morphology of structures not externally visible. 
As a student of variation and heredity from the experi- 
mental side, I hold that the natural group is the only one 
that can be of any utility to any one but the herborizer, 
but I do not insist on the privilege of calling this natural 
group a species. That matter is entirely immaterial. 
To avoid confusion, we are now calling these groups 
elementary forms, but this expression is unnecessarily 
cumbersome for the constant use the conception must have 
in the future literature of botany, and I hope that some 
one will come forward with an acceptable short designa- 
tion for these, in case the herborizer succeeds in checking . 
the trend of development of the conception of species 
from an arbitrary to a natural one. 

Experimental evidence at the present time shows at 
least two grades of form-groups. These were recognized 
by Dr. De Vries under the names, elementary species 
and varieties. By ‘‘varieties’’ De Vries indicates those 
forms which differ from their nearest related form in 
one or more characteristics, which behave according to 
Mendel’s law upon crossing with it. As taxonomists 
have definitely abandoned the use of the term ‘‘variety’’ 
- to the horticulturist, we need a new word with which to 
speak of this very definite class of forms. As we have 
taken liberties with the name of Mendel in the formation 
not only of the adjective ‘‘Mendelian,’’ but also the verb 
‘‘Mendelize,’’ there seems to be no reason why we might 
not go farther and call these Mendelian varieties Mendel- 
ities. These Mendelities are hangers-on of species, and 
corresponding Mendelities may belong to many different 
species, as may be illustrated by the frequency of occur- 
rence of white-flowered or albino forms, which differ 


No. 496] ASPECTS OF THE SPECIES QUESTION 279 


from their corresponding pigmented forms in no other 
character but that of pigmentation. Whether Mendelities 
may in any case be the initial modification leading to new 
elementary species is not known, but I believe that we 
are not yet warranted in so considering it. But elemen- 
tary species and Mendelities are certainly natural entities 
and must be used as the physiological units of form. 

Mr. J. A. Harris: It seems to me that while the sys- 
tematists are receiving the congratulations of morphol- 
ogists and ecologists, it will be well for us to remember 
that he ‘‘that is without sin’? among us ‘‘should cast 
the first stone.’’ I think in the present state of biology, 
the morphologist and physiologist and ecologist have 
some points to learn from the systematist, and that the 
morphologist, physiologist and ecologist are to some ex- 
tent responsible for our present inadequate knowledge of 
species. 

The taxonomist has worked out a very careful scheme 
of recording his observations; he feels himself bound, in 
preparing a monograph, to cite all descriptions. It is 
perfectly easy to take a well-prepared monograph and to 
follow out the earlier literature of any form. If, on the 
other hand, one turns to morphological and physiological 
writing, he will find it is a difficult task to locate the work 
which others have done on the same species. It seems 
to me that if the taxonomist is expected to make use of 
experimental and ecological data in his limitation of 
species, he should be given the data, by those who are 
doing such work, in a form in which he can use them. 
Take, for instance, our ecological papers. An ecologist 
works on a certain region and refers to a number of 
species definitely, and to a larger number of species in- 
definitely, grouping them as grasses, sedges, asters, ete. 
How is the taxonomist to utilize such data. The work 
of the ecologist should be specific and comparative. He 
should be explicit in his statements concerning the form 
and life conditions of a species in his own region, and 
he should refer to the literature in such a detailed fashion 


280 THE AMERICAN NATURALIST [ Vou. XLII 


as will enable the systematist to determine the character- 
istics and the environment of the same species in another 
region. I think the morphologist, too, must adopt the 
practise which the systematist has found indispensable. 
He should cite in a clear but condensed form all the 
pertinent morphological literature for each of the species 
which he treats. The recognition of this obligation 
would, I believe, do much to raise the standard of our 
published work, and it would place at the disposal of the 
systematist a mass of data which he ought to use to great 
advantage. 3 

Mr. A. E. Hircxcocx: I wish to call the attention of 
the ecologists to one very important method by which they 
may greatly aid the taxonomists. The former are doing 
much careful work in studying the ecological relation- 
ships of plants, but in order that this work may be 
checked up and be available to taxonomists it is necessary 
that specimens of the species studied should be prepared 
and deposited in a public herbarium. Unless such a 
permanent record can be made the statements concerning 
habitat, variation and other ecological data are of little 
value to the systematist, because they can not be verified. 
Such verification is especially necessary because the ecol- 
ogist is not likely to be sufficiently familiar with all 
groups of plants to pass authoritatively upon their botan- 
ical names. Even when the plants are submitted to 
taxonomists for identification it may happen that errors 
occur. Data based upon specimens available in public 
herbaria would aid ecologists themselves to coordinate 
their work. Taxonomists will be glad to avail them- 
selves of all serious work done by ecologists when the 
data can be definitely connected with preserved specimens. 

One other point. I wish to emphasize the necessity of 
field work in determining the limits of species. If pos- 
sible, taxonomists who are monographing groups of 
plants should study these plants in the field. The 
botanist can determine usually to his own satisfaction 
the limits of variation of a single species in a given 


No. 496] ASPECTS OF THE SPECIES QUESTION 281 


locality. The herbarium then becomes a record of his 
field observations. Much good work can be done in the 
herbarium, but when coordinated by abundant observa- 
tions upon the plants, as they occur in nature, the conclu- 
sions are much more likely to be correct. 

Mr. G. H. Savur: I would like to say one word in re- 
ply to Mr. Hitechcock’s remarks regarding what we know 
about variations when we seen them in the field. It is 
my experience in the cultivation of things brought in 
from the field during the last four years, that we know 
nothing about the significance of variations in the field 
as to their bearing upon the question of the species, if 
by species we mean a continuously variable group, be- 
cause in some instances we find that very distinct varia-. 
tions as seen in the field are immediately lost when the 
individuals possessing them are grown under uniform 
conditions. We find, on the other hand, that equally dis- 
_ tinct, or even less distinct variations—as determined en- 
tirely by an estimate of the difference in form—are re- 
tained with absolute permanence so far as one can 
determine by three or four years of culture under like 
conditions. Now, how we can tell without an experi- 
mental basis for the estimation of the meaning of varia- 
tion in any particular species, what is the significance 
of those variations as we see them in the field, I am at a 
loss to understand. 


SHORTER ARTICLES AND CORRESPONDENCE 
OTTER SHEEP 


Tue following account of the ‘‘otter’’ sheep occurs in Vol. III, 
p. 134, of President Timothy Dwight’s Travels in New England 
and New York; New Haven, 1822. It is more explicit than any 
I have seen before, and may be of interest to naturalists. The 
date of the journey in which this account appears was about 1798. 

Mendon, the township mentioned, is in Massachusetts, about 
eighteen miles southeast of Worcester. 

“In this township, if I have been correctly informed, an ewe, belong- 
ing to one of the farmers, had twins, which he observed to differ in 
their structure from any other sheep in this part of the country; partic- 
ularly the fore legs were much shorter, and were bent inward, so as 
distantly to resemble what are called club feet. Their bodies were, at 
the same time, thicker, and more clumsy. During their growth they 
were observed to be more gentle, less active, less inelined to wander 
than other sheep, and unable to climb the stone walls with which this 
region abounds. They were of different sexes. The proprietor, there- 
fore, determined on an attempt to produce a breed of the same kind. 
The attempt was successful. The progeny had all the characteristics 
of the parents, and although they have since multiplied to many thou- 
sands have exhibited no material variation. I am further informed 
that the breed has been crossed with a breed of sheep common in this 
country; and in all instances.to the date of my last information, the 
lambs have entirely resembled either the sire.or the dam; and have 
never exhibited the least discernible mixture. 

“These sheep are called the Otter breed from a resemblance to the 
animal of that name. Their flesh is said to be good mutton; and their 
wool not inferior to that of common sheep, either in quantity, length, 
or fineness. But their peculiar value consists in the quietness with 
which they continue in any enclosure. In a country where stone walls 
are so general as in many parts of New England, it would seem that 
sheep of this description must be ‘almost invaluable.” 

©. L. Brisrou. 
New YORK UNIVERSITY, 
March 18, 1908. 


NOTES AND LITERATURE 
EXPERIMENTAL ZOOLOGY 


Przibram’s Experimental Zoology, of which Part I has just 
appeared,’ is an enlargement of his brochure of 1904. It is 
the author’s purpose to publish four other parts dealing re- 
spectively with Regeneration, Phylogeny, Vitality and Function. 

The present volume brings together the modern experimental 
work dealing with the egg and embryo. The results are grouped 
under the headings of Fertilization, Egg-structure, Karyokinesis, 
Gastrulation, Developmental Mechanics and Influence of En- 
vironment. There is a very full bibliography, and sixteen partly 
colored plates. These plates contain many figures familiar to 
the student of modern literature of the subject. The figures 
are often too small and their arrangement in plates at the end 
of the book is not as advantageous as figures at suitable places 
in the text would be, nor would their simple character preclude 
their insertion as text figures. 

The book will prove most useful, giving as it does a very com- 
plete résumé of the subject. The matter is treated in large 
part as a series of reviews under topic-headings of the results 
obtained by each author, and in the present state of the subject 
no other method is perhaps feasible; but while this treatment is 
satisfactory as a résumé of what has been done, it is not an 
arrangement that furnishes entertaining reading to the un- 
initiated. 

At the end of each chapter the author attempts to draw gen- 
eral conclusions from the evidence reviewed, and inasmuch as 
these conclusions serve to register the author’s point of view we 
may examine them in some detail. 

The work of recent years on artificial parthenogenesis leads 
to the conclusion, in the author’s opinion, that the cause that 
calls forth the further development of the quiescent egg-cell is 
to be found in the hastening of the vital processes already exist- 
ing in the egg by means of the withdrawal of water from the 

* Experimental bh Part I, Embryogenese. By Hans Przibram. 
Franz Deuticke, Leipzig, 
283 


284 ` THE AMERICAN NATURALIST [ Vou. XLII 


egg. Normal fertilization is supposed to act in the same way. 
The evidence at hand does not appear to the reviewer to sub- 
stantiate this generalization, because the shrinkage sometimes 
observed in the normal egg may be an effect of changes taking 
place rather than their cause, and because, in the second place, 
some of the most recent results, especially those with weak acids 
(Lefevre), can scarcely be interpreted on Przibram’s view. There 
are some indications, on the contrary, that fertilization is a vital 
act in the sense that the sperm is a stimulus starting develop- 
ment in the same way that many external agents call forth the 
nerve impulse in a nerve. Here also in the nerve the same im- 
pulse may be called forth either by internal factors or by ex- 
ternal agents. The intimate nature of irritability of living 
material remains, however, as much of a puzzle to the physiolo- 
gist as to the embryologist. 

The occurrence of visible inclusions in the egg,—pigment, 
yolk, granules, ete.,—leads the author to conclude that even be- 
fore fertilization the egg is made up of different substances, 
which ‘‘guarantee’’ the subsequent development. We touch 
here on one of the burning questions of modern embryological 
speculation, for while certain evidence seems to show that dif- 
ferent substances contained in the egg furnish a ‘‘guarantee”’ 
of ‘diversity, still the central problem remains untouched, for. 
few, if any, experimentalists will admit unreservedly that these 
materials are preformed primordia, or organ-forming substances 
in a strict sense, rather than that their presence is a condition: 
that prejudices in certain directions the subsequent development. 
In other words we are still unable to state how far and in what 
sense the development is due to preformed materials and how 
far it is an epigenetic phenomenon depending on the relation 
of the parts to each other in a dynamic sense. It may be well 
in the present unsettled state of the subject not to prejudice 
these questions, for, there may be truth on both sides, since pre- 
determination and epigenesis are not mutually exclusive possi- 
bilities, but rather complementary. 

In regard to the location of the first cleavage plane, Przibram 
points out that this is ‘‘given’’ by the location of the segmenta- 
tion spindle. The position of the spindle itself is the result of 
the egg structure, the geometrical form of the egg and the 
meridian of fertilization. The position of the spindle in any par- 
ticular case may be due to any one or to more than one of these 
factors. The causal problems still remain to be considered. 


No. 496] NOTES AND LITERATURE 285 


The division of the centrosomes, the formation of the astro- 
sphaeres, the division of the chromosomes and of the cytoplasm, 
are not to be considered, according to Przibram’s summing up, 
as constituting a series of causally connected events, but are the 
result of the same primary cause. While this point of view is sym- 
pathetic to the reviewer also, it should be clearly understood that 
we entirely lack sufficient evidence to establish such an attractive 
interpretation. Even if all these changes are the result of one 
cause, we can form no conception of what that cause may be. 
Our author’s conclusion, at the end of the next chapter, to the 
effect that this common cause is to be found in a system of 
surface tensions, can scarcely be said to be at present more than 
the working hypothesis of a few thinkers of the school of devel- 
opmental mechanics. One does not have to look very far for 
facts that are difficult to explain on such a view. 

It is pointed out at the end of chapter VI. that the arrange- 
ment of the blastomeres conforms to Plateau’s law of minimal 
surfaces. While it is true that such a law may appear to ac- 
count for cell arrangement, we should not overlook the fact that 
a similar arrangement follows if the cells are simply flattened 
against each other by pressure from outside. Possibly also 
the mutual flattening—an active proeess—of the cells them- 
selves might give the same arrangement. Therefore we do not 
know that surface tension plays even the chief rôle in the result. 
In fact, the author himself concludes in the next chapter that 
gastrulation is the outcome of chemotactic action, i. e., of an 
active wandering of the cells. Such a conclusion appears to 
admit that the characteristic feature of formative processes may 
be responsive in its nature rather than chemical or physical. 

The chapter dealing with the developmental mechanics of 
differentiation takes up the extensive literature describing the 
results of isolation of the blastomeres and of injuries to the egg. 
A very complete and impartial review is given here. Przibram 
attempts to interpret the results in the following way. Different 
chemieal stuffs are supposed to be present in different zones of 
the egg and these lead to the differentiation of the different 
organs. If parts of the egg are removed and no rearrangement 
of the formative stuffs occurs, partial development takes place; 
but if a rearrangement follows, so that the parts recover their 
normal relations of position, a whole embryo of smaller size 
results. That the different parts of the egg play the. rdle here 


286 THE AMERICAN NATURALIST [ Vou. XLII 


assigned to them can not be denied, and this is the simplest in- 
terpretation that embryologists have given to their results; but 
it is improbable that the differences between whole and partial 
development rest on this condition alone. The phenomena are 
really more complicated, as shown when whole development oc- 
curs even after the materials of the egg have become shut up 
within cells, and as shown in regeneration when a whole animal 
of smaller size develops from a part of the body of a fully formed 
organism. 

The final chapter deals with the influence of external factors, 
and, although compressed into very small compass, most of the 
modern work is referred to at least briefly. The author’s con- 
clusion that external factors play in most eases only a minor 
rôle in development will be conceded by most students of ex- 
perimental embryology. Nevertheless, important results have 
been already obtained from a study of external factors and our 
causal knowledge of the physiology of development rests in the 
main on evidence from such studies. Whether the formative 
changes are simply a complex of physiological relations or de- 
pend on factors not usually considered by physiologists is at. 
present a question of opinion rather than of demonstration. 

While we have found ourselves obliged in many cases to urge 
that many of the conclusions reached by the author still remain 
uncertain, and in other cases to take issue with the author’s sum- 
maries of the present state of affairs, yet it should. be repeated 
that the chief value of the book lies less in such generalizations 
than in the conscientious, full and exact review of the literature. 
The results so far obtained are marshaled forth in excellent 
order and the book is a valuable storehouse of materials, and 
will be found useful not only to those who do not have access 
to the original literature or time to digest it, but also to those 
who have felt themselves somewhat overwhelmed by the rapid 
development of this branch of embryology. The general reader, 
too, will find in this volume a well-balanced summing up of the 
more important results of the school of experimental embryology. 

ICHTHYOLOGY 

Jordan on Fishes.'—In a single large volume President Jordan 
presents ‘‘virtually all the non-technical material contained in 

1 Fishes. By David Starr Jordan, President of Leland Stanford Junior 
University. New York, Henry Holt and Company, 1907. Large 8vo, 
XVI + 789 pp., 18 colored plates and 673 figures. $6.00. 


No. 496] NOTES AND LITERATURE 287 


the author’s Guide to the Study of Fishes. . . . His chief aim 
has been to make it interesting to nature-lovers and anglers, and 
instructive to all who open its pages.”’ 

President Jordan can appeal to readers of any age. A de- 
lightful account of the ‘‘breeding habits of our smallest sea- 
horse, prepared by the writer for a book of children’s stories’’ is 
found on page 453. In the first chapter the author says that to 
‘‘understand a fish we must first go and catch one.’’ It is 
apparently with a boy companion that he starts for the old 
swimming hole where they catch a sunfish—‘‘a little, flapping, 
unhappy, living plate of brown and blue and orange, with fins 
wide-spread and eyes red with rage.’’ In describing its life- 
history, eating is said to be about the only thing a fish cares for. 
The black swallower engulfs a fish many times larger than itself 
(Gill) ; a single goosefish has been found with seven wild ducks 
in its stomach (Goode) ; the pike is a mere machine for the assimi- 
lation of other organisms; and the bluefish is an animated chop- 
ping machine—an unmitigated butcher (Baird). Nevertheless 
it is fortunate that the fishes can express no opinion as to two- 
mile seines and some features of the canning industry! 

A general description of the structure of fishes, of their 
habits, adaptations, colors, distribution and economic value, of 
the mermaid industry and the sea-serpent myths, form the first 
section of the book—ten chapters. 

In the remainder of the book fishes are considered systematic- 
ally, from Branchiostoma to Malthopsis. In behalf of stability, 
‘‘the sole function of the law of priority,’’ several familiar and 
established names have disappeared. Lepisosteus replaces the 
‘‘more correct but also more recent spelling, Lepidosteus.’’ The 
general reader, interested in the fishes rather than their names, 
will find that ichthyological terminology has been made as 
unobtrusive as possible. Such terms as slippery-dick and pop- 
eye grenadier make amends for considerable Greek, and common 
names are freely used. 

The reading of this book is not like a visit to a museum, or 
even to an aquarium; there is more of out-doors about it. In 
part this is due to quotations from anglers, classic and modern, 
including Van Dyke’s apostrophe to the ouananiche. Chiefly it 
is due to the author’s own experiences and such unexpected com- 
ments as—‘‘ This is the noted Aweoweo of the Hawaiians which 
used to come into the bays in myriads at the period of death of 


288 THE AMERICAN NATURALIST [ Vou. XLII 


royalty. It is still abundant, even after Hawaiian royalty has 
passed away.’’ Or—‘‘The coral reefs of the tropies are the 
centers of fish-life, the cities in fish economy. The fresh waters, 
the arctic waters, the deep sea and the open sea represent forms 
of ichthyie back-woods, where change goes on more slowly.” 
Rarely there is a defective or ambiguous sentence, such as— 
‘‘ Turner gives an account of a frozen individual swallowed by a 
dog which escaped in safety after being thawed out by the heat 
of the dog’s stomach,’’ but the book, as would be expected, is 
exceptionally well written. It is also well illustrated, and the 
figures (except Fig. 268) are carefully placed to accompany the 
text. They include a considerable number of photographs of liv- 
ing fishes, and eighteen colored plates, chiefly of fishes from the 
coral reefs of Samoa. The volume is attractively printed, except 
that Chapter XI, The Collection of Fishes, begins with a 
page on The Classification of Fishes (p. 157); whether the 
mistake is in omitting the rest of the chapter on classification or 
in printing its first page is not apparent. 

An illustrated description of the changes in the external form 
of fish eggs during their development, further accounts of nest- 
building, and the quotation of Brooks’ vivid descriptions of the 
salmon or shad, might perhaps have added to the popular inter- 
est in the book. It is, however, sufficiently large, and is full of 
authoritative information. It accomplishes all that President 
Jordan planned, and is a comprehensive introduction to a scien- 
tific knowledge of fish. 

FreDERIC T. Lewis. 
(No. 495 was issued on April 20, 1908.) : 


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WALKER PRIZES IN NATURAL HISTORY 


By the provisions of the will of the late Dr. William Johnson Walker two 
prizes are annually offered by the Boston SOCIETY OF NATURAL HISTORY for the 
best memoirs written in the English language, on subjects proposed by a Committee 
appointed by the Council. 

For the best memoir presented a prize of pric ee p be awarded ; if, ae 
eyer, the memoir be one of marked merit, the may be increased to o 
hundred dollars, at the discretion of the Gant 

For the next best memoir a prize not exceeding fifty dollars may be awarded. 

Prizes will not be awarded unless the memoirs presented are of adequate merit. 

The competition for these prizes is not restricted, but is open to all. 

Attention is especially called to the following points : 

In all cases the memoirs are to be based on a considerable body of original 
and unpublished work, accompanied by a general review of the literature of the 
ERE 

Anything in the memoir which shall furnish proof = the identity of the 
are shall be considered as —- the many from competiti 

3. Preference will be given to memoirs showing intrinsic ens of being 
a5 upon researches ant directly in compettn for the p 

Each memoir must be accompanied b sealed See enclosing the 
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year for which the prize is offered. 

5. The Society assumes no responsibility for publication of manuscript 
submitted. 

PTS FOR 1908: 

An experimental study of inheritance in animals or plants. 2. A com- 
an study of the effects of close-breeding and cross-breeding in animals or plants. 
3. A sets of animal xenekions in relation to habit formation. 4. A sect ce 

f pla it pect to leaf variation. 5. Fertiliza 

lant. 6. What proportion of a plant’s 
seasonal growth is represented i in the winter bud? ? 7. A physiographic study of the 
forms and processes discoverable along a varied shore line. 8. A problem in 
structural geology. 9. A study of one or more geological horizons with a view to 
determining the different conditions obtaining at one time over a large area, as 
recorded by sediments and fossils 
SUBJECTS FOR 1909: 

A geographic study of a district of varied features, _— as involving 
the TONE relations of inorganic and organic elements. 2. A petrographic study 
ofa district of crystalline rocks. 3. A paragenetic study of a mineral locality. 4. 


ey MS VLG (os 
+ 


history of a thallophyte, with special reference to merce. 6. Contribution to 
our knowledge of response in plants. 7. The factors governing orientation in animal 
responses, 8. The relation between primary aie secondary sex characters in 
animals. 9, The activities of the animal body in relation to internal secretions. 


GLOVER M. ALLEN, Secretary 


VOL. XLII, NO. 497 * MAY, 1908 
THE 


AMERICAN 
NAFURALISI 


A MONTHLY JOURNAL 
DEVOTED TO THE NATURAL SCIENCES 
IN THEIR WIDEST SENSE 


CONTENTS 
Page 


- 


Geographical Distribution ; Origin of the Bermuda aA 
rofessor A. E = vEnnits 289 
II. On the omaha of Certain Tropisms of Insects. CHARLES THOMAS 
BRUES ğ 5 è 297 
III. TheEvoluti f Tertiary M l itl f their Migrations. 
Professor CHARLES DEPERET 303 
IV. On porns e E of Leaf Structure in cian Agaves and Noli- 
essor J. F. McCLENDON 308 
The Biotorea hatoki of the ween. of Fisheries ves ch Hole, 
Mas eport of Work for the Season of 1907. Dr. FRAN B. SUMNER 317 
imee of Hair Form in Man. GERTRUDE C. BAE, and CHARLES 
DAVENPORT 341 
VII. Notes and Literature : E E e T RERET in Recens Ciioids, 
. L.C. Animal Behavior—Recent Work on = ee of vee ~ gher 
Animals. Professor HERBERT S. JENNINGS. . 350 


s 


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THE 
AMERICAN NATURALIST 


VoL. XLII May, 1908 No. 497 


GEOGRAPHICAL DISTRIBUTION; ORIGIN OF 
THE BERMUDIAN DECAPOD FAUNA 


PROFESSOR A. E. VERRILL 


YALE UNIVERSITY 


Iy a report now in course of publication’ on this group, 
78 species, subspecies or named varieties are discussed, 
of which 16 have not been previously recorded From 
Bermuda. Among these, six are described as new. 

Of the total number, 72, equal to 93 per cent., have been 
recorded also from the Florida Keys or the West Indies, 
or from both, demonstrating the close faunal relations of 
the two regions. The macruran Decapoda (35 species} 
show similar relations. 

About 53 of the forms (about 68 per cent.) range from 
Florida to Pernambuco, Brazil, or farther south. 

A considerable number, about 25 species, or 31 per 
cent., extend their range north of Florida to the coast of 
South Carolina or farther north, the greater portion of 
these reaching Cape Hatteras. Six or seven reach south- 
ern New Jersey. 

Two species, Callinectes sapidus, Eupanopeus Herbstii 
and its var. obesus, range northward to southern New 
England, as permanent residents. 

Several others occur occasionally or sporadically on 
this coast, being carried northward by the Gulf Stream, 
or by shipping, but fail to become naturalized so far 
north, owing to the cold of winter. 

i rans. Conn. Academy of Sciences, Vol. XIII,- pp. 299-473, plates 
1X—Xxviii, 


289 


290 THE AMERICAN NATURALIST [ Vou. XLII 


Fie. 1. Sesarma Ricordi, var. terrestris, nov. Co-type; x about 2. Phot. 
A. H. Verrill. 


7 ` a of 
Fic. 2. Achelous Smithii, nov.; cotype, dorsal view ; x about iyo $ 2b, chel 
2 


the same, front view. Phot, A. H. Verrill. 


No. 497] BERMUDIAN DECAPOD FAUNA 291 


It is evident, therefore, that the Bermuda decapod 
crustacean fauna is an offshoot or colony from the West 
Indian fauna, with only a slight admixture of species 
from other regions. In this respect the Crustacea agree 
with the Anthozoa, Mollusca, Echinoderms, ete. 

The additions to the fauna of Bermuda, including the 
new species and varieties, are as follows: 

* Sesarma Ricordi, terrestris, subsp. nov. See Science, Vol. XXVII, 
p. 491. Fig. 1. 

* Eupanopeus Herbstii, minax, subsp. nov. 

* Eupanopeus bermudensis, var. sculptus, nov. 

Callinectes Dane Smith 

Callinectes marginatus, Treeni (Ord.). 

Achelous Smithii, nov. Fig. 2 

Achelous Gibbesii Stimpson. 

Charybdella tumidula Dena 


Mithrax cornutus Sauss 

Challenger Bank, 30 a Field Museum Nat. Hist., 1905. 

Parthenope (Platylambrus) crenulatus (Saus.). Fig. 5. 
Challenger Bank. Bermuda Biological Station, 1903. 
Troglocarcinus corallicola, gen. et sp. nov. Fig. 3. 
Parasitic in living corals (Mussa, Mæandra). 
Dromia crythropus (Edw). Fig. 
Argus Bank, 30—40 fathoms. Field Mus. 
Dromidia antillensis Stimpson. Fig. 4. 
Challenger Bank. Bermuda Biological Station, 1903. 
* Petrolisthes sA gud var. nov. 
unida Beanii, sp. n 
Argus Bank, 50 tons Field Mus. Nat. History. 
Dardanus venosus (M.- 
Previously recorded anes the name of D. insignis, which is a dis- 
tinet species. 
* Clibanarius hebes. sp. nov. 

Those with an asterisk prefixed are known only from 
Bermuda. 

The following 25 species range Loiri on the 
American coast to or beyond South Carolina, as perma- 
nent residents: 

Ocypode arenarius. (To N. Jer- Portunus Sayi. 
sey. Achelous anceps. 

Planes minutus. (To N. Jersey.) A. Gibbesii. 

Plagusia depressa. A. spinimanųs? 


292 THE AMERICAN NATURALIST [ Vou. XLII 


FIG. 3 


Fra. 3, 


FIG. 4 


Troglocarcinus corallicola, nov., 9, partially out of its den in a 
coral (Mussa) from Dominica I; x about 2. 


The crab was intentionally placed 


in a den belonging to an older individual, otherwise but little of it could be 


seen. Phot. A. H. Verrill. 


Fic. 4. Dromidia antillensis; about nat. size. Phot. A. H. Verrill. 


Cycyloxanthops denticulatus. 

Eupanopeus Herbstii. (To 
Cod.) 

E. Herbstii. obesus. (To C. Cod.) 

E. occidentalis. 

Eurytium limosum. (To N. Jer- 
sey. 

Eriphia gonagra. 

Callinectes ornatus. 

C. sapidus. (To €. Cod.) 


A. Smithii, nov. 

A. Sebe. 

A. Ordwayi. 

A. depressifrons. 
Stenorhynchus sagittarius. 
Podochela Riiset. 

Mithrax forceps. 
Macroceloma trispinosum. 
Calappa marmorata. 
Petrolisthes armatus. 


Fic. 5.  Parthenops crenulatus; x about 3. Phot. A. H. Verrill. 


Several of the species, mostly grapsoids, are found m 
most, or all, tropical seas, as well as in the West Indies. 


They are as follows: 
Grapsus grapsus. 
Geograpsus lividus. 


Plagusia depressa. 
Perenon planissimum. 


No. 497] BERMUDIAN DECAPOD FAUNA 293 


Pachygrapsus transversus. Domecia hispida. 
Planes minutus. Petrolisthes armatus. 

Nearly all the widely distributed species, included in 
the last list, are found on the West Coast of Africa. But 
some additional species, common to Bermuda and the 
West Indies, are also found on n the West African coast. 


Namely: 

Goniopsis cruentatus. Calappa marmorata. 
Callinectes marginatus ? larvatus. C. gallus, galloides. 
Stenorhynchus sagittarius. Hippa cubensis. 


Aside from the widely distributed grapsoid crabs, 
found in all tropical seas, very few of the Bermuda 
species are found on the Pacific coasts of Central and 
North America. But some others are represented there 
by closely allied species or subspecies. The species that 
have been considered identical by recent good authorities 
are as follows: 


Goniopsis cruentatus. * Domecia hispida. 
* Grapsus grapsus. Epialtus bituberculatus (varie- 
* Geograpsus lividus. ties). 
* Pachygrapsus transversus. * Calappa gallus (varieties). 
* Planes minutus. Cycloés Bairdii (varieties). 
* Plagusia depressa. . Petrolisthes armatus. 


* Percnon planissimum. 

Those preceded by an asterisk are cireumtropical. 

It is well known that a considerable number of species 
of Mollusca, Echinoderms, Anthozoa, etc., as well as 
Crustacea, are common to West Africa, Brazil and the 
West Indies. Such species may have originated on 
the African coast and thence migrated across the At- 
lantic to South America, and thence northward to the 
West Indies, Florida and Bermuda, during recent geo- 
logical times. All the species of Decapod Crustacea 
having this wide range exist for a considerable length of 
time as free-swimming larval forms, in the zoéa and 
megalops stages. These larval forms may be carried 
long distances by the prevailing oceanic currents, espe- 
cially in the regions of the trade winds. 

It is scarcely admissible to suppose that they could have 


294 THE AMERICAN NATURALIST [ Vou. XLI 


traveled in the opposite directions, against the currents, 
unless by human agency, in recent times. 

Many Crustacea, including the higher and more active 
forms, especially the grapsoid and cancroid crabs, are in 


Fic. 6. Cycloes Bairdii, var. atlantica, nov., ~, nat. size. Phot. A. H. Verrill. 


the habit of hiding among the clusters of barnacles, ete., 
attached to the bottoms of vessels, and in this way they 
may be carried across the oceans in any direction, so long 
as the temperature of the water is suitable for their exist- 
ence. In this way many tropical species reach the New 
England coast in summer, but die out during the winter. 

Several species of crabs and shrimps habitually live 
among floating sargassum, or attached to floating drift- 


Saati a Sa ae 


Fic. T.. Dromia erythropus from Dominica, with a flat Chalinid sponge held 
over its back, about 1% nat. size. Phot. A. H. Verrill. 


No. 497] BERMUDIAN DECAPOD FAUNA 295 


wood. This is the case especially with Planes minutus, 
Portunus Sayi, and some others. That they have mi- 
grated to Bermuda in this way is very evident, for they 
do so constantly, day by day, at the present time. 

But the majority of the species common to Bermuda 
and the West Indies do not have such habits, and must 
have migrated northward in the free-swimming larval 
stages. The directions of the Gulf Stream and prevail- 
ing wind currents are favorable for the transportation of 
free-swimming animals from the Bahamas, Cuba, etc., to 
the Bermudas. 

On the other hand, very few, if any, strictly Hast Amer- 
ican species have established themselves in the Bermudas, 
notwithstanding the constant passage of vessels in that 
direction for nearly three hundred years. Perhaps the 
temperature of the Gulf Stream is too high to allow such 
species to be carried across it, or they may not be able to 
endure the summer temperature of the Bermuda waters. 

There are, likewise, no Decapod species of European 
or Mediterranean origin known in the Bermuda fauna, 
though such are known to occur in other orders, espe- 
cially in those groups that habitually cling to the foul 
bottoms of vessels. 

It would be of great scientific interest, as well as evi- 
dent economical benefit, to experiment with the introduc- 
tion of edible East American and West Indian crustacea 
that do not now exist at the Bermudas. Among those 
that might succeed are the large southern rock crab 
(Menippe mercenaria); the West Indian rock crab 
(Carpilius corallinus) ; the southern variety of the edible 
blue crab (Callinectes sapidus) ; and many others. Prob- 
ably their fertilized eggs could be transported far more 
easily than the adults, and in vastly greater numbers. 
With suitable arrangements at the new Bermuda Bio- 
logical Station, such eggs could easily be hatched and 
the young liberated in great numbers, in suitable places. 

It would probably be useless to attempt to introduce 
those species that are restricted to our coast north of 


296 THE AMERICAN NATURALIST [Von XLII 


Cape Hatteras, such as the common lobster, but there 
seems to be no reason why any species from the Carolina 
coasts or the Florida Keys should not flourish in Bermuda 
if once introduced there in considerable numbers and 
protected from their enemies at first. 

Probably hundreds of species have been accidentally 
carried there, singly or in small numbers, in past times, 
which have failed to establish themselves, either because 
they became too far separated to find their mates at the 
breeding season, or because they were too soon eaten up 
by voracious fishes. Yet a single female crab, carrying 
fertilized eggs, might succeed in introducing the species, 
for their eggs often amount to 5,000, or even 10,000: at 
one time. Aside from edible species, the introduction of 
the smaller kinds would afford a large additional supply 
of food for useful fish, and thus benefit the fisheries. 


ON THE INTERPRETATION OF CERTAIN 
TROPISMS OF INSECTS? 


CHARLES THOMAS BRUES 


MILWAUKEE PUBLIC MUSEUM 

THE great interest which has developed among zoolo- 
gists during recent years regarding the behavior of 
animals has resulted in such a large number of papers 
on tropisms and related topics, that a short discussion 
of the matter in regard to insects may seem rather un- 
called for at present. 

The field of entomological research affords, however, 
so many possibilities in this line that the activity which 
was formerly confined to studies of lower invertebrates 
is gradually showing a tendency to shift or to widen out 
toward the insects in its search for fresh subjects, and 
already the reactions of various species belonging to 
several groups have been investigated by the commonly 
accepted methods. The problem of studying the re- 
sponses of insects to light, gravity, mechanical stimuli, 
etc., involves so many factors which do not enter into any 
consideration of simple organisms like protozoa or 
planarians that its complexity is rarely appreciated by 
those who give it their attention. The former animals 
can be brought into the laboratory and placed where the 
normal conditions of their natural environment are repro- 
duced more or less faithfully. Under such circumstances 
their reactions and behavior can be analyzed by means 
of different mechanical contrivances which have been 
devised to test the influence of certain stimuli to the ex- 
clusion of others. To be brief, experience has shown that 
conclusions derived from such experiments are fairly 
trustworthy, and that a close approach can be thus made 

1A paper read before the joint meeting of the Wisconsin Academy of 
Sciences, Arts and Letters and the Wisconsin Natural History Society at 
Milwaukee, February 13, 1908. 


297 


298 THE AMERICAN NATURALIST [ Vou. XLII - 


to an understanding of the animals’ behavior in their 
natural environment. The extension of these methods 
into the study of such highly specialized and delicately 
organized invertebrates as insects is fraught by many 
dangers, and the failure to recognize certain inherent diffi- 
culties must inevitably invalidate some of the general 
conclusions which have been recently announced. 

Without reference to the psychological aspect of insect 
behavior which I am in no way competent to consider, 
there are a number of factors entering into the study of 
reactions which I believe must be recognized if we are to 
appreciate the fundamental difference between a natural 
environment and an artificial reproduction of its single 
features in the laboratory. 

Probably more experiments on insects have been re- 
corded which bear upon the phenomena of phototropism 
than upon any other single tropism, and we may there- 
fore reasonably suppose that the results in this field rep- 
resent actual conditions as well as, if not better than, 
those on other tropisms. 

Turning to a recent paper by Frederick W. Carpenter 
on the reactions of the pomace-fly, Drosophila ampelo- 
phila, to various stimuli,? we see the statement: 

‘‘Light has both a kinetic and directive effect. The insect moves 
toward the source of light, being positively phototropic. The directive 
effect is apparent only when the kinetie stimulus is sufficient to induce 
locomotion.” 

This is merely a concise expression of the fact which 
we have all observed many times of the fly buzzing on 
the window. Under such conditions most Diptera are 
positively phototropic and will go through long series of 
alternating periods of activity and quiescence, the former 
usually induced by some external stimulus; attempting 
all the while to pass through the window toward the source 
of illumination. With many species this may often con- 
tinue until the death of the insect from exhaustion and 
lack of food. 

? AMERICAN NATURALIST, vol. 39, pp. 157-171, 1905. 


No. 497] TROPISMS OF INSECTS 299 


Such are the results of experimentation where the trans- 
parent sheet of glass has been allowed to change the nor- 
mal conditions of environment. Let us suppose, however, 
that the fly be allowed to pass out of the window into 
a more nearly natural environment. It immediately flies 
into the open, but does not endeavor for any length of 
time to continue its positively phototropic movements. 
Once unrestrained it is soon again following the normal 
pursuits of its particular species, which in the case of the 
aforementioned Drosophila is principally to locate decay- 
ing vegetable matter which will be suitable for food. 
breeding, and oviposition. It is evident in this case that 
the universal and quick response of the Drosophila to 
light when confined is due to some added factor in the 
experiment which. I hope to point out on a later page. 

Another paragraph in the same paper refers to results 
obtained under still more unnatural conditions. 

‘‘The exposure of Drosophila to light of high intensity is accom- 
panied by an increase in the kinetic effect. Under the influence of 
the highest intensity used, that of a 250 c.p. are light at 40 cm., the 
muscle reflexes of an insect become very rapid and violent, and the 
directive influence of the light seems inhibited.’’ 

When we realize that these insects are as quick as 
ourselves to appreciate sudden changes in light and shade 
at short distances, it is not astonishing that they are un- 
able to orient themselves under such startlingly unnatural 
conditions, placed only sixteen inches from an are light, 
and their behavior here can not be compared with their 
reactions to normal daylight or sunlight. In fact the per- 
version of instinct induced by electric are lights is a 
common experience with many nocturnal insects which 
are attracted in countless numbers, while their normally 
phototropic diurnal relatives are disturbed scarcely at 
all by the presence of the lights. 

This too, is a matter of common experience, which has 
found expression in the adage of the moth and the flame. 
Most of the Lepidoptera heterocera are negatively photo- 
tropic, venturing out at dark and concealing themselves 


300 THE AMERICAN NATURALIST [ Vou. XLII 


from the light during the day, yet the proximity of an 
unnaturally brilliant light quickly upsets their normal 
instincts, and they are irresistibly attracted, although 
the appearance of the moon or the dawn affects them in 
no such manner. 

Another tropism which is easily investigated by ex- 
perimental observation is geotropism, and the agreement 
reached by a number of workers is that many insects 
when confined in an unnatural environment are negatively 
geotropic. To quote again from the same paper on 
Drosophila: 

‘Gravity has a directive effect upon the active insect which is 
‘negatively geotropic, that is, the insect moves away from the center 
of the earth.’’ 

Such is indeed the action of almost any insect, par- 
ticularly an active species or a flying one when placed in 
any sort of a receptacle where it is deprived of food, or 
_where it can not enjoy the freedom to which it is accus- 
tomed. It immediately flies or crawls upward, and usu- 
ally will repeat the process almost indefinitely. if for any 
_ reason it finds itself again at the bottom. Since it always 
goes to the top of the jar if not attracted in another direc- 
tion by other stimuli, negative geotropism is taken to be 
one of its normal attributes. 

This negative geotropism, however, becomes an ab- 
surdity as soon as we attempt to apply it in a general 
way to insects in their natural environment. Crawling 
insects do not congregate at the tops of objects in their 
environment, and neither do flying insects approach high 
altitudes, far from the surface of the earth. After their 
first escape from unnatural restraint, their negative geo- 
tropism vanishes as quickly as did their positive photo- 
tropism. The effect of any sudden and unnatural dis- 
turbance on the action of a flying insect is very easy of 
observation and is experimentally tested many hundreds 
of times during a season by any active collector of in- 
sects. Take, for example, a common bumblebee, which on 
account of its large size can be easily followed by the eye 


No. 497] TROPISMS OF INSECTS 301 


as it passes from flower to flower, often traversing a con- 
siderable space in a nearly straight line toward a particu- 
lar plant whose location may be known to it through past 
experience. Thus it continues along, sometimes rising 
slightly or flying lower, but exhibiting no movements 
whatever which could be attributed to geotropism or 
phototropism. 

Let it be caught in the collector’s net, however, and it 
immediately develops the negative geotropism, flying 
wildly about and seeking to ascend. If the net be kept 
inverted it will not escape until it accidentally drops out 
as a result of flying at the cloth of the net or of losing its 
foothold in crawling upward. Once out, it soars upward 
perhaps a short distance, and then resumes its former 
occupation. 

Do these actions of the fly and the bee when confined, 
which are characteristic of other insects as well, represent 
their normal tropisms? 

It has been usually assumed that they do, and several 
ingenious explanations have been suggested which en- 
deavor to show why phototropism and negative geo- 
tropism become inactive in nature after certain periods, 
since the logical result of their continued action never 
presents itself to observation. 

From the behavior of species in nature, these are most 
‘certainly not normal and are evidently caused by the con- 
ditions of the experiment. The most probable explana- 
tion of their appearance is that they are the expression of 
an instinct to seek the open whenever disturbed. In 
nature this freedom can always be obtained by flying up- 
ward and toward the light, that is to say, by phototropic 
and negatively geotropic movement which carries them 
away from all obstacles. Such a reflex in response to 
disturbances is a very valuable one and is no doubt main- 
tained by natural selection, since it automatically offers an 
avenue of escape from disturbing conditions or danger. 

In some species this reflex is in another direction, and 
these exceptions are most instructive in support of this 


302 THE AMERICAN NATURALIST [Vou. XLII 


idea. Bees of the parasitic genus Celioxys when caught 
in the net almost invariably fly downward at the first im- 
pulse, being thus positively instead of negatively geo- 
tropic. A reason for this adaptation can be suggested 
from a knowledge of their habits. Graenicher® has re- 
cently shown that Coelioxys enters the nests of other bees 
to lay its eggs. Thus in the event of its discovery by the 
rightful owner of the nest, it may drop to the ground with 
much better chances for escape than it would otherwise 
have. 

Tiger beetles of the genus Cicindela are active fliers, but 
are more at home on the ground, consequently when cov- 
ered by the net they never rise on the wing, but invariably 
attempt to escape on the surface of the ground, which 
they can readily do if the net does not fit very closely. 
Their actions can thus be traced directly to an adaptation. 

From any unbiased review of such facts, I think it will 
appear that we can not hope to make wholly satisfactory 
progress along the line of interpreting insect behavior by 
means of studying their responses to stimuli in the labora- 
tory, unless this be done with careful reference to their 
habits and behavior in nature, and in relation to the 
various external factors of their environment. 

* Bull. Wisconsin Nat. Hist. Soc., vol. 3, p. 162, 1905. 


THE EVOLUTION OF TERTIARY MAMMALS, AND 
THE IMPORTANCE OF THEIR MIGRATIONS 


PROFESSOR CHARLES DEPERET 
UNIVERSITY OF LYONS 
Tarp Paper! Miocene Epocn. 


AFTER having investigated the migrations of the Eocene 
and Oligocene epochs (Comptes rendus, 6 novembre, 1905, 
et 12 mars, 1906), I will now consider those of the Miocene. 

©. Miocene Fauna.—I. Lower Miocene (Burdigalian), 
fauna of the sands of the Orléanais: principal localities 
(Neuville-aux-Bois, Marigny, Rebréchien, Fay-aux-Loges, 
Beaugency, Tavers, Les Barres; Chevilly, Neuvilly, Ar- 
tenay, Ruan, Chilleurs, Suévres, Pontlevoy, Thenay, 
Blasois, Chitenay; Manthelan, ete.), and of the limestone 
of Montabuzard, underlying the sands.—The marine de- 
posits of Eggenburg and Linz (Lower Austria), of the 
‘* Wuschelsandstein’’ of Bruttelen, Macconens, La Mo- 
liére, Bucheggberg (Switzerland), of Saint-Nazaire-en- 
Royans (Drôme), of the white Molasse of Angles (Gard), 
of Horta de Tripas near Lisbon.—Fauna of the fissures 
of the Solenhofen quarries. 

1. Local Evolution.—Continuance of Tapiride (Par- 
atapirus), of some genera of Rhinocerotide (Acera- 
therium, Diceratherium), of Chalicotheriide (Macro- 
therium), of Anthracotheriide (Brachyodus becoming 
extinct), of Suide (Paleocherus, Hyotherium), of Tragu- 
lide (Hyzmoschus), of Cervuline (Paleomeryx, Dicro- 
cerus), of Castoride (Steneofiber), of Cricetine (Crice- 
todon), of Lagomorph Rodentia (Prolagus), of Talpide 
(Talpa), of Tupaiide (Galerix), of Canide (last of 

1 Extract from the Comptes rendus des séances de l’Académie des Sei- 
ences, t. CXLIII, p. 1120 (séance du 24 décembre, 1906). Translated by 
Johanna Kroeber. First and second papers, Eocene and Oligocene, in the 
February and March numbers of the NATURALIST. 

303 


304 THE AMERICAN NATURALIST [Vou. XLII 


Cephalogale), of Amphicyonine (Amphicyon), of Mus- 
telide (Stenogale, Paleogale, Stenoplesictis), of Lutrinæ 
(Lutrictis, Lutra), of Felide (Pseudelurus, Machairodus). 

2. Very Important African or Afro-Asiatic Migra- 
tions of Proboscidea (Mastodon, Dinotherium), of Anti- 
lopine (Protragocerus), of certain Cervuline (Micro- 
meryx), of some Rhinocerotide (Teleoceras, Ceratorhi- 
nus), of some Suide (Cherotherium, Listriodon), and of 
anthropoid apes (Pliopithecus). 

3. North American Migration of Equide (Anchithe- 
rium). 


II. Middle Miocene (Vindobonian, divisible into three 
substages: Helvetian, Tortonian, Sarmatian). Corre- 
sponding to these three substages are three mammalian 
faunx, grading into one another by almost imperceptible 
transitions. These assemblages may be denoted as fol- 
lows, the names being derived from those localities in the 
sub-Pyrenean basin where each is typically represented: 
(1) horizon of Sansan, (2) horizon of Simorre, (3) hori- 
zon of Saint-Gaudens. 

1. Horizon of Sansan.—Principal localities: Sansan, 
Jegun (Gers), caleareous marls of the Loire (Pontlevoy, 
Sainte-Maure, Manthelan); marine Molasse of the en- 
virons of Romans (pont de 1’Herbasse, Bren, Clérieux) ; 
marine Molasse of Suabia (Baltringen, Rammingen, 
Heggbach, Hausen; Niederstozingen, Siissen, Ursendorf, 
Hochgeland) ; of the lignites of Styria (Hibiswald, Gö- 
riach, Wies, Voitsberg, Gamlitz, Parschlug, Neufel) and 
of Lower Austria (Leoben, Leiding, Feisternitz, marine 
sands of Grund at Guntersdorf); Georgengsmund (Ba- 
varia), Engelswies (Baden). 

2. Horizon of Simorre.—Principal localities: Simorre, 
Bonnefond, St. Cristan, Tournon, Villefranche d’Astarac, 
l’Tle-en-Dodon (Gers); Saverdun (Ariège); marine de- 
posits of Mirabeau (Basses-Alpes), of Sorgues (Vau- 
cluse), of Romans (Drôme) ; Steinheim, Nordlingen, Ries, 
Althausen, Urlau (Suabia); Hohenhoven (Baden) ; intra- 


No.497] EVOLUTION OF TERTIARY MAMMALS 305 


Alpine basin of Vienna (Dornbach, Vordersdorf, Fiinf- 
kirchen, Loretto, Bruck-a.-Leitha, Breitenbrunn, Marga- 
rethen, Mannersdorf, Neudorf); Abstdorf, Franzensbad 
(Bohemia); Wosskressensk (Russia); Pesth, Ssoskut 
(Hungary); Trauenzinen (Silesia), Krivadia and Gyulu- 
Mendru (Transylvania). 

The rich ‘‘terrain sidérolithique’’ (‘‘Bohnerz’’) of La 
Grive-Saint-Alban (Isère), of Mont Ceindre (Rhône), of 
Pretty near Tournus (Saône-et-Loire), of Gray (Haute- 
Saône), of Mésskirch, Genkingen, Willmardingen, Heu- 
berg, Melchingen, Jungnau (Suabia) belong in large part 
to this horizon. 

3. Horizon of Saint-Gaudens. — Principal localities: 
Valentine, Saint-Gaudens, Montréjau (Haute-Garonne) ; 
Delsberg, le Locle, La Chaux-de-Fonds, Vermes, Oenin- 
gen, Ellg, Kapffnach, Weltheim (Switzerland); Heder, 
Dinkelscherben, Günsburg, Diessen, Reichenau, Reisens- 
burg, Dasing, Fraising, Tutzing, Stätsling, Reicherts- 
hofen, Frontenhausen, Flinz of Munich, Sankt Georgen 
(Bavaria); Hernals, Heiligenstadt (Vienna basin); Mt. 
Bamboli (Tuscany); San Isidro near Madrid; Aveiras 
de Baixo (Portugal) ; Kriwoi-Rog, Nicolaieff, Sébastopol, 
Tiraspol (Russia). 

1. Local Evolution.—Continuance of Equide (Anchi- 
therium), of Tapiride (Paratapirus), of Rhinocerotide 
(Aceratherium, Teleoceras, Ceratorhinus), of Chalico- 
theriide (Macrotherium), of Suidæ (last representatives 
of Hyotherium and Cherotherium; Listriodon; finally 
Sus itself), of Tragulide (Hyzmoschus), of Cervuline 
(Dicrocerus, Micromeryx, last representatives of Palxo- 
meryx), of Antilopine (Protragocerus), of Proboscidea 
(Mastodon, Dinotherium), of Theridomyide (last rem- 
nants of Theridomys), of Myoxide (Myoxus), of Sciu- 
ride (Sciurus), of Castoride (Steneofiber), of Cricetine 
(Cricetodon), of Lagomorph Rodentia (Prolagus, La- 
gomys), of Talpide (Talpa, Proscapanus, Scaptonyx), 
of Myogalide (Myogale), of Tupaiide (last of Galerix 
and Lantanotherium), of Soricidæ (Sorex, Crocidura). 


306 THE AMERICAN NATURALIST [Von XLII 


last Dimylide (Plesiodimylus), of Erinaceide (Erina- 
ceus, last of Paleoerinaceus), of Chiroptera (Rhinolophus, 
Cynonycteris, Vespertilio, Vesperugo), of Canide (Gale- 
eynus), of Amphicyonine (Pseudocyon, Hemicyon, Dino- 
eyon, last Amphicyon), of Mustelide (Haplogale, Ste- 
nogale, Pseudictis, Mustela, Paleogale, Proputorius, 
Trochictis, Trochotherium), of Lutrine (Lutra, Enhy- 
driodon), of Viverride (Viverra, Herpestes, Progenetta), 
of Felide (Machairodus, Hyenailurus, last Pseudelurus, 
first true Felis). 

2. Migration of South American origin (by way of 
Africa) of the Hystricide (Hystrix). 

3. Migrations, Probably Asiatic-African, of the Ursidæ 
(several branches, Pseudarctos, Hyænarctos, Ursavus), 
of the catarrhine monkeys (Oreopithecus), and anthro- 
poids (Dryopithecus). 


III. Upper Miocene (Pontian). Fauna of Pikermi.— 
Principal localities: Pikermi (Greece); Isle of Samos 
(Asia Minor); Maragha (Persia); Tchernigow, sands of 
Balta, limestone of Odessa and of Groussolowo (Russia) ; 
Manzati (Roumania) ; Baltavar, ignites « of Baroth- Kopecz 
(Hungary) ; Eppelsheim (Germany) ; Siebenhirten, Con- 
geria gravels of the Vienna basin, vicinity of Eggenburg 
(Lower Austria); Mont Luberon, Visan (Vaucluse), Au- 
bignas (Ardèche), Puy-Courny (Cantal), Saint-Jean-de- 
Bournay, La Tour-du-Pin, La Trappe de Chambaran 
(Isère), Montmirail, Tersanne (Drôme), La Croix-Rousse 
and Sainte-Foy à Lyon, Ambérieu, Soblay, Saint-Jean- 
le-Vieux (Ain), rocher du Dragon at Aix-en-Provence, 
Montredon (Hérault), Estavar (Cerdagne), Orignac 
(Hautes-Pyrénées); Concud (Spain); Archino (Portu- 
gal); Grasitelli (Sicily). 

To the same horizon belongs the greater part of the 
‘‘terrain sidérolithique’’ of Salmendingen, Melchingen, 
Trochtelfingen, Ebingen, Undingen, Heuberg (Suabia). 

1. Local Evolution.—Continuance of Tapiride (Tapi- 
rus), of some groups of Rhinocerotide (Ceratorhinus, 


No. 497] EVOLUTION OF TERTIARY MAMMALS 307 


last Aceratherium and Teleoceras), last Chalicotheriide 
(Chalicotherium), of Suide (Sus, last Listriodon), of 
Tragulide (last Hyzmoschus), last Cervuline (Dicro- 
cerus, Micromeryx), of Castoride (last Chalicomys, 
earliest Castor), of Hystricide (Hystrix), of Canide 
(Simocyon), last Amphicyonine (Dinocyon), of Urside 
(Hyænarctos, Ursavus), of Mustelide (Mustela,. Pro- 
meles, Promephitis), of Viverride (Ictitherium), of Fe- 
lide (Machairodus, Felis), of anthropoid apes (Dryo- 
pithecus, Anthropodus). 

2. North American Migrations (perhaps by way of 
Asia) of one of the Equide (Hipparion) and of the Lepo- 
ridæ (Lepus). 

3. Afro-Asiatic Migrations of some Rhinocerotidæ 
(Atelodus), of Cervide (Capreolus), of Giraffide (Hella- 
dotherium, Paleotragus, Camelopardalis, Samotherium), 
of several groups of Antilopide (Paleoryx, Gazella, 
Paleoreas, Protragelaphus), of Ovide (Criotherium), of 
Hyenide (Lychyena, Hyenictis, Hyena), of Muride 
(Acomys), of catarrhine monkeys (Mesopithecus). 


ON XEROPHYTIC ADAPTATIONS OF LEAF 
STRUCTURE IN YUCCAS, AGAVES 
AND NOLINAS'! 


PROFESSOR J. F. McCLENDON 


UNIVERSITY or MISSOURI 


Zootocy and botany are now so separated, and for a 
worker in one field to venture into the other is so unusual 
that it may not be out of place to state my reasons for 
presenting this paper, which are as follows: 

1. Practically all of the material was worked up in 
1903-4, and since I shall not have opportunity to complete 
the study I wish to make this part available. 

2. I wish to emphasize the importance of the results of 
plant physiology to the zoologist. Many of those phe- 
nomena now brought into such prominence in zoology 
(z. e., trophisms, heteromorphosis and the mutually anti- 
toxic action of sodium and calcium) were discovered in 
plants and later studied in animals. Likewise the study 
of the water economy of desert plants may ultimately 
throw some light on similar processes in animals that are 
subjected to constant (i. e., Dermestes) or periodic lack 
of water (i. e., rotifers). The cutin of plants and the 
chitin of animals play similar rôles, and it may be that 
the carbohydrate and mucoid (?) water-storing sub- 
stances in plants have analogues in animals. 

I am indebted to Dr. W. L. Bray for suggesting and 
directing this study, and for procuring the material, most 
of which he obtained from Langtry, Texas and from the 
Missouri Botanical Garden. 

Methods.—The most serviceable method for investiga- 
ting cell walls was free-hand sections stained in chlorio- 

1 Contribution from the Botanical Laboratory of the University of Texas 
under the direction of Dr. W. L. Bray. 

308 


No. 497] ON XEROPHYTIC ADAPTATIONS 309 


dide of zine. A freezing microtome might have been 
of service. Celloidin did not penetrate thoroughly in six 
weeks and was abandoned. Thin paraffine sections were 
cut, but where bundles were isolated in succulent tissue 
they usually tore through part of the latter. The ex- 
perimental side of the subject was not touched. 

Yucca and its allies are mostly xerophytic plants that 
have been modified along various lines to adapt them to 
their xerophytic habitat. Root, stem and leaf are suc- 
culent, thus serving for water-storage tissue. The leaves 
are closely set in a rosette, thus protecting one another 
against too great insolation and transpiration. In 
Agave, Hesperaloe, Dasylerion, Nolina and some species 
of Yucca the stalk is very short, thus enabling the leaves 
to shade the ground over the larger roots and protect 
them from drying. The leaves are especially modified: 
the epidermis is greatly thickened and heavily cutinized, 
the skeleton more or less rigid, the stomata sunken 
beneath the surface, either singly or in grooves, and the 
assimilation tissue many layers thick. 

The Respiration System.—The simplest type of stoma 
in this group is probably found in Yucca aloifolia tenui- 
folia (Figs. 1 and 2). In this species the guard cells 
are not sunken much beneath the general epidermal sur- 
face, but the very thick epidermis is pierced by an air 
passage nearly square in cross section (Fig. 1), leading 
to the slit between the guard cells. Beneath the guard 
cells is an intercellular air space of considerable size 
leading into small intercellular air spaces. The epi- 
dermis is heavily cutinized and the cutin extends inward 
through the stoma and lines the upper part of the air 
space beneath. The assimilation tissue is palisade near 
the epidermis; but the cells show a tendency to arrange 
themselves radially around the vascular bundles. There 
are large intercellular air spaces in the interior of the 
leaf. Stomata of like character were found in Yucca 
aloifolia, Y. aloifolia marginata, Y. aloifolia conspicua, 
Y. gloriosa and Y. gloriosa flexilis. 


310 THE AMERICAN NATURALIST [ Vou. XLII 


(In diagrammatic cross sections mechanical tissue is black and vascular 
tissue cross striated.) 
Stoma of Yucca aloifolia 00 98 thane view. 
The same in cross section of 1 
Stoma of Agave deat in cross section of leaf. 
e—surface v 
Stoma of Darrai teranum in cross section of leaf. 
Stoma of Agave americana—surtf: 
Stoma of lower side of leaf of Yucca reourctfola—dotted lines repre- 
sent portions of ee int that are covered by the other two 
Same in cross section of lea 
Stoma of si adiasa surface view. 
“ 10. Stoma of oa rata—surface © view—passage beneath teeth shown by 


ee AeA ee 


dotted 1 
“11. Stoma of f "glauca—surface view 


“ 18. Assimilation oraria in longitudinal section of same. 


In Agave yuccefolia the cutinized layer of the epi- 
dermis is thinner and the air passage leading to the stoma 
proper is much shorter than the preceding and is 
elongated parallel to the long axis of the leaf (Figs. 3 


No. 497] ON XEROPHYTIC ADAPTATIONS 311 


FıG. 19. Groove in cross section of same—the cutinized portion of epidermal 
cell walls shown darker than other cell walls; mechanical tissue 


black. 
2 Cross section of leaf of s 
21. Cross section = ~ of een rp of same. 
* 22. Same after tw ars growth i p greenhou 
23. Part of cross pled of scars rs g agha aair 
“* 24, Part of cross section of leaf of Dasylerion Asatte "the middle of the 
leaf is filled with large asia storage tiss 
“* 25. Part of cross section of leaf of Agave ae a 


and 4). Beneath the cuticle is a thick layer of water- 
storing cellulose. A series of forms with this type of 
stoma arranged in order of progressive sinking of the 
stoma would include: Hesperaloe preciosa, Yucca de 
smetiana, Y. rupicola, Agave strida and Dasylerion 
texanum. In the last named (Fig. 5) the supra-stomal 
passage is divided into two dead air spaces, and the 
stomata occur in slight longitudinal furrows. The ridges 
between are braced heavily with mechanical tissue. 

In Agave americana, the century plant (Fig. 6), the 
sides my the elongated supra-stomal passage are produced 
into lips, constricting it in the middle. 


312 THE AMERICAN NATURALIST (Vou. XLII 


In Dasylerion wheeleri a second similar constriction 
occurs half way down this passage, so that in cross section 
it appears like Dasylerion texanum. In this species the 
epidermal cells are produced into papille. 

Going back to the simple type of stoma found in Yucca 
aloifolia we can trace variation in another direction. In 
the stomata of the lower side of the leaf of Yucca recurvi- 
folia the four sides of the supra-stomal passage are pro- 
duced into lips; those parallel to the long axis of the leaf 
being beneath the others (Figs. 7 and 8). On the upper 
side of the leaf the lips are not as well developed, and 
are all in the same plane, as are also those of Yucca 
australis and Y. treculiana. 

In Yucca radiosa (Fig. 9) and Y. constricta only two 
of the lips are developed, so that we have an opening 
somewhat like the ones in Agave americana rotated 
through a right angle. In Yucca rostrata the lips have 
developed so as to close the opening in the middle, leaving 
only an opening at each end (Fig. 10). 

In Y. glauca (Fig. 11) four additional lips have de- 
veloped above the two as in Y. radiosa, and the accessory 
cells have sunken considerably beneath the level of the 
other epidermal cells. 

In Agave victoria regina (Fig. 12) the presence of six 
lips is accompanied by the meeting of one pair and by the 
division of the supra-stomal passage into two dead air 
spaces (Fig. 13). Here the epidermal cells secrete an 
immensely thick layer of reserve or water-storing (7?) 
cellulose under the cuticle (Fig. 13). The leaf is very 
succulent and the vascular bundles are confined to the 
middle layer. 

In Agave schotti the shape of the supra-stomal passage 
changes greatly as we go inward. On the surface it is 
elongated at right angles to the long axis of the leaf, 
while farther down it is elongated parallel to the long 
axis (Fig. 14). 

Besides being sunken singly between the level of the 


No. 497] ON XEROPHYTIC ADAPTATIONS 313 


epidermis the stomata are often placed in rows at the 
bottom of a groove. These grooves are very slight in 
Nolina sp.? from Mexico (Fig. 15), Dasylerion wheeleri 
and D. texanum. They are deeper in D. glaucophyllum 
(Fig. 16) and Hesperaloe parviflora.2, They are very 
deep and guarded with teeth in Nolina texana? (Figs. 17 
and 18) and Nolina sp.? from West Texas. The forma- 
tion of grooves is directly associated with the bracing of 
the epidermis with beams of mechanical tissue (Fig. 20) 
along the ridges between the grooves. In Nolina sp.? 
from Mexico (Fig. 15), Dasylerion wheeleri (Fig. 24), 
D. texanum and Hesperaloe parviflora (Fig. 23) these 
beams are free in the interior of the leaf, but in D. glauco- 
phyllum and Nolina texana (Fig. 20) the beams of one 
side usually meet and fuse with those of the other, form- 
ing a rigid support for the epidermis that prevents any 
dorso-ventral shrinkage of the leaf on drying. The only 
shrinkage that does occur closes the grooves and thus is 
a further check to transpiration. Another characteristic 
associated with the presence of these longitudinal trans- 
piration grooves is a peculiar modification of the air 
passages in the assimilation tissue, which reaches its 
greatest development in the Nolinas. In the forms with- 
out grooves there is an irregular air space below the 
stoma, from which lead minute air spaces in all direc- 
tions. With the development of grooves is associated a 
more effective arrangement of these air spaces, so that 
rapid respiration of the deeper tissue is effected without 
the devotion of much of the volume of the leaf to air 
space. If we imagine the groove represented in Fig. 17 
in tangential section, as being placed horizontally with 
the opening upward, the assimilation tissue in the form of 
lamelle one cell thick is suspended from the inner surface 
of the groove. Air diffusing in through the stomata 
enters the narrow spaces between the lamellæ and almost 
immediately penetrates to the center of the leaf. If we 
* Bray, 703. 
* Bray, 703. 


314 THE AMERICAN NATURALIST [Von XLII 


imagine a lamella removed from the leaf when turgid, 
the cells composing it would be rounded on their free 
surfaces. If such a lamella were placed on another so 
that some of its cells rested on the apices of the cells of 
the one underneath, we should get a condition similar to 
that in Nolina texana (Figs. 18 and 19) and allied forms. 
Fig. 18 is drawn from a thick longitudinal section of the 
leaf, and the irregularities in the lamelle obscure their 
distinctness. The lamellæ are additionally supported by 
columns of elongated cystoliths running parallel to the 
long axis of the leaf and connecting one lamella with 
another. 

Mechanical and Vascular Tissue.—The leaves of Yucea 
and its allies are covered by a very thick cutinized epi- 
dermis which is quite stiff and supports the soft tissue 
beneath, thus forming an exoskeleton. In smooth leaves 
the bundles are distributed through the interior of the 
leaf, in thick leaves being arranged in several rows 
(Fig. 25). Each bundle is composed of vascular tissue 
supported by a large amount of mechanical tissue, and 
thus the bundles form an internal skeleton. In those 
leaves in which grooves occur the ridge between two 
grooves is heavily braced within with mechanical tissue 
(Fig. 23). These braces often extend inward until each 
fuses with a bundle (Fig. 23) and in some species all the 
bundles are attached to the inner edges of these braces 
(Fig. 15). In Dasylerion glaucophyllum and some 
species of Nolina (Fig. 20) the braces of one side of the 
leaf usually fuse in the middle with those of the other 
side, making a very rigid structure. 

Relation of Habitat to Structure of Stoma.—The com- 
plexity in structure of stoma in these forms lead Dr. Bray 
to suggest that I see whether there was any correlation 
between the structure of the stomata and the aridity of 
habitat. I found that there was in all except those that 
had the supra-stomal passage much elongated in the long 
axis of the leaf. Yucca aloifolia, Y. gloriosa and their 


No. 497] ON XEROPHYTIC ADAPTATIONS 315 


varieties have a supra-stomal passage nearly square in 
cross section (Fig. 1) that goes straight down to the 
stoma, and these species inhabit coast lands which, 
although hot, are humid. In Y. australis, Y. treculiana 
and Y. recurvifolia the supra-stomal passage is guarded 
by four lips (Fig. 7) and these species inhabit a region 
from the Gulf coast to the dry interior of the United 
States and Mexico. In Y. radiosa and Y. constricta the 
supra-stomal passage is closed in the middle (Fig. 9) and 
these species inhabit southern Arizona, western Texas 
and adjacent country. In Y. rostrata two widely sepa- 
rated openings lead into the supra-stomal passage (Fig. 
10), and we find this plant in the deserts of northern 
Mexico. In Agave victoria regina we find a similar 
structure with the addition of four small lips (Fig. 12) 
and we find this plant also in the deserts of northern 
Mexico (Coahuila). In Yucca glauca we find a structure 
similar to the preceding save that the two lower lips 
are slightly separated (Fig. 11), and this plant inhabits 
the slightly less arid lands from South Dakota to New 
Mexico and North Texas. In Agave schotti the supra- 
stomal passage is compressed in one axis (Fig. 14) anda 
little lower down is compressed at right angles to the 
first (Fig. 14, dotted line) and we find this plant in the 
deserts of southern Arizona. Finally, the Nolinas, whose 
stomata are placed in deep grooves guarded by inter- 
locking teeth, cling to crevices in the rocks in western 
Texas and northern Mexico, where not only is the air 
dry and the sun hot, but there is extremely little soil to 
hold a store of moisture. 

Development of Leaf in Nolina Texana.—The very 
young leaf in the adult plant is not deeply grooved as in 
Fig. 19 or 20 and the mechanical tissue is not well 
developed. The formation of grooves is associated with 
the formation of ribs of mechanical tissue supporting the 
epidermis between the bands of stomata, and by growth 
inward uniting with the vascular bundles, thus forming 


316 THE AMERICAN NATURALIST [Vou. XLII 


girders extending through the leaf in a dorso-ventral 
direction. The epidermis bulges out along the lines of 
attachment of the girders and sinks in between them. 
The epidermal cells bordering the grooves thus formed 
grow out into long interlocking teeth. The teeth get 
longer and the groove narrower as the leaf develops, thus 
protecting the stomata from the dry air. 

In the very young seedling the leaf is somewhat tri- 
angular in cross section (Fig. 21) with a vascular bundle 
in the center and one in each lateral angle and a bundle 
of mechanical tissue in the midrib. The epidermis is 
cutinized at this early stage. 

I kept a seedling in a greenhouse of the University of 
Pennsylvania about two years. The leaves did not grow 
stout as in plants from the natural habitat and I think the 
increased moisture and diminished insolation affected the 
thickness of the leaves (Fig. 22). The leaves were very 
thin; the mechanical tissue uniting with the vascular 
bundles formed beams connecting the dorsal with the 
ventral epidermis between the bands of stomata, but the 
grooves only began to develop. It seems remarkable that 
a plant so adapted to xerophytic conditions should be 
able so quickly to adjust itself to a moist atmosphere, 
and I think the subject merits further investigation. 


LITERATURE 
1903. Bray, W. L. ‘‘Tissues of some plants of the Sotol region.’’ Bull. 
Torrey Bot. Club, p. 30. 
1890. Drude, O. ‘‘Handbuch der Pflanzengeographie’’ (Die Drachen- 


umgruppe). 

1890. Gilson, E. ‘‘La suberine et les cellules du liége.’’ La Cellule, 
WA; P 99 

1903. Hansgirg. ‘‘ Phyllobiologie.’’ 

1903-1905. Karsten and Schenk. ‘‘ Vegetationsbilder.’’ Ser. 1, Pls. 28, 
33, 34, 46; Ser. 2, Pls. 19, 22, 59; Ser. 3, Pls. 25, 26. 

1895. Ludwig, F. ‘‘Lehrbuch der Biologie der Pflanzen.’’ 

1896. Mulford, A. I. ‘‘A Study of the Agaves of the U. S.’’ Rep. Mo. 
Bot. Garden, 796. 

1902. Trelease, W. ‘‘The Yucee.’’ Rep. Mo. Bot. Garden, no. 13. 


THE BIOLOGICAL LABORATORY OF THE BU- 
REAU OF FISHERIES AT WOODS HOLE, 
MASS.: REPORT OF WORK FOR 
THE SEASON OF 1907 


DR. FRANCIS B. SUMNER 


DIRECTOR OF THE LABORATORY. 


I. Recent ImproveMENts IN EQUIPMENT, Erc. 


1. Two rooms upon the third floor of the laboratory 
building have been reconstructed so as to serve 
for the reception of the specimens comprising the local 
reference museum. These last were moved from their 
former inadequate quarters at the commencement of the 
summer, and have been subjected to a thorough over- 
hauling. 

2. A considerable number of standard scientific works 
were purchased by the bureau as the nucleus of a per- 
manent reference library; though it is true that only a 
beginning has thus far been made. The already great 
collection of reprints and other miscellaneous donations, 
together with the reports of the scientific departments of 
this and other governments, has steadily increased. It 
was found, however, that the publications of many of our 
foremost American biologists were scarcely represented 
on the shelves of the library. With a view to remedying 
this serious lack, a circular was sent by the director to 
about three hundred American men of science, chiefly 
biologists, asking for contributioħs. A considerable 
number of these men responded liberally, and many hun- 
dreds of pamphlets and bound volumes have been re- 
ceived. It must be added with regret, however, that 
many others among those addressed have not yet thought 
it worth their while to place their writings in an institu 

317 


318 THE AMERICAN NATURALIST (Vor. XLII 


tion conducted solely for the public welfare, and offer- 
ing free facilities each year to a large number of biolo- 
gists. 

3. A steam drying apparatus was purchased, at a total 
cost of over three hundred dollars, for use in experiments 
upon the methods of preparing various marine foods. 
Owing to serious delay on the part of the manufacturers, 
this apparatus was unfortunately not installed until late 
in the season. 

4. Running fresh water was introduced into each of 
the large investigation rooms upon the second and third 
floors of the building, and enameled iron sinks were like- 
wise installed in these rooms. 

5. A contrivance was designed and constructed for the 
purpose of de-aerating the salt-water supply of the labora- 
tory and aquarium. 

6. The entire floor of the main laboratory room (162 
square yards) was covered with a layer of heavy linoleum. 

7. Electric table lamps, with parabolic reflectors, were 
substituted for the hanging lamps formerly used in the 
investigation rooms. 

8. The supply rooms for apparatus and chemicals were 
greatly extended, and many improvements were effected 
by carpentry throughout the building. | 


II. BROADER Lines or [NVESTIGATION 


1. Biological Survey.—Much progress was effected 
during the summer, as well as during the preceding 
winter, in the preparation of the report upon the bio- 
logical survey of local waters. It has furthermore been 
necessary to extend this work through the present winter; 
and the director is again in residence at Woods Hole, 
engaged in the completion of this project. At the present 
time it may be stated that the plotting of the distribution 
charts, several hundred in number, has been nearly com- 
pleted by Mr. J. W. Underwood; the compilation of an 
annotated list of the local fauna and flora (based both 
upon original observations and published records) is not ` 


No. 497] THE BUREAU OF FISHERIES 319 


far from finished; the physical data (temperature, ete.) 
are being tabulated; and preparatory steps are being 
taken toward the statement of generalized results and 
conclusions. During the summer it was found necessary 
to repeat the temperature and salinity determinations of 
preceding years. The steamer Fish Hawk was employed 
for this purpose and recently standardized instruments 
only were used. In this work the director was ably as- 
sisted by Mr. D. W. Davis. Careful thermometry re- 
vealed temperature conditions which do much toward 
explaining the distribution of certain forms of life, 
especially of those well-known boreal types which just — 
enter the region. This problem seemed of sufficient im- 
portance to justify another extensive series of tempera- 
ture and density determinations at the commencement of 
the present winter, and these have therefore been made 
by the director, with the assistance of the crew of the 
Phalarope. A third series of observations is contem- 
plated early in March; and possibly another at the com- 
mencement of the summer. 

The Fish Hawk was also employed in doing consider- 
able supplementary dredging; and the in-shore stations 
of Buzzards Bay, which, owing to an accident to the 
Phalarope, had been left unfinished in 1905, were now 
completed with the aid of the latter vessel. It is perhaps 
worthy of mention that the parasitic gastropod mollusk, 
Stilifer stimpsoni Verrill was taken for the first time 
(so far as recorded) in this region; and that the rare 
brittle star Amphioplus abdita (Verrill), which was re- 
cently made the subject of a special note in Science! by 
Dr. H. L. Clark, was dredged at no less than three 
stations. 

With one or two exceptions, all past collections derived 
from the dredging operations have been reported on by 
the specialists to whom they were referred. More than 
half of the catalogue of fauna and flora has been sub- 
mitted in manuscript form to these same taxonomic 

* January 24, 1908. 


320 THE AMERICAN NATURALIST [Vor XLIL 


experts for revision of nomenclature and other points. 
It is hoped that the entire report may be completed in 
the rough before the expiration of the coming summer. 

As usual, a fish trap was maintained in Buzzards Bay, 
at a point not far distant; and the customary seining trips 
were made for the supply of laboratory needs, as well as 
to furnish data regarding the occurrence of species. As 
a fact of especial interest in relation to the local fauna 
may be mentioned the entire lack, during the past season, 
of the gulf-weed, and the accompanying stragglers from 
tropical waters, which frequently form such a striking 
feature of the marine life during the latter part of the 
summer. 

2. Studies of Marine Foods.—Investigations have for 
several years been in progress, directed toward the utili- 
zation of certain marine organisms of apparently high 
food value, which have, notwithstanding, been hitherto 
neglected by our population. The ‘‘smooth’’ dogfish, the 
squid,? and the salt-water mussel have thus far received 
most attention at this laboratory. An arrangement was 
entered into with the ‘‘mess’’ of the Marine Biological 
Laboratory, whereby certain foods were prepared accord- 
ing to definite directions and served at certain of the 
dining tables. It was thus possible to obtain the opinions 
of a considerable number of persons as to the palatability 
of the articles in question. As already stated, a steam 
drying apparatus has been installed at this station as an 
important auxiliary to these experiments. Messrs. I. A. 
Field and C. L. Alsberg are engaged upon both the eco- 
nomic and the scientific aspects of this problem. Pro- 
fessor Field has already reported? upon certain features 
in the bionomics of the dogfish and some other unutilized 
fishes, but much work remains to be done, on both the 
industrial and the chemical phases of the subject. 

?It is here worth mentioning that two representatives of a Japanese 
produce establishment spent the summer on Cape Cod, taking steps toward 
the establishment of a plant for the drying of squid for exportation to 
their own country. 

* Bureau of Fisheries Document No. 622, issued 1907. 


No. 497] THE BUREAU OF FISHERIES 321 


3. Deaeration of the Laboratory Water Supply.—The 
‘‘oas disease’’ of fishes, especially as manifested in the 
aquaria at the Woods Hole station, has, in past years, 
been the subject of extensive investigations by Gorham 
and Marsh.t These two writers presented convincing 
evidence that the cause of this malady lay in the super- 
saturation of the salt-water supply with air. The latter 
was shown to be forced into solution under pressure, dur- 
ing the process of pumping, so that the water which 
passes into the distributing tanks is ‘‘charged’’ with air, 
in much the same manner as soda-water and other car- 
bonated beverages are charged with carbon dioxid. It is 
a familiar fact that such beverages quickly become ‘‘flat”’ 
if left to stand in an open vessel; and that the discharge 
of the gas is facilitated by agitating the liquid. Marsh 
found that in this principle lay a ready means of prevent- 
ing the troubles arising from the super-saturation of the 
Woods Hole water supply. If the water, before its 
entrance into an aquarium or fish tank, were allowed to 
splash through a perforated pan, or merely to fall from a 
height as a fine jet, the evils of the gas disease would be 
diminished or altogether prevented. This method has 
since been generally adopted at the laboratory in con- 
nection with the large aquaria employed for display pur- 
poses, as well as with the smaller ones used for scientific 
experiments. It has commonly been necessary to employ 
the smallest stream of water practicable, allowing it to 
fall from a height, and commonly causing it to pass 
through a perforated pan, or to trickle over a board or 
other flat surface. Indeed, there have frequently been 
occasions when a strong stream, introduced beneath the 
surface of the water in a small aquarium, would prove 
fatal within a day or less, even to hardy fishes. 

Such a state of affairs has obviously been a serious 
drawback to the work of the laboratory, which often 

* Bulletin U. S. Fish Commission, Vol. XIX (1899), pp. 33-37; Report 


U. S. Fish Commission for 1903 (1905), pp. 93-98; Report of the Bureau 
of Fisheries for 1904 (1905), pp. 343-376, pl. I-III. 


322 THE AMERICAN NATURALIST [ Vou. XLII 


demands that fishes shall be kept under observation, in a 
healthy condition, for days or weeks. Some method of 
treatment was deemed advisable which should be ap- 
plicable to the water supply as a whole. Thus far, no 
attempts to prevent the entrance of air into the pump, 
along with the water, have been permanently successful. 
The wooden suction-pipe, through which the pump 
formerly received its supply of sea-water, was replaced, 
early in 1903, by a metal one, the assumption being made 
that the porous condition of the former was responsible 
for the trouble. Indeed, Marsh and Gorham, writing 
during the following year, declare that ‘‘the replacement 
of the old suction pipe with a new impervious one 
abolished all signs of the gas disease at Woods Hole.’’ 
But the malady was again rife during the summer of 
1905, and has given much trouble during the seasons of 
1906 and 1907. In the absence of definite information as 
to the present source of the air in the water, the most 
promising mode of attacking the difficulty seemed to be 
the construction, on a large scale, of a deaerator, which 
should operate on the same principle as the pans and 
boards before employed for individual aquaria. Accord- 
ingly a series of five wooden trays was built, these lying 
in a zig-zag series, one above the other, and having a 
total bottom area of about 10,000 square inches, thus 
bringing a large surface of water into contact with the 
air. Perhaps the most effective factor in the case, how- 
ever, is the splashing of the water in its descent from one 
trough to the other and from the lowermost of these into 
the supply tank below. From the latter the water is 
distributed to the laboratory. 

This deaeration apparatus was not constructed until 
late in the past laboratory season, but the results of the 
tests already made seem well worth recording. The fatal 
effects of the water from the local supply had been con- 

spicuous throughout the summer. It may be mentioned, 
by way of example, that in one wooden tank in the hatch- 
ing room twenty ae died in a single day, apparently 


No. 497] THE BUREAU OF FISHERIES 323 


from this cause alone. In the display aquaria the fishes 
had fared pretty well, thanks to the use of perforated 
pans, which were suspended several feet above each tank. 
The water was in no case allowed to enter below the 
surface, as experience had shown that the result would 
have been disastrous. The deaeration apparatus was 
first put into use on August 31, and two days later the 
pans over these aquaria were removed, a full head of 
water being allowed to enter below the surface in each. 
This condition was maintained until September 23. Dur- 
ing this period of twenty-one days no deaths occurred 
beyond those occasional ones to be expected in a large 
miscellaneous collection of living fish. No symptoms of 
the gas disease were noted, either in the presence of sur- 
face ‘‘blebs,’’ or in the occurrence of ‘‘pop-eyed”’ fishes. 
The collection seemed in particularly good condition, and 
the absence of the splashing water overhead made it 
possible to keep the premises much more dry and neat. 
The natural inference from these facts was that the 
deaerator had fulfilled its requirements perfectly.. But 
before forming definite conclusions on this point, it was 
necessary to perform the control experiment of throwing 
the apparatus out of the circuit, and using the salt water 
just as delivered by the pump. This was done on the 
afternoon of September 23. The water supplying the 
aquaria was allowed to enter below the surface as before. 
On the following day (September 24) bubbles were noted 
upon the surface of some of the fishes, either in the mucus 
or beneath the epidermis. From records made through- 
out the ensuing twelve days, it appeared that out of 85 
fishes, belonging to 18 species, which were present at the 
time the process of deaeration was discontinued, 13, or 
more than 15 per cent., died within the ensuing six days; 
while within the first twelve days 15 others, or nearly 
18 per cent., manifested more or less marked symptoms 
of the gas disease. Almost exactly one third of the 
stock had accordingly been killed or obviously injured. 


324 THE AMERICAN NATURALIST [ Vou. XLII 


III. SEVENTH [NTERNATIONAL ZOOLOGICAL CONGRESS 

One of the prominent features of the program for the 
entertainment of the congress was a visit to Woods Hole 
on Sunday, August 25, when the members were welcomed 
jointly by the Marine Biological Laboratory and the 
Fisheries Laboratory. After a lunch served in the 
‘‘mess’’ hall of the former institution, the party was 
earried to New Bedford on the U. S. Fisheries steamer 
Fish Hawk. One drag with the dredge was made en route 
by way of demonstration. On the preceding evening an 
informal smoker was tendered by the research staff of the 
Fisheries Laboratory to the local scientific colony and to 
such of the foreign delegates as had already come to 
Woods Hole in response to a special invitation. Thirteen 
of these visitors’ were housed for the night in the resi- 
dence building of the station. A few of the most eminent 
of the foreign delegates, including Hubrecht, Bateson, 
von Graff and some others, had spent a week or more at 
Woods Hole prior to the visit of the congress; not, how- 
ever, as the guests of this laboratory. 


IV. INDIVIDUAL RESEARCHES 

Of the twenty-five or more persons employed in various 
capacities on behalf of the laboratory, thirteen may, from 
the nature of their work, be ranked as investigators, the 
others serving as assistants, janitors, ete. Fourteen 
volunteer (unpaid) investigators likewise held tables and 
carried on independent lines of research. These twenty- 
seven investigators represented 11 states and 21 educa- 
tional institutions,? ranging from New Hampshire to 
Michigan and Virginia. A detailed statement of indi- 
vidual researches is given below. 

The hospitality of the station was likewise extended to 
a number of gentlemen who are not strictly to be enrolled 

5 Messrs. Derjugin, Golovine, Heymons, Koshewnikov, Kusnezov, Le Souéf, 
Maximow, Metalnikoff, Nedrigoiloff, Samssonow, Wladimiroff and two 
others (record lost). 

Each being accredited to the institution in which he had taught or 

studied during the preceding academic year. 


No. 497] THE BUREAU OF FISHERIES 325 


among those conducting investigations in the laboratory 
during the past season. Among these are to be named 
the Hon. K. Gupta, of Bengal, who was making a study 
of American fisheries methods on behalf of his govern- 
ment; Messrs. G. Asaya and T. Miyake, who were seeking 
information in regard to the local occurrence of the squid; 
and Professors W. A. Locy, Henry F. Nachtrieb and S. P. 
Sigerfoos, who visited Woods Hole briefly at about the 
time of the zoological congress. 


Carl L. Alsberg, M.D., instrifetor in biological chem- 
‘istry, Harvard Medical School.—The greater part of Dr. 
Alsberg’s work consisted in the collection and prepara- 
tion for analysis of various marine animals which are 
either not used, or little used, as foods in this country. 
The complete analysis of such material was deferred until 
the winter months, when better facilities for analytical 
work would be available than it is possible to provide at 
Woods Hole. The work actually done at Woods Hole 
was to determine the water content of the different ma- 
terials, as well as the proportion of soluble proteid, ete. 
The other analyses are now being carried out in Boston. 
As a result of this work, it has become evident that in 
order to obtain reliable information concerning the food 
value of many of these forms it is necessary to study the 
extractives. As is well known, the extractives of ordi- 
nary meats have but little food value. For some of the 
lower forms, notably the dog fish, this is true to an even 
greater degree, because this fish contains large quantities 
of urea dissolved in the blood plasma and in the body 
fluids. In order to arrive at a correct estimate of the 
food value of such an animal, it is necessary to determine 
by accurate methods the urea content, and perhaps also 
that of the other extractives. Concerning the extractives 
of other forms at present under investigation, for instance 
the squid, nothing at all is known, and it will be necessary 
to make a study of them before we can estimate the food 
value of this mollusk. In addition to this line of work, 


326 THE AMERICAN NATURALIST [ Von. XLII 


which has immediate practical value, various other in- 
vestigations were undertaken, or at least the material for 
such investigations was collected. The study of the blood 
of the horse-shoe crab was begun, and two researches 
have been subsequently completed in Boston, both of 
which were presented at Chicago during the present 
winter, one before the American Society of Biological 
Chemists, and the other before the American Physio- 
logical Society. The first deals with the study of the 
blood-clot of this animal; the second started with a study 
of the enzymes of the serum and has led indirectly to 
interesting results concerning the guajac reaction of per- 
oxydases. Another investigation, the material for which 
was collected at Woods Hole, has also been finished sub- 
sequently. This is a study of the vitelline contained in 
the eggs of the spiny dog-fish. This vitelline has proved 
to be very similar to that which may be obtained from 
hens’ eggs. Finally, an examination was undertaken, 
but not yet completed, into the nature of the red pigment 
contained in the chromatophores of the skin of the squid. 


Charles B. Bennett, graduate student, Brown Uni- 
versity, (1) took part in the work of the biological survey, 
being engaged in a search for certain marine organisms 
concerning which additional data were required, (2) 
assisted Dr. Alsberg and Professor Field in some of the 
work above described. 


Walter B. Cannon, A.M., M.D., professor of physiology, 
Harvard Medical School.—The Movements of the Ali- 
mentary Canal in the Dog-fish. Peristaltic waves were 
seen to pass over the lower third of. the cardiae end of 
the stomach, but they did not pass on to the pyloric end. 
Along the narrow pyloric portion the waves were more 
frequent than on the cardiac portion. Three movements 
were seen in the spiral valve: (1) A segmenting move- 
ment, starting anteriorly as a constriction, which was 
replaced by a constriction one centimeter below, and this 


No. 497] THE BUREAU OF FISHERIES 327 


by another one centimeter below that, ete., until the whole 
intestine was traversed. When the series had passed 
three or four centimeters from the starting point, a new 
series began. (2) A movement starting posteriorly and 
passing forward, which consisted in a local shifting of 
the wall towards the left, i. e., clock-wise with reference 
to the axis of the valve viewed from behind. As shown 
by small holes cut in the wall, the shifting of the wall 
towards the left was accompanied by a shifting of the 
inner folds towards the right. . The effect must be a thor- 
ough mixing of the food between the two surfaces. 
(3) A large general shifting of the valve forwards, and 
with a right rotation through about 180°. This was 
caused by a great sheet of smooth muscle lying in the 
mesentery between the genital gland and the spiral valve. 


Joseph F. Clevenger, M.A., acting professor of chem- 
istry and biology, Wheaton College, Wheaton, Ill.— The 
Life History of Zostera marina and Ruppia maratima. 


Harold S. Colton, M.A., graduate student, University 
of Pennsylvania.—How ‘‘Fulgur’’ and ‘‘Sycotypus’’ eat 
Oysters, Mussels and Clams. The work, so far as per- 
formed at Woods Hole, consisted of a series of experi- 
ments and observations on the food of Fulgur and Sycoty- 
pus (Busycon carica and B. canaliculata), supplementing 
some which were begun at the University of Pennsylvania 
during the preceding winter. There had previously been 
no complete account of the taking of food by those gastro- 
pods. Stimpson (1860) and Ingersoll (1884) have men- 
tioned their food; the former not completely and the 
latter not correctly. The present studies dealt with the 
kind and amount of the food and their manner of taking 
it. (1) Although pieces of chopped oyster were found 
to stimulate these mollusks, the latter were never ob- 
served to eat them. B. canaliculata ate living Mya, 
Ostrea and Mytilus, but refused Venus. B. carica ac- 
cepted Mya, Ostrea, Mytilus, Modiolus, Ensis and Venus, 


328 THE AMERICAN NATURALIST [ Vou. XLII 


and devoured one of each. (2) It was frequently found 
that one individual ate two oysters or clams in a day; 
there usually being a long period of rest between meals, 
the animal remaining buried nearly all the time, some- 
times for as much as six weeks. (3) The character of the 
erosion, noticed on the odontophore, indicates that these 
mollusks are not shell borers. (4) When clams (Mya) 
are the objects of assault, no difficulty is encountered in 
gnawing out the soft parts, since the shells of the latter 
gape slightly. The mussel and oyster, on the other hand, 
are taken by surprise. The attacking gastropod thrusts 
the margin of its own shell between the valves of that 
of the prey, devouring the soft parts at leisure. In the 
ease of the ‘round clam’’ (Venus), B. carica uses yet 
another method of attack. Holding the bivalve in the 
hollow of its foot it brings the margin of its own shell 
against the margins of that of its prey. By the con- 
traction of the columellar muscle, the two are brought 
into such forcible contact that a small piece is chipped 
from the Venus shell. This is repeated many times, the 
process lasting from seven hours to three days, with the 
result that the crevice between the two valves is enlarged 
to such an extent that the gastropod can devour its vic- 
tim. (5) It is possible that the two species of Busycon do 
not inflict so great damage upon oyster or clam beds as 
has previously been reported. Field observations alone 
can settle this point, however. 


Edgar D. Congdon, M.A., Austin teaching fellow, de- 
partment of zoology, Harvard University, conducted in- 
vestigations upon the fauna of the brackish waters in the 
neighborhood of Woods Hole. A number of these ponds 
were studied intensively, collections being made of their 
fauna and flora, and determinations of density and tem- 
perature being taken. A series of other ponds was like- 
_ wise visited for purposes of comparison. Mr. Congdon 
also acted as librarian of the laboratory, and considerable 
time was devoted by him to classifying and cataloguing 


No. 497] THE BUREAU OF FISHERIES 329 


the now rather unwieldy collection of miscellaneous re- 
prints. 


Bradley M. Davis, Ph.D., past assistant professor of 
botany in Chicago University, finished during the summer 
the catalogue of the marine alge, together with a section 
of the report dealing with the distribution of alge and 
Zostera in the deeper waters of the bay and sound. Much 
of this manuscript had been written during the preceding 
spring, Dr. Davis having spent the months of April and 
May at the laboratory. The catalogue will contain more 
than 250 species of alge, with records of their distribu- 
tion and seasonal habits; and will include a list of the 
stations at which they were dredged. An introductory 
section on the general characteristics of the algal life of 
Buzzards Bay and Vineyard Sound has since been 
written, and the manuscript covering the botanical side 
of the survey is now practically complete, except for 
such editing as may be necessary to make the botanical 
and zoological portions conform in arrangement and 
style. An important part of the summer’s work in 
botany was the completion of maps showing the distribu- 
tion of 75 species of alge which grow in the deeper waters 
of the bay and sound. It is expected that the most im- 
portant of these maps will be published in connection 
with the catalogue, since they show, much more clearly 
than is possible in a mere description, the striking fea- 
tures in the distribution of the most characteristic 
species. 


Donald W. Davis, professor of biology, Sweet Briar 
College, Sweet Briar, Va.—(1) An Investigation of the 
Effects of Various Conditions acting at the Time of 
Impregnation upon the Size and Vigor of Fish Embryos. 
For the time being, attention was restricted to the effects 
of various temperatures, and Fundulus heteroclitus was 
selected for experimentation because of its convenient 
spawning period. Each lot of eggs, taken from a single 


330 ‘THE AMERICAN NATURALIST [ Vou. XLII 


female, was divided into equal parts. These parts were 
then fertilized by milt from a single male at tempera- 
tures differing from each other by 5°, 10°, 15° or 20° C. 
After a few minutes the two parts were again brought 
under identical conditions and so kept until hatching. 
At the expiration of a certain period, when practically 
all of the living embryos had hatched, all were fixed by 
the aceto-sublimate-formalin method, which was found 
to leave them well straightened. Careful records of 
mortality, rate of hatching, ete., in the different lots were 
kept. Measurements to be made upon the embryos, with 
a view to determining the tangible effects of such differ- 
ences in treatment, are not yet complete. (2) A study of 
the alleged interference in branchial circulation result- 
ing from the transfer of fishes from salt to fresh water, 
and vice versa, was also taken up. The conclusion of Bert 
and Mosso that such interference occurs in consequence 
of a clogging of the branchial capillaries by distorted 
blood corpuscles, was thought to be worth testing in view 
of recently published work by the director of the labora- 
tory upon some other effects of changes in salinity. The 
common smooth dog-fish (Mustelus canis), the scup 
(Stenotomus chrysops) and the killifish (Fundulus 
heteroclitus) were experimented upon, the first two named 
being species which succumb quickly when transferred to 
fresh water, while the last named is commonly able to 
survive for some days in fresh water. The hypothetical. 
clogging of the branchial vessels in these species was 
tested by passing physiological salt solution through the 
conus arteriosus at definite pressures, and the gills were 
then fixed for microscopical examination. Results im- 
mediately apparent revealed no such contrast as the state- 
ments of both Bert and Mosso would lead one to expect 
between fishes taken directly from salt water and those 
dying in fresh water. Further work will be necessary 
before a more definite statement of the results can be 
made. 


No. 497] THE BUREAU OF FISHERIES 331 


Irving A. Field, professor of chemistry and biology, 
Western Maryland College, conducted experiments, to 
which allusion has already been made, with a view to test- 
ing the food value of certain hitherto unused marine 
animals. These were tested in respect to their pala- 
tability and digestibility by serving them, properly 
cooked, to numerous persons, who passed judgment on 
the quality of the food and the effects subsequently ob- 
served. Determinations of the chemical composition and 
nutritive value of the materials in question were, as has 
already been stated, undertaken by Dr. Alsberg. Vari- 
ous methods used commercially for the preservation of 
fisheries products (drying, salting, pickling, ete.) were 
applied to the forms studied. Statistics relating to the 
abundance of each species and the cost of preparing it for 
the market were also kept. 


John H. Gerould, Ph.D., assistant professor of zoology, 
Dartmouth College, devoted a few days to the collection 
and study of a rare and hitherto undescribed species of 
sipunculid. Although two dredging trips were made 
with the Fish Hawk and the Phalarope for this express 
purpose, but a single specimen was obtained, which, how- 
ever, was observed in a living condition, an opportunity 
which was regarded as of considerable value. 


Charles W. Hargitt, Ph.D., professor of zoology, Syra- 
cuse University.—(1) A Monographic Synopsis of the 
Anthozoa of the Region. But little systematic attention 
has been devoted to the local representatives of this 
group since the work of Verrill and Smith more than 
thirty years ago. It has been the purpose of Dr. Hargitt 
to secure as full collections as the facilities at hand 
rendered possible, and to carefully review the group with 
reference to the species, their distribution, habits, de- 
velopment, ete. This work is now nearing completion so 
far as its laboratory phase is concerned, and will soon be 
ready for publication. Atleast one new species has been 


332 THE AMERICAN NATURALIST [ Vou. XLII 


found, and one or more have not as yet been identified 
with certainty. Some additional facts as to distribution 
and habits are likewise to be reported. (2) Systematic 
Determinations of Local Celenterate Animals, as related 
to the Biological Survey now in Progress. The survey 
has brought to light a number of new species of hydroids 
and medusx, and a few hitherto quite unrepresented in 
the fauna of the region. Some account of these may be 
found in some recent ‘‘Notes on the Celenterate Fauna 
of Woods Hole.” Others remain to be determined. 
Dr. Hargitt accompanied many of the dredging expedi- 
tions made, and thus personally collected most of his 
specimens in the living state, as they came up in the 
dredge. Opportunity was thus afforded for obtaining 
data as to color, ete., which are of much importance in 
such determinations. (3) The manuscript of the cata- 
logue of local fauna and flora, so far as this relates to the 
Coelenterata, was criticized and revised as to nomencla- 
ture. (4) Some living specimens of the fresh-water 
medusa, Limnocodium, were received from the Bureau of 
Fisheries. A brief notice of these has already appeared 
in Science (November 8, 1907). A fuller account of this 
most interesting medusa is ready, and will appear in the 
near future. 


George T. Hargitt, teacher of zoology, Syracuse (N. 
Y.) High School (now graduate student in Harvard).— 
Studies of the Embryology of the Hydromeduse. The 
work on the embryology of the cclenterates has been 
most often limited to two phases, viz., the place of origin 
of the germ cells and development of the medusa or 
gonophore; and the late cleavage of the egg, with the 
formation of the germ layers and the development of the 
planula and polyp. While attention has been so largely 
confined to the early cleavage and maturation of the egg, 
the results have been rather unsatisfactory and inconclu- 
sive, and often conflicting. The work under way is an 


7 Biological Bulletin, January, 1908. 


No. 497] THE BUREAU OF FISHERIES 333 


attempt to supply the missing or less known phases of the 
early development of the ccelenterate egg, and especially 
that of the Hydromeduse. 


John D. Haseman, M.A., graduate student, University 
of Indiana.—Studies of the Reactions of the Gastropod 
Litorina litorea to Stimuli. Experiments were con- 
ducted, both in the laboratory and in the field, with a 
view to determining the conditions and stimuli which were 
responsible for the movements of these mollusks and the 
positions chosen by them. It is believed by the writer 
that Mr. Haseman has already prepared for publication a 
paper embodying the results of these studies. 


William B. Herms, A.M., Ohio Wesleyan University 
(now fellow in zoology, Harvard University).—A Com- 
parative Study of Palemonetes. The habits, post-em- 
bryonie development and other facts in the natural his- 
tory of the common local prawn, Palemonetes vulgaris, 
were studied in relation to similar observations already 
made upon the related Palemonetes exilipes of Lake 
Erie. Interesting points, both of similarity and of differ- 
ence, were brought to light. A very close relationship 
between the two species undoubtedly exists. Several at- 
tempts were also made to acclimatize larve to higher 
and lower degrees of salinity. 


William E. Kellicott, Ph.D., professor of biology, 
Woman’s College, Baltimore.— Biometric Studies of the 
Dog-fish (Mustelus canis). The season was spent in the 
collection of data bearing on the general problems of 
correlation, growth, ete., in the dog-fish. A quite com- 
plete series of measurements, including about 30 char- 
acters, internal as well as external, was made upon about 
300 individuals. Dr. Kellicott is at present working 
over these data and examining into the rate of increase 
in weight of the brain and viscera. Some interesting 
facts have revealed themselves, and it is believed that a 
paper embodying these will be ready in the near future. 


334 THE AMERICAN NATURALIST [ Vou. XLIT 


Charles R. Knight, American Museum of Natural His- 
tory, New. York City, was engaged, as has been the case 
for several summers, in portraying pictorially some fea- 
tures of the local sea life. Mention may be made in 
particular of a tiger-shark (Galeocerdo tigrinus), and a 
dusky shark (Carcharinus obscurus). Of the latter, a 
specimen over ten feet in length was taken in the labora- 
tory’s fish trap, and was kept alive for a few days in the 
shark-pool belonging to the station. The lobster, blue 
crab and scup also received attention, a large canvas 
being devoted to a group of the last. 


Edwin Linton, Ph.D., professor of biology, Washington 
and Jefferson College.—(1) Besides examining such 
fishes as were available among those taken in the fish trap 
of the Bureau in Buzzards Bay, a preliminary study was 
made of a large amount of material from fishes and fish- 
eating birds, collected during the preceding nine months 
by Mr. Vinal N. Edwards. In agreement with the experi- 
ence of previous years was the fact that new habitats 
were found for species already known, and new or unre- 
corded species were added to the list of those previously 
known. Thus new species or new habitats were recorded 
for 21 species of fish. Adult specimens of Tetrarhynchus 
bicolor were encountered for the first time. They were 
found in the stomach of a dusky shark. Scoleces of this 
species had, however, been found in this and other hosts 
during previous years. The pigment which gives the 
characteristic color to the head and neck of this cestode 
was not dissolved by the killing fluid (chrom-acetic- 
formalin), and has not been decolorized by the aleohol in 
which the worms are preserved. (2) Of the pathological 
and diseased conditions which were noted, an interesting 
one is the case of an abnormal growth of the swim- 
bladder of a scup. This, when first seen, was a slender, 
white, vermiform object about two millimeters in 
diameter lying among the muscles of the side. It was at 
first thought to be a cestode, examples of which occa- 


No.497] THE BUREAU OF FISHERIES 335 


sionally penetrate the muscular tissue of their hosts. 
Upon tracing it forward, it proved to be a lateral pro- 
longation of the anterior end of the swim bladder. At its 
origin it corresponded in structure to the swim bladder, 
but at its posterior (i. e., distal) end it was rather firm 
and the walls were thickened. The alcoholic specimen, 
which has contracted somewhat, is 60 millimeters in 
length. (3) Butterfish were examined on five occasions 
for the flesh parasite described in the Bulletin of the 
Bureau of Fisheries.S The proportions of infected fishes 
were rather less than in previous years. (4) Consider- 
able attention was given to the parasites of the puffer 
(Spheroides maculatus) with a view to preparing a spe- - 
cial paper on the entozoa of that fish. (5) The prepara- 
tion was begun of tables of the distribution of the para- 
sites of fishes based upon collections made by Dr. Linton, 
at Beaufort, Bermuda, Tortugas and Woods Hole. These 
tables have since been completed and sent to the Bureau 
of Fisheries at Washington. (6) A beginning has also 
been made in the collecting of parasites from inverte- 
brate hosts for the purpose of securing stages in the life 
history of those parasites of fishes whose early stages are 
found in invertebrates. 


Albert J. May, A.M., instructor in the Boys’ High 
School, Reading, Pa., made observations upon the medusæ 
of various local hydroids, and collected material for 
future study. Corymorpha pendula, which was especially 
sought for, on account of obscure facts in its life history, 
unfortunately proved to be very rare. 


Hansford MacCurdy, Ph.D., professor of biology, Alma 
College, devoted most of his time to the study and tabula- 
tion of results obtained during the preceding summer 
relating to the hybridization of echi ms 


William J. Moenkhaus, Ph.D., associate professor of 
physiology, University of Indiana, continued studies, 
*Vol. 26, pp. 111-132. 


336 THE AMERICAN NATURALIST [ Vou. XLII 


begun some years ago, upon the hybridization of fishes 
belonging to widely separated genera and families. Such 
cross-fertilized eggs did not commonly hatch, or even 
develop far, but an interesting range of abnormalities was 
produced. A few experiments in cross-fertilizing cer- 
tain invertebrates were likewise undertaken. 


Raymond C. Osburn, Ph.D., instructor in zoology, 
Barnard College, Columbia University, was occupied 
chiefly in the preparation of a report upon the local 
marine bryozoa, basing this work for the most part upon 
collections made in the course of the biological survey 
during the past five summers. On account of the great 
abundance and almost universal distribution of many of 
these animals locally, the need of such a monograph has 
been much felt. Dr. Osburn has already found a con- 
siderable number of species which are new to the region, 
as well as discovering errors in the previous identifica- 
tion of certain common local forms. 


Jacob Reighard, Ph.D., professor of zoology, Univer- 
sity of Michigan, experimented upon certain features of 
the behavior of Fundulus heteroclitus; likewise compiled 
results obtained earlier in the summer at the Carnegie 
station at Tortugas, where experiments had been per- 
formed with the object of testing the alleged warning 
coloration of various brilliantly tinted tropical fishes. 


Russell Richardson, graduate student in the University 
of Pennsylvania (now assistant in the department of com- 
parative physiology, Harvard University).—Response of 
Limulus Muscle to the Electric Current. The two large 
lateral tail muscles were generally used. Both constant 
and interrupted (induced) currents were employed; and 
the stimulus was applied either by wires or by non- 
polarizable electrodes. Endeavor was made to find out 
whether there was more than one form of curve to be 
derived from induced shocks, as had been found by some 


No. 497] THE BUREAU OF FISHERIES 337 


workers; but all such attempts gave negative results, 
only one form of curve being obtained. The contraction 
is very rapid, and the height of the curve varies, within 
certain limits, as the strength of the stimulus. The re- 
laxation is rapid at first, but later takes place more 
slowly. Summation is more or less regular. With con- 
stant current there were generally obtained the usual 
stimulations at the make and break of the circuit. The 
form of the curves varied greatly, however, according to 
the direction in which the current traversed the muscle. 
The weak constant current caused a marked relaxation of 
the muscle, only when passing through it in an ascending 
direction. Fatigue in Limulus seems more or less 
regular. As it progresses, there is a noticeably greater 
interval between the contraction and the relaxation. The 
latter also becomes much slower. After this stage, the 
height of contraction gradually diminishes until no re- 
sponse at all is obtained. 


George G. Scott, A.M., instructor in biology, College of 
the City of New York.—(1)The Effect of Poisons, at Dif- 
ferent Temperatures, on Fundulus heteroclitus. Sixteen 
experiments are recorded. In each case two lots of fish 
were used, one lot being kept at the temperature of the 
laboratory, i. e., about 79° F., while the other lot was kept 
at a lower temperature, 7. e., about 50° F. Different 
dilute solutions of a variety of organic and inorganic 
poisons were used. In eleven of these experiments it was 
distinctly shown that the effect of the poison was greater 
at the higher temperature; in four, the result showed no 
difference; while in one, the result was opposite to the 
first named effect. (2) The Effect of Change in Density 
of the Water on the Blood of Fundulus heteroclitus. It 
has been recently shown by Sumner that there may occur 
a passage of fluids into or out of the bodies of teleost 
fishes when the density of the medium to which they are 
accustomed has been sufficiently changed. This has been 
proved by demonstrating the occurrence of changes of 


338 THE AMERICAN NATURALIST [ Vou. XLIT 


weight, and by other means. It seemed worth while to 
ascertain what effects, if any, such changes of water 
density have upon the blood. The results of a few 
typical experiments are here stated. Hzemacytometer 
determinations were made upon fishes subjected to dif- 
ferent conditions. The mean blood count of a number of 
specimens of Fundulus heteroclitus in natural sea water 
was found to be 2,700,000 red corpuscles per cubic milli- 
meter. Sea water contains about 3.5 per cent., by weight, 
of salts in solution. In an experiment in which the salt 
content of the water was increased to over 6 per cent. by 
the addition of sea-salt, the proportion of corpuscles had 
increased to about 3,500,000 per cubic millimeter. In the 
case of another lot of fishes which were placed in 1,500 
ec. of sea water, to which 30 grams of sea-salt had been 
added, it was found after six hours that the number of 
corpuscles was 2,800,000 per cubic millimeter. In yet 
another lot which were placed in 1,500 c.c. of sea-water 
plus 60 grams of sea-salt, the blood count, at the end of 
six hours, gave 3,000,000 corpuscles. In a case in which 
120 grams of sea-salt were added to 1,500 c.c. of sea- 
water the blood count gave 3,900,000 per cubic millimeter. 
A number of fishes were placed in sea water artificially 
strengthened to the point of containing about 9.5 per cent. 
of salts. After one hour it was found that the fishes 
had lost in weight, while the blood counts of two speci- 
mens averaged 2,800,000; at the end of two hours, a 
further loss in weight was noted in the remaining fishes, 
and in two specimens the average number of corpuscles 
counted, was now 3,434,000 per eubie millimeter. Fishes 
which were placed in distilled water and subjected to 
the hemacytometer test an hour and a half later yielded 
about 2,000,000 corpuscles to the cubic millimeter. In 
two experiments with distilled water there was at first a 
decrease in the number of corpuscles counted, then a 
gradual increase up to the normal, which increase later 
passed above the normal. The question as to whether or 
not the blood is diluted by the osmotic influx of water 


No. 497] THE BUREAU OF FISHERIES 339 


can likewise be investigated by determining whether the 
freezing point of blood serum from a fish which has been 
kept in fresh water is higher than that of blood serum 
from a fish taken from its normal medium. Although 
experiments of this sort had already been performed by 
a number of competent investigators, it seemed worth 
while to make the test again. This was impossible to do 
in the case of Fundulus on account of the small amount 
of serum obtainable. The experiment was carried out, 
however, upon Mustelus canis, the ‘‘smooth dog-fish.’” 
Five determinations were made with the blood serum of 
fishes taken from normal sea water, and five with blood 
serum of fishes that had been kept in fresh water for 
an hour. These experiments agreed in showing that the 
freezing point of serum from fishes kept in fresh water is 
much higher than that of fishes taken from sea water. 
It was thus demonstrated that the blood of fishes may be 
diluted by a sojourn in fresh water, and support is given 
to the view that the change in the number of corpuscles 
counted was due to dilution or concentration of the blood. 
The last mentioned experiment upon Fundulus, in which 
distilled water was used, suggests that after the first dilu- 
tion of the blood, due to the physical process of osmosis, 
there occurred a physiological reaction on the part of the 
organism, the excess of water being expelled from the 
blood. That it remains in the body of the animal, how- 
ever, is shown by the persistent increase in weight. 


Francis B. Sumner, Ph.D., director U. S. Fisheries 
Laboratory, Woods Hole, Mass.—(1) The supervision of 
the biological survey; (2) experiments in the deaeration 
of the local salt-water supply; (3) an investigation into 
the meaning of the color variations of Litorina palliata 
Say (carried on jointly with James W. Underwood). 
The first two of these lines of investigation have already 

been discussed in the more general part of the paper; a 


° The known physiological differences between elasmobranchs and teleosts 
can not, of course, be left out of consideration. 


340 THE AMERICAN NATURALIST (Vou. XLII 


synopsis of the third has appeared in a recent issue of 
Science’® and need not be repeated. 


James W. Underwood, student and assistant in Olivet 
College, (1) assisted in the work of the biological survey, 
being occupied for some months in plotting out the dis- 
tributions of the more frequent local species upon maps 
which had been printed for the purpose; (2) collected and 
studied the species comprising the local plankton during 
the spring season; (3) cooperated with the director in 
the above mentioned study of the color variations of 
Litorina palliata. 


Ralph E. Wager, A.M., teacher of biology, state 
normal school, Potsdam, N. Y.—Studies of the degenera- 
tive Changes in Hydroid Polyps under the Influence of 
Changed Polarity or Contact Stimuli. Experiments 
were performed for the purpose of providing material in 
different stages of degeneration, with the object of sub- 
sequently studying not only the histology, but more par- 
ticularly the cytology of the changes. Abundant ma- 
terial was at hand in the various species of Obelia, and a 
sufficient supply of the degenerating polyps was obtained 
to thoroughly test the killing and fixing methods, if not 
to satisfy the demands of the problem. Thereafter ex- 
periments were performed on Gonionemus for the purpose 
of obtaining regenerating tissues, with a similar intention 
of determining the cytological changes involved in their 
growth. Again a plentiful supply of material was avail- 
able, and enough of the regenerating tissues was obtained 
to make possible a fairly thorough study. 

March 27, 1908. 


HEREDITY OF HAIR-FORM IN MAN 


GERTRUDE C. DAVENPORT AND CHARLES B. DAVENPORT 


STATION FOR EXPERIMENTAL EVOLUTION, CARNEGIE INSTITUTION 
OF WASHINGTON, COLD SPRING HARBOR, N. Y. 


Tue hair of man shows various morphological types. 
Between straight hair, on the one hand, and woolly hair, 
on the other, there are all degrees of closeness of spiral. 
For convenience three intermediate grades may be recog- 
nized; wavy, having a very slight or open spiral involv- 
ing the entire hair from root to tip; curly, having a closer 
spiral involving the distal half of the hair; and frizzy or 
kinky, a close tight spiral of small diameter. Now, 
' although the conditions thus named are not discontinuous, 
they stand for types that are fairly well appreciated and 
distinguished popularly, so that in a random lot of people 
practically all would place a given sort of hair in the same 
category. 

These different types of hair form are associated with 
certain differences of the hair on cross section as well 
as in its method of growth. ‘Thus straight hair is 
nearly circular on cross section, while in woolly hair the 
cross section is elliptical and the long axis is to the short 
as 100: 40 or 100: 50. In wavy hair the proportions are 
as 100: 60 or 70. The straight hair of the Japanese has 
the proportions of 100: 85. 

Since the hair of most mammals is straight and pparty 
circular on cross section, we may regard this as the basal 
condition and the flattened hair as a specialized form 
marking an advance in the differentiation of axes. In 
addition to this difference in cross section hairs differ 
in the form of the hair follicle, which is in woolly hair not 
only flattened, but curved in an are through a quarter of a 
circle. ‘‘Emerging from an incurvated mould, it can only 

341 


342 THE AMERICAN NATURALIST [Vou. XLII 


continue to roll up outside, given especially its flattened 
shape; it rolls up into a spiral the plane of which, at the 
beginning, is perpendicular to the surface of the skin’’ 
(Deniker ’06, p. 48). As all gradations exist between 
straight hair and wool in other characters, so probably in 
the initial curvature. The intermediate nature of wavi- 
ness is probably due to an intermediate degree of curva- 
ture beneath the skin. This curvature of the follicle, 
again, is a departure from the usual mammalian condi- 
tion and is in the line of differentiation or advance. 

We are now in a position to formulate our problem. 
How do the more specialized types of hair form—much 
flattened and much curved woolly hair and slightly flat- 
tened, slightly curved wavy hair behave in heredity 
toward each other and toward the nearly cylindrical 
straight hair? 

The data for this study are derived from the same 
sources as those of our eye color study! and include the 
ancestral characteristics of about 500 children for two 
ascending generations. About 230 families are involved. 

The nomenclature of hair form that collaborators were 
requested to employ was as follows: Straight, wavy, 
curly, kinky. As our cards were distributed only among 
whites the term ‘‘woolly’’ was not used. The terms seem 
to have been, for the most part, understood by the 
collaborators. 

The first result revealed by an analysis of the pedigree 
data regarding hair form is that straight hair is recessive 
to the curved types. Thus to 70 pairs of parents both said 
to have straight hair were born 185 children of which we 
have records. Of these 167 are recorded as having 
straight hair; 13 ‘‘wavy’’ and 5 ‘‘eurly.’’ Also 164 
grandparents, both with ‘‘straight hair,’’ are said to have 
had 146 straight-haired children, 11 ‘‘wavy’’ and 7 
“curly.” Knowing how liable to slip collaborators are 
we venture to affirm that probably not less than 98 per 
cent. of the offspring of straight-haired parents have 

Science, N. S., XXVI, No. 670, pp. 589-592, November 1, 1907. _ 


No. 497] HEREDITY OF HAIR FORM 343 


themselves straight hair.? The genuine cases of straight- 
haired parents producing wavy or curly hair in the 
children are probably cases of imperfect dominance—or 
heterozygotes in which the recessive type appears to 
dominate. In all such cases the grandparentage contains 
always one or more cases of wavy or curly hair. Cases 
of recessive heterozygotes are not rare in the experience 
of students of heredity. They do not invalidate the 
general idea of Mendelian dominance. Striking cases of 
all straight-haired offspring of straight-haired parents 
are seen in the Bal., Bea., Bri., But., Cla., Hof., Loe., Mil., 
Oat., Pot., Reg., Sam., Spr. and Whe. families, each of 
four or more children. In these families there are 63 
children altogether, and all of them have straight hair. 

A second criterion of Mendelism is found in crosses of 
the R X DR type where a recessive is mated to a hetero- 
zygous dominant; in this case expectation is fifty per 
cent. of each type. Eighty matings between straight and 
heterozygous wavy give 61 straight and 52 curved-haired 
offspring, and 22 matings between straight and curly give 
53 straight and 38 curved; or altogether, 116 to 90 where 
103 of each is expectation (Cf. Dou-B., Got., Halz., Kar., 
McBr. families). There is a slight excess of recessives, 
probably due in part to a tendency to designate as 
“straight” boys whose curly hair is cut short; possibly 
to some cases of failure to dominate. 

A third criterion is found in the crosses of the 
DR X DR type where two heterozygotes are mated to- 

2 The principal sources of error in naming hair form made by our col- 
laborators are as follows: (1) Citing in males the form of the short, clipped 
hair instead of the youthful long hair. Curly hair when cut short appears as 
straight hair; this source of error is great in the case of the grandfathers, 
who are frequently deceased; (2) recording a hair form from a hazy 
recollection; a slightly wavy hair is often recalled as ‘‘straight.’? An 
attempt was made to get a confirmation of all doubtful cases (i. e., not in 
accordance with the law) and in almost all cases in which a reply was re- 
ceived one of the two ‘‘straight’’ parents of curved-haired children was 
found actually to have curved hair. One exceptional case is that of the 


344 THE AMERICAN NATURALIST [ Vou. XLII 


gether. Expectation in this case is 25 per cent. of the 
straight hair and 75 per cent. of the curved types—of the 
later 25 per cent. being pure dominants (DD) and 50 per 
cent. DR. Of 59 offspring of two DR parents there were 
actually found 22 per cent. curly, 51 per cent. wavy and 
27 per cent. straight, or 73 per cent. curved to 27 per cent. 
straight. This again accords closely with expectation 
and supports the view of the essential DR nature of wavy 
hair (Cf. Bar., Gav., Gen. families). 

All results indicate with a high degree of probability 
that straight hair is recessive to spiral hair; but it is 
probable that the spiral form may, in some cases, fail 
to dominate. 

We have now to consider the behavior of wavy in rela- 
tion to curly or kinky, i. e., the lesser grade toward the 
greater. The statistics show clearly that wavy hair is 
usually, if not always, a heterozygous condition, and not 
merely an intermediate stage that is recessive to a higher 
stage (curly) and dominant over a lower (straight). For 
straight by wavy frequently gives curly (10 per cent. of 
cases) as well as wavy and straight. The result is in 
close accord with the conclusion that wavy always carries 
both straight and curly germ cells and when mated with 
single yields in the offspring an equality of straight and 
curved hair. Thus 113 offspring of straight by wavy 
parents give 54 per cent. straight and 46 per cent. curved 
hair. The ‘‘curly’’ germ cell of a wavy-haired person, 
uniting with a ‘‘straight’’ germ cell, usually gives the 
heterozygous, wavy form; but in 23 per cent. of the cases 
fails to do so, owing, we may say, to the unusual activity 
of the curly determiner. Wavy appears also when the 
curly germ cells of a heterozygous curly-haired person 
unite with ‘‘straight’’ germ cells. As in the last case, 
the offspring are not all wavy; indeed, the proportion of 
wavy is less, for 53 per cent. of the offspring are curly. 
That peculiar strength which makes a heterozygote curly 
instead of wavy tends to make its heterozygous offspring 
also curly instead of wavy. 


No. 497] HEREDITY OF HAIR FORM 345 


We can now formulate the results of this study in their 
relation to human marriage, combining them in part with 
those obtained by us for eye color. Two blue-eyed, 
straight-haired parents will have only blue-eyed, straight- 
haired children. Two wavy-haired parents may have 
straight, wavy- or curly-haired children but the chances 
for curly hair are slight. Two curly-haired parents may 
have children with either straight, wavy or curly hair 
and the proportion of curly-haired offspring will prob- 
ably be large. When one parent has straight hair and 
the other curly hair the offspring will all have curly hair, 
if the curly-haired parent is homozygous—otherwise half 
of their children will have straight hair and half curved. 
But the families of straight and wavy haired parents will 
probably have straight as well as wavy and curly hair, 
for waviness is always heterozygous. 


346 THE AMERICAN NATURALIST 


[ Vou. XLII 


TABLE SHOWING eee ae oF HAIR FORM IN ALL FAMILIES OF Two 
R MORE CHILDREN. 


urly; s, straight; w, 


— means no recor 


wavy Letters in parentheses refer 
to paiio characters; when accompli by a ? the recessive character 
is inferred. Brackets are employed to designate inferred gametic consti- 
tution. ?? implies doubt whether the assigned character is correc 


Remarks. 


Mother’s sibs. : 
le, 1 w, 28: 


-5 
Mother’s sibs. : 
2w,l1s. 


T gan- Parents. Grandparents. Sapes 
os Nature of ia 
aS Mother’s|M ’s| 9 
$ 8 she g| Mother. Mating. | Mother. Faber: > & 
Pe |” | Father. Father’s carpal s| a1 £ 
| Mother. | Fath (E 
s 8 s 
Bal 6 s RXR |8 ce(s?) 6 
: | | w[es]} w[es] |s 
Bar -|3/2 1) e(s) DRX DR} s c 4.5 1.5 
s s s ; 
Bea 5 8 RXR |— s 5 
w[cs] ce(s?) | w[cs] 
Beh 161s DRXR |8 s 4 
s s s 
Bri 5 8 BME 8 8 5 
s s s 
But 4| s KX Es s 4 
c(s) s c 
Byr 42| |c DRXD | wies] ic 6 
8 s s 
Cam 1| 5| 4; w[cs] R Xx DR} s s?? 5 |5 
~ s s 
Cla 4| s Rx Hos 8 4 
“Es s c(s?) 
Davy 2| s RXR is s 2 
s s s 
Deg 1| 1| ce(s) Dx DR of pet s Se 
5 w[cs] |s 
Dou-A 2 5| ce(s) EXDRE ¢ s 3.5/3.5 
e(s) vfo c 
Dou-B |2 |2| s DRXR | wies] |s 2 |2 
w[cs] [8 s 
Dra 2 DEXD |c c 
s al ce(s?) 
Dru 2| w[cs] RX DR) w{es] 1 
s s w[es] 
Elt 11/1) e(s) RX DR, w[es] 1.5} 1.5 
s s w[es] 
Eny 1/8 w[cs] RX DR) s c 4.5) 4.5 
e(s) ce s 
Fal 16| s DEXRE i s 3.5/3 
w[cs] w[cs] | e(s?) 
Fis 2 11s DRXE | c(s) s 2 12 
s s s 
Fri 3| s RXBE |e s 3 
s s s 
Fue 3 e RXR is g 3 
: w[es od foe w[es 
Gav 24 1| w[cs DRX DR w{cs] | w[cs] | 5.3/1.7 
: c(s) 8 w([cs 
Gen 2 1| w[es] | DRX DR} s c 2.3) 0.7 
e(s) s e 
Gla |2 l4 o DRXDR| c s 5.31.7 


No. 497] HEREDITY OF HAIR FORM 347 


TABLE SHOWING INHERITANCE OF HAIR FORM IN ALL FAMILIES OF Two 
OR MORE CHILDREN.—Continued. 

lee s, straight; w, wavy. Letters in parentheses refer to recessive 

P ih when accompanied by a ? the recessive character is inferred. 

Brackets are employed to designate inferred gametic constitution. ?? im- 


plies doubt whether the assigned character is correct. — means no record. 
s : pein Parents. Grandparents. | ee 
23 Nature of 1g A Remarks. 
EF lols, Moner. | Mame | Moment Hemer” $| & 
re | Father. Father’s| Father’s| $ | £ 
Mother. | Father. | O | ù | 
w[cs] 8 c 
Gor 2 3/6) c(s) DRX DR) wies] | ¢ 8.2) 2.8 
s c (s?) | 8 
Got 2 2| w[cs] R XDR s w[cs] |2 |2 
w[e : i 
Gre 2| | w[ces] | DRX DR} w w[es] | 1.5 0.5 
w[cs] w[es] |s 
Hal, 2/1) 1) s DRXR | 8 w[es] |2 
s s s E fda curly 
Hal, 2 |2 at* RX DR) c s engrownlong] 
e(s) s 82? 
Har 3} 1) 6) s DEX Ris s 5 
E s w[es] |s 
Hil 3 | 8 TDRX ER is 1.5 1.5 
s s ce(s?) 
Hof 5s RXR a s 5 
s s 5 
Hop 2 s RXR |i s 2 
w[cs] s c 
Huf 2| 1| s DRXR | w[cs] |s 1.5/1.5 
w[es] 5 c . 
Hur 3/1) s DRXR js č 2 |2 
s s c 
Irw; 2| w[es] RX DR! s w[es}] |1 |1 
w[cs — — 
Irw, 1| 2| s DRXR | — — 1.5 15 
w[cs] s s? 
Jem 2/1) | s DRXR | w s 1.5 1.5 
w[es] s w[cs] 
Ker 111/2 s DRR la 8 2 
s s s Probably curl 
Koc 1 j4 a) w[es] |s |w. wes ones 
e(s c s 
Lat 4| |1 : DRXR is . 2.5 2.5 
s s s 
Loc, 5 au RX DR} e(s?) of J 2.5) 2.5 
w[cs c w[cs 
Loc, 2| s DRXR |s eu $i 
8 s c(s 
Loe 4) 5 RXR | s s 4 
S c 8 
McBr |2) 3| c(s) RXDR| s c 2.5) 2. 
s ce(s) s *[Probably curly 
Mea 1) 2) 1| s7* c js whengrownlong] - 
ś 8 8 8 
Mil, 3 s HxB 4 s 3 
. 8 8 8 
Mil, _ | | i8 s RXR |s s 6 


348 THE AMERICAN NATURALIST — [Vou. XLII 


TABLE SHOWING INHERITANCE OF HAIR FORM IN ALL FAMILIES OF Two 
oR MORE CHILDREN.—Continued. 
è; “athe s, straight; w, wavy. Letters in parentheses refer to recessive 


characters; when accompanied by a ? the recessive character is inferred. 
Brackets are employed to designate inferred gametie constitution. ?? im- 
plies doubt whether the assigned character is correct. — means no record. 
Sa ad Parents. Grandparents. a ane 
23 Nature of j chat a Remarks. 
2s Mother. Mating. Mother's! Mother’s| 3 a 
A TOMIE] Father. Fathers Father's Z £ 
Mother. | Father. | O | ~ 
8 w[cs] |s 
Moo 2| e(s) RXDR|s ? 1 
8 s ce(s?) *I er has 
Mor 2| w[cs] RXDR| — — 1 |1 || curly hai 
s* s EN E wre in man- 
Mur-B |1| |2 c(s)**| RXDR!/s s ?? *** | 1.5 1.5;< hood, 1 sister 
s — — has curly hair. 
Oat 8 RXR | — a 8 *** Recollec- 
w[cs] w[es] | w[es] tion hazy. 
Pad 5| | w[es] | DRX DR| — a: 3.8| 1.2 
o(s) . . * Confirmed 
Poe 3 ; DEE : s 1.5 1.5 by letter. 
Pot 4| ce(s?) RX DR} ce(s?) 2 
e(s) č w[es] 
Pre 141s DRX R | s 3 
8 w[es s 
Rau 2| s RXR js s 2 
s s s 
Reg 6, w[es] RX DR} s s 3 |3 
s , w[cs] |s 
Sam, 1| 1| ce(s?) RX DR| c eet) 1 i1 
ce(s) w[es] | s 
Sam, 3/2] + DEXR | 8 8 2.5) 2.5 
8 s s 
Sam, 5| 8 RXR 4 s 5 
s s > * [Probably 
Sco 1) |5| sr č s curly when 
s s 8 long.] 
Sho 3| s RXE is s 3 
s e a 
Spr 4| s RXR | — =- 4 
s s ` 
Sto-B 2| s RXR |s s 2 
s b. e(s?) 
Swe 3 s RXR is s 3 
w[cs] hd at s 
Tru 1| 1| 2| s | DRXR | wle] |s 2 2 
j wcs c E 
Tuc 1/1 d a DRXDR| w[cs] | wfes] 1.5 0.5 
s 8 ae 
Voo 3 8 RXR is 5 3 
w[es]} c  w[es] 
War-A |1|1| | wiles] | DRX DR) w[cs] |s 1.5 0.6 
s e(s?) |s i 
War-B 2| s BXR is s 2 
| 8?? e(s) s 
= Web 2' 5| s 8 


No. 497] HEREDITY OF HAIR FORM 349 


TABLE SHOWING INHERITANCE OF HAIR FORM IN ALL FAMILIES OF Two 
OR MORE CHILDREN.—Continued. 

urly; s, straight; w, wavy. Letters in parentheses refer to recessive 

characters; ; when accompanied by a ? the recessive character is inferred. 

?? im- 


ckets are employed to designate inferred gametic constituti 
piia doubt whether the assigned character is Sige: — means no record. 
m oe Parents. Grandparents, on tg 
Ll 
ms Nature of : apels Remarks. 
2 Moth Mother’s Y | S 
S3 | clwle| Momer.| Mating. | Hotter’ Tatmer | È | & 
2 (5| Father. Father’s Father’s| $| £ 
| Mother. | Father. | O | & 
| w[es] s s? 
Wel 3/7] s DRXR |— c 5]5 
S S s 
Wet Za ESR lk s 2 
S — — 
Whe, 6s RXR ! — — 6 
ce(s?) — — 
Whe, His DEXR i4 S beled 
s 5 s 
Wil, 3 s RXR | s s 3 
; s s 8 | 
Zim 21 s BXR 4s we eee ee 2 | : eae 
Total 110 202 123 189 


NOTES AND LITERATURE 
ECHINODERMATA 


Renewed Interest in Recent Crinoids.—Since the lamented death 
of Dr. P. H. Carpenter in 1891, the recent crinoids have received 
little attention as compared with the other classes of echinoderms. 
Aside from the obvious difficulty of securing material, this has 
been due to certain inherent difficulties which systematic work in 
this class affords. Carpenter and his successors have recognized 
but few genera, the largest of these being cosmopolitan in dis- 
tribution, and the numerous species have appeared to be ill- 
defined and extremely variable. Consequently aside from A. 
Agassiz’s great monograph on Calamocrinus, a few systematic 
papers by Hartlaub, Bell, Koehler, Döderlein and Chadwick, 
a monograph on Antedon bifida, by the last, and an important 
morphological paper, on arm-regeneration in Comatulids by 
Minckert, our knowledge of the recent crinoids, and particularly 
our understanding of the interrelationships of the subordinate 
groups, was, at the beginning of 1907, about where it was left by 
Carpenter nearly twenty years before. The cruise of the ‘‘ Alba- 
tross’’ in the North Pacific in 1906 afforded one of her natural- 
ists, Mr. Austin Hobart Clark, exceptional opportunities for the 
study of recent crinoids and recognizing the responsibility thus 
laid upon him, Mr. Clark has during the past year made numer- 
ous and important contributions to our knowledge. 

His first paper, ‘‘Two New Crinoids from the North Pacific 
Ocean,’’+ gives a figure and description of a most remarkable 
new stalked crinoid, for which the name Phrynocrinus is pro- 
posed, and of a new species of Bathycrinus, a well-known deep- 
sea genus of stalked crinoids. So remarkable does Phrynocrinus 
appear to be that it is suggested a new family, ‘‘ Phrynocrinide,’’ 
be established for it. The characters of this family are un- 
fortunately not suggested, and to one having only an indistinct 
idea of the characters upon which the already very large num- 
ber of families (mostly extinct) of stalked erinoids is based, 
the proposal of a new family does not make a strong appeal. 

On the same date, Mr. Clark published a paper on ‘‘A New 

1 Proc. U. S. Nat. Mus., 32, pp. 507-512. 


No. 497] NOTES AND LITERATURE 351 


Species of Crinoid (Ptilocrinus pinnatus) from the Pacifie Coast, 
with a Note on Bathycrinus,’’? in which another remarkable 
genus of stalked crinoids is described and figured, and there is 
a discussion of some of the specific names used in Bathycrinus. 
The new genus is considered to be related to the interesting Cal- 
amocrinus which the ‘‘ Albatross’’ collected some years ago near 
the Galapagos Islands. 

A paper on ‘‘Crinoids of the Genus Eudiocrinus from Japan’’* 
bears the same date as the two preceding. Eudiocrinus is a 
genus of free-swimming crinoids (comatulids) remarkable for 
having united radials, but only five arms. Two species were 
found to be common along the southern coast of Japan, and three `‘ 
specimens of a third, which is described as new, were also taken 
by the ‘‘ Albatross.” A summary of the genus, with a synonymy 
of its seven species and statements of the type-localities closes 
the paper. Two papers dealing with ‘‘New Species of Recent 
Unstalked Crinoids’’* appeared in September and give us a 
little insight into the extraordinary wealth of material which 
the ‘‘ Albatross’’ collected, for we have here descriptions of no 
less than 55 new species, of which 52 belong to the genus Ante- 
don as used by previous writers. Mr. Clark points out that the 
- commonly used generic name Actinometra is untenable, being a 
pure synonym of Lamarck’s older name Comatula. As the free- 
swimming crinoids are now so commonly called comatulids, it is 
not an unwelcome discovery which thus rehabilitates Comatula. 
Free use is made of artifieial keys in these papers, although their 
usefulness is impaired by their doubtless necessary limitation to 
the new species and two or three most nearly related forms. 
There is plain intimation that Carpenter’s ‘‘groups’’ of the 
genus Antedon are not in all cases natural or satisfactory divi- 
sions and that a rearrangement of the species is necessary. 

In his next paper, ‘‘New Genera of Recent Free Crinoids,’’> 
Mr. Clark attacks this problem and shatters the old genus Ante- 
don into eighteen fragments, entirely discarding the group ar- 
rangement of Carpenter. At first thought this seems like need- 
lessly drastic treatment, but the more one studies Mr. Clark’s 
reasons and results, the more satisfied one becomes that such 
treatment is unavoidable if we are to get at the true interrelation- 

* Proc. U. 8. Nat. Mus., 32, pp. 551-554. 

*Proc. U. 8. Nat. Mus., 32, pp. 569-574. 

* Proc. U. 8. Nat. Mus., 33, pp. 69-84 and 127-156, 

* Smith. Mise. Coll., 50, pp. 343-364. 


302 THE AMERICAN NATURALIST [ Vou. XLIT 


ships of the comatulids. Few zoologists realize how many species 
of recent comatulids are now known, and it may therefore be of 
interest to point out that while only four of the new genera 
proposed are monotypic, five have more than eighteen species 
each and one of these has over fifty. Mr. Clark’s selection of 
new names for his genera is particularly to be commended, as all 
are derived from the Greek, terminate in -metra, and are eu- 
phemistic. 

During the summer, Mr. Clark worked at the Museum of 
Comparative Zodlogy and some of the results of his work ap- 
peared in January in a paper, entitled ‘‘Notice of Some Crinoids 
` in the Collection of the Museum of Comparative Zodlogy.’’® In 
addition to the description of eight new species, there is an im- 
portant note on six-rayed crinoids, a key to the genus Bathy- 
erinus in which eight species are recognized, a table showing the 
bathymetrical and geographical distribution of Bathycrinus, and 
finally a ‘‘Key to the genera of Antedonide.’’ This key is an 
enlargement and slight rearrangement of the one published in 
October and includes two additional genera, both of which seem 
to be well-defined. 

Not content with systematic work alone, Mr. Clark shows his 
interest in crinoid morphology, and the larger questions involved 
when the geological history of the class is considered, by a very 
important paper on ‘‘Infrabasals in Recent Genera of the Cri- 
noid Family Pentacrinitide,’’* in which he demonstrates, ap- 
parently beyond doubt, the presence of infrabasals in Isocrinus 
decorus and Metacrinus rotundus. As no less an authority than 
Carpenter himself ‘‘ positively asserts that they do not exist in 
the recent Pentacrinitide,’’ this discovery is very interesting. 

Having found how heterogeneous a group the old genus Ante- 
don is, Mr. Clark’s attention was naturally turned next to the 
equally well-known genus Comatula, and the results are given 
in ‘‘The Crinoid Genus Comatula Lamarck; with a Note on the 
Encrinus parre of Guérin.’’® It is interesting to know that 
Comatula is far more homogeneous than might have been ex- 
pected and requires the coinage of no new generic names and the 
revival of only a single old one, Comaster. The latter however, 
ineludes 43 of the 50 species hitherto called Comatula (or Actino- 
metra). The note on Encrinus parre is important and interest- 

° Bull. M. C. Z., 51, pp. 233-248. 

1 Proc. U. 8. N. M., 33, pp. 671-676. ; 

$ Proc. U. 8. N. M., 33, pp. 683-688. 


No. 497] NOTES AND LITERATURE 353 


ing for it clearly shows that the familiar name Pentacrinus 
miilleri, which has been used for a well-known West Indian eri- 
noid for over half a century must give way to the combination 
Isocrinus parre (Guérin), the specifie component of which ante- 
dates miilleri by over twenty years. 

Although the genus Antedon of previous writers had already 
yielded him nineteen new genera, Mr. Clark’s indefatigable la- 
bors convinced him that the residue left therein (some 36 species) 
was not a homogeneous or natural group. In his ‘‘New Genera 
of Unstalked Crinoids,’’® he has analyzed it and resolved it into 
thirteen elements, three of which are monotypic and three con- 
tain only two species each. Although he names his new genera 
with his customary skill and euphony, and gives the genotype 
and other species of each, he does not tell us what is left for 
Antedon s. str., and if we attempt to figure it out for ourselves, 
we reach the remarkable conclusion that Antedon as now limited 
contains minus 7 species! For, in October Mr. Clark said that 
Antedon (in the restricted sense in which he then used the name) 
contained 36 species. Since October he has described two addi- 
tional species, which would give him 38 species for the new 
genera described in April. But these 12 new genera contain a 
total of 45 species, and therefore Antedon s. str. must now have 
— 7 species! Whether this discrepancy is due to the shifting 
of the limits of some of his earlier genera, or to species of other 
writers which he had previously overlooked, or to nomina nuda 
introduced in the paper under discussion, we shall leave to Mr. 
Clark to explain at some future time.—Besides his new genera 
of Antedonide, Mr. Clark splits Eudiocrinus into two genera 
which he considers fundamentally distinct, and he then proposes 
no less than eight families of comatulids, with 39 genera. As he 
gives no definitions, or even a key, to these families, we can not 
express an opinion as to their validity. We can only wonder if 
Mr. Clark’s enthusiasm is not leading him to magnify relatively 
unimportant details into significant morphological differences, 
and blinding him to the fundamental similarities of structure 
which the Antedonide show. 

The ten papers here reviewed are sufficient to convince any one 
that their writer is a worker of extraordinary industry and en- 
thusiasm. More than this, however, they give promise that Mr. 
Clark is to become a worthy successor to Carpenter as an au- 
thority on recent crinoids. Situated where the great collections 

? Proc. Biol. Soc. Wash., 21, pp. 125-136. 


354 THE AMERICAN NATURALIST [ Von. XLII 


of the National Museum, which, thanks to the ‘‘ Albatross,’’ prob- 
ably contain the largest and finest lot of crinoids in the world, 
are constantly available, his opportunities are most unusual and 
it must be a source of pleasure and gratification to all students 
of echinoderms that he is living up to them so well. His work 
reveals unusual powers of analysis and of skill in making his 
distinctions tangible, as witness his artificial keys to genera and 
species which seem to be very usable. He is quick to see a new 
point in structure or a new interpretation of some point already 
known, and while he treats the work of Carpenter and other 
writers with the courtesy and consideration they deserve, he does 
not hesitate to point out errors or misinterpretations which they 
have made. If he possesses the necessary patience and per- 
sistence, there is every reason to believe that Mr. Clark’s work 
will prove epoch-making in the history of crinoid morphology and 
taxonomy. 

Two faults seem to the present reviewer to mar Mr. Clark’s 
work so far, and it is greatly to be hoped that he will have the 
courage and self-control to eliminate them in the future. One is 
a tendency to rush into print on the discovery of each new fact 
or group of facts, and the consequent result is a multiplication 
of titles to afflict all future workers, and a decided weakening of 
the value of each of his papers. Had Mr. Clark made four 
papers out of the ten which have already appeared, not only 
would bibliographers have blessed him, but his work would at 
least seem to have more of the weight and dignity which its 
quality shows it to deserve——The other fault is a far more 
serious one and appears to be the cause of whatever errors and 
ambiguities mar Mr. Clark’s work. It is hastiness in reaching a 
conclusion, hastiness in grouping the conclusions reached and 
hastiness in preparing his results for the press. In a word, 
haste is Mr. Clark’s besetting sin and threatens to be the source of 
much quite avoidable trouble. As an illustration of what is 
meant by this criticism, reference may be made to some points 
in Mr. Clark’s paper, ‘‘New Genera of Unstalked Crinoids.’’ 
In his introductory remarks, he corrects four or five slight errors 
in his earlier papers, all of which might fairly be said to have 
been caused by haste. Under Thaumatometra, ‘‘ Antedon ciliata 
A. H. Clark, 1907 (= Antedon tenuis A. H. Clark, 1907),’’ is 
given as the genotype, but neither ciliata nor tenuis appear in 
the list of species referable to the genus. Moreover, if we go 
back a little we find that while tenuis and ciliata were described 


No. 497] NOTES AND LITERATURE 355 


in September, in October Mr. Clark substituted the name stella 
for tenuis as the latter is preoccupied. Now are we to under- 
stand that Mr. Clark has concluded his three names refer to a 
single species? If so the description of tenuis and ciliata as dis- 
tinct species was, to say the least, hasty. Again, under Comp- 
sometra, we find the following bit of evidence of haste in prepa- 
ration: certain characters ‘‘ distinguish this species at once. The 
two species at present known are,’’ ete. Evidently the first ‘‘spe- 
cies’’ should read ‘‘genus.’’ Under Isometra, Mr. Clark says 
that the name challengeri which he bestowed on an Antedon in 
1907 is a synonym because it was given ‘‘before its relation to 
angustipinna was detected.’’ Under Pentametrocrinus attention 
is called to an important morphological feature of certain species 
of Eudiocrinus, which ‘‘seems to have escaped the notice of all 
subsequent workers,’’ and yet Mr. Clark himself published, less 
than a year ago, quite a paper on Eudiocrinus, with description 
of a new species and an annotated list of all previously known 
ones. Finally, in concluding his paper, Mr. Clark says, ‘‘The 
genera of free crinoids belonging to the Comatulida may be 
grouped as follows,’’ and he then gives eight families with their 
various genera. But we fail to find the Atelecrinide or the 
genus Atelecrinus mentioned, and we can only guess whether the 
genus is considered synonymous with one of those given (which 
hardly seems possible) or is omitted through carelessness. Now 
while it is true that none of these slips is serious, Mr. Clark has 
not hesitated to criticize other writers for very similar blunders, 
and their presence in his work necessarily affects our estimate of 
its reliability. It is of the greatest importance, if the mantle of 
Carpenter is to rest becomingly on his shoulders, that in his 
future work, Mr. Clark reveal a greater patience, a more con- 
trolled enthusiasm and a more painstaking care in the prepa- 
ration of his results for publication. 
HKG 
ANIMAL BEHAVIOR. 

Recent Work on the Behavior of Higher Animals.—The members 
of the genus Mus—the rats and mice—seem in a fair way to 
become the classic animals for comparative psychology, as the 
frog has long been for physiology. The work of the Harvard 
school, examined in our last review, dealt largely with these ani- 
mals. The recent work of the Chicago laboratory is concen- 
trated even more precisely on the white rat. 


356 THE AMERICAN NATURALIST [ Vou. XLII 


In his earlier work on ‘‘ Animal Education,’’ Watson had made 
such a general study of the behavior of the white rat as to 
give a survey of the problems and methods for future work. He 
and his collaborators have now undertaken a _ well-considered 
campaign of intensive investigation in the different phases of 
the rat’s behavior. 

The matter selected for first attack is ‘‘the determination of 
the relative importance of the several sensations of a given ani- 
mal in its adjustment to its environment.’’ What senses does the 
rat use in finding its way about and what part does each sense 
play? To this is devoted the main recent work from the Chi- 
cago laboratory.’ 

Watson finds, as Yerkes did with the dancing mouse, that the 
rat makes comparatively little use of senses that we are accus- 
tomed to think of as the all-important ones. His conclusion 
that sight, touch, hearing and smell play little, if any, part in 
the rat’s finding its way about may almost receive the usual 
reportorial characterization of scientific results as ‘‘startling.’’ 

The method of work was to place the rat at the entrance of 
the complicated ‘‘ Hampton Court’’ maze, with its many passage- 
ways and blind alleys, and allow it to find its way to the central 
compartment, where food had been placed. This was repeated 
many times, till the correct path was completely learned; many 
different rats were used, and a thorough study was made of the 
rat’s method of finding its way. The questions are essentially, 
(1) what senses does the rat use in learning the correct path; 
(2) what senses does it use in following the correct path after it 
is learned ? 

To answer these questions, one or more senses were excluded, 
in different specimens, either by operative procedure or by other 
methods. The following extraordinary results were reached: 

1. Blinded rats, or those studied in complete darkness, learn 
the path as quickly and follow it as readily as do those that 
ean see. Even if the path is learned in the light, blindness causes 
no disturbance in later following it. (One rat formed an excep- 
tion, finding its way in the dark only with the greatest difficulty.) 

2. Rats deprived of smell and of hearing do not differ from 
normal ones in learning and following the correct path. This is 
true even when these rats are likewise blinded. 

1 Watson, J. B. Kinesthetic and Organice Sensations: their Rôle in the 
Reactions of the White Rat to the Maze. The Psychological Review, Mon- 
ograph Supplement, Vol. 8, No. 2, 1907, 100 pages. 


No. 497] NOTES AND LITERATURE 357 

3. Removal of the long vibrisse or ‘‘feelers’’ on the face at 
first disturbed the rats greatly. But if, before testing them with 
the maze, the rats were allowed forty-eight hours to become ac- 
customed to the loss of the vibrissx, then they threaded the maze 
as readily as did normal rats. This was true even if these same 
rats were blind or without smell. 

4. Altering the temperature conditions, changing the air cur- 
rents in the maze, or making the feet insensitive does not disturb 
the rats, so that the corresponding senses seem to play no part 
in the behavior. 

5. The evidence is strong that taste plays no part in the 
matter. 

Apparently then we can exclude sight, touch, smell, hearing, 
taste and the temperature sense as factors of any importance in 
finding the way through the labyrinth. How then does the 
rat find its way? 

Evidently the rat relies for its guidance mainly on the com- 
plex of inner sensations due to its own movements, the amount 
of effort it has put forth, and the like; the ‘‘kinesthetie and 
organic sensations.’ In threading the maze, the animal learns 
how much effort it is to put forth going in a certain direction, 
which way and how much it is then to turn, how much effort to 
put forth in the new direction, which way to turn again, ete. It 
finally knows the entire path as a combination of such efforts and 
turns. The behavior of the rat is somewhat like that of a person 
who may, in the dark, walk about a house with which he is 
familiar, threading his way among tables and chairs, without 
touching them. But in man this involves many memory images 
of the various objects and their relative positions and distances. 
In the rat such images evidently play little if any part; it is 
mainly a matter of amount of effort, direction of turn, and the 
like. Watson is inclined to conclude that the rat has no such 
images; that the purely intraorganic sensations account for the 
entire behavior; that the rat uses in threading the maze no sense 
data from the outside, either past or present. 

If this is true, then if the trained rat could be started at the 
entrance of the maze so as to get the proper ‘‘cue’’ at the 
beginning, and then the entire maze lifted from the floor, so as 
to leave a clear space to the food in the center, the rat ought 
nevertheless to follow the same complex path that it follows when 
the walls of the maze are present. Would this occur? Could 

‘not the experiment be tried? 


358 THE AMERICAN NATURALIST [ Vou. XLII 


While it appears conceivable that the running of the maze, 
after it is learned could be exclusively a matter of the inner 
sensations, so that the rat might follow the path even if the maze 
were absent, it is extremely difficult to see how this could be the 
case with the first learning of the maze. Our proposed ex- 
periment of removing all source of ‘‘extraorganic’’ sensation by 
doing away with the walls of the maze seems a reductio ad ab- 
surdum; the rat certainly would not learn the typical maze path 
under such conditions. How does the rat learn that it must 
put forth so much effort in a certain direction, then turn in a 
certain way? It would seem that for this, certain data from 
outside,—due either to feeling the wall with vibrisse, or run- 
ning squarely against it, or the like—are necessary. Even when 
the rat runs full tilt against a wall, that gives some sort of an 
extrinsic sensation that would seem to require consideration. 

This is a point which the author does not make clear, though 
he seems to argue decidedly that it is possible to explain the 
entire behavior, both in learning and in finding the way after it 
has been learned, from the purely inner sensations. Does he 
perhaps hold that the only effect sensed by the rat, when it runs 
against a wall, is one of restraint, of prevention of further effort 
in that direction? Such a view would seem possible, if at all, 
only for actual collision at full speed, while cases where the rat 
merely feels the wall with its vibrisse seem hardly open to this 
interpretation. It would have been helpful to certain readers if 
the author had so far recognized their obtuseness as to take up 
this point explicitly. In passing it may be remarked that the 
entire paper is written in a curiously confused and careless man- 
ner, as if it were a first draft which the author had not found 
-time to revise. So thorough and important an investigation de- 
served better treatment. 

A further development of the work set forth in the paper of 
Watson is presented in a later paper by Carr and Watson.2 _ 
If the rat’s method of threading the maze is merely to go a 
certain distance (as measured by the amount of effort put forth) 
then to turn in a certain direction, ete., without any data from 
outside itself, then evidently it would be greatly disturbed by 
altering the lengths and proportions of the passageways. Or if 
it is set down not at the entrance to the maze, but in the middle 

? Carr, Harvey, and Watson, J. B. Orientation in the White Rat. 
Journ. Comp. Neurol. and Psychol., 1908, 18, 27-44. 


* 


No. 497] NOTES AND LITERATURE 359 


of one of the passages, of course a different combination of move- 
ments will be required to reach the center; a combination which 
it will not have learned, so that confusion would result. On 
the other hand, if the rat recognizes the correct turns, ete., by 
sight or other extraorganic senses, then less confusion need re- 
sult from the changes mentioned. 

The paper of Carr and Watson is an account of the behavior 
of the rat when the alterations above mentioned are made. en 
the trained rat is placed, not at the entrance of the maze, but in 
one of the passages, it appears confused, wanders about, then 
suddenly gets a ‘‘cue,’’ and runs directly along the correct path- 
way to the center. The authors argue that the animal gets this 
cue through the intraorganic sensations. The rat wanders till it 
finds that it puts forth a certain amount of effort in a certain 
direction and then turns in a certain direction, ete.; this com- 
bination is familiar, so that the correct movements for the rest 
of the course are at once ‘‘set off’? by it. 

When certain passages of the maze were lengthened or short- 
ened after the animal had learned the correct path, this caused 
precisely such disturbances as would be expected if the kines- 
thetic sensations are the fundamental ones. If a passage is made 
shorter than before, the rat runs full tilt against its end, even 
though this would appear to be ‘‘in plain sight.’’ If a passage 
is made longer, the rat tries to turn when it has gone the usual 
distance; it thus runs against the side wall. If a blind passage 
now opens at a distance corresponding to that of a former correct 
turn, the rat runs into the blind passage. 

After many trials in the altered maze the rat finally learns to 
run through it as readily and correctly as before. This result 
is reached after many experiences of running into ends, ‘‘nos- 
ing’’ along side walls, trying to turn where there is no passage- 
way, and the like. The reader is inclined to see here an excel- 
lent opportunity for study of the transformation of cues from 
outer sense data into kinesthetic cues. But again the authors 
argue that the whole is purely a matter of the inner sensations. 
If they would explain clearly just how the animal gets its kines- 
thetic cues without aid from outer sense data; how it learns 
without running into the end of a passage that it must put forth 
only so much energy in a certain direction; or if they would 
demonstrate that bumping into walls, nosing along passages, 
and the like, gives no extraorganie sensations of any consequence, 


360 THE AMERICAN NATURALIST [Vou. XLII 


the reader would appreciate better their argument as to the ex- 
clusive role of the inner senses. One is slightly inclined to feel 
that the authors are making the common mistake of weakening 
the effect of a demonstration of the unsuspected great importance 
of a certain factor, by endeavoring to maintain that it is the only 
factor. 


Another factor in rat behavior is dealt with in the paper of: 


Slonaker.* Watson in his earlier work had found that young 
rats (25 to 30 days old) learn certain operations more quickly 


than do the adults, and this appeared to be due to the fact that — 
the young were more active. They tried, in a short time, all sorts | 


of movements, and were therefore likely to hit quickly upon the 
‘‘right’’ ones. Slonaker makes a careful study of the compara- 
tive amounts of activity in rats of different ages, in order to see 
how far this is correlated with the quickness of learning. A 
revolving cage was used, of such a character that the activity of 
the rats was automatically recorded. One such experiment, with 
several rats, lasted 25 days; another 57; another 60. It was 
found that, while there are great differences in individuals, both 
the very young rats and the old ones (age about a year) were 
comparatively inactive; the period of greatest activity falls in 
the age between 87 and 120 days. No close relation was evident 
between these results and those of Watson on quickness in 
learning. 

All together, the work of the Chicago laboratory has of late 
been directed with unusual precision on a well-defined single line 
of research. And hand in hand with this work on behavior have 
gone studies on the nervous system, growth and life history of the 
rat, many results of which have been published from the neuro- 
logical laboratory. Such a unified and intensive series o 
vestigations may well serve as a model of the best method rs 
making solid and permanent advance in comparative psychology. 

. JENNINGS. 
®Slonaker, J. R. The Normal Activity of the White Rat at Different 
Ages. Journ. Comp. Neurol. and Psychol., 17, 1907, pp. 342-359. 


(No. 496 was issued on May 18) 


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AMERICAN NATURALIST 


Vout. ALU June, 1908 No. 498 


THE ANCESTRY OF THE CAUDATE 
AMPHIBIA 


DR. ROY L. MOODIE 


UNIVERSITY OF KANSAS 


Tue phylogeny of the group of vertebrates commonly 
called amphibians or batrachians has been, and still is to 
some extent, among the most obscure of the problems con- 
nected with the descent of animals. So far as I am aware 
there have been but few statements as to the possible 
ancestry of the Amphibia and no attempt has been made 
to set forth in detail the series of structures through 
which the animals have passed from the beginning of 
their line to the present. During the course of an ex- 
tensive investigation on the extinct Amphibia of North 
America, the writer has reached some interesting con- 
clusions in regard to the ancestry of at least one group of 
the modern Amphibia and these conclusions are here set 
forth in detail. Some of the facts offered in support of 
these conclusions have been given in other connections. 

So far as at present known, the first trace of vertebrate 
life on earth is that of fishes in Ordovician rocks in Colo- 
rado and in two places in Wyoming, i. e., the Black Hills 
and the Big Horn Mountains. In the Devonian, if the 
impressions from the Catskill are properly interpreted, 
the fishes had given rise to a quadrupedal type of animals 
which are usually known as the Amphibia. Only impres- : 
sions of footprints in the sandstone are known, but these 
are quite instructive. There are no traces of the bones 

361 


362 THE AMERICAN NATURALIST (Vor. XLII 


Fig. 1. Restoration of Micrerpeton caudatum Moodie from the Coal Meas- 
ures of Illinois, Length of form, 49 mm. Spider is a composite restoration 
and is based on actual specimens and on the results of Roemer, Scudder, 
Beecher and Melander. x 2}. 


of these quadrupeds known in rocks of Devonian or of 
Mississippian age, although Lohest (1) some years ago 
called attention to some remains which he thought were 
amphibian from the Devonian rocks of France. Thevenin 
has recently cast doubt upon this interpretation by 
Lohest (2) and the figures as given by Lohest would seem 
not to be amphibian, but fish remains. 

In rocks of the lower part of the Pennsylvanian occur, 
in North America, the first evidences of the bones of 
quadrupeds. The Amphibia show, even thus early, that 
their line had divided into three and possibly four dis- 
tinct groups which are usually known as the Branchio- 
sauria, the Microsauria, the Aistopoda and the Stereo- 
spondyli. The presence of the last group is indicated 
by the two vertebre from the Carboniferous of Nova 
Scotia named by Professor Marsh Eosaurus canadensis 
and also by certain fragments of large ribs and large 
skulls from the coal beds of Ohio. The Temnospondyli 
‘did not make their appearance until the latter part of the 
Pennsylvanian, when their remains are found in Carbon- 
iferous rocks of Kansas, Illinois and Pennsylvania. 


No. 498] THE CAUDATE AMPHIBIA 363 


The Stereospondyli and the Temnospondyli are spe- 
cialized side branches of the amphibian or reptilian stem 
and will not concern us further here. The Aistopoda are 
regarded by the writer at present as being specialized 
microsaurians. This would not favor the view of Wie- 
dersheim as to the descent of the Cecilians. This point 
needs further investigation and will be discussed else- 
where. The Microsauria Dr. Gadow has placed in the 
subclass Proreptiliz and, in the opinion of the writer, his 
classification represents the correct facts, but further dis- 
cussion will be postponed. The group to ,which the 
reader’s attention is here invited is the one usually known 
as the Branchiosauria, representatives of which are found 
only in Western Europe and in North America, where a 
single specimen is known from Illinois. The group is a 
very small one both as to the size of the individual mem- ` 
bers and as to the number of species. 

The Branchiosauria are distinguished from all of the 
other Amphibia-like vertebrates by the presence of short, 
heavy, straight ribs. The Microsauria always have long, 
thin, curved ribs. The Aistopoda usually are destitute of 
ribs or when present they are curved and slight. In con- 
versation recently with Dr. Gadow he made the interest- 
ing suggestion that the characters presented by the ribs 
might be used as a basis on which to separate the group 
heretofore known as Stegocephala into two main di- 
visions. One of the divisions would be the true Amphi- 
bia with the Branchiosauria as the representative order 
among the early forms, in which case the term Branchi- 
osauria would be a misnomer, and the other Stegocephala 
would be included under some such name as the Pro- 


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G. 2. Outline of a Larva of Necturus, showing the arrangement of the 
lateral line systems. After Platt. 


THE AMERICAN NATURALIST [Vou. XLII 


364 


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CO ass 


The 
The broad ventral 


‘peton caudatum Moodie. 


Skeleton of Micrer 


Fic. 3. Restoration of the 
feet are conjectural and are based on the studies o 


armature is well developed in this form. 


f Credner. 


x3 


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No. 498] THE CAUDATE AMPHIBIA 365 


latter group is characterized by the long curved ribs 
borne intereentrally. There seem to be some difficulties 
in this classification, but it is hoped that they may be 
cleared up by future investigation. 

The Branchiosauria, as has been several times sug- 
gested by various authors, represent the ancestral forms 
of at least the tailed division of the Amphibia. A sug- 
gestion as to the ancestry of the tailless forms will be 
given elsewhere. The conclusion that the Branchi- 
osauria are the direct ancestral forms to the modern 
Caudata is based on several characters. These char- 
acters are: the structure of the skull, the structure and 
form of the vertebre and ribs, the number of digits, the 
arrangement of the phalangeal elements, the characters 
of the pectoral and pelvic girdles, the character of the 
lateral line system, the structure and form of the long 
bones and finally the shape of the body; all of which will 
be discussed below. 

It has been suggested on embryological grounds that 
the Amphibia are a degenerate group (3) and this is 
borne out, in so far as the Caudata are concerned, by a 
study of the cranium of the early and recent forms as 
- well as by other structures. The cranium of the Branchi- 
osauria is almost identical in structure with that of the 
Microsauria and it exhibits a completely roofed-over skull 
with only five openings, namely, those for the orbits, the 
nostrils and the pineal opening. 

The elements forming the roof of the skull are quite 
constant in the Branchiosauria and also in the Micro- 
sauria and they differ only in position and relations. 
Practically the same elements form the skull roof in the 
two groups, but the forms differ in other important re- 
spects. In the skull of the Branchiosauria we find in the 
median line a row of elements in pairs, which extend the 
entire length of the skull. These are (beginning an- 
teriorly): the premaxille, the nasals, the frontals, the 
parietals and the supraoccipitals. On the side of these 
elements lie others which vary in their position to some 
extent; the median elements are fixed and not so likely to 


366 THE AMERICAN NATURALIST  [Vor. XLII 


AEA — 
fees [ (3 

YS BA) ay WY 
AASS 


hand is conjectural and the last two on digit II and the last one on digit IV 
of the foot are conjectural. From the Upper Carboniferous of France. x2. 


vary. Anterior to the orbit there are the prefrontal, the 
lachrymal, the maxilla, and lateral to the orbit lies the 
jugal. Posterior to the orbit lie the postorbital, the post- 
frontal, the squamosal, the supratemporal, the opiotic, 
and on the postero-lateral border of the skull lie the 
quadrato-jugal and quadrate. 

In the skull of the modern Caudata we find an arrange- 
ment of the elements which is quite similar to that de- _ 
scribed for the Branchiosauria. In the skull of Megalo- 
batrachus (Fig. 10), for instance, we find the following 


Be a N 


Fie. 5. Restoration of Branchiosaurus amblystomus Cred. from the Per- 
mian of Saxony. After Credner. 


No. 498] THE CAUDATE AMPHIBIA 367 


bones paired in the median line: the premaxille, the 
nasals, the frontals, the parietals, and on the posterior 
end of the skull occur the exoccipitals. In this series it 
is clear that the supraoccipital elements have disap- 
peared. Lateral to the median paired row there are the 
maxilla, the prefrontal, the squamosal, and in allied forms 
the jugal, quadratojugal and quadrate. The epiotic is 
wanting in all skulls of modern amphibians except some 
coccidians and the elements are not so firmly united as 
in the skull of the Branchiosauria. The skull of the 
Caudata exhibits a weaker, more degenerate condition, 
than is found among the early forms. The lower sur- 
face of the skull is practically the same in the two groups, 
especially in the possession of alarge parasphenoid. Teeth 
on the palate bones are lacking, for the most part, in the 
modern forms, which is another evidence of degeneracy. 

If the structure of the vertebre is now examined it will 
be seen that in this particular there is close affinity 
between the modern Caudata and the Paleozoic Branchi- 
osauria. The vertebre of the modern Caudata are 
amphiccelous and opisthoccelous, with the notochord rarely 
persistent and with the transverse processes springing 
off boldly from the body of the centrum. Similar condi- 
tions are observed in the Branchiosauria where the ver- 
tebræ, so far as they are known, are amphiccelous and the 
transverse process is unusually strong with the notochord 
probably persistent. The transverse processes give sup- 
port to the short, heavy, stout ribs which lay in the flesh 
and made acute angles posteriorly with the vertebral 
column. The ribs in the Branechiosauria and in the later 
Caudata are indistinguishable so far as form is con- 
cerned. The point of difference is that in the modern 
forms the ribs are usually weaker posteriorly and are, 
for the most part, confined to the presacral region of the 
body. This is another instance in which the Caudata 
show their degenerate structure. On the basis of the ribs 
alone the Branchiosauria may well be separated from the 
Microsauria and from all other of the so-called Stego- 
cephala, and would be considered as the true Amphibia, 


368 THE AMERICAN NATURALIST [Vou XLII 


Fic. 6. Restoration of Melanerpeton from the Permian of Saxony. After 
Credner. 


while all other forms would be excluded from this class 
and would have to be placed among the Reptilia, where 
they probably belong; whether they are to be considered 
as a subclass of the Reptilia or not, does not concern us 
here. 

In the forelimb there are never more than four digits 
either in the Paleozoic Branchiosauria nor in the later 
Caudata. So far as I am aware, there is no paleonto- 
logical evidence to show that there ever were more than 
four digits in the hand of the caudate Amphibia and in 
this discussion the first digit will be considered as No. I., 
the second digit as No. II. and so on. Fritsch, it is true, 
has figured five digits in the hand of Branchiosaurus sala- 
mandroides Fr. (Fig. 7), from the Permian of Bohemia, 
(4) but in giving us a glimpse into the material on which 
his restoration is based there are only four digits pre- 
served in the hand, although Fritsch says the first had 
been lost. I doubt if there ever were more than four, and 
the digits in Fritsch’s specimen were all preserved. In 
all of the Permian forms from Saxony Credner has 
figured four digits in the hand (Figs. 5-6). 

The specimens recently described by Thevenin from 
the Upper Carboniferous of France (5) show only four 


No. 498] THE CAUDATE AMPHIBIA 369 


digits in the hand. In Fig. 4 a restoration of the 
Branchiosaurus fayoli Thevenin has been attempted. 
The reconstruction is based on the figures as given by 
Thevenin. Only one phalanx is restored and that is the 
distal one of the first digit. All of the rest were pre- 
served. In the Wealden of Belgium the Hyle@obatrachus 
croyii Dollo (Fig. 8) exhibits but four digits in the hand. 
In Andrias scheuchzeri Tschudi (Fig. 9) from the Mio- 
cene of Switzerland, there are but four digits in the hand, 
and in all of the modern caudate forms, so far as I am 
aware, there are but four digits and the phalangeal 
formula for all, both in Paleozoic and in later forms, is 
universally 3-3-4-3. 

In the foot the Branchiosauria show the same agree- 
ment with the modern Caudata. There are always five 
digits and they usually have the phalangeal formula 
4-5-4-3-3. Neither the carpus nor the tarsus is fully 
ossified in the Branchiosauria or in the later Caudata, 
although the carpus and tarsus are partly osseous in the 
Amblystomatide. 

The pectoral girdle of the Branchiosauria consists 
usually of four elements, three paired and one unpaired. 
These are: the single interclavicle, the clavicles, the cora- 
coids (cleithra?) and the scapule. Among the modern 


i i 
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YY x LE 
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S e = 
XL. SOLS MANA is ex 


5 LSS i 
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Fia Restoration of a salamandroides Fr, from the Per- 
mian of Se Modified after Fritse 


370 THE AMERICAN NATURALIST  [Vou. XLII 


Fic. 8. Hylwobatrachus ey, Dollo from the Wealden of Bernissart. 
After Dollo. 
caudate forms as well as among the Miocene forms all of 
the elements with the exception of the scapule have be- 
come cartilaginous, so that there remains in the modern 
caudate amphibians only a bony scapula. This seems to 
be the case in the Wealden Hyleobatrachus, but the single 
specimen is not well enough preserved to furnish definite 
information on this point. The pelvic girdle has, ap- 
parently, undergone no change in the evolution of the 
Caudata. The pubis is never ossified in either the 
Branchiosauria or in the latter Caudata and the ischium 
is usually plate-like, while the ilium is more or less 
rounded. The sacral rib, of which there is never more 
than one pair, is usually well developed. 


Fic. 9. Restoration of Andrias scheuchzeri Tschudi based on the draw- 
ings published by von Meyer in “ Fauna der Vorwelt.” x4 


No. 498] THE CAUDATE AMPHIBIA 371 


In an essay now in press on ‘‘ The Lateral Line Organs 
in Extinct Amphibia” the writer has called especial 
attention to the character of the lateral line organs as 
they are preserved in the single specimen of a branchi- 
osaurian, Micrerpeton, from the Coal Measures of Illinois. 
A restoration of this form has been attempted in Fig. 1. 
The animal, as preserved, measures only 49 millimeters. 
It is apparently an adult, as there are no evidences of 
branchie and the limb bones are well formed. The 
spider shown in the restoration is a composite and is 


EET Rtn, 


9 G 


É 
YV 


wg, 


p 
Panty. 
(Save i 


oS 


. After Osawa. 


Fig. 10. The Skeleton of Megalobatrachus japonicus 


based partly on actual specimens partly on the results 
of Roemer, Beecher, Seudder and Melander. The body of 
the spider which was used as a model was about a half an 
inch in length. The particular characters in the amphib- 
ian which deserve mention now are the two lines repre- 
senting the lateral line organs. There is seen a median 
lateral line which starts at the tip of the tail and runs 
forward. The other begins somewhat anteriorly and 
springs boldly from the median lateral line at a distance 
of a few millimeters from the tip of the tail. These lines 
represent rows of pigmented scales which show on the 


372 THE AMERICAN NATURALIST [Vou. XLII 


specimen as dark lines. The sense organs were un- 
doubtedly located beneath these specialized seales, much 
as the lateral line organs are protected in some of the 
fishes. In Necturus (Fig. 2) the arrangement of the 
lateral line organs is almost identical with what has just 
been described for Micrerpeton. I have suggested else- 
where that this similarity in the lateral line organs of 
these two forms may be indicative of relationship between 
the groups to which these forms belong. There is no 
reason why the type of lateral line should not have been 
preserved in the amphibians, since we know that in some 
of the fishes certain types of peculiar lateral line struc- 
ture have persisted for nearly as great a length of time. 

In the structure of the limb bones and ribs the Branchi- 
osauria are much like the modern Amphibia in that the 
bones are formed almost entirely of perichondrium. 
There are never any bony epiphyses in any of the Am- 
phibia. In some of the toads Parsons has seen the 
cartilagmous epiphyses calcified, but they are never 
osseous. The endochondrium is not at all or but 
slightly developed in the Amphibia, and in the fossilized 
bones this condition causes a concavity at the ends. In 
the Microsauria the endochondrium is more fully formed, 
although there are some in which the ends of the limb 
bones are nearly flat. 

The form of the body in the Branchiosauria is stri- 
kingly salamandrine, as may be seen by referring to fig- 
ures 1 and 4. In Micrerpeton the tail is quite long and 
almost equals the length of the presacral region. In the 
Branchiosaurus fayoli Thevenin (Fig. 4), the tail is 
shorter but the form is much the same. The body of the 
Branchiosaurus (Fig. 4) is more stout than that of the 
Micrerpeton (Fig. 3) and the ribs are longer. 

In summing up all of the characters as presented by 
the Caudata and the Branchiosauria it seems most prob- 
able that the Caudata are but degenerate Branchi- 
osaurians and the changes which have taken place in the 
skeleton are mostly brought about by the loss of certain 
parts. ‘ 


No. 498] THE CAUDATE AMPHIBIA 373 . 


SuMMARY 


1. The Stegocephala will probably have to be divided 
into two groups, one of which will be considered as 
Amphibia and the members of the other group will have 
to be placed among the Reptilia but can not all be placed 
under any single head since they represent divergent 
types and must be placed in with the reptilian groups to 
which they have probably given origin. 

2. The Branchiosauria are the ancestral forms of at 
least the caudate Amphibia. The Branchiosauria are 
first known in the Pennsylvanian of North America and 
they present characters which separate them clearly from 
all other groups of the so-called Stegocephala. 

3. The characters which the Branchiosauria have in 
common with the Caudata are: short, straight ribs; stout 
transverse processes springing from the body of the 
vertebra; practically the same number of presacral 
vertebrae; the same skull structure; the degenerate char- 
acter of the pectoral girdle and the close correspondence 
of the pelvie girdle; the same number of the digits and 
the same phalangeal formula in the Branchiosauria and 
Caudata; the similar characters presented by the lateral 
line system; the structure of the long bones and the shape 
of the body. 

4. There can be but little doubt that the Caudata are 
the direct descendants of the Branchiosauria, of which 
they are but degenerate forms. 


BIBLIOGRAPHY 


1888. Lohest, M. Annales de la Société Geol. de Belgique, Tome XV, 


p. @xx. 
1906. Thevenin, A. Annales de Paleontologie, Tome I, Fascicule III, p. 13. 
1907. Hatta. On Gastrulation in Petromyzon. Journ. of the College 
of Science, Tokyo. 
1889. Fritsch, Anton. Fauna der Gaskohle. Bd. I. 
1906. Thevenin, A. Annales de Paleontologie, Tome 4, Fascicule III, p. 9, 
Plate I. 


THE SPIROCHETES AND THEIR RELATION- 
SHIP TO OTHER ORGANISMS 


PROFESSOR HENRY B. WARD! 


UNIVERSITY OF NEBRASKA 


In Ehrenberg’s famous work, ‘‘ Die Infusionstierchen 
als vollkommene Organismen,’’ written in 1838, the 
fourth family of the Vibrionides, or vibrating animal- 
cules, includes five genera which that author regarded as 
animals and distinguished as follows: 


‘rectilinear (by rect- 


HOW ete ce a Bacterium 
angular transverse 


fl .. Vibri 
Segmented threads | serpentine and flexible .. Vibrio 


fission ) 
(monad-stocks) $ spirally twisted (by f twisted segments 


oblique transverse BRE cd's satires Spirocheta 

| fission ) cylindrical elongate 
` A Spirillum 

re diseoidal compressed 

Spirodiscus 


The details of structure which Ehrenberg had else- 
where worked out with too imaginative industry, he sadly 
acknowledges are here ‘‘barred to our present powers of 
vision by virtue of their minuteness’’; and he is forced 
to depend upon scanty data to differentiate the to him 
closely related genera. To-day three among the asso- 
ciated genera are generally recognized as bacteria and of 
the spirochetes alone is there doubt as to their proper 
relationship in the systematic tree. 

However, Ehrenberg was not the first to observe such 
organisms. In 1773 O. F. Miiller described corkscrew- 
like animaleules found in foul water, and in 1786 dis- 
cussed and figured several species, unconscious that in 
1777 Kohler had published the first figure of such a form. 


1 Studies from the Zoological Laboratory, The University of Nebraska, 
under the direction of Henry B. Ward. No. 90. 


374 


No. 498] THE SPIROCHETES ~ 375 


Yet both descriptions and figures are far too indefinite to 
permit of more than a guess as to the genus under con- 
sideration. Even Ehrenberg’s work affords scanty 
means for the recognition of the forms of which he listed 
one spirochete and three spirilla. The group, though 
familiar to all students of microscopie life, has remained 
only superficially known up to very recent times, in fact 
until the discovery of the important rôle which certain 
of them play in the production of disease turned once 
more the attention of investigators in this direction. De- 
spite the characteristic of flexibility noted by Ehrenberg, 
and the indifference they displayed towards ordinary 
methods of bacteriological culture, most authors have 
grouped these organisms together among the bacteria. 
Renewed attention to the group served to emphasize at 
once radical differences of opinion as to its interpreta- 
tion. 

Undoubtedly the impetus to this study was given by 
Schaudinn’s discovery of such an organism in syphilis 
and the intuitive inference which has been abundantly 
verified that others would be found in similar relation to 
diseases as yet entirely unexplained. Working on this 
and on other species, Schaudinn confirmed the view of 
Ehrenberg as to the characteristic flexibility of the 
spirochetes, and determined the occurrence of longi- 
tudinal division and the presence of polar flagella, single 
save just before division. He also demonstrated certain 
differences between the form found in syphilis and other 
common spirochetes, which he thought served to justify 
their generic separation. Throughout he maintained 
firmly the animal nature of the group. 

Almost simultaneously there appeared in 1906 several 
papers which dealt with the problem as to the nature of 
this group and arrived at diametrically opposite conclu- 
sions. In the first, by the parasitologist Blanchard 
(1906), was analyzed briefly the morphological basis for 
the genera of microorganisms in which the body has the 
form of a spiral. In comparison with these the author 


376 THE AMERICAN NATURALIST [Vou. XLII 


considered very briefly also certain clearly bacterial forms 
(Spirosoma, Vibrio, Spirobacillus) and others distinctly 
flagellate (Trypanosoma, Trypanoplasma) which in his 
opinion manifest close relationship to the true spiral 
microorganisms of which he recognized three well- 
founded genera, Spirillum, Spirocheta and Treponema. 
The group of plant organisms he classed as follows: 


SPIROBACTERIA Cohn 1875 

Bacteria more or less curved in a spiral, the curve form- 
ing at times only the are of a circle, in other cases form- 
ing spiral coils more or less numerous. Organisms little 
flexible or not at all, multiplying by transverse division. 
Formation of endogenous spores demonstrated in a num- 
ber of species. 

Four genera: Spirosoma, Vibrio, Spirobacillus, Spiril- 
lum. 

Of the last genus he says: Spirillum Ehrenberg 1830— 
Body spiral, cylindrical in transsection, not tapering at 
the ends. No undulating membrane. One or several 
flagella bent in a regular curve, either at both extremities 
or at one only. Formation of endogenous spores demon- 
strated in a number of species. Organisms relatively of 
considerable size, cultivated easily on various media used 
in bacteriology. 

The spirilla are clearly bacteria. They live as sapro- 
phytes in wells, stagnant waters, the soil, liquid manure, 
ete., and generally in media very poorly oxygenated. 
Possibly one should include in this genus some forms 
which are found in pus, but it is doubtful if these play an 
active part in it, and up to the present time not a single 
species can be considered as surely pathogenic. 

Over against these forms, and sharply contrasted with 
them Blanchard placed the animal organisms of a general 
spiral form. These he included in a single family, char- 
acterized thus: 


No. 498] THE SPIROCHETES 377 


Trypanosomip2 Doflein 1901 

Flagellates twisted into a spiral, the coils being more 
or less numerous. Organisms flexible, with form more or 
less fixed, multiplying by longitudinal division. No 
endogenous spores. Locomotive apparatus consisting 
either simply of an undulating membrane, or of such a 
membrane together with one or two flagella. Not stained 
by Gram’s method, not cultivated in the media used in 
bacteriology. 

Four genera: Spirocheta, Treponema, Trypanosoma, 
Trypanoplasma. 

The first two genera are very similar and include the 
only forms concerning the animal nature of which there 
is any question. It will be necessary to consider these 
somewhat closely. The first is characterized thus: 


SprrocH#ta! Ehrenberg 1833 

Body excessively slender, spiral, flattened, ectoplasm 
extending in a narrow undulating membrane which sur- 
rounds in a spiral the entire body. No flagella, no 
endogenous spores. Nucleus greatly elongated, filiform, 
in the axis of the body, with chromatin granules dis- 
tributed along its surface. Reproduction in all proba- 
bility by longitudinal division. None of the media used 
in bacteriology serve to maintain cultures of these organ- 
isms. Type species, S. plicatilis. 

All these forms are by some students assigned to the 
bacteria. Some species are inhabitants of stagnant 
waters, others live in the sea or in decaying organic 
materials, while still others are parasitic. Among the 
latter are forms recently recognized as the cause of most 
virulent infective diseases in man and other animals. 
The genus characters given above are not in their original 
form, but as emended by Blanchard, and this emendation 
becomes now the basis of the group thus named. The 
emendation is based primarily upon the epoch-making 
investigations of Schaudinn. 

1 The name is often written Spirochete, which does not conform to rules 
of Latin or of nomenclature. 


378 THE AMERICAN NATURALIST  [Vou. XLII 


Blanchard lists in this genus the following species: 

1. S. plicatilis Ehrenberg 1833, from stagnant water. 

2. ©. buccalis Cohn 1875, from the buccal cavity. 

3. S. obermeiert Cohn 1875, from the blood of man in 
cases of relapsing fever. The possible varieties of this 
species, found in various types of relapsing fever, are 
also noted. 

4. S. dentium Koch 1877, very small species from the 
mouth. 

5. S. gigantea Warming 1875, from brackish water. 

6. S. eberthi (Kent 1880), from the intestine of birds. 

7. S. balbianu (Certes 1882), from the intestine of 
lamellibranchs. 

8. S. anserina Sakharov 1891, cause of septicemia in 
birds. 

9. S. theileri (Laveran 1903), from blood of cattle. 

10. S. pyogenes (Mezincescu 1904), from pus in a case. 
of pyelitis. 

11. S. gallinarum R. Blanchard 1905, cause of septi- 
cemia among chickens. 

12. S. refringens Schaudinn 1905, from lesions of 
syphilis. : 

13. S. pertenuis Castellani 1905, from lesions of yaws. 

14. S. ovina R. Blanchard 1906, from blood of sheep. 

15. S. vincenti R. Blanchard 1906, from abscesses in 
man. 

Also several other uncertain forms. 

It is evident that this assemblage of forms is not 
entirely natural. Of many little is known beyond the 
size and manner of life. The latter presents radical dif- 
ferences, but the formation of new genera on purely physi- 
ological grounds is recognized as a most dangerous pro- 
cedure. No doubt better knowledge, especially of the life 
cycles, will lead to the removal of groups of these species 
to new genera, but such must be based upon distinctive 
characteristics; any other method only results in greater 
confusion. New forms are being described constantly, 
e. g., S. lymphatica, which White and Proescher regard 


No. 498] THE SPIROCHETES 379 


as the cause of a lymphatic spirillosis; it stains like 
Treponema pallidum. More extended investigation 
alone will justify assigning a definite place to such organ- 
isms. Yet apparently the group of spirochetes produ- 
cing relapsing fevers may justly be made an independent 
genus, even though their morphological differentiation is 
difficult. They constitute the newly created genus. 


SPIROSCHAUDINNIA Sambon 1907 

' Blood parasites only imperfectly known. In blood .of 
vertebrate host, they appear as minute, wavy or spiral 
threadlike bodies. With undulating membrane but no 
flagella. Free stage alternates with intracellular resting 
stage with parasite coiled up in host cell. Sporogony in 
ticks. Stages have been demonstrated in ova, showing 
the hereditary transmission of the infection. This is con- 
trary to known facts regarding bacteria. Type species, 
Spiroschaudinnia recurrentis. 

This genus is as yet not clearly differentiated from 
Spirocheta and may ultimately prove to be synonymous 
with it. The presence of an intracellular stage and the 
mode of infection through biting insects are the slender 
basis on which it rests at present. 

In this genus Sambon has included two forms which 
produce relapsing fevers in man. One is S. recurrentis 
(Lebert 1874), better known by the synonym Spirillum 
obermeieri Cohn 1875, which is the cause of the relapsing 
fever common in Russia, the Balkan Peninsula, Turkey, 
Persia and India, and known by sporadic cases over the 
entire world. Patton has shown that the parasite is 
transmitted by the common bedbug (Acanthia lectularia) 
and possibly by the body louse (Pediculus vestimenti), 
although the evidence is not conclusive. The second 
species, S. duttoni, the cause of African relapsing fever, 
is difficult to distinguish morphologically from the fore- 
going, but is shown by experiment in animals to be dis- 
tinet from it. According to Dutton and Todd the organ- 
ism is transmitted by the tick, Ornithodoros moubata 


380 THE AMERICAN NATURALIST [Von XLII 


(Murray). The young of infected ticks are capable of 
inoculating the disease and the spirochetes have been 
found in the eggs, where in fact they multiply and thus 
infect the new-generation. This is evidently true heredi- 
tary transmission of disease. 

A third species should be added to this genus, namely, 
the organism producing the relapsing fever of Bombay 
which Novy and Mackie have shown by inoculation ex- 
periments to be distinct from either of the preceding 
forms. To this form the name Spiroschaudinnia carteri 
has recently been given by Mackie. The disease caused 
by this species has been transmitted experimentally by a 
grooved needle and also by the bedbug, and none of. the 
experimental animals contracted the disease in any other 
way than by inoculation. 

In his outline Blanchard included one other genus, 
which with its diagnosis is as follows: | 


TREPONEMA Schaudinn 1905 

Spiral body not flattened, but cylindrical in trans- 
section, tapering towards the extremities. One flagellum 
at each extremity, no undulating membrane. Multiplica- 
tion by longitudinal division, the initial stage of which 
may be identified by the doubling of the flagellum at one 
of the ends. Division forms remain long attached by 
their ends. ‘Type species; T. pallida. One of the 
marked characteristics of this spirochete is the resistance 
to ordinary methods of staining. This stands in sharp 
contrast to conditions among bacteria. Gram’s method 
and many others do not stain it at all, while no stain 
colors it deeply. 

This form was discovered by Schaudinn and Hoffmann 
in syphilitic lesions; it has been experimentally trans- 
ferred to apes, with the result of producing characteristic 
signs of the disease and has not been found in other 
diseases. Another species, T. pertenwis (Castellani 
1905), which is regularly associated with the tropical dis- 
ease known as frambeesia, or yaws, also belongs here. 


No. 498] THE SPIROCHETES 381 


But even after these forms have been removed 
Blanchard’s original list of the genus Spirocheta still 
shows an unnatural mixture of varied forms. Among 
the remaining species are undoubtedly those which form 
other natural groups and will later be assigned to new 
genera; but in the absence of fuller knowledge they may 
preferably be left for the present in the old genus. No 
doubt new forms will be added to this list. In this con- 
nection attention should be called to yellow fever and the 
view often expressed that the yet unknown cause of this 
disease will also prove to be a spirochete. Similarly the 
Miana disease of Persia known to be transmitted by a 
bird tick, Argas persicus, and other tick diseases in 
tropical and subtropical countries are thought to be due 
to the inoculation of closely related organisms. 

Only two weeks later than the publication by Blanchard 
appeared an extensive paper by Novy and Knapp (1906). 
These authors recorded studies on a spirochete from a 
case of relapsing fever which was observed in Bellevue 
Hospital, New York. They regarded this form as iden- 
tical with S. recurrentis and as the result of most careful 
studies reached the conclusion that the organism in ques- 
tion was undoubtedly a bacterium and not a protozoon. 
Their figures show strong evidence of transverse division 
and fail to indicate any trace of bodies which might be 
interpreted as nucleus, blepharoplast, or undulating mem- 
brane. They indicate also the presence of a single 
flagellum at one end of the spiral about as long as the 
spiral itself and with wavy turns corresponding in gen- 
eral to those of the spirochete, while a short process occurs 
at the other end. The staining qualities of the flagellum, 
the action of the organism under the influence of 
plasmolytic changes, its behavior both during and after 
being killed by heat and also the persistence of the spiral 
form under the most varied injurious conditions, are in- 
compatible, in their opinion, with.a protozoan nature and 
indicate affinity to the bacteria. The readiness with 
which these authors established active immunity is of- 


382 THE AMERICAN NATURALIST [Von. XLII 


fered as additional proof of the bacterial nature of the 
form with which they experimented, and finally they 
record,the absence of a tendency to form layers around 
each air bubble, which is a very characteristic reaction 
for trypanosomes. Novy and Knapp conclude thus: 

“ The several facts which have been brought out under the preceding 
headings point clearly to the non protozoal nature of S. obermeieri. 
We must conclude, therefore, that the S. obermeieri belongs to the. 
bacteria and more especially to the Spirillacee. As pointed out, the 
same conclusion has been reached by Borrel as regards S. gallinarum 
and S. duttoni. Three typical spirochetes are therefore demonstrated 
to belong to the group of bacteria. 

“ Hitherto it has been assumed that insect transmission indicates a 
protozoal organism, and in so far as the spirochetes are concerned, 
the chief evidence which can now be adduced in support of their 
animal nature is the fact of such transmission in the case of S. duttoni 
and S. gallinarum. The facts brought out in this study point so con- 
clusively to the bacterial nature of the organisnfs that there can be 
little or no doubt of the correctness of the conclusion arrived at. 
With the recognition of this proof it follows that insect transmission 
is no longer a criterion of the nature of an organism.’ 

Radical as is this critique of the animal theory of 
spirochete relationship, it has not been aecepted as deci- 
ding the question, and has only provoked further discus- 
sion of the problem. Referring first to the question of 
insect transmission, it may be said that Koch has shown 
that the spirochetes multiply in the eggs of ticks and 
Carter that they undergo there changes as yet unex- 
plained which may substantiate the claim of another 
eycle. Several investigators have found that in experi- 
mental animals they pass through the placenta from the 
maternal circulation to the fetal, although they undergo 
no changes consequent to this transfer. These observa- 
tions do not aes with known facts concerning other 
bacteria. 

Almost at the same time there was published an ex- 
ceedingly careful investigation into the structure and de- 
velopment of the fowl spirochetes by Prowazek, with an 
appendix on a species from -Anodon by Keysselitz, in 
which both authors come to conclusions diametrically op- 


No. 498] THE SPIROCHETES 383 


posed to those of Novy and Knapp with regard to the 
structure and relations of the spirochetes. It should be 
remembered that the species (S. gallinarum) on which 
Prowazek worked was one of those which Novy regarded 
as most positively of plant affinities. On the basis of 
most critical observations Prowazek indicates the pres- 
ence of an undulating membrane with a conspicuous 
marginal cord. The body of this spirochete he finds to be 
flexible, a feature emphasized by various authors in the 
diagnosis of the genus. An analysis of the various types 
of movement shows, in his opinion, marked similarity to 
organisms possessing an undulating membrane or to the 
similarly provided sperm cells. Distinct granules lie in 
the axis of the organism which do not constitute a definite 
nucleus in the general sense of the term, but form 
chromidia such as are well known to occur frequently in 
the protozoon cell in the place of a single cireumscribed 
nucleus. 

So far as the conduct of these spirochetes towards 
reagents is concerned, the use of salt solutions did not 
produce the plasmolysis characteristic for bacteria even 
though the solutions were stronger than those sometimes 
successful in effecting this among the bacteria. Dilute 
alkaline solutions affected the spirochetes whereas the 
bacteria are very resistant towards them. 

The identification and interpretation of the method of 
division is believed to be of especial importance in de- 
termining the systematic position of the spirochetes. In 
the opinion of Prowazek transverse division may oceur, 
yet positive evidence demonstrated the occurrence of 
longitudinal division. Similar conditions in part were 
found on the species from the mouth (S. dentium), and 
were especially clearly illustrated by the observations of 
Keysselitz on a spirochete obtained from the fresh water 
mussel. Here the character of the undulating membrane 
and of the chromidia, the conduct of the chromatin 
granules in advance of division and the essential features 
of that process which was clearly longitudinal could be 


384 THE AMERICAN NATURALIST [Vou. XLII 


most distinctly observed and delineated. Finally 
Prowazek calls attention to various protoplasmic accumu- 
lations or globules which make their appearance at cer- 
tain times and in his opinion are not mere products of 
regeneration, but represent special resting stages in which 
protoplasm and chromatin granules experience involu- 
tion. These peculiar processes have also been observed 
by other investigators on other species and may possibly 
be interpreted as particularly related to the sexual cycle. 

Prowazek concludes that as regards the systematic 
position of the chicken spirochete (S. gallinarum), one is 
compelled on the basis of the structure, relation to re- 
agents, manner of plasmolysis, and also on the basis of 
temporary cell parasitism to place the species among the 
protozoa and in close proximity to the trypanosomes. 
The undulating membrane was observed by Schaudinn in 
S. dentium, refringens and ziemanni. The existence of 
this structure can no longer be questioned. The large 
form discovered by Keysselitz suggests the large S. 
plicatilis and forms the transition to S. balbianw of the 
oyster which is without doubt closely related to the 
trypanosomes. 

In a very recent paper Fantham (1908) demonstrates 
the occurrence and character of the spiral membrane in 
S. balbianii and S. anodonte. He also explains the 
character of the movement as due to myonemes in the 
spiral membrane. Longitudinal division he finds to be 
frequent and to involve first the basal granules, then the 
membrane, next the chromatin masses and finally the 
body, the halves of which subsequently remain attached 
end to end. Fantham sees no clear evidence of sexual 
dimorphism, and finds the spirochetes non-plasmolyzable 
and without aerobic reactions. As characters manifest- 
ing bacterial affinities he lists the diffuse nucleus like 
spirilla; transverse fission even though infrequent, and 
the absence of a blepharoplast. Features suggesting 
protozoan affinities are the possession of a membrane, 
longitudinal fission, their non-plasmolyzable character 


No. 498] THE SPIROCHETES 385 


and several minor or doubtful factors. The spirochetes 
he believes to be distinct from trypanosomes in their less 
highly specialized structure, which exhibits morphological 
resemblance to bacteria. 

In the face of such conflicting testimony on these 
morphological and physiological factors of primary im- 
portance for the interpretation of the group, one is com- 
pelled to seek collateral evidence to see if any can be 
secured which is definite, even though not in itself deci- 
sive. A few such indications are to be found among the 
uncontroverted records of various investigators. It is 
noteworthy that spirochetes resist culture in the media 
which serve readily for bacteria in general, and herein 
also resemble other protozoan saprozoites.? 

Among indirect evidence one should note the work of 
Marchoux.* It has been observed that spirochetes easily 
lose their virulence. This author found that S. gal- 
linarum, if passed through a series of birds, loses its 
lethal power and infectivity. In nature, however, the 
disease maintains its virulence, destroying entire broods 
in countries where it is endemic. The persistent viru- 
lence is thus seen to be related to the transmitting agent, 
the tick Argas miniatus. However, these ticks are in- 
capable of increasing the virulence of a strain that has 
become attenuated and merely maintain any strain at its 
own level. These conditions do not resemble the action 
of bacteria, but, on the other hand, do simulate the con- 
duct of protozoa, which pass through part of the life cycle 
in an intermediate host. 

Another indication of much importance was furnished 
by Lingard in 1903 when he observed spirochetes in cattle 
penetrating red blood cells. Prowazek describes and 
figures in detail this occurrence in the fowl’s blood where 
the parasite, after entering the corpuscle assumes a coiled 
or resting condition which he believes related in some 
manner to the (supposed) developmental cycle in the 

? This convenient term introduced by Blanchard indicates at sight its 
meaning through analogy with the well-known botanical term, saprophyte. 

"C. R. Soe. Biol., 62, October 12, 1907. 


386 THE AMERICAN NATURALIST (Von XLII 


intermediate host (Argas). Very recently Balfour 
(1907) has seen the spirochete actually enter the red 
corpuscle, and undergo changes within it in which the 
chromatin core is broken up into separate globules. This 
stage is very difficult to stain and has hitherto escaped 
emphasis. Some observers believe it to represent degen- 
eration changes; even then it is incompatible with the 
theory of bacterial relationship, while, on the other hand, 
it suggests strongly conditions which prevail among other 
hematozoa. One is forced to note its great resemblance 
to the ‘‘latent body’’ of trypanosomes recently described 
by Moore and Breinl. This consists of a nucleated frag- 
ment of protoplasm which is stored up in spleen and 
bone marrow of infected animals and ultimately reap- 
pears in the circulation when it gives rise to a new 
trypanosome. 

Jaffé (1907) has studied a form (S. culicis) found in 
mosquito larve and gives a careful analysis of the motile 
phases which stand in sharp contrast with the stiff serew 
movements of spirilla. He emphasizes also the ribbon- 
shaped body, the great susceptibility to solution of KOH 
even though very dilute, the axial nuclear (?) thread, and 
the occurrence of both transverse and longitudinal divi- 
sion. 

The last work by Dutton and Todd (1907) demon- 
strated for S. duttoni a ribbon-shaped body with a cen- 
tral deeply staining core and a lighter periplastic sheath 
which at one end at least is prolonged into a flagellum. 
The central core does not stain uniformly, but has un- 
stained areas and is sometimes broken up into granules. 
While these organisms occur singly, chains of three or 
four are frequent. They usually multiply by transverse 
fission, but longitudinal division also oceurs periodically. 
Many forms taken from spleen and bone marrow are 
tightly coiled and a few of these undergo remarkable 
changes there. In the tick involution changes were ob- 
served including fragmentation of the chromatin. This 
process takes place in the Malpighian tubules where ap- 


No. 498] THE SPIROCHETES 387 


parently, the bodies burst and the granules become free to 
form the starting point for a new generation. 

The group is evidently a doubtful one even yet. The 
occurrence of chains and of transverse division strongly 
favors a bacterial interpretation, but on the whole the 
trend of recent investigation has been to indicate its 
protozoan affinities and away from the earlier view of 
bacterial relationship. The spirochetes are certainly 
distinct from the spirilla and whether they are ultimately 
placed among bacteria or protozoa, it seems clear that 
they will occupy a more isolated position than has previ- 
ously been assigned them by the advocates of either view. 
On the other hand, the recent proposal of Fantham to 
create for them a new group, the Spirochetacea, midway 
between the protozoa and the bacteria; can not be re- 
garded as a helpful move. Such proposals in other 
groups have been found on later study to be evidence of 
an insufficient knowledge of the forms under considera- 
tion. Further investigation into the life history will un- 
doubtedly furnish the definite evidence for a decision of 
the question. 

WORKS CITED 

1908. Balfour, A. Spirochetosis of Sudanese Fowls—An ‘‘ After-phase.’’ 
Jour. Trop. Med., 11, p. 37. 

1906. Blanchard, R. papire PRESA et paas micro-organisms & 
corps spirale. Arch, de Parasitol., 10, pp. 129-1 

1907. Dutton, J. E., and Todd, d; bo A Seka on pi Morphology of 
Spirocheta Duttoni. Lancet, 2, pp. 1523-1525. (Nov. 30. 

1908. Fantham, H. B. Spirochete (Trypanosoma) balbianii (Certes) 
and Spirocheta anodonte (Keysselitz): their Movements, Struc- 
ture and Affinities. Quar: Jour. Mier. Sei., 52, pp. 1-74; 3 pls., 
11 text figures. 

1907. Jaffé, J. Spirocheta culicis nov. spec. Arch. fiir Protistenkunde, 
9, pp. 100-107; 1 pl, 2 text figures. 

1906. Novy, F. G., and Knapp, R. E. Studies on Spirillum ae 
and Related Organisms. Jour. Infect. Dis., 3, pp. 391-598, 
7 pls 


pls. 

1906. Prowazek, S. v. Morpnologische und entwicklungsgeschichtliche 
Untersuchungen über Hiihnerspirochaeten. Arb. kais. Gesund- 
heitsamte, 23, pp. 554-569; 2 Taf. 


THE FAUNAL AFFINITIES OF THE PRAIRIE 
REGION OF CENTRAL NORTH 
AMERICA 


DR. ALEXANDER G. RUTHVEN 


University MUSEUM, UNIVERSITY or MICHIGAN 


Tose who are acquainted with the literature of the 
field zoology of North America are familiar with the 
fact, that, from the time of the Pacific Railroad surveys, 
naturalists have noted that there are in North America 
several well-defined biological regions. These have been 
pointed out at various times by Allen, Cope, Merriam 
and others, and the fauna of each has been more or less 
investigated. Of late years there has been a tendency 
among biologists to discredit this kind of work, owing to 
the apparent tendency of some naturalists to consider 
the mapping of these regions as an end in itself, but it 
seems to me that this work, if done properly, has a very 
real value. 

If it is true that the formation of species among verte- 
brates is orthogenetic, as Whitman (1907) holds for 
pigeons, and I have found to be true in the garter-snakes 
(Ruthven, 1908), and these species are associated with 
different sets of environmental conditions, as seems to 
be the case, for example, in the genera Leptinotarsa 
(Tower, 1906) and Thamnophis (Ruthven, 1908), it is 
manifestly of importance that these areas of character- 
ization be determined. Certain it is that the areas of 
characterization will not be the same for all animals, for 
the reaction of any form to any set of environmental 
conditions depends fundamentally upon the constitution 
of the animal, and this is a variable. On the other hand, 
in the ease of terrestrial vertebrates, there would seem 
to be enough similarity in their mode of life to render 

388 _. 


389 


FAUNAL AFFINITIES 


FESS Deciduous Forests 


TH. 
FETE Coniferous Forests 


ENT. 


(From Transeau, after Sargent.) 


For example, we have 


1es. 


No. 498] 


Sota 


+ ES 
x a NS 
* 
a ae Balt 
eS > 
a Pe 
ie 
ake RETA wees Tales prs 


x EEES 
E E a ETIN pan 
x x 
“SSeS Uae 


ty oe y fe 
x Ayes vl 

Put 
aie 

Ya 

4 

> 

x 

x 

+ 

N 

Z 

* 


x 


North America. 


them subject to the same general conditions; a fact that is 
forms of birds, reptiles and mammals characteristic of 
the plains region, others characteristic of the south- 


borne out by faunal stud 


Map showing the location of the plains, prairie, and eastern forest regions of 


390 THE AMERICAN NATURALIST [Vou. XLII 


eastern deciduous forest region, and still others char- 
acteristic of the northeastern coniferous forest region, 
ete. For these reasons it seems to me that careful faunal 
studies must contribute very materially to our knowledge 
of the affinities and relationships of forms. 

Among the biotic regions that have been recognized in 
North America, the prairie region is one of the most 
interesting. It consists in general of a narrow zone 
separating the eastern forest from the semi-arid plains, 
as shown on the accompanying map. In Iowa, Illinois, 
northern Missouri, and southern Minnesota and Wiscon- 
sin, it widens into a wedge that extends to the western 
boundary of Indiana. Pound and Clements (1900), 
Transeau (1905), Bray (1901) and Sargent (1884) have 
shown that both the environmental conditions and the 
flora of this region are characteristic, but so far as I know 
the vertebrate life has never, as a whole, received exami- 
nation. — 

During the past summer, the writer conducted an ex- 
pedition! for the University Museum, University of 
Michigan, to northwestern Iowa, for the purpose of in- 
vestigating the fauna of that region. The collections 
obtained by this expedition furnished a very representa- 
tive series of the vertebrates of the prairie region, and a 
careful study of the data seems to lead to three funda- 
mental conclusions. 

1. The peculiar environmental conditions of the prairie 
region have an effect upon the vertebrate fauna. This 
is shown by the fact that many groups become modified 
as they enter this region from the adjoining ones. Note 
the following examples: } 

(a) I have elsewhere shown that as the snake 
Thamnophis radix (B. & G.) enters the prairie region 
from the plains it becomes strikingly dwarfed. 

(b) Again, many of the plains forms are replaced in 
the prairie region by nearly related forms whose prin- 
cipal range is to the eastward of the prairie, as shown by 
the following instances: ‘ 

* Detailed reports will appear upon the results of this trip. 


No. 498] 


PLAINS 

Western yellow-thoat, Si ite 
trichas occidentalis Brew 

Pallid horned lark, Discorts: ise 
tris leucolaema (Coues). 

Western grasshopper sparrow, Co- 
turniculus savannarum bimacu- 
latus (Swains.). 

Sennett nighthawk, Chordeiles vir- 
ginianus sennetti (Coues). 

Pocket gopher, Geomys lutescens 
Merriam. 


FAUNAL AFFINITIES 


391 


PRAIRIE 
Northern yellow-thoat Geothlypsis 
trichas brachidactyla (Swains.). 
irie horned lark, Otocoris al- 
pestris practicola Hensh. 
Grasshopper 
culus savannarum passerinus 


Nighthawk, Chordeiles virginianus 
(Gmel.). 

Pocket gopher, Geomys bursarius 
(Shaw) 


(c) Furthermore many of the forms from the eastern 
forest region are here replaced by others whose principal 


range`is to the westward of the prairie. 


examples may be note 


EASTERN FOREST 
Garter-snake, Thamnophis sirtalis 


(L.). : 
Blue-tailed skink, Eumeces fasci- 
atus (L.). 
Long-billed marsh wren, Telma- 
todytes palustris (Wils.). 
Chickadee, Parus atricapillus Linn. 


Meadow lark, Sturnella magna 
(Linn.). 

House wren, Troglodytes aédon 
Viell. 


The following 


PRAIRIE 

Red-sided garter-snake, Thamnop- 
his sirtalis parietalis (Say). 

Northern blue-tailed skink, Eu- 
meces septentrionalis (Baird). 
airie marsh wren, T'elmatodytes 
palustris iliacus Ri 

Long-tailed chickadee, Pom atri- 
capillus septentrionalis ( Harris). 

Western meadow lark, Sturnella 
magna neglecta (Aud.). 

Western house wren, Troglodytes 
aëdon parkmani (Aud.). 


2. Most of the forms which inhabit the prairie region 
either extend also into the eastern forest region or into 
the plains region, or rarely both, few? being confined to 

*It is uncertain just which one of the Hog-nosed Snakes (Heterodon) 
is to be considered characteristic of the prairie region. H. platyrhinus Latr. 
has been recorded from the prairie region, and even from the plains, but 

und H. nasicus B. G. in western Iowa 
The question can only be settled by de- 
tailed collecting and by the careful determination of the specimens. 
? The pocket gopher, sonal bursarius (Shaw), and the prairie hen, 
Tympanuchus americanus (Reich.), are exceptions to this rule, both bein 
principally confined to the prairie region. 


392 THE AMERICAN NATURALIST [Vou. XLII 


the prairie region. This composite nature of the prairie 
fauna may be seen by comparing the two lists above. 

3. There is a great difference in the extent to which the 
forms of eastern North America push westward, or the 
plains forms push eastward, into the prairie region before 
becoming modified or checked. Among the plains forms 
the Arkansas kingbird (Tyrannus verticalis Say) and 
the western hog-nosed snake (Heterodon nasicus B. & G.) 
only extend into the western part of Iowa, Palo Alto 
County, being apparently the most eastern authentic 
locality recorded, but the yellow-headed blackbird, Xan- 
thocephalus xanthocephalus (Bonap.), and red-sided gar- 
ter-snake, Thamnophis sirtalis parietalis (Say), extend 
into Illinois. Again, the prairie hare (Lepus campestris 
Bach.) and others only enter the western part of Iowa, 
while the Franklin spermophile, Citellus franklini 
(Sabine), penetrates eastward as far as Illinois, and the 
thirteen-lined spermophile, Citellus tridecemlineatus 
(Mitch.), extends to southeastern Michigan.” 

Among the eastern forest forms, the Michigan mouse, 
Peromyscus michiganensis (Aud. & Bach.), cotton-tail, 
Sylvilagus floridanus mearnsi Allen, green snake, 
Liopeltis vernalis (De Kay), bluebird, Sialia sialis 
(Linn.), Baltimore oriole, Icterus galbula (Linn.), 
orchard oriole, Icterus spurius (Linn.), bob-white, 
Colinus virginianus (Linn.), swamp sparrow, Melospiza 
georgiana (Latr.), and others extend westward at least 
as far as the western margin of the prairie, while the 
Butler garter-snake, Thamnophis butleri (Cope), garter- 
snake, Thamnophis sirtalis (L.), meadow lark, Sturnella 
magna (L.), long-billed marsh wren, Telmatodytes 
palustris ( Wils.) and many other forms, only enter its 
eastern border. 

* The University expedition found the Arkansas Kingbird in Palo Alto 
County, and Heterodon nasicus on the line between Clay and Palo Alto 
Counties. 

* Mr. P. A. Traverner has recently presented to the University Museum 
a specimen of Citellus tridecemlineatus (Mitch.) from Port Huron, Mich- 


igan, and Mr. N. A. Wood, of the University Museum, has observed a 
specimen in Oscoda County. 


No. 498] FAUNAL AFFINITIES 393 


These facts, it seems to me, point strongly to the con- 
clusion, that, as far as terrestrial vertebrates are con- 
cerned, the intermediate character of the environmental 
conditions makes of the prairie region an extensive area 
of transition between the plains and eastern forest 
regions, but that the environmental conditions are not 
either intensive or extensive enough to mold the forms 
into a peculiar fauna. 


REFERENCES. 


1901. Bray, W. L. The Ecological Relations of the Vegetation of Western 
Texas. Bot. Gaz., XXXII, 99-123, 195-217, 262-291. 

1900. Pound and Clements. The Ph rtogeograph y of Nebraska, Lincoln. 

1908. Ruthven, A. G. Variations and Gen Bi eaters of the Garter- 
snakes. Bull. U. S. Nat. Mus., x (In ss.) 

1906. Tower, W. L. An Investigation of Bvotution i in Chrysometia Beetles 
of the Genus Leptinotarsa. Carnegie Inst., Pub. No. 

1905 Transeau, E. N. Forest Centers of Eastern Aah se NAT., 


XIX, 875-889. 
1884. Sargent, C. S. Forests of North America. 10th Census ot the 
U. Vo IX 


1907. Whitman, C. O. The Origin of Species. Bull. Wise. Nat. Hist. Soc., 
V, 4. 


PHYSIOLOGY? 


PROFESSOR FREDERIC S. LEE 


COLUMBIA UNIVERSITY, New York CITY 


In the introductory lecture of the present course we 
were told that ours is the golden age of mathematics. 
As week after week has passed by since then, we have 
been led from one golden age to another, convinced, for 
the time, that the present brilliant achievements of each 
science outshine those of all the others. A few days ago 
I found on my desk an entomological monograph, the 
opening sentence of which reads, ‘‘The present age is 
the age of insects.’’ I shall not attempt to harmonize the 
declarations of my Columbia colleagues with that of my 
entomological friend. But I feel that I should be derelict 
in my devotion to my own subject if I did not state 
frankly at the outset of my lecture—what ought, how- 
ever, to be a self-evident truth—that the present is pre- 
eminently the age of physiology. Nor, following again 
the example of my predecessors, need I be over-modest 
in my claims as to the place of physiology in the scientific 
hierarchy. For Fick speaks of it as ‘‘the highest and 
most fruitful generalization of the collective natural 
sciences,’’ and Czermak calls it ‘‘the summit of all the 
sciences.” 

It need not be emphasized that no exact boundary line 
exists for any one of the biological sciences. The proper 
domain of each extends, at its borders, imperceptibly into 
the domains of all, and within the boundary zones it is 
difficult to say what belongs to one and what to another. 
With this in mind it is impossible sharply to delimit the 
science of physiology. Nevertheless its proper domain is 

1A lecture delivered at Columbia University in the series on Science, 
Philosophy and Art. 

394 


No. 498] PHYSIOLOGY 395 


easily surveyed. Physiology deals with the process of 
life, the living of living substance. It is a dynamic, not 
a static science. The form, structure and composition 
of living things do not properly come within its scope: 
they form the subject matter of morphological, static sci- 
ences: But the changes in form, structure and composi- 
tion, which are manifestations of the life process, are 
proper subjects of physiological study. Its material 
exists wherever life exists. Whether it be the growth 
of a man or of a tree, the creeping of an ameceba or the 
contraction of a muscle, the beating of a heart or the 
production of a disease by a bacterium, the mental ac- 
tivity of a brain or the response of an infusorian to light, 
the process of reproduction or of inheritance, the phe- 
nomena of nutrition or the behavior of an organism to 
changes in its environment—all of these and a thousand 
others are physiological phenomena and proper subjects 
of investigation in the physiological laboratory. It is 
true that many departments of learning, which essentially 
are branches of physiological science, have been so far 
specialized in the methods of their pursuit and their aims 
and augmented by non-physiological additions, as to 
entitle them to specific names. In such cases it often is 
not expedient for physiology to busy itself with the more 
remote results of the operations of its laws. The great 
biologist of the last century, Johannes Miller, was wont 
to say, ‘‘Psychologus nemo nisi physiologus.’’ But, 
although psychic phenomena are inextricably linked with 
neural processes, the right of psychology to be recog- 
nized as an entity, with the study of psychic phenomena 
as its prerogative, has been abundantly demonstrated by 
its achievements. So, too, the proceedings of human 
society are the resultants of the action in human beings 
of physiological principles. But the study of the result- 
ants themselves falls within the special province of the 
sociologist. It is thus customary to recognize as largely 
independent sciences, such branches of knowledge as psy- 
chology, sociology, neurology, biological chemistry, exper- 


396 THE AMERICAN NATURALIST [Vou. XLII 


imental zoology, hygiene, bacteriology, pathology and 
preventive medicine; but in all these there is a large 
element of pure physiology, and their adherents often 
deserve the name of physiologists. When I say that the 
present is preeminently the age of physiology I mean it 
seriously, since at no time has the physiological spirit, 
the spirit of examining vital phenomena by the aid of 
experimentation, so completely permeated and vitalized 
the biological sciences as now. 

There exist many misconceptions regarding the subject 
matter and scope of physiology. In the popular mind 
physiology deals with the life processes of the human 
body. In reality human physiology is but one of its 
many interests. It has its anthropocentric aspect. Bio- 
centric it is in reality. The popular conception of phys- 
iology as a science of the functions of gross anatomical 
organs expresses, too, but a small part of the truth. 
During the middle part of the last century a powerful 
school of investigators in Germany busied themselves 
largely with the functions of organs, and strongly im- 
pressed the science of their time and the popular mind. 
But one of the pronounced phases of physiological de- 
velopment in recent years has been a similar rich growth 
of the study of the life processes of the cell. Another 
popular misconception is that physiology deals only with 
the internal parts of organisms—a view that is confuted 
by the fact that there is now going on much investigation 
of the mutual relations of organisms and their environ- 
ment, in other words, an expansion of what has been 
called external physiology, which might bear the newer 
title of ecology. But the wide-spread ignorance regard- 
ing the broad scope of physiology is in part explained 
by the fact that a large number of professed physi- 
ologists do busy themselves with, and most academic 
courses deal largely with, the vital phenomena of the 
internal parts of higher animals with the image of man 
ever in the background. The chief cause of this condi- 
tion in turn is doubtless the rise of the science within 


No. 498] PHYSIOLOGY 397 


medical schools and its continued close association with 
them, as a result of which the attention of investigators 
and teachers has been necessarily focused largely upon 
internal problems. This aspect of the science is mir- 
rored in the text books, and is the chief aspect that is 
presented to the youth in his early studies. Unfortu- 
nately the university student has only a limited oppor- 
tunity to correct his early false impressions, for the 
university has not yet accorded to physiology its rightful 
heritage as a pure science. Its freedom in research 
can not be denied it, however, and popular misconceptions 
regarding its scope will disappear with its advance. The 
living of the living thing is the criterion by which the 
physiological phenomenon may be recognized. 

The ways in which the vital process manifests itself 
seem at first sight numberless and incapable of mutual 
comparison. The contraction of a muscle, the secretion 
of a glandular product, the production of a sensation, the 
growth of an organism, the orientation of a motile body 
to rays of light, the passage of a nervous impulse, respira- 
tion, the circulation of blood, the transmission of a. 
quality from parent to offspring, instinct, fatigue, a voli- 
tional act, the course of a germ disease, sleep, speech, 
laughter, thought, the digestion of food, the maintenance 
of bodily temperature, the hearing of sound, sight, the 
recognition by touch of a familiar object, memory, emo- 
tions, the inhibition of an existing action, hypnosis— at 
first thought these phenomena appear to be of quite dif- 
ferent kinds, each sui generis and incapable of com- 
parison with the others. Have they common factors? 
Is it possible to unify them? 

Through the ages various attempts have been made to 
do this. The appearance of the first of these attempts 
was nearly coincident with the culmination of Grecian 
culture. From that auspicious time down to the great 
Roman physician Galen, then across the long stretch of 
thirteen centuries, bridged by Galenic tradition, but 
barren of physiological discovery, to the rebirth of scien- 


398 THE AMERICAN NATURALIST [Von XLII 


tific, together with other, learning, and well into the 
seventeenth century, the doctrine of the pneuma, or 
spirits, reigned supreme. This doctrine was often ex- 
pressed in vague, uncertain terms, and in the hands of 
the Stoic philosophers, the Pneumatic physicians, the 
scientific men of Alexandria, Galen and minor writers, 
it was variously portrayed. The pneuma was believed 
to be an extremely subtile material agent entering the 
body with the breath, and was spoken of as ‘‘very subtle 
air,’’ ‘‘very lively and pure flame,’’ ‘‘fluid,’’ ‘‘of the 
nature of light,’’ ‘‘vapor,’’ ‘‘something analogous to the 
spirits of wine,” and so on. Each vital action was a 
manifestation of its activity. In the heart dwelt the vital 
spirits ; in the brain the animal spirits. They flowed and 
ebbed through the veins and arteries, they coursed along 
the nerves, they permeated the tissues, and they bubbled 
and effervesced. Through them the body felt and moved, 
was nourished and warmed, grew and reproduced. It 
was a genial, comforting belief, nothing was more plaus- 
ible; in its light vital actions seemed simple enough; and 
so for two thousand years the spirits danced merrily 
along. 

But there were hard-headed thinkers in the seven- 
teenth century. We may even imagine that the skilful 
experimenter, Harvey, the discoverer of the circulation of 
the blood, had his doubts. It is true that Descartes made 
free use of the spirits in his clever portrayal of the work- 
ing of the organic machine, but there were others, be- 
lievers in the machine, who contended that its Deus was 
not the pneuma. The spirit of mechanism was in the 
air. With the beginning of a rational physics, stimulated 
largely by the discoveries of Galileo and Newton, and a 
rational chemistry, freed from alchemy, there arose those 
two curious groups of Utopian theorizers, the iatro-physi- 
cists and the iatro-chemists, led, respectively, by Borelli 
and Sylvius. The one looked at the actions of the living 
being through the spectacles of the physicist, the other 
through those of the chemist; to the one vital actions 


No. 498] PHYSIOLOGY 399 


were physical phenomena, to the other, chemical phe- 
nomena. Their gaze was in the right direction, and each 
believed that he saw a great light. But like the whole 
world of science of their time, they knew too little of the 
true physics and chemistry, and their interpretations of 
organic processes, while containing a considerable modi- 
cum of truth, teemed with unwarranted hypothesis. It 
was not strange, therefore, that the iatro-movement was 
short-lived. Its influence, however, was not without 
value, for as the knowledge of physiological fact increased 
through experiment, and the world became accustomed to 
mechanical notions, the authority of the spirits became 
weakened, and gradually, very gradually, they ceased to 
be a factor in physiological reasoning. In popular 
speech, however, they persist even to our own day; for, 
as our moods change, we are in good spirits or bad 
spirits, full of spirit or lacking in spirit, high-spirited or 
low-spirited—phrases which stand as witnesses of a once 
powerful, but now discarded, physiological doctrine. 

As the spirits became deposed, scientific thinkers, dis- 
satisfied with the mechanism of the time, still groped for 
something to take their place. There were spontaneous 
uprisings of such agencies as Van Helmont’s archeus, 
Stahl’s anima, Boerhaave’s principium nervosum and 
Hoffmann’s ether. None of these long survived, and 
soon after the middle of the eighteenth century they were 
definitely replaced and the wide-spread desire for a unify- 
ing principle was for the time set at rest by the 
hypothesis of vital force. All physiologists had now 
come to realize that many of the chemical and physical 
phenomena of inorganic nature were to be observed also 
in living bodies. But they knew that the chemical com- 
position of the latter differed from that of the former, 
and for the manufacture of the vital substance and for 
many of its actions they could find no parallel outside 
of living bodies. Most of them succumbed to the com- 
pelling power of their ignorance and acquiesced in the 
assumption that a peculiar principle resides in living 


400 THE AMERICAN NATURALIST [Vou. XLII 


things, a vital force (or energy, as we would call it 
to-day), differing in nature from the forces (or forms of 
energy) that exist in non-living things. Johannes Miiller 
presented the vitalistic conception clearly as follows: 

“ Organic bodies consist of matters which present a peculiar combina- 

tion of their component elements, a combination of three, four, or more 
to form one compound, which is observed only in organic bodies, and 
in them only during life. Organized bodies, moreover, are constituted 
of organs, . . . each . . . having a separate function; . an 
they not merely consist of these organs, but by virtue of an annie 
power, they form them within themselves. Life, therefore, is not 
simply the result of the harmony and reciprocal action of these parts; 
but is first manifested in a principle or imponderable matter, which 
is in action in the substance of the germ, enters into the composition 
of the matter of the germ, and imparts to organic combinations prop- 
erties which cease at death.” 
By the same author life is characterized as ‘‘the mani- 
festation of the organic or vital force.’’ Again, ‘‘Or- 
ganic bodies participate in the general properties of 
ponderable matter. The laws of mechanics, statics and 
hydraulics are also applicable to them.’’ The applica- 
tion of these laws to them is, however, ‘‘limited,’’ from 
the circumstance that the causes of motion most engaged 
in them are essentially vital in their nature.” A few 
bold spirits, like Reil in Germany and Magendie in 
France, argued against such a conception, but they 
formed a small minority, and the physiology of the time 
became essentially vitalistic. 

This state of affairs prevailed for barely a century. 
Soon after its beginning oxygen was discovered, and the 
modern chemistry was begun. A few decades more and 
the new physics was founded on the doctrine of the con- 
servation of energy. These two discoveries with their 
momentous consequences were epoch-making for physi- 
ology. The events of the inorganic world were at last 
conceived by the human mind in a rational manner, and 
the application of such conceptions to vital processes was 
not delayed. The assumption of a specific vital force 
was seen to be unnecessary. Men began to talk of vital 
phenomena in terms of the new sciences, and physiology 


No. 498] PHYSIOLOGY 401 


began to be defined as tlie science of the physics and 
chemistry of living things. Such is the prevailing con- 
ception to-day. 

Is the vital process more than physics and chemistry? 
Two facts stand out strongly in the physiology of the 
present day. One is the constant extension of physico- 
chemical principles into the explanations of hitherto mys- 
terious functions; the other the seeming inadequacy of 
those principles to explain other functions. In their atti- 
tude toward this apparent inadequacy physiologists, while 
disavowing with almost entire unanimity their belief in 
the vital force of a century ago, may be said to be col- 
lected at present into two camps. By far the majority, 
while not denying the existence of puzzling problems, are 
yet possessed of an optimistic spirit and look forward 
with serenity to the unraveling of the mysteries of the 
organism, as the mysteries of the inorganic become more 
clear. They look at life, not as a distinct entity permea- 
ting and vitalizing a complex machine, but rather as the 
sum of the activities of that machine. In the opposite 
camp there are a few souls who, though they too have 
cast off the dross of the old conception, are rendered 
impatient and despondent by the occasional failure of 
present knowledge to explain, and they fly for refuge to 
a refined and essentially inexplicable vital residuum. 
They have succumbed to the inevitable reaction that 
follows rapid progress. But they are not vitalists, they 
say, at least not paleo-vitalists: they are neo-vitalists. 
Into the intricacies of neo-vitalistie views and into the 
shades of difference existing between them it is not oppor- 
tune here to go, for they exert practically no influence on 
the physiology of the time. The hopeful investigator 
continues his endeavors, and with success, to interpret 
vital processes in accordance with physico-chemical laws. ` 
It seems to me that this is the most promising method. 
For less than one hundred years has it avowedly been in 
vogue, and these have been the years of most rapid ad- 
vance. In this time many mysteries seemingly inex- 


402 THE AMERICAN NATURALIST (Von XLII 


plicable have been clarified. “It is futile to deny future 
rapid progress along the same lines, and the solving of 
problems that now defy the ingenuity of the experi- 
menter. We confess our ignorance and our frequent 
failures, but we believe that we are on the right track. 
Physics and chemistry are not completed sciences. Their 
youth indeed is hardly passed. Their greatest achieve- 
ments are probably yet to come. If what we know of 
physical mechanism to-day is not sufficient to insure us 
an understanding of the physiological machine, then let 
us look to what we shall learn to-morrow. Whatever the 
ultimate outcome, the solace of the vitalistic conception, 
it seems to me, should be resisted until we are prepared 
with full knowledge to maintain the final inefficacy of the 
physico-chemical mode of interpretation. If such a time 
ever arrives, it must necessarily be far in the future. 

If the vital process be capable of a physico-chemical 
interpretation, it is at once understood that the methods 
of the physiologist must be the methods of physics and 
chemistry. And this is the case. In the physiological 
laboratory we employ the same methods that are used 
in the physical and the chemical laboratories, modified 
only in so far as is necessary to adapt them to the ma- 
terial employed for study and the specific problems to 
be solved. Specific physiological-apparatus of precision 
in great variety has been devised, and specific methods 
of using it. But the apparatus and methods are physical 
and chemical in essence. The physiologist’s material for 
study must necessarily be living material, except in so 
far as it is possible to deduce the vital phenomenon from 
the phenomena of non-vital substances—a procedure 
which, though often necessary, as is especially the case 
in much of the work of the chemical physiologist, is a 
procedure of limited value. In external and in much of 
internal physiology the living organism is used intact. 
With many problems of internal physiology, however, 
the method of vivisection must be employed—a method, 
which, notwithstanding the occasional charges of the un- 


No. 498] 2 PHYSIOLOGY 403 


informed, does not in either its theory or its practise 
imply cruelty or inhumanity. 

Physiology has long since passed the stage where un- 
aided observation alone is of value, and has become pre- 
eminently an experimental science. It is the task of the 
experimenter to alter one or more of the conditions under 
which the phenomenon occurs, to observe its change, if 
such appears, and thus to throw light upon the nature of 
the phenomenon itself, its relation to both its original and 
its changed conditions, and its causes. Herein lies the 
enormous difficulty of physiological work. The vital 
process is of a complexity unapproached, much less 
equaled, in the inorganic world. Living substance is 
never exactly the same at two successive periods. It is 
ever in unstable equilibrium, the seat of constant change, 
of augmentations and depressions, of physical and chem- 
ical mutations, and of what we in our ignorance call spon- 
taneous activities; and the conditions of its activities are 
manifold and often obscure and unsuspected. To main- 
tain the majority of these conditions intact, while alter- 
ing one or more, is a superhuman task, one that is ap- 
proached, but probably never realized in its entirety. 
The physiologist is thus constantly baffled in his pursuit 
of the desired object, and must needs exercise unwonted 
patience in the face- of not infrequent failure. His 
progress is slow and his results can only approximate the 
mathematical exactness of the experimenter who deals 
with stable non-living matter. 

Since the time when physiology assumed its physico- 
chemical aspect and entered upon its modern phase, what 
has been the trend of its research? Its energies were 
first directed chiefly to the study of the mechanical and 
other physical problems of the organs of vertebrate ani- 
mals. The electrical method of stimulating living sub- 
stance. was devised, by which the latter can be made to 
act at the will of the experimenter—a method the im- 
portance of which can scarcely be overestimated. The 
graphic method was early introduced and has been de- 


404 THE ‘AMERICAN NATURALIST  [Vou. XLII 


veloped to the greatest refinement. By its use organic 
movements can be recorded graphically, and can then be 
easily analyzed into their space and time components and 
be studied at leisure. The working of the organs of the 
mammalian body, considered as physical machines, is 
now fairly well understood, although specific problems 
within this field are still being actively investigated. 
Very exact computations have been made of the amount 
of energy given off by the body in the form of heat 
and of muscular work, and it has been found to cor- 
respond very closely with the income of energy derived 
from the food and whatever bodily material may be con- 
sumed during the experiment. The principle of the 
conservation of energy applies as well to the living as to 
the non-living machine. 

Chemical physiology, or, as it is now often called, bio- 
chemistry, developed gradually during the last century 
but did not become prominent until the last decade. It 
occupies now a foremost place among the branches of 
biological science. Much biochemical work is morpho- 
logical; the determination of the chemical constituents 
and structure of substance once living, from which infer- 
ences may be drawn as to the chemical nature of living 
substance. Unfortunately, living substance can not be 
chemically analyzed directly, since all known methods at 
once kill it, and there is left only the non-living proteins, 
carbohydrates, fats and other organic and inorganic com- 
pounds, the individual bricks, or, better, cleavage 
products of the complex unity. In determining these and 
their relationships great progress has been made, but we 
of the present are far removed from that state of smug 
satisfaction of some of the earlier investigators, to whom 
a living body represented only so many molecules of car- 
bon, oxygen, nitrogen, hydrogen, sulphur and phos- 
phorus. The problems of the chemical physiologist, as 
distinguished from the chemical morphologist, are in gen- 
eral the problems of metabolism,—which the Germans 
have aptly styled ‘*Stoffwechsel’’—the chemical changes 


No. 4983 PHYSIOLOGY 405 


undergone by matter in the process of living, its building 
up and its breaking down, its anabolism and its katab- 
olism. The intricacies of metabolism can scarcely be 
conceived by one not familiar with the attempts to follow 
them, and the biochemists deserve much credit for the 
ingenuity of their methods. They have been most suc- 
cessful in determining and isolating the multitudinous 
katabolic products of vital activity, both the intermediate 
and the final products, and in discovering clues to the 
individual steps in the katabolie process. They have 
even succeeded in making synthetically many of these 
vital products, an achievement which was inaugurated by 
Wohler in 1828 in the manufacture of urea. The labora- 
tory synthesis of vital products has become, indeed, 
almost a daily occurrence and has hence lost its former 
miraculous appearance. It is not, however, certain that 
the laboratory methods and the physiological methods 
employed in such synthesis are identical. The steps of 
the anabolic process are still obscure, and until they are 
better known we can hardly look forward with confident 
satisfaction to the artificial manufacture of living sub- 
stance. Yet physiological alchemists do exist, and the 
successful making of ‘‘life’’ has been heralded more than 
once to a sensation-loving world. Such an achievement 
is for the present only an idle dream, serving to gently 
and pleasurably titillate the cerebral -cells of the 
dreamers. 

Of recent years physiological physics and physiological 
chemistry have come to meet on common ground within 
the realm of the new science of physical chemistry. It 
has come to be clearly recognized that living substance 
consists of organic colloidal, or jelly-like, material, per- 
meated by inorganic matter. The colloidal matter seems 
to consist of enormous complex molecules and aggregates 
of molecules; the inorganic matter partly of small, 
simpler molecules, and partly of ions, which are atoms or 
groups of atoms charged electrically. As the life process ` 
goes on, the living substance being now in a state of 


406 THE AMERICAN NATURALIST (Vou. XLII 


activity, now in a state of rest, there is a constant chem- 
ical and physical interplay between the two material con- 
stituents, and a constant interchange between them and 
the surrounding medium, in which the laws of osmosis 
play a prominent part. The careful investigation of the 
nature of these internal and external exchanges seems to 
be illuminating many time-honored physiological enig- 
mas, such as absorption, secretion, excretion and other 
instances of the passage of substances through mem- 
branes, the electrical phenomena of tissues, the nature 
of the nerve impulse, the fertilization of the ovum, and the 
general nature of chemical changes within protoplasm— 
enigmas which have been constantly quoted in support of 
the vitalistic conception. But we should not be tempted 
by success along these lines to claim, as is sometimes done, 
that the life process is merely ionic or electrical or osmotic 
in nature. In investigating physiological problems by: 
the aid of modern physical chemistry, we seem to be 
brought at times periously near the electron theory of 
matter, and we are tempted to hazard the guess that 
the establishment of that theory would place the physi- 
ologist under renewed obligations to the physicist. 

The study of ferments, too, is assisting—strange, in- 
numerable, intangible bodies of uncertain nature, which, 
present in minute, almost imperceptible, quantities, seem 
to facilitate vital chemical actions without entering di- 
rectly into them. In the early years ferments were 
recognized as mediating the processes of digestion, and 
but few of them were known. Of late their number has 
been enormously increased, and a corresponding number 
of intracellular. or extracellular chemical processes has 
been ascribed to their action. Each has its own specific 
chemical reaction to facilitate, and, in many cases at least, 
their action is reversible, i. e., one and the same ferment 
ean aid both the decomposition of a complex substance 
into its constituents and the synthesis of those constitu- 
ents into the complex substance. The ferments that 
function in vital processes are products of living matter, 


No. 498] PHYSIOLOGY 407 


but recent research makes it increasingly clear that they 
act merely like catalytic agents of inorganic origin. The 
study of ferments has its dangerous aspect, for more than 
one investigator, with an eye single to their universality 
and efficacy, has in his cyclopean enthusiasm come to 
suspect that all the chemical processes of living organ- 
isms are mediated by them, and has even been led to 
make the narrow and unwarranted assertion that life 
itself is merely ferment action. 

The discovery of protoplasm and the establishment of 
the cell theory have exercised a profound influence on the 
science of function. Until nearly the middle of the last 
century physiologists were in a sense groping in the dark, 
for the reason that although they were endeavoring to 
unravel the mystery of living substance, they had no 
conception of the real nature of that substance. When 
the times were ripe they were quick to recognize the value 
and significance of the new discoveries, and, indeed, 
played valuable parts in formulating and establishing the 
new doctrines. ‘With the clear recognition of a definite 
substance as the physical basis of life, their energies 
were more definitely directed than before. One result 
of this has been the increasing and powerful growth, 
during the latter part of the last century and the early 
years of this, of general physiology. The rise of general 
physiology represents a movement away from the earlier 
study of the mechanics of organs, toward that of the 
vital phenomena of living substance itself, irrespective 
of its special position within the organism. General 
physiology is preeminently the physiology of to-day, 
whether its point of view and methods be physical or 
chemical. 

The principle of organic evolution is in its essence a 
physiological principle. It represents a great physio- 
logical experiment which nature has been making since 
the beginning of living things, and is continuing to make. 
But the discovery of the facts and principles of organic 
evolution and the establishment of its theory have been 


408 THE AMERICAN NATURALIST [Vou. XLII 


accomplished only in small part by professed physiolo- 
gists. Not even has the evolution of function—a field of 
great possibilities—been explored, except in a few small 
and isolated spots. The necessity of properly controlled 
experimentation in settling the vexed problems of evolu- 
tion is, however, at last being recognized, and the next 
few decades promise to witness great advances in the 
discovery of the ways in which nature has made her 
great experiment. 

It is not strange that with its intricacies and peculiar 
difficulties the solving of the problems of nervous func- 
tion has proceeded slowly. The facts that nervous func- 
tion is a property of the nerves, and that the brain is the 
seat of the mind were probably first capable of scientific 
proof by the Alexandrians in the fourth century before 
Christ. The two great functions of sensation and motion 
were also recognized by the ancients, but that they were 
mediated by different nerves was first demonstrated by 
Sir Charles Bell, so late as 1811. The idea of the specific 
energy of nerves—a phrase which means specific ac- 
tivity—or the general principle that each nerve has 
specific functions with which it always responds, no 
matter how stimulated, was definitely proposed by 
Johannes Miiller in 1826 for the nerves of special sense, 
and later was generalized for other nerves and other 
tissues. Since then great progress has been made in 
discovering by experiment the specific functions of indi- 
vidual nerves and in formulating therefrom theories of 
the general functions of nervous tissues. That different 
nervous activities are associated with different portions 
of the brain was early surmised, and before the middle 
of the past century such important nervous centers as 
those controlling respiration and the beat of the heart 
became located. Since then the nervous mechanism of a 
host of unconscious organic processes has been discovered. 
That the psychice portion of the brain does not function 
as a unit, but consists rather of a complex group of 
nervous organs, each with its specific functions—a fact 


No. 498] PHYSIOLOGY 409 


that is of great moment in elucidating the relations of 
brain and mind—has been known for only a little more 
than thirty-five years. For it was in 1871 that Fritsch 
and Hitzig, by stimulating specific small areas of the sur- 
face of the cerebrum and obtaining in response specific 
muscular movements, first demonstrated a specific cere- 
bral localization of functions. Since then the task of 
mapping out the outer layer, or cortex, of the cerebrum 
of a few mammals and man into centers, joined by nerve 
fibers with specific organs of the body and employed for 
the control of separate groups of muscles and for the 
work of the special senses, has proceeded to a consider- 
able degree. Thus, we are now able to point to a 
certain portion of one of the convolutions of the cerebrum 
and say that its nerve cells, or neurones, mediate the voli- 
tional act of contracting one’s biceps muscle; we can say 
that the neurones in other localities mediate the separate 
acts involved in locomotion; in others, the changes of 
facial expression; and in still others, the enunciation of 
thoughts in the form of spoken words. We know with 
considerable exactness the positions of the separate 
centers for sight and hearing; less exactly those of the 
other special senses. Besides the sensory and motor 
centers, evidence points strongly toward the existence 
also of cortical regions which are elaborately joined to 
one another and to the sensory and motor regions by 
means of innumerable nerve fibers, and the function of 
which is to correlate, harmonize or associate the work of 
the sensory and motor centers. Such association centers 
thus help to mediate the more complex psychical phe- 
nomena, such as memory and the association of ideas. 
We can even formulate helpful hypotheses of the neural 
accompaniments of various psychoses. According to 
James’s theory of the emotions, for example, the per- 
ception of the automobile about to run us down leads to 
the feeling of fear only through the mediation of various 
organic processes, such as a quickening of the heart beat, 
pallor and trembling. The accompanying series of 


410 THE AMERICAN NATURALIST [Vor. XLII 


neural processes would consist in the activity, in turn, of 
visual sense organs, neurones conveying the visual im- 
pressions to the brain, cerebral neurones mediating the 
sensation and perception of the terrifying car, motor 
neurones controlling the peripheral muscular actions 
that are involved in the organic processes, neurones con- 
veying to the brain the impressions of altered heart beat, 
constricted arteries and trembling muscles, and lastly 
cerebral neurones mediating the feeling of fear. Because 
of its difficulty, much of the work of geographical explora- 
tion within the central nervous system is at present neces- 
sarily inexact, and moreover there is still much terra 
incognita. And even though we have thus come to know 
the gross functions of specific parts of the higher mam- 
malian and human brains, we still know all too little of 
the processes by which the different parts are coordinated 
and made to subserve the many complex needs of the 
organism. The recent work of Professor Sherrington on 
the integrative action of the nervous system is an 
admirable example of the kind of investigation that is 
needed in this field, and by its very excellence helps to 
emphasize the lack of our knowledge. The laboratories 
of physiological psychology, now numerous, are making 
many valuable contributions, especially to our knowledge 
of the mechanism of the special senses. But when I make 
a summary of what we now know of the physiology of the 
nervous system, I come to realize anew its paucity, com- 
pared with what we ought to know and shall know, I am 
confident, in the long future. Here, it seems to me, is a 
field sadly needing tillage, and one where, though tillage 
be extremely difficult, the yield is certain to be rich. ` 

All investigation here will lead up, in a sense, to the 
solving of that problem of problems, which has been for 
ages the focus of discussion and speculation, the problem 
of consciousness—‘‘at once the oldest problem of phi- 
losophy and one of the youngest problems of science.” 
For centuries it has been thought about, talked about, 
written about, and with what result? The elaboration of 


No. 498] PHYSIOLOGY 411 


hypothesis after hypothesis, which smell of the lamp— 
fabrications of the philosopher’s cell rather than of the 
physiologist’s laboratory. Almost without exception 
they are elaborate exercises in dialectics, rather than real 
portrayals of the nature of that most striking of phys- 
iological phenomena. To the physiologist they are 
almost without exception arid and unsatisfying. 
‘Words, words, words,’’ replies Hamlet to the question 
of Polonius. At first thought, the theories of dualism 
and interaction seem best adapted to the obvious facts of 
human experience: the brain and mind are two distinct 
entities usually intimately associated, and each capable 
of inducing phenomena in the other. But deeper brood- 
ing, and especially a recognition of the mode of action of 
the non-psychie portions of the nervous system and the 
close dependence of psychic on cerebral phenomena, of 
“how at the mercy of bodily happenings our spirit is,’’ 
make us seek a more genuinely physiological explanation. 

The physiologist recognizes as the morphological basis 
of nervous actions the neurone or nerve cell, consisting of 
a compact cell body, from which radiate outward fila- 
ments, the nerve fibers. He finds in the nervous system 
of the higher animal or man millions of such neuronés 
and many more millions of nerve fibers. These constitute 
seemingly a confused and inextricable mass, but by care- 
ful study he has been able to discover an exact and 
definite, though excessively intricate, nervous architec- 
ture. He finds that the bodies of neurones act as central 
stations, to which and from which flow the nervous im- 
pulses along the nerve fibers: the incoming impulses con- 
stituting the centripetal, or afferent, or sometimes sen- 
sory, impulses; the outgoing constituting the centrifugal, 
or efferent, or sometimes motor impulses. He recognizes 
as the physiological basis of nervous action, the reflex 
action, consisting of an afferent impulse, a central 
process, and an efferent impulse. He sees reflex acts 
combined in innumerable ways, and augmented and de- 
pressed by other reflex acts. He sees many of the most 


412 THE AMERICAN NATURALIST (Vor XLII 


complicated actions of the individual performed with the 
aid of this reflex mechanism and without the aid of con- 
sciousness. He recognizes that a large proportion, if 
not the majority, of the individual’s actions are reflex 
and unconscious actions. Lastly, he finds in reflex 
mechanisms no mysterious principle, but an ensemble of 
the same physico-chemical phenomena, which in one form 
or another he finds in other than nervous tissues, and in 
which the principle of the conservation of energy holds 
good. ‘Turning now to conscious actions, he sees how 
indispensable to them, at least in the higher animal 
species and man, is a certain part of the cerebrum, 
especially the outer layer or cortex; and how the degree 
of intellectual development varies with the extent and 
complexity of this material structure. He sees how in- 
jury or disease of this part, or anything interfering with 
its proper activity, changes the individual from a sen- 
tient being into a non-thinking reflex machine. He sees 
acts, once consciously performed, now relegated to the 
unconscious reflex sphere. He sees how consciousness 
disappears in sleep, and how its manifestations vary 
under the influence of drugs. The cerebral cortex is 
composed of numberless neurones and is connected by 
afferent and efferent paths with the other portions of 
the nervous system. With these facts in mind, and 
though recognizing the intricacies of mental phenomena, 
the physiologist gets into the way of thinking that after 
all the mechanism of cortical actions is really the same 
as that of other nervous phenomena. He sees no ob- 
jective, a priori reason why an entirely new causative 
principle should be introduced to explain the action of 
this small fraction of the nervous system. Whatever its 
nature, consciousness appears to him, not as a distinct 
entity grafted on to certain nerve structures, but as 
merely one of the modes of manifestation of the activity 
of those structures, just as chemical, thermal and elec- 
trical phenomena are other modes. Being thus one of the 
signs of nervous activity; the physiologist finds it difficult 


No. 498] PHYSIOLOGY 413 


to see how consciousness can act as a cause of nervous ac- 
tivity, any more than can the heat given off in such ac- 
tivity react to produce itself. The physiologist sees that 
nervous systems, with all their functions, have undergone 
an evolution; he recognizes orders of consciousness—a 
low, simple, gradual beginning, he knows not where, a 
progressive increase in complexity. as nervous systems 
complicate, and the final culmination in self-conscious 
man. The relations of consciousness in its simplest form 
to the nervous system seem to be the same in kind as in 
the human being. For the physiologist, looking at the. 
matter in this light, Huxley has probably formulated the 
best working hypothesis in his famous essay, ‘‘On the 
Hypothesis that Animals are Automata.’’ After a lucid 
analysis of the actions of animals lower than man, he 
says: 

“The consciousness of brutes would appear to be related to the 
mechanism of their body simply as a collateral product of its working, 
and to be as completely without any power of modifying that working 
as the steam whistle which accompanies the work of a locomotive 
engine is without influence upon its machinery. Their volition, if 
they have any, is an emotion indicative of physical changes, not a 
cause of such changes.” 

And later: 

“Tt is quite true that, to the best of my judgment, the argumentation 
which applies to brutes holds equally Lag of men; and therefore that 
all states of consciousness in us, as in them, are immediately caused 
by molecular changes of the brain sibel It seems to me that in 
men, as in brutes, there is no proof that any state of consciousness is 
the cause of change in the motion of the matter of the organism. If 
these positions are well based, it follows that our mental conditions 
are simply the symbols in consciousness of the changes which take place 
automatically in the organism; and that, to take an extreme illustration, 

e feeling we call volition is not the cause of a voluntary act, but the 
symbol of that state of the brain which is the immediate cause of that 
act. We are conscious automata.” 

Objection after objection has been raised to the autom- 
aton hypothesis. It has been dialectically disproved 
many times. Its upholders have been charged with all 
the sins against logic, common sense, lucubration, spiritu- 
ality and orthodoxy. And yet it will not down, for of all 
hypotheses it seems to accord most closely with the facts 


414 THE AMERICAN NATURALIST (Vou. XLII 


of neural physiology, as we know them to-day. It may 
perhaps prove to be not a finality; but whether in the 
distant future it be found correct or incorrect, it is from 
its general standpoint, it seems to me, that the phys- 
iologist of the present epoch can do his most helpful 
experimental work. The problem of consciousness 
should be taken into the physiological laboratory, and the 
conditions of the manifestation of psychic phenomena 
should be investigated by laboratory methods. All 
mental processes, even to the last degree, are dependent 
on and have their basis in brain processes. The physi- 
ologist should study in minute detail the cerebral process 
of each mental act. He can thus inform the psychologist 
as to the conditions under which psychic phenomena 
occur. ‘‘An individual fact is said to be explained,” 
says John Stuart Mill, ‘‘by pointing out its cause.” And 
again, ‘‘The cause of a phenomenon is the assemblage of 
its conditions.’’ In this sense the explanation of con- 
sciousness, it would appear, ought to come, sooner or 
later, from the physiologists. 

I have spoken of the physiological aspect of other sci- 
ences. Pathology, the science of disease, or, in other 
words, perturbed function, is peculiarly close to physi- 
ology, for there is no sharp line of demarcation between 
the normal and the abnormal. We may assume the suc- 
cessive chemical substances involved in a certain progres- 
sive physiological act to be represented by the series A, 
B, C, D, in which A is the substance from which the chain 
proceeds. By analytic and synthetic processes A gives 
rise to B, B to C and C to D, which is the final end- - 
product of the metabolism. Even with the same quantity 
of A and the same strength of stimulus, the quantities of 
B, C and D produced in successive repetitions of the act 
_ may vary considerably, owing to unknown factors. It is 
only when the intermediate or final products become 
markedly increased or diminished in quantity in com- 
parison with their usual amounts, that we speak of the 
function as pathological. The excitability of cells may be 
greatly augmented or diminished and still be within the 


No. 498] PHYSIOLOGY 415 


limits of the normal. <A tissue may grow excessively, as 
in tumors, or may waste away, and yet normal function ` 
be not seriously interfered with until remote limits are 
passed. Bacteria may live physiologically within an 
animal body. They produce and cast off toxins, which 
intrinsically are poisonous to the cells of their host. 
These, however, cause a physiological production of anti- 
toxins in the body cells. So long as the antitoxins are 
sufficient in quantity and strength, they neutralize the 
poisonous toxins. If the latter get the upper hand they 
augment or depress the physiological activities of the 
cells of the host, and we speak of the result as a perturba- 
tion of function. The power of the organism to adapt 
itself to changed conditions and to maintain its physi- 
ological status is little short of marvelous. When, in 
spite of all endeavors, the physiological status is over- 
whelmed, then is the time for the pathologist to investi- 
gate and the physician or the surgeon to attempt to cure. 

As in the biological sciences, so in the medical art, 
there exists a distinction between the morphologist and 
the physiologist, between the surgeon and the physician. 
The surgeon is the medical morphologist. His task is to 
remove diseased or injured tissue, to reunite separated 
structures, to restore structure or stimulate to its restora- 
tion, in short, to make structure normal, so that normal 
function may follow. The physician, on the other hand, 
is the medical physiologist. It is his endeavor to restore 
normal function. His life-long labor is an exercise in 
physiology. He should know his physiology as the sur- 
geon should know his anatomy, minutely and to the last 
degree. He should know what health is before he tries to 
restore it. We all realize how rarely this ideal is 
reached, and we all have experienced the dire results of 
medical empiricism. Huxley likens nature and disease 
to two men fighting, the doctor to a blind man with a 
club who jumps into the mélée, and strikes out right and 
left, sometimes hitting disease and sometimes hitting 
nature. Would not his blows be more telling if he were 
quite sure which of the combatants were nature and which 


416 THE AMERICAN NATURALIST [Vou XEN 


disease? Wherein he fails to avail himself of present 
knowledge he is culpable. And yet he is not to be 
charged with the whole burden of his failure to cure. 
Some of this should be shared, I regret to confess, by the 
physiologists, for they still know too little of the normal 
action of the vital mechanism. So far is this true, that 
I am convinced that one of the surest and quickest means 
of inaugurating a rational and effective art of medicine 
is through the advancement of physiological discovery. 
All physicians must be in part empiries until the physi- 
ological millennium is ushered in. 

If I have been understood aright, my hearers will have 
perceived that with a mighty subject matter which is pre- 
eminently its own, physiology extends a leavening influ- 
ence into a host of other sciences and medicine as well. 
It is an unusually good example of the typical pure sci- 
ence, with its outlying affiliations and applications. Like 
many another natural science, its rise, growth and early 
nurture were under the protecting wing of medicine. 
The physiologists of the early years, when their science 
was crystallizing out of the common mass of scientific 
knowledge, the men who first formulated its principles, 
and they who in later years developed it, were, with few 
exceptions, men of medical training who were under the 
influence of medical traditions and were guided by the 
medical spirit. In recent years the ties of the old tradi- 
tions have been loosened, and the science is passing out 
from the parental shelter into the illimitable atmosphere 
of scientific freedom. Its aspirations in research are un- 
hampered. Its achievements in research, in so far as it 
constitutes an academic theme, are limited by the fact 
that, except in a few isolated cases, physiology is still 
regarded by the university as primarily a medical science 
and its laboratories are housed in medical schools. This 
is a relic of early history. In consequence physiology 
must constantly breathe the medical atmosphere and 
must be influenced, whether it will or no, by medical 
ideals. This is not to be deprecated from the standpoint 
of physiological medicine, and the reciprocal advantage 


No. 498] PHYSIOLOGY 417 


to physiology itself in this one aspect is also great. But 
this now anomalous state of affairs leads directly to two 
consequences: namely, first, that the broader biological 
aspects of the science are less dwelt upon than otherwise 
would be possible; and secondly, that where such aspects 
have been investigated the work has been done largely by 
men not professed physiologists and usually lacking the 
latter’s exact training as experimentalists. The cus- 
tomary academic position of the science thus imposes a 
certain restraint upon physiological progress, and delays 
its full fruition. 

It is idle to try to predict the ultimate fate of the 
science that is attempting to make clear the vital process. 
To some minds it is attractive to speculate, and even to 
dogmatize, concerning the limits of natural knowledge. 
The present task of the physiologist is to investigate, and 
continue to investigate, ceaselessly and fearlessly, with a 
spirit ever fresh and hopeful, seeking only the elusive 
truth, unmindful of the limits of natural knowledge and 
undeterred by the fear that the mystery of life will ever 
remain a mystery. He must be content to spend his 
energies in patient laboratory research, accumulating 
facts, unifying facts and deducing laws for limited 
spheres of vital activity, and thus to lay the foundations 
for the broader generalizations that will come after his 
labor has ceased. By his constant association with the 
material substratum of the life process and the continual 
discovery of new and undreamed-of possibilities in its 
action; he gains a respect and even reverence for living 
matter which only he ean possess. None but he can 
realize and understand its supreme beauty and harmony 
and sublimity. He can not sympathize with, much less 
share, the feeling that the material is base and only the 
spirit is uplifting, for to him the material makes its up- 
lifting nobility manifest. He likes to believe, and to act 
on the belief, that no physiological problem is forever 
insoluble, and though ignorance may be long-lived, he sees 
no necessary reason for an ultimate, eternal ignorabimus. 


NOTES AND LITERATURE 
BIOMETRICS 


Recent Contributions to Theory—For obviously necessary rea- 
sons biometric work in the past has fallen, and for a considerable 
time in the future will continue to fall into two sharply sepa- 
rated categories. The first of these is the development of mathe- 
matico-statistical methods for dealing with biological material. 
The second is the concrete application of these methods to bio- 
logical problems. Developments of higher mathematical theory 
will never be in and for themselves of particular interest to the 
great majority of biologists. Their only interest to the biologist 
exists in what they are practically good for; if there is de- 
veloped any new mode of thinking or of investigation which will 
help to solve a problem it is of importance to know about it so 
that use may be made of it. The same consideration applies in 
regard to the applications of biometrical theory. To the biologist 
who is not cultivating this particular field of research the results 
obtained in it will be of interest only in so far as they appear 
to make significant contributions, expressible in terms intelligible 
to any non-mathematically trained person, to the solution of 
significant problems. There can be no doubt that valuable con- 
tributions to biology are being made by workers in biometry. 
Further, it is believed that this fact would be more generally 
recognized than is now the case, were the methods and results 
stated in a terminology less strange and repellent to the average 
biologist than is the mathematical. In accordance with this 
belief it will be the aim of these notes to set forth as clearly as 
may be and in a non-technical way the significant advances in 
biometrical research. Recent contributions to biometric theory 
will be considered in the present note. Work in the direction of 
the application of biometrie methods to the solution of con- 
crete biological problems will be discussed in subsequent notes. 

The degree of trustworthiness of any reasoning from sta- 
tistical constants of whatever sort must ultimately depend upon - 
the values of the ‘‘probable errors” of these constants. The 
probable error is a measure of the limits of accuracy of the 
constant to which it applies. A number of recent papers deal 

418 


No. 498] NOTES AND LITERATURE 419 


with various points regarding the general theory of probable 
errors. W. F. Sheppard, in a paper giving the mathematical 
proof of his corrections for the moments of frequency distribu- 
tions, points out that theoretically the raw value of the second 
moment rather than the value obtained by applying his correc- 
tions should always be used in calculating the probable errors ‘of 
the mean and standard deviation. The present writer? shows 
by the consideration of conerete examples that the point made 
by Sheppard is not likely ever to be of any practical significance 
to the working biometrician. It makes no sensible difference in 
the actual result whether one does or does not use the corrected 
value of the second moment in determining these probable 

errors. In the same paper it is shown that a very considerable 
` error may be made by using the formula ordinarily given for the 
probable error of the standard deviation when the distribution 
of variation differs considerably from the normal curve in cer- 
tain particulars. One must always be cautious in assuming that 
a deviation from normality will be of no consequence in cal- 
culating probable errors. 

A novel and important point regarding the probable error of 
a mean has been thoroughly investigated and solved by that 
mysterious person ‘‘Student,’’® who has previously contributed 
to the pages of Biometrika under the same nom de plume. In 
passing it may be remarked that the propriety of publishing 
serious contributions to science under an assumed name seems 
questionable; one had supposed that those conditions no longer 
existed which in earlier times made such a course not merely de- 
sirable, but often indeed necessary if the same individual were to 
continue to contribute to science. To return to the point. In 
all kinds of experimental science the following type of problem 
very frequently arises; a series of say 10 or fewer experiments 
are tried under certain experimental conditions which may be’ 
denoted by the letters a, b, c, d, . . . n. A second series of equal 
extent is then tried with, say, one experimental condition changed 
so that the conditions are now q, b, c, d, n. With what 
degree of probability may it be asserted that : an 1 phadrved differ- 

1 Sheppard, W. F. The Calculation of the Moments of a Frequency 
Distribution. Biometrika, Vol. V, 4 1907. 

* Pearl, R. On Certain Points concerning the Probable Error of the 
Standard Deviation. Ibid., Vol. VI, pp. 112-117, 1908. 

***Student.’’ The Probable Error of a Mean. Ibid., Vol. VI, pp. 
1-25, 1908. 


420 THE AMERICAN NATURALIST [Vou. XLII 


ence in the results of the parallel sets of experiments is real, 
that is, is due to the changing of condition a to q and not merely 
a chance result of random sampling? On account of the sta- 
tistical smallness of such experimental series, coupled with the 
fact that the results usually deviate widely from the normal dis- 
tribution of errors, the usual theory of the probable error of a 
class frequency or of a mean fails to give an adequate answer 
to the problem. ‘‘Student’’ has done the great service of pro- 
viding formulas to cover the case. He furthermore gives a table 
of probabilities for series involving four to ten experiments, in- 
clusive, wherefrom the answer to such a question as that pro- 
pounded above may be read off at once when the experimental 
data are at hand. In the original paper concrete illustrations — 
of the use of the table are given, based on published experimental 
data in the fields of physiology and of agriculture. No par- 
ticular mathematical knowledge or skill is necessary to use this 
table and its importance to the experimental worker is obvious. 

On this same topic of probable error Pearson and Leet have 
recently made an important contribution. While the investiga- 
tion itself is of a complex mathematical character, the essential 
point is this: Suppose a number of bodily characters (say six to 
eight) to be measured in a large sample of a population. There 
are likely to be a very few individuals out of the whole sample 
that differ rather widely from all the other individuals. What 
is the probability that such outlying individuals do not really 
(i. e., biologically or genetically) belong to the population from 
which the sample is drawn, but only happen to get into the 
sample by accident? The solution to this problem is what 
Pearson and Lee attempt to give. 

Along with these investigations on probable errors is to be 
included a recent paper of Pearson’s® on the relation of past 
experience to future expectation. The nature of the problem 
discussed may be indicated by an example. Suppose that a 
sample of 100 individuals out of a population be examined and 
2 per cent. of these individuals be found to be suffering from 
some particular disease. What percentage of a second sample of 
100 may reasonably be expected to show the disease? The 

, K., and Lee, A. On the Generalized Probable Error in Mul- 
tiple Kora Correlation: Ibid., Vol. VI, pp. 5 08. 
* Pearson, K. On the Lifeanes of Past Experience on Future Expecta- 
tion. Phil. Mag., 1907, pp. 365-378. 


No. 498] NOTES AND LITERATURE 421 


answer usually given is that 2 per cent. is to be expected, with a 
probable error of a certain amount. In calculating this prob- 
able error in the ordinary way it is assumed that the distribu- 
tion of chances is given by the normal or Gaussian curve of 
errors. Pearson shows that this is not true except (1) when the 
first sample is indefinitely large in proportion to the second, and 
(2) when the characteristic does not occur in either a very large 
or very small percentage of the population. He then proceeds to 
develop general formule from which one may determine first 
the average expectancy for the second sample and its true prob- 
able error, and second the frequency of future samples having 
varying degrees of the characteristic under consideration. These 
methods are fully illustrated with numerical examples. The 
usefulness of the methods for biological work may be indicated 
by an example. Suppose that in a sample of 200 tadpoles, 106 are 
males and 94 females. Suppose, further, that in a second sam- 
ple of 300 collected later in the season the proportion is 171 males 
to 129 females. Is it to be concluded that between the collections 
some factor has come into operation tending to the greater pro- 
duction of males? Or, on the other hand, is the proportion ex- 
hibited in the second sample what might be regarded as a rea- 
sonable chance deviation due to random sampling in a population 
wherein the sex, determining factors had not changed since the 
first sample was collected? The paper under discussion furnishes 
the methods whereby questions of this sort may be definitely 
answered. 

Another recent contribution of Pearson’s® furnishes new meth- 
ods of determining the degree of correlation between variates. 
The methods are adapted for use in eases where for one reason 
or another it is not feasible to use the ordinary product-moment 
method of finding a correlation coefficient. It is neither possible 
nor desirable to enter upon any detailed discussion of the mathe- 
matical features of these new methods here. Three new methods 
are given. The first, or ‘‘difference method’’ of determining 
correlation, furnishes a very simple and tolerably accurate way 
of deducing a correlation coefficient from a symmetrical (e. g., — 
homotypic) correlation table. The other two methods are con- 

° Pearson, K. Mathematical Contributions to the Theory of Evolution 
—XVI. On Further Methods of Determining Correlation. 

Draper’s Company Research Memoirs. Biometrie Series, IV, pp. 39, 
1907. (London: Dulau & Co.) 


422 THE AMERICAN NATURALIST [Vor XLII 


cerned with the problem of determining correlation from ma- 
terial arranged in ranks. The most obviously simple way of 
dealing with any mass of statistical material is to arrange the 
individuals in a long row in order of ascending magnitude of 
some character. It is not even necessary that the character be 
accurately measurable on a quantitative scale to make such a 
row. The second, and on the whole most important of Pearson’s 
new methods, shows how to deduce true variate correlation from 
the correlation of ranks. The method is less accurate than the 
usual product moment method. The third method deals with the 
determination of variate correlation from the positive difference 
of ranks. Regarding these last two methods Pearson’s general 
conclusion is ‘‘that variate correlations found by ranks may 
prove to be a useful auxiliary method of dealing with correlation, 
when it is needful to give a rough answer to a problem in a brief 
time, or when the material itself is incapable of being accurately 
measured. ’’ 

In connection with this matter of the analysis of statisties by 
the method of ranks or grades it is of interest to note that Galton 
has recently published a table’ of deviates of the normal curve 
which will be found useful in practical statistical work. In the 
text accompanying the table (which is calculated by W. F. 
Sheppard) the use of the method of grades in dealing with ma- 
terial not susceptible of exact numerical measurement is dis- 
cussed. 

Of value for practical biometrical computing work is an edi- 
torial note* in the current number of Biometrika giving an easily 
calculated and extremely exact formula for the T function. This 
function is frequently used in statistical work, particularly in 
curve fitting. 

RAYMOND PEARL. 


PROTOZOA 
Some Ameba Studies.—The amcboid organisms include a vast — 
number of minute bits of glairy protoplasm which live in widely 
different places sometimes free in ponds and pools, sometimes con- 
fined as parasites, to the narrow limits of a single tissue. To 
T Galton, F. Grades and Deviates, Biometrika, Vol. V, pp. 440-406, 
1907. 
*On a Formula for Determining T(x +1). Ibid., Vol. VI, pp. 118-119, 
1998. 


+ 


No. 498] NOTES AND LITERATURE 423 


group all of these living things under the one generic name of 
Ameeba is to confess the weakness and artificiality of classifica- 
tion. Schaudinn' attempted to bring some order into the group 
by adopting Cassagrandi and Barbagallo’s generic name Enta- 
mæœæba to cover the ordinary parasitic forms of the digestive tract. 
These differ from the common Ameba proteus quite as markedly 
as do other genera of rhizopods, and whether they differ gener- 
ically among themselves is a matter to ip decided only when the 
life histories are made ou 

Notwithstanding the so of observations that are an- 
nually made on these amceboid organisms, there has been very 
little consecutive work on the changes of the protoplasm from 
beginning to end of the life cycle. Indeed, biologists would have 
extreme difficulty in picking up the thread of such a life history 
at either end, for observations and descriptions of conjugation 
or fertilization are most contradictory and confusing. The 
confusion will probably straighten out as soon as it is recognized 
that the varied accounts undoubtedly refer to quite different 
species or even genera of organisms. Schaudinn’s description 
(op. cit.) of the process of fertilization in Entameba coli was 
peculiarly daring, for autogamy amongst the unicellular animals 
was then a rare phenomenon, known to occur for a certainty 
only in Actinospherium. Some such unusual process might be 
anticipated, however, in view of the fact that despite the thou- 
sands of eyes that annually study the amceboid forms, none have 
witnessed an ordinary form of conjugation amongst them. 
Schaudinn’s excellent work on Entameba coli, safeguarded by 
long experience with different kinds of protozoa study, and 
controlled by parallel studies on free-living rhizopods of other 
types must not be lightly brushed aside as too bizarre for serious 
consideration, especially as it has been confirmed in every detail 
by Wenyon? upon Entameba (Ama@ba) muris, an intestinal 
parasite of the mouse. 

According to Schaudinn, the cell of Entameba coli, when 
mature, throws out all foreign matter and waste matter 
of its own metabolism, becomes more compact, smaller and 
spherical, and secretes a thick slightly refractive gelatinous 
membrane. The nucleus then divides by a primitive type o 

?F. Schaudinn. Untersuch. über d. Fortpflanzung d. Rhizopoden. Arb. 
a. d. Kais. Ges.-Amt., XIX, 3, 1903. 

20. M. Wenyon. Observations on the Protozoa in the Intestine of 
Mice. A. f. Prot., Supp. 1, Festband R. Hertwig, 190 


424 THE AMERICAN NATURALIST [Vou. XLII 


mitosis into two nuclei which are separated from. one another 
by the entire diameter of the cell. The nuclei then fragment, 
forming chromidia, while the cell becomes incompletely divided 
into daughter cells. In some cases the entire nucleus of each 
half disappears in the mass of chromidia granules; in other 
cases there appears to be a secretion of the chromidial substance 
as in Arcella, but in all cases a portion of the nuclear material 
is thrown out of the nucleus to degenerate. From the chromidia 
granules a new and smaller nucleus is formed in each half of the 
cell. Each then divides by a primitive mitosis into two nuclei, 
one of which degenerates, the other divides a second time and 
again one of the resulting daughter nuclei degenerates. After 
this process, which Schaudinn interprets as the equivalent of 
reduction and polar body formation in metazoa, the final encyst- 
ment takes place. The gelatinous membrane disappears and in 
its place a much more refractive cyst membrane is secreted. The 
contents of the cyst become closely united again and the two 
remaining nuclei are brought together. Then follows a. third 
division by mitosis characterized by long connecting strands 
which lie parallel with one another in the center of the cell and 
so that the daughter nuclei lie side by side in pairs. These 
paired nuclei then fuse, an eighth part of one of the original 
nuclei uniting with an eighth part of the other. Each cyst 
thus contains two fertilized nuclei, each of which subsequently 
divides twice to form eight nuclei. In this condition the 
cyst passes into the intestine of a new host, where the protoplasm 
divides into eight spores each with one nucleus. Wenyon’s 
account of Entameba muris confirms Schaudinn’s in all essen- 
tial features. 

While Amæba proteus is probably far removed, phylogenet- 
ically, from Entamoeba, there is reason to believe that the proc- 
esses of fertilization have something in common. Four years 
ago Calkins* found what he regarded as evidences of a sexual 
phase in the life history, and described the multiplication of 
primary nuclei and the fragmentation of these nuclei into 
chromidia. The chromidia were interpreted as the possible 
nuclei of future gametes, an interpretation in line with the 
processes and outcome of chromidia formation in Foraminifera, 
in Arcella, Centropyxis, Difflugia and other rhizopods. Subse- 

*G. N. Calkins, Evidences of Sexual Cycle in the Life History of 
Ameba proteus. A.f. Protist., V, 1904 


No. 498] NOTES AND LITERATURE 425 


quent observers, overlooking the fact that the stages in question 
must be very rare, have taken the ground, for the most part, that 
the evidence presented was too fragmentary to justify the con- 
clusions reached. Some, like Schubotz,t while admitting the 
chromidia, claim that the organism is not Amæba proteus, and 
that the chromidia are not evidence of a sexual cycle; others 
like Prandtl,” forgetting that the cells under discussion were 
in a period of unusual physiological activity, attempted to ex- 
plain them as pathological specimens with degenerating nuclei; 
and still others considered the scattered chromidia as MERTA 
parasites. The latter point of view was maintained by 
Prandtl’ in a publication subsequent to the one just mentioned 
and in which the history of an Ameeba-infesting parasite was 
made out. In this paper he hazarded the guess that the so-called 
multinucleate stage of Amæba proteus was in reality an ordinary 
form of Amceba infected with some species of Allogromia. "This 
idea was undoubtedly suggested by the superficial resemblance 
between Prandtl’s infected amcebe and the photographs of the 
multinucleate Amæba proteus. Added experience would un- 
questionably have altered this conclusion, but the untimely death 
of this brilliant young investigator put an end to a career ot 
great promise. 
It was probably such experience that prompted Doflein to 
refrain from suggesting the possibility of an infection of Amæba 
proteus with some species of Dangeard’s Nucleophaga. Doflein® 
found that the giant nucleus of Amæba vespertilio is a degenera- 
tion nucleus due to the presence of an intra-nuclear parasite 
Nucleophaga amebea, discovered by Dangeard in 1895, and he 
calls attention very properly to the possibility that many of 
the supposed chromidia in Ameeba and allied forms may be 
parasites or stages of parasites of like nature. A similar parasite 
in the macronucleus of Paramecium caudatum was described by 
Calkins® as an intra-nuclear parasite similar to the intra-nuclear 
+H. Schubotz. Beiträge zur Kenntnis der A. blattæ und A. proteus. 
A, J- Protist., VI, 1905. : 
randtl. Die physiologische Degeneration der Amæba proteus. 
A f: Tas. VIII, 1907. 
*H. Prandtl. Der Entwicklungskreis von Allogromia sp. A. f. Protist., 


© TF., Doflein. Studien zur MEAE der Protozoen. V. Amöben- 
studien. A. f. Protist., Supp. 1, Festband R. Hertwig, 1907. 

*G. N. Calkins. The Life letas of Cytoryctes variolæ Guat. In 
Councilman’s Studies on Variola. Jour. Med. Research, 1904. 


426 THE AMERICAN NATURALIST [Vot XLII 


phase of the smallpox organism. But between this parasite and 
the chromidia of Amæba proteus there is not the slightest trace 
of resemblance. 

Tn the earlier paper it was supposed that the chromidia stage 
is only the antecedent of the later gamete formation and that 
conjugation of gametes is the method of fertilization. In a later 
paper Calkins? described some further studies made upon the 
same material after the amcebe had been removed from the 
balsam, embedded in paraffine and sectioned. The supposed 
chromidia granules were then described as minute secondary 
nuclei which unite two by two, each couple giving rise to a 
reproductive body similar to a sporoblast. There were many 
gaps in this later account of fertilization and much remains to 
be done before the fertilization of Amæba proteus is established, 
but these later observations indicate a fundamental agreement 
with Schaudinn’s description of fertilization in Entameeba. 
Chromidia formation seems to be an expression of some deeply 
lying biological activity concerned with the germ plasm and 
with fertilization. In some forms, as Arcella, Polystomella or 
Centropyxis, the nuclei of conjugating gametes are formed by 
the coalescence of such chromidia. In Entameba coli there is 
a similar coalescence to form gametic nuclei, while fertilization 
is autogamous. In Amæba proteus the original nucleus of the 
cell divides repeatedly, the resulting nuclei break down into 
fragments, each of which is a complete gametie nucleus. Fertil- 
ization is again autogamous and chromidia formation s. str. 
absent. 

It must not be forgotten in comparative studies of this kind 
that the organisms are widely different and that the expression 
of the fundamental biological activity underlying chromidia 
and fertilization is worked out in widely different ways. This 
obvious and trite observation has not been heeded in a recently 
published work on parasitic rhizopods by E. L. Walker.2° Car- 
ried away, apparently, by success in raising amceboid organisms 
in large quantities by using artificial culture media recommended 
by Musgrave and Clegg, Walker has allowed to slip away a 
valuable opportunity to contribute something new to our knowl- 
edge of intestinal forms of rhizopods, while, on the other hand, 

*G. N. Calkins. The Fertilization of Amæba proteus. Biol. Bull., 
XIII, 1907. 


“KE. L. Walker. The parasitic Amebe of the SEENEN Tract of Man 
and other Animals. Jour. Med. Research, XVII, 1 


No. 498] NOTES AND LITERATURE 427 


he has allowed his imagination to lead him into generalizations 
involving totally different organisms. Here is one danger of the 
use of artificial culture methods in studying protozoa. The enor- 
mous numbers obtained tend to obscure the varying phases of 
vitality that characterize the life cycle of protozoa. The study 
of protozoa, even when it is possible to apply bacteriological 
methods, is fundamentally different from bacteria study. The 
latter dependent upon growth conditions, colony formation, re- 
actions to media, ete., are essentially physiological. Protozoa 
study, on the other hand, is essentially morphological and is 
based upon the structures of the protozoan cell, involving all 
changes in cell structure which an individual (in the cyclical 
sense) undergoes during various phases of vitality. Hence it 
becomes necessary, first of all, to know the life history of a 
protozoon and the fundamental structures which its protoplasm 
assumes at different periods of vitality. Mere number of cells 
in any given phase is not satisfactory and here is where Walker 
falls into a trap. He fails to find stages described by Schaudinn 
and Wenyon, in his agar cultures and gives the inference at 
least that their observations were incorrect, all without taking 
the trouble to obtain his organisms in the corresponding stages 
of vitality. Schaudinn, in one set of observations to fill out the 
sexual phase of the life history, watched his material for weeks 
without finding the stages desired, and, to get them, finally 


tained what he wanted. This heroic method of procedure is 
not absolutely necessary, for abundant material may be obtained 
by inoculating lower animals; even such experiments, however, 
were not made apparently or, if made, not deseribed by Walker. 
Such neglect vitiates all criticism or comment by the author, 
of conclusions of others regarding the sexual cycle of intestinal 
rhizopods and a fortiori of free-living Amæba proteus, an en- 
tirely different kind of organism. 

Not even in regard to the ordinary vegetative phases of his 
organisms does Walker do justice to the material. The un- 
doubted reproduction by budding is entirely overlooked; the 
term ‘‘spore’’ is misused throughout and the ‘‘extrusion’’ of 
fully formed reproductive bodies is very questionable. If such 
a method of endogenous bud-formation actually obtains, then, as 
an entirely new phenomenon in these rhizopods, it certainly 


428 THE AMERICAN NATURALIST  [Vou. XLII 


deserves more than the superficial description which the author 
gives. It is difficult to conceive how the budding process could 
have been overlooked, for in Entamceba under culture on agar, 
this process is apparently the most common method of reproduc- 
tion. It is quite probable that development of the extruded so- 
called ‘‘spores’’ as described is the actual development of such 
buds. The finer details of structure were not made out, the origin 
of chromidia granules and their fate are not described, owing, 
possibly, as the author admits, to faulty technique (p. 418). 
Much dependence is placed upon the cyst, but there is no evi- 
dence to indicate that the author is cognizant of the difference 
between temporary and permanent cysts. Many instances 
among protozoa might be cited of the wide difference existing 
in the two types and in the same species, and Schaudinn and 
others have previously called attention to these differences in 
the parasitic rhizopods.. Hence the eyst, as a feature in the 
identification of species as Walker gives them, loses it value. 
Walker’s long list of species finally, while a convenient summary 
of the described ameeboid parasites, can not be accepted as 
established, and his several ‘‘new’’ species must share the same 
fate, for in no case has the full life history—the only adequate 
basis of species—been made out. When the full history is 
worked out, these many so-called species will probably be re- 
duced to mere varieties, or to a few species of the genus 
Entameeba. 
G. N.C. 


EXPERIMENTAL ZOOLOGY 


Regeneration.'—Professor Korschelt has brought together 
in compact, yet readable form, the more important results 
on regeneration and transplantation in animals and plants. 
No small amount of discrimination is required to put into 170 
pages all the results so far obtained on regeneration both of 
animals and of plants; yet Professor Korschelt has shown un- 
usual judgment in selecting the essential and typical results of 
the old and the recent work. Necessarily, much detail has been 
pruned away, yet the author has succeeded in bringing into 
proper correlation many widely scattered facts. The more 
theoretical and analytical sides of the problem occupy a very 
- 1 Regeneration und Transplantation. By E. Korschelt. 1907. 


No. 498] NOTES AND LITERATURE 429 


secondary place in the present treatise, yet have by no means 
been entirely left out of account. We venture to think, however, 
that the more valuable outcome of the experimental study of 
regeneration lies less in a descriptive account of what takes 
place than in the attempt to give an analysis of the problems 
involved. 

The second half of the book, some 75 pages, deals with Trans- 
plantation, or grafting, as it is more generally called. The more 
limited data in this field receive ample consideration. 

The extensive literature of both subjects is arranged under 
topical headings—an arrangement that will recommend itself 
in the present case as preferable to the more usual methods of 
giving selected bibliographies at the end of each chapter or en 
bloc at the end of the book. We ean not refrain, in passing, from 
calling attention to a slight misprint in one of the English titles 
that reads ‘‘The international factor in the regeneration of the 
tail of the tadpole.’’ 

Passing to a more detailed examination of Professor Kor- 
schelt’s book, we find that while the formation of new growths in 
plants—more especially those cases where the new growth does 
not come from latent buds—is included under the heading of 
regenerative processes, the development of parts of the egg and 
the regulative changes that take place in isolated blastomeres 
and in fragments of the segmented egg are not included, despite 
the fact that the restoration of the whole form by a nucleated 
piece of a protozoon is described in some detail. Such limita- 
tions of the subject are, in the opinion of the reviewer, rather 
arbitrary; for, while it is unquestionably advantageous to limit 
certain fields, and to bring together certain groups of more 
closely related subjects, the fundamental problems of regenera- 
tion involved in all cases where a part produces a new whole have 
so much in common that the study of the subject gains rather 
than loses by taking as broad and as general an aspect of the 
subject as possible. 

The most recent work on the regeneration of entire plants from 
leaves, as illustrated by the work of Goebel, Hildebrand, Winkler, 
Voéchting, Nemec, Figdor and others is given in some detail in 
the opening chapter. It is pointed out that in many of these 
cases the new plant does not come from preformed buds, and not 
even from merismatie tissue in the case of Drosera according to 

- Winkler, but directly from one or more cells of the epidermis of 


430 THE AMERICAN NATURALIST — [Vow XLII 


the leaf. The problem of localization of the new growth in such 
cases is not discussed, nor have we, in fact, as yet any sufficient 
clue to the matter. 

The growth of broken erystals in-saturated solutions is dwelt 
on at some length. The remarkable similarity of this process to 
regeneration in organisms is emphasized, more especially in the 
light of the remarkable work of Lehman on fluid erystals. The 
author apparently suspends judgment concerning the interpre- 
tation of the resemblances of the two processes—whether we are 
dealing with only an analogous process or whether the two phe- 
nomena have fundamental properties in common. ‘‘Das Für 
und Wieder kann hier nicht erörtert werden.’’ 

Korschelt thinks that the loss of power to regenerate is a 
general accompaniment of the degree of organization (Organi- 
zationshéhe), yet he points out that this is not universal, as 
shown by the absence to regenerate in some forms and its pres- 
ence in other closely related ones. In fact, the time-honored 
statement of such a relation has very little weight in the face of 
recent facts to the contrary. When, for example, such a com- 
plex organ as that of the eye of a salamander can regenerate 
from a piece of the bulb, while the head of the planarian, Dendro- 
coelum, fails to regenerate behind a certain level (where no 
obvious change in Organizationshéhe is apparent) we may well 
hesitate to lay any especial emphasis on such a generalization. 

The discussion of the phenomenon of regeneration as an 
adaptation occupies only seven pages of the book. By adapta- 
tion is meant in general not so much that the process is useful—a 
fact too evident to dispute—but that in some way regeneration 
has been acquired on account of its usefulness. Our author 
would not, of course, adopt a teleological explanation, but as- 
sumes instead the supposed alternative of the Darwinian ex- 
planation of the origin of usefulness. Most students of the 
subject have rejected this interpretation on what the reviewer 
believes to be sufficient evidence. Korschelt’s somewhat cautious 
attitude is summed up in the following statements. ‘‘ Despite all 
the difficulties that have been raised one can not escape the im- 
pression that the power to regenerate and the liability to re- 
generate stand in a causal relation to each other.’’ ‘‘We find 
that it is also the opinion of competent botanists that the inter- 
pretation of regeneration as an adaptation is little to the point. 
They agree with the zoologists mentioned above in this regard.” 


No. 498] NOTES AND LITERATURE 431 


‘If we look upon the power to regenerate as a property imma- 
nent in the living substance, which seems not improbable, owing 
to its wide occurrence, we may still suppose that this property 
has within certain lines of evolution been strengthened by adap- 
tation and selection.” 

The origin of the new material from the old, the process of 
transformation (morphallaxis), the curious phenomenon of com- 
pensatory regulation, the occurrence of polarity and the develop- 
ment of heteromorphie structures are adequately dealt with from 
an objective standpoint, although in our opinion all too briefly 
considering the importance of the theoretical problems involved. 
These parts of the book are followed by a discussion of the factors 
of regeneration. The nature of the subject and the uncertainties 
of the theoretical problems involved make it difficult to treat such 
theoretical questions briefly and definitely, yet one could have 
wished that so admirable a review and so judicious a treatment 
of the descriptive processes might have been followed up by a 
more illuminating or at least suggestive discussion of the funda- 
mental problems of regeneration as the title of this section might 
lead one to expect. 

Under the heading of transplantation the grafting processes 
in plants is first briefly described. The important and recent re- 
sults of grafting in animals receive careful attention. The in- 
teresting experiments on hydra by Wetzel, Rand, Peebles and 
King are sympathetically considered, and the equally important 
work of Korschelt’s pupils, Joest and Rabes, are clearly and 
forcibly dealt with. Born’s classical experiments with tadpoles, 
that have led to so many far-reaching experiments in recent 
years, occupy, as is their due, an important place in this field. 
The later work of grafting in amphibians, especially that of 
Harrison and Spemann, is described; but the author, while re- 
ferring briefly to the important experiments of Lewes, has failed, 
in our opinion, to give them their proper place. 

The author considers in some detail the modern work of trans- 
plantation of small portions of the tissues and has brought to- 
gether in readable form the results of the literature of the sub- 
ject, that is widely scattered, often in journals little accessible 
to zoologists. Korschelt’s review will prove a useful source of 
information in such matters. 

We cordially recommend Professor Korschelt’s book as one of 
the most recent, most judicious and fair presentations of the 


432 THE AMERICAN NATURALIST — [Vou. XLII 


subjects of regeneration and grafting. The yearly reviews of 
Barfurth in the Ergebnisse fiir Anatomie und Entwickelungs- 
geschichte will supply special students with the numerous details 
that the study of regeneration is bringing to light. The more 
analytical and philosophical discussion of the problems involved 
will be found in the recent reviews and writings of Driesch. 
The general reader and layman who is less concerned with these 
details or with ‘‘the higher eriticism’’ can not do better than 
give Korschelt’s book a careful reading. 
M. 


PARASITOLOGY 


A Chinese Parasite—DLooss has recently demonstrated’ that 
under the old name ‘‘Opisthorchis sinensis”? two human para- 
sites have been confused by all save Baelz, whose differentiation 
of the two species in 1883 has been generally disregarded. For 
these forms the new genus Clonorchis is created with C. sinensis 
(Cobbold, 1875) as type. This species is the Distomuwm inocuwm 
of Baelz and is chiefly a Chinese parasite, though it occurs rarely 
also in Japan. The other species is the Distomum endemicum 
of Baelz, which now becomes C. endemicus; it is the form usually 
described in text-books, ete., as ‘‘Opisthorchis sinensis.’’ Ac- 
cording to existing records it is very common in Japan and pre- 
sumably so in Annam and Tonkin also. It seems to be confined 
to localities on the sea-shore. I would suggest that this appears 
to indicate infection through fish, as is the case with Opisthorchis 
felineus in the territory adjacent to the Baltic. 


Hu W- 
* Ann. Trop. Med. and Par., 1, 123. 


(No. 497 was issued on June 7.) 


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WALKER PRIZES IN NATURAL HISTORY 


By the provisions of the will of the late Dr. William Johnson Walker two 
prizes are annually offered by the BOSTON SOCIETY OF NATURAL HISTORY for the 
best memoirs written in the English language, on subjects proposed by a Committee 
appointed by the Council. 

For the best memoir presented a prize of sixty dollars may be awarded; if, how- 
ever, the memoir be one of marked merit, = amount may be increased to one 
hundred dollars, at the discretion of the Committee. 

For the next best memoir a prize not ENN fifty dollars may be awarded. 

Prizes will not be awarded unless the memoirs presented are of adequate merit. 

The competition for these prizes is not restricted, but is open to all. 

Attention is especially called to the following points: 

all cases the memoirs are to be based on a considerable body of original 
and unpublished work, accompanied by a general review of the literature of the 
subject. 


Anything in the memoir which shall furnish proof of "ae identity of the 
author shall be considered as debarring the essay from competitio 
3. Preference will be given to memoirs showing intrinsic p of being 
based upon researches made directly in competition for the 

Each memoir must be accompanied by a sealed asdi enclosing the 
dotor s name and superscribed with a: motto corresponding to one borne by the 
manuscript, and must rk in the hands of the Secretary on or before April ist of the 
year for which the prize is offered. 

- The Society assumes no responsibility for publication of manuscript 
submitted. 
pe FOR 1908: 

An rimental study of inheritance in snimala or plants. 2. A com- 
Se wees of the effects of close-breeding and animals or plants. 
3. A study of animal reactions in relation to habit: Bantia, 4. A physiological 

1 - 


study of one (or )sp f plants with respect to leaf variation. 5. Fertiliza 
ti d related vl i h l What proportion of a plant’s 
seasonal growth is represented in the y winter bud ? 7. A physiographic study of the 
forms and processes discoverable along a varied shore line. 8. A problem in 
structural geology. 9. A study of one or more geological horizons with a view to 
determining the different conditions obtaining at one time over a large area, as 
recorded by sediments and fossils, 

SUBJECTS FOR 1909: 


A geographic study of a district of varied features, presented as involving 
the nane relations of inorganic and organic elements, 2. A petrographic study 
of a district of crystalline rocks. 3. A paragenetic study of a mineral locality. 4. 
The conditions controlling sexual reproduction in plants. 5. Studies in the life 
history of a thallophyte, sik special reference xe sporogenesis. 6. Contribution to 
our knowledge of response in plants. 7. The fac rs governing orientation in animal 
responses. 8. The relation between primary praia secondary sex characters in 
animals. 9. The activities of the animal body in relation to internal secretions. 
Boston Society of Natural History, 

Boston, Mass., U. 8, A, 


GLOVER M. ALLEN, Secretary 


VOL. XLII, NO. 499 


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THE 


AMERICAN NATURALIST 


VoL. XLII July, 1908 No. 499 


A NEW MENDELIAN RATIO AND SEVERAL 
TYPES OF LATENCY 


DR. GEORGE HARRISON SHULL 


STATION FOR EXPERIMENTAL EVOLUTION OF THE CARNEGIE INSTITUTION, 
CoLD Spring HARBOR, N. Y. 


INTRODUCTION 


In two papers presented before the Botanical Society 
of America at its annual meetings in New Orleans (1905) 
and New York (1906), I discussed the question of latency 
as exemplified by certain color-characters in common 
garden beans (Phaseolus vulgaris). These papers were 
published in reversed order in Screncz, May 7 and 24, 
1907. 

It was shown that certain characters appeared in the 
hybrids, of which no indication was found in either 
parent, and the origin of these novelties was traced to 
unseen Mendelian units possessed by the white bean 
(White Flageolet) used in the various crosses. The new 
characteristics were a mottled color-pattern, M, and a 
blackener or enzyme, B, which acts upon brown or yellow 
pigments, P, to produce anthocyan, the presence of the 
latter resulting in black or various shades of violet to 
reddish purple seed-coats. It was assumed that the 
brown and yellow beans used in these crosses have the 
gametie formula, Pbm, the black bean the formula, PBm, 
and the white the gametic formula, pBM. In crossing 
the white bean with any of the self-colored beans the 
three dominant units were brought together, resulting 

433 


» 434 THE AMERICAN NATURALIST [ Vou. XLII 


in a purple mottled F, (PBM). It was the occurrence 
of this purple mottled F,, no matter which pigmented 
bean was used, that led to my conclusions regarding the 
latency of a mottled color-pattern and a melanizer in the 
white bean, and also to the prediction that F, would 
consist of the five forms—purple mottled, black, brown 
mottled, brown (more properly, dark orange), and white, 
—in the well-known tri-polyhybrid ratio, 27:9:9:3:16. 


Aw UNEXPECTED Ratio AND ITS SIGNIFICANCE 

At the time my last report was made, the count of the 
F, hybrids had not been completed, but the five predicted 
types were clearly presented. On summing up the results 
of the census of the numerous F, hybrid families, it was 
found that the ratio was not as predicted, but the mottled 

and self-colored beans occurred in all cases in ap- 
proximately equal numbers, resulting in the ratio 
18:18:6:6:16, or, reduced to its lowest terms, 9:9:3:3:3%. 
To be exact, in the cross between Ne Plus Ultra (dark 
orange yellow, called ‘‘brown’’ in my notes) and White 
Flageolet, 10 families gave 133 purple mottled, 114 black, 
40 brown mottled, 50 brown, 105 white, and 6 doubtful. 
Similarly, in the cross between Long Yellow Six Weeks 
(light yellow) and White Flageolet, 13 families gave 154 
purple mottled, 159 black, 39 yellow mottled, 59 yellow 
(or brown), 160 white, and 12 unclassified. In the cross 
between Prolific Black Wax and White Flageolet, 3 
families gave 53 purple mottled, 59 black, 44 white and 
4 unclassified. 

On comparing these results with those published by 
Tschermak'! it is found that they are in perfect accord- 
ance with them, as he also found in a number of similar 
crosses, an equality between the mottled and self-colored 
beans. But our conclusions were diverse as to the 
source of the mottled pattern, I assuming that the mottled 
factor was brought into the combination by the white 


*Tschermak, E. Weitere Kreuzungsstudien an Erbsen, Levkojen und 
Bohnen. Zeitschr. Landw. Versuchsw., 7, pp. 533-638, 1904. 


No. 499 | A NEW MENDELIAN RATIO 435 


bean as a simple Mendelian unit, while he assumed that 
a mottled factor was carried as a ‘‘eryptomere’’ by the 
pigmented bean and that the white bean acts simply as 
a releasing agent or activator which allows or compels 
the latent mottling to become apparent. 

The ratio 18:18:6:6:16 must have at first a very un- 
familiar look to the student of genetics. It was not ex- 
plained by Tschermak, but was separated by him into two 
groups of 9:3:4, wherein the interrelations of the several 
terms need no explanation. 

The census of my second generation was completed 
shortly after the appearance of De Vries’s? interesting 
account of ‘‘Twin hybrids” in Œnothera, and the sug- 
gestion lay at hand that this ratio presented by Phaseolus 
might be a case of twin di-hybrids, the first and second 
terms of the ratio, as also the third and fourth terms, 
being in each ease different phases or aspects of a single 
unit, which might be expressed thus 9A:9V :3B:3a :8W. 

While such an hypothesis would fit the conditions pre- 
sented by the F,, it was seen very soon that it does not 
harmonize with the occurrence of a uniformly purple 
mottled F,, nor with the splitting phenomena of F,, a 
portion of which has been already examined. A consid- 
eration of the F, and F, shows that there are three dis- 
tinct units involved, as was stated in my earlier papers, 
namely —a pigment factor, P, a blackener, B, and a mot- 
tled pattern, M. 

If all of these characters behaved according to the 
simple Mendelian method, the ratio would be that pre- 
viously predicted, and out of every 64 individuals, on an 
average, 27 would have purple mottled seeds, and 9 black. 
In order that the number of individuals having purple 
mottled seeds shall be equal to the number having black 
seeds, it is necessary that of the 27 that should on theo- 
retical grounds be purple mottled, 9 must show no purple 
mottling but must be black, though it contains the domi- 
nant mottle factor, M. This group of 27 purple mottled 

2 De Vries, H. On Twin Hybrids. Bot. Gaz., 44, pp. 401-407, D 1907. 


436 THE AMERICAN NATURALIST [Vou. XLII 


individuals belonging to the theoretical F, ratio consists 
of the following eight types: 


1 PBMPBM 
PBMPBm 
PBMPbM 
2 PBMpBM 
4 PBMPbm 
4 PBMpBm 
4 PBMpbM 
8 PBMpbm 
a 


There is only one basis on which a group of 9 indi- 
viduals having a common gametic feature may be de- 
rived from this group, namely, on the ground of homo- 
zygosis with respect to any single allelomorph. ‘Thus, 
there are 9 homozygotes with respect to P (1 PBMPBM 
+2 PBMPBm +2 PBMPbM +4 PBMPbm), 9 homo- 
zygotes with respect to B (1 PBMPBM + 2 PBMPBm + 
2 PBMpBM + 4 PBMpBm), and 9 homozygotes with re- 
spect to M (1 PBMPBM + 2 PBMPbM +2 PBMpBM 
+4 PBMpbM), and the assumption that any one of these 
groups will give self-colored beans will answer the re- 
quirements of the empirical F, ratio, 18:18:6:6:16. 

The only way in which it is possible to decide which 
of these three possible groups of 9 homozygotes is respon- 
sible for the equality of the mottled and self-colored 
types is to test their applicability to the other genera- 
tions, since they all fit equally well the ratio found in the 
second generation. If homozygotes with respect to P 
hide the presence of M, it will be impossible to find an 
individual with mottled seeds which will not give a 
progeny, one fourth of which will be white-seeded ; but of 
the F families already examined, a number have been 
found which, while continuing to give mottled and self- 
colored beans in the ratio 1:1, have failed to produce any 
whites. If the homozygotes with respect to B are re- 
sponsible for the latency of M, some brown or brown 


bo bo 


No. 499] A NEW MENDELIAN RATIO 437 


mottled offspring would be produced by every purple- 
mottled parent, and there would be no equality between 
the purple-mottled and black in many families of the 
third and subsequent generations; but those F, families 
which have been thus far investigated show a number 
of instances in which purple mottled parents produce 
no brown or brown mottled young and there is a con- 
tinued equality between the mottled and self-colored 
offspring of such parents. The remaining possi- 
bility, namely, that individuals which carry the mottled 
pattern, M, but are homozygous with respect to that char- 
acter, are not mottled but self-colored, is the only one that 
fits all of the observed facts. The mottled color-pattern 
must be heterozygous in order to become apparent in the 
hybrids. 

We may then indicate the composition of the group of 
individuals of F, which carry the dominant mottling fac- 
tor, M, and the expectation as to the composition of the 
offspring which each will produce in F, as follows: 


1 PBMPBM = B1 (Bl) (M latent in all). 

2 PBMPBm == PM(1PM:1B1) ( latent in 4 the Bl). 

2 PBMPbM = BI1(3B1:1Br) (M latent in all). 

2 PBMpBM —BI1(3B1:1W) (M latent in all). 

4 PBMPbm —PM(38PM:3Bl:1BrM:1Br) (M latent 
in 4 the self-colored). 

4 PBMpBm = PM (3PM:3B1:2W) (M latent in 4 the 
Bl and 3? the W). 

4 PBMpbM —BI(9BI:3Br:4W) (M latent in all). 

8 PBMpbm =—=PM(9PM:9BI:3BrM:3Br:8W) (M la- 
tent in 4 the self-colored and ł the 


W): 


It will be seen from this scheme that the mottled color- 
pattern could exist and does exist as a latent (i. e., in- 
visible) character in pigmented beans just as well as in 
the white bean, which is contrary to the assumption made, 
when I insisted that the mottled pattern must have come 
from the white bean. It is also obvious that the mottled 


438 THE AMERICAN NATURALIST [ Vou. XLII 


pattern could not exist in both the pigmented and white 
beans used in these crosses, as in that case the F, hybrids 
would have been homozygous with respect to this char- 
acter and would have been black self-colored instead of 
purple mottled. In attempting to settle the question as to 
the origin of this mottled color-pattern I have carefully 
examined the results recorded by Tschermak and find evi- 
dence that at least one pure-bred pigmented bean must 
possess the mottled pattern while another does not. 
Whether the white beans used by him carried latent M 
can not be settled at present, but it is now plain that he 
may have been right in referring the mottling factor to 
the pigmented beans. My White Flageolet as well as all 
the white beans used by Tschermak may not have the 
mottled pattern, and the gametic formula of the White 
Flageolet should then be written pBm, instead of pBM. 

This question can only be settled by further careful 
crossing. The evidence derived from Tschermak is as 
follows: In the cross between ‘‘Hundert fiir eine” (light 
yellowish brown) and ‘‘ Mettes Schlachtschwert’’ (white) 
there was no mottling in the offspring; ‘‘Hundert fiir 
eine’’ crossed with ‘‘Schwarze Neger’’ (black), both self- 
colored, gave mottled offspring. Now according to my 
hypothesis, if ‘‘Schwarze Neger” carries the mottled 
pattern, ‘‘ Hundert fiir eine’’ does not have it, and in turn, 
‘*Mettes Schlachtschwert’’?’ must not have it. If 
‘‘ Schwarze Neger,’’ on the other hand, does not carry the 
mottled pattern, ‘‘Hundert fiir eine’’ has it, and in this 
case ‘‘ Mettes Schlachtschwert’’ must also carry it. We 
can not say certainly, therefore, that the white ‘‘ Mettes 
Schlachtschwert’’ does or does not have the mottled pat- 
tern, but on theoretical grounds either condition would be 
equally possible. 

Among the corollaries of the eevianeien here given for 
the ratio 18:18:6:6:16 is not only the fact already given 
that the mottled pattern may be carried by the pigmented 
bean invisibly quite as well as by the white bean, but 
also, since the mottled beans are heterozygous with re- 


No. 499] A NEW MENDELIAN RATIO 439 


spect to M, it would be impossible to have any of them 
breed true, i. e., the mottled bean is in the same category 
in this respect as the famous Blue Andalusian fowl. This 
conclusion is supported by 48 families of the third and 
fourth generations reported by Tschermak and by over 
sixty families of the F, from my own mottled hybrids 
which have been already examined. Not one instance 
has been found in which the offspring of a mottled hybrid 
were even approximately all mottled. 

The existence of pure-bred mottled races raises the in- 
teresting question as to what relation exists between these 
mottled hybrids which are heterozygous and can not 
breed true and the true-breeding mottled varieties. 
Tschermak*® shows that in crosses between constant 
mottled races and self-colored races, the mottled pattern 
acts as a typical Mendelian dominant, the hybrids split- 
ting in F, and subsequent generations in the ratio, 3 
mottled :1 self-colored. 


LATENCY DUE TO SEPARATION 

With respect to the question of latency since the 
purple mottling may not be a latent character of the 
White Flageolet, the type of latency discussed in my 
previous papers was only certainly exemplified by the 
pigment-changer, B, carried by the white bean. This 
type of latency is discovered by the production of a 
novelty when two allelomorphs are brought together, one 
or each of which, when acting alone, produces no visible 
character. Thus the black or purple color of these 
hybrids is due to the combination of the yellow or brown 
pigment of the pigmented parent and the colorless pig- 
ment-changer borne by the white parent. It may be called 
latency due to separation since patency is brought about 
by recombination. In my first paper on latency,* issue 

5 Loe. cit. 

‘Shull, G. H. Some Latent Characters of a White Bean. Science, 
N. S., 25, pp. 828-832, May 24, 1907. 


440 THE AMERICAN NATURALIST [ Vou. XLII 


was taken with Lock® regarding his assumption that 
novelties which appeared in crosses between certain peas 
were due to inactive units which became active on cross- 
ing. Lock has since reconsidered that case and inde- 
pendently come to the same conclusion that I reached, 
namely, that the spotted seed-coat was introduced by the 
white-coated pea in which it was invisible owing to its 
separation from the pigment-producing factor. This is 
not an uncommon type of latency and seems to be the 
only type included by writers who have treated the sub- 
ject of latency from the Mendelian view-point. It gives 
rise to such modifications of the Mendelian ratios as 9:3:4, 
9:7, 27:9:9:3:16, 27:9:28, etc., instead of the theo- 
retical 9:3:3:1 and 27:9:9:9:3:3:3:1. Some of these 
modified ratios are of more common occurrence, and are 
more familiar, than the unmodified ones, perhaps owing 
to the fact that albinism has been so frequently involved 
in the Mendelian investigations. Characteristics which 
are rendered latent by separation in the course of Men- 
delian hybridization have been called ‘‘masked’’ char- 
acters by Punnett." This is not a particularly apt term 
for latent characters of this type, and would be much 
more appropriately applied to cases of latency due to 
hypostasis discussed below. 


LATENCY DUE TO COMBINATION 

The existence of mottling as a latent characteristic in 
pigmented beans, due to the fact that it only becomes ap- 
parent when in the heterozygous condition, is obviously 
of an entirely different type. Instead of being a phe- 
nomenon of separation, it is due to the union in the 
same zygote, of two dominant allelomorphs, either of 
which alone will produce a manifest character, but 

° Lock, R. H. Studies in Plant Breeding in the Tropics. Ann. Roy. Bot. 
Gard. Peradeniya, 2, pp. 299-356, 1904. See p. 241. 

Lock, R. H. On the Inheritance of Certain Invisible Characters in 
Peas. Proc. Roy. Soc., B, 79, pp. 28-34, 1907. 


* Punnett, R. C. Mendelism, 2d ed., pp. viii + 85, 1907, London: Mac- 
millan & Co. See pp. 47-53. 


No. 499] A NEW MENDELIAN RATIO 441 


which, when acting together, produce none. This may 
therefore be called latency due to combination, since 
patency is brought about by separating the two allelo- 
morphs whose union effaces their characteristic mani- 
festation. If the White Flageolet carries the mottling 
factor, M, as was at first supposed, the appearance of 
mottling as a novelty in the first generation hybrids was 
due not alone to that fact, but just as much to the fact 
that the pigmented bean does not carry the mottled 
factor; or if, on the other hand, it should prove true on 
further investigation that the white bean does not carry 
the mottled factor, the mottled F, is due to this very fact, 
quite as much as to the fact that the colored bean does 
possess it. 

The conclusion, reached in my previous papers, that the 
primitive bean was probably purple mottled and that 
the purple mottled condition is therefore an atavistic 
one, seems to be left in some doubt, because of the ex- 
istence of two types of mottling, one of which behaves 
as a typical Mendelian unit as shown by Tschermak, the 
other having the peculiar faculty of losing its external 
manifestation the instant it becomes homozygous. I 
have no doubt that in some form the mottling unit is a 
primitive one, but whether the ancestral bean possessing 
that unit was mottled or self-colored would depend en- 
tirely on which type of the mottling unit it carried. In 
order to breed true it is necessary that both eggs and 
sperms shall all carry the mottled factor, and if this 
mottled factor were of the latter type, the beans pro- 
duced by the union of such sperms and eggs, being 
homozygous with respect to mottle, would be self-colored, 
while if the mottle was of the former type, the homozy- 
gous beans would be mottled. The conclusion as to the — 
allelomorphic composition of the original bean is prob- 
ably correct, but as to its external appearance, it may as 
well have been black as mottled. 

The peculiar behavior of the purple mottled allelomorph 
in my hybrids and in most of Tschermak’s, may havea 


442 THE AMERICAN NATURALIST [ Vou. XLII 


very important bearing upon the interpretation of what 
are known as mid-races, 7. e., races which regularly pro- 
duce two forms in about equal proportions, for, as has 
been seen, the mottled beans of all the hybrid families 
which did not have a mottled bean as one of its original 
pure-bred ancestors, constitutes a mid-race. This fact 
was recognized by Tschermak (loc. cit., p. 47), though he 
attributed it to an unexplained effect of cross-fertiliza- 
tion, and not to the characteristic behavior of a definite 
Mendelian allelomorph. Other mid-races may likewise 
represent instances of latency due to combination. Wher- 
ever there is a double series of characters occurring in 
about equal numbers in the progeny of a self-fertilized 
individual, this type of latency should be looked for. 
Purple punctation and brown flecking, which occur as 
novelties in the seed-coats of hybrid peas, were found by 
Tschermak to behave in a manner quite analogous to the 
mottling in beans, the first generation showing dominance 
of the novelty and subsequent generations always split- 
ting into the punctate and non-punctate or the flecked and 
unflecked, respectively, and these no doubt are also cases 
of latency due to combination. Lock’ has shown, on the 
other hand, that when certain mottled and spotted peas 
are crossed with self-colored peas, the mottling and spot- 
ting act as typical Mendelian dominants capable of ex- 
traction as characteristics of pure-breeding races, which 
ought to be expected, since the homozygous parental 
strains possessed these characters. The apparent dis- 
crepancy between his results and those of Tschermak will 
be fully explained if we assume that there are two types 
of these color-pattern characters in peas, as there are in 


ans. 

In all of these cases of latency due to combination, the 
two units involved are of the same kind, so that the 
latency oceurs only in the homozygous individuals, thus 
resulting in a striking contrast between homozygotes and 


‘Lock, R. H. On the Inheritance of Certain Invisible Characters in 
Peas. Proc. Roy. Soc., B, 79, pp. 28-34, 1907. 


No. 499] © A NEW MENDELIAN RATIO 443 


heterozygotes. There are many other cases in which the 
homozygote and heterozygote show marked and often un- 
expected differences, the case of the Blue Andalusian fowl 
being one of the best known of these, but the heterozygous 
type of the Blue Andalusian fowl or other similar forms 
is not a case of latency at all, since no hidden allelomorph 
is brought to light as a result of heterozygosis, but only an 
unexpected external manifestation. 


LATENCY DUE To Hypostasis 

A third type of latency has also appeared in these bean 
hybrids, as best exemplified by a cross between the Prolific 
Black Wax and the Ne Plus Ultra, and between Prolific 
Black Wax and Long Yellow Six Weeks. In both of these 
crosses, besides the black and orange or black and yellow 
which were expected in the ratio 3:1, there have appeared 
a considerable number of beans of a dark seal brown or 
a dark greenish brown color. It is certain that these 
dark brown beans owe their color to the latency of a dark 
brown factor in the black bean. It has not been an in- 
frequent occurrence to find black beans, not quite perfectly 
matured or which have been more or less weathered, that 
show this brown color apparently underlying the black. 
In this case the appearance of the novelty is due to the 
presence of a characteristic which can not be seen (i. e., 
which is latent), for the simple reason that the black pig- 
ment possessed by the same bean is so intense as to 
cover over and hide the brown pigment. The independ- 
ence of the brown and black pigments allows them to be 
separated into different individuals upon crossing the 
black with some other color. 

Letting D represent this dark brown factor, the gametic 
formula for the black bean is BD, and for the orange 
brown and yellow beans, bd. This assumption leads to 
= another rather unfamiliar modification of the Mendelian 
ratio, since the F, should consist of black, brown and 
orange or yellow in the ratio 12:3:1. The actual ratios 
are in essential accord with this expectation though there 


444 THE AMERICAN NATURALIST (Vou. XLII 


are rather wide discrepancies due to the fact that the 
categories were not as carefully distinguished at first as 
they should have’been. Thus in the case of the cross of 
Prolific Black Wax (black) with Ne Plus Ultra (dark 
orange or ‘‘brown’’) many of the dark brown beans were 
recorded at first simply as ‘‘brown,’’ and the ratio found, 
174 black:47 seal-brown:26 ‘‘brown,’’ shows clear evi- 
dence of the extent of error thus produced. A deficiency 
of black is also apparent and is no doubt due to the re- 
cording of some weathered blacks, as dark brown. In 
the cross between Prolific Black Wax and Long Yellow 
Six Weeks, the deficiency in the blacks and corresponding 
excess in the dark brown is even more striking, giving the 
ratio, 155 black:55 dark brown:9 yellow:5 unclassified, 
theory requiring 168 black:42 dark brown:14 yellow. 
This factor D is also found to be present in the White 
Flageolet, where, like the black factor, B, it is latent by 
separation. 

The occurrence of dark brown as an invisible character 
in the black bean may be called a case of latency due to 
hypostasis, following the terminology suggested by 
Bateson.® The unexpected character is not inactive, but 
its characteristic manifestation is invisible because it is 
hidden or inhibited by some other quality, and can only 
become visible when the overlying or inhibiting quality is 
removed by some means. 

This type of latency is no doubt very common, as it is 
involved in many cases of simple dominance, as that 
term is generally understood. If the ‘‘presence and ab- 
sence’’ hypothesis has general validity (and there is a 
very great preponderance of evidence in favor of it), the 
term ‘‘dominance’’ should be limited to the relation of 
the presence of any characteristic to the absence of that 
same characteristic, and should not be used for the rela- 
tion between two different positive allelomorphs by virtue 
of which one hides the presence of the other. Bateson 


°” Bateson, W. Facts Limiting the Theory of Heredity. Science, N. S. 
26, pp. 649-660, November 15, 1907. 


No. 499] A NEW MENDELIAN RATIO 445 


applies the terms ‘‘epistatic’’ and ‘‘hypostatiec’’ to the 
relative capacity of one unit to hide or to be hidden by 
another, owing to what I call latency due to hypostasis. 
As a simple illustration, a cross between a pea with 
yellow cotyledons, Y, and one having green cotyledons, 
G, shows Y dominant over its absence, y, and not over G. 
This would become immediately obvious if we could cross 
the yellow pea with still another type, say with one hav- 
ing colorless cotyledons. The correct gametic formula 
for the yellow pea is not Y but YG, in which the green is 
latent owing to the fact that Y is epistatic to G. The 
gametic formula of the green pea is yG. 

That this is a correct interpretation of the apparent 
dominancy of one positive allelomorph over another is 
shown by some of my bean crosses. Thus Ne Plus Ultra 
(dark orange yellow) crossed with Long Yellow Six 
Weeks (light yellow) produced in 14 F, families, 382 
orange yellow:130 light yellow, an apparent dominance 
of orange over light yellow. That the light yellow is 
latent in Ne Plus Ultra and is not the recessive condition 
of the orange yellow allelomorph is proved by the fact 
that in the F, families of the cross between White Flageo- 
let and Ne Plus Ultra, light yellow beans appear. Let- 
ting O represent the orange allelomorph and Y the yellow 
one, the gametic formula of Ne Plus Ultra with respect 
to these two factors is OY, that of the yellow bean is oY, 
and that of the white bean likewise oY. 

The ratio, 12:3:1, presented by the crosses of Prolific 
Black Wax with Ne Plus Ultra and Long Yellow Six 
Weeks, has been reported for but one other case so far 
as I know, though it ought not to prove very uncommon. 
It will appear in the F, of any cross which produces an 
F, of the form ABCab with B hypostatie to A, C hypos- 
tatic to both A and B, and neither A, B, nor C latent from 
any other cause. In these beans the crosses are of the 
type ABC X abC = ABCab, i. e., both B and C are latent 
in the one parent and no latent characters are demon- 
strated in the other. The same ratio will result from a 


446 THE AMERICAN NATURALIST [ Vou. XLII 


cross of the type AbC X aBC =— ABCab provided the 
same relations exist among the several allelomorphs as 
before. In this case the character C is latent by hypo- 
stasis in both parents. This condition has been realized 
by Toyama’? in hybrids between the common Japanese 
white silk-worm and the Siamese striped silk-worm in 
both of which a ‘‘pale,’? unmarked type is latent by 
hypostasis. The F, is uniformly striped like the 
Siamese, and the F, consists of striped, ‘‘white,’’? and 
‘“pale’’ in the ratio 12:3:1. Toyama’s statement that the 
‘‘pale’’ character was in the ‘‘dormant’’ state indicates 
a misconception of the nature of latency due to hypostasis. 


LATENCY DUE to FLUCTUATION 


Another very potent cause of latency is to be found in 
fluctuation. It is well known that many of the less 
marked qualities of plants do not appear under unfavor- 
able conditions of growth. By growing the offspring of 
these poorly developed individuals under favorable condi- 
tions they may be shown to possess all the characters of 
_ other members of the race to which they belong. In- 
visibility produced by this cause may be called latency 
due to fluctuation. Patency is brought about by good 
feeding, room for full individual expression, ete. As a 
specific example, I may mention my experience with 
several biotypes of Bursa bursa-pastoris (L.) Britton. 
These differ from one another by certain characteristic 
lobings of the leaves, and these characters have proved, 
on crossing, to be typical Mendelian unit-characters. 
However, by growing the plants belonging to any of the 
several biotypes under sufficiently unfavorable conditions 
they may be made to produce seeds while bearing only 
the unlobed juvenile type of leaf. The Mendelian rosette 
characters are then wholly invisible or latent. If the 

” Toyama, K. Studies on the Hybridology of Insects. I. On some silk- ` 
worm crosses with special reference to Mendel’s Law of Heredity. Bull. 


Coll. Agr. Tokyo Imp. Univ., 7, pp. 259-393, pls. VI-XI, July, 1906. See 
pp. 348-353 and pl. X, III, a, b, and e. 


No. 499] A NEW MENDELIAN RATIO 447 


offspring of such plants are grown under favorable con- 
ditions the latent characters are again rendered patent, 
showing that the loss of external manifestation has had 
no influence upon the allelomorphs themselves; they were 
present in the badly developed specimens, but were in- 
visible because a sufficiently late stage of differentiation 
was not attained to permit them to express themselves. 
Another striking case in which the latency of a Men- 
delian character, perhaps due to fluctuation, has been 
fully demonstrated, is in the cross between blue and 
white Indian corn investigated by Lock.1! The blue is, 
in general, dominant over the white, but the white grains 
are always in excess of expectation, sometimes more, 
sometimes less; subsequent breeding tests with the whites 
show that a sufficient proportion of them are heterozy- 
gous, instead of extracted recessives, to make up the 
deficiency found in the number of blues in the preceding 
generation. It is not impossible, as Lock suggests, that 
further investigation of this case will discover some 
other cause than fluctuation for the latency of the blue 
aleurone layer in these white-grained heterozygotes. 
The classic case of so-called ‘‘double adaptation’’ in 
Polygonum amphibium which is pubescent in its terres- 
trial form and glabrous when grown as an aquatic, and 
other cases of the same kind, present illustrations of 
latency due to fluctuation, instead of being due to the 
presence of two antagonistic determinants whose activ- 
ities are mutually exclusive as suggested by De Vries.!? 
The very common occurrence of latency due to fluctua- 
tion must have an important bearing upon the signifi- 
cance of cultural conditions for the production of varia- 
tions. There has been much diversity of opinion on this 
point, the general impression being that cultivation and 
the removal of competition are very potent in inducing 
"De Vries, H. Species and Varieties, their origin by mutation, pp. 
xviii + 847. 1905. Chicago: Open Court Pub. Co. See p. 430 et seq. 
“Lock, R. H. Plant Breeding in the Tropics. III. Experiments with 
maize, Ann. Roy. Bot. Gard. Peradeniya, 3, pt. 2, pp. 95-184, November, 
1906. See pp. 144-163. : 


448 THE AMERICAN NATURALIST [ Vou. XLII 


variation, and that in consequence of this fact it is im- 
proper to apply principles derived under cultivation to 
plants growing free in nature. There can be no doubt 
that good cultural conditions render patent many internal 
characters which are invisible under conditions of poor 
nutrition and crowding, and this fact together with the 
fact that many of the common culture-plants are complex 
hybrids, may fully account for the general impression 
regarding the effects of culture. There is no satisfactory 
evidence that good feeding and other conditions usually 
supplied under tillage have any effect in the production 
of the mutations upon which the external characters no 
doubt ultimately depend. 


GENERAL CONSIDERATIONS 

It is obvious from the foregoing results and discussions 
that latency is not a simple phenomenon, but may be due 
to anumber of different circumstances. The point which 
I have strongly emphasized in my two preceding papers 
on the subject of latency—namely, that cases of latency 
must be explained, not upon the ground of inactivity or 
dormancy of characteristics, but simply on their invisi- 
bility— is fully borne out by all the facts here presented. 
The several different types depend upon the different 
causes for the invisibility of the characteristics. 

Of the four types of latency. here recognized, the first 
three types—those in which latency is due to definite in- 
terrelations between Mendelian units—will give rise to 
definite characteristic ratios which are as constant for 
each case as the typical ratios are for typical Mendelian 
phenomena. This is not so with latency due to fluctua- 
tion, as the variable conditions upon which the fluctua- 
tions depend may be such that any proportion of the indi- 
viduals from none to all may have the character in ques- 
tion latent. This is not only true of the characters of 
pure-bred types as exemplified by Bursa bursa-pastoris, 
but is even more apt to be true of heterozygotes, thus re- 
sulting in many deviations from the correct ratios, as 


No. 499] A NEW MENDELIAN RATIO 449 


seen in Lock’s blue X white corn cross and doubtless in 
very many other cases. 

It is probable that many discrepancies between actual 
and theoretical ratios are due to some sort of latency. 
This will generally be detected readily in subsequent gen- 
erations, and no one should be hasty in declaring that a 
character which is of the splitting kind is non-Mendelian 
until the various types of latency are considered which 
may have taken part in modifying the ratios. ‘‘ Variable 
potency,” ‘‘contamination’’ or ‘‘impurity’’ of the 
gametes, and ‘‘alternating dominance’’ will all need to 
be reconsidered and in some cases reinvestigated, before 
they can have any secure standing as exceptions, amend- 
ments or additions to the simple law of ‘‘purity of the 
gametes’’ which is the essence of Mendelism. 

There is still another way in which unexpected ratios 
may be produced, without in any way affecting the funda- 
mental principle of the purity of the gametes, their pro- 
duction in equal numbers, and their union according to the 
laws of chance, and while the question of latency is not 
involved in this case, it deserves to be mentioned in this 
connection. Baur'*® has shown that in a variegated race 
of Antirrhinum, the variegation belongs only to the hetero- 
zygote. The extracted recessives are green and the ex- 
tracted dominants fail altogether to appear, owing evi- 
dently to the fact that the zygote so formed is inca- 
pable of development, the ratio resulting from self- 
fertilization of the heterozygotes being therefore 2:1. It 
is conceivable that every degree of inefficiency of zygotes 
formed by the union of two particular allelomorphs might 
occur and thus quite various modifications of the expected 
ratios be the result, when those ratios are determined by 
a count of the successful zygotes. This cause for the 
failure of the expected ratios is certainly of rare occur- 
rence, but like questions of latency it can be demonstrated 

1 Baur, E. Untersuchungen über die Erblichkeitsverhiltnisse einer 
nur in Bastardform lebensfahigen Sippe von Antirrhinum majus. Ber. 
Deutsch. Bot. Gesell., 25, pp. 442-454, 1907. 


450 THE AMERICAN NATURALIST [ Vou. XLII 


without difficulty by breeding tests, and these should be 
made before any new principle is invoked, or the old and 
well-founded principles are declared invalid, in the at- 
tempt to account for such discrepancies. 


SUMMARY 

The foregoing discussion and conclusions may be sum- 
marized thus: 

In certain bean hybrids, mottled seed-coats depend 
upon the presence of a mottling allelomorph in a hetero- 
zygous condition, the homozygous condition giving un- 
mottled seeds. This peculiar situation results in a tri- 
polyhybrid ratio, 18:18:6:6:16, instead of the usual 
ratio, 27:9:9:3:16. 

Latency is held to mean invisibility, and not inactivity 
or dormancy, and four types are recognized, according to 
the different causes of invisibility; still other types may 
be found. The four types discussed in this paper are: 

(a) Latency due to separation, in which an allelomorph 
when acting alone has no external manifestation and is 
only rendered patent by combining it with another allelo- 
morph. Such lateney gives rise to the ratios 9:3:4, 9:7, 
27:9:9:3:16 and 27:9:28, instead of the theoretical, 
9:3:3:1 and 27:9:9:9:3:3:3:1. 

(b) Latency due to combination, in which two dominant 
allelomorphs, each giving rise to a peculiar character 
when acting alone, lose their external manifestation when 
co-existing in the same zygote. Upon self-fertilization 
this type of latency gives rise to such ratios as 1:1, 3:3:2, 
18:18:6:6:16, ete., and may be found to account for the 
existence of certain mid-races, and other cases in which a 
double series of characteristics are presented in nearly 
equal numbers. 

(c) Latency due to hypostasis, in which the presence of 
one allelomorph can not be detected owing to the presence 
of another allelomorph, the character produced by the 
latter being unmodified by the activity of the former. 
This type of latency is exemplified by the black bean 


No. 499] A NEW MENDELIAN RATIO 451 


which hides the presence of a wholly distinct brown allel- 
omorph, and a dark orange bean which carries invisibly 
a light yellow allelomorph. This condition gives rise 
in one series of crosses to the ratio, 12:3:1. Properly 
the term ‘‘dominance’’ should be limited to the relation 
between any positive characteristic and its own absence. 
Whenever one positive character seems to dominate 
another positive character, the latter is latent by hypo- 
stasis in the individual possessing the former. 

(d) Latency due to fluctuation, a very frequent phe- 
nomenon in which characteristics disappear under con- 
ditions of poor nutrition, ete. Cultivation under favor- 
able conditions makes such characteristics patent and this 
fact may account in part for the general impression that 
cultivation induces variation. Cases of ‘‘double adapta- 
tion’’ are examples of this type of latency. 

Many discrepancies between theoretical and empirical 
inheritance-ratios are due to latency, and care should be 
taken to investigate the possible latencies which may be 
present before declaring that a character is non-Men- 
delian, because of a discrepant ratio. ‘‘ Variable 
potency, ‘‘contamination’’ or ‘‘impurity’’ of the 
gametes, and ‘‘alternating dominance’’ which have been 
proposed to account for the appearance of various novel- 
ties, or of deviations from expected ratios, can have no 
secure standing until the question of latency in the sense 
of invisibility has been taken into account. 

A modification of expected ratios may rarely result 
also from the failure of certain allelomorphs to make 
vigorous zygotes when joined together in certain com- 
binations. 


THE LEG TENDONS OF INSECTS 


PROFESSOR C. W. WOODWORTH 


UNIVERSITY OF CALIFORNIA 


Ware perhaps known to working morphologists, the 
fact that the leg tendons are cuticular invaginations, and 
therefore subject to replacement at each molt, does not 
appear to have attracted the attention of any of the 
writers of text-books, and as far as the writer of this 
article is aware, has not been published at all. 

The three best developed tendons are the two operating 
the knee joint and the one that flexes the claws. These 
three are almost invariably present, though one or the 
other may be very short, or present only as a cuticular 
thickening. 

These structures are very easy to study in small insects. 
I have found aphids the most satisfactory subjects. The 
legs of most species are transparent enough to show the 
structures well when mounted whole, and the exuvie are 
especially satisfactory objects. They may also be ob- 
tained in such abundance that one can mount large series 
of specimens, thus obtaining mounts showimg the legs 
from almost any desired point of view. 

The knee joints provide for the largest amount of mo- 
tion of any of the joints of the leg, and this motion is 
all maintained in one plane by the development of two 
bearing points, making a hinge. The end of the tibia is 
small enough to telescope within the femur but for these 
articular processes. They consist of a process project- 
ing inwardly on either side of the rim of the femur, as 
shown in Fig. 1, A and B, and corresponding with these 
femoral processes there are slight outwardly projecting 
processes from the margin of the thickened rim of the 
tibia. The articular membrane at these points prevents 
the displacement of the processes. 

452 


No. 499] THE LEG TENDONS OF INSECTS 453 


The whole dorsal end of the tibia, including these 
processes, is very largely hardened and thickened and 
marked off from the body of the tibia by a deeply infolded 
ridge. Most of this thickened portion is within the end 


1. The knee joint of Aphis brassice. A, side view; B, viewed from 
beneath; T, tibia; F, femur; art.pro, articular process; e.tend, extensor tendon; 
e'e?e?, extensor muscles; f.tend, flexor tendon; f'f*f*f*, flexor muscles; art.mem, 
articular membrane. 


of the femur when the leg is fully extended, but is all 
exposed when the leg is at extreme flexion. An articular 
membrane connects the extreme edges of femur and tibia, 
as shown in Fig. 1, A. : 

Beneath, the hard parts of both femur and tibia are 
deeply emarginated, exposing a broad articular mem- 
brane. When in extreme flexion the rims of tibia and 


454 THE AMERICAN NATURALIST [Vou. XLII 


femur almost touch, and the articular membrane is drawn 
deep into the femoral cavity. The tendons find their 
attachment to the outer and inner sides of the rim of the 
tibia and, extending into the cavity of the femur, serve 
for the attachment of a series of muscles, as shown in 
Fig. 1, A and B. 

The flexor tendon in the earlier stages is only a 
V-shaped thickening of the articular membrane, but later 
the point of the V extends deeply as an internal pocket 
for the attachment of muscles reaching nearly to the base 
of the femur. There are two sets of muscles attached to 
this tendon, extending obliquely to the right and left 
sides of the femur. The first of these, ft, in the figures 
lying at about 45° to the long axis of the femur, and the 
others marked f°, f’, ete., lying more nearly longitudinally. 

The extensor tendon attaches to the dorsal rim of the 
tibia by a broad ribbon-like portion and soon expands into 
a broad plate at right angles to this first portion and then 


2. End of foot of Aphis brassicae. a, side view of claws at extreme 
extension; b, Ibid, claws flexed; c, viewed from beneath; cl, claw; t.h, tactile 
hair; fl.scl, floating sclerite; art.pro, articular process; art.mem, articular mem- 
brane; tend, tendon; m, muscle. 


narrows to a ribbon and extends deeply into the femur 
even in the earliest stages. A short muscle, e, is attached 
to the disk, followed by a series of others, somewhat as 
the flexor muscles are arranged, only that there is but a 
single series, finding their attachment to the middle 
dorsal side of the femur. Tendons are first developed as 
somewhat tubular processes, but always collapse after the 


No. 499] THE LEG TENDONS OF INSECTS 455 


molt so that the tubular character can never be made 
out. In the case of the extensor tendon of the knee the 
enlarged disk must require a considerable stretching of 
the portion of the tendon further out to enable it to pass. 
The tendon of the claw is very short up to the last 
molt in the case of plant lice. The structure at the 
end of the last tarsal joint is shown in Fig. 2. At 
the extreme end of the foot there are two processes 
over which the base of the claws rotate. The only 
other attachment aside from the soft articular mem- 
brane is a median floating sclerite capping the larger 
part of the end of the cavity of the foot and which 
bears the tactile spines extending forward below the 
claws. This floating sclerite in other insects forms the 
base of the empodium and pulvillæ. Neither of these is 
present in the case of the plant lice unless the soft skin 
immediately beyond this sclerite be so designated. The 
lower edge of the margin of the cavity is a strongly 
developed ridge upon which the internal tendon bears 
when the claws are extended, and against which the float- 
ing sclerite rests in extreme flexion. On either side of 
this thickened and elevated ridge there is a distinct notch 
allowing considerable lateral motion of the sclerite. The 
posterior ridge of this floating sclerite extends inward 
as two processes joining with the two wings of the heart- 
shaped tendon. The tendon proper is entirely internal 
as is shown in the figure, and the muscle fibers are 
attached to all sides. The other attachment of the muscle . 
is to the base of this large second joint of the tarsus. 
There are really no true tendons in insects; 7. e., the 
tendons of the legs are only such in a physiological or 
morphological sense, and not at all in structure or origin, 
but belong instead to the class of internal processes which 
includes the well-known internal skeleton or the head and 
thorax, the tendons of the jaws in mandibulate insects, 
the great internal disk-like tendons for the attachment of 
the elevator muscles of the wings in the Odonata, and the 
skeletal and tendonal process of the ovipositor. The 


456 THE AMERICAN NATURALIST (Vou. XLII 


only difference between a skeletal process and a tendon 
is that one is invaginated from a relatively fixed part of 
the body and the other from a moving part. While in- 
sect tendons are, therefore, not homologous with the ten- 
dons of vertebrates, it is probably wise to retain the 
name just as in the case of femur and tibia for parts of 
the leg, where likewise there is no homology with the 
bones of vertebrates where the names primarily apply. 


ABNORMAL INCISORS OF MARMOTA MONAX L. 


CHARLES A. SHULL 


TRANSYLVANIA UNIVERSITY, LEXINGTON, Ky. 


THE common woodchuck or ground hog, Marmota 
monax, is found rather frequently in most parts of cen- 
tral Kentucky; and, since it occupies the same burrows, 
or others in the immediate vicinity, generation after gen- 
eration, it is not uncommon to find in these regions por- 
tions of their skeletons, skulls, vertebra, teeth, ete., in the 
neighborhood of their habitations. 


Fig. 1. Skull of Marmota monaz L., right incisor removed. Natural size. 
Photograph by Soci. Lexington, Ky 

The interesting specimen which is illustrated here was 
found near Silver Creek, Madison Co., Ky., by Mr. 
Charles Meeks, who presented it to Mr. Thomas Goff, of 
Lexington, Ky. It has recently been given to the Mu- 
seum of Transylvania University. The upper incisors 
are extremely long and curved so as to form with the 
parts imbedded in the premaxilla more than a complete 

457 


458 THE AMERICAN NATURALIST [ Vou. XLII 


circle. This is beautifully illustrated by Fig. 1, in which 
the right incisor has been removed from the jaw. 

Both teeth are turned somewhat toward the right, so 
that the right one projects from the mouth; but the left 
incisor strikes the roof of the mouth to the right of the 
median suture, piercing the palatine plate of the maxilla 


Fig. 2. Skull of M. monas L., with left incisor piercing palatine plate of 

right maxilla. Natural size, Photograph by Spengler, Lexington, K 
(Fig. 2) and extending through it to a distance of about 
5mm. The left tooth is not as long as the right one, its 
growth having been retarded, perhaps by the hardness 
of the bone it penetrated. 

The manner in which the teeth of Marmota monax 
grow is familiar to all who know the Rodentia. The 
rodents all have a diphyodont dentition, that is, there are 
two sets of teeth, a temporary or deciduous set, and a 
permanent set. But the permanent teeth never cease to 
grow. There is a persistent pulp at the base of each 
tooth, which grows throughout the life of the individual. 

Ordinarily the corresponding teeth of the upper and 
lower jaw oppose each other perfectly, and the growth 
from the pulp only compensates for the amount worn off 
by biting. The incisors have a heavier coat of enamel on 


No. 499] INCISORS OF MARMOTA MONAX L. 459 


the anterior portion of the tooth, and the more rapid 
wearing of the posterior edge keeps these front teeth 
chisel-like and sharp. 

The abnormal growth of the incisors will occur when- 
ever the upper and lower teeth fail to meet. An injury 
to either jaw, as for instance a bullet wound, might de- 
stroy the perfect opposition of the incisors. But the 
teeth in this specimen are sharp pointed and not worn 
at the distal end, as they would be if they had ever func- 
tioned properly, which fact would indicate that the wound 
must have occurred before the permanent teeth appeared. 

A careful examination shows that the abnormality can 
be accounted for in another way. ‘The socket of the left 
incisor is not normal in its position, and the tooth itself 
grows inward toward the right incisor, striking it about 
8 mm. from the jaw. The latter tooth has on its inner 
side a groove extending from near the distal end to the 
point where the two incisors are in contact. This groove 
was produced by the pressure of the left incisor upon 
the right, and this pressure is undoubtedly the cause of 
the failure of both teeth to meet the lower ones. The 
abnormal growth then depended primarily upon a con- 
genital abnormality in the position and direction of the 
socket of the left incisor. One of the lower teeth of the 
same skull was found, but has been misplaced. Mr. Goff 
informs me that it also was curved and much longer than 
usual. 

It would be of interest to know how the animal with 
this curious set of teeth obtained food sufficient to prevent 
starvation. It may well be that this abnormality was 
the chief determining factor in its struggle for existence. 


A NOTE ON THE COLORATION OF PLETHODON 
CINEREUS 


HUGH DANIEL REED 
CORNELL UNIVERSITY 


On September 9, 1905, Mr. A. A. Allen found, near 
Buffalo, N. Y., a salamander! 6.5 em. long which was, at 
first sight, believed to be a small Spelerpes ruber, but 
closer inspection proved it to be otherwise. The head, 
sides and back are of uniform coral red, gradually fading 
into pinkish on the immaculate belly (Fig. 7). The 
sides and the dorsum of the distal half of the tail are 
heavily mottled with black, leaving the dorsal line of the 
proximal half the same color as the body. The mottling 
extends upon the ventral side of the tail, but the spots are 
here much lighter so that the general pink color of the 
under parts is evident. On the right side the black 
blotches of the tail begin immediately behind the leg, 
while on the left the base of the tail is an immaculate red 
for some distance behind the leg. 

This specimen was found under a piece of bark in a 
dry and rather open woodland. About three weeks later 
in a nearby locality there was found a second specimen 
which upon comparison proved to agree in all essential 
respects of coloration with the first. This one escaped 
before it was killed and preserved. 

On April 27, 1907, near Beesemer, N. Y., a short dis- 
tance south of Ithaca, Mr. Allen found another speci- 
men? (Fig. 6) which is identical in form and similar in 
coloration to those taken near Buffalo. The Beesemer 
specimen is a carrot red with a cluster of minute black 
dots on the top of the head and a row of similar dots 
along the sides of the back in a position which corre- 

1 No. 5,047 Cornell University collection. 

2 No. 5,048 Cornell University collection. 


460 


No. 499] COLORATION OF PLETHODON CINEREUS 461 


sponds to the dorsal portion of the black lateral band in 
Plethodon cinereus erythronotus. This row of dots is 
broadest above the region of the arm, whence it is grad- 
ually reduced as the leg is approached. The coloration 
of the tail is similar to that of the Buffalo specimen ex- 
cepting that the black color, instead of being collected in 
blotches, is more diffuse and continuous with the same 
color in the trunk region. 

When these specimens were examined more closely 
they were found to have the body proportions and all of 
the structural features of Plethodon cinereus. 

In the Cayuga Lake Basin both Plethodon cinereus 
cinereus and P. c. erythronotus are abundant and great 
variation with regard to coloration has already been 
noted. Several hundred specimens, mostly from this 
region, were examined with a view to determining the 
extent of the variation in coloration. This resulted in 
the selection of a series of fifteen individuals, of 
practically the same size, which show a fairly complete 
transition, in regard to coloration, between the typical 
Plethodon cinereus cinereus and the red forms taken near 
Buffalo. The middle of the series is occupied by a 
typical P. c. erythronotus (Fig. 4). From this variety 
the coloration in one direction grades into P. c. cinereus 
and in the other into the red form. 

Cope? describes the variety erythronotus as follows: 

“ A broad light-reddish stripe commences at the nape of the width 
of the interorbital space, and continues to the tip of the tail, on which 
it diminishes gradually in width. The central region of the stripe 
generally exhibits a very fine mottling of brownish, scarcely obscuring 
the effect of the red ground. The mottling is sometimes equally dis- 
tributed—sometimes concentrated in some places more than others. 
The sides of the body are abruptly and continuously dark brown, but 
soon fade off below into the pepper and salt of the lower sides and 
belly. . . . The color of the red stripe varies considerably. Some- 
times it has a shade of pink—sometimes of orange or yellowish.” 

In all individuals examined from this region the red 
dorsal stripe on the tail grows narrow very rapidly. The 

3 Cope, E. D., ‘‘The Batrachia of North Ameriea,’’ Bull. 34, U. S. Nat. 
Mus., p. 135. 


462 THE AMERICAN NATURALIST [ Vou. XLII 


distal third is mottled so heavily with black that the 
stripe, as such, is lost. The large number of specimens 
examined indicates that the typical P. c. erythronotus is 
not more common here than the red intermediates. 

The transition between the variety erythronotus and 
the red form is accomplished thus: the red dorsal stripe 
first extends cephalad covering the whole top of the head 
where there is found in all intermediates a sprinkling 
of brown dots (Fig. 5). It then invades the sides 
of the head passing to the snout underneath the eyes. 
From this position it spreads in all directions, replacing 
the brown until the whole body is thoroughly suffused 
with red. In such specimens the brown color-pattern is 
evident but subdued by the red tone due to the invasion 
of this color into the whitish areas between the clusters 
of brown blotches. 

The further transition consists in the expansion of the 
red ground-color and the gradual reduction of the brown 
blotches which persist longest on the top of the head, 
along the dorsal abrupt border of the lateral band, down 
the middle of the back and on the tail. In the Beesemer 
specimen only the vestiges of the brown markings remain 
in the regions just mentioned. On the limbs the invasion 
of red proceeds from the base towards the extremity, the 
brown markings showing longest upon the hands and feet. 

In the Buffalo specimen the brown markings are every- 
where apparently obliterated excepting upon the tail, the 
snout and the region between the eyes and a cluster just 
behind and below the left eye. In the alcoholic specimen 
there are revealed, along the sides of the back in the 
shoulder region, very fine specks of brown pigment ar- 
ranged in a narrow band which can be traced to the leg 
region, although the dots are faint and much scattered 
in the caudal half, and in the living specimen did not 
show at all. 

According to Copet intermediate specimens between 


* Cope, op. cit., p. 136. 


No. 499] COLORATION OF PLETHODON CINEREUS 463 


the varieties erythronotus and cinereus are uncommon, 
for he says: 

“ Among the very great numbers of specimens which I have examined 
in the collections of the Smitlisonian Institution, The Academy of 
Natural Sciences and Essex Institute I have observed but four speci- 
mens of the red-banded variety and four of the gray which could be 
regarded as intermediate in character.” 

In the material at hand I find that the intermediate 
individuals, between the varieties just named, are fairly 
numerous; so that a series was selected which forms 
almost an insensible transition from the one to the 
other. The method here is exactly the reverse of that 
described above in connection with the red forms; i. e., the 
red is replaced by brown. In describing the intermediate 
specimens which he studied, Cope outlined the method 
which I find carried out in detail in my material. He 
writes: 

“This [the intermediate character of his specimens] appears in a 
rufous cast in the dorsal color of the latter [variety cinereus] and a 
slight obliteration of the borders of the dorsal band in the former 
[variety erythronotus].” 

The brown of the lateral band in P. c. erythronotus be- 
gins first to encroach upon the red of the dorsal stripe 
so that its edges become scalloped (Fig. 3). This 
spreading of the brown color continues until the dorsal 
stripe is heavily blotched and the red becomes very dull 
(Fig. 2). Then the brown blotches gradually coalesce, 
in consequence of which the red stripe, as such, is 
obliterated, yet enough of the red pigment remains to 
give the effect of a dull liver-brown to the back of P. c. 
cinereus. In a number of specimens of this variety all 
traces of liver-brown have disappeared, rendering the 
back uniform in coloration with that of the sides (Fig. 1). 

In respect to structural characteristics no variations 
were detected except in the case of one red intermediate 
where only seventeen costal grooves were present. The 
body proportions of this individual were slightly less 
than the others. 


464 THE AMERICAN NATURALIST [ Vou. XLII 


Data bearing upon the relation of this variation to 
environment, food, moisture, etc., are entirely wanting. 
The red specimen taken near Buffalo was at an altitude 
of 1,000 feet above sea level. That near Beesemer, 800 
feet. Individuals kept in the terrarium under entirely 
different conditions than those from which they were 
taken in nature never change in coloration so far as I can 
determine, which indicates that the variation is inde- 
pendent of the nervous system. The age of the indi- 
vidual seems to have no relation to variation. Among 
adults of all sizes the different intermediate forms are 
ound. There are in the collection of Cornell University 
about a dozen specimens taken soon after transformation. 
They are all typically of either the variety cinereus or 
erythronotus except one which varies decidedly towards 
the red form. 


EXPLANATION OF PLATE. 


Fic. 1. Plethodon cinereus cinereus in which all traces of the dorsal stripe 
have disappeared. 
4. Plethodon cinereus erythronotus. 
-“ 6. The red specimen taken near Beesemer, N. Y. 
7. The red specimen taken near Buffalo, N. Y. 
The other figures, according to their position, are intermediates between 
P. c, cinereus, P. c. erythronotus and the red Buffalo specimen 


LEN ETERS REPEC 


Sine Reon Tee 
ae PERENS Dale echo AN Ma Veep, 


Ch Pry ee AA A Woe bara 


ara 


ma LEUAN eo eon 
TI e nepivaen VAE 


A.G. Hammar, del 


SOME EXPERIMENTS ON THE ORDER OF SUC- 
CESSION OF THE SOMITES IN THE CHICK 


PROFESSOR MARIAN E. HUBBARD 


WELLESLEY COLLEGE 


THE experiments described in the present paper were 
performed at the University of Chicago during the year 
1903-04, under the direction of Professor F. R. Lillie, 
to whom thanks are due for much advice and suggestion. 
In the course of the preparation of the data for publica- 
tion during the last summer I learned that another in- 
vestigator, Mr. J. Thos. Patterson (’07), had hit upon the 
same problem, and his results appeared before this 
article could be published. It has been suggested, how- 
ever, that the work described may be of value in confirm- 
ing Mr. Patterson’s conclusions. 

The problem, suggested by Professor Lillie, was the 
investigation of the statement, so generally made by 
embryologists, that, in the shiek, somites arise in front 
of the one which is formed first. An examination of the 
most important of these statements will make clearer the 
nature of the problem. The estimates of von Baer (’28) 
and His (’68) did not require serious consideration, for 
they were not based upon a close study of this point. 
That of Kupffer and Benecke (’79), who thought that 
three or four somites arose in front of the one which first 
appeared, was founded upon an examination of a rather 
wide series of embryos, but only in surface view. Miss 
Platt’s (’89) work rested upon a study of sagittal sec- 
tions, and as it was altogether a careful examination of 
the subject, my attention was directed particularly to her 
conclusions. Briefly, her account of the formation of 
the somites is as follows: The first cleft divides two 

* Loe. cit., pp. 177, 178. 

466 


No. 499] SUCCESSION OF SOMITES IN CHICK 467 


forming somites. The somite behind the cleft is called 
the first one in the series. The one anterior to it, proto- 
vertebra a, forms slowly, while four or five are making 
their appearance behind. After five or six somites are 
visible in all, another, protovertebra b, arises slowly in 
front of a. Protovertebra b is said to be rudimentary, 
never becoming completely cut off from the mesoderm in 
front. 

It will be noted in this account that although two 
somites are described as arising in front of the one first 
formed, in reality there is but one to be considered— 
protovertebra b—for protovertebra a makes its appear- 
ance at the same time with the one behind it. An ex- 
amination of Miss Platt’s sections? would lead one to 
agree in the main with her account of the order of forma- 
tion of the somites, except in regard to the appearance 
of protovertebra b, whose growth has to be followed in 
a series of sections from different embryos at succes- 
sively older stages. The difficulty of identifying a grow- 
ing somite in this way casts much doubt upon even its 
existence, and it was to test the question therefore that 
these experiments were devised. 

The aim of the experiments was to mark or destroy, 
in embryos with a small number of somites (not more 
than five or six) the most anterior somite on one side, 
and so to determine whether any more were later formed 
in front of this. The ideal stage to have secured would 
have been that of an embryo with only a single pair of 
somites, but repeated failures to obtain this condition 
verified the statement made by Miss Platt,’ founded upon 
a study of sections, that the first cleft occurs between 
two forming somites. An operation, then, even as early 
as at the time of the first cleft would have had to take 
into account the first two pairs of protovertebre. 

The methods employed in the experiments were in gen- 
eral similar to those used by Mr. Patterson. For open- 

Loc. cit., Plate I. 

t Loc cit., p. 177. 


468 THE AMERICAN NATURALIST [ Vou. XLII 


ing and sealing the egg Miss Peebles’* method was fol- 
lowed. For destroying the somites two fine depilatory 
needles, ground to a hair point on an oil-stone, were used, 
one, at the negative electrode, touching the albumen, the 
other, at the positive electrode, serving to prick the 
somite which was to be marked or destroyed. For the 
current four Samson dry-battery cells, each with an 
electromotive force of 1.5 volts, were connected in series. 
To prevent infection the instruments were sterilized in 
a flame. With this method of disinfection, 15 out of 84 
embryos, or 18 per cent., were lost, but as the loss was 
oceasioned by the sticking of the blastoderm to the shell, 
it can not be stated that it was not due in part to causes 
other than bacterial infection. A Zeiss dissecting stand 
was used for the operations, with lenses magnifying six 
diameters, and whenever possible the work was done with 
the bright sunlight shining in upon the blastoderm. So 
great is the variation in distinctness of embryos at this 
early age, that even with the best of light the somites 
could not, except in a comparatively small number of 

cases, be counted with certainty. In the 


embryos, however, which were distinct, 

there was no room for doubt as to their 
\ L exact condition at the time of the opera- 
d &--..... tion. 


From several experiments, the results 
of which furnish evidence for the solution 
of the problem, the following case has 
been selected for description: 

Sheth natant tn, Number 50 was operated upon after 30 
of operation. c= hours of incubation. The operation was 
ee ee performed with the sun shining in upon 
the blastoderm, the embryo was distinct, and its three 
somites were readily counted. Fig. 1 is a sketch made 
at the time, showing the place of the operation, in 
which, it was noted, the needle passed obliquely inward. 
t Loe. cit., p. 406. 


No. 499] SUCCESSION OF SOMITES IN CHICK 469 


‘Fig. 2 shows the same embryo after nineteen more 
hours of incubation. The heart was beating when the 
egg was opened. The embryo was preserved in picrosul- 
phuric-acetic acid, stained in Conklin’s picro-hema- 
toxylin, and mounted in xylol balsam. The drawing was 
made with the aid of the Abbe camera. 

The first right somite is noticeably 
smaller than its fellow on the left, 
there is no break between it and the 
mesoderm in front, and only the pos- 
terior part of it shows the radial 
arrangement of cells which is char- 
acteristic of the normal somite. The 
sear of the operation shows at the 
side. A deeper examination in this 
region reveals, mediad of the scar, a 
clear area extending into the limits of 
both the first and the second somite of 
that side, indicating that the injury 
reached inward from the point of 
entrance of the needle. The second 
somite is also incomplete on its dorsal 
antero-lateral corner, as shown in the 
figure. Except for these injuries and 
the bend to the right which may have 
been caused by the operation, the 
embryo appears normal, the break in 
the neural tube at the anterior end ; 
being the result of pressure of the og 
coverglass. Fic. 2, Embryo 50, 

Whatever else this experiment sesuo rome after 
proved, it showed clearly that not operation. x20. 
more than two somites could arise in 
front of the one which is first formed. This of course 
shut out at once the hypothesis of Kupffer and Benecke, 
who assumed that three or four somites are ies 
formed in front. 

Applying Miss Platt’s description of the order of ap- 


470 THE AMERICAN NATURALIST [ Vou. XLII 


pearance of the somites to this case, it would seem that 
this embryo must have had the first of the two anterior 
somites, protovertebra a, already partly formed, at the 
time of the operation, and that there should, therefore, 
have been one more, protovertebra b, to arise in front of 
this. But no such somite appears in Fig. 2, and its ab- 
sence led to the conclusion that there is no such somite 
as protovertebra b, in other words, that but one somite is 
formed in front of the first cleft which appears. The. 
simplest explanation of Miss Platt’s error is that she 
mistook protovertebra a in sections of older embryos for 
protovertebra b. This is much more probable than that 
she could have mistaken, as Mr. Patterson suggests,” the 
most posterior transitory shallow depression in the head 
mesoderm for the first cleft. 

If it be objected that the experiment does not prove 
that one or two somites may not arise in front of the one 
first formed, it may be said that if they do arise, the rate 
of their formation, compared with the rate of formation 
of those that appear behind, is contrary to the descrip- 
tion of this process by Miss Platt,’ according to whom the 
rate of formation is much greater behind the first formed 
somite than it is in front. Either then somites are not 
formed in front, or, if they do arise, the description of 
the rate of their formation is not correct. 

In conclusion, then, this experiment, in proving that 

not more than two somites could arise in front, showed 
the inaccuracy of Kupffer and Benecke’s estimate of the 
number formed. 
. It showed further, in regard to Miss Platt’s work, 
either that her description of the time of formation of the 
somites was incorrect, or, if development proceeds ac- 
cording to her account, that no somites, except the rudi- 
mentary one, arise in front of the first cleft. 

Thus the result of the experiments, with reference to 
the condition of the problem up to the time when Mr. 


t Loc. cit., pp. 129, 132. 
* Loc. cit., p. 177. 


No. 499] SUCCESSION OF SOMITES IN CHICK 47] 


Patterson began his work upon it, was to throw the 
burden of proof on those who claimed that somites do 
arise in front of the one first formed, rather than on those 
who held that, in their formation, they obey the laws of 
progressive differentiation which govern the early de- 
velopment of birds. 


1898. 


1889. 


TEXT REFERENCES. 


Baer, Karl Ernst von. Entwickelungsgeschichte der Thier 
His, Wilhelm. Untersuchungen über die Erste Anlage aed Wirbel- 
es. 


Kapten, ag und Benecke, B. Photogramme zur Ontogonie der 
Vögel. Verh. der Kal. -Leop.-Carol.-Disch. Akad. d. Naturf., 
Bd. 41, pp. 149-196. 

gine J. Thos. The Order of Appearance of the Anterior 
So n the Chick. Biol. Bull., XIII, pp 

Peebles, Fics Some Experiments on the ce Streak of 
the Chick. Arch. f. Entw.-Mech., Bd. VII, pp. 405-429. 

Platt, ulia B. pone on the Primitive Axial Biante of the * 

ull. . Comp. Zool., Harvard, Vol. XVII, No. 4, 
pp- IAT. 


DWARF FAUNAS 


PROFESSOR HERVEY W. SHIMER 


MASSACHUSETTS INSTITUTE OF TECHNOLOGY 


Favunas in which all the individuals are uniformly so 
small as to be notable for this reason are common both 
in recent and past times. Such dwarf faunas may be 
merely an association of normally small species; or they 
may be individuals much smaller than the normal size 
for that species, prevented for some reason from attain- 
ing full size. 

The following is an attempt to summarize some of the 
principal recent and dwarf faunas with the probable 
causes producing them. It is confined to invertebrate, 
water-living faunas. The article is primarily a sum- 
mary of such literature as chanced to be seen; that very 
much of importance was overlooked is undoubtedly true, 
but it is thought that the major causes of dwarfing are 
here noted. 

The first part of the article is a discussion of the chief 
agencies of dwarfing using recent examples as illustra- 
tions; the second part considers a few fossil examples of 
dwarf faunas with their probable causes. 

The following are the chief agencies of dwarfing as 


- noted in recent and fossil faunas: 


1. A change in the normal chemical content of the 
water. 

(a) Due to a freshening of the sea water. 

(b) Due to a concentration of the salt, iron, ete. 

(c) Due to an increase in H,S and other gases. 

Presence of mud and other mechanical impurities in 
the water. 

A floating habitat. 

Variations in temperature. 

Extremes in depth of water. 

472 


bo 


No. 499] DWARF FAUNAS 473 


1. A Change in the Normal Chemical Content of the 
Water.—Any change in the environment of an animal 
which is away from that best suited to its highest 
development tends to its deterioration. If a species de- 
velops best in normal sea water, then an increase or 
decrease in the chemical content of the water should be 
detrimental to the animal, and this detriment should be 
expressed in the shell, since, as shown by Hyatt and 
others, there is the most intimate relation betwen the soft 
and the hard parts of an animal, the least injury in the 
soft parts being immediately expressed in the growing 
shell. This expression will usually take the form of a 
dwarfing in size, thinning and smoothing of the shell or 
development of bizarre form. 

The possible changes in the normal chemical content of 
the water are exceedingly numerous and all doubtless 
affect the animal to a greater or less degree. The follow- 
ing appear to be some of the more important of such 
changes which produce a dwarfing effect. 

(a) A Change due to Freshening of the Water.—That 
many forms of animals find fresh water detrimental to 
them appears to be indicated by the fact that at present 
whole groups are excluded from it, as the Echinodermata, 
Brachiopoda, Cephalopoda, Tunicata, ete. 

The many streams emptying into the Black and Caspian 
seas, make them fresher than the Atlantic Ocean. The 
faunas of these are typically marine, but practically all 
are dwarfed in size as compared with the same species 
in the Atlantic. For example, the following Black ‘Sea — 
species are considerably smaller in the Black Sea than in 
the British seas: Littorina rudis, Cerithium adversum, 
Trochus umbilicus, Murex erinaceus, Nassa reticulata, 
Cardium edule, Anomia ephippium, Venus gallina, Tellina 
tenuis, Mactra triangula, Solen ensis, Pholas candida, 
ete.! 

The common European cockles, Cardium, are large, 
thick and rough shells, and thrive best under purely 
marine conditions. The species found growing in brack- 

1 Forbes, E. Nat. Hist. of European Seas, pp. 201 and 202. 


474 THE AMERICAN NATURALIST [ Vou. XLII 


ish waters are smaller than those in normal sea water. 
Cardium edule is found in the British Isles in harbors and 
high up tidal rivers, where the water gets brackish; its 
shell is modified, invariably reduced in size, thin, and with 
less strongly marked external characters. The ten 
_ species of Cardium in the Caspian Sea are all aberrant 
forms, all related back to C. edule, small, thin and smooth, 
with lateral or central teeth or both suppressed. So like- 
wise with the cockles of the Black and Baltic Seas; in the 
latter the salinity is reduced one half by the water from 
the rivers.? The Greenland cockle lives in estuaries; it is 
no longer found in Europe but is very abundant in the 
Pliocene (Crag) of Suffolk and Norfolk, especially in the 
fluvio-marine portions. It is thin, smooth, almost edent- 
ulous, with rudiments of a single tooth in each valve in the 
young shells which finally disappear. 

Some forms, as Serobicularia and Mactra solida, have 
become thoroughly adapted to a brackish water environ- 
ment and attain their largest size there. But many, if not 
most species, which live in normal sea water and in 
brackish water are smaller in the latter, as is true of 
Cardium edule, Mya arenaria and Littorina littorea. 

(b) Change due to a Concentration of Salt, Iron, etc.— 
When a body of water has become concentrated to a point 
where precipitation of its salt takes place, as is practically 
the case in the Great Salt Lake or entirely so in the Dead 
Sea, no life can exist in it. But from the normal sea 
water to this condition there takes place progressively a 
lessening both in the number of species and in the size of 
the individuals there present. 

Many fossil dwarf faunas have been ascribed to this 
cause, as, for example, those of the Permian. 

That even a comparatively slight concentration of the 
sea water may produce a dwarfing in its fauna appears to 
be indicated by the western Mediterranean species. 
Dana gives the amount of saline matter in the Mediter- 
ranean as 3.9 per cent. as against 3.6 per cent. for the 

*Dana. Manual of Geology, p. 121. . 

* Forbes, E- Loc. cit., pp. 211-215, 


No. 499] DWARF FAUNAS 475 


Atlantic. De Lapparent® states that this western por- 
tion has a few of the Atlantic species but all of reduced 
size. A comparison of British and Spanish coast species 
gives the same result. Haliotis tuberculatus? is larger 
at Guernsey than on the Spanish coast. The difference 
of temperature between the two localities may be another 
factor in causing this dwarfing. 

(c) Change due to an Increase of H.8S.—The presence 
of much of this heavy gas in an enclosed or partially en- 
closed basin would prevent the presence of living organ- 
isms and hence the only fauna which sediments deposited 
here could contain, would be free-swimming or floating 
individuals. This pelagic fauna contains besides fish, 
pteropods, and especially larval forms of almost every 
animal group. Thus the sediment of such an enclosed 
basin would contain small shells, embryonic in character, 
pteropods and a few fish. Andrussow’ has shown that 
in consequence of the greater salinity and density of the 
deep water, the Black Sea shows only slight evidence of 
vertical currents. Such currents are apparent only to a 
depth of 125 fathoms, and hence only to this depth is there 
sufficient oxygen for the support of animal life. Ata 
depth of 100 fathoms the separation of H,S is observable, 
increasing in amount with the increase in depth. The 
separation of H,S is regarded as due to the agency of 
microbes (Sulfobacteria) living upon animal remains of 
the free-swimming and floating forms of life sunk to the 
bottom. It is attributable in part also to the derivation 
from sulfates. Hand in hand with the separation and 
enrichment in H.S is the diminution in sulfates in the 
sea water, the separation of the carbonates and of FeS. 
In the great depths of this sea the bottom is covered with 
black or dark blue mud in which are abundant remains of 
free-floating diatoms, fragments of quite young pelecy- 
pods, and minute grains of CaCO,, and much FeS. 

1 Clarke. N. Y. State Mus. Mem., 6, 200. 

+ Manual of Geology, 4th ed., p. 121. 

ë Traite de Geologie, 5th ed., 1, 132. 

$ Forbes. Loe. cit., p. 171. 


476 THE AMERICAN NATURALIST [ Vou. XLII 


2. Influence of Mud and other Mechanical Impurities in 
the Water.—Though the western Mediterranean contains 
a dwarf fauna, yet it is the eastern part which is especially 
so characterized. This is attributed by de Lapparent’ 
to the presence in the water of the eastern basin of many 
very fine particles of solid matter (Nile sediment) which 
becomes deposited only very slowly. A similar cause ap- 
parently aided in dwarfing some of the faunas of the 
Windsor (Nova Scotia) Carboniferous, also those of the 
Cobleskill, Rondout, Manlius, Bertie, ete. 

3. Influence of a Floating Habitat.—Forms which live 
attached to floating seaweed will tend to be small owing 
to the fact that the increased weight of the individual due 
to growth will cause its sinking with its attached seaweed 
before the attainment of large size. Hence only the 
smaller individuals would occur on the seaweed or in the 
sediment beneath. Fuchs has shown? that in the eastern, 
shallower part of the harbor of Messina, the sea is now 
filled with different kinds of alge, densely crowded 
together. This seaweed thicket swarms with small mol- 
lusks, seeking here food and protection. Here are species 
of Rissoa, Trochus, Turbonella, Columbella, Marginella, 
Cerithium, Cardium, Cardita, Lucina, Area and Venus, 
but they are throughout of smaller size than normal. 
This dwarf fauna is thus not the result of stunted growth 
but is very probably due to the fact that the alge can not 
support large and heavy shells. Such dwarfing and also 
thinning of shells fastened to seaweed (giant kelp) 
Arnold’? notes in the case of Pecten latiauritus vat. 
fucicolus of the California coast. This in its floating 
habitat far from shore is not subjected to the shock of 
the breakers, and hence the shell not only remains thin 
but also gradually loses its ribbed ornamentation. P. 
latiauritus likewise grows attached to kelp but when near 
shore it is more strongly sculptured than when living in 
deeper and quieter waters. 

* Loc. cit., 5th ed., 1, 132. 

°’ Walther. Einleitung in die Geologie, p. 33. 

» U. 8. G. S. Prof. Paper 47, p. 131. 


No. 499] DWARF FAUNAS i 477 


The ability of mollusks to reproduce before the attain- 
ment of full size accounts for the perpetuity of such 
dwarfed species. Semper, in reference to oysters and 
fresh-water mussels, says on this point: 

“ Where formerly really gigantic pond mussels were found, now only 
quite small ones occur; and it is well known that the European oysters 
are gradually becoming smaller. This results from the circumstance 
that both these mollusks are capable of reproduction while they are 
still quite small, and now never grow to their full size, retire they 
are destroyed before they have accomplished their full grow 

A probable fossil example is the dwarf ieee of the 
Ohio Black shale. 

4. Variations in Temperature.—The influence of tem- 
perature upon the size of the animal is well illustrated by 
an experiment of Semper :1? 

“T found by experiment that this animal (Limnea stagnalis) when 
young first begins to assimilate food, and consequently to grow, when 
the water is about 12° C.; at the same time a temperature much below 
has no injurious effects on the animal’s life, though it entirely prevents 
its growth. ... Assuming that a young Limnewa were placed in a 
lake or strane! of which the temperature constantly exceeds the mini- 
mum at which the snail can begin to grow, during only two months of 
the year, while it never perhaps reaches the high optimum 25°, the 
mollusk will be unable to attain its due proportions during the first 
year, or to grow to its full size even during the second, and thus a 
dwarfed form will inevitably arise. This dwarfed form will still be 
able to reproduce and multiply itself, for the maturation of germinal 
matter—the ovum and the sperm—takes place during the winter and 
early spring, at a time when the low temperature of the water hinders 
all grow The optimum of warmth for sexual processes is much 
lower than that for growth. Thus a permanently diminutive race might 
arise if the conditions of temperature above described remained con- 
stant for several succeeding years in the lake or streams in which the 
young mollusks or the eggs have been deposited.” 

But not only does too low a temperature produce 
dwarfing but when the temperate or polar species are 
introduced into water warmer than their optimum, they 
likewise become smaller.** 
1 Semper. Animal Life as affected by the Natural Conditions of Exist- 
ence. D. Appleton and Co., 1881, p. . 

2 Loe. cit., pp. 108 and 109. 

18 Semper. Loe. cit., p. 118. 


478 THE AMERICAN NATURALIST [ Vou. XLII 


Dall says:'* ‘‘As in mammals and birds so in Pectens 
the same species in the northern part of its range is larger 
than in the south unless its habitat is distinctly trop- 
ical.’’> So too the slight excess of temperature, 3° 
within the Mediterranean over that of the Atlantic in 
corresponding latitudes may help to cause the dwarf 
fauna within that basin. 

Mobius mentions'® that the same mollusks living on the 
coast of Greenland and in the Baltic Sea are in the former 
very large and in the latter small and thin-shelled; this 
variation he attributes to the constant temperature in the - 
former case and the very great extremes in the latter. 

The dwarf faunas of the Black and Caspian Seas are 
doubtless partly due, according to Forbes,'* to the great 
extremes in temperature which they experience between 
winter and summer. 

5. Change due to Extremes in Depth of Water.—For 
each organism there are certain limits of depth of water 
in which it best flourishes ; outside of these in either direc- 
tion there naturally results a tendency towards pauperiza- 
tion. 

(a) Very Shallow Pools.—Semper'® took specimens of 
Limnea stagnalis, hatched from the same mass of eggs, 
and placed them in aquaria containing different volumes 
of water. ‘‘ All the animals were under equally favorable 
conditions’’ (as to food, temperature, gases, ete.) ‘‘irre- 
spective only of the volume of water which fell to each 
animal’s share; this varied at most between 100 and 2,000 
c.c.” The result showed that ‘‘the smaller the volume of 
water which fell to the share of each animal, the shorter 
the shell remained.’’ The number of whorls was the same, 
four, but the average length of the shell in the 100 c.c. of 
water was }-inch, while in the 2,000 c.c. volume it was 
3-inch. 

“Arnold. U. 8. G. S. Professional Paper 47, p. 133. 

= See also Weller, Pal. N. J., 4, p. 77. 

1%*Semper. Loe. cit., p. 132. 

" Loc. 0t. Pi SiL 

* Loe. cit, Pe IGE 


No. 499] DWARF FAUNAS 479 


(These measurements were taken from the figures.) 

(b) Great Depths.—The pauperization of faunas with 
increase in depth appears to be due primarily to the 
decrease in light, which is essential to plant growth, and 
thus indirectly to animal life. Secondarily it is due to the 
decrease in temperature, the increase in the heavier con- 
tents of the water, and the greater pressure with depth. 

In Geneva Lake the deep fauna is small and sluggish 
while their surface representatives are larger and active. 

In abyssal ocean faunas there are few mollusca, and 
these are small, translucent, and white, with few crabs 
and annelids, but many echinoderms and porifera.'® 

With decrease in size from higher to deeper regions 
there is further pauperization, evidenced in the loss of 
brilliant coloring and variety of pattern. In the Mediter- 
ranean the proportion of colored to uncolored shells at 
depths of 35 to 55 fathoms is 1 to 3; at 100 fathoms and 
over, it is 1 to 18.” 

The very many dwarf or depauperate fossil faunas 
already noted in the literature are doubtless but a small 
fraction of those still unnoted. The causes which are 
active at present in effecting this result were very prob- 
ably equally active during each year of each era some- 
where upon the earth’s surface; so that the total number 
of such examples must be very great. Some of the fossil 
faunas, as for example, that of the Genesee, consist of uni- 
formly small species, a selective agency having discarded 
the larger ones; here no stunting of growth is apparent. 
In such other faunas as that of the Pyrite bed of the 
Tully horizon, all of the individuals are smaller than the 
normal individuals of those species, thus showing very 
decidedly the stunting effect of environment. In still 
ether cases, such as the Tertiary deposits at Steinheim, 
only a portion of the species were affected unfavorably by 
the environment, becoming dwarfed in size or of a bizarre 
shape, while the rest of the fauna were of the normal 
size for the species. 

” Heilprin. Geographical Distribution, p. 262. 

æ Forbes. Loc. cit., p. 189. 


480 THE AMERICAN NATURALIST [Vou. XLII 


The following few dwarf faunas are described in illus- 
tration of the preceding agencies: 

a. Faunas of the Cobleskill, Rondout, Manlius and 
Bertie of New York. 

b. Faunas of the Pyrite bed of the Tully horizon and of 
the Clinton iron ore. 

c. Fauna of the Genesee and Ohio shales; Styliolina 
limestone of New York. 

d. Fauna of the Windsor (Nova Scotia) Carboniferous. 

e. Faunas of the Permian. 

f. Upper Cretaceous fauna of New Mexico and southern 
Colorado. 

g. Tertiary lake fauna of Steinheim, Germany. 

h. Pleistocene ? fauna of the lower Hudson River. 


a. The Manlius, Rondout and Cobleskill formations of 
eastern New York, as well as the Bertie of the western 
part of the state are conspicuous for their dwarf faunas. 
The cause was probably in part the greater density of the 
water and in part the presence of lime mud, making the 
waters impure mechanically. The section of the rocks at 
Howes Cave is as follows :*! 

Coeymans, a typical lime sand rock (calcarenite). 

Manlius, a fully laminated lime mud rock (calcilutite) 
with occasional beds of a lime sand. 

Rondout, lithology as in Manlius but more argillaceous 
in upper portion. 

Cobleskill (Coralline), lithology about the same as 
Manlius. 

(Slight disconformity.) 

Brayman (upper Salina), possibly the equivalent of the 
Bertie of western New York. Shales gray to green with 
traces of gypsum. Many iron nodules.22 

(Great disconformity.) 

Lorraine. 

Deposition was probably continuous from the Cobleskill 
to the Coeymans, as there is no evidence of a stratigraphic 


“ Hartnagel. N. Y. State Mus. Bull. 69, p. 1114. 
“Grabau. N. Y. State Mus. Bull. 69, p. 101 


No. 499] DWARF FAUNAS 481 


break. That some at least of these beds were deposited 
in shallow water and even exposed at times to the sun is 
shown by the presence of cross bedding, ripple marks, 
and mud cracks. <As is usually the case, these faunas 
show more strongly their dwarfed condition when viewed 
as a whole than when distinct individuals are considered; 
for the reduction in size has not been very great in indi- 
vidual cases, but is shown slightly in nearly all of the 
forms. For example, Whitfieldella nucleolata is equally 
small in all three of the formations (Cobleskill, Rondout 
and Manlius) ; the Spirifers, likewise, are conspicuous for 
their small size, S. corallinensis and S. eriensis from the 
two lower horizons and S. vanuxemi from the Manlius. 
Favosites precedens is a small form of F. helderbergie 
found in the two lower horizons. The presence of a lime 
mud seems to indicate that the waters in which deposition 
took place was denser with alkalies than normal sea water, 
otherwise the mud would have gone into solution as is 
usually the case when limestone is eroded. Such abnormal 
conditions would have a dwarfing effect upon the indi- 
viduals living there, as has been noted in the case of the 
Mediterranean. To this unfavorable influence would be 
added the mechanical impurities of the mud, for on ac- 

count of the shallowness of the water, the mud would © 
probably be kept by the waves in an almost constant state 
of suspension. The occurrence of these dwarf faunas be- 
tween the periods of small exceedingly dense seas or 
lakes, depositing salt and gypsum, and the normal marine 
conditions of the Helderbergian is an additional proof of 
the greater-than-normal density of the water at that time. 

b. An exceedingly interesting dwarf fauna is that of the 
Pyrite layer in western New York at the horizon of the 
Tully limestone, but where that stratum is otherwise miss- 
ing. This fauna is very fully discussed by Professor F. 
B. Loomis.?* 

The layer is a more or less discontinuous deposit of 
pyrite, appearing as very broad lenses but not over 1 foot 
in thickness. It contains a fauna of not less than 45 

2N, Y. State Mus. Bull. 69, 892-920. 


482 THE AMERICAN NATURALIST [ Vou. XLII 


species, few of which, though adults, are over 2 mm. in 
diameter. The fauna includes 1 blastoid, 15 brachiopods, 
12 pelecypods, 6 gastropods, 2 pteropods, 7 cephalopods, 
1 trilobite, and 2 ostracods. These have all, however, 
been dwarfed until their average size is only one fifteenth 
that of the same species in the preceding Hamilton. The 
cause of this dwarfing is suggested to be the presence of 
much iron in solution and the gases arising from the 
decaying vegetable and animal matter. ‘‘The iron in the 
water, as ferrous carbonate, was probably precipitated by 
the sulfuretted hydrogen’”’ from the organic matter, and 
thus formed pyrite (FeOCO, + H,S=FeS + CO, + 
H,0}.** 

That iron in the water has a dwarfing effect was shown 
by experiments upon fishes and tadpoles?® which in eight 
months had been retarded in growth from three to five 
mm. The same is apparently shown in the fauna of the 
oolitic iron ore of the Clinton beds; in these beds at 
Rochester, N. Y., the species have ‘‘an average of about 
one third the diameter of the same species in the beds 
just above and below.’’2¢ 

The same condition was noticed in similar beds in Ken- 
tucky. 

The following list will give a general view of the aver- 
age size of the dwarfed forms. Loomis gives the average 
measurement of each species, 

Spirifer fimbriatus mut. pygmeus Loomis is shown to 
be one twenty-fifth the normal size of the species. 

Nucleospira concinna mut. pygmea Loomis is one 
fifteenth that of the species. 

Tropidoleptus carinatus mut. pygmeus Loomis is one 
fifteenth. 

Nucula lirata mut. pygmæa Loomis averages one tenth 
the size of the normal species. 

Paracyclas lirata mut. pygmea Loomis is only one 
twentieth. 

** Loc. cit., p. 920. 

* Loc. cit., p. 895. 

* Loc. cit., p. 895. 


No. 499] DWARF FAUNAS : 483 


The same species of gastropods and cephalopods vary 
considerably in size, much more so than do the brachio- 
pods. 

Since ‘‘iron solution in water tends to settle gradually 
to the bottom, as was found in experimenting on the fishes 

. it is not surprising to find that the brachiopods, 
which are either sessile or lie on the bottom, are the most 
dwarfed.’’?* The brachiopods are seldom one fifteenth 
the normal in size, nor do they vary much from this; while 
the gastropods and cephalopods, groups of greater 
freedom of motion often vary in the same species from 
one twenty-fifth to one half the normal size; those which 
evidently grew up in this iron water being much smaller 
than those which entered it when partly grown. ‘‘ All of 
these fossils then represent cases of arrested develop- 
ment, with the understanding that the arrest is at no given 
point but all through the development.’’*s It is thus a 
ease rather of retarded development or bradygenesis. 

These retarded individuals appear like the young of 
earlier Devonian types. 

c. From analogy with the Black Sea deposit, Clarke?’ 
conceives that the black, very thinly and evenly laminated 
shales of the Genesee in western New York, with their 
dwarf invertebrate fauna and fish, with their abundant 
segregation of iron sulfide, limestone nodules, etc., are 
likewise the result of accumulation in waters of great 
depth and imperfect vertical circulation. Dr. Clarke 
notes the presence of surface ocean currents in this 
region. He thus interprets the Styliolina limestone, four 
to six inches thick, at the base of the Genesee in western 
New York, as essentially a pteropod ooze caused by the 
meeting of a cold northern current and a warm southern 
one bearing these pteropods. The cold current thus acted 
as a barrier to the northwest spread of these pteropods. 

An accessory agent in the production of this dwarf 

* Loc. oit., 898. 


2 Loc. cit., p. 900. 
* Loc. cit., p- 201. 


484 THE AMERICAN NATURALIST [ Vou. XLII 


fauna of the Genesee may have been the presence of a 
sargasso sea as suggested years ago by Newberry for a 
similar fauna in the Ohio black shales. The Genesee 
and Ohio black shales, occurring from New York to Vir- 
ginia and west to Kentucky and Indiana, contain through- 
out their whole extent some or all of the following small 
species: Lingula spatulata, L. ligea, Schizobolus concen- 
tricus, Chonetes scitulus, Leiorhynchus quadricostatus. 
These species are not only small, but also thin, the largest 
or last named being very frequently if not usually crushed 
through the pressure of the overlying sediment. This 
smallness and thinness apparently indicates a habitat for 
the living animals where they were not subjected to the 
shock of waves as are shore-living species. 

d. At Windsor, Nova Scotia, a very fossiliferous lime- 
stone, of Carboniferous age, occurs between conglom- 
erate, sandstone and a black shale of the same age below 
and coal measures of sandstone and coal above. The 
coal is seen in the Joggins region across the bay. The 
shallow water or terrestrial origin of the former set of 
beds is indicated by the predominance of the coarse 
clastic sediment, the presence of ripple marks, footprints 
and Lepidodendra. A similar origin accounts for the 
latter. 

The fossils of these Carboniferous limestones show the 
effect of the unfavorable environment in which they lived 
at the time these limstones were being deposited. 
Brachiopods suffer most, being depauperate throughout 
the series, the pelecypods, though much dwarfed, suffer 
less diminution, while the cephalopods were the most 
resistant to the dwarfing agencies; i. e., the more closely 
a species was confined to a particular habitat the more 
dwarfed were the resultant adult forms. 

The uniformly small size of most of the species is 
attributed by Dawson to two causes :*! 

1. Variation in depth and content of the water as 


» Williams. U. S. G. S. Bull. 210, 110. 
a Acad, Geol., p. 284. 


No. 499] DWARF FAUNAS 485 


illustrated by one layer which is brown and impure, in- 
dicating deposition in shallow and turbid water. In this 
layer the brachiopods are especially small and depau- 
perate. Productus cora rarely reaches one inch in 
diameter and the Rhynchonellas are minute. The pelecy- 
pods are very abundant but dwarfed. 

2. The influence of the formation of the beds of gypsum 
and gypseous marls at the time these limestone reefs 
were growing. Dawson ascribes the formation of these 
gypsum deposits to chemical change produced on the 
calcareous beds and reefs by contact of streams charged 
with H,SO,. Such streams are easily accounted for by 
the volcanic activity known to have occurred in this region 
while the shell beds were growing. The great amount of 
CO, released in the change from calcareous carbonate to 
gypsum would surely render unfavorable the water in 
which these limestone-secreting animals were living. 

e. De Lapparent attributes the depauperized fauna of 
the Mediterranean in part to the greater preponderance 
of CO, in the water of that sea over that of the Atlantic. 

One of the most notable facts arising from a study of 
red strata is the very frequent total absence in them of 
all fossils and the often dwarfed and impoverished faunas 
of the associated strata of other colors. Such red beds 
are especially conspicuous in the rocks of the Devonian, 
Permian and Triassic eras. Geikie mentions that fossils 
are practically absent from the red strata of the Old Red 
sandstone of England, but abound in the gray or black.*? 

According to the same author** ‘‘the impoverished 
fauna of the Permian rocks of central Europe is found 
almost wholly in the limestone and brown shales, the red 
conglomerate and sandstone being, as a rule, devoid of 
organic contents.”’ 

In speaking of these same rocks de Lapparent** says 
that ‘‘in northern Europe the mollusks of the upper 

= Textbook of Geol., 2, 1002. 


* Toc. oit, p. 10 
* Traite de Ocologio, 5th ed., 1, 1017. 


486 THE AMERICAN NATURALIST [ Vou. XLII 


Permian are always of small size as if they had lived in 
particularly unfavorable conditions.” The cause he 
gives is that ‘‘there was formed a series of interior seas, 
soon dried up and where the excess of saltness had the 
effect of injuring the development of the mollusks. 
These seas have left here and there important deposits of 
salt and gypsum.”’ 

That this dwarfed fauna was not the normal, open-sea 
fauna of the Permian is noted by a comparison with the 
species of the Alps, the Mediterranean region, and India. 
While in northern Europe the predominating forms are 
pelecypods and brachiopods, with exceedingly few cepha- 
lopods, in these latter more normal regions, the cepha- 
lopods become very numerous and all are of a larger 
size.®5 

It is interesting to note the resemblance of the fauna 
of the Carboniferous of Windsor, Nova Scotia, to that of 
the Permian of northern Europe. According to the de- 
termination of de Verneuil*® several species of brachio- 
pods and peleeypods are common to the two regions, show- 
ing that similar conditions tend to bring about develop- 
ment along similar lines. 

(In this connection Schuchert’s discussion of the ques- 
tion—Is there a Permian system or only a Permian 
_ formation?—is enlightening.) ** 

f. The dwarf fauna of the Cretaceous strata of New 
Mexico and southern Colorado**® occurs in sandy shales 
and shaly sandstones, accompanied by innumerable frag- 
ments of wood. Cross bedding is frequent. The ma- 
jority of the shells are of normal size, but with these occur 
many others which are distinctly smaller than in other 
regions. Lima utahensis Stanton is here only one half as 
large and Lucina subundata M. and H. is also smaller 
than in Utah. Ostrea DE var. nanus Johnson is 

De Lapparent. Loc. cit., p. 

* Davidson. Jour. of Geol. n 109, p. 160. 

A, J. 8., 22, 29-46 and 143-158, 

* Stanton. U. 8. G. 8S. Bull. ee Shiney and Blodgett. A. J. S. 
25, 67. 


No. 499] DWARF FAUNAS 487 


a dwarf form of the species O. anomioides Meek. Ostrea 
lugubris Conrad is a small species resembling the wd 
O. blackii. 

A probable explanation of this fauna and its habitat 
may be drawn from Metzger’s observations*®® upon that 
much-studied shell, Cardium edule. This upon the sand 
shoals of the ocean flats is small, while it attains its maxi- 
mum size off the rugged coasts of Norway and Scotland. 
These Cretaceous strata with their sand, cross-bedding, 
much fragmentary wood, and a marine fauna indicate a 
shallow sea into which emptied some large river, a condi- 
tion probably somewhat similar to that of the eastern 
part of the North Sea at present. 

g. It often happens that while a portion of a certain 
fauna is dwarfed, the rest are of normal size. Hyatt 
discusses an excellent example of this mixture of dwarf 
and normal forms from the Tertiary strata of Steinheim, 
northwestern Germany. 

Into the Tertiary lake at Steinheim migrated four 
varieties of Planorbis levis. The descendants of these 
are divided into the progressive series or those which 
became larger and more robust, and the retrogressive or 
those which became smaller, less robust and distorted. 

The dwarfing of the one series may be explained as a 
sapping of the individual’s energy due to its being in an 
unfavorable environment. It is common to note signs of 
old age appearing immediately after a severe injury to 
the animal.*? 

In gastropods this is often indicated by uncoiling and 
rounding of the whorls, so that these may be looked upon 
as signs of weakness in the animal. Hyatt discusses the 
reason for this as follows: 

“ Among living animals it is a matter of daily experience to find 
some races ineapable of enduring variation in the surroundings to 
which others readily accommodate themselves and even thrive under.” “ 

® Walther. “Einl. in die Geol., p. 32. 

+ The Genesis of the cane Species of Planorbis at Steinheim. Bos. 
Soc. Nat. Hist. Anniv. Mem., 


“Hyatt. Loc. cit., p. 16. 
“Shimer. Old Age in Brachiopoda. Am. Nart., 40, 115. 


488 THE AMERICAN NATURALIST [Vou. XLII 


“ In the individual the effects are shown in the disturbance of the 
laws of growth, producing abnormal or premature weakness or in the 
natural exhaustion of the powers of growth causing senility. A wound 
and its results, whatever they may be, can unquestionably be so 
classified, since it is primarily a severe shock to the system which lays 
additional burdens upon the powers of growth and is usually followed 
if severe by retrogressive metamorphoses or premature old age... 
normal old age simply expresses the normal wearing out of the powers 
of vitalized tissue to sustain itself against the perpetual friction of ex- 
isting physical surroundings. ... When we compare these effects of 
unfavorable environment in producing distortion and decrease in size 
of the individual with the corresponding distortions and decrease in 
size of the retrogressive sub-series there is a certain similarity which 
leads to the supposition that the latter are also probably due to an 
unfavorable environment.” “ 

h. At Storm King, about fifty miles above New York, 
was found in drilling a series of holes across the Hudson, 
an apparently dwarf fauna including only two species, 
Mulinia lateralis (Say), of which there are hundreds of 
specimens and Trivia trivittata Say, of which there are 
but few specimens in our collection. 

(These fossils were obtained by Professor W. O. 
Crosby in February, 1908, and through his kindness these 
facts are presented.) 

These were found:-in but one drill hole, though prob- 
ably the same species are present in the others but 
passed unnoticed in the drilling. They occur 620 feet out 
in the river from the Storm King shore, 40 feet below 
the bed of the river, i. e., about 120 feet below the present 
river or sea level at that point. The Hudson is brackish 
at this point and as far north as Poughkeepsie, as is evi- 
denced by the absence of ice houses below Poughkeepsie. 
Whether in the present bed of the stream there are any 
marine forms growing was not ascertained. The heavier 
sea water might still come up in sufficient amount to 
furnish a marine habitat even under quite fresh surface 
conditions. This dwarf fauna in the abundance of 
Mulinia lateralis suggests Pleistocene age. 

These two species live at present off the New England 

* Hyatt. Loc. cit., p. 15. 


No. 499] DWARF FAUNAS 489 


and New Jersey coasts, in normal marine or but slightly 
freshened water. An average-sized fossil specimen of 
Trivia trivittata is three eighth inch long with a greatest 
diameter of three sixteenth inch. An average size for 
those off the Massachusetts coast is two third inch by 
one third inch. The smaller specimen is less strongly 
ribbed and less nodose. 

One of the larger of the fossil specimens of Mulinia 
lateralis measures five sixteenth inch by one fourth inch. 
The young shells off the coast are small, thin, with 
margins subequally rounded and beaks inconspicuous and 
nearly touching each other; this description applies to all 
of the Hudson River specimens. It does not seem prob- 
able, however, though possible, that so many shells could 
be gathered at random as was done by the drill without 
getting some adults. The more probable explanation 
seems to be that these fossil individuals were living in an 
unfavorable environment, a water less than normally 
saline, and through a consequent sapping of vitality, were 
not able to attain large size. 


SuMMARY 

In the first part of the above discussion was given what 
appear to be some of the principal causes for the dwarfing 
of invertebrate water-living faunas; these were illus- 
trated by present-day examples. In the second part a 
few fossil examples are described with a brief discussion 
of the probable cause of the dwarfing in each case. 

The chief agency is apparently an abnormal habitat. 
A species, for generations used to an environment of sea 
water with a certain unvarying density, temperature, 
clearness and depth, would become so accustomed to that 
state of affairs that a change in one or more of the factors 
would affect it unfavorably. An unfavorable environ- 
ment causes a greater expenditure of vitality in the con- 
tinuance of life than does a favorable one. Hence after 
the maintenance of life itself, there would be less surplus 
energy left for growth. There would thus result a 


490 THE AMERICAN NATURALIST (Vou. XLII 


tendency to smallness of size especially in those species 
having comparatively little vitality to start with. It 
could happen then that from this cause alone either all or 
but a few of the species of a fauna would become dwarfed. 

The hard parts of the animal are so intimately related 
to the soft parts that whatever affects the soft parts is 
immediately impressed upon the building shell. Thus 
whatever ill or good conditions the animal is subjected to 
are expressed in the shell, as are moist and dry summers 
recorded by the annual rings of exogenous trees. 

Two classes of dwarf faunas are noted: (1) Faunas 
where the individuals are of smaller size than that to 
which the species grows under normal conditions; this is 
the resultant of an abnormal habitat. (2) Faunas where 
all the individuals are small but of the normal size of the 
species; in this case some selective action has weeded 
out all the large and heavy species, leaving a dwarf but 
not stunted fauna. Dwarf faunas usually include repre- 
sentatives of both these classes. 

Dwarfing shows itself in two ways: 

1. An acquirement of old age characters by the dwarfed 
animal. Such old age characters as sluggishness, loss of 
external sculpture, teeth, ete., are very common in stunted 
forms. 

2. A retention of youthful characters. That is, the 
animal’s growth takes place so slowly, due to the ab- 
normal environment that saps the vitality, that death 
overtakes it before it has passed through the youthful 
stage, and the animal develops no old age characters. 


NOTES AND LITERATURE 


ICHTHYOLOGY 


Life History of the Eel..—The waters of the northeastern Atlan- 
tic and of the adjacent North and Baltic Seas have been sub- 
jected in recent years to a most elaborate and continuous in- 
vestigation, thanks to government subsidies and international 
cooperation. A coordinated study of the plankton and an in- 
vestigation of the breeding habits and the young of the important 
food fishes and of their migrations and movements, have made 
up the large part of the ambitious program of this International 
Commission. In the allotment of the field it has fallen to the 
Danish Fisheries Bureau to undertake to complete our knowledge 
of the life-history of the common eel. Dr. Johs. Schmidt, with 
the aid of the Danish fisheries steamer Thor and Dr. Peter- 
sen’s young-fish trawl, has added a new, and almost final, chap- 
ter in the solution of this mystery which has puzzled naturalists 
for centuries. 

The suggestion of Dr. Theo. Gill in 1864 that the peculiar 
ribbon-like fish known as Leptocephalus was the larva of the 
Conger eel was subsequently verified by Dareste’s (1874) ana- 
tomical comparisons and Delage’s (1886) successful rearing of 
a Leptocephalus through its metamorphosis into the Conger eel. 
It remained for the Italian zoologists Grassi and Calandruccio 
to demonstrate in 1897 that the larva known as Leptocephalus 
brevirostris was in reality the young of the common European 
eel, Anguilla vulgaris. Their conclusions were based upon ana- 
tomical comparisons, transitional stages, and experimental rear- 
ing of the larval Leptocephalus to the young Anguilla. Most, 
if not all, of the material upon which the work of the Italian 
investigations were based was obtained at or near the Straits of 
Messina where the famous whirlpools bring to the surface the 
organisms of the deeper waters. 

The eel fisheries of northern Europe are widespread and in 
places, especially in the Baltic Sea, they are extensive. There 
were in 1881, 18,491 eel traps in operation along the Swedish 

1 Contributions to the Life-History of the Eel (Anguilla vulgaris Turt.). 
By Johs. Schmidt. Conseil Perm. Intérnational pour Expl. de la Mer. Rap- 
ports et Proces-verbaux, Vol. 5, pp. 137-274, Pls. 7-13. 

491 


492 THE AMERICAN NATURALIST (Vou. XLII 


coast, and in 1900, 22,608 in Danish waters, excluding fresh 
water and the smaller areas of salt water. Yet in spite of these 
extensive fisheries and the wide distribution of the eel along the 
coasts of the Atlantic and its tributary waters in Europe, abso- 
lutely nothing has been known of the spawning grounds, or 
breeding habits of the eels of these more northern waters. Sex- 
ually mature eels have rarely, if ever, been taken. Dr. Schmidt 
records the discovery of but a single sexually mature male eel 
of the silver (migrating) type in shallow waters off the coast of 
Denmark. Leptocephalus larve belonging to the common eel 
(L. brevirostris) have never been taken, until recently, in the 
Atlantic. The specimen taken by the Challenger Expedition in 
the North Atlantic and referred by Günther to this species proves 
upon reexamination to belong to another species having 140 
myomeres instead of the 111-118 characteristic of L. brevirostris. 

In 1904 a single example of this latter species was captured by 
Dr. Schmidt in the tow nets of the Thor west of the Faeroes, 
and a few months later Dr. Holt, of the Irish Fisheries Bureau, 
took a second specimen west of Ireland. These captures gave 
the clue which Dr. Schmidt has most successfully followed. In 
the next two years Leptocephalus was discovered by Dr. Schmidt 
in large numbers in mid-summer to the west of the British Isles 
and France over depths of 1,000 meters. The transition stages 
between the hyaline pelagic larve in the Leptocephalus stage 
and the colorless ‘‘ elvers °’ which have long been known along 
the northern and western coasts of Europe were also found by 
the Thor but at the close of summer and in the autumn. 
After a thoroughgoing investigation of these grounds and of the 
data regarding the movements and distribution of the young 
elvers along the coasts of Great Britain and continental Europe 
Dr. Schmidt comes to the following conclusions. 

The common eel of northern Europe spawns in the Atlantic 
Ocean west of the British Isles and southward at least as far as 
the northern coast of Spain. The essential features of the 
spawning ground are (1) a depth of at least 1,000 meters and 
(2) a temperature at this depth above 7° ©. This belt is a 
relatively narrow one along the edge of the continental shelf 
as it rises from the Atlantic basin. Leptocephalus larve have 
long been known in the Mediterranean and a much greater ex- 
tension of the spawning grounds beyond the known limits to the 
south is not improbable. The Atlantic basin with its greater 
depths and lower temperatures appears to afford an effectual 


No. 499] NOTES AND LITERATURE 493 


barrier between the American and European eels (Anguilla 
chryspa and A. vulgaris). Eels of European streams approach- 
ing sexual maturity and migrating seaward must travel to the 
edge of the continental shelf to reach suitable spawning grounds. 
The Baltic and North Seas are too shallow, and waters to the 
west of Norway are deep enough but their temperatures are 
too low. 

The eels, as they migrate, undergo a considerable change in 
appearance, passing from the stage known as the yellow eel to 
that of the silver eel, in which feeding is suspended, the digestive 
tract is shrunken and sexual glands show some enlargement. 
The direction of migration in the Baltic in the autumn is out 
toward the open sea. The paths of migration are usually paral- 
lel to the coast and in shallow water, though eels have been known 
to cross channels 60 meters in depth. The direction and rate of 
migration was worked out by Dr. C. G. Joh. Petersen, the director 
of the Danish Fisheries Laboratory, by means of marked fish. The 
rate of movement in the migratory season is about 15 kilometers 
per day. The eels in these shallow waters, where their presence 
is revealed by commercial fishing, are none of them sexually 
mature. Their further movements are unknown but the pre- 
sumption is that they continue their course toward the open sea 
and to the edge of the continental shelf. A single capture in 
the English Channel twenty miles from land confirms this con- 
jecture, as do also the captures made by Grassi and Calandruccio 
in the whirlpools at Messina, where occasional specimens of the 
common eel are brought to the surface, which differ materially 
from those taken in shallow waters. They are silver eels in 
which the breeding dress is further accentuated by darker color, 
the anterior border of the gill openings and the pectorals become 
an intense black, the eyes also become enormously enlarged and 
the sexual organs show greater maturity. Maturing eels have 
also been taken from the stomachs of the sword-fish and in the 
collection of Prince Albert of Monaco is a large eel taken from 
the stomach of the cachelot. These facts in conjunction with 
certain testimony on the part of fishermen suggest the possibility 
of a pelagic or bathypelagie habitat of the eel in its migration 
to the open sea. 

The larve Leptocephalus brevirostris of the eel are true 
pelagic organisms, as is shown by their entire organization. 
Neither their structure nor their distribution indicates any rela- 
tion to a bottom habitat. In life they are perfectly transparent 


494 THE AMERICAN NATURALIST [ Vou. XLII 


and are found in association with typically pelagic organisms 
such as Salpa, Cymbulia and Phronima, as well as the young of 
other pelagic or deep-sea fish, among which are five additional 
species of ‘‘Leptocephalus.’’ They have also the leisurely move- 
ments characteristic of many pelagic animals. 

The pre-Leptocephalus stages of the eel are as yet wholly un- 
known. The earliest season of investigation has been the month 
of May and at this time the pelagic larve are found during the 
day in greatest abundance in levels at a depth of about 100 m., 
but rise to the surface levels at night. This distribution of the 
youngest known stages leads Dr. Schmidt to surmise that the 
eggs of the common eel are bathypelagic, and that the larve as 
they develop rise to the upper levels. 

The pelagic larve appear to reach the height of the larval 
stage of development in June and cease active feeding, but do not 
as yet show the regressive phenomena which characterize the 
period of metamorphosis. They have also reached their maxi- 
mum larval size 75 (60-88) mm. Both upper and lower jaws 
are equipped with long slender grasping teeth. No pigment is 
found in the body except in silvery iris of the eye. The digestive 
tract at this time extends through about two thirds of the length 
of the body. l 

The larval stage is followed by a long period of metamorphosis 
during which the form of the body changes from that of a color- 
less ribbon-like band to the pigmented cylindrical type with 
differentiated head and tail. The pelagic mode of life is aban- 
doned and the young eels or elvers adopt the bottom habitat 
in shallow coastal and fresh waters into which they have mi- 
grated from the open sea. This period of metamorphosis occu- 
pies the entire year or more, during which no food is taken. The 
body gradually decreases in size as the metamorphosis proceeds, 
diminishing from an average length of 75 millimeters in the high 
seas in June to 65 millimeters a year later in coastal waters. The 
digestive tract shortens during this period from two thirds to 
one third of the total length of the body. Mandibular and 
vomerine teeth appear and dermal sense organs develop about 
the head. 

During this long period of metamorphosis the Leptocephalus 
larve migrate slowly from their habitat above the 1,000-meter 
line shoreward. According to the recent summary of observa- 
tions published by Professor Gilson, they reach the coasts of 
Spain and Ireland in October-December, and the western coasts 


No. 499] NOTES AND LITERATURE 495 


of France and England and the eastern shores of Seotland in 
January—February. In March the tiny elvers swarm along the 
shores of the Netherlands, Denmark and Norway and continue 
to arrive there during the month of May. Danish waters and the 
western Baltic form the eastern limits which the eel reaches in 
the elver stage. Their farther migrations into the Baltic and up 
the rivers of northern Europe are accomplished during the period 
of rapid growth which now ensues. 

The extensive eel fisheries of Europe thus depend upon the 
migratory habit of a true Atlantic deep-water fish which seeks 


Metamorphosis of the Eel (Anguilla vulgaris), 


_ 


figs. 1-2, 1st stage (Leptocephalus brevirostris). Figs. 3-6, 2d stage. Figs. 


1gs 


í-8, 3d stage. Figs. 9-10, 4th stage. Figs. 11-12, 5th stage. Fig. 13, 6th stage 


496 THE AMERICAN NATURALIST [ Vou. XLII 


fresh-water streams and lakes for its period of growth but re- 
turns to the deep sea to spawn. CHARLES A. Koror. 


The Valves in the Heart of Fishes.—The following note by Dr. 
H. D. Semor, of the College of Medicine in Syracuse University, 
New York, on the valves in the heart of fishes should be put on 
record. 

It may be noted that in the so-called ganoid fishes there is 
more than one row of valves and from these ganoid fishes are 
derived the herring-like fishes. Some of these, as Dr. Senior 
has noted, have two rows of valves. Others have but a single 
one as in ordinary fishes. 

“With regard to the question of teleosts having a conus arteriosus 
provided with more than one row of valves: In addition to Albula’* 
which has long been known to have two rows, I have found a conus 
with two rows of valves (each row having two cusps) in „Tarpon atlan- 
ticus? Megalops cyprinoides} and in Pterothrissus gissu.* I think this 

ist will prove to be complete, as I have examined, with a negative 
result, Elops,’ Chirocentrus, Chanos,’ Dorsosoma,’ Notopterus, Pomo- 
ome Alosa, Brevoortia, and Boas has examined Osteoglossum.° 
“ A well-marked or vestigial conus arteriosus with one row of valves 
only, occurs in Elops‘ Hyodon,’ Chirocentrus, Chanos, Notopterus,° 
Osteoglossum? and Dorosoma. That it also occurs in other allied 
genera, I have little doubt. When I collect enough specimens, I intend 
to deseribe and figure the conus (or vestige) in a sufficient number to 
indicate its mode of disappearance.” Davin S. JORDAN. 


PARASITOLOGY 


The Hereditary Transmission of Germ Diseases.—The earlier 
views which favored hereditary transmission of germ diseases 
have been subjected for nearly half a century to careful scrutiny 
at the hands of bacteriologists and are now generally rejected. 
Experimental evidence has been furnished from many quarters 
that the supposed cases are due to a contamination of the off- 
spring during transit through the maternal passages at birth, or 

*Stannius. Bemerkungen iiber das Verhaltniss der Ganoiden zu den 
Clupeiden, insbesondere zu Butirinus Rostock, 1846. Boaz. Morph. Jahrb., 
Bd. 6, p. 527. 

*Senior. Biol. Bull., Vol. XII, p. 146. 


* Senior. Anatomical Record, Vol. 1, No. 4, p. 82. (Am. J. of Anatomy, 
Vol. VI, No. 4.) 

5 My own notes, unpublished. 

‘Boaz. Morph. Jahrb., Ba. 6, p. 527. 


No. 499] ‘NOTES AND LITERATURE 497 


oceasionally to infection in utero, although in the majority of 
cases the cord and placenta form a barrier to the transmission 
of bacteria. Even when the bacteria gain entrance into the fetus 
there is no adaptation to the reproductive process. 

Until very recently the part played by animal organisms in 
the transmission of diseases has been regarded as of very minor 
importance, and for the few known instances the same view rules 
with reference to conditions of transmission as already noted for 
bacteria. In the ease of malaria, the oldest known protozoal 
disease, many experiments have been made to determine the oc- 
currence of transmission in utero, from mother to offspring, and 
not only the general facts but also the details have been estab- 
lished. 

A long series of able investigators, among them our own W. S. 
Thayer, have found that the malarial organisms present in the 
maternal blood do not occur in the blood of fetus and of the new- 
born. It has been generally agreed that these hæmatozoa can 
not traverse the placenta from the pregnant mother to the fetus. 
Moreover Bignami et Sereni demonstrated that the fetus lacks 
not only the parasites, but also the anemia which often charac- 
terizes the mother. The subject has been subjected to most 
careful reexamination at the hands of two Greek investigators." 
In every case the maternal blood contained malarial parasites in 
greater or less abundance. In blood taken from ‘the maternal 
face of the placenta, parasites were abundant, in that from the 
opposite or fetal face they were absent or very rare. In blood 
taken from the umbilical cord and from the liver, kidney and 
other organs at autopsies, not a single parasite was demonstrated. 
Thus they confirmed absolutely the view that these haematozoa 
do not traverse the placenta. 

An interesting departure from these conditions is afforded by 
recent investigations on other disease-producing protozoa. The 
experiments are not extensive and in some cases contradictory. 
Thus Massaglia? infected pregnant guinea-pigs with trypano- 
somes. In one case at death the liquor amnii contained trypano- 
somes, in the other not; but in neither case could any parasites 
be found in the blood of the fetus. On the other hand, Pricolo* 
found in mice a trypanosome which was capable of traversing 

mere et Cardamatis, Centr. Bakt. und Par., Orig., 43, 181. 
az. Ospedali ed Clinichi, 1906, 12. 
i sie Bakt. und Par., Orig., 43, 231. 


498 THE AMERICAN NATURALIST [ Vou. XLII 


the placenta and affecting the young in utero. It also appeared 
to multiply rapidly in the fetal circulation. 

In eases of congenital syphilis, Treponema pallidum has been 
shown to be present in small numbers in the blood taken from 
placenta and cord and undoubtedly has the power to pass through 
the placental tissue from maternal to fetal circulation. While a 
final decision can not be reached at present, the weight of evi- 
dence favors the view that Treponema is an animal rather than a 
bacterium. In some closely related forms the conditions have 
been more definitely established. Thus in Spirochaeta duttoni, 
the cause of African relapsing fever, Breinl and Kinghorn,‘ 
in four rats and one guinea-pig, demonstrated the passage of the 
spirochete through the placenta into the fetus. The parasites 
were found in the placenta in approximately the same numbers 
as in the heart blood of the mother, yet in very meager numbers 
in fetal blood. There was no tendency to abort, yet a large per- 
centage of young died shortly after birth. The spirochetes from 
fetal heart blood showed themselves virulent on inoculation. 

These and similar cases among animal parasites are not sur- 
prising. They differ from the accidental contamination of the 
young at birth in the case of bacterial diseases only in that the 
infecting agent is capable of migration through solid tissue and 
thus passes barriers in the placenta which constitute obstacles to 
the passage not only of bacteria but also of some other animal 
organisms, like the plasmodium already noted, which do not 
penetrate tissues, but pass their entire existence in the blood 
stream. So far as known there is no adaptation of the parasite 
to special conditions and the infection of the new generation in 
utero does not differ biologically from the infection of a new 
organ as the parasites wander through the body of the host. 
The transmission of the disease to a second generation is a 
biological incident and bears no especial relation to the repro- 
ductive organs or function. 

Certain cases are known, however, in which the conditions are 
radically different. One of the first of these was the demonstra- 
tion by Koch® of the life history of Babesia (= Piroplasma) 
bigeminum. In this he was able to determine that one form in 
development was found in the eggs of the tick by which the 
organisms are transmitted. This stage appears to be the means 
by which the young larve of the second generation of ticks are 

* Liverpool sage Trop. Med., Mem. 21. 

* Zeit. f. Hyg., 54, 1. 


No. 499] NOTES AND. LITERATURE 499 


infected. It has long been known that young produced by in- 
fected ticks will transmit certain diseases even though they have 
never come in contact individually with cases of the disease. 
The demonstration in the ova of such forms as discovered by 
Koch furnishes evidence of the manner of this transmission. 
Christophers*® has followed carefully the formation of these 
bodies and their penetration into the ova, where they become 
spherical resting stages. He has also traced these bodies through 
larva to nymph and thinks that when the latter become adult 
the parasites have migrated into the salivary glands. It has 
long been known that Texas fever was conveyed by the progeny 
of infected ticks, but the demonstration of the infective agents 
has heretofore eluded observation. 

Several authors, among whom Carter? may be mentioned, have 
shown that Spirochaeta Duttoni infects the ova of ticks which 
suck the blood of hosts harboring this parasite, that the organisms 
multiply in the ova and that by them the new generation of ticks 
is infected and may transmit the disease produced by the para- 
site. Other instances of the same type might be added to the 
list. The process may, however, go one step farther. 

Recently reported investigations of several observers show that 
in the housefly a parasitic flagellate infects the ova and thus the 
subsequent generation of its host. Since the host is no longer a 
blood-sucking insect, there is no possibility of a sanguinicolous 
generation of the parasite in some other host. Probably the 
hereditary method is the only one by which the parasite is 
‘propagated and new generations of flies are infected, although 
it is possible that encysted forms, discharged in the feces, might 
be taken up in the food of some other fly. It is interesting to 
note in this connection some work done in my laboratory by Mr. 
L. D. Swingle, who has followed out the life-history of a similar 
flagellate parasitic in the sheep-tick.. As is well known, this host 
is really a degenerate fiy, and this parasite has, so far as can be 
ascertained, no relation to the blood-sucking habit of its host. 
It infects the ova and in a resting stage awaits there the devel- 
opment of the next generation, but no stages were found indi- 
cating any other method of transmission. 

These instances just outlined differ radically from those noted 
at first in which the organisms traverse the placenta and gain 
entrance to the offspring in utero. The latter involve, as already 

è Indian Med. Gazette, December, 1906, 467. 

* Ann. Trop. Med. and Par., 1, 157. 


500 THE AMERICAN NATURALIST [ Von. XLII 


indicated, no modification or adaptation in the process of repro- 
duction. But in the infection of the ova with a resting stage is 
involved a selection both of the definite organ and of the cell 
which becomes infected. Further, the parasite must assume 
a resting condition adapted to undergo successfully the changes 
indicated in the development of the adult insect from the eggs 
and sometime in the latter process must reach the suitable loca- 
tion. In the ease of the fly such a location will be the alimentary 
canal of the insect, while in the tick which is to transmit the 
disease-producing organisms the suitable location will be rather 
the salivary glands, as suggested by the observations of Chris- 
tophers. In any event the interrelations are evidently extremely 
complicated. The infection of the fetus by tissue-penetrating 
protozoa is purely incidental; the infection of the ova and 
through them of the second generation is a complicated bio- 
logical process, involving essential modification in the life-history 
of the parasite and important morphological adaptations to new 
conditions of life. 


A Society for the Destruction of Vermin.— Recent demonstrations 
as to the agency of mosquitoes, flies, bedbugs, rats and other 
household pests in transmitting serious diseases has taken such 
active hold on the British mind that there has been organized in 
London a Society for the Destruction of Vermin. It is incor- 
porated under the Board of Trade regulations as a public associa- 
tion not formed for the object of making profit. The work the 
society has set itself to do is: (1) Collect information from all 
sources on the distribution and life-history of vermin. It will 
pay special attention to the part played by vermin in disease 
causation. (2) Disseminate as widely as possible the acquired 
knowledge by means of the general press, and also by special 
reports, leaflets and lectures. It will endeavor to make known 
to the public the dangers connected with each kind of vermin, 
the necessity for exterminating certain species, and the best 
means of destruction. (3) Carry out experiments in the field, 
test any: promising measures suggested for the destruction of 
vermin, and, if funds permit, distribute gratuitously, to such 
persons as are unable to afford the expense, the necessary sub- 
stances and apparatus. (4) Organize, in cooperation with other 
associations and publie bodies, a practical eampaign for the de- 
struction of vermin. To conduct operations an active committee 
has been formed. (5) Encourage and assist in any legitimate 


No. 499] NOTES AND LITERATURE 501 


way the operations of rat and sparrow clubs and similar bodies. 

The services of the society will be placed at the disposal of 
municipalities, boards of health, agricultural societies, shipping 
and deck companies, and other bodies interested in the suppres- 
sion of vermin. The society has already received the support of 
many eminent physicians, bacteriologists and chemists, together 
with that of agricultural and poultry organizations, public as- 
sociations and other bodies 

H. B. W. 


PLANT CYTOLOGY 


Polar Organization of Plant Cells.—Research in plant cytology 
has resulted in conflicting views as to the extent of such polar 
organization of plant cells as is well known for certain animals 
from the work of Rabl, Van Beneden, Flemming and others. 
Some of the alge present clear evidence of such polarity, the 
best known example being Stypocaulon, which has a center in 
the form of an aster with a centrosome, present at the side of the 
resting nucleus and dividing previous to each nuclear division, or 
mitosis, to establish the poles of the spindle. A similar aster is 
present at the tetraspore mother-cells of Dictyota. Other alge 
such as Fucus and Corallina show highly developed centrospheres 
at the poles of the spindles, but investigations so far indicate that 
they are formed de novo with each mitosis and that there are 
no permanent centers associated with the resting nuclei to give 
polarity to the cells. 

The research of recent years on the cells (particularly the 
spore mother-cells) of pteridophytes and spermatophytes has 
failed to support certain claims for the presence of centrosomes 
in these groups of plants, and has indicated that their cells are 
without visible polar organization. As nuclear division ap- 
proaches in the spore mother-cell fibrille appear in the cyto- 
plasm, at first arranged radially, but later becoming associated in 
cone-shaped groups (constituting the multipolar stage), and at 
last arranging themselves to form the two opposite poles of the 
final bipolar spindle. Among the bryophytes, the liverworts 
have received considerable attention. In this group well-differ- 
entiated centrospheres are present at the poles of the spindles, 
but these are described by all investigators as arising de novo 
and they have not been reported in association with the resting 
nuclei. 


502 THE AMERICAN NATURALIST [Vou. XLII 


The subject of polar organization in plant cells has received 
especial attention recently through the work of Harper’ on the 
mildews (particularly Phyllactinia), and that of his student 
Marquette? on Isoetes and Marsilia. Harper found in the ascus 
of Phyllactinia an especially favorable subject for the study of 
the organization of the resting nucleus and its mitosis in rela- 
tion to a central body, which is a permanent organ of the cell and 
gives to the nucleus and cell a definite polar organization. The 
central body lies on the nuclear membrane and the chromatin 
elements in an early stage of mitosis have the form of 
strands, each one attached independently to this center. Even 
in the resting nucleus, when the chromatin has the structure of a 
network, its attachment to the central body is evident and indi- 
cates that the strands have an individual connection with the 
central body as a nuclear pole. During the prophase of mitosis 
the central body divides and the two portions move apart to 
become the poles of spindle and, at the completion of mitosis, 
each remains connected with a daughter nucleus, thus main- 
taining its polarity. Furthermore, in the process of nuclear 
fusion within the ascus each nucleus contributes its complete 
polar organization so that the resulting fusion nucleus has for 
a time two central bodies and two independent groups of chro- 
matie elements, which later gradually fuse into a single system 
with one central body. 

Marquette has discovered a remarkable polarity in the leaf 
cells of Isoetes. Each resting cell contains a large starch-con- 
taining body, which lies so closely pressed against the side of 
the nucleus that the latter is usually indented. Sometimes the 
body is present without the starch grains that usually render it 
very conspicuous. Previous to nuclear division this polar struc- 
ture elongates and divides by constriction and the two parts 
draw apart so as to form a furrow on the surface of the nucleus. 
The separated halves then come to lie at opposite ends of the 
nucleus, which has become somewhat elongated. These develop- 
ments take place before the appearance of the chromatin gives 

*Harper, R. A. Sexual Reproduction and 7 foo year be of the 
Nueleus in Certain Mildews. Pub. Car. Inst., No. 37, F 

2 Marquette, W. Manifestations of Polarity in ce Cells which Appar- 
ently are without Centrosomes. Beih. Bot. Centralbl., XXI, p. 281, 1907. 
Concerning the Organization of the Spore Mother-cells of Marsilia guairi: 
folia. Trans. Wis. Acad. Sei. Art. Let., XVI, p. 81, 1908. 


No. 499] NOTES AND LITERATURE 503 


indieation of the approaching mitosis. As the prophases of 
mitosis become evident the two polar struetures move away from 
the nuclear membrane, become much flattened, and spindle fibers 
develop in the region between the two. The polar structures 
then round up so that in the metaphase of mitosis they are 
irregularly rounded bodies at the poles of the spindle against 
which the ends of the spindle fibers press. During anaphase 
the chromatin of the daughter nuclei comes to lie closely against 
the surface of the rounded polar structures, and each daughter 
nucleus when fully formed is deeply indented or kidney-shaped 
in sections. The amount of starch decreases during the pro- 
phases, indicating that there is a consumption of starch at the 
time of the mitosis. The polar structures increase in size during 
telophase and remain at the side of the daughter nuclei until 
the above history is repeated with the next mitosis. 

In the spore mother-cells of Marsilia, Marquette has found 
evidence of polar organization at the time of synapsis. ` Fol- 
lowing the differentiation of the spore mother-cells there is a 
period of growth during which starch grains appear, first in a 
seattered arrangement, but soon in a specified region between the 
nucleus and the wall of the spore ease, a situation favorable for 
an interchange of metabolic movements between the nucleus and 
the surrounding tapetum. There is thus a polarity of the cell, 
which presently becomes more conspicuous by the changes char- 
acteristic of synapsis within the nucleus. The chromatic ma- 
terial during synapsis converges to a point on the nuclear mem- 
brane against which lies a nucleole, and the entire mass of con- 
tracted chromatin is directly opposite the assemblage of starch 
grains in the cytoplasm adjacent to the nucleus. The nucleus, 
then, during synapsis presents a definite polar side with its 
chromatin content contracted at a point opposite the assemblage 
of starch grains, and an antipolar side free from chromatic sub- 
stanee, where also the nuclear membrane appears much heavier 
than in the region of the synaptic mass. 

Fibers become conspicuous in the cytoplasm during synapsis, 
especially on the antipolar side of the nucleus, and these tend 
to become arranged in cone-shaped groups as the nucleus passes 
out of synapsis. There is at times a bipolar arrangement of 
the fibers, but later several well-defined poles are developed and 
a multipolar, stage results which is similar to the multipolar 
spindle characteristic of spore mother-cells. The cones of the 


504. THE AMERICAN NATURALIST [ Von. XLII 


multipolar spindle finally become grouped,to form a typical 
broad-poled bipolar spindle. During the mitosis the starch mass 
lies at the side of the spindle, but as telophase comes on, it grad- 
ually moves in between the two daughter nuclei, forming an 
irregular thin plate between the two. This starch plate sepa- 
rates the two spindles of the second mitosis which lie at various 
angles to one another. After the four granddaughter nuclei are 
formed the starch becomes distributed in about equal amounts 
to the four cells. The polar organization of the spore mother- 
cell of Marsilia, conspicuous at the time of synapsis, then dis- 
appears, according to Marquette, just before the formation of 
the first spindle. Marquette, however, seems inclined to believe 
that more careful study of multipolar stages in spindle forma- 
tion may establish a continuous polar organization throughout 
these mitoses. 

These investigations of Harper and Marquette are likely to 
stimulate further research upon the polarity of the plant cell, 
and a more eritical reinvestigation of favorable types where an 
isotropic or radial structure is believed to obtain. It may, 
nevertheless, be found that polarity will not depend in all cases 
upon the presence of permanent protoplasmic structures of 
sufficient size or morphological differentiation to rank as organs 
of the cell. There may be polarity at times without visible 
protoplasmic organization. It is probably very unusual for a 
cell to be so situated that its activities are expressed in a strictly 
radial fashion; there is rather certain to be an upper or lower, 
an inner or outer, or a one-sided relation to important environ- 
mental conditions, and these may be expected to develop meta- 
bolie centers, which, at times, may in their turn create such 
protoplasmic differentiation along an axis as to establish an 
evident polar organization of the protoplasm. 

Further evidence of polar organization in plant cells is pre- 
sented in the structure and development of the cilia forming 
organs, or blepharoplasts. Some recent research on these struc- 
tures will shortly be reviewed in the NATURALIST. 

RADLEY M. Davis. 


(No. 498 was issued on June 26, 1908.) 


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VOL. XLII, NO. 500 _ AUGUST, 1908 


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Vou. XLII August, 1908 No. 500 


THE MID-SUMMER BIRD LIFE OF ILLINOIS: A 
STATISTICAL STUDY? 


PROFESSOR S. A. FORBES 


UNIVERSITY OF ILLINOIS 


In the course of a statistical survey of the bird popula- 
tion of the State of Illinois, begun with a view to a better 
knowledge of the significance of birds in the economy of 
nature, two field observers, A. O. Gross and H. A. Ray, 
engaged in this work as assistants on the State Natural 
History Survey, spent virtually a month of the summer 
period of 1907 in each of the three principal sections of 
the state—June in southern, July in central, and August 
in northern, Illinois. Selecting in each section a locality 
typical for that part of the state, they made regular 
trips on foot in various directions and to various dis- 
tances, traveling always thirty yards apart, and noting as 
they went the species and numbers of all birds flushed by 
them on a strip fifty yards in width, including likewise 
those flying across this strip within a hundred yards to 
their front. They kept record, also, by means of me- 
chanical counters, of the distances traveled over each dis- 
tinguishable kind of area, commonly marked by the crop 
which is borne. ; 

The present paper is a report of a few of the more 
general results of a study of the materials thus brought 
together, illustrating the numbers and ecological distribu- 

1 Read before the Central Branch of the American Society of Zoologists, 
Chicago, January 2, 1908. 

505 


506 THE AMERICAN NATURALIST . [Vou XLII 


tion of the birds of Illinois during the relatively stable 
period of their summer residence—the time between the 
conclusion of the spring migration and the beginning of 
the fall movement to the southward. It is a period of 
breeding and steady habitation for our most permanent 
and characteristic bird population, and will best help us 
to an understanding of the main normal ecological signif- 
icance of Illinois birds. 


THE AREA OF OBSERVATION 

The total distance traveled by my observers on these 
various mid-summer trips was 428 miles (omitting frac- 
tions), of which 141 miles was in southern Illinois, 112 in 
central, and 175 in northern. The total area covered by 
this strict census of the bird population was a trifle over 
12 square miles, or 7,693.5 acres—33 per cent. of this 
acreage being in the southern, 26 per cent. in the central, 
and 41 per cent. in the northern, part of the state—or 
approximately a third of this area in southern, a fourth in 
central, and two fifths in northern, Illinois. The field 
observations began in the south June 4, and ended at the 
north August 23, with the idea of avoiding, so far as 
possible, by this order of progress, differences due to 
different seasonal conditions. It was not possible, of 
course, to eliminate these wholly, with only one pair of 
observers; and it will tax our ingenuity, and sometimes 
perhaps overtax it, to detect these differences and to dis- 
tinguish them from those due to mere difference of lati- 
tude and of climate corresponding. 

The total surface on which these precise mid-summer 
observations were made was 1/4,720 part of the whole 
state, and the question at once arises, Was this area suf- 
ficient to give these results any general value for the state 
at large, and, if so, how may we be sure of it? There is, 
I believe, no mathematical method of determining the 
sufficiency of these data for generalization purposes, and 
I know of no test at present applicable except that of the 
general consistency and reasonableness of the totals, 


No. 500] MID-SUMMER BIRD LIFE OF ILLINOIS 507 


averages and ratios, for the different districts and sea- 
sons, the presence or absence of which each can readily 
see for himself as this discussion proceeds. If the data 
of observation are insufficient for the uses made of them, 
there will be a random variability and inexplicable 
irregularity in my statistical summaries which we shall 
not fail to notice. 


GENERAL PRODUCT oF THE SuRVEY 

Gross and Ray identified during the summer, on the 
territory covered by their data, 7,740 birds, belonging to 
85 species. This is at the rate of 645 birds per square 
mile, or almost precisely 1 per acre, including the so- 
called English sparrow. If we omit the 1,414 interloping 
English sparrows observed—which is a little more than 
18 per cent. of the entire number of birds—we have 
remaining 527 native birds to the square mile. The total 
for Illinois,? on this basis, is 30,750,000 native birds and 
5,536,000 English sparrows, or approximately 14 summer 
resident birds to each person in this state living in the 
country or in towns of less than 25,000 inhabitants. 

Of the 85 species represented by the 7,740 birds 
recognized on these trips, the 21 most abundant species 
were represented by 6,596 birds. That is to say, 85 per 
cent. of the birds belonged to 25 per cent. of the species. 
The 21 more abundant species numbered, taken together, 
550 to the square mile, and the 64 less abundant species, 
taken together, numbered 95 birds to the square mile, or 
1 to every 63 acres. The latter species are evidently 
negligible as general factors in the ecological system, and 
attention need be given, in discussing the birds of the 
state as a whole, only to the 21 species common enough 
to produce some appreciable general effect. Given in the 
order of their abundance they are as follows: 

2 A combination of the averages for the three sections of the state, com- 
puted separately, the data for the sections being differently weighted to 
compensate for differences in area. 


508 THE AMERICAN NATURALIST [Vou. XLII 


A.O. U. Nos. | Bird | No. Observed Per Cent. 

X English sparrow | 1,414 18.4 
501 Meadow-lark 1,025 13.2 
511b Tod grece 900 11.6 
316 Mourn — 461 6. 

604 ickciss 393 5.1 
498 e ir blackbird 347 4.4 
474b Prairie horned lark 296 3.8 
412 Flicker 197 6 
761 Robin 194 2.5 
563 Field-sparr 186 2.4 
529 American soldi 158 2. 

444 ingbird | 126 8 
494 Bobolink 119 1.5 
546 Grasshopper sparrow 110 1.4 
705 Brown thrasher 104 1.3 
495 Cowbird 102 1.3 
406 Red-headed woodpecker 99 1.3 
613 Barn-swallow 96 1.2 
289 uail 91 1.2 
261 Bartramian BE 89 Xl 
488 Crow 89 i 

6,596 85.2. 


VARIATION WITH LATITUDE 

The English sparrow decreases in abundance from 
north to south, from 147 to the square mile in northern to 
113 in central, and 82 in southern, Illinois. One hundred 
sparrows in the northern part of the state are thus rep- 
resented by 77 in the central and 56 in the southern part.* 
The native summer residents, on the other hand, increase 
in numbers from north to south, the birds per square mile 
being 464, 537 and 600 for nothern, central and southern 
Illinois, respectively. That is, 100 native birds in 
northern Illinois were represented in mid-summer by 116 
in central and 129 in southern Illinois. The decrease in 
English sparrows from north to south is not sufficient to 
offset the increase in the native species, the total numbers 
per square mile for all summer birds in the three sections 
of the state being 610, 650 and 682—or 100 birds in 
northern for 107 in central and 112 in southern Illinois. 

This same gradation was much more pronounced in the 
record of the winter residents. From the last of Novem- 

3 Since the above was written, my attention has been called, by Dr. Hans 


Gadow, to the fact that in Europe also this sparrow diminishes in number 
southward. 


No. 500] MID-SUMMER BIRD LIFE OF ILLINOIS 509 


ber to March 15, birds averaged 384 to the square mile in 
northern Illinois; from December 23 to March 21, 582 to 
the mile in central Illinois; and from February 6 to 
February 21, 832 to the mile in southern Illinois, numbers 
related to each other as 100, 151 and 217. Indeed, we 
find birds more abundant in extreme southern Illinois in 
the mid-winter period of 1906-07 than in the mid-summer 
period of 1907, averaging at the rate of 122 birds in the 
former season to each hundred in the latter. 

If we take into account the numbers for the whole year, — 
there are, for every hundred birds in the northern part 
of the state, 133 for central and 181 for southern Illinois. 


BIRDS BY SECTIONS 


| Northern Illinois | Central Illinois | Southern Illinois 

Summer : | | 

Native | 100 116 | 129 

Sparrows | 77 | 56 

All birds | 100 107 112 
Winter: | 

Native | 100 170 292 

parrow 100 65 

All birds 100 151 217 
Whole year: | 

All birds 100 ' 133 181 


The bobolink was a distinctively northern bird, occur- 
ring in the ratio of 24 to the square mile in northern 
Tllinois, and not at all in either of the other sections. The 
mocking-bird, on the other hand, was almost exclusively 
southern, being represented by 8 birds to the square mile 
in the southern section, by only 1 specimen seen in cen- 
tral Illinois, and not at all in the northern part of the 
state. 

MıīcratTron WAVES 

In a paper published last April under the title ‘‘An 
Ornithological Cross-section of Illinois in Autumn,” 4 I 
. gave the data and results of a trip across central Illinois 
made by Gross and Ray during the fall of 1906. A com- 
parison of the general average of the bird population, 

‘Bull. Il. State Lab. Nat. Hist., Vol. VII, art. 9. 


510 THE AMERICAN NATURALIST [Von. XLII 


determined from the data of this trip for the period of 
the fall migrations, with the mid-summer average for 
the same section of the state, as determined last July, 
shows an interesting difference which leads us to con- 
sider the effect of the autumnal movement to the south on 
the numbers of the local bird population. On the above 
trip across the state, made between August 28 and 
October 17, 1906, a general average of 579 native birds to 
the square mile was found, while the corresponding mid- 
summer average for the present year is 537 native birds 
to the square mile—a difference of 42 birds to the mile, or 
nearly 8 per cent., in favor of the fall population. 


Native BIRDS PER SQUARE MILE, Faun (1906), Summer (1907) 


Migrant Resident Total 
Summer 537 537 
Fall 98 481 579 
Difference +98 —56 +42 


Was this difference due to the fact that the fall migra- 
tion was in progress when last year’s observations were 
made? That is, does the migration movement begin first 
at the north and result in a local wave of increased num- 
bers, birds coming in from the north earlier and faster 
than the resident species leave for the south? It is 
possible to answer this question by reference to the data 
of the paper just cited. 

An analysis of the list of species identified on last 
year’s autumnal trip shows that 481 per square mile of 
these birds were summer residents, still remaining, and 
that 98 per square mile belonged to migrant species, on 
their way to the south. The summer residents still pres- 
ent in this autumnal period were thus 56 per square mile 
fewer than the resident birds of the present summer. 
That is, 56 summer residents for each square mile of . 
central Illinois had gone south, on an average, and 98 fall 
migrants had, on the other hand, come in to take their 
place, the difference between these numbers giving us 


No. 500] + MID-SUMMER BIRD LIFE OF ILLINOIS 511 


the excess of 42 birds per square mile of fall over summer. 
This temporary increase of 8 per cent. in autumn in the 
average number of our birds is thus evidence of a wave 
of condensation running southward in consequence of the 
earlier beginning and more rapid development at the 
north of the annual fall migration. 

This contrast of the number of the resident summer 
population with that of the fall migration period is still 
more clearly and strongly shown by a comparison of the 
totals of all our central Illinois observations in mid-sum- 
mer and in fall, respectively. These average 1.07 birds to 
the acre for the period from July 9 to September 21, and 
2.31 per acre for the interval between the 1st and the 
26th of October. That is, more than twice as many birds 
per acre were seen in October of this year as in July, 
August and September. 

The data of the spring migration of 1907 are unsatis- 
factory owing to the extraordinary character of the sea- 
son, and the consequent repeated interruption and remark- 
able prolongation of the movement. Nevertheless, they 
indicate a larger population during the early part, at 
least, of this migration period also than either before or 
after it. A trip down the eastern side of the state from 
Cook to White county, begun March 26 and ending April 
11, gave an average of 1.34 birds to the acre—a number to 
be compared with our mid-summer average for the whole 
state, which is 1.03. That is, the average early spring 
population of this exceptional year was 30 per cent. 
greater than the average of the summer following. On 
the other hand, a trip across central Illinois between 
April 20 and May 29, still within the migration period, 
gave us, for 51/3 square miles of area, an average of only 
89 per acre—less than even the mid-winter average of 
91 for the same part of the state. . 

VEGETATION oF THE [NSPECTION AREA 


As a basis for a more precise account of the distribu- 
tion of birds as a whole and of the more important 


512 THE AMERICAN NATURALIST [Vou. XLII 


species, it will be necessary to consider the vegetable 
covering of the soil, since there is little else in Illinois by 
which different portions of its area may be distinguished. 
The territory traversed by my observers, it need hardly 
be said, was almost wholly under cultivation. Excluding 
only forests in which the trees were too high, or the 
undergrowth was too dense, to permit a full and accurate 
census of the birds, the territory reported upon was 
chosen wholly at random, and the total for each division 
of the state seems sufficient to give us, with the exception 
just mentioned, a fair sample of its crops and surface 
conditions. The areas from which all the birds were 
determined were 3,172 acres for northern Illinois, 2,117 
acres for central, and 2,504 acres for southern. 

In the upper third of the state, 95 per cent. of the 
surface was in corn, small grain and grass—31 per cent. in 
corn, 27 per cent. in small grain (nearly all of it oats) 
and 37 per cent. in the pasture and meadow crops, about 
equally in each. In the central region the area in corn 
rises to 46 per cent. of the whole, that in small grains was 
about 26 per cent. (again nearly all oats) and that in the 
forage crops was 27 per cent. (the pasture lands nearly 
twice as extensive as the meadows) —a total of 99 per 
cent. of the area examined which was devoted to these 
great farm crops. In the lower third of Illinois only 23 
per cent. of the land was in corn, an almost equal area 
(21 per cent.) was in small grain—more than half of it 
wheat—and 44 per cent. was in grass, clover and similar 
forage plants, rather equally divided between pastures 
and meadows. That is to say, the areas in corn and 
small grains were nearly the same, and these together 
were barely equal to the meadows and pastures. The 


Crop AREAS. Perr CENT., 1907 


Northern Illinois Central Illinois Southern Illinois 
Corn 31 46 23 
Grain 27 26 21 


rass $7 44 
Miscellaneous 5 1 12 


No. 500] MID-SUMMER BIRD LIFE OF ILLINOIS 513 


total in all these crops was 88 per cent. of the area in- 
spected, the remaining 12 per cent. covering the orchards, 
the more open woods, the waste and untilled lands, and a 
few additional minor items. 


Numsers or BIRDS BY Crops 
Tllinois is still a prairie state in the predominance of 
birds which prefer a grassy turf as, an abiding place. 


CROP AREAS AND BIRDS 


Almost exactly half of those recorded for the state last 
summer were from pastures and meadows, although the 


514 THE AMERICAN NATURALIST (Vou. XLII 


total acreage in these lands was but 36 per cent. of the 
entire area inspected. These figures are equivalent to a 
density ratio on pastures and meadows of 1.39 for all the 
birds of the state Corn is an exotic crop in Illinois, 
and birds were only about a third as abundant in corn 
fields as in grass lands, while in small grains they were 
nearly twice as abundant as in corn. The acreage in 
these crops was such that 15 per cent. of all the birds of 
the season were found in corn fields and 22 per cent. were 
in small grain. In orchards they averaged 4} times as 
numerous to the unit of area as in fields of grain, 2,471 
to the square mile—giving a density ratio of 3.84; but the 
acreage in orchards from which the birds were identified 
was so small that all the orchard birds together amount 
to only 2 per cent. of the whole number observed. Among 
native trees and shrubbery, birds were much less abun- 
dant than among fruit trees, and the density ratio for 
these situations was about 2.25. 

By way of further illustration of the application of this 
quantitative method to the subject of local distribution, I 
will present some of the more pronounced results for one 
species of bird throughout its range in summer, and for 
one kind of crop area as visited or inhabited by mid- 
summer birds. 

THE MEADOW-LARK 

One thousand and twenty-five meadow-larks were iden- 
tified by my observers in their work on the summer resi- 
dents of the state, an average of 85 to the square mile 
for the whole area traversed by them. As these birds 
were unequally distributed, never occurring, for example, 
in woodlands or among shrubbery, their numbers rose in 
some situations far above this general average, amount- 
ing to 266 to the square mile in stubble, 205 in meadows, 
160 on untilled lands, 143.5 in pastures, and 131 on waste 
lands, and falling to 10 to the square mile in fields of 
Corn. 

ë That is, taking an average density of the bird population for the whole 
area of the state as 1, the density in pastures and meadows only is 1.39 


No. 500] MID-SUMMER BIRD LIFE OF ILLINOIS 515 


MEADOW-LARKS PER SQUARE MILE. SUMMER, 1907 


PUTED e 1 see a sc sais Geen Melee Reo Cars cook te E 266 
MORGOWS: ocres ei ees oe Ve ek eee vik s ees 205 
BaUOw or. ere es ee ree ee oe ei ee CEN ers va 160 
PRSbUTOS ES OS ae ee Pe se 143.5 
AL TI EIRA EA vals See eee ea EE eee wedi + bec ess 131 
CORDS yee wes gab arse a NG ree a PECL eos so Bc cee 10 
WOGUR> E: tte Oy puree Ce Eee eee Ses su bes wives as 
ATU DS re Pre eee sea ea Be a ks save se eee — 
Btate se raoe ek N Vc nN a eS re iN 85 


They varied also in abundance, in a very interesting 
way, from the north to the south. One hundred of them 
in northern Illinois were represented by 175 in central 
and by 215 in southern Illinois. This variation was evi- 
dently independent of any difference in the extent of 
surface covered by the kinds of vegetation which they 
most prefer, since the ratio of pasture, meadow, waste 
and untilled lands taken together was considerably less 
for central than for northern Illinois, although the 
meadow-larks were 75 per cent. more numerous; and it 
was only a fourth greater for southern Illinois than for 
northern, although the meadow-larks were more than 
twice as abundant. The cause of the greater numbers 
southward, so far as I can see, can be accounted for only 
rather vaguely as climatic. 

Much more difficult of even general or hypothetical ex- 
planation is a curious difference in the observed abun- 
dance of meadow-larks in pastures and meadows re- 
spectively, in the three divisions of the state. In northern 
Illinois there’ were 87 larks per square mile in pastures 
to 129 in meadows; in southern Illinois there were 125 
in pastures to 297 in meadows; while in central Illinois 
this relation was reversed, the number in pastures being 
274 to the mile, and that in meadows 189. That is, while 
100 pasture birds were represented in northern Tllinois 
by 148 in meadows, and in southern Illinois by 242, in 
central Illinois they were represented by only 69. Since 
the southern Illinois observations were made in June, 
those for central Illinois in July and those for northern 


516 THE AMERICAN NATURALIST [Vou. XLII 


Illinois in August, one naturally looks to differences in 
season, in the advancement of the crops, or in agricultural 
operations as related to the haunts and habits of these 
birds, for an explanation of their apparent shift from 
meadows to pastures in July in central Illinois, and a 
seemingly plausible explanation is suggested by the fact 
that haying was mainly done during July in the central 
part of the state, but was not yet fairly begun in southern 
Illinois in June and was nearly over in northern Illinois 
in August. 


PASTURE BIRDS PER SQUARE MILE. SUMMER, 1907 
Meadow-larks 


| Northern Ilinois | Central Illinois | Southern Illinois 


Pasture | 87 | 274 125 
Meadow | 129 | 189 297 


Other Pasture Birds 


Pasture 50 54 120 
Meadow 200 131 371 


If, however, the meadow-larks were disturbed to this 
extent by the operations of making and saving the hay 
crop, one would expect to find the other distinctively 
meadow birds similarly affected—a supposition which is 
not borne out by the facts of our record. Besides the 
meadow-larks, there were five common species more abun- 
dant in meadows in one or another section of the state 
than in any other important situation; namely, the red- 
winged blackbird, the purple grackle, the vesper-sparrow, 
the grasshopper sparrow, and the dickcissel. Each of 
these species was, moreover, more abundant in meadows 
than in pastures in each section of the state—in central 
Illinois as well as in the other two—excepting only the 
grackle in southern Illinois. Taking all five of these 
birds together, there were in northern Illinois 200 to the 
square mile in meadows and 50 in pastures, in central 
Illinois 131 and 54, respectively, and in southern Illinois 
371 and 120. In other words, for each hundred of these 


No. 500] MID-SUMMER BIRD LIFE OF ILLINOIS 517 


five kinds of birds in meadows, there were, in the northern 
section, 25 of them in pastures, in the central section 41, 
and in the southern section 32. The cause of this ap- 
parent change in the preference of the meadow-larks of 
central Illinois seems, therefore, something peculiar to 
themselves, and is still to seek. 


BIRDS oF THE PASTURES 

The birds of a given situation may be discussed from 
two quite different standpoints, both interesting and 
pertinent, and both really necessary to a complete under- 
standing of the facts. We may consider the members of 
an assemblage of species there with first reference to their 
relative importance to the situation itself—with refer- 
ence, that is, to their comparative numbers, or to the 
nature and effect of their activities; or we may consider 
the situation with first reference to its relative importance 
in the economy and life of each species of bird which in- 
habits or visits it. If this situation is woodland, for 
example, a bird found only in forests might, if a com- 
paratively rare species, have very little importanee— 
might produce very little effect in the situation because 
of its infrequent occurrence there, while to the species 
itself the forest situation would be all-important, as the 
sole place of its habitation. Its own significance in 
forests might be easily overbalanced by a very abundant 
species which should visit woodlands only occasionally, 
but whose average numbers there might be twice or 
thrice as large to the unit of area and time as those of the 
less abundant species inhabiting forests exclusively. 
Time will not permit me to illustrate this division of my 
topic from both these points of view, and I will limit 
myself to a few words in conclusion on the pasture birds 
as a group and on some of the more prominent pasture 
species with reference to their importance in pastures. 

Pasture lands were the preferred resort of our most 
abundant mid-summer birds. That is, more birds were 
seen in pastures than in any other of the larger crop areas 


518 THE AMERICAN NATURALIST [Vou. XLII 


of the state—2,107 in that situation as against 1,814 in 
meadows, 1,667 in fields of small grain, and 1,169 in fields 
of corn. Indeed, 27.2 per cent. of all the mid-summer 
birds determined by my observers were seen in pastures, 
23.4 per cent. in meadows, 21.5 per cent. in small grain, 
and 15.1 per cent. in corn. The area in pastures was 
larger than that in meadows, however, and on this ac- 
count, if we consider the number of birds per square mile, 
we must change this order of precedence. With a general 
mid-summer average of 645 birds to the square mile for 
the whole state, we have 920 to the mile for meadows, 878 
for pastures, 962 for small grain, and 300 for corn. Or, 
if we take the number per square mile for the entire 
state as 1, 1.43 will be the density ratio for meadows, 1.36 
for pastures, .87 for grain fields, and .47 for corn fields. 


SUMMER BIRDS IN Crops, 1907 


Numbers Ratio Per Square Mile Densities 


Pastures 2,107 27.2 ` 878 1.43 
Meadows 1,814 23.4 920 1.36 

i 1,667 21.5 562 87 
Corn 1,169 15.1 300 AT 
Other 983 12.8 


Looking to the composition in species of this mid-sum- 
mer pasture population, we find that more than half the 
summer resident birds of Illinois pastures belong to five 
species—the English sparrow, the meadow-lark, the crow- 
blackbird, the horned lark and the field-sparrow, rela- 
tively abundant in the order named; and this statement 
is almost as true of the three sections of the state as it is 
of the state as a whole. Comprising nearly 53 per cent. 
of the pasture birds of the entire state, these five species 
made 49 per cent. of those of northern Illinois, 61 per 
cent. of those of central Illinois, and 47.5 per cent. of 
those of southern Illinois. Indeed, the first four of these 
species were the most abundant pasture birds of the whole 
state for the whole year, occurring there in the following 
numbers: English sparrow, 1,394; crow-blackbird, 696; 
meadow-lark, 686; horned lark, 603; and field-sparrow, 


No. 500] MID-SUMMER BIRD LIFE OF ILLINOIS 519 


230. These are consequently our most typical pasture 
birds. In the pastures of the state at large the English 
sparrow was the most abundant species, making 20 per 
cent. of all the birds seen in pastures during the summer 
months, and the meadow-lark was nearly as common, 
making 17 per cent. of these birds. The meadow-lark 
was, indeed, the most abundant pasture bird in both 
southern and central Illinois, the sparrow surpassing it 
only in the northern division of the state. The horned 
lark, on the other hand, was second in northern Iilinois, 
but tenth in both central and southern Illinois, and fourth 
for the state as a whole. The crow-blackbird was third 
on the list for the whole state, fourth for southern Illinois, 
third for central, and sixth for northern Illinois. 

Ten species comprised more than two thirds of the 
pasture birds of the state, and these same ten species 
made 63 per cent. of the birds of northern Illinois 
pastures, 80 per cent. of those of central Illinois, and 64 
per cent. of those of southern Illinois. Besides the five 
species already mentioned, these were the flicker, the 
robin, the mourning-dove, the red-headed woodpecker, 
and the red-winged blackbird. : 

One general impression made by this preliminary ex- 
amination of the present bird population of the State of 
Illinois is that of a remarkable flexibility and tenacity of 
the associate and ecological relationships of birds in the 
face of revolutionary changes in their environment. 
Apart from the results of the introduction of the English 
sparrow, and the direct destruction of game birds and 
birds of prey, the main effect of human occupation seems 
to have been the withdrawal of most of the prairie birds 
from the area devoted to Indian corn, and their concentra- 
tion in pastures, meadows, and fields of small grain— 
situations which most nearly resemble their original 
habitat. : 


THE LIFE CYCLE OF PARAMECIUM WHEN 
SUBJECTED TO A VARIED 
ENVIRONMENT 


DR. LORANDE LOSS WOODRUFF 


YALE UNIVERSITY 


Strupies on the life cycle of Paramecium aurelia. (cau- 
datum) have been made by several investigators, the most 
extensive work being that of Calkins. As is well known, 
his results showed that when Paramecium was bred con- 
tinually in a culture medium of hay infusion, it passed 
through more or less regular cyclical variations in general 
vitality as measured by the division-rate. The marked 
periodical depression periods occurred at about six-month 
intervals and unless the organisms were ‘‘stimulated’’ at 
this time the culture died’ out. Minor depressions oc- 
curred about every three months, but from these recovery 
was autonomous. Joukowsky? and Simpson,’? however, 
apparently found that certain cultures of this organism 
died out after being but a short time under culture condi- 
tions. 

A constant culture medium is an important condition 
for the study of the consecutive phases of vitality, and of 
the effect of stimuli on the organism, but it is of interest, 
however, in the light of the results obtained by this 
method to determine the character of the life cycle of 
Paramecium when subjected to a varied environment. 
It is possible, of course, that some element is lacking in 

* Calkins, G. N. Studies on the Life History of Protozoa. I, The Life 
Cycle of Paramecium caudatum. Archiv f. Entwk., XV, 1, 1902. IV, Death 
of the A Series. Journal Exper. Zool., I, 3, 1904. 

? Joukowsky, D. Beiträge zur Frage nach den Bedingungen der Ver- 
mehrung und des Eintrittes der Konjugation bei den Ciliaten. Verh. Nat. 
Med. Ver. Heidelberg, XXVI, 1898. 

*Simpson, J. Y. Observations on Binary Fission in the Life History 
of Ciliata. Proc. Royal Society Edinb., XXIII, 1901. 

520 


No. 500] LIFE CYCLE OF PARAMECIUM 521 


a constant culture medium of hay infusion which is 
essential to the continued life of the organism, and that 
depression effects which appear more or less regularly 
are due, in part, to a process of slow starvation—rather 
than to a loss of the power of assimilation. Recovery 
from these periods is effected by various stimuli (beef 
extract, etc.), because the lacking factor, or factors, is 
thereby supplied. Calkins himself points out the marked 
similarity of the morphological changes which he obtained 
in the earlier cycles of his Paramecium cultures with those 
found by Wallengren‘* to occur in Paramecia which had 
been intentionally starved. I have also called attention 
to this similarity in discussing the life cycle of various 
hypotrichous infusoria and have suggested that the effect 
of such stimuli as beef extract, etc., may be essentially 
that of concentrated nutrition.” 

In connection with some experiments on the effect of 
various stimuli on the life cycle of infusoria,® I have had 
oceasion to carry a culture of Paramecium for over a 
year, and the data derived from this work are believed to 
throw some light on the effect of a varied environment on 
the life history of this organism. 

On May 1, 1907, a ‘‘wild’’? Paramecium was isolated 
from a laboratory aquarium and placed on a depression 
slide in five drops of hay infusion. When this animal 
had divided twice, the four resulting individuals were 
isolated on separate slides, and in this manner were 
started the four lines, I-a, I-b, I-e and I-d, which compose 
this culture? The culture has been continued by the 
isolation of an individual from each of these lines almost 
daily throughout the life of the culture up to the present 
time (May 6, 1908) and a record has been kept of the 

t Wallengren, H. Tnanitionserscheinungen der Zelle. Zeit. f. allg. 
Physiologie, I, 1, 1901. 

5 Woodruff, L. L. An Experimental Study on the Life History of Hypo- 
trichous Infusoria. Journal Exper. Zool., II, 4, 1905. 

Woodruff, L. L. Effects of Alcohol on the Life Cycle of Infusoria. 
Biol. Bull., XV, 2, 1908. 
1 Further details in regard to the technique are given in previous papers. 


[Vou. XLII 


THE AMERICAN NATURALIST 


522 


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No. 500] LIFE CYCLE OF PARAMECIUM JLo 


daily bipartitions of each line. The following curve 
represents graphically the average rate of division of the 
four lines of the culture, and this again averaged for ten- 
day periods. 

The culture was carried on at the Thompson Biological 
Laboratory .of Williams College, Williamstown, Mass., 
during May and June, 1907; at the Marine Biological 
Laboratory, Woods Holl, Mass., during July and August, 
1907; and at the Sheffield Biological Laboratory of Yale 
University, New Haven, Conn., from September, 1907, to 
the present time, May, 1908. 

The culture medium during the earlier months of the 
work consisted of hay or grass infusion. But, except 
during periods in which the culture was employed as a 
control for certain experiments, the infusion was made 
with hay or grass from various localities and different 
proportions of hay and water were used almost daily. 
Water from various sources was employed. In every 
ease the temperature of the infusion was raised to the 
boiling point, and then allowed to attain the temperature 
of the laboratory before being used. In some cases the 
infusion was made fresh daily, in other cases it was 
allowed to stand twenty-four hours before being used. 

Beginning in February, 1908, a much more varied cul- 
ture medium was employed. It was found that Para- 
mecium can exist in nearly any infusion which may be 
made from materials collected in ponds and swamps, and 
accordingly, in the hope of supplying as far as possible all 
the elements which may be encountered in the ‘‘normal’’ 
habitat of the organism, water was taken from ponds, 
laboratory aquaria, etc., together with its animal and 
plant life. In other words, no definite method was em- 
ployed in selecting the material, but it was simply col- 
lected at random from many sources, thoroughly boiled, 
and then used. This culture medium affords a striking 
contrast to that employed by Calkins, which he described 
thus, ‘‘The hay infusion was made every day, the same 
amount of hay and water being taken each time and 


524 THE AMERICAN NATURALIST  [Vor. XLII 


raised to the boiling point. This method was never 
varied during the entire period of the cultures and the 
salt content of the water, as shown by weekly analyses, 
did not vary beyond a very slight fraction of one part 
to one hundred thousand.’’ 

The only condition present in the life of this culture 
which could not be encountered by a wild Paramecium 
was the boiled condition of the culture medium, but this 
was essential in the experiments in order to prevent the 
introduction of an encysted or active wild individual into 
the culture. 

The objection might be made that the environment was 
changed too frequently and too greatly to afford natural 
conditions. But, if the hundreds of millions of wild in- 
dividuals which are derived from a single wild Para- 
mecium are considered, and if the environment of any 
four lines of descent of four individuals existing at the 
end of twelve months in the wild state is taken into ac- 
count, it will be readily appreciated that the surviving 
organisms have probably experienced far more changes 
of medium than have the four lines of the culture under 
consideration. It may be that only those individuals 
which have encountered varied conditions have survived 
without resorting to conjugation. 

It is obvious, indeed, that all the variations in environ- 
ment which may be experienced by a wild Paramecium 
have not been supplied; for in a pond considerable 
changes of temperature occur during the year, and 
periods of rest by encystment or lack of food are afforded. 
It is believed, however, that the conditions under which 
this culture has been carried approach nearer to those 
encountered by the majority of wild individuals than has 
been the case in previous investigations. 

A glance at the plotted curve of the life history shows 
that at no ten-day period during the life of the culture up 
to the present time has the average rate of division of the 
culture fallen as low as one division in two days, the 
nearest approach to this rate being attained at period 


No. 500] LIFE CYCLE OF PARAMECIUM 525 


twenty-two in December, 1907, when the culture was sub- 
jected to a particularly uniform culture medium. The 
highest rate of division so far attained occurred at 
period ten in July, 1907. The average rate of division 
for the entire year is obviously considerably above one 
division per day, the organisms being in the 465th genera- 
tion on May 6, 1908. That this is not the maximum rate 
of division of which the culture is capable is shown by 
the fact that a culture isolated line by line from the one 
under consideration and treated daily for six months with 
alcohol is at the same date in the 505th generation. 

The major fluctuations in the division rate which have 
occurred in the life of this culture are all ‘‘rhythms”’ 
(using this term in the sense in which I employed it in 
discussing the life history of Oxytricha) and so far no 
‘feycle’’ has been completed. Calkins in his earlier 
papers on Paramecium believed the cycle to be of three 
months’ duration, agreeing in this regard with certain of 
the earlier investigators on this form. In his last paper 
on the subject, however, as has been noted, he interpreted 
the tri-monthly fluctuations as simply minor changes from 
which recovery was autonomous and regarded the cycle as 
the larger semi-annual fluctuations, recovery from which 
was only brought about by stimuli. I have previously in- 
terpreted these trimonthly depressions as rhythms and 
the results obtained from this culture would seem to show 
that the semi-annual cycles of Calkins are also merely 
rhythms—recovery from which was not autonomous under 
the conditions of a constant environment. This culture 
shows that the cycle of Paramecium under a varied 
environment may be considerably over a year in duration, 
since the culture at present shows no sign of waning 
vitality. | 

This suggests the much-discussed question as to whether 
the protozoa are potentially immortal, and the rôle of 
conjugation in the life history. Up to the present time 
there has been no tendency among the individuals of this 
culture to conjugate, although in the ‘‘stock’’ cultures, 


526 THE AMERICAN NATURALIST (Vou. XLII 


comprising individuals left over after the daily isolations, 
there has been every opportunity for its occurrence. Of 
course there has been no possibility of conjugation in the 
four direct lines of the culture on account of the daily 
isolations. This result agrees with that which I obtained 
with my cultures of various hypotrichous forms—and I 
believe it suggests strongly that conjugation must be re- 
garded as a more or less variable phenomenon which 
occurs in the life history when conditions are adverse for 
the normal life of the organism, and which is not neces- 
sary under the conditions of a varied environment. I 
believe it is customary to regard conjugation as of far 
more frequent occurrence than it actually is in the life 
history of ‘‘wild’’ individuals, because it is brought to the 
attention in laboratory cultures and ‘‘hay infusions’’ 
which pass through a series of changes—changes which 
inevitably bring about conditions unfavorable to the con- 
tinued reproduction of the organisms, and which are com- 
pensated for by conjugation. 

No period of marked physiological depression is indi- 
cated by the division-rate of this culture during the first 
year of its life; but well-defined morphological changes 
have occurred. These cytological variations, chiefly 
nuclear, demand further study. It is evident, however, 
that the relation of the rate of division to the so-called 
“‘normal’’ condition of the nuclear apparatus of Para- 
mecium is not substantiated by this culture, as profound 
nuclear changes apparently do not affect the rate of divi- 
sion. I believe from a study of this culture and “wild” 
cultures in large laboratory aquaria, that various nuclear 
changes which are not at present. recognized occur 
normally in the life history of Paramecium, and that 
possibly when conjugation between two individuals is 
prevented, either under the conditions of culture or in the 
“‘wild’’ state, a rearrangement of the nuclear apparatus 
is resorted to which may be analogous to endogamy, or 
conjugation of nuclei within the original cell. 


PLACOBDELLA PEDICULATA n. sp.! 


ERNEST E. HEMINGWAY 


UNIVERSITY OF MINNESOTA 


In the summer of 1889, while at Lake Pepin super- 
intending the zoological work of the Geological and 
Natural History Survey of Minnesota, Professor Nach- 
trieb found that some of the sheepsheads (Aplodinotus 
grunniens) which were being seined from the lake in 
large numbers by the local fishermen had a large parasitic 
leech fastened to the isthmus or shoulder under the gill 
cover. Three of these leeches were collected at that time, 
with portions of the fish showing the place and manner of 
attachment. One of these specimens was later sent to 
Professor J. Perey Moore, who found it to be a new 
species of Placobdella and suggested the specific name 
. pediculata. All the specimens originally collected were 
adults, gorged with blood, and greatly modified in form 
from the usual Placobdella types by their close parasitic 
habit; so that, in some parts, annulation and many other 
external features had been entirely obliterated. It was 
seen at once that to determine these features younger and 
better-preserved specimens must be obtained. Accord- 
ingly, during the first part of September, 1903, I spent 
several days with the fishermen around the head of Lake 
Pepin examining fish for this leech. During this time 
I examined many hundreds of fish and succeeded in ob- 
taining three small specimens, none of which were over 
a centimeter in length. 


Hasits 
Placobdella pediculata appears to be a true fish para- 
site, having been found only in the gill chamber of the 
* From the creas of the Department of Animal Biology, the Uni- 
versity of Minnesota 


527 


528 THE AMERICAN NATURALIST (Vot. XLII 


fresh-water sheepshead, the posterior sucker of the leech 
being deeply imbedded in the side of the isthmus or 
shoulder. In the case of young leeches which have not 
been long attached, the depression caused by the pos- 
terior sucker is comparatively shallow, being a mere ex- 
ternal depression in the inflamed tissues of the fish. As 
the attachment continues the inflamed tissues of the host 
grow up like a collar and close in around the leeches 
body in front of the sucker. This closing in of the in- 
flamed collar presses upon the body of the leech, narrows 
it to a slender peduncle in front of the sucker and in- 


Ci} 
eS 
WY 


Ss 
5 

KA 

Be 


Ape 
eS aA 
Š PSN 

gO eee 


The shoulder of a sheepshead with three depressions from which 
ave been removed and one of the depressions cut in two lengthwise. 


Fig. 1. 

the leeches h 
cidentally crowds the sucker down into the tissues of the 
fish, so that, in time, this depression may reach into the 
underlying muscles to a depth of half an inch or more 
and have an opening of about a quarter (or less) of an 
inch in diameter. The bottom of the depression has a 
larger diameter. Fig. 1 represents the positions of three 
depressions from which the leeches have been removed, 
and one of the depressions cut in two lengthwise. 

These leeches are capable of becoming greatly con- 
tracted, and when one is disturbed it draws back until it 
appears as a mere brownish pyriform knob which 
entirely covers the place of attachment. 


No. 500] PLACOBDELLA PEDICULATA 529 


The burying of the posterior segments in the tissues of 
the host has brought about an interesting structural 
change so that we find the anal opening shifted forward 
to a position between somites XXIII and XXIV instead 
of between somites XX VII and XXVIII, as in the other 
members of the genus. It is noticeable that, while the 
young leeches whose posterior portions are not yet 
deeply imbedded have the characteristic position of the 
anus (XXITI-XXIV), the outline of the posterior part 
of the body is still a regular curve showing none of the 
pedicular characteristics so pronounced in the older in- 
dividuals. The posterior sucker, however, is very 
strongly developed even in those not more than a centi- 
meter long. 

Practically nothing is known of this leech separate 
from its host, but it seems possible that a part of its 
existence may be spent elsewhere. During September, 
1903, I examined several thousand fish of this species. 
from Lake Pepin and found only three isolated leeches, 
each about a centimeter in length. The posterior sucker, 
while imbedded in the tissue, was not sunk in deeply and 
so had not produced the characteristic peduncle. They 
were evidently young ones which had recently attached 
themselves to their hosts and were gradually sinking the 
posterior sucker into the host’s flesh. As full grown 
specimens, deeply imbedded, were found in the same 
locality during August of 1899, at least some of the 
adults must remain with their hosts during the summer 
and probably throughout the year. 


DESCRIPTION” 

Like Placobdella parasitica and P. rugosa, this is a 
species of large size, though not quite equaling the largest 

? This description is based upon both young and large mature speci- 
mens gorged with blood. In view of unavoidable ‘delay in the publication 
of Professor Nachtrieb’s projected report on the leeches of Minnesota,. 
Professor Moore kindly consented to the free use of his description pre- 
pared for the systematic portion of the report here alluded to. I have 
retained the specific name suggested by Moore, though his description, being 
based upon a single large, gorged and much contracted specimen, was o: 
necessity somewhat incomplete. 


530 THE AMERICAN NATURALIST [Von XLII 


examples of the forms mentioned. It is more than 
usually contractile and therefore difficult to preserve in 
a suitable condition for study. The outline is very char- 
acteristically pyriform and strongly convex dorsally, as 
shown in the figures. But the most striking peculiarity 
is the attenuation of the posterior somites to form a 
narrow pedicel just in front of the posterior sucker, 
which consequently stands out freely in a most char- 
acteristic manner. The oral sucker has the same struc- 
ture as in P. parasitica. 


4 
Po m s5 A 
———— 

oS 


«ge 


Fie. 2. Lateral, dorsal and ventral views of a mature specimen gorged 
with blood. 


No trace of cutaneous papille can be detected, the skin 
being perfectly smooth. The segmental sensille and 
scattered sense organs are very indistinct. Eyes are 
very difficult to detect in the mature animals, but appear 
as small pigment masses at III-IV in the young. The 
annulation is essentially like that of P. parasitica except- 
ing the caudal peduncle and the generally simpler struc- 
ture of the corresponding somites of P. parasitica. 

Somites I and II contain each but one annulus. 
Somites ITI and IV are biannulate and V is biannulate 
dorsally, but ventrally the furrow fades away medially. 
VI is triamnulate above, but the furrow al—a2 is incom- 
plete below. Somites VII to XXIV are triannulate, but 


No. 500] PLACOBDELLA PEDICULATA 58l 


the furrow al—a2 is incomplete medially on the ventral 
side of both VII and VIII, and in most of the succeeding 
sonites is less marked than either a2-a3 or the inter- 
segmental furrows. In the anterior somites and to a 
less degree in the posterior, a3 is slightly longer than 
al or a2. The annulation of the post-anal somites, con- 
stituting the caudal peduncle, is irregular and somewhat 
puzzling on the older specimens, but is fairly distinct on 
the younger ones. Somite XXIV, which immediately 
succeeds the anus, is triannulate. Somites XXV, XXVI 
and XXVII are all biannulate, but al of somite XXV is 
partially divided and al of both XXVI and XXVII is 


3. Sketch of a young specimen showing somites I-XXVII, annuli and 
relative positions of the eye (e), proboscis (prob), esophageal gland (oeg), 
enlarged portion of the vas deferens communis (s$), ovary (ov), testes (T), vas 
deferens communis (vdc), intestine (int) and anus (an 


larger than a2. Neither annulus of XXVII is complete, 
al reaching only to the sides of the body and a2 not as 
far. The dise is composed of somites XXVIII to 
XXXIV. The accompanying Fig. 3 represents the 
arrangement of the furrows in a young animal. Somite 
XXIV is the last segment of the body proper and its 
posterior boundary forms in contracted specimens a fold 
which envelops the contiguous portion of the narrowed 
peduncle. The latter continues to narrow to the sucker, 
to the middle portion of which it is strongly attached for 
rather more than the posterior half. The posterior 
sucker is larger, circular and directed strongly ventrad. 
The nephridiopores are in the sensory annuli of somites 
VIII to XI and XII to XXII and are placed similarly 
to those of P. parasitica. 


532 THE AMERICAN NATURALIST [Von. XLII 


The mouth is very small and situated far forward near 
the anterior rim of the sucker in somite IT. As in related 
species, the proboscis is slender and the crop is provided 
with seven pairs of large cæca reaching nearly to the 
margins of the body. The ceca, however, are less deeply 
and finely divided than in P. parasitica, each of the first 
Six pairs exhibiting only two or three rather short lobes. 
The intestine reaches to the posterior part of somite 
XXIV or even beyond and then bends abruptly forward 
toward the dorsum as an extremely narrow rectum reach- 
ing to the minute anus situated at XXITI-XXIV. The 
forward curvature of the rectum and the anterior position 
of the anus are unique features in the family. The 
salivary glands are widely scattered through the an- 
terior two thirds of the body. On either side of the 
esophagus in somites X and XI lie a pair of compact 
esophageal glands which join the eeopnagie by a short 
duct in somite XT. 

The reproductive organs are eaii similar to those 
of P. parasitica. The male and female external orifices 
are situated at XI-XII and XIIa2-a3, respectively. Six 
pairs of testes are crowded between’ the bases of the gas- 
tric ceca. The large sperm sack and the ejaculatory duct 
of the vas deferens form a compact snarl in somite XII in 
the immediate neighborhood of the atrium. Nothing is 
known of the early stages of development. 


MARINE LABORATORIES, AND OUR ATLANTIC 
COAST 


DR. ALFRED G. MAYER 


MARINE LABORATORY OF THE CARNEGIE INSTITUTION, 
Dry TorruGas, FLA. 


We are fortunate above all civilized nations in having 
in the range of our Atlantic sea-board a unique diversity 
of conditions affecting marine life. The arctic current 
ereeps down the northern New England coast to Cape 
Cod, and during the winter the strong northeasterly winds 
drive its cold waters southward to the mouth of the 
Chesapeake. In summer, however, the southerly winds 
reverse these conditions, and the warm surface waters 
from -the Gulf stream are drifted upon the shores þe- 
tween Cape Hatteras and the southern side of Cape Cod. 

Another well-marked region is that between -Cape 
Hatteras and Cape Canaveral, Florida, where we find a 
very characteristic warm-water fauna, which is again 
distinct from that of the coral reef region of Florida, 
south of Miami. 

Thus, broadly speaking, there are four well-marked 
faunistic regions along our coast, and each affords its 
own peculiar problems for research. A mainly arctic 
fauna is found from northern Maine to Cape Cod, a 
transitional and seasonally fluctuating fauna from the. 
southern coast of New England to Cape Hatteras, crea- 
tures of a warm sea from Cape Hatteras to Cape Cana- 
veral, Florida, and a strictly tropical colony from Bis- 
cayne Bay, Florida, southward. 

The physical features of the coast itself are also most 
important in determining the character of the animals of 
the shore. Thus the rocky wave-worn ledges of the coast 
of Maine, the varied character of that of southern New 
England, the monotonous stretch of shifting sand be- 

533 


534 THE AMERICAN NATURALIST [Vou. XLII 


tween Sandy Hook and Cape Canaveral, and the coral 
reefs of Florida, have each their own peculiar fauna and 
impose their own limitations upon the diversity of animal 
life. A diversity which is accentuated by the fact that 
in Florida we find a tidal rise and fall of less than two 
whereas in northern Maine the diurnal range is more 
than thirty feet. 

Moreover, the relatively brackish and protected waters, 
such as those of Long Island, Pamlico and Albemarle 
Sounds, Chesapeake and Delaware Bays, and the tor- 
tuous estuaries and salt-water creeks of the Carolinas and 
northern Florida, have faune differing widely from those 
of the more richly endowed outer sea-beaches. 

It is therefore evident that in so far as research is con- 
cerned no one biological laboratory can grant facilities 
other than those limited by the conditions of its own 
locality. The purposes of research demand that we 
establish a series of stations at salient points from Maine 
to southern Florida. 

On the other hand, the successful prosecution of 
research demands that our youth be trained to its per- 
formance, and to this end it is essential that certain of 
the more centrally situated laboratories should devote 
some part of their energies to the giving of primary in- 
struction. 

Such instruction should, I believe, be given only in 
those laboratories which are placed near large centers 
affording the advantages of accessibility and diversity of 
intellectual interests. On the other hand, a certain re- 
moteness from the busy world and consequent freedom 
from interruption is peculiarly favorable to the conduct of 
research, and it is interesting to observe that the only 
laboratory, along our coast, devoted exclusively to re- 
search is placed upon the most inaccessible island along 
the entire range from Maine to Florida. 

At present we find one laboratory at South Harpswell, 
Casco Bay, Maine, a great center at Woods Holl, another 
at Cold Spring Harbor, in Long Island Sound, another 


No. 500] MARINE LABORATORIES 535 


at Beaufort, North Carolina, and one at the extreme 
westerly and southerly end of the Florida Keys. 

No laboratory has as yet been established along the in- 
teresting coast between Hatteras and Sandy Hook, with 
its peculiar transitional fauna; yet such situations as 
Cape May, or Linhaven, or Willoughby Harbors in Hamp- 
ton Roads, would afford a suitable site for such a station. 

It is not so remarkable that no laboratories have been 
established upon the inner shores of Delaware or Chesa- 
peake Bays, or at Pamlico or Albemarle Sounds, for in 
these brackish inland waters the fauna is but limited in 
comparison with the rich variety of forms to be found 
along the exposed sea-beaches. In future, indeed, we 
should endeavor to avoid the error which has, in places, 
been made of building our laboratories in situations from 
which the open water is not readily accessible at all times, 
for it is peculiarly true of every laboratory that the 
animals which afford the subjects of its most significant 
researches are invariably those which may be obtained in 
abundance in the near neighborhood of the station itself. 
It is, therefore, most desirable that the laboratory be 
placad-i in close proximity to the richest collecting grounds 
of the region. 

It is remarkable that so little effort has been made to 
properly install a laboratory for general instruction and 
research upon the coast of New England north of Cape 
Cod Bay. Yet here we find one of the most sharply dif- 
ferentiated of the faunistice divisions of our coast. The 
welfare of research in marine biology demands the ade- 
quate maintenance of such a station. 

Returning recently from a visit of half a year to 
various biological centers in Europe the writer has 
formed the impression that the scientific results which 
have been achieved by investigators in our marine 
laboratories have won the admiration of European 
students, while at home our intelligent publie is only 
beginning to awaken to the fact that they are worthy of 
respect. 


536. THE AMERICAN NATURALIST  [Vou. XLII 


In America, however, we may consider it fortunate that 
in order to win that form of recognition which leads to 
advancement in material as well as in intellectual well- 
being, it is necessary that our institutions of learning 
should attract the respectful interest of broad minded 
men of culture who are also leaders in the great affairs 
of the commercial world. Much may be learned by those 
desirous of furthering the already superior work of our 
laboratories, through a study of the methods of manage- 
ment of the great museums of New York City. Certain 
it is that the direction of any successful laboratory de- 
mands a two-fold capacity. On the one hand, we face a 
problem of expenditure and receipts, and on the other 
hand, a dependent but widely different problem of the 
scientific scope and aim of the institution. A neglect to 
attain to excellence of management from the purely com- 
mercial standpoint, must react unfavorably upon the 
ability of the institution to attain toward the realization 
of its proper ideals in scientific achievement. It appears 
to the writer that our institutions of learning which are 
dependent upon the public for support owe it as a duty 
to publish annually a clear, detailed and perfectly intel- 
ligible financial statement. Surely funds devoted to the 
giving of instruction or the prosecution of research can 
not be too carefully accounted for or too wisely expended. 

It is unfortunate that throughout the length of our 
great Atlantic seaboard there is no situation well suited 
to the establishment of a marine laboratory which may 
remain active throughout the year. In winter the frozen 
harbors of the north, the relative inaccessibility and deso- 
lation of the Carolina shores, the hurricane season of 
Florida interpose practical barriers to the plan of main- 
taining any one of our stations constantly open. We 
have no Naples with its brilliant bay, its genial climate, 
and over it as a veil the association of history deepening 
every charmed impression of its beauty. 


BIOMETRY AS A METHOD IN TAXONOMY! 


PROFESSOR CHARLES LINCOLN EDWARDS — 
TRINITY COLLEGE 


We take it for granted that the systematic description 
of plants, and animals, is not the province of the amateur, 
however interested he may be in a special group of living 
things. To the contrary this work should be done by 
the professional botanist, or zoologist, and demands a 
high grade of trained skill and judgment. More intel- 
ligence is needed than suffices to carefully fill out a card- 
for a catalog, and yet how often do we find descriptions 
of species that would be discreditable to even a librarian’s 
assistant! 

The characters of one species are sometimes described 
as ‘‘smaller,’”’ ‘‘longer,’’ ‘‘darker’’ or ‘‘lighter’’ than 
those of another, but upon reading the description of the 
other species referred to, the characters are again equally 
lacking in exactness. It is useless to enlarge upon this 
item, for every naturalist is sadly familiar with such 
imperfect and inadequate descriptions. 

Biometry offers a method of great value for the study 
of specific characters, and the consequent clear and 
definite statement of the results of such study. There 
are workers either frightened at the mathematics of the 
method, or scornful of the whole thing on the general 
principles of conservatism, or prejudice. The mathe- 
matics of biometry, considered merely as a biological 
working method, is that of simple arithmetic, with no 
operation more complicated than the extraction of the 
square root. 

It is certainly of great advantage to record in the 
standard deviation an exact mathematical statement of the 
variability of a character in place of the sometimes ut- 

‘Read at the Seventh International Zoological Congress, Boston, August, 
1907. 

537 


538 THE AMERICAN NATURALIST [VoL XOT 


terly meaningless, or again only partly useful, qualitative- 
phrases which may be given. The correlated variability 
of some of the characters is important. Descriptions 
based on the mean and range of variation of each char- 
acter and so expressed are better than those based on 
values taken here and there at random and then, when 
once published, petrified into a specific type ideal. A 
naturalist later tries to identify a specimen with this very 
limited description, but the characters of the specimen are 
too divergent and so a new species is created. Still later- 
another naturalist works with a hundred specimens, in- 
cluding the characters given for the two preceding 
species, and then synonymy is born and with it trouble- 
forevermore. 

As an illustration of the usefulness of biometry for the 
solution of taxonomic problems I may take the case of 
the common Florida-Caribbean holothurian described in 
1851 by Pourtalés as Holothuria floridana. In 1868,. 
Semper considered this species identical with H. atra 
Jäger, 1833, from the Celebes. All authors have fol- 
lowed Semper to the date of my publication (1905). In 
the meantime Ludwig, in 1883, recognized a species in. 
the West Indies different from the Indo-Pacific form and 
failing to identify it with H. floridana Pourtalés, created’ 
a new species, H. mexicana. The same error was re- 
peated by Theél, in 1886, in making his H. africana. 

With a feeling that things were not as currently ac- 
cepted, I concluded to apply the method of biometry to- 
this problem. From the United States National Museum, 
Harvard University, and my own collections, 138 speci- 
mens, covering nearly the whole geographical distribu- 
tion of the two species were available for the work. In 
the solution of the general problem before me no attempt 
was made to determine place modes of which, in minor. 
details, there were sometimes indications. Every im- 
portant character was submitted to statistical study and 
the result is that H. floridana Pourtalès is reestablished 
as a valid species, with H. mexicana Ludwig and H.. 


No. 500] BIOMETRY AS A METHOD IN TAXONOMY 539 


africana Theél as synonyms. The old characters have 
been redefined, new ones added, and those differentiating 
H. atra and H. floridana clearly stated. The young and 
old have been segregated and differentiated and the re- 
sults of growth determined. The nature and extent of 
the variation of each character has been recorded. An 
entirely new character for holothurians has been dis- 
covered in what I have called ‘‘pits,’’? in the body-wall 
of H. atra. 

It is not possible in taxonomic work to give several 
years to the study of each species and it often happens 
that the material is not sufficient. If an author will make 
a thorough biometric analysis of the characters of at least 
one- species in his group, he will gain a rare insight into 
the relative values of the characters. The method is 
searching and leads to especial carefulness in investiga- 
tion and statement. Even if one has not an ideal number 
of specimens his determinations are checked by their 
probable errors. In the case of some characters, as for 
instance, the spicules of holothurians, an abundance of 
material is present in each specimen. More and more 
of the anatomy becomes involved as the work progresses. 
Now that the individuality and continuity of the chromo- 
somes has been demonstrated, McClung has suggested 
that their number and grouping constitute family, gen- 
eric, and specific characters of just as definite worth as 
those that heretofore have been employed. The more 
characters studied the better, and the ideal taxonomy will 
be based upon the whole life-history. Then the error 
of describing the young and old of a species as inde- 
pendent species will not be repeated. 

It naturally follows from biometric analysis that a 
group of individuals, giving as much as possible of the 
range in variation, should be established and deposited, 
preferably in a national museum, as the specific type 
group rather than some arbitrarily selected type speci- 
men. We have instances of specifie descriptions based 
upon one individual, with an apology by the author for 


540 THE AMERICAN NATURALIST [Von XLII 


the lack of anatomical details because he could not dissect 
the one precious specimen! 

The best way to avoid trouble in taxonomy is to begin 
with making the original description as complete as pos- 
sible. It is then a simple matter to condense for practical 
diagnostic purposes. The biometric determination of 
the variability of the different characters allows of their 
arrangement in the order of increasing variability and 
will perhaps demonstrate which are the ‘‘best’’ char- 
acters. It is too soon to state exactly what percentage of 
divergence justifies the creation of a variety, or of a 
species, and it is not probable that any universally ap- 
plicable measure will be established. 

Biometry gives us data of value bearing upon one or 
more of the factors of evolution and records them in the 
best form for use. We know that under varying en- 
vironmental conditions different varietal, or specific 
forms respond. The new forms may be only temporary 
and followed by still other new forms, under other 
changed conditions, or with reversion, when the old condi- 
tions are restored. Characters, whether expressed in 
the terms of biometry, or not, are not permanently fixed 
by the publication of a specific description. It is to be 
hoped that the spirit of Darwin is with us yet and that 
we realize that species are in a state of evolution, either 
continuously or discontinuously, slowly or rapidly. If 
we are to follow species in their evolution we must have 
exact and comprehensive statements of their characters 
from time to time as it is possible, and, if in the terms of 
biometry, these statements are always in harmony and 
comparable. 

If then, while performing the necessary work of tax- 
_ onomy, we can make our descriptions more complete and 
nearer the truth; if occasionally we may be relieved of 
the necessity of creating a new species; if our work may 
contribute to the advancement of the philosophy of biol- 
ogy, should we not welcome biometry as a method which 
can well serve in one and all of these things? 


SHORTER ARTICLES AND CORRESPONDENCE 


THE GENUS PTILOCRINUS! 


Mr. F. A. Bather has just made known a second species of 
the interesting genus which I described a year ago? under the 
name of Ptilocrinus; his material was obtained in 70° 23’ S. lat., 
82° 47’ W. long., at a depth y about 480 meters ; the color of the 
animal in life is recorded as ‘‘flavus brilliant.” 

The type species of Ptilocrinus, P. pinnatus, came from the 
Queen Charlotte Islands, off British Columbia, and was dredged 
at a depth of 1,588 fathoms, about six times the depth at which 
P. antarcticus was found. 

Although at first sight, perhaps, it is somewhat surprising that 
the two known species should be found so far apart geograph- 
ically and bathymetrically, if we look closely into the matter 
we find that it is quite what we should expect. Geographically 
and bathymetrically the recent crinoids are divisible into three 
well-marked faunæ: (1) the Indo-Pacific-Japanese, characterized 
by the families Zygometride and Himerometride, the genera 
Comatula, Phanogenia, and most of the species of Comaster in 
the Comasteride, the genera Ptilometra, Asterometra, Calo- 
metra and one of the two species of Tropiometra of the Tropio- 
metridex,*® and the genera Perometra, Nanometra, Compsometra, 
Thysanometra and Iridometra of the Antedonide; among the 
stalked crinoids Metacrinus, Carpenterocrinus, Hrpalocrna. and 
Phrynocrinus are only known from this region; (2) the Polar- 
Pacific, including the Arctic and Antarctic circumpolar areas, 
and the entire American coast of the Pacific from Bering Straits 
to the Straits of Magellan, the coasts of eastern Asia to southern 
Japan (where it meets the preceding at Tokyo Bay), including 
the Sea of Okhotsk and the Sea of Japan, and the Atlantic coasts 
south to near the Hebrides and the Faroé channel, and to the 

1 Ptilocrinus antarcticus n. sp., a crinoid dredged by the Belgian Ant- 
arctic Expedition. Bull. de l’Acad. roy. de Belgique (classe des sciences), 
No. 3, mars, 1908, pp. 296-299, fig. p. 299 

2 Proc. U. S. Nat. Mus., XXXII, p. 551, fig. 1, p. 552. 

3 The second species, T. carinata, appears to have recently extended its 
range into the Atlantic. 

541 


542 THE AMERICAN NATURALIST [Vou. XLII 


Gulf of Maine, characterized by various genera belonging exclu- 
sively to the Antedonide, Heliometra occurring everywhere, 
Hathrometra confined to the north, and Isometra to the south, 
while Thaumatometra occurs in the south, but extends north- 
ward in the Pacifie to the Aleutian Islands; among the stalked 
crinoids the Bathycrinus carpenterii type (B. carpenteri, B. 
complanatus and B. australis) appear possibly to be peculiar 
to the region; bathymetrically, the characteristic forms (except 
Bathycrinus) are inhabitants of comparatively shallow water in 
both polar areas, but dip downward to a considerable depth 
when passing under the tropies; and (3) the Oceanic, which 
occurs everywhere in moderate to very deep water with the 
Indo-Pacific-Japanese, and extends thence over the entire ocean 
area, except that it does not intrude into the area occupied by 
the Polar-Pacific; the characteristic forms are the species of 
Thalassometra having rounded and spiny rays and arm-bases 
(such as T. bispinosa, T. villosa, T. gigantea, T. pubescens, T. 
multispina and T. aster) and certain other species, such as T. 
flava, T. porrecta and T, magnicirra, Stylometra, Bathymetra 


may be true of Calamocrinus. Although Heliometra occurs 

throughout this area, the two arctic species, glacialis (= esch- 

richtii) and quadrata (with their representatives in the Sea of 

Okhotsk, mazima and brachymera) differ from the Antarctic 

and east Pacifice species in the smoothness of their arms, and in 
* The subgenus Cenocrinus of Wyville Thomson. 


‘No. 500] SHORTER ARTICLES 543 


‘a different distribution of the brachial syzygia; we find, there- 
fore, that the entire Pacific portion of the Polar-Pacifie area, 
from Bering Straits to the Antarctic Ocean, is really an exten- 
sion of the latter division of the Polar-Pacific area northward; 
‘so that, had we reasoned backwards from the facts at hand 
before the appearance of Mr. Bather’s paper, we might very well 
have prophesied the discovery of a Ptilocrinus in the Antarctic 
regions. 

Mr. Bather remarks that I did not publish a generic diagnosis 
when I established Ptilocrinus; I did not, for the reason that 
in a monotypic genus, we are quite unable to say which are 
generic and which specific characters, and to tell in what way 
a new species will differ from the type; it is all right to indicate 
the differences provisionally between a new monotypic genus 
and older genera, but drawing up a diagnosis of a new mono- 
typie genus implies rather more of a tered over the 
animal kingdom than I am willing to assum 

Aat HOBART CLARE. 

UNITED STATES BUREAU OF FISHERIES. 


A NEW RHINOCEROS FROM THE LOWER MIOCENE 
OF NEBRASKA! 


Among several animals found by the writer at Agate, Sioux 
Co., Nebraska, in the spring of 1905, was a new form of hornless 
. rhinoceros. 

The type (No. HC105, collection of the writer) consists of a 
complete skull, the posterior portion of the left jaw, the atlas 
and the axis. This description has been delayed, hoping ad- 
ditional material might be secured. 

The specimen was found in an exposure of the P EOE 
Beds, about four miles west of the well-known Agate Spring 
Fossil Quarry, on the ranch of James H. Cook. The bone hiriión 
in this quarry is practically, if not identically, the same as that 
in the Agate Spring Quarry. Strictly speaking, the Dæmonelix 
Beds are an integral part of the Lower Harrison Beds, forming 
the upper portion of them. 

Associated with this specimen were the remains of Syndyo- 

1 Extract from a paper read before the American Society of Vertebrate 
Paleontologists, December 29, 1907, at New Haven, Conn. 


544 THE AMERICAN NATURALIST  [Vow. XLII 


ceras, Miolabis, Merychyus, Thinohyus, Parahippus, Moropus, 
Brachypsalis and other animals. 

The specimen is referred to the genus Aceratherium, and the 
specific name of egregius is proposed. It is separated from its 
contemporary Diceratherium, by the absence of horn cores, or 


Aceratherium egregius Cook. 14 natural size. 


any trace thereof on the nasals; by a relatively longer and pro- 
portionately narrower skull; by a larger first upper premolar, 
and by many minor features. 

The nasals are broad and flattened posteriorly, narrowing 
rapidly anteriorly, and extending about one half inch in front 


Molar-premolar Series. Right side. 1% natural size. 


of the premaxillaries. The temporal ridges unite in forming a 
sagittal crest, which rises quite abruptly, adding oey to 
the general saddle-shaped appearance of the skull. 

A more complete report will appear in volume three of the 
Nebraska State Geological Survey. 


No. 500] SHORTER ARTICLES 545 


MEASUREMENTS 
Mm. 
Grontest longth ach ch eek oie ie wera es 473 
xtreme width across zygomatic arches ............... 245 
. between orbits across frontals ............... 140 
OF: pidin CANG anea a eee Ob ea a eee 90 
yan of upper molar—premolar series—left side ..... 202 
Length of upper molars, left side -osio enrio 95 
Length of lower molars, left side «....... 0.66.0. .006 100 
Longth of dastana e T tO MOMOE ae orua ant ce ows 61 


HAROLD JAMES COOK. 
THE UNIVERSITY OF NEBRASKA, 
March 1, 1908 


NOTES AND LITERATURE 


_, PLANT CYTOLOGY 

Some Recent Research on the Cilia-forming Organ of Plant Cells. 
—The blepharoplast, or cilia-forming organ of plants, is present 
in the sperms and other motile gametes and in the zoospores. 
When fully developed it lies close against the plasma membrane 
of the cell in the form of a granule or band of various shapes 
to which the cilia are attached. The origin of the blepharoplast 
has been the subject of considerable research with conflicting 
conclusions. 

Strasburger in 1900 from studies on the zoospores of @Œdo- 
gonium, Cladophora and Vaucheria decided that the blepharo- 
plast arose in the plasma membrane (Hautschicht), the nucleus 
lying in close proximity at the time of its formation; Mottier 
later described a similar origin for the blepharoplast of Chara. 
In sharp contrast to the above conclusions are those of Belajeff 
from studies on the sperms of certain pteridophytes, Ikeno for 
Cycas and Marchantia, and Hirasé for Ginkgo, who hold that 
the blepharoplast is an attractive sphere or centrosome. Bela- 
jeff in particular has consistently described the blepharoplast 
as occupying, as a centrosome, the poles of the spindle in the 
mitosis previous to the formation of the sperm mother cells, and 
has held that the blepharoplasts of Marsilia came from cen- 
trosomes passed on from the previous mitoses ; each sperm mother 
cell being thus supplied with a blepharoplast. Ikeno, especially 
from studies on Marchantia, also holds to the centrosome nature 
of the blepharoplast, but his conclusions are disputed by Miyake. 
A third group of investigators to which Davis and Yamanouchi 
also belong (as will be noted from the reviews which follow) 
have deseribed the blepharoplast as arising in the cytoplasm 
while the nucleus is in a resting condition, and as holding no 
genetic relation to any preceding mitoses. Thus Webber from 
very thorough studies on the cycad Zamia described the blephar- 
oplasts as developing de novo on opposite sides of the nucleus 
and at some distance from it before the mitosis that precedes 
| the differentiation of the sperm nuclei; Shaw for Marsilia also 


No. 500] NOTES AND LITERATURE 547 


claimed that the blepharoplasts did not occupy the poles of the 
spindle in the final mitosis, as would be expected of a centrosome- 
like body. 

These divergent views have great theoretical interest in rela- 
tion to the subject of the polar organization of cells reviewed in 
the July number of the NATURALIST. Zoospores invariably 
present a conspicuous polarity since their cilia are situated at 
one end or at a definite point on the side, and while the complex 
coiled structure of many sperms obscures this polar organiza- 
tion the process of blepharoplast development is always from a 
region which is clearly a pole of the cell. Indeed, these types 
of cells present some of the best illustrations of complex polar 
organization. Perhaps the most vital problem of zoospore 
formation and spermatogenesis is then the question whether or 
not the polar organization of these cells arises de novo at the 
time of their development or is handed on from the succession 
of cells which are their progenitors. 

Davis! found in the zoospores of Derbesia a very interesting 
subject for the.study of a remarkable blepharoplast. Derbesia 
is a marine green alga in the group of the Siphonales, distin- 
guished from other forms in the same group by having very 
large zoospores, each of which is provided with a circle of 
numerous cilia. These zoospores are developed in a large spo- 
rangium which contains at first several thousand nuclei, but a 
process of nuclear differentiation begins very shortly in the 
young sporangium; certain of the nuclei increase in size while 
the great majority begin to degenerate and finally break down. 
The large surviving nuclei become distributed rather uniformly 
throughout the protoplasm of the sporangium, and each is evi- 
dently the center of dynamic activity for the cytoplasm in its 
vicinity. This is indicated by the arrangement of numerous 
conspicuous protoplasmic strands which radiate from the nucleus 
between the surrounding plastids. 

The segmentation of the protoplasm does not begin until the 
process of nuclear degeneration is practically ended, and the 
sporangium contains only the larger nuclei (from 30-300), 
which are to take part in spore formation. Cleavage furrows 
start from the periphery of the sporangium and eut into the 
protoplasm in the form of curved and branching furrows, 

1 Davis, B. M. Spore Formation in Derbesia. Ann. of Bot., XXII, p. 
i, 1905. 


548 THE AMERICAN NATURALIST (Vòt XLII 


These at first mark out large areas, which, however, become suc- 
cessively smaller as new furrows are formed at the periphery or 
strike off from the sides of the older ones. Finally the proto- 
plasm of the sporangium becomes divided into approximately 
equal masses around the large surviving nuclei., These masses 
are the zoospore origins and each develops into a uninucleate 
zoospore. 

The nucleus first lies at the center of the zoospore origin, with 
protoplasmic strands radiating out in all directions among the 
plastids. Granules are present at the bases of the protoplasmic 
strands close to the nuclear membrane. The nucleus then moves 
somewhat towards the periphery of the cell and it becomes clear 
that the protoplasmic strands on that side at least actually 
extend to the plasma membrane; these strands become arranged 
in the form of a funnel with the broader end against the plasma 
membrane. With this stage the zoospore origins clearly exhibit 
a polar organization. 


divisions in the sporangium. Third, the polar organization of 
the maturing zoospores does not appear to be present in the 


No. 500] NOTES AND LITERATURE 549 


younger stages when the nucleus occupies a central position in 
the zoospore origin. 

Yamanouchi? has given an account of spermatogenesis for 
Nephrodium in one of a series of papers dealing with the life 
history and apogamy of this fern. The blepharoplasts arise 
de novo just before the last mitosis in the antheridium, that 
mitosis which differentiates the sperm mother cells. They are 
first seen as small bodies lying within the cytoplasm on opposite 
sides of the nucleus and at a considerable distance from it; they 
appear suddenly, as differentiated by staining, and are unex- 
pectedly large. The blepharoplasts move towards the nucleus 
and during the final mitosis take positions near the poles of the 
spindle. Sometimes the blepharoplasts may lie exactly at the 
poles of the spindle, and consequently suggest relationships to a 
centrosome, but this is not often, and there can be no such 
relationship 1 in Nephrodium because centrosomes are not present 
in the earlier mitoses of the antheridium or at any other period 
of the life history. 

As a result of the final mitosis in the antheridium each sperm 
mother cell receives one of the two blepharoplasts close by the 
side of the daughter nucleus. The nucleus in the sperm mother 
cell now increases in size and the blepharoplast, at first spherical, 
changes its form. It enlarges and is flattened somewhat against 
the side of the nucleus and begins to elongate. The outline be- 
comes at first rhomboidal and then band-shaped as the blepharo- 
plast gradually extends around the nucleus in the form of a 
semi-circular band. 

A complicated development follows for both the nucleus and 
the blepharoplast. One end of the blepharoplast grows wedge- 
shaped and is loosely applied to the nucleus while the other end 
remains pointed and extends around in very close contact with 
its surface. The nucleus meanwhile changes its form, becoming 
a coiled structure and the elongating blepharoplast follows the 
coils in the form of a narrow band, which reaches to the end of 
the nucleus, and finally by extensive lateral growth covers the 
coil. In this manner the coiled and spiral form of the sperm 
is developed, and by this time numerous cilia have grown from 
the surface of the blepharoplast. 

There is another structure in the sperm mother cell which 

2 Yamanouchi, Sh. Spermatogenesis, Oogenesis, and Fertilization in 
Nephrodium. Bot. Gaz., XLV, p. 145, 1908. 


550 THE AMERICAN NATURALIST [Vor XLII 


must be briefly described. It appears as a minute body in the 
situation previously occupied by the central spindle of the final 
mitosis, and consequently far removed from the blepharoplast, 
which lies near the polar region of the spindle, with the nucleus 
between them. This structure is the ‘‘Nebenkern’’ of other 
authors. The ‘‘Nebenkern’’ later occupies various situations in 
the cell, but always remains as a small structure and does not 
enter into the construction of the spiral body of the sperm; it 
finally comes to lie in the cytoplasm which becomes attached, as a 
vesicle, to the posterior coil of the mature sperm. 

Yamanouchi’s results on Nephrodium are opposed to those of 
Belajeff for Marsilia, who holds that the blepharoplasts like 
centrosomes occupy the poles of the spindle and are derived from 
centrosomes in a previous mitosis within the antheridium. The 
account agrees with Webber’s conclusions for Zamia that the 
blepharoplast arises de novo in the cytoplasm, and also with 
Shaw’s view for Marsilia that the blepharoplast has no genetic 
relation to the pole of the spindle in the final mitosis. 

It seems probable that the centrosome theory of the blephar- 
oplast, as held by Belajeff, Ikeno and others, has placed undue 
emphasis on the proximity of the blepharoplasts, in the types 
studied, to the poles of a closely associated mitosis. There are 
no mitoses present during the entire period of zoospore formation 
in Derbesia, which consequently offers important evidence 
against this view. Since similar conditions are also present 
during zoospore formation in Œdogonium and a number of other 
alge, the investigation of these types is likely to prove very 
interesting. The blepharoplast unquestionably gives a marked 
polarity to the cell, but it has not yet been established that this 
polar organization is derived, as such, from the immediate cell 
progenitors, however pleasing, for theoretical reasons, would be 
the establishment of such a history. 

: Braptey M. Davis. 


ORNITHOLOGY 


_ Riddle on the Genesis of Fault-bars and the Cause of Alternation 
of Light and Dark Bars in Feathers.’—_In a much shorter paper 

‘Riddle, Osear. „The Genesis éf Fault-bars in Feathers and the Cause 
of Alternation of Light and Dark Fundamental Bars. Biological Bulletin, 
Vol. XIV, No. 6, May, 1908, pp. 328-370, pls. xii-xv. - 


No. 500] NOTES AND LITERATURE 551 


published in February, 1907, under the title ‘‘A Study of Fun- 
damental Bars in Feathers” (Biol. Bull., XII, 1907, pp. 165- 
174) the author gave a résumé of the results of studies here 
extended and for the first time fully set forth. The existence 
of ‘‘fundamental bars’’ in feathers was discovered by Whitman 
in the summer of 1902 (not published till 1907), who found 
them ‘‘to be common to all species of pigeons and birds in gen- 
eral,’’ and that they ‘‘appear to mark all feathers of all species 
of birds.’’? The present research was undertaken at Professor 
Whitman’s suggestion, whose observations furnished the start- 
ing point for these studies.. These are: ‘‘First, there is in all 
feathers a ‘fundamental barring’ of the whole length of the 
feather; second, certain defects (fault-bars) occasionally sier 
in the plumages of birds reared under adverse conditions.’ 
The fault-bars are considered as regards (1) their morphology, 
(2) their extent and distribution, (3) their cause. Whitman’s 
suggestion that fault-bars are due to malnutrition has been 
abundantly proved by experimental research. While normally 
- due to lack of nutrition, they may be produced by feeding birds 
on Sudan III, by mechanical injury of the feather germs, by 
bad sanitation, parasites, ete., and by the use of amyl nitrite to 
reduce blood-pressure. From extended observation and experi- 
ment it has been determined that ‘‘fault-bars are normally laid 
down at night,’’ when the blood-pressure is normally low. The 
interrelated facts bearing upon this assumption are thus stated: 
**(1) Diminished feeding of birds produces emphasized fault- 
bars. (2) Artificially reduced (amyl nitrite) blood-pressures 
produce equivalent defects. (3) The fault-bars are produced 
at night. (5) The lowest daily temperature in birds occurs 
from 1:00 a.m. to 5:00 a.m. (6) Other physiological con- 
ditions of the bird seem to be favorable at night for the produc- 
tion of low blood-pressures. (7) A lowering of the pressure 
would reduce the PORPRA and have a tendency to produce 
defects. ”? 

Those parts of the feather which are grown under the poorest 
nutritive conditions are the so-called ‘‘fault-bars,’’ while the 
intervening parts—normally the larger—are the result of the 
highest nutritive conditions, and form the ‘‘fundamental bars.’’ 
The structurally weakened bars are also found to be less pig- 


2 Bull. Wisconsin Nat. Hist. Soc., V, January, 1907, p. 13. 


552 THE AMERICAN NATURALIST [Vow XLII 


mented, although the difference in this respect between ‘‘fault- 
bars” ‘‘fundamental bars’’ is not marked, but results in 
the melanin pigment being ‘‘laid down in alternating light and 
dark transverse bars.’’ 

Among the results summarized by the author as confirmed by 
or resting upon these investigations may be mentioned: The 
occurrence of fault-bars normally in all birds and in all feathers; 
they can also be produced experimentally. A daily blood-pres- 
sure rhythm with a minimum pressure between 1 and 5 A.M. 
‘The reduced nutrition brought about daily by this minimum 
blood-pressure; the disadvantageous position, in relation to the 
blood, of the pigment and barbule elements of the feather; to- 
gether with the very rapid rate at which feathers grow, furnish 
the complex of conditions which bring unfailingly into existence 
a fault-bar, and to a more or less appreciable extent a light 
fundamental bar, at perfectly regular intervals in the entire 
length of every feather formation.’’ ‘‘The melanin pigment of 
the feathers of birds shows, under favorable conditions, quanti- 
tative variations of the pigment produced in response to changes 
in the available food supply. This is an additional evidence 
that this pigment is not a derivative of hemoglobin, but of the 
serum or cell proteids.’’ ‘‘These results furnish a description 
in the terms of physiology, of the mechanism of the ‘inheritance’ 
of certain fundamental color-characters of all birds.’? ‘‘The 
fundamental bars furnish the starting point for all evolutionary 
studies on the color-characters of birds.’’ 

These investigations may well serve as the foundation for 
researches upon the color-characters of birds, but whether they 
are to throw much light upon the genesis of color patterns in 
plumage remains for the future to disclose. It may be noted 
that no reference is made in this connection to the cause of dif- 
ferentiation of feather structure, treated by the author in a 
former paper. 


HERPETOLOGY 
Ruthven’s Variations and Genetic Relationships of the Garter- 
‘snakes.'—This paper of over two hundred pages, devoted to a 
' Ruthven, Alexander G. Variations and Genetic Relationships of the 
Garter-snakes. U. S. National Museum Bulletin 61, 8vo, pp. xii + 301, with 


st text 5 Sigares and 1 half-tone plate. Wiskbiston, Government Printing 
ce, 


No. 500] NOTES AND LITERATURE 553 


single genus of snakes, marks a new departure in North Amer- 
ican herpetology in respect to methods of procedure. An at- 
tempt is made first to determine the value of the characters 
commonly employed in distinguishing the different forms of the 
group, as scutellation and color, through study of the normal 
range of variation in the number of dorsal rows of scales, num- 
ber and arrangement of the labial and preocular plates, the 
number of the ventral and subeaudal plates, and the position 
and color of the stripes. All this is worked out with great care 
and detail for each form, so far as material is available, which 
includes about 3,000 specimens, gathered from throughout the 
known range of the genus. Distinction is made between indi- 
vidual, sexual and geographic variation. 

The individual variation in the number of rows of dorsal 
scales, and the variation in the different forms of the group, is 
found to be due to the dropping out of certain rows. The law is 
thus stated: ‘‘The individual, geographic and racial variations 
in the number of dorsal scale rows in the garter-snakes is brought 
about by the shortening and loss of the same scale rows as are 
ordinarily dropped posteriorly in conformity with the taper of 
the body, and there is evidence that this decrease is due to a 
dwarfing of the body.”’ 

The cause of variation in the number of labial plates is not 
easily explained, but it is believed that there is good reason ‘‘for 
concluding that whatever the factors may be that influence the 
number of labial plates, the variations are geographic and have 
been the basis for the racial differences that now exist.’ 

The color pattern in Thamnophis consists of three light longi- 
tudinal stripes—a median, and a lateral stripe on each side of 
the body—on a dark ground. They vary in width in different 
individuals of the same form, and also more or less in color. The 
median stripe is the most variable, and in some of the forms 
it is more or less obsolete. The lateral stripes are constant in 
position (in reference to the rows of scales involved), and as the 
position varies in different groups of forms it is available in 
diagnosis. Simple variation in color, however, has little diag- 
nostic significance, owing to the wide range of individual varia- 
tion within each form; ‘‘and, even when there are well marked 
geographic differences among forms, those in the same region 
tend to be similarly colored, as Allen has pointed out a number 
of times in mammals and birds, so that it is impossible to dis- 


554. THE AMERICAN NATURALIST [Vou XLII 


tinguish them sharply on this basis.’’ Thus there is ‘‘a marked 
increase in bright colors in the Pacific coast region in Wash- 
ington, Oregon and British Columbia,’’ and an increase in this 
same region ‘‘in the amount of black pigment at the expense of 
the paler colors.’’ ‘‘A tendency toward a paler ground color 
and lighter stripes’’ is noted in western Texas, southern New 
Mexico, southern Arizona and northern Mexico, and ‘‘a tend- 
ency toward the production of red pigment on the Great Plains,’’ 
and ‘‘toward dark colors in the forest region of eastern United 
States. ’’ 

As a result of these detailed studies of variation and their 
probable causes and significance, the taxonomy of the group here 
presented is quite different from that of preceding authors. Only 
19 ‘‘forms’’ are here recognized, in place of the 30 currently 
admitted by herpetologists. The author says: 


“Tt may seem the extreme of ‘lumping,’ to assert that there are but 
four great groups or lines of descent in the garter-snakes, but I be- 
lieve the evidence is sufficient to warrant the assertion.” 


These four groups are the radix, sawritus, elegans and sirtalis 
groups. He explains in a footnote (p. 39): — 


“Tt is best at the outset to ignore all questions of species and sub- 
species until their status is established, and to speak of these as forms. 
Forms, therefore, in the sense employed in this paper, are actual 
combinations of traits, having geographic extent, irrespective of whether 
they are isolated (species) or intergrade with their neighbors (sub- 
species). Detailed discussions of questions of nomenclature are also 
mre although the names are in every case the ones that, in the 

these investigations, we judge to be the right ones, following 
the dieses a Code of Zoological Nomenclature. The proper name 
of each form will be found in the footnotes, together with the 
synonomy.” 


In the ‘‘Table to illustrate the combinations of traits into 
forms, groups and divisions in the garter-snakes’’ (pp. 40, 41), 
the ‘‘forms’’ and ‘‘groups,’’ and ‘‘primary divisions’’ (the 
latter simply numbered I and II) are listed, but it would have 
been a great convenience if he had given somewhere in his 
monograph a list of the ‘‘forms’’ with their full names as here 
employed. ‘The form of nomenclature given in footnotes im- 
plies the provisional recognition of 12 species (binomials) and 

seven sian Be subspecies (trinomials), as follows: 


No. 500] NOTES AND LITERATURE 555 


1. Thamnophis megalops (Kennicott). 
2. Thamnophis marcianus (Baird and Girard). 3 
3. Thamnophis radix (Baird and Girard). T ir ee 
4. Thamnophis butleri (Cope). 
5. Thamnophis sauritus (Linné). 
5a. Thamnophis sauritus proximus (Say). +Sauritus group. 
5b. Thamnophis sauritus sackeni (Kennicott). J 
6. Thamnophis angustirostris (Kennicott). 3 
6a. Thamnophis angustirostris melanogaster (Peters). 
7. Thamnophis scalaris (Cope 
8. Thamnophis phenax ( ae. 
9. Thamnophis hammondi (Kennicott). 
10. Thamnophis ordinoides (Baird and Girard). 
10a. Thamnophis ordinoides elegans (Baird and 
Girard). 


-Elegans group. 


11. Thamnophis eques (Reuss). 

lla. Thamnophis eques sumichrasti (Cope). 

12. Thamnophis sirtalis (Linné). Sirtalis group. 
12a. Thamnophis sirtalis parietalis (Say). 

12b. Thamnophis sirtalis concinnus (Hallowell). 


Of these groups he states (p. ae that the sirtalis group ‘‘is 
without doubt the least diversified,’ since its members are given 
by most herpetologists only subspecific rank, owing to their evi- 
dent intergrading. 

Later on in the paper, in his ‘‘Discussion of Origins,’’ he 
gives his reasons for believing that the genus Thamnophis had 
its origin in northern Mexico, and not in southeastern United 
States, as held by Cope and Brown. The four ‘‘groups’’ are 
each represented in northern Mexico and southwestern United 
States, and ‘‘each group is formed of a line of directly related 
forms, the extremes of which are very distinct,’’ and these lines 
converge toward northern Mexico. He further states, under 
‘‘ Method of Evolution of the Forms” (p. 192): ‘‘If the range 
of the forms in the different groups of garter-snakes be care- 
fully examined it will be found (1) that the different forms of 
the same group are found in different geographical’ regions, 
characterized by different environmental conditions; (2) that 
the area along the common boundary of two forms of the same 
group, where transition in characters takes place, is relatively 


. 


556 THE AMERICAN NATURALIST [Vou. XLII 


narrow’’; just as has long been known to be the case in mammals 
and birds, and as Ortmann has recently affirmed to be the rule 
in crawfishes. 

He considers that 


“ Experimental work alone can sufficiently reveal the influence of 
the environment upon the dwarfing and scutellation of these snakes. 
In the case of the garter-snakes, however, it should be noted: (1) That 
most of the forms are the result of dwarfing. (2) That the amount 
of dwarfing does not seem to be directly associated with the nature of 
the environment, for the form inhabiting a particular region is only 
slightly different from its nearest neighbor in the same group, while 
forms of widely different scutellation may inhabit the same region. 
Thus the conditions which apparently determine the scutellation of any 
form is the seutellation of its immediate progenitor, and the dwarfing 
it has itself undergone.” 


He believes that he is ‘‘justified in concluding that the dwarf- 
ing is associated in some way with the environment.’’ He then 
cites Allen’s law (1876)? that the environmental conditions at 
the center of origin are most favorable for the existence of any 
group, and says: 


“ However this may be, the following facts will stand: (1) That the 
maximum scutellation and size in the genus Thamnophis occurs at the 
center of dispersal, and the forms that have been produced in the 
history of its migration have been formed principally by dwarfing and 
reduction in seutellation; (2) that the variation in the number of scales 
in the different series is definite and not promiscuous, and is correlated 
in a remarkable degree with changes in the environment. The develop- 
ment of the different groups has thus been orthogenetic.” 

He continues: 


“From these facts it seems to me that the most tenable hypothesis 
of the evolution of the genus Thamnophis is that it originated and 
became differentiated into four main groups in northern Mexico. From 


***Tn a general way, the correlation of size sas E distribu- 
tion ny! be formulated i in the following proposit 

me um physical development of hs ‘tadivinodl is attained 

think the conditions of environment are most favorable to the life of the 


8. ee 

‘2. The largest species of a group (genus, subfamily, or family, as the 
case may be) are found where the group to which they severally belong 
reaches its highest “pit gem or where it has what may be termed its 
center of distribution. . . —Bull. Geol. and Geograph. Surv. Terr., Vol. 
II, No. 4, p. 310, July l; 1876. 


No. 500] NOTES AND LITERATURE 557 


this region the groups radiated in all directions, but principally to the 
northward, and wherever they entered dfferent regions the changed 
environmental conditions acted as an unfavorable stimulus, which re- 
tarded growth, and differentiated the groups into dwarfed forms.” 

The first forty pages of this notable monograph are devoted to 
the taxonomy, distinctive features, and ‘‘variations’’ of the 
garter-snakes; the next one hundred and forty to a detailed 
account of the various ‘‘forms,’’ including description, habits 
and habitat relations, range, variation and affinities ; then follow 
about twenty pages of conclusions and general discussion, a 
bibliography of about 85 titles, and the index. The eighty-two 
text illustrations consist of diagrams showing the arrangement 
of the dorsal scale rows, the head plates, and the arrangement 
and numerical variation in the labial plates; diagrams illustra- 
ting the scale formula and its variations in the different forms; 
distribution as indicated by locality records (plotted on maps) ; 
and habitat views (half tones). It is altogether an excellent 
piece of work, which we hope to see emulated in other fields of 
taxonomic research, for which there is ample opportunity in the 
higher classes of vertebrates. 

In his introduction Dr. Ruthven alludes to the ‘‘barrenness 
of general results” that has marked the systematic work in 
herpetology, due in part to the method employed, which has 
been ‘‘largely analytical in its nature, being for the most part 
descriptive of the existing diversities.’’ While such work is 
important, it only makes known present conditions; as the 
author forcibly says, a knowledge of the processes that have 
brought them about is of the greater interest, since ‘‘systematic 
work can only become a true science when it seeks to formulate 
the laws involved in the history of the present forms. After 
analysis, pine as has been said, comes the need of a larger 
synthesis. ’’ 

Dr. Ruthven’s monograph strongly appeals to the present re- 
viewer for two reasons: First, when curator of reptiles at the 
Museum of the Boston Society of Natural History some thirty 
years ago, he spent much time in trying to unravel the in- 
tricacies of variation in the garter-snakes, with a view to publi- 
cation of the results, but other and more pressing interests inter- 
cepted the work; secondly, he repeatedly in the early seventies 
made strong appeals for the synthetic method in systematic 
work, and has published a large amount of data on individual, 


558 THE AMERICAN NATURALIST [Vou. XLII 


sexual and geographic variation. Forty years ago systematic 
work was almost wholly analytic, and especially so in respect 
to the mammals, birds and reptiles of this continent. In my 
paper ‘‘On the Mammals and Winter Birds of East Florida, 
with an examination of certain assumed specific characters in 
Birds,’’ ete., published in April, 1871,° the conclusions arrived 
at respecting “‘species’’ and specific characters are thus sum- 
marized :* 

“ (1) That the majority of nominal species originate in two prin- 
cipal sources of error, namely, (a) an imperfect knowledge of the 
extent and character of individual variation, and (b) of geographical 
variation. (2) That this imperfect knowledge is mainly due to the 
neglect of zoologists to study with sufficient care the common species 
of their respective countries, whence has arisen a faulty method of 
investigation and erroneous ideas respecting species and specifie char- 
acters. (3) Instead of the method at present pursued by a large school 
of descriptive naturalists—the analytic, or the search for differences— 
being the proper one, that synthesis should be duly combined with 
analysis, and that general principles should be sought as well as new 
forms, or so-called ‘new species’ and ‘new genera’ (4) It is claimed 
that nothing is to be gained by giving binomial names to climatic or 
other forms, in cases where, however considerable the differences be- 
tween them may be, a complete transition from the one to the other can 
be traced in specimens from intermediate localities, notwithstanding the 
plea sometimes urged that their use affords ‘convenient handles to 
facts.’ ” 

No 3 of these conclusions,’ here italicised, denotes the class 
of research exemplified by Dr. Ruthven’s monograph. His 
method of approach to the problem before him is thus stated: 

“ Three steps are necessary to determine the genetic relationships and 
simplify Cope’s elaborate arrangement of the group: (1) The value of 

* Bull. Mus. Comp. Zool., Vol. II, No. 3, pp. 161-450. 

* L. ¢, p. 163. 

* No. 4 may be considered as an entering wedge which led up to the 
later adoption of trinomials. In 1872 (Bull. Mus. Comp. Zool., Vol. III, 
ce k cae rea seq., July, 1872) varietal names were advocated and sys- 

at pted for intergrading forms, which were referred to as sub- 
species or races, the same method of designation being almost simultaneously 


interpo ti reviation ‘‘var.,’’ or by a letter (Roman or Greek 
according to the preference of the author); in 1877 and 1878 Gisonials, 
pure and simple, eame generally into use in this country for birds and 
mammals, and soon after for reptiles. 


No. 500] NOTES AND LITERATURE 559 


the characters must be determined; (2) geographic probabilities must 
be utilized; (3) similarities and intergradations must be sought.” 

As a result the 43 forms (20 species and 23 subspecies) recog- 
nized by Cope in his posthumous work ‘‘The Crocodilians, 
Lizards, and Snakes of North America” (Rep. Smiths. Inst., 
1898), are reduced to nineteen; and of the twenty-two names 
given by Cope eighteen appear only as synonyms. Nearly 
‘seventy names have been conferred on these nineteen forms, or 
an average of three and a half for each. 

Dr. A. E. Brown, the last preceding reviser of the group, in 
his ‘‘Review of the Genera and Species of American Snakes, 
north of Mexico,’’ published in 1901,° reduced the number of 
forms to eighteen—ten species and eight subspecies; he pro- 
ceeding on somewhat the same lines as Ruthven, namely, ‘‘that 
a knowledge of the laws under which forms are developed is to 
be best gained by a study of variations.” While the number 
-f forms admitted by the two authors is practically the same, 
the taxonomic results are widely diverse. 

Dr. Ruthven believes that the garter-snakes will be found to 
furnish excellent material for experimental research, as they are 
hardly in captivity, and prolific; and that the first problems to 
be attacked are the inheritability of scale characters and the in- 
fluence of inbreeding and unfavorable conditions of food and 
temperature. But it is to be remembered that experimental re- 
search must necessarily be conducted under unnatural conditions, 
and that the results do not necessarily show what has taken place 
under natural environments. While the results thus obtained 
are always interesting and suggestive, they can not be looked 
‘upon as conclusive respecting what has actually occurred under 
natural conditions. 

J. A. A. 


LEPIDOPTERA 


Hybrid Lepidoptera.—Although published more than a year ago, 
Mr. J. W. Tutt’s account of hybridization and mongrelization in 
anh is probably scarcely known to evolutionists in this 

two chapters in which he sums up and discusses all 

exe is ath on these subjects are prefaced to a much larger 

-work, the first volume of the ‘‘Natural History of the British 
* Proc. Acad. Nat. Sci. Phila., 1901, pp. 10-110. 


560 THE AMERICAN NATURALIST [Vou. XLIL 


Alucitides.’’ The book, a large volume of 558 pages, is part of 
Mr. Tutt’s exhaustive ‘‘Natural History of the British Lepi- 
doptera,’’ this particular volume dealing with the plume moths. 
The treatment of the several species is even more exhaustive 
than that given by Mr. Scudder in his great work on the butter- 
flies of New England; and as in Seudder’s work, the purely tax- 
onomic details are relieved by chapters on general topics. 

In his two chapters, Mr. Tutt enumerates all the recorded 
crosses between different species (hybrids) and between different 
forms of the same species (mongrels), and gives numerous par- 
ticulars about them. At the end of the book is an appendix 
describing other cases made known while the volume was in press. 
It appears that about 90 hybrid Lepidoptera are known, these 
being especially numerous among the Attacides and Anthro- 
cerides. The well-established hybrids have been reared in cap- 
tivity, and it is justly argued that many alleged hybrids found 
at large must be regarded with extreme suspicion, as being quite 
probably merely variations of one of the supposed parents. The 
most distantly related species which have, when crossed, pro- 
duced fertile eggs and subsequent larvæ, are Saturnia pavonia X 
Graellsia isabellæ; but in this case the larve could not be raised. 
to imagines. There is a very interesting discussion of the ques- 
tion whether hybridization is. capable of giving rise to new 
species in a state of nature. This is considered extremely un- 
likely, for the following reasons: 

‘‘Even when hybridity is not difficult to procure between two- 
species, the progeny shows little fertility inter se, and, although 
the males are more frequently fertile with females of either of 
the parent species, the female hybrids are much more rarely 
fertile with the males of the parent species, and at present few 
hybrids show comparatively free fertility inter se. This appears. 
to be largely due to the anatomical and morphological upset in 
the sexual organs of the female hybrids, an upset that frequently 
finds its outward recognition in the development of gynandro- 
morphic forms, in which the primary sexual characters are 
often considerably modified, and correspondingly marked changes. 
take place in the secondary sexual characters. 

‘‘ Assuming, however, hybridity ever to take place in nature, 
the hybrids themselves will often, presumably, follow one or 
other of the parent forms so far as relates to its habits, time of 
appearance, etc., and the chance of a male and female hybrid, 


No. 500] - NOTES AND LITERATURE 561 


assuming that some of both sexes get through successfully, then 
meeting each other, as against the possibility of either meeting 
and pairing with or being paired with a male or female of the 
much more abundant parent form, is so remote that one puts 
aside the possibility.’’ 

The instances of mongrelization are classified under the fol- 
lowing headings 

1. Crossing of typical form and local race. 

2. Crossing of typical form and aberration; production of 
artificial races by inbreeding. 

3. Crossing of typical forms with aberrations tending to de- 
velop melanochroie races. 

4. Crossing of typical form with aberration trying to set up: 
local race. 

5. Crossing of dimorphic forms of a species which occur to- 
gether and rarely appear to attempt to supplant each other. 

' 6. Crossing of typical forms with possible constitutional aber- 
rations. 

7. Dimorphism in one sex. 

It is impossible to give any summary of the many cases de- 
scribed under these headings, but enough has been said to show 
how valuable the work is to students of evolution and variation. 

D. A. COCKERELL. 


PARASITOLOGY 


Parasitic Diseases in the Philippines The paramount impor- 
tance of zooparasitic diseases in the Philippines may be judged | 
from the recently published record of the bureau of health since 
the medical work at Bilibid Prison was placed under its charge 
in November, 1905. The prevailing diseases treated in Hospital 
A, Bilibid Prison, were hookworm, 1,537 cases; amebie dysen- 
tery, 551 cases; acute dysentery, 174 cases; cholera, 18 cases; 
pneumonia, 62 cases; beriberi, 60 cases; conjunctivitis, 221 cases, 
and malaria, 174 cases; 81 per cent. were thus due to animal 
parasites. The death rate decreased from 238 per thousand in 
1905 to 13.5 per thousand in June, 1907. General sanitary 
measures were responsible for the first reduction to about 75 per 
thousand; active measures against animal parasites led to the 
further reduction. 


562 THE AMERICAN NATURALIST [Vor. XLII 


The establishment of a separate department of medical zoology 
in the curriculum of the Philippine Islands Medical School is a 
natural result of the extreme prevalence of animal parasites, 
and of the diseases to which they give rise. About 80 per cent. 
of the entire population is infected, or counting different spe- 
cies separately, 200 infections occur to each 100 inhabitants. 
While the severe results of such infection noted in Porto Rico 
and elsewhere are not found, yet the population of the Philip- 
pines presents a higher percentage of infection with intestinal 
worms than has ever been definitely reported from any other 
people and the condition is essentially a chronic one, the results 
of which manifest themselves indirectly in the general physical 
impoverishment of the people and the high rate of morbidity 
and mortality aceredited to other diseases. 


THE PATAGONIAN FAUNA 

Results of the Hamburg Magellan Expedition..—The importance 
attaching to a knowledge of the fauna and flora of the southern 
extreme of South America—especially in connection with the 
so-called ‘‘bipolarity’’ theories, and with the newly explored 
Antarctic fauna—has been recently more fully recognized. For 
a long period this region was neglected. Its great distance from 
the centers of scientific activity, the inclement climatic condi- 
tions, the unfriendly native population, the difficulties of naviga- 
tion which led every navigator to breathe more freely when he 
had seen the Magellanic mountains sink below the horizon in his 
, wake—all these factors contributed to the difficulty and cost of 
scientific exploration, and tended to turn the scale unfavorably, 
when projects of collecting expeditions were discussed in Europe. 
Yet the little that was known hinted of great interest in what 
remained to be discovered. The surveying expeditions of Fitz- 
roy, King, Wilkes, of Nares and Coppinger, the cireumnaviga- 
tions of U. S. S. Hassler and Albatross, the work of the Chal- 
lenger and of the French Mission to Cape Horn, in connection . 
with the international polar meteorological stations—each in its 
turn added something to the sum total of information about these 
regions. The growth of commerce, with the gradual exploita- 


*Ergebnisse der Hamburger Magelhaensischen Sammelreise, 1892-93. 
ne vom Naturhistorischen Museum zu Hamburg. Bde. I-III, 


No. 500] NOTES AND LITERATURE 563 


tion of the gold-washing and sheep-raising industries of southern 
Patagonia, made the region more accessible; the increasing use of 
steam in navigation diminished the terrors of the straits for 
sailors, and the occasional visits of seal hunters offered opportuni- 
ties for collection of other than fur ‘animals. Really valuable 
material obtained for the Hamburg Museum by the merchant 
captains and officers Ringe, Kophamel and Paessler drew re- 
newed attention to the subject, and projects of systematic ex- 
ploration were discussed by Dr. von Neumayer and director of 
the museum Professor Dr. G. Pfeffer. 

Times were unfavorable at first, due to civil war and other 
disturbances in Chile, and it was only in 1892 that it seemed 
prudent to actually despatch a collector. 

The financial question was settled by the generosity of citizens 
of Hamburg and by grants from various scientific societies of 
the city, and plans were decided upon under the skillful direc- 
tion of Dr. Pfeffer. The choice of Dr. W. Michaelsen as explorer 
and collector proved well advised. He left Hamburg in July, 
1892, returning in September, 1893, with an extremely large, 
valuable and well-preserved collection in all branches; a collec- 
tion believed to be the largest and most important ever brought 
from those shores. 

Some papers on part of this collection, or partly based upon 
portions of it, have already appeared in various publications, 
notably Strebel’s work on the mollusea, Michaelsen on the holo- 
somate ascidians, Hartlaub on the hydroids, and Ohlin on the 
valviferous isopods. 

Nearly all the various Antarctic expeditions of the last few 
years have touched, coming or going, on the Magellanic shores, 
and much of the zoological material contained in their elaborate 
reports has been gathered there. 

Meanwhile a multitude of specialists have been busy with the 
Michaelsen material and many of the papers during the last 
ten years have been separately issued. At the present time these 
have been brought together, united with others not previously 
published, and, under the editorship of Dr. Pfeffer, issued by 
the Hamburg Museum in three portly, beautifully illustrated 
volumes. 

The first volume, which relates to generalities, chordata, 
echinoderms and ccelenterates, has an historical preface by 
Neumayer, a brief account of his voyage by Michaelsen, and a 


564 THE AMERICAN NATURALIST [Von XLII 


very condensed summary by the editor, in which he points out 
in what papers the problems of zoogeography are touched upon 
from the standpoint of the student of special groups, with an 
intimation of what will be a most welcome general discussion in 
the future, of those problems from a general and inclusive point 
of view. 

The first paper is by Kustos Paul Matschie, of the Berlin 
Museum, describes eight species of mammals, of which one, a 
Herperomys, is described as new, and adds a catalogue of mam- 
mals of southern South America, which will be found useful, 
as it is annotated with mention of localities and enumera- 
tion of synonyms. As it is obviously impracticable to give with- 
in the limits of this review a synopsis of each of the multitude of 
papers of which these volumes are made up, the reviewer will 
endeavor to tabulate their contents so that those interested may 
find an indication of what they contain on each topic. The data 
on which each paper was originally separately issued are en- 
closed in parentheses. Each paper is separately paginated, 
there being no general pagination or plate numeration for the 
volume as a whole. 


VOLUME I 

* ł Säugetiere. Paul Matschie (1898), pp. 30, pl. 1. 

t Vogel. G. H. Martens (1900), pp. 34. 

7 Reptilien und Batrachier. Franz ong ee pp. 21, pl. 1. 

Fische. Einar Lönnberg (1907), pp. 

* Tunicaten. W. Michaelsen (1907), pp. a ‘3. 
* ł Holothurien. H. Ludwig (1898), pp. 98, pl. 3. 

* + Echinoideen. Max. Meissner TnP pp. 18, fig. 1. 
* ł Crinoideen. H. ee (1899), pp. 

*  Ophiuroideen. H. Ludwig (1899), pp. "98. 

* ł Asteroideen. Max. Meissner (1904), pp. 28, pl. 1. 
f Aleyonarien. Walther May (1899), pp. 22, figs. 3. 
f Zoantharien. Oskar Carlgren (1898), pp. 48, pl. 1 


f Paper gives a list enumerating all the species of the region known 
to date. 


VotumME Il—Arthropods, 
*Hemipteren. G. Breddin (1897), pp. 38, pE 2 
* Aphiden. H. Schouteden (1904), p. 6. 
*Formiciden. A. Forel (1904), pp. 8. 
Pteromaliden. Ew. H. Riibsaamen (1902), mp. 8, pL L 
+ * Coleopteren. H. Kolbe (1907), pp. 125, 
*Lepidopteren. O. Staudinger (1899), pp. 118, pl i. 


No. 500] NOTES AND LITERATURE 565 


* Trichopteren. Georg Ulmer (1904), pp. 26, pl. 2. 
Plecopteren. Fr. Klapálek (1904), pp. 14, figs. 10. 
Ephemeriden. Georg Ulmer (1904), pp. 8, pl. 1. 

*Odonaten. F. Ris (1904), pp. 44, figs. 12. 

* ł Apterygoten. C. Schaffer (1897), pp. 48, pl. 3. 
A i 


onyleptiden. W. Sörensen (1902), pp. 36 
* Ac P. Kramer (1898), pp 
* Pyenogoniden. J son (1907), pp. 20, figs. 6 


W. 
* 7 Süsswasser Ostracoden. W. V ra (1898) , pp. 26, figs. 5. 
7 Süsswasser Cladoceren. W. ee ra (1900), pp. 26, figs. 7. 
* Siisswasser Copepoden. Al. Mrázek (1901), pp. 30, pl. 4. 


VotuME III—Bryozoen und Würmer. 
* Bryozoen. L. Calvet (1904), pp. 46, pl. 3. 
ise 


nchytra Š ok i 

t * Terricolen (Nachtrag). W. Michaelsen (1899), pp. 28. 
+ * Polychaeten. E. Ehlers (1897), pp. 148, pl. 9. 
+ * Nemathelminthen. v. Linstow (1896), pp. 22, pl. 1. 

* Chaethognathen. O. Steinhaus (1900), pp. 10. 

* Nemertinen. O. Bürger (1899), pp. 14. 

* Cestoden. Einar Lönnberg (1896), pp. 10, pl. 1. 

Trematoden. M. Braun (1896), pp. 8, pl. 1. 


* Polyeladiden. Ritter-Záhony (1907), pp. 20, ai 9, pl. 
Rhabdocoeliden und Tricladiden. L. Bohmig (1902), pp. ri pi 2. 


The above summary is sufficient to show that these volumes 
form a library on the Patagonian fauna which will be indis- 
pensable to the student of the zoology of the southern hemis- 
phere. Almost without exception the papers conclude with a 
full bibliography of the subject of which they treat. We hope 
that the concluding volume of the series which will contain the 
editor’s general discussion will be also provided with a chart, if 
possible also bearing the bathymetric lines which indicate in 
a general way the topography of the sea bottom. 

Wm. H., Dat. 


566 THE AMERICAN NATURALIST [ Vor XLII 


COLOR NOMENCLATURE FOR NATURALISTS 


A Code of Colors for Naturalists.: —In 1905 Dr. R. M. Strong 
called attention in Science (Vol. XXI, pp. 267-268) to the avail- 
ability for naturalists’? use of the Bradley Educational Colored 
Papers. Little books containing about 165 samples of these 
papers may be had for five cents from dealers in kindergarten 
supplies. Since Ridgway’s ‘‘A Nomenclature of Colors for 
Naturalists’? went out of print, there has been no convenient 
and rapid means of designating colors with precision other than 
by the use of the Bradley papers. 

The present work attempts to furnish to all who have to 
designate colors with precision a simple, practical and unmis- 
takable means of indicating them. This is accomplished by 
supplying, at a low price, a book of convenient size for the pocket 
in which are contained a sufficient number of samples of dif- 
ferent colors arranged in accordance with a recognized scientific 
plan and prepared with materials as durable as our knowledge 
of chemistry permits. All names of colors are rejected except 
those of the six spectral colors, red, orange, yellow, green, blue 
and violet. Thus is avoided the confusion inseparable from the 
use of names for colors. The scheme includes 24 **pure’’ colors, 
the six colors of the spectrum named above; six other colors 
obtained by combining the adjacent spectral colors to produce 
intermediate colors called red-orange, orange-yellow, yellow- 
green, green-blue, blue-violet and violet-red; and twelve other 
colors intermediate between the twelve above named. Thus 
between red and red-orange there intervenes a lighter red, 
between red-orange and orange a lighter red-orange, so that the 
order of the twenty-four colors is as follows: red, red, red- 
orange, red-orange, orange, orange, orange-yellow, orange-yellow, 
yellow, yellow, ete. Each color is intermediate between that 
which precedes and that which follows it. Each of the twenty- 


iy 
and broken colors, in which the white and black are 
* Klincksieck, Paul, et Valette, Th. Code des Couleurs à l’usage des. 
Naturalistes, Artistes, Commerçants et Industriels, 720 Eechantillons de 
Couleurs classés d’après la méthode Chevreul simplifiée. Paris, 1908; 1 vol., 
86 pp., 4%4 X7% in. 48 pages contain 720 samples of colors, 


No. 500] NOTES AND LITERATURE 567 


used in definite proportions, are numbered consecutively with 
the pure color from which they are derived, so that the first 
double page of samples contains reds numbered from 1 to 25, 
the second reds numbered from 26 to 50, the third red-oranges 
from 51 to 75, the fourth red-oranges from 76 to 100. Thus the 
first 100 numbers are given up to red (including red-orange), 
the numbers from 101 to 200 indicate oranges (including orange- 
yellow), and so on through the spectrum, until the numbers 501 
to 600 indicate violet (including violet-red). In addition to the 
six hundred colors thus numbered consecutively, there are 120 
others, five on each page, all made by adding white to the pure 
color or to one of the broken colors and all designated by pre- 
fixing letters to the numbers on the same page. Thus the num- 
ber of colors is brought up to 720. 

To designate a color it is only necessary to refer to it by its 
code number. Thus a naturalist may describe the color of a bird 
as C. C. 120 (C. C. as an abbreviation for Code des Couleurs), 
and one reading his description knows at once, since the number 
falls in the second hundred, that the color is a broken orange 
and by turning to his code has the color itself before him. The 
naturalist may carry the book into the field and on a pencil 
sketch may enter the numbers of the colors of natural objects, 
and from such notes may, at his leisure, prepare colored figures 
of such objects, long after the objects themselves have faded. 
Thus there is provided an international code of colors which 
may be used like a telegraphic code and by means of which men 
of different nations and professions may intereommunicate with- 
out risk of being misunderstood. 

The scheme adopted in the code is a simplification of that used 
in the dye works at Gobelin and elaborated by the chemist 
Chevréul formerly in charge of the dye works. The simplifica- 
tion consists in reducing the number of pure colors from 72 to 
24, in greatly reducing the number of tints and shades and 
broken colors, and in omitting the grays. The omission of the 
grays is justified on the ground that all grays are in nature 
impure, and are therefore represented in the ‘“‘ Code” by shades 
or broken colors. The Chevréul scheme contains 14,421 colors, 
including grays, while the ‘‘Code’’ contains but 720, exeluding 
grays. The colors given in the ‘‘Code’’ are, however, so close 
together that only the trained expert will be able to discriminate 
intermediate colors; they are probably sufficient for all practical 


568 THE AMERICAN NATURALIST [Vou. XLII 


purposes. They are between 4 and 5 times as many as in the 
Bradley papers, which have also been arranged in accordance 
with the scheme of Chevréul (Milton Bradley, Elementary 
Color). 

M. Th. Valette, chemist of the government tapestry works at 
Gobelin, has selected the pigments used with special reference to 
their durability. The pigments have been applied to paper 
without the use of oil as a vehicle, so that their durability is 
thereby increased. The colored paper has been coated with an 
insoluble gelatin to protect it from the action of water. The 
paper thus prepared has been cut into samples 20 by 25 mm., 
and these have been pasted to the pages of the ‘‘Code.’’ The 
book, thus prepared, seems to answer the needs of naturalists 
far better than any other practicable scheme, and its use should 
greatly lessen the growing confusion which has resulted from 
attempts to designate colors by names without any standard of 
reference. The writer has tested the book in the field with 
satisfactory results. While not all colors may be matched by it, 
the results are accurate enough for practical uses, and greater 
accuracy is at present to be had only by the use of the color 
wheel. 

JACOB REIGHARD. 


(No. 499 was issued on July 31.) 


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THE 


AMERICAN NATURALIST 


Voi. XLII September, 1908 No. 501 


SOME RESULTS OF THE FLORISSANT EXPEDI- 
TION OF 1908 


PROFESSOR T. D. A. COCKERELL 


UNIVERSITY OF COLORADO 


Tue fourth University of Colorado Expedition to 
Florissant, in the summer of 1908, was only about three 
weeks in the field. The earlier expeditions, in 1905, 1906 
and 1907, obtained a very large amount of material from 
the Miocene shales of this locality, and much of this still 
awaits study and description. A general account of 
Florissant appeared in the Popular Science Monthly for 
August, 1908, while briefer statements, more or less in- 
accurate, may be found in the current geological text- 
books ;1 so it will not be necessary at this time to give a 
description of the place or the fossil-beds. It is pro- 

*In Dr. W. B. Scott’s valuable ‘‘Introduction to Geology,’’ 2d en 
(1907), p. 756, it is stated that there were ‘‘very few palms.’’ 
matter of fact, there is no reason for believing that there were any. The 
Rhus sp. on p. 755 is Weinmannia phenacophylla Ckll. In Vol. III (1906) 
of ‘‘Geology,’’ by Professors Chamberlin and Salisbury, Florissant is re- 
ferred to the Oligocene, flowing Scudder and others. It is stated that 
‘í palms are barely represented,’’ and yews are said to occur. We do not 


lirsch’s admirable work ‘‘Die Fossilen Insekten,’’ which would naturally 
be regarded as representing the best modern knowledge, numerous identifica- 
tions of Tertiary insects are cited, which certainly have no value. Thus 
Seudder had a specimen for Florissant which looked like a Bombus: this 
appears in the list, without any query, as Bombus. I have seen the specim en, 
and it is not a bee. In Dr. Folsom’s ‘‘ Entomology ’’ (1906) masses of 
Sialid eggs are said to occur; the eggs in question were not from Florissant, 
but from the Laramie beds at Crow Creek. 


569 


570 THE AMERICAN NATURALIST (Von. XLII 


posed, instead, to call attention to a few of the most in- 
teresting finds of this year, especially those which can 
readily be illustrated by photographs. Most of the work 
this year was done at what we call Station 13 B, close to, 
and apparently of the same materials as, Station 14, from 
which the best things of former years have nearly all 
come. Superficially, 13 B seems to dip under 14, but this 
appears to be due to a fault; both beds belong to the 
older series of the locality, being covered by extensive 
deposits of rock and shale, the greater part of which, at 
13 B, has been removed by erosion. 

The shale at 13 B proved extremely uneven in quality. 
During the first week the results were perhaps better than 
in any week of former years; but the last two weeks were 
relatively barren, and, as we were getting a large propor- 
tion of duplicates, it was doubtful whether the work justi- 
fied the expenditure. It is highly important, of course, 
that the Florissant beds should be further explored, and 
no doubt the treasures yet to be uncovered there are in- 
numerable ; but with limited resources, and great accumu- 
lations of unworked materials on ‘hand, it has seemed 
better not to continue digging at the present time. 

At the University of Colorado an exhibit of the Floris- 
sant fossils has been arranged. It is probably the best 
in existence, although the insect specimens in the Scudder 
collection at the Museum of Comparative Zoology, none 
of which are on exhibition, far exceed ours in number 
and variety. .From the recently gathered materials, a 
series will be prepared for Colorado College, and also 
one to be sent to Dr. R. F. Scharff, for the Dublin 

Museum. 

_ The members of the 1903 expedition were the same as 
in 1907, with the addition of Mr. Melford Smith, and, 
for a shorter time, Miss Gertrude Darling. 


THE FISH-GENUS TRICHOPHANES 
In 1872 Cope published Trichophanes, a new genus of 
Perciform fishes, represented by a small specimen ob- 
tained in the coal shales north of Osino, Nevada. In 1879 


No.501] THE FLORISSANT EXPEDITION OF 1908 571 


two other species, T. foliarum Cope, and T. copei Osborn, 
Scott and Speir, were added from the Florissant shales. 
T. copei, which has not been figured, is stated to differ 
from T. foliarum by its smaller scales. The genus is one 
of quite unusual interest, because it appears to belong 
to the suborder Xenarchi, an old group with peculiar 
anatomical characters, represented to-day by a single 
species, Aphredoderus sayanus, confined to the eastern 
United States. According to Jordan and Evermann, the 
Xenarchi are related to the Percopside, of which two liv- 


Fie. 1. Trichophanes foliarum Cope. 


ing species are known—FPercopis guttatus Agassiz, from 
the Great Lakes and surrounding regions, and Columbia 
transmontana Eigenmann, from the Columbia River. 
These fishes are evidently remnants of an ancient fauna, 
which in Tertiary times included a variety of genera and 
species. Agassiz, when describing Percopsis, was much 
impressed by its generalized features, combining char- 
acters which commonly existed together in Cretaceous 
fishes, but are widely separated in modern forms. ‘‘Now 
my new genus Percopsis is just intermediate between the 
Ctenoids and Cycloids; it is what an ichthyologist at pres- 
ent would searcely think possible, a true intermediate 
type between Percoids and Salmonide’’ (Agassiz, 1850). 
Tt is remarkable that this relic of earlier days should now 


572 THE AMERICAN NATURALIST (Vou. XLII 


have its headquarters in the area which was covered by 
the glacial ice; it is possible, perhaps, that it lived 
through the glacial period in some northern locality which 
was unglaciated, but cut off from the southern fauna. In 
this way, it might have been protected from the stress of 
competition, and when the great lakes were opened up, 
it found in them a comparatively free field—a field ap- 
parently not yet populated with anything like the maxi- 
mum number of species. 


Fic. 2. Trichophanes foliarum Cope. 


Trichophanes is not precisely typical of Aphre- 
doderidæ; it certainly seems to have some characters 
resembling those of the Percopsidæ, no doubt indicative 
of real relationship. It is readily recognized by its 
peculiar scales, which are ultra-ctenoid, with the mar- 
ginal teeth produced into quite long bristle-like struc- 
tures. According to Cope, they are ‘‘without or with 
very minute sculpture,’’ but under the compound micro- 
scope they are seen to be covered with fine concentric 
strie. 

Cope’s type of Trichophanes foliarum was obtained by 
Dr. Seudder, and consists of the anterior half of the fish 
only. This year my wife found at Station 13 B two prac- 


No. 501] THE FLORISSANT EXPEDITION OF 1908 573 


tically complete specimens, herewith illustrated. These 
reveal many characters not visible in the type, and em- 
phasize the Percopsis-like tendencies. In Jordan and. 
Evermann’s ‘‘Fishes of North and Middle America,’’ 
plates CX XI and CXXII, are given excellent figures of 
Pereopsis, Columbia and Aphredoderus. Our Tricho- 
phanes agrees with Aphredoderus in the thick (deep) 
caudal peduncle, the projecting lower jaw, and the scaly 
sides of the head. The dorsal fin, as in Aphredoderus, 
has three spines, the first very short, the third long (about 
12.5 mm.), the second intermediate. The anal, as in 


Aphredoderus and Columbia, but not as in Percopsis, has 
two spines, one long, the other short; the longer spine is 
nearly straight, as in Aphredoderus. The shape of the 
dorsal is very much like that of Percopsis, not very like 
that of Aphredoderus; while the forked caudal is very 
unlike that of the latter genus, but rather closely resem- 
bles that of Columbia. There is no adipose fin (it is 
present in Percopside) ; the ventrals are inserted about 
5 mm. posterior to the bases of the pectorals, and the 
same distance anterior to the level of the beginning of 
the dorsal. In the last character the fish is nearly in- 
termediate between Aphredoderus and the Percopside. 
Trichophanes should apparently be taken as typical of 
a family Trichophanide, falling in the Xenarchi, and 


574 THE AMERICAN NATURALIST [Vou. XLII 


standing between Columbia and Aphredoderus in the 
serial arrangement. 

Another waning group of fishes (with a single living 
species) found at Florissant is Amia, the bowfins. The 
accompanying figure shows a tail of this genus we found; 
much hunting failed to discover the rest of the specimen. 


A Primitive DRAGONFLY 
The Zygopterous dragonflies are divided into families 
known as Calopterygide and Agrionide. The Calop- 
terygide are further divided into subfamilies, separable 


Fic. 4. Phenacolestes parallelus Ckll, 


by the character of the costal region toward the base of 
the wing. In the Calopterygine, this area, before the 
nodus, is crossed by four or more veins, called antenodals ; 
in the other subfamily, the Lestinæ, these have been re- 
duced to two. In the family Agrionide, which is very 
abundant in the modern fauna, the reduction to two 
antenodals is practically universal. There is, however, 
an extinct subfamily, which I have called Dysagrionine, 
in which this reduction has not gone so far, and four or 
more antenodals remain. Of this group we know two 
genera, Dysagrion Seudd, from the Green River beds, and 
Phenacolestes Ckll. from Florissant. The latter genus, 


No.501] THE FLORISSANT EXPEDITION OF 1908 575 


published early in 1908 (Bull. Amer. Mus. Nat. Hist.) 
was known only from the wings. A photograph of a 
wing was sent to Dr. Needham, who wrote: ‘‘ It is indeed 
a most interesting fossil, another synthetic type. 

De Selys’? Podagrion group of Agrionine includes tlie 
most primitive members of that subfamily, and this fossil 
is more primitive in several characters than any living 
forms.” Very fortunately, a splendid specimen of 
Phenacolestes parallelus was uncovered this year by Mr. 
Geo. N. Rohwer. As the illustration shows, it is nearly 
complete, lacking, however, the apex of the abdomen. 
The wings are not so heavily clouded as in P. mirandus, 
the type of the genus, and there are differences in the 
venation. P. parallelus was originally described from 
the apical half of a wing. 


Somr Fossil BEES 
In 1906 (Bull. Mus. Comp. Zool.) I described a bee’s 
wing found at Florissant by Scudder, regarding it as the 
type of a new Anthophorid genus, Calyptapis. A very 


Fic. 5. Fossil bee, Calyptapis Fic. 6. Fossil bee, Anthophora 
florissantensis Ckll. melfordi Ckll. 


fine example, showing the body, was found this year, and 
from a close examination I am able to ascertain its true 
position. It is not an Anthophorid at all, but is a genus 
of Bombide, in other words a bumble-bee. The genus is 
valid, and gives the first indication of the former history 


576 THE AMERICAN NATURALIST [Vou. XLII 


of this group in America. The insect was especially in- 
teresting to me, because I had just been studying the bees 
in Baltic Amber, which include various genera and 
species of still earlier bees related to Bombus. 

Another bee of great interest was a species of Antho- 
phora, with the mouth-parts exserted and plainly visible. 
Some of the amber bees show the mouth-parts very well, 
but it is extremely rare for those in shale to show any- 
thing of the kind. The genus Anthophora is common in 
Colorado to-day, but it was not previously known from 
the American Tertiaries. 


A PROBLEMATICAL FLOWER 
Last year we found, among other flowers, one which 
was so interesting, and so well preserved, that Dr. Arthur 
Hollick made it the subject of a special article in Torreya, . 
September, 1907. Dr. Hollick named it Phenanthera 
petalifera, new genus and species, but was unable to place 


a 


Fic. 7. Fossil flower, Phenanthera petalifera Hollick. 


it definitely in any known family. A new specimen, 
figured herewith, is clearly of the same species, and on 
the whole confirms Dr. Hollick’s description. The 
stamens, with long filaments and large anthers, are cer- 
tainly eight in number. The supposed appendages of 
the calyx seem to me to be emarginate, and to resemble 
rather closely the small petals of certain Ribes. Follow- 
ing this clue, the large, thin ‘‘petals’? may be interpreted 
as petaloid calyx-lobes, also as in Ribes. The short 
pedicels, about the length of the hypanthium, suggest that 


No.501] THE FLORISSANT EXPEDITION OF 1908 oti 


the flowers were borne in clusters, and so in all respects 
they seem to agree sufficiently with Ribes, except for the 
insuperable difficulty of the eight stamens. The eight 
stamens would agree with Weinmannia, but the flower 
otherwise seems discordant, judging from the descrip- 
tions—I have never seen a Weinmannia flower. Both 
Weinmannia and Ribes are represented by leaves in the 
shale. 
THE PROBLEM OF THE PROTEACER 

The Proteacex constitute a rather large and very char- 
acteristic family, with over 950 living species, almost 
confined to the Southern Hemisphere. Nearly 600 are 
Australian; New Caledonia has 27, New Zealand 2, Chile 
7, tropical South America 36, South Africa over 250, 
Madagascar 2, and the mountains of tropical Africa about 
5. These particulars are taken from Engler (1894), 
probably the numbers should now be somewhat increased. 
The genus Helicia, with some 25 species, is Indo- 
Malayan, and extends north of the equator as far as the 
Himalayas. 

One of the most remarkable discoveries—if such it be 
—of paleobotany is that of the occurrence of Proteaceæ 
in abundance in the Tertiaries of the Northern Hemis- 
phere. In Ettinghausen’s work on the fossil flora of, 
Haring (1853) numerous remains of leaves are figured, 
together with drawings of recent species of Proteacer. 
The resemblances are not merely close; it is not too much 
to say that the oligocene leaves look practically identical 
with their modern representatives. Furthermore the 
resemblances are not shown in one or two types only, but 
extend throughout a considerable series; nor are they 
confined to the leaves—the determinations in some in- 
stances are fortified by characteristic-looking seeds. 
Even the peculiar fruits of Persoonia are shown. Such 
evidence looked convincing enough to Ettinghausen, and 
a priori, there seemed to be no obstacle. The distribution 
of the Proteacex to-day seemed to be that of a group once 
world-wide, but now driven to the ends of the earth by 
the stress of competition. This would agree well with 


578 THE AMERICAN NATURALIST (Vou. XLII 


the case of the marsupial mammalia, and others such as 
the recently elucidated one of the Chrysochloride, or 
golden moles. 

On the other hand, it was pointed out that there were 
other leaves resembling those of the Proteacer. In 1870 
Bentham went so far as to say, in regard to detached 
leaves, ‘‘I do not know of a single one which, in outline 
or venation, is exclusively characteristic of the order, or 
of any one of the genera.’ Quite recently Dr. Schonland 
(Trans. X. African Phil. Soc., 1907, p. 821) has written: 
‘The supposed identifications of southern types of plants 
in the Tertiary deposits of the Northern Hemisphere are 
considered by most eminent botanists, such as Sir Jos. 
Hooker, the late Mr. G. Bentham, A. Schenk, etc., as 
worthless. Laurent has recently tried again to prove 
that the Proteacexw originated in the North, but the evi- 
dence on which he relies seems to be altogether untrust- 
worthy.’’ Without having seen the European fossils, 
it may be hazardous to attempt any contribution to this 
controversy; but it must be pointed out that those who 
regard the paleontological evidence with contempt seem 
to have forgotten one or two things. They have not 
sufficiently remembered the great antiquity of the genera 
of flowering plants, as shown by indisputable evidence; 
they have failed to consider the great lapse of time, which 
would permit migrations from one end of the world to the 
other (continuous land provided), even at the slowest 
rate; and more especially, they seem to have forgotten 
the unquestioned cases of Sequoia, Comptonia, Liquid- 
ambar, etec., in which wide-spread types have been reduced 
to comparatively small areas within quite recent geolog- 
ical times. It may also be added, that they have over- 
looked the analogous cases among animals, which can by 
no means be explained away. With all this, it must be 
confessed that the dicta of paleobotany are not so reli- 

able as we could wish, and that an attitude of scepticism 
is often more than justified. 

Lesquereux believed that he could recognize a consider- 
able series (8 species) of Proteacex: in the Florissant 


No. 501] THE FLORISSANT EXPEDITION OF 1908 579 


shales. They are by no means so convincing as the 
European fossils; but they appear to represent an ele- 
ment now wanting in the North American flora, and no 
one has been able to show that they are not Proteaceous. 
I give figures of two of the most characteristic—Lomatia 
acutiloba and Lomatia tripartita. Our new material of 
L. tripartita is especially interesting as showing—what 
Lesquereux did not know—that it has compound leaves. 


Fic. 8. Lomatia tripartita Lx. Fic. 9. Lomatia tripartita Lx. 


These leaves are exceedingly variable, and have very 
much the cut of certain species of Phacelia. 

This question of the Proteaceæ is one of wide impor- 
tance, for it is not only a test of the accuracy of paleo- 
botanical conclusions, but, according as it decided one 
way or the other, it provides or removes an argument for 
the former existence of great southern lands between the 
present continents. 


580 THE AMERICAN NATURALIST (Yon XLII 


A Fossi MILKWEED 


On the same piece of shale as the Lomatia acutiloba, 
found by Mr. S. A. Rohwer at Station 20, is the follicle 
of a species of milkweed. It is 54 mm. long, 14 wide in 
the middle, dark colored as preserved, with a longitudinal 
suture and without tubercles. It closely resembles the 
follicle of the modern Acerates auriculata, but is rather 
less tapering. It may be known as Acerates fructifer, 
n. sp. <A similar follicle was described by Heer as 
Acerates veterana, and was found at Giningen and other 
localities. 


OPREA VAA EEE A ERE E A AASE EE SEa od 


Fic. 10. Lomatia acutiloba Lx., and follicle of Acerates fructifer n. sp. 


A SERVICEBERRY 


I give a figure of large serviceberry leaf, Amelanchier 
typica of Lesquereux. It is like that of the modern 
American A. canadensis, but the more cuneate base re- 
sembles that of A. intermedia. Other species of 
Amelanchier have been found at Florissant, all having 
a completely modern appearance, and showing that the 
minor groups of the genus were separated in the miocene. 


A’ PRICKLY ÅRALIACEOUS PLANT 


At Station 13B Mr. S. A. Rohwer found a leaf with 
five oblong, long-stalked leaflets, as preserved light red- 


No. 501] THE FLORISSANT EXPEDITION OF 1908 581 


dish in color, with the petiolules provided with small but 
very distinct recurved prickles. The leaflets are about 
48 mm. long and 24 broad, with a cordate base, and the 
margin with broad rounded teeth or pronounced crena- 
tions, each about 2.25 mm. long. The principal lateral 
veins, leaving the midrib at an angle of perhaps 50°, are 
about seven in number on each side, and are only moder- 
ately curved. The petiolules differ greatly in length, 
from 26 to 5 mm., and bear a moderate number of irregu- 
larly-placed prickles, these being about 2 mm. long. 


Fig. 11. Serviceberry leaf, Fie. 12. Panar andrewsii n. sp. 
Amelanchier typica Lx. 


Mr. D. M. Andrews, of Boulder, suggested to me that 
this fossil was Araliaceous, and upon looking the matter 
up, I felt satisfied that this must be correct. I sent a 
photograph to Dr. N. L. Britton, who kindly replied: 
‘‘There is no doubt that the photograph that you send 
represents some species of Araliaceæ, but I am not per- 
sonally acquainted with anything quite like it. A good 
many of the woody Araliaceæ have prickles.’’ From the 
leaf alone, the restricted genus must remain somewhat 
doubtful, but it may be permissible to refer the plant to 
Panax, under the name Panax andrewsii n. sp. 


EMBRYOLOGY OF MYOSURUS MINIMUS 


LEROY D. SWINGLE, Px.D. 


UNIVERSITY OF NEBRASKA 


THERE is a close superficial resemblance existing be- 
tween Myosurus and some of the lower forms such as 
the pines and the Selaginellaceae. For this reason the 
development of Myosurus presented itself as an inviting 
field of research. To be sure Bessey (1898) has already 
given the stages in the development of the pistils. My 
work in so far as it repeats these early stages serves as a 
confirmation of his description. 

The developmental stages correspond very closely to 
those of Ranunculus, which has been investigated by 
Coulter (1898). The arrangement of the pistils, how- 
ever, differs from that of Ranunculus in the fact that in 
Myosurus the receptacle is drawn out into a long central 
axis around which the pistils are arranged in spiral rows. 
Acropetal development of the pistils is very marked, so 
that the axis may lengthen nearly two inches after the 
pistils at the base have reached maturity (PI. I, Fig. 8). 
The pistils formed late in the season around the apex 
of the axis are not pollinated. In respect to this conical 
arrangement of megasporophylls and the mode of de- 
velopment of the megasporangia there is at least a super- 
ficial resemblance to the pines and Selaginella. 

As in most microsporophylls, so here there are four 
sporangia. At first the stamen is a mass of undiffer- 
entiated meristem (Pl. I, Fig. 1), but soon the limits of 
the sporangia become visible. The meristem cells within 
the areas which are to become sporangia begin to de- 
generate, while the first hypodermal layer becomes active 
in division. The cells, archesporial in character, divide 
periclinally to produce an outer primary wall cell and an 
inner primary tapetal cell. The former cell divides once 

582 


No.501] EMBRYOLOGY OF MYOSURUS MINIMUS 583 


or twice, producing three or four layers in the wall. The 
latter cuts off spore mother cells which take the place of 
the degenerating meristem. The tapetal layer appears 
to be the outer layer of spore mother cells which have 
sacrificed their reproductive function for the nourishment 
of the other cells (Pl. I, Fig. 2). In this earliest stage 
of tapetal differentiation, some of the tapetal cells are 
binucleate. <A little later practically all of them become 
binucleate and remain so till degeneration is accomplished 
(Pl. I, Fig. 3). This fact, to my mind, supports the 
theory that tapetal cells are potentially spore mother 
cells. The hereditary stimulus toward further division 
to form microspores is strong enough in them to carry 
the nucleus through one division, at which point their 
new function usurps control and arrests further develop- 
ment. 

The mother spores are few in number and as the 
anther enlarges become rounded off. and separated from 
each other (Pl. I, Fig. 3). The usual course of develop- 
ment now follows. The mother cells divide simulta- 
neously in a given sporangium to form first two and then 
four cells arranged either tetrahedrally or in the same 
plane (Pl. I, Fig. 4). The last three stages in the 
maturity of the microspores are shown in Figs. 5, 6 and 7. 
There are developed on the wall three thin spots for the 
extrusion of the tube. The tube nucleus, the round one, 
and the generative nucleus, the oval one, are always 
present before the pollen leaves the anther. Upon germi- 
nation the generative nucleus evidently divides, for two 
male nuclei are found in the pollen tubes. Degeneration 
of the tapetum is not very marked till the pollen grains 
are completely formed. In the mature anther not only 
the tapetum but all the other cells of the wall except the 
epidermis and first hypodermal layer have disappeared. 
This hypodermal layer develops heavy bands in the cell 
walls for breaking the anther. 

The pistil appears in its earliest stage as a small 
swelling on the side of the receptacle (Pl. I, Figs. 8-9). 


584 THE AMERICAN NATURALIST [Vou. XLII 


Soon this mass of cells bends a trifle downwards, and the 
anlage of the sporangium appears as a swelling in the 
distal axil formed by the juncture of the sporophyll with 
the receptacle (Pl. I, Figs. 8 and 10). The end of the 
sporophyll now begins to bend upwards and the ovule 
downwards. About this time the archesporial cell ap- 
pears as a single large hypodermal cell (P1. I, Fig. 13). 
When the ovule has bent downwards about 90° and the 
seed coats have begun to appear at its sides as slight 
elevations, the archesporium divides rapidly to form four 
megaspores, arranged approximately in a longitudinal 
row. ‘The first two, however, often lie more or less side 
by side (Pl. I, Fig. 11). In a few cases I found only 
three megaspores. This may have been because of tardi- 
ness in the division of one of the cells. Meanwhile a 
groove has been forming in the upper surface of the 
carpel, and as the carpel continues to bend upwards the’ 
ovule is entirely enclosed by the sides and bottom of the 
groove. By the time the megaspores are formed, the 
upper convex surface of the ovule has fused with that 
portion of the pistil next to it. The ovule now hangs 
loosely downwards in the cavity thus formed. The 
nucellus continues its circular movement and by the time 
it has bent 180° the megaspore next to the chalaza, the 
functional one, has enlarged, while the others have begun 
to degenerate. When the ovule has described an are of 
225° the functional megaspore has made its first division. 
Between the two nuclei a large vacuole, which continues 
to enlarge with the growing sac, is formed (Pl. I, Fig. 12). 
The cells at the sides of the sac crowd in between the 
sac and the epidermis. At this stage the seed coats are 
prominent and have three or four layers of cells. In the 
next stage the nucellus has advanced about 90° farther in 
its cycle and each nucleus of the sac has divided. With 
the increase in size of the sac, the cells round about it 
begin to degenerate. The seed coats are now as long as 
the nucellus (Pl. II, Fig. 14). While the nucellus is 
passing through the next 45° of are all the nuclei of the 


No.501] EMBRYOLOGY OF MYOSURUS MINIMUS 585 


sae divide, forming eight nuclei, four at each end of the 
sac. The nucellus now lies parallel to the axis of the 
receptacle with the micropyle, which is now completely 
formed, directed upwards (P1. II, Fig. 15). One nucleus 
from each end of the sac moves toward the center where 
they fuse to form the definitive endosperm nucleus (Pl. 
II, Fig. 17). At first this nucleus is characterized by two 
nucleoli (Pl. II, Fig. 19), the others having only one. 
Maturation is now complete, and the cell which is to be- 
come the functional egg cell may lie between or at either 
side of the synergids. 

The pistil has now reached its final stage. It makes a 
slight angle with the receptacle (Pl. II, Fig. 15). The 
stigmatic surface is marked by long spreading cells (PI. 
II, Fig. 16). The presence of chloroplasts in the cells of 
the style and epidermis will be noted. The ovarian 
cavity is almost entirely filled with the ovule. It is lined 
with a layer of cells which represent the original epi- 
dermal layer before enclosure took place. In surface 
view they are seen to be irregular cells with wavy walls 
(Pl. II, Fig. 24). Immediately underneath this layer is 
one, or in some places two, layers of long interlacing cells 
formed from the fibro-vascular bundle. They form a firm 
basket-like structure. 

Already, even before the definitive endosperm nucleus 
is formed, the pollen tubes are found in the micropyle. 
About the time of the formation of the endosperm nucleus 
the pollen tube enters the sac (Pl. II, Figs. 18-19). The 
synergids at once begin to degenerate. As the tube 
passes into the sac the egg nucleus and the endosperm 
nucleus move towards each other (Pl. II, Fig. 19). The 
cytoplasm around the egg nucleus becomes denser and 
soon distinct from the other cytoplasm. It is not certain 
about the conduct of the generative nuclei, actual fusion 
stages not having been observed. Except for a few - 
isolated observations the evidence points to the fact that 
the endosperm nucleus is fertilized by one of the genera- 
tive nuclei and the egg nucleus by the other. The isolated 


586 THE AMERICAN NATURALIST [Vou. XLII 


observations just mentioned were to the effect that both 
male nuclei were present in the sac after the endosperm 
nucleus had proceeded to divide. At any rate, whether 
the endosperm nucleus requires fertilization or not, it 
precedes the egg nucleus in division. This fact supports 
the theory that the endosperm is a portion of the gameto- 
phyte. 

The first division of the egg cell is periclinal, forming 
two cells, the distal one of which is destined to give 
rise to the embryo and the other the suspensor. These 
two cells then divide almost simultaneously, the former 
transversely, lengthening the suspensor, the latter longi- 
tudinally. Either may, however, precede the other in 
dividing. The four-celled stage is formed by a division 
of the two cells in a longitudinal plane at right angles to 
the first plane. One or both, generally one, of the cells 
of the suspensor divides transversely, thus completing 
the suspensor which possesses three or four cells (PI. II, 
Fig. 20). The proximal cell often broadens at its base. 
The next division of the embryo cells is at right angles 
to the other two planes of division and results in an eight- 
celled stage (Fig. 20). About this time the distal cell of 
the suspensor makes two longitudinal divisions at right 
angles to each other (Pl. II, Figs. 21-22). Numerous 
divisions follow in the usual manner (Figs. 21-22). In 
the last stages the exact arrangement of cells was hard 
to determine on account of the difficulty in sectioning the 
hardened wall of the sac. But the shape of the mature 
embryo with its two cotyledons and the approximate 
arrangement of cells are shown in Fig. 23. The embryo 
lies in a cavity about twice its size and so does not come 
into contact with the endosperm except at the base of the 
suspensor. 

The development of the endosperm is essentially sim- 
ilar to that of Ranunculus. The endosperm nucleus, 
fertilized or not, divides successively to form several 
nuclei distributed throughout the cytoplasm which radi- 
ates from them as centers. The antipodal cells number- 


No.501] EMBRYOLOGY OF MYOSURUS MINIMUS 587 


ing three, except in one case where four were present, 
become distinctly separated from the rest of the cytoplasm 
of the sac. After the first division of the egg cell the 
endosperm nuclei with their cytoplasm move to the 
periphery of the sac, where they form a complete lining 
one cell in thickness. The central portion of the sac is 
filled with a large vacuole (PI. II, Fig. 20). The nuclei 
continue their divisions till the whole sac is filled with 
endosperm. ‘This occurs about the eight-celled stage of 
the embryo. 

There is considerable variability in the time when the | 
walls appear, but it can be safely stated that they gen- 
erally appear a little after the eight-celled stage of the 
embryo (Pl. II, Fig. 22). However, they may occur when 
the sac is lined with the single layer of nuclei. The 
antipodals can still be seen, but are on the road to degen- 
eration. In one case I found a peculiar condition of the 
endosperm. At one end of the sac were the antipodals 
and at the other the synergids and egg-cell. Scattered 
in the cytoplasm of the central portion were three large, 
oval, endosperm nuclei containing several large nucleoli. 
One of them was dividing amitotically. 

The endosperm nuclei, like the pollen mother cells, 
always divide simultaneously. There is a rhythmical 
succession of activities. This rhythm is so closely fol- 
lowed that every nucleus is found in the same phase of 
mitosis at the same time. This condition is localized in 
individual embryo sacs and there must be, therefore, a 
mutual reflex stimulus among the nuclei of a given sac. 

As the embryo sac proceeds in its development the 
cells of the nucellus degenerate (P1. II, Fig. 14). By the 
time fertilization takes place all have disappeared except 
the original epidermal covering of the nucellus (PI. II, 
Fig. 18). At this stage the seed coats which possess 
three or four layers of cells have grown considerably 
beyond the nucellus to form the micropyle. When the 
endosperm nuclei take a peripheral position, the original 
epidermal layer begins to degenerate, except a few cells 


588 THE AMERICAN NATURALIST [Vor XLII 


at the base of the suspensor (P1. II, Fig. 20). The walls 
of the cells composing the innermost layer of the seed 
coats become somewhat thickened and rounded. Later 
the cells increase greatly in size and become very stony 
in texture. All the other layers except the external one, 
which forms a delicate membrane, disappear. 

By some botanists Myosurus has been considered a 
low type from which the monocotyledons and dicotyle- 
dons took their origin. This view was based principally 
upon its external vegetative structure. If it stands on 
the border line between these two groups, one would 
expect to find in its embryology features common to both 
and perhaps one well-developed cotyledon and another 
rudimentary one. But this is not the case. The cotyle- 
dons from their first appearance clear through the period 
of germination are exactly equal. And, furthermore, the 
other features of development are typically dicotyle- 
donous, corresponding to those of the other Ranuncu- 
laceæ. It is, however, to be regarded from its embryo- 
logical and vegetative fatures as one of the lowest, if 
not the very lowest, of the dicotyledons. 

This work was carried on in the department of botany 
of the University of Nebraska, under the direction of 
Dr. Charles E. Bessey, to whom I am indebted for his 
interest and assistance. 


LITERATURE CITED. 
1898. Bessey, E. A. The Comparative Morphology of the Pistils of the 
Ranuneulacee, Alismacee and Rosacew. Bot. Gaz, XX 
297-313. 
1898. Coulter, J. M. Contribution to the Life History of Ranunculus. 
Bot. Gaz., XXV, 73-88. 


EXPLANATION OF PLATES 
Drawings were " maáe with camera lucida. For clearness, all figures of 
pistils or their paris are placed on the page in the same relation to the draw- 
ower (Fig. 8) as a ae in nature between the flower and the parts 
here represented. 
PLATE I 
Bie, L. — section of an anther showing the region in which two co the 
: porangia develop. The cells are now undifferentiated. 


No.501] EMBRYOLOGY OF MYOSURUS MINIMUS 589 


Fic. 


2. 


e $ 


py 


a 


go 


_ 
ad 


te 
= 


w 
a 


24, 


Cross section of anther showing a single microsporangium. 
mother cells surrounded by the tapetal layer. The cells i pei 
wall are arranged radially. x 590. 

eae pe of anther showing the epidermis, two hypodermal 

rs of all, the tapetum composed of binucleate cells, and 
ah mother gies x 590. 

Four tetrahedrally arranged microspores cing the wall of the spore 
mother cell, x 590. 

Three microspores just after the dissolution of the mother wall. x 590, 

Still later stage of microspore with a thick wall. The nucleus has not 
yet divided. x 590. 

Mature microspore showing the large round tube nucleus and a 
e e nucleus. The three thin spots in the wall are visible. 

590. 
AEREA section through a young flower. A, anther. B, petal. 
, receptacle. S, sepal. P, pistil. N, nucellus. x35. 


t. 
Two-celled Jage of the embryo sac. Seed a appeat at the sides. 


x 
soe _appeara nee of archesporium. The pistil has bent upwards to 
ose the nucellus. x 210. 


PLATE II 
Four-celled stage of the embryo s The seed coats have grown to 
the end of the nucellus. The ells about the sac are degenerating. 


OES. 

Mature pistil and embryo sac with its three antipodals, two syner- 
gids, egg nucleus and endosperm nucleus, The dotted lines show 
the nap of the ptenbbambe bundles. 

The stigma of Fig, 15 highly magnified. x 210. 

Tae sac Saas ie the three antipodals, the two synergids and egg 

ucle and 5 


5 
E 
co 
zg 
3 
° 
B 
= 
k 

5 

+ 
E 
© 

= 
[za 
© 

= 

+ 
4 

° 

5 

g 

£, 
ei 
=, 
i=] 


Pres aa within ER sac. ale peg containing tre winabitive 
and tube nucleus, is betw he large endosperm and the 
Sains ae egg nucleus. The Faa synergids are shown at the 
side. x 2 
Eight-celled stage of the embryo. Three cells present in the suspensor. 
The 


endospe ry of th ac. Thr 
ataia nuclei of the degenerated nucellus still apparent, only 
ate ce se of the epidermal covering being left as a support for the 


x 340. 
A ene later stage of the embryo. The distal cell of the suspensor 
mr vided to form four cells, only two of which could be shown. 


sti nee embryo, In this case there were four cells in the sus- 
r before the distal one divided to pea four. At the left the 
x 340. 


pensor. xX 365. 
Surface view of epidermal cells lining the loculus. x 365. 


ANOTHER ASPECT OF THE SPECIES QUESTION 


DR. J. A. ALLEN 


AMERICAN Museum or NATURAL History 


Tue American Narurauisr for April last (Vol. XLII, 
No. 496, pp. 217-281) contains a report of the symposium 
held by the Botanical Society of America at its recent 
Chicago meeting on ‘‘ Aspects of the Species Question.’’ 
This series of eight papers should be of great interest to 
zoologists as well as to botanists, since it brings so 
strongly into relief the differences in view-point held by 
leading taxonomers in two widely different fields of 
research. 

The wide divergence of views here shown in relation to 
the ‘‘species concept’’ is no less surprising than are the 
measures urged by some of the speakers for the reduction 
of ‘‘taxonomic anarchy’’ in botany to some degree of 
reasonableness. The ecologic botanist needs some 
method of designating the minor variations which are so 
important to him in his researches, but from his point of 
view the question ‘‘ What is a species?’’ can be decided 
only by experimental research. In the meantime we may 
go on naming forms without essential modification of 
present methods. From another point of view, the nam- 
ing of new forms is to be repressed with the utmost rigor, 
even to the establishment of a ‘‘taxonomic censorship”’ 
upon ‘‘species-making.’’ While most of the speakers ap- 
pear to agree that there are no species in the Linnean 
sense, and that species are merely mental concepts, like 
genera and the higher taxonomic groups, there is a 
tendency to hark back to the Linnean concept, and to 
accept the Linnean standard as far preferable to the 
minute discriminations of modern taxonomers. From 
other points of view there may be physiological species as 
well as morphological species; there may be species that 

592 


No. 501] | THE SPECIES QUESTION 593- 


are fixed and immutable, others that yield readily to the 
forces of environment. That so-called species originate 
by different methods is evident, thanks largely to modern 
botanical research. The whole outcome of this sym- 
' posiùm, as it affects nomenclature, is naturally indecisive, 
but contributes a few reasonable suggestions for its im- 
provement. It is, however, a brilliant exposé of conflict- 
ing interests and conceptions. 

The state of unrest, and the dissatisfaction with the 
status quo here disclosed, are not confined to the ranks 
of the botanists; the evils here arraigned have long 
agitated zoologists as well. But the organisms botanists 
have to deal with are so different from animals, at least 
the higher forms of animal life, in methods of repro- 
duction, manner of growth, and response to environment, 
that the species problem in botany is a far more complex 
question to deal with than it is, for example, in the higher 
vertebrates, with which alone the writer claims famil- 
larity. 

Where to leave off naming ‘‘forms’’ is, after all, the 
main point at issue, and the next, how best to express 
their relationships as regards origin and degree of 
affinity. Utility should be, of course, the criterion in both 
cases, but especially in the former. How to designate the 
minor forms, and to what extent they may be profitably 
provided with names are questions that agitated zoolo- 
gists apparently long before they became serious prob- 
lems with botanists. Zoologists, certain of them at least, 
long since reached what seemed to them a satisfactory 
solution of the species question by recognition of the fact 
that ‘‘species,’’ like genera and the higher groups, have 
no real existence, but are merely man-made concepts, 
purely arbitrary and conventional, devised for conveni- 
ence in recording our knowledge of organic nature. More 
than thirty years ago this concept found practical recog- 
nition among American ornithologists and mammalogists, 
and from this hotbed of heterodoxy the infection rapidly 
spread until this point of view became the working basis 


594 THE AMERICAN NATURALIST — [Vow. XLII 


of their coworkers throughout the world. As early as 
1884 this postulate was incoroprated in the A. O. U. Code 
of Nomenclature (first published in 1886), as a reason for 
the adoption of trinomials, in the following words: 


Recognition of the scientific fact, that a “ species,” so-called, is not 
a fixed and special creation, as long supposed, but simply a group of 
the same intrinsic character as that called a genus, though usually less 
extensive, and always of a lower taxonomic rank, has done more than 
any other single thing to advance the science of zoology; for the whole 
theory of evolution turns, as it were, upon this point. 

Respecting the meaning and function of the trinomial 
system, it is said in the same connection: 

Trinomials are not necessarily to be used for those slightly dis- 
tinct and scarcely stable forms which zoologists are in the habit of calling 
“ varieties ”; still less for sports, hybrids, artificial breeds, and the like; 
nor indeed to signalize some grade or degree of difference which it may 
be desired to note by name, but which is not deemed worthy of a 
specifie designation. The system proceeds upon a sound scientific prin- 
ciple, underlying one of the most important zoological problems of the 

ay,—no less a problem than that of the variation of animals under 
physical conditions of environment, and thus of the origin of species 
itself. The system is also intimately connected with the whole subject 
of the geographical distribution of animals; it being found, as a 
matter of experience, that the trinomial system is particularly pertinent 
and applicable to those geographical “ subspecies,” “ races” or “ varie- 
ties” which have become recognizable as such through their modification 
according to latitude, longitude, elevation, temperature, humidity, and 
other climatic conditions. It is obvious, therefore, that the kind or 
quality, not the degree or quantity, of difference of one organism from 
other determines its fitness to be named trinomially rather than 
binomially. In a word, intergradation is the touchstone of tri- 
nomialism. 


A small amount of difference, if constant, was con- 
sidered ‘‘specific,’? in a proper sense, while a large 
amount of difference, if found to lessen and disappear 
„when specimens from contiguous faunal areas were com- 
pared, was considered as not specific! . 
ile these distinctions and principles have been 
found to work well in vertebrates, and have become to a 


*Cf. A. O. U. Code of Nomenclature and Check-list of North American 
Birds, 1st ed., 1886, pp. 27, 31, and context. 


No. 501] THE SPECIES QUESTION 595 


large extent the working basis of zoologists, it is evident 
that they must necessarily fail to meet the needs of 
botanists, where the minor differentiations are of such a ` 
different character, and where so many and such diverse 
conditions affect differentiation within groups formerly 
recognized as species. Botanical nomenclature evidently 
must remain a makeshift, satisfactory to no one, until the 
ecological, physiological and experimental botanists have 
come to a better understanding of the causes and rela- 
tions of morphological and physiological differences 
among closely related forms. ; 

The introduction of trinomial nomenclature into zo- 
ology, while satisfactory for the designation of inter- 
grading geographic forms, left still unsettled the old ques- 
tion of how far it is profitable to recognize in nomen- 
clature the minor morphologic differentiations. In the 
cases of mammals and birds it was found necessary to 
reduce many so-called species to subspecies, and also to 
add, as material increased, many new forms under tri- 
nomial designations. These were, of course, intergra- 
ding forms, and hence arose the serious question of where 
to stop bestowing names upon slight morphologic varia- 
tions, restricted to limited and not very clearly defined 
physiographic areas. As no hard and fast rule can be 
formulated, the treatment of such cases becomes largely 
a matter of temperament, experience and good judgment, 
in other words, the fitness of the taxonomer for his work. 
As is well known, the American Ornithologists Union has 
a permanent committee on the nomenclature and classi- 
fication of North Amrican birds, whose function it is to 
consider all proposed changes in nomenclature and all 
proposed additions to the list of North American birds. 
This committee, consisting of seven members, is reap- 
pointed annually, and is subject to change in personnel. 
Its reports are published from time to time in the form 
of supplements to the A. O. Check-List of North American 
Birds, in which are given not only the accepted changes 
of nomenclature and the additions to the list, but also 


596 THE AMERICAN NATURALIST [Vou. XLII 


briefly the reasons for not accepting certain of the pro- 
posed nomenclatural changes and additions. While, its 
authority is, of course, not final, except as regards the 
A. O. U. Cheek-List, it can throw the weight of its in- 
fluence against innovations that in its judgment are detri- 
mental to the best interests of the science. It un- 
doubtedly acts as a powerful deterrent upon ill-considered 
work, and the general acceptance of its decisions by 
amateurs and laymen tends to the conservation, in this 
country at least, of a standard and uniform honaino 
for North Amaroni ornithology. It is a mild form of 
censorship—far less radical and drastic than that pro- 
posed by some of the botanists at their recent Chicago 
meeting. 

As already said, the conditions in regard to the nomen- 
clature of minor forms which confront botanists are very 
different from those met with in the study of terrestrial 
vertebrates. There is no group in mammals, birds or 
reptiles comparable in respect to the number, character, 
and association of its minor forms with Crategus, Rubus, 
Aster, Sisyrinchium and numerous other botanical 
genera, where several recognizable morphologic forms 
occur in intimate geographic association. In the verte- 
brate classes named, the forms recognized in nomencla- 
ture that occupy the same area are always sharply sepa- 
rated; there is never a question of specific or even sub- 
specific identity, except in the case of migratory birds, 
where several different geographic subspecies may be 
found associated in migration, or during the non-breeding 
season, in districts remote from their respective breeding 
ranges. Questions of identification arise, not between 
locally associated forms, but in reference to whether in- 
dividuals from intermediate areas are referable to one 
or the other of the several subspecies that occur typically 
only in adjoining physiographic (faunal) areas. An ap- 
parent exception is afforded by the red crossbills (Loxia 
curvirostra group), where a wide range of so-called in- 
dividual variation is met with, affecting the general size, 


No. 501] THE SPECIES QUESTION 597 


to some extent the coloration, and especially the relative 
size and massiveness of the bill. The extremes of varia- 
tion in the latter are enormous for the size of the bird. 
As such individuals occur, however, more or less gen- 
erally throughout the exceptionally wide (almost con- 
tinental) range of the species, and are thus not char- 
acteristic of any particular locality or region, and also 
are everywhere associated with birds of intermediate 
characters, these divergent ‘‘forms’’ are not considered 
by ornithologists as entitled to nomenclatural recognition. 
Some years since a large-sized, large-billed, very red form 
was described as a subspecies under the name Loxia 
curvirostra bendirei, based on specimens from eastern 
Oregon. It was long held in abeyance, however, by the 
A. O. U. Committee, and finally rejected on the ground 
that no definite or distinctive geographic range could be 
assigned to it. 

This case is cited as an illustration of the wide differ- 
ences in conditions that obtain in botany and zoology. If 
the crossbills grew fixed to the soil like plants, and their 
ecology was equally open to investigation, some cause 
might be assigned for the development, respectively, of 
the large-billed and small-billed forms. At present all 
we know is that the common red crossbill is an exceed- 
ingly erratic species, nesting apparently with equal fre- 
quency in mid-winter or in summer, and migrating with 
extreme irregularity as to season and the regions visited, 
and characterized by an exceptionally wide range of 
morphologic variation. The variation in the general size 
of the individual, and in the size of the bill and in colora- 
tion may result from different food habits, and the lack 
of any sharply defined lines of morphologic separation 
may be due to frequent or habitual interbreeding of the 
different morphologic strains. The peculiar life habits 
and general economy of the species seem to hopelessly 
remove it from the field of experimental research, at least 
for the present. 

Considering utility as the test, the trinomial system 


598 THE AMERICAN NATURALIST [Vou. XLII 


fairly meets requirements in the case of the higher verte- 
brates; it seems to apply less satisfactorily in the lower 
animal phyla and in botany. It is admittedly preferable, 
however, in botany, in a large number of cases, to the 
binomial method, even where the variation is not geo- 
graphic, since it denotes close affinity and supposed an- 
cestry. The suggestion of Clements (l. c., pp. 262-264) 
that, where new names are required, the third term be 
chosen with reference to the nature and origin of the 
variant, seems to offer distinct advantages. 

It seems probable that the ‘‘species concept’ in 
botany, as in zoology, can be settled only by conventional 
agreement; and the many interests and the diverse fields 
of research to be considered and harmonized, seem to 
relegate this desirable event to the remote future. The 
present diversity of views respecting the desirability and 
the manner of designating minor forms does not forecast 
a speedy agreement on even this important phase of the 
subject. If ever agreement is reached it obviously must 
come about through concert of action and mutual con- 
cessions. No radical scheme of censorship should be 
seriously entertained; any attempt to restrain the exer- 
cise of individual judgment will be strenuously opposed. 
Each man’s work must stand or fall on its merits, in mat- 
ters of taxonomy as in other fields of scientific research; 
the insistence on Latin diagnoses is a step in the direction 
of medieval intolerance, and apparently had its origin in 
personal jealousies rather than in a desire to advance the 
true interests of science. The ability to write in a dead 
language is no measure of a man’s ability as a taxono- 
mer, nor of his scientific sanity, nor of his general level- 
headedness as a naturalist. As said by one of the par- 
ticipants of the symposium: 

“What constitute sufficient morphological characters [for a species 
or for a minor form] must be left to the individual judgment.” 


The proposition to recognize by name species only and 
to designate minor forms—the subspecies or ‘‘races’’— 


No. 501] THE SPECIES QUESTION 2 699 


numerically seems to have met with some degree of ap- 
proval; which is natural, since, at first sight, it seems to 
present some advantages. But ‘‘Quercus alba race 2,” 
or ‘‘Draba verna, race 104,’’ can mean little unless the 
authority for the race be added as ‘‘race 2 Brown,’’ or 
“race 104 Smith’’; since different authors may be at 
work almost simultaneously upon the same group, so that 
race 2 or race 10 of A may not be the race thus designated 
by B, who at the time was ignorant of what A had done. 
There would be under this new method the same oppor- 
tunity as at present for synonymy to play its usual rôle, 
the same necessity for the strict enforcement of the rule 
of priority. It is thus hard to see how the conditions 
would be improved by the adoption of a bare numeral in 
place of a name, which generally has some useful sug- 
gestiveness. If the authority for the race must be added 
to secure absolute definition, as would certainly be neces- 
sary in many instances, very little would be gained in 
point of brevity, and much lost in the way of aid to the 
memory. Should such a system be adopted and be made 
retroactive, chaos would hold place for an indefinite 
period, and the familiar verbal designations of the past, 
with their historic suggestiveness, would eventually share 
the fate of the designations of the herbalists of the past 
centuries. But there is probably little cause for alarm, 
since any serious attempt to introduce numerical designa- 
tions in place of trinomials must, in all probability, 
demonstrate their impracticability. The proposition is 
more novel than practical, a protest against burdensome 
conditions rather than a panacea. 
Another point brought out in this series of papers, 
though of perhaps no great importance, invites comment. 
It is stated (l. c., p. 246): 


“Tf I understand aright, the ornithologists, at least some of them, 
are willing to assert that species may differ by characters which can not 
be deseribed by words [laughter]; that is to say, you will know the 
species when you see it, but you can not describe it in any language 
by which another person may recognize it. I think that this is not a 


600 THE AMERICAN NATURALIST [Vou. XLII 


joke, but that it is really stated in earnest; because I read it in Science. 
[Laughter.] But I fancy botanists have not gone quite that far.” 

The author of this statement, which seems to have 
excited so much merriment, was simply mistaken. It 
would have had more basis if he had said subspecies, or 
‘‘forms,’’ instead of species, but even then would have 
been misleading and unfair. There are plenty of in- 
stances, among both birds and mammals, where local 
forms of a species are perfectly recognizable by any one 
as morphologically different when directly compared, 
through very obvious differences in coloration. But 
shades of color perfectly apparent to the eye are hard 
to characterize in language, from the fact that the color 
terms in current use are vague and uncertain, so that 
different persons may habitually describe the same tones - 
of color in different terms, and use the same phraseology 
for quite different tints. It is for this reason that direct 
comparison of specimens is so often necessary; not that 
the forms themselves are so difficult to distinguish. The 
statement that ‘‘botanists have not gone quite that far’’ in 
describing ‘‘forms’’ is hardly borne out by the confession 
of another participant in this symposium, who says (l. c., 
p. 240): 

“The general result of these attempts to dissect nature has been 
embarassing beeause when a subsequent student takes up the group 
he is wholly unable to determine from any descriptions that can be 
written where any given individual would have been grouped by the 
previous author, unless he has access to the actual specimens which the 
previous author studied,” ete. 


THE ORIGIN OF THE LATERAL OF VERTE- 
BRATES EYES 


PROFESSOR G. H. PARKER 


HARVARD UNIVERSITY 


Tue steps by which the vertebrate sense organs have 
arisen have been traced in some measure through the evi- 
dence afforded by their embryonic growth. In this re- 
spect few systems of organs are more homogeneous. It 
seems to be a well established principle of embryology 
that all the sense organs of a developing animal shall arise 
from its outermost layer of cells, the ectoderm, and the 
fact that sense organs are the chief means by which an 
animal tests its environment shows that the embryonic 
source of these organs is not without significance, for 
what situation is more important for organs adapted to 
the reception of environmental changes than the outer- 
most surface of the animal that possesses them. These 
conditions are well illustrated by most of the sense or- 
gans possessed by the vertebrates. Our organs of touch 
have for the most part remained where they were formed 
in the outermost layer of the skin. The internal ear, 
which in the great majority of vertebrates is a compli- 
cated sac without connections with the skin, is known to 
arise in individual development as a pocket from the skin 
secondarily cut off from that layer. Without doubt it is 
an excessively delicate organ of touch, for hearing and 
the other sensory activities of the ear seem to be depend- 
ent upon the same form of stimulus as touch, except 
that the kind of stimulus appropriate to the ear is much 
more refined than that for simple touch. Like the ear, 
the vertebrate organs of taste and of smell are also prob- 
ably derived from the skin and in their cases they still 
retain the primitive connections with the mother layer, 
for though they are in cavities, these cavities are lined 
with tissue directly continuous at the mouth of the cavity 

601 


602 THE AMERICAN NATURALIST [Von XLII 


with the skin. Thus, excepting the eyes, all the more ob- 
vious vertebrate sense organs show immediate and 
simple relations with the external layer, the skin. 

From this standpoint the lateral eyes of the vertebrate 
are by no means as simple as the other vertebrate sense 
organs. As has long been known the vertebrate retina, 
the essential nervous portion of the eye, does not arise 
directly from the external layer of the animal, but is an 
outgrowth from the brain. And though the brain arises 
by involution from the ectoderm and the retina may there- 
fore be said to come directly from that layer, the fact that 
the retina does not precede the brain in its development 
but at best differentiates at the same time with the brain, 
leaves the question of the exact origin of the retina in un- 
certainty. 

Not only is the vertebrate retina, unlike other verte- 
brate sense organs, not obviously connected with the 
external ectoderm, but it is also peculiar in the arrange- 
ment of its receptive cells, the rod- and cone-cells. In 
the great majority of sense organs, the receptive mech- 
anism is made up of cells with very marked polarity in 
that one end of the cell is differentiated as a receiving 
structure and is directed toward the impinging stimulus, 
and the other end either tapers into a fibrous process, the 
nerve fiber, or is in intimate relation with nerve fibers 
from other cell bodies. In other words, the sense cells 
are differentiated in that one end serves for reception, 
and the other for transmission, and the cell is so placed 
that the receptive end is nearer the source of the stimulus 
than the transmitting one. In the vertebrate retina this 
condition is reversed. The light that enters the eye falls 
first upon the transmitting ends of the sense cells and 
only after it has passed through these cells does it reach 
the receptive end. The vertebrate retina is, therefore, 
appropriately described as an inverted sense organ. 
Thus the vertebrate eye departs in two important partic- 
ulars from the other vertebrate sense organs: first, its 
sensory elements do not arise in any simple or direct way 


No.501] THE ORIGIN OF VERTEBRATE EYES 603 


from the outer ectoderm and, secondly, these elements 
are inverted in their relation to the stimulus. 

As a consequence of these peculiarities of the verte- 
brate retina numerous theories have been proposed to 
account for its present condition. It must be quite clear 
from what has already been stated, that the chances of 
a simple course of development for the vertebrate retina 
are not great, and the first theory to be considered em- 
phasizes this feature. This theory was first proposed 
by Sharp (1885); subsequently it was independently ad- 
vanced by Béraneck (1890) whose views were supported 
by v. Kupffer (1894) and especially by Burckhardt (1901). 
According to this theory the primitive vertebrate retina 
is what we now recognize as the lens. As is well known, 
this organ develops as a pocket of ectoderm in the region 
superficial to the forming eyeball. In its early stages, 
as v. Kupffer pointed out, it has a striking resemblance 
to the beginnings of the nose and the ear and its first 
steps of development recall those of the eyes of many 
invertebrates. This primitive retina is supposed by the 
advocates of this theory to be metamorphosed gradually 
into a dioptric organ and the deeper ganglionic parts are 
believed to assume receptive functions and thus establish 
a new retina from tissue that is an outgrowth from the 
brain. By this process of replacement the primitive 
retina is converted into a lens and a secondary retina 
established. It will be observed that while this theory 
offers an explanation for the lens and for the origin of 
the retina from a part of the central nervous system, it 
does not take into account that very striking character- 
istic of the vertebrate retina, its inversion. Not only is 
this theory thus defective, but any candid reviewer must 
agree, I believe, with Keibel that the resemblance that the 
vertebrate lens has to a sense organ is only of the most 
superficial kind and that when one attempts to picture the 
steps whereby a retina is to be converted into a lens and 
a ganglionic mass into a retina, the difficulties come to be 
almost insurmountable. For these reasons this theory 


604 THE AMERICAN NATURALIST  [Vou. XLII 


has found relatively few advocates and is regarded by 
many as wholly untenable. 

The second general theory, as to the origin of the 
vertebrate retina, is one which has much more in its favor 
and which is presented in as complete a form by Balfour 
(1881) as by any other. It has recently been independ- 
ently advanced by Jelgersma (1906). According to this 
view the vertebrate retina originated on the outer sur- 
face of the ancestral vertebrate in much the way that the 
eyes of many invertebrates have been produced. The 
primitive retinas thus formed were implanted in that por- 
tion of the surface of the animal from which the central 
nervous system was destined to develop and when this 
was infolded these retinas were carried in with it, and 
came thus to be involved in the central organ. If the 


Fic. 1. Imaginary transverse section through the head of a vertebrate 
embryo to show the morphological relations of the surfaces of the ectoderm of 
the integument, the medullary tube, and the forming retina. In each of these 
situations a single sense cell is indicated. 


morphological position of a sensory cell such as may 
have existed in the primitive external retina is supposed 
to have been retained as this organ was carried from its 
superficial location into the central nervous system and 
out again almost to the external surface, the resulting 
retina would be composed of inverted elements (Fig. 1). 
Thus this theory at once offers an explanation for the two 
most striking features of the vertebrate retina, namely, 
its formation as an apparent outgrowth from the central 


No. 501] THE ORIGIN OF VERTEBRATE EYES 605 


nervous system and the inverted condition of its receptive 
cells. 

The most obvious objection to this view is that the 
. retina must be supposed to be a functional organ during 
this whole process of migration and inversion. But this 
objection, as others have already pointed out, is not 
serious, for if we imagine these processes to take place 
in animals like certain pelagic tunicates or even amphi- 
oxus, the transparency of the body would be such as to 
offer no hindrance whatever to the continuous action of 
such an organ even when in its deepest position. From 
this standpoint, therefore, there is no serious objection 
to the theory as already outlined. 

The various adherents of this theory have differed con- 
siderably as to the details of its application. The gen- 
eral account of it already given is the particular form 
which was advocated by Balfour (1881) and which has 
since been revived by Jelgersma (1906). Balfour makes 
no mention of any living animal that might be taken to 
represent, according to this theory, a stage in the evolu- 
tion of the eye. Von Kennell (1881) designated the 
annelids as probable ancestors and attempted to show 
how the external eyes of these worms could be converted 
into the type of eye found in the vertebrates. Jelgersma 
on the other hand has accepted amphioxus as an inter- 
mediate form and has based his description of the evolu- 
tion of the eyes on the conditions found in this animal. 
These three investigators agree in believing that the 
vertebrate eyes have arisen from optic organs that were 
once on the exterior of an ancestral form. Lankester 
(1880) and Boveri (1904), however, do not place the 
origin of the eye in so remote a region but believed that 
it arose in the central nervous system in such a place as 
is now occupied by the eye of the ascidian larva (Lankes- 
ter) or the numerous eyes of amphioxus (Boveri). In 
this way these two investigators abandon some very sig- 
nificant parts of the Balfour theory but in other respects 
they follow it very closely. 


606 THE AMERICAN NATURALIST [Vou. XLII 


Whether we accept the annelids, or amphioxus, or still 
other animals as representatives of the ancestors of the 
vertebrates, we shall find it necessary, according to the 
Balfour theory, to assume some intermediate form in 
which the eyes are so located as to represent a condition 
between a primitive integumentary eye and one such as 
is possessed by the true vertebrates. Such a condition 
occurs apparently only in the minute larve of the 
ascidians and in amphioxus. As very little is known 
about the actual conditions in the ascidians in this re- 
spect, we shall turn our attention to the optic organs of 
amphioxus. 

Great diversity of opinion has been expressed as to the 
parts of amphioxus that are sensitive to light. From 
recent experimental work, however, it may be taken as- 


. 2. Transverse section of the nerve obra of amphioxus, IE three 
direction eyes in place. Modified from Hes 


fairly well established that the so-called eye-spot at the 
anterior end of the nerve tube and the integument of 
amphioxus are not sensitive to light, but that the small 
pigment cups described by Hesse (1898) as photo-recep- 
tive organs and found through almost the whole length 
of the nerve tube are the true visual organs. They lie 
in the substance of the nerve tube and though they have 
not been regarded by Hesse as in any way connected 
with the vertebrate eyes, they occupy a position that is 
very suggestive of a stage intermediate between an ex- 
ternal eye and one such as the vertebrate now possesses. 


No.501] THE ORIGIN OF VERTEBRATE EYES 607 


Viewed from this standpoint the optic cups of amphi- 
oxus are not without interest. They can be seen well in 
any transverse section of the nerve tube of this animal 
(Fig. 2) provided the section is not taken from a part 
of the body too far toward the anterior end. In such a 
section the cups will be found close to the central canal. 
Each cup is made up of a concave pigment cell in the 
hollow of which is a fan-shaped cell. The expanded end 
of this fan-shaped cell fills the pigment cup while the 
handle of the fan tapers off into a nerve fiber. The 
whole structure, as Hesse observed, has a most striking 
resemblance to the simple direction eye of certain planar- 
ians, and it is difficult to resist the conclusion that amphi- 
oxus is an animal whose nerve tube is richly provided 
with a simple type of direction eye. 

If these bodies in the nerve tube of amphioxus are 
direction eyes, their positions are not without significance. 
On examining a number of transverse sections in which 
they occur, it will soon be recognized that their arrange- 
ment is any thing but regular. Most of them are directed 
either dorsally or ventrally, but almost any position may 
be assumed. Though they le near the central canal, 
they are not arranged in reference to it with any de- 
gree of uniformity. Some point away from it, others 
toward it. 

The lack of uniform arrangement shown by these visual 
cups is of considerable importance in relation to Bal- 
four’s theory of the origin of the retina. If this theory. 
is correct, the inversion of the retina is dependent upon 
a rigid orientation of the sensory cells which is supposed 
to have been retained absolutely from their place of 
origin of these cells in the external skin, through every 
step in their migration to their final position in the com- 
pleted retina. If once in the course of this migration 
orientation is lost, the mechanism fails. Since amphioxus 
is the only animal that represents well an intermediate 
stage in this process, and since in amphioxus the orienta- 
tion is lost, it seems to me that Balfour’s explanation 


608 THE AMERICAN NATURALIST [Von XLII 


falls to the ground. I, therefore, do not believe that the 
vertebrate retina is inverted because it has been inherited 
from an integumentary source, and I agree with Boveri 
` that the condition in amphioxus removes all occasion for 
the assumption that the vertebrate retina arose on the 
exterior of an ancestral form and became deep-seated by 
being involved in the developing central nervous system. 
That the central organs should thus become a seat for the 
origin of essentially sensory mechanisms is not surpris- 
ing as long as such an appropriate stimulus as light can 
in certain cases reach them. Even in our own bodies the 
respiratory reflex is maintained through the direct stimu- 
lation of the medulla by the blood that passes through 
it, an operation the first step of which must be equivalent 
to the process of sensory stimulation. 

I know of no reason for assuming that the visual appa- 
ratus of amphioxus arose in any other than its present 
position, and I believe there is good grounds, as Boveri 
has pointed out, for the opinion that the visual cells of 
amphioxus are the homologues of the rod- and cone-cells 
of the vertebrates. These visual cells then probably 
represent the material out of which the vertebrate retina 
has been made. If this is true why have the eyes of ver- 
tebrates developed where they have and how does it come 
that their retinas are inverted? 

An answer to the first of these questions can be found, 
I believe, in the size of the vertebrate body as compared 
with that of such an animal as amphioxus. In amphioxus 
the body is so small and thin that it is sufficiently trans- 
parent to allow light to penetrate it anywhere. Hence 
visual organs may be functional at any point along the 
length of its nerve tube. In most fishes, however, the in- 
crease of size has involved such a development of the 
body musculature that the posterior part of the nerve 
tube, the spinal cord, is completely buried in thick, almost 
opaque tissue. Hence visual cells would no longer be 
serviceable in such a region as this and they have doubt- 
less thus been restricted to what has become the brain 


No.501] THE ORIGIN OF VERTEBRATE EYES 609 


region of the nerve tube. Furthermore in the brain 
region the development of the musculature for the gills 
and jaws together with the growth of the cranium as a 
support for this musculature must have cut off the light 
from below. Hence the natural growth of the body of 
the fish would tend to restrict the occurrence of the visual 
cells to the sides of the anterior end of the nerve tube, 
the regions from which the eyes of the vertebrates de- 
velop. It is in this partial envelopment of the nerve 
tube with somewhat opaque tissue that, in my opinion, 
has limited the eyes of vertebrates to their present posi- 
tions. 

An answer to the second question raised, namely, why 
is the vertebrate retina inverted, is found, I believe, in 
the structure of just such direction eyes as amphioxus 
possesses. The visual cell in each of these eyes has its 
receptive end buried in the depths of its pigment cup and 
its fibrous end directed outward through the open mouth 
of this cup. As the effective light necessarily enters the 
cup through its mouth, the visual cell is inverted in its 
relation to this stimulus. If then we imagine a retina to 
be formed from a great aggregation of individual direc- 
tion eyes of the type found in amphioxus, it follows that 
the receptive elements of such a retina would be inverted. 
This, in my opinion, is the reason for the inversion of the 
receptive cells in the retina. The vertebrate retina then 
is fundamentally unlike the other vertebrate sense or- 
gans in that it is not directly derived from the external 
ectoderm, but is developed as a part of the central ner- 
vous system, and its inversion is dependent upon its 
origin from an aggregation of direction eyes each one of 
which was of necessity inverted from the beginning. 


NOTES AND LITERATURE 


HEREDITY 


Spurious Allelomorphism: Results of Some Recent Investiga- 
tions.—The original conception of a Mendelian character pair was 
that of two antagonistic characters, one of which dominates the 
other in such a way as to prevent the development of the other 
in individuals inheriting both characters, the anlagen of the two 
being so related to each other in the mechanism of the cell that 
the pair separates in the reduction division. This conception has 
recently been modified by leading Mendelian investigators so that 
now a Mendelian pair is looked upon as presence and absence of 
a particular Mendelian character, presence being dominant to 
absence. There are some apparent exceptions to this rule of 
dominance, but they are probably only apparent. 

Some recent investigations indicate that we must still further 
modify our conception of pairs of hereditary characters. 
Bateson was the first to call attention to a caset which he later? 
terms spurious allelomorphism. It is a case in which two domi- 
nant characters behave in transmission as a character pair. 
i. e., they are alternative in transmission—they can not be trans- 
mitted by the same parent to a single offspring. Perhaps, at 
the outset, we should broaden this conception a little so as to 
provide for the pairing of any two physiologically unrelated 
characters, whether dominant or recessive. A suitable term to 
designate such pairs is needed. The term appomorphs would 
answer the purpose very well were it not for the more or less 
arbitrary rule of philological fashion that hybrid words are not 
permitted, The first two syllables of this word are Latin, and 
contain the idea of apposition—the two characters are apposed 
in the reduction division. The last syllable is Greek. Possibly 
a hybrid word may be permitted in dealing with hybrids unless 
a good “‘pure-bred’’ word can be found. 

The first case to which Bateson called attention was that of the 
erect standard and blue flower color in sweet peas. These two 

* Science, November 15, 1907. 

2 Science, May 15, 1908. 

* Science, November 17, 1907. 

610 


No. 501] NOTES AND LITERATURE 611 


characters form an alternative pair in the plants with which he 
dealt. Bateson calls attention to the interesting fact that both 
are characters of the wild sweet pea. Assuming that in the wild 
species these characters are transmitted together, we must further 
assume complete correlation between them; the complex pair 
thus being blue flowers and erect standard paired with blue 
flowers and erect standard. The cultivated forms have thus 
arisen by the loss of erect standard in one member and of the 
blue factor in the other, leaving the pair consisting of blue flowers 
on the one side and erect standard on the other. This may be 
clearer if we express it in formule. Let B= the blue flower 
factor, and E the erect standard. In the wild pea we have 
BE — BE as the pair of correlated characters, while Be — bE is 
the form assumed by this pair in the cultivated forms. 

The next case of spurious allellomorphism was also found by 
Bateson,* while studying some extraordinary results obtained by 
Doncaster and Raynor in breeding certain moths (Abrazas 
grossulariata and its var. lacticolor). If we let G stand for the 
character in which the species differs from the variety, and L 
for the corresponding character in the variety, the results to be 
explained may be stated as follows: 

1. 9L X gG gives only 9G and gG (No L). 

2. 9G X gL gives only 9L and gG. 

Furthermore, when the male used is a product of either of the 
above crosses, then | 

3. 2G X GG gives FL, 9G, JG, but no gL. 

4. QL X GG gives FL, 9G, ZL and JG. 

The following explanation of these phenomena is not given in 
Bateson’s terminology, which seems to the writer to be needlessly 
involved, but it is based on Bateson’s explanation. 

Let F =the female character and f its absence. 

Let G = grossulariata character and g its absence and assume 
that F and G are allelomorphie to each other. 

Result No. 1 above now becomes Fg X GG—=FG-+ GG, or 
female G and male G. 

No. 2 becomes FG X gg — Fg + Gg, or female L and (hetero- 
zygote) male G. 

No FGX Gg = FG + Fe + GG + Gg, or female G, 
female L, and male G. 

No.4. Fg X Gg = FG + Fg + Gg + gg, or female G, female 
L, male G, and male L. 

* Science, May 15, 1908. 


612 THE AMERICAN NATURALIST [Vot XLII 


It is noteworthy that the male lacticolors produced in these 
experiments were the first known, all known specimens of the 
variety having been females. The reason for this is not far to 
seek. Male L’s occur only when female L’s mate with hetero- 
zygote males. The latter arise (from G parents) only in those 
matings which produce female L’s (see mating No. 4 above). 
Heterozygote males are therefore as rare as female L’s. If 1/n 
of the female population is L, then 1/n of the male population is 
heterozygote. The chance that these two shall mate is therefore 
1/n X 1/n = 1/n?. Hence, if only 1 female in 1,000 is L, only 
one male in 1,000,000 is L, which probably accounts for their 
having eseaped the collector. 

In the above case the female sex character seems to be paired 
with G. This is indeed a highly interesting fact, if true, and 
the results of Doncaster and Raynor leave little room for doubt 
that it is true. It now seems probable that sex is a property of a 
particular chromosome.’ If this is the case, then the G character 
should also belong to a particular chromosome. 

Bateson® also calls attention to what appears to be a similar 
ease of allelomorphism between the sex character and a color 
element, in the case of black pigmentation of silky fowls, when 
erossed with Brown Leghorns or other fowls with light shanks. 

I desire now to eall attention to a similar case that has come 
under my own observation. It is well known to breeders of 
Barred Plymouth Rock fowls that an occasional black bird crops 
out in this breed, and that these blacks are invariably females. 
Mr. J. F. Spilman, of Wentworth, Mo., tells me that he once 
erossed some Black Langshan males on his Barred Rock females 
with the result that in the progeny all the females were black 
and all the males barred. I have also seen, at the Mississippi Ex- 
periment Station, some crosses between Barred Rocks and Indian 
Games in which part of the progeny was black, the remainder 
being barred. Unfortunately, in this case, no observations were 
made as to a possible relation between color and sex. While the 
data just given are insufficient to establish beyond question the 
following explanation, the explanation is given in the hope that 
it may stimulate investigation on this point. Let us suppose 
that the female sex character (F) is paired with the barring 
element (B). Let f— absence of F and b= absence of B. 
Then a cross between a female Barred Rock and a male Black 

5 See remarks by Bateson, l. c. : 


No. 501] NOTES AND LITERATURE 613 


Langshan becomes FB X bb == Fb +Bb, or black (non-barred) 
females and barred males, as in J. F. Spilman’s experiment. It 
may be plainer to some if we write the above Fb — Bf X fb — 
fb — Fb — fb + fB — fb. 

Here F is correlated with b, and f with B; that is, in terms 
of the chromosome theory, the chromosome which carries F does 
not carry B, and vice versa, though these two chromosomes unite 
in synapsis to form a bivalent chromosome. 

The origin of black females from barred parents is, under our 
theory, the result of mating a barred female with a heterozygote 
male; thus: FB X Bb = FB + Fb + BB + Bb. 

This mating gives half of the females black, the other half and 
all the males being barred. 

But if we mate a homozygote male barred bird with a non- 
barred female (carrying black color of course), we get BB X 
Fb= FB + Bb, both sexes being barred. 

The result of this last mating has not yet been demonstrated. 
The same is true of the next mating, between a heterozygote 
barred male and a non-barred female, which should give 
Bb X Fb — FB + Bb + Fb + bb; that is, half of each sex 
black. : 

Some similar relation undoubtedly exists between a color ele- 
ment and the sex element both in geese and in ducks, for there 
are certain breeds of geese in which the males are all white and 
the females all colored; while in ducks certain breed crosses give 
the males all of one color and the females all of another. 

Two very interesting cases of allelomorphism between two 
physiologically unrelated characters are found in the recently 
published work of Noorduijn on ‘‘ Inheritance in Canary Birds.’”* 
The data given are not quite full enough to permit their complete 
elucidation, but they indicate clearly a pairing of the sex ele- 
ment (female) with yellow coat color, and also with a factor of 
the compound (from the Mendelian standpoint) eye color. 
There are three principal colors in canaries, namely, yellow, cin- 
namon (brown), and green. Since mating yellow and cinnamon 
always gives green birds (usually variegated, but part of the 
body green) we may infer that the green color arises from the 
combination of yellow and cinnamon, or of characters correlated 
with these. Noorduijn states that there are three pigments in 
the feathers of green canaries, namely, yellow, brown and black. 


°C. L. W. Noorduijn, in Arch. f. Rass-. u. Gesell.-Biol., April, 1908, 
p. 162 et seq. 


614 THE AMERICAN NATURALIST (Vou. XLII 


In a letter to the writer he states that in a solution of potash 
the yellow pigment disappears very quickly, the brown some- 
what slowly, while the black disappears only after a much longer 
interval. My interpretation of Noorduijn’s results is that yellow 
and cinnamon color characters in canaries are probably simple 
Mendelian characters (unit characters), while black is due to the 
meeting of two Mendelian factors one of which is correlated with 
cinnamon and the other with yellow. The case is probably more 
complex than here indicated, for some of the results indicate the 
presence of factors in addition to those here assumd. The prin- 
cipal results can now be explained by assuming that C (cin- 
namon or brown) and Y (yellow) are independent of each other, 
and that the female sex element (F) is paired with Y. Noor- 

duijn’s four cases are: 
I. C3 X G (green or green variegated) females gives Gg 
and C9. This cross sometimes gives G9’s but never Cg. 

II. G8 X C9 gives both sexes G. 

II. C3 X YQ gives GJ and C2. Also sometimes GF but 

never 

IV. Yg X C9 gives both sexes G. 

In the above no account is taken of variegation, which Daven- 
port has shown to be itself a Mendelian character.” The Mende- 
lian formule for Noorduijn’s four cases now become (remember- 
ing that when C and Y occur in the same bird the color is green 
or green variegated). 

I. CCyy X CCFy = CCFy + CCYy. 
Ce Gd 


II. CCYY X CCFy = CCFY + CCYy. 
Ge Gg 
III. CCyy X eeF'Y — CeFy + CeYy. 
C2 G 


i 
IV. ecYY X CCFy = CeFY + CeYy. 
G9 Gg. 

This does not account for occasional green females from crosses 

I and III, from which fact additional factors not here considered 
are indicated; but the formulæ indicate quite clearly that the 
sex element is paired with yellow coat color, or possibly with one 
faetor of this color. This assumption is confirmed by Noor- 
duijn’s statement that yellow males tend to impress their color 
*C, B. Davenport. Inheritance in Canaries. Carnegie Institution, 1908. 


a 


No. 501] NOTES AND LITERATURE 615 


more than yellow females. According to our assumption this 
should be the case, since yellow males transmit yellow to all off- 
spring, while yellow females transmit yellow only to their male 
offspring. 

That one factor of the eye color in canaries is allelomorphic to 
the female sex element is also clearly indicated by Noorduijn’s 
results. He gives only a meager portion of his experimental 
results on this point, so that the phenomena can not be explained 
here. There is enough to indicate that the case involves at least 
three independent Mendelian factors, one of which is correlated 
with yellow coat color, and hence allelomorphic to the sex ele- 
ment. 

W. J. SPILLMAN. 


HUMAN ANATOMY 

Sexual and Family Variation in Centers of Ossification.—Dr. J. 
W. Pryor, professor of anatomy and physiology at the State 
University, Lexington, Kentucky, for several years has been 
carrying on an investigation of the ossification of the bones of 
the human carpus, by means of X-ray photographs. He has 
made a study of over 550 hands, of which 266 were those of girls 
and 288 those of boys. In numerous instances he has examined 
the hands of the same individual at different periods, and has 
also made a study of the ossification of the bones in children of 
one family compared with those of other families. In a recent 
article in the Bulletin of the State University, Lexington, Ken- 
tucky, April, 1908, he has summed up some of the conclusions 
arrived at in previous publications, and has ught forth new 
material in confirmation of his more important generalizations. 
He finds centers of ossification appear earlier and develop faster 
in the bones of the female than in those of the male, and that 
this difference is measurable in infancy by days, in early child- 
hood by months, and later by years. The bones of the first child 
will, as a rule, ossify sooner than those of subsequent children of 
the same parents. There is considerable difference in the chil- 
dren of different families in the period when centers of ossifi- 
cation appear, but within a given family there is, as a rule, con- 
siderable similarity. Variation in the ossification of bones is an 
heritable trait. The studies of Professor Pryor enable him to 
give a more accurate table than has hitherto existed of the period 
when the centers of ossification appear in the carpal bones, The 


616 THE AMERICAN NATURALIST [Von. XLIT 


following table is copied from his last paper (Bulletin of the 
State University, Lexington, Kentucky, April, 1908) to illus- 
trate the rather remarkable difference in the time of the ap- 
pearance of the centers of ossification in the male and female 
hand 


TIME OF APPEARANCE OF CENTERS OF OSSIFICATION IN THE BONES 
F THE CARPUS 

Female: between the third and sixth month. 

Male: between the fourth and tenth month. 


1. Os Magnum 
(capitatum) 


bo 


Female: between the fifth and tenth month. 
Male: between the sixth and twelfth month. 


. Uneiform 
(hamatum) 


ow 


. Cuneiform 
(triquetrum ) 


Female: between the second and third year. 
Male: when about three years of age. 


a 


. Semilunar 


Female: between the third and fourth year. 
ae ge. 


Male: when about four years of age 


o 


Female: at four years of age, or early in fifth year. 
Male: when about five years of age. 


6. Trapezoid | Female: between the fourth and fifth year (preceding 


mas 


pezium). 
ao em Male: between fifth and sixth year (preceding tra- 
pezium). 


Female: between fourth and fifth year (preceded by 
Trapezoid). 

Male: between fifth and sixth year (preceded by tra- 
pezoid). 


ci E TE 
(multangulum 
minus) 


le: between the ninth and tenth year. 


ema 
8. Pisif 
ga Male: between the twelfth and thirteenth year. 
C 


PLANT CYTOLOGY 
Cytological Studies on Saprolegnia and Vaucheria.— These inter- 
esting and important types have been the subject of several in- 
vestigations dealing with the processes of oogenesis, fertilization, 
ete., with conclusions at variance in a number of fundamental 
points. Two papers have recently appeared which should re- 
ceive careful attention. 
laussen* reports upon oogenesis and fertilization of Sapro- 
legnia monoica, contributing important evidence on points under 
dispute through the investigations of Trow and Davis, and pre- 
1 Claussen, P. Ueber Eientwicklung und Befruchtung bei Saprolegnia 
monoica. Ber. d. Deut. Bot. Gesell., XXVI, p. 144, 1908. 


No. 501] NOTES AND LITERATURE 617 


senting a very different account and interpretation of the process 
of oogenesis. 

There is a stage in oogenesis, before the eggs are developed, 
when the protoplasm forms a peripheral layer enclosing a large 
region free from protoplasm in the interior of the oogonium. 
Other authors have believed this region to be a space containing 
cell sap, and developed by the gathering and flowing together of 
vacuoles in the center of the oogonium. Claussen describes the 
accumulation within the oogonium of a slimy substance which 
he believes to be derived from the degeneration of the cytoplasm. 
This cytoplasmic degeneration is conceived as proceeding out- 
ward until finally the protoplasm lies as a relatively thin layer 
in the ferm of a hollow sphere under the oogonium wall. The 
well-known nuclear degeneration accompanies, according to 
Claussen, that of the cytoplasm until relatively few nuclei remain 
in the peripheral layer. This account of an extensive cyto- 
plasmie degeneration to form a region filled with slime in a 
living active cell is not paralleled, so far as the reviewer is aware, 
in any cytological studies upon plants, and is likely to require 
more detailed study of a microchemical character before it will 
be accepted. 

Claussen is convinced in agreement with Davis that there is 
only one mitosis in the oogonium and not two mitoses with 
chromosome reduction as reported by Trow. This is an impor- 
tant point, since Trow’s view of chromosome reduction during 
oogenesis is contrary to the rule among plants that the processes 
of gametogenesis are unaccompanied by chromosome reduction. 
The species of the Saprolegniales which are sexual probably 
reduce the chromosome number (doubled by the fertilization of 
the egg) with the germination of the oospore; the apogamous 
species never have the double number, since the eggs develop 
parthenogenetically. 

The account of nuclear structure, the mitosis, and their sig- 
nificance for the processes of oogenesis presents a point of view 
entirely different from both Davis and Trow. Claussen reports 
a central body in the resting nucleus and at each pole of the 
intranuclear spindle. He believes that these establish a nuclear 
structure with polar organization similar to that of Phyllactinia 
as described by Harper (see review in the July number of the 
NATURALIST), but on account of the small size of the nucleus the 
behavior of this central body was not studied in detail. Each 


618 - THE AMERICAN NATURALIST [Vou. XLII 


daughter nucleus following the mitosis is accompanied by such a 
central body,or centrosome, with delicate protoplasmic radiations ; 
the greater number of these daughter nuclei degenerate. The 
cytoplasm begins to gather around those which survive, and such 
regions become the egg origins. Each egg origin has then in its 
interior a nucleus accompanied by a central body with radiations 
that extend outward in all directions through the cytoplasm. 
There is finally a cleavage of the cytoplasm between the egg 
origins and a rounding up of the protoplasm of each to form 
the egg. 

The central body of Claussen with its radiations is very con- 
spicuous at certain stages of oogenesis. Davis believed the struc- 
ture to be analogous to the coenocentrum of the Peronosporales 
and to be developed in the cytoplasm without genetic relation to 
the nucleus. Trow described asters associated with the surviving 
nuclei of the oogonium and believed them to be accompanied by 
deeply staining material constituting a body called by him an 
ovocentrum. The coenocentrum of Davis corresponds to the 
ovocentrum and egg aster of Trow and to the central body with 
radiations of Claussen. The views of Claussen are very inter- 
esting and the theory is logical, but his observations on the cen- 
tral body are not sufficiently detailed to establish fully his con- 
clusions. The nuclei of the Saprolegniales and Peronosporales 
have been studied by a number of competent observers who have 
failed to find a polar organization. However, these nuclei are 
small and the problem difficult, and further investigation may 
establish nuclear polarity in these groups of fungi similar to that 
in the Ascomycetes as determined by Harper. Should such 
evidence be forthcoming, the subject of nuclear structure and 
behavior in the Phycomycetes will take on an entirely new aspect 
of great significance in the explanation of the processes of 
gametogenesis and fertilization. 

Claussen finds that the eggs of Saprolegnia monoica are fer- 
tilized, thus adding another form to Trow’s list of sexual species, 
and it seems clear that fertilization occurs for a number of 
species in this group of fungi which is so largely apogamous. 
There is a single mitosis in the antheridium, with radiations 
around the central bodies less evident than in the oogonium. 
The antheridial tubes on entering the oogonium may apply 
themselves directly to the egg, but more frequently the ends 
branch and their tips become applied to several eggs. Finally 


No. 501] NOTES AND LITERATURE 619 


the end of such a tip opens and a sperm nucleus enters the egg, 
passing quickly to the female nucleus, which lies in the center 
and is without an evident central body. The sperm nucleus 
increases in size until the two fusing gamete nuclei become indis- 
tinguishable. The mitoses of oospore germination were not 
observed. Claussen found no bi- and tri-nucleate eggs in Sapro- 
legnia monoica as were reported by Davis for an apandrous 
form of Saprolegnia miata. 

Studies on several species of Vaucheria by Heidinger? are 
reported in a lengthy paper by Heidinger on the development 
of their sexual organs. The investigation was conducted in the 
laboratory of Oltmanns and centers around the disputed point 
as to how the mature oogonium with its one egg comes to contain 
a single nucleus, when the young oogonium is multinucleate. 
Oltmanns described the migration or withdrawal into the main 
filament of all of the numerous nuclei present in the young 
oogonium with the exception of one, which remained to become 
the nucleus of the egg. Davis holds that the young oogonium 
is multinucleate even after the formation of the cross wall, 
separating it from the parent filament, and that there is a process 
of nuclear degeneration during which all break down with the 
exception of a single surviving nucleus that comes to lie in the 
center of the egg. 

Heidinger’s conclusions are in agreement with the views of 
Oltmanns. All of the numerous nuclei except the future egg 
nucleus are said to leave the developing oogonium and to pass 
back into the parent filament before the appearance of the cross 
wall which separates the oogonium from the parent filament. 
Heidinger finds no process of nuclear degeneration as described 
by Davis. The egg nucleus, which remains after the process of 
nuclear migration, lies at first at the tip of the oogonium and is 
accompanied by a centrosome-like body, with protoplasmic radia- 
tions, similar to the central body described by Claussen for the 
eggs of Saprolegnia; shortly before fertilization this nucleus 
passes to the center of the egg. 

e paper gives many details of the series of events during 
the period of fructification and describes interesting culture 
methods. The cytological account is, however, open to criticism. 
The fixation was in ¥-1 per cent. chrom-acetic acid, a very 

*Heidinger, W. Die Entwicklung der Sexualorgane bei Vaucheria. 
Ber. d. Deut. Bot. Gesell., XXVI, p. 313, 1908 


620 THE AMERICAN NATURALIST (Vou. XLII 


strong fluid for such delicate algæ, and there was evidently much 
shrinkage of the material, as shown in the outlines of the text 
figures. These latter are not satisfactory, considering the impor- 
tance of the details which are discussed, and in the opinion of 
the reviewer are not convincing. There are some fundamental 
principles concerned in the discussion between Oltmanns and 
Davis which will require more thorough investigation before final 
conclusions are likely to be reached. The most important of 
these concern the history of the developing oogonium after the 
multinucleate stage, and the factors that lead to the selection 
of the nucleus which comes to preside over the egg. 
Brapuey M. Davis. 


HOLOTHURIANS 


Holothurioidea.1— Under the above title Ostergren has made a 
noteworthy contribution to the literature concerning the Holo- 
thurioidea. Based upon years of special study of the group, he 
concludes that in order to estimate the value of an organ in 
taxonomy and phylogeny, the function of the organ must be 
completely understood. 

Ostergren first discusses respiration, particularly in connec- 
tion with the enteron as respiratory organ. By means of their 
dilator muscles, sometimes the cesophagus, but most often the 
cloaca, functions as a pump to force the water into other parts 
of the enteron, or into especially developed extensions of the 
same. The primitive condition is found in the Synaptide. 

In most of the Elasipoda respiratory trees are lacking, and 
yet the cloaca is provided with dilators, and doubtless functions 
as a pump to force water into the enteron. As Ludwig (1889- 
92) points out, in various members of the Elpidiide and Psy- 
chropotide, a simple unpaired evagination appears as a ‘‘rudi- 
mentary gill,” or water-lung. From such a beginning comes 
the single, or double, stemmed respiratory trees. Since it is 
possible to have within a natural genus certain species without 
water-lungs, others with them rudimentary, and still others with 
well-developed respiratory trees, Ostergren maintains that the 
presence, or absence, of these organs is of no particular impor- 
tance in taxonomy. 

1 Östergren, Hjalmar. Zur Phylogenie und Systematik der Seewalzen. 


Särtryck ur Zoologiska Studier tillägnade Professor T. Tullberg. Upsala. 
October 12, 1907. 


No. 501] NOTES AND LITERATURE 621 


The pedicels have not the same importance for locomotion in 
sea-cucumbers as in sea-urchins and star-fishes. The sea-cucum- 
ber moves by worm-like contractions of the parts of the body. 
The pedicels on the part temporarily at rest either suck hold of 
the solid bottom or bore into the slime, and thus serve to give 
a firm basis from which the other parts of the body may be 
extended. Ostergren (1897) proves that the anchor-like spicules 
of the Synaptide are locomotor. Even in the pedate holo- 
thurians, the spicules help to make a firm anchorage for the 
resting part of the body while the moving part is bent away 
from the bottom and thus the rough points made by the spicules 
do not hinder the forward movement. Some sea-cucumbers, 
like the remarkable Pelagothuria, swim, and in them the pedicels 
are small and weak. 

On the other hand, the Dendrochirote#, which remain for a 
long time in one spot, have well-developed pedicels so that they 
can suck fast to rocks, or algæ, or on soft bottom, burrow into 
the slime and by means of their suckers ballast themselves with — 
stones and fragments of shells. The pedicels often gather weeds 
and shells which form a protective mask. In holothurians with- 
out pedicels, the spicules serve for this protective function. In 
very different groups spicules of the same form, albeit actually 
fundamentally different, may be developed without indicating 
any natural relationship of the groups. Such, for instance, are 
the anchors of the Synaptide, and the Molpadiide. The branch- 
ing of the calcareous rods is always in a manner best adapted 
to form the spicule with economy of material. 

While admitting that pedicels and tentacles are homologous 
as external appendages of the ambulacral system, Ostergren 
claims that they are distinctly different, with no connecting links 
between, and therefore, like Perrier (1902), declines to follow 
Ludwig’s (1889-92) characterization of the Synaptide as having 
tentacle-feet, and no body-feet. On the other hand, he does not 
follow Perrier in classifying the Molpadiide as apodous, but 
considers the anal papille as reduced pedicels which, like sim- 
ilar appendages in the Aspidochirote and Dendrochirote, have 
evolved as tactile organs. 

Ludwig (1891) proves for one of the Dendrochirote, Cucu- 
maria planci, and the present writer has shown (Edwards, 1889, 
1905) for one of the Aspidochirote, Holothuria floridana, that 
the tentacles develop from the radial canals in the same manner 


622 THE AMERICAN NATURALIST [Vou. XLII 


as the pedicels. Furthermore, in Holothuria floridana at first 
the tentacles are provided with terminal suckers and these organs, 
like the primitive pedicels, are used for locomotion, while in 
feeding, as in the adult, they push food into the mouth. Admit- 
ting that the distal anal papille are modified pedicels, I think it 
is reasonable to consider the proximal oral tentacles as pedicels, 
only much more modified in the adult, for their special functions. 

Östergren imagines the primitive form, or ‘‘Stammholothurie,”’ 
as having had a soft body-wall containing spicules, and with five 
simple radial muscle bands, interrupting the transverse sheet of. 
muscle. It moved by contractions of the body, and ate slime. 
The stone-canal was simple and opened on the outside of the 
skin. There were many pedicels and either ten or twenty ten- 
tacles without ampulle. The calcareous ring had five radialia 
and perhaps five interradialia. The enteron was in three loops, 
the third in the right ventral inter-radius. The blood system 
did not expand into a rete mirabile. The posterior end of the 
enteron developed as a respiratory cloaca but respiratory trees 
were not present. There were no auditory vesicles. Ostergren’s 
primitive form was most nearly related to the present Elasipoda, 
and from it he shows how the five chief divisions of the class 
Holothurioidea may have evolved. Ostergren employs as the 
names of these orders, Elasipoda, Aspidochirota, Dendrochirota, 
Molpadonia and Apoda (Synaptide, Chiridotide and Myrio- 
trochide), and then concludes with a general description of the 
chief characters of each order. 

CHARLES L. EDWARDS. 


THE ENTEROPNEUSTA 

Recent Literature on the Enteropneusta. 1. Systematic.— 
Spengel has lately given the classification of the Enteropneusta 
a thorough overhauling.* This accepted imperator in the knowl- 
edge of the group recognized at the time 31 species, 9 genera 
and 3 families. Since then 14 species and one genus have been 
added. Nearly all the new ones have come from the Pacific 
and Inđian Oceans, these two enormous reservoirs of unknown 
organisms, the exploration of which has but recently begun in 
earnest. R. C. Punnett’s report, The Enteropneusta in the 
“Fauna and Geography of the Maldive and Laccadive Archi- 


t Die Benennung der PE Zoolog. Jahrb., 15 Bd., 
pp- 209-218, 1901. 


No. 501] NOTES AND LITERATURE 623 


pelagoes,’’ Vol. II, Part 2, pp. 631-680, 1903, stands first in 
point of numbers of new forms, 5 species and 1 genus being 
added in this, all but one coming from the island groups men- 
tioned in the title. The exception, the type of the new genus 
Willeyia, comes from Zanzibar. Besides the 5 full-fledged new 
species recognized by Punnett, the 6 varieties of an old species 
Ptychodera flava are interesting. These are based on a statis- 
tical study of the 222 specimens in the collections. This is the 
first effort made to treat any of the Enteropneusta os 
and is noteworthy on that account if for no other. e author’s 
attitude toward the subject seems practical and sane. He re- 
marks: ‘‘I am not here concerned with the question of the statis- 
tical method as a criterion of species and varieties. My point 
is that in the group of animals collectively designated Pt. flava 
there are to be found different positions of organic stability, 
and in giving to these ‘a local habitation and a name’ there is no 
thought of distinguishing by statistical methods between the 
terms race, variety and species.” The only question would be 
as to the sufficiency in number of specimens examined and the 
structural features considered to justify all these subdivisions 
in this particular animal, and the question is to be answered 
only by further examination of more material. 

The next largest numerical contribution is from the Siboga 
Expedition (Studien über die Enteropneusten der Siboga-expe- 
dition, Monographie XXVI, pp. 1-126, 1907, by J. W. Spengel). 
Three fully accredited species are here described. Worthy of 
note, perhaps of approval, is Spengel’s practise, which is spe- 
cially illustrated in this report, when dealing with certain forms 
which he finds to differ somewhat from any already recorded 
species, but yet not sufficiently to warrant giving them full 
specific rank on the basis of the small evidence at hand. To 
these he attaches a ‘‘provisional’’ specific name. Three such 
names are used in this report. They usually designate speci- 
mens from a particular geographic locality. 

Spengel appears to be ever dubious about the specifie identity 
of specimens of Enteropneusta occurring in widely separated 
places. Thus in his ‘‘Neue Beiträge zur Kenntniss der Enter- 
opneusten,’’ I and II (Zoolog. Jahrb., 1903 and 1904), he ex- 
amines in great detail specimens of Ptychodera flava Eschsch. 
from Laysan, and concludes that they differ sufficiently from 
those deseribed by Willey from New Caledonia, to deserve being 


624 THE AMERICAN NATURALIST [Vou. XLII 


treated provisionally, as distinct. Similarly he examines (Bei- 
trag II) specimens from Funafuti and concludes that these are 
also recognizably different from those from the type locality. 
We consequently have as ‘‘provisional’’ designations Ptychodera 
fl. caledoniensis, Pt. fl. laysanica, and Pt. fl. funafutica. The 
author points out that while Funafuti (8° 30’ S.) lies between 
New Caledonia (20° S.) and Laysan (26° N.), Pt. fl. funafutica 
is not intermediate in structure between the other two forms. 

One might, perhaps, question the utility of speaking of such 
designations as provisional when as a matter of fact no zoolog- 
ical name whatever can be confidently claimed to be final. In 
the reviewer’s opinion there is, nevertheless, real merit in 
Spengel’s practise. It seems to him that proof of the tendency 
of plant and animal kinds to break up into more kinds as soon 
as ready means of intercommunication is prevented, is so strong 
that the systematist is generally bound to suspect that specimens 
from widely separated localities (at least in many groups) are 
different until they are shown not to be so. This provisional 
naming might be looked upon as a recognition of this principle. 

Another Pacific species is from Japan (On a new Enterop- 
neust from Misaki, Balanoglossus misakiensis, n. sp.)? and an- 
other Indian Ocean one from the coast of India (Enteropneusta 
from Madras) .* 

Hardly less notable than the new species from the least ex- 
plored parts of the sea is the bringing to light of new ones in 
the best explored parts. Spengel* describes a species of Glosso- 

-balanus from the Bay of Naples. The author well remarks that 
it is ‘‘sicher aufallend’’ that a new species represented by a 
single specimen should stand accredited to shallow water in the 
immediate vicinity of the Naples Zoological Station. 

2. Development.—What must be counted as the most impor- 
tant contribution to Enteropneust development that has ap- 
peared since Bateson’s series of papers, 1884-1886, has just been 
published by Dr. B. M. Davis (The Early Life-history of Doli- 
choglossus pusillus Ritter.» Davis had shown four years earlier 
that this California species develops without passing through a 
tornaria stage. Dolichoglossus (Balanoglossus) Kowalevskii of 
the Atlantic Coast of the United States, the species studied by 

2 Annot. Zool. japon., Vol. 4, 1902, pp. 77-84. 

5 Quart. Journ. Micro. Sci., Vol. 47, 1903, pp. 123-131. 
t Neue Beiträge III, Zoolog. Jahrb., 20 Bd., 1904, pp. 315-362. 
= Univ. of California Publications in ENN Vol. 4, 1908, pp. 187-228. 


No. 501] NOTES AND LITERATURE 625 


Bateson, develops directly also, it is hardly necessary to mention. 
Since the two species are much alike in most other respects as 
well, the desirability of examining the development of the Pacific 
species was obvious. The report before us is confessedly incom- 
plete so far as the entire developmental history is concerned. 
In some of the phases treated it is, however, measurably full and 
apparently conclusive. The point of most importance perhaps 
as developmental problems are now estimated, pertains to the 
origin of the body cavities. Bateson seemed to find these to 
arise as five diverticula from the archenteron, viz., one anterior 
which produces the cavity of the pre-oral lobe, or in the final 
state the proboscis, a pair immediately behind this producing 
the cavities of the collar region of the adult, and behind these 
another pair which produces the cavities of the rest of the 
animal, i. e.; of the thoracic and abdominal portions. 

Davis finds a radically different course of things. In the 
embryo studied by him a single anterior pouch arises as in D. 
Kowalevskii, but instead of the two pairs coming directly from 
the archenteron, the one anterior pouch sends back lateral 
pockets between the ectoderm and endoderm, and from these 
there is constricted off first a pair of cavities which correspond 
to the future collar, and then in turn from the posterior end of 
this collar pair, a second pair, presumably representing the 
future cavities of the thoracic-abdominal region of the adult, is 
cut off. Since Davis’s results rest upon the examination of a 
large number of embryos (about one hundred and fifty series 
of sections, he tells us), preserved in a variety of ways and cut 
in various directions, it seems they must be accepted, and so the 
conclusion reached that either Bateson’s interpretation of his 
sections was seriously erroneous, or that these two species so 
closely alike in most respects are unlike in this supposedly fun- 
damental point. Davis strongly inclines to the first view and 
presents cogent reasons for his inclination based on a critical 
study of Bateson’s text and figures. 

The bearing of this finding on the problem of the relationship 
between Balanoglossus and Amphioxus is clear. The supposed 
similarity of origin of the body cavities has been taken as a 
leading proof of genetic kinship between the two animals. Davis 
does not fail to point out that his observations justify the doubts 
of the correctness of Bateson’s conclusions entertained by both 
Spengel and Morgan and drawn from their studies of tornaria. 


626 THE AMERICAN NATURALIST (Vo XLII 


While Davis’s work greatly weakens one of the strong supports 
of blood relationship between these two groups, it does not leave 
this weakening wholly uncompensated. It seems to find a 
number of striking resemblances between the egg cleavage of 
this particular enteropneust and that of Amphioxus. But this 
part of the study is less full and the significance of resemblance 
in these earlier developmental stages is more problematic. For 
the character of the correspondences here the reader must be 
referred to the paper itself. 

3. Ecology and Physiology.—Ritter and Davis*® have studied 
quite fully the movements of a tornaria of the California coast 
from near the beginning to the end of its pelagic career. <A 
number of interesting facts pertaining to the character of the 
swimming movements, the correlation of these with its specific 
gravity, and this again with its structure are brought out. 

Davis (paper on the development of Dolichoglossus pusillus 
already referred to) discusses some points on the distribution 
and migration of this species as dependent upon the movements 
of the animal during its larval period, and upon tidal action. 
Davis finds that the breeding time of D. pusillus in San Diego 
and Mission Bays is January and February, and that the fertil- 
ized eggs can be obtained from the burrows of the animals at 
low tide without great difficulty. Particularly noteworthy is 
the fact that in spite of the absence of a true tornaria, the young 
animal still does considerable swimming, and that this follows 
rather closely the general scheme previously found by Ritter 
and Davis to characterize the swimming of the tornaria of 
another species above alluded to. 

Ritter’ has studied the movements of the adult Dolichoglossus 
pusillus and a California species of Balanoglossus with the spe- 
cial view of gaining a better understanding of the action of the 
proboscis and skeletal musculatures and the relation of these to 
the skeleton. The results make it probable that the nuchal skel- 
eton together with the so-called notochord serves not merely as a 
support for the isthmus, or neck, but also as an axis upon which 
the muscles of locomotion act, in part at least. 

4. Anatomy.—The classification of the Enteropneusta is based 

° Studies on the Ecology, Morphology, and Speciology of the Young of 
Some Enteropneusta of Western North America. Univ. of Calif. Publica- 
Hoe Zoology, Vol. 1, 1904, pp. 171-210. 

"The Movements of the Enteropneusta and the Mechanism by which 


a oe Biolog. Bull., Vol. III, pp. 255-261. 


No. 501] NOTES AND LITERATURE 627 


on a thoroughgoing examination of everything in the make-up 
of the animals, thanks particularly to the standard set by 
Spengel’s splendid monograph of 1893. From this circum- 
stance it follows that anatomical studies on the adults of either 
old or new species are not likely to yield greatly important new 
facts. A few points of considerable general interest, however, 
come from recent work. 

The superficial, presumably secondary, metamerism of por- 
tions of the body in several species has attracted the attention 
of most observers. Willey and Spengel have given it special 
consideration. In no known species is this more strikingly seen, 
perhaps, than in the Neapolitan one lately described by Spengel. 
The prominence and regularity of the bilaterally arranged cross- 
welts or ridges on the ventral side of the genital region as 
figured by him, are remarkable indeed. It is not likely that 
these structures have any great significance either phylogenetic 
or physiological. They are probably in the main growth char- 
acters and are interesting on just this account. 

In his extensive studies on the exeretory organs of annelids 
and amphioxus some years ago, E. S. Goodrich predicted that a 
peculiar type of cells observed in these animals and called by 
him Solenocytes, would on special search be found in the Enter- 
opneusta. Spengel has given attention to this point, with nega- 
tive results so far. (Beitrag III.) 

References may here be made to Spengel’s tilts with Arthur 
Willey on the latter’s speculations as to the vertebrate homol- 
ogies of various Enteropneust organs. For example, Spengel 
examines with his accustomed thoroughness the dorsal nerve 
roots of the collar region in several species and treats with quite 
pungent sarcasm Willey’s contention that in these we have the 
homologues of the vertebrate epiphysis. A fragment of this 
particular tilt is worth repeating as literature, though it may be 
questioned whether Willey ever took himself seriously enough in 
much of his theorizing on these matters to warrant giving his 
utterances much time under the aegis of real science. ‘‘An 
epiphyseal structure,” Willey is quoted as saying, ‘‘like an 
enteropneustic root, can be transformed into an epiphyseal 
structure like a pineal eye by losing its primary function . . . 
passing through a condition of pigmentose degeneration . 
and then being rejuvenated by the acquisition of a new fune- 
tion.” Then Spengel himself, ‘‘wo in aller Welt giebt es eine 


628 THE AMERICAN NATURALIST (Von XLII 


Stütze fiir eine solche Annahme, dass ein pigmentoser Degenera- 
tion anheimgefallenes Organ einer Verjiingung durch Erwerb- 
ung einer neuen Funktion fähig ware ... ???—und dann 
schliesst gar der Satz, the agens of rejuvenescence being some 
orm of natural selection! . . . heisst das etwa nicht, den Spot- 
tern über die Selektionstheorie Wasser auf die Mühle tragen?! 
Es wird Einem ja schwindlig, wenn man an diesen babylonischen 
Turnbau nur denkt!’’ W. E. RITTER. 


VERTEBRATE PALEONTOLOGY 

Pelycosauria of North America..—There are few groups of 
animals at the present day of greater interest to the paleon- 
tologist and evolutionist than the extinct air-breathers of the 
Permian; and, of the Permian vertebrates, those of America, in 
their abundance, variety and excellence of preservation are easily 
the chief. As is well known, Professor Case has, for the past 
ten years or more, given much intelligent attention to the Per- 
mian reptiles of America, and especially to the group which he 
has described in the present handsome memoir as the ‘‘suborder”’ 
Pelycosauria. And the writer is inclined to think that he is a 
little too conservative here, for he believes that the structural 
characters are so diverse, so widely divergent from those of the 
modern Sphenodon, that to include them both in one and the 
same order is to hinder rather than advance an intelligent 
taxonomy of the reptiles. Mr. Case has given in the volume a 
complete history of the literature of the group, a taxonomic 
revision, a thorough discussion of the structural characters of 
the pelycosaurs, and the facts of their range and distribution. 

e has not, rather wisely, entered very fully into the many 
philosophical matters that the animals suggest. He expresses 
the opinion, however, that the pelyeosaurs represent a highly 
specialized and short-lived branch of the rhynchocephalian stem, 
and in that he will probably have the concurrence of most 
paleontologists. But, to the writer, this does not seem altogether 
certain. The group has am abundance of generalized char- 
acters in the vertebre, pectoral and pelvic girdles, cleithra, ete., 
the specialization consisting, for the most part, in the extra- 
ordinary and most bizarre elongation of the vertebral spines, the 
teeth, ete. His reasons for the grouping he makes are chiefly to 
be found in the temporal region of the skull; and the writer 

*Case, E. C. Revision of the Pelycosauria of North America. Memoir 
of the Carnegie Institution of Washington, pp. 1-176, pls. I-XXXV, 1907. 


No. 501] NOTES AND LITERATURE 629 


does not think he is expressing too heretical an opinion when 
he doubts the great importance of this region in the primary 
classification of the reptiles. The grouping of the reptiles into 
two subclasses, the Diapsida and Synapsida, based chiefly upon 
the temporal structure, is rejected by most students of the 
reptiles, and the very aberrant structure of this region in the 
pelyeosaurs, especially the presence of a ‘‘prosquamosal’’ bone, 
rather shakes one’s faith. However, we are not quarrelling 
with the author for not going into these doubtful discussions. 
He has, what is better, given us excellent material for future 
philosophizing in his full and lucid descriptions and many 
illustrations. S. W. WILLISTON. 


The Conrad Fissure.!—Mr. Brown has given us in this paper an 
excellent critical and descriptive list, well illustrated, of a very 
important pleistocene bone deposit, especially interesting as 
located in the southwest. The material, for the most part col- 
lected, and it need not be said skillfully collected by the author, 
is abundant, including seven species of insectivores, two of bats, 
nineteen of carnivores, as many of rodents, and nine of ungu- 
lates, together with several of amphibians and reptiles. Of these 
‘the deseribes a new twenty species and two genera, the more 
noteworthy of the new genera being one of a new type of saber- 
toothed cats. Conspicuous for their absence are remains of the 
large edentates and of the proboscideans, from which the author 
is inclined to the belief that the former, at least, were not then in 
existence in North America. That some of the sloths were in 
existence in South America at that period is more than probable, 
if we take into account Gryphotherium, and the same logic would 
exclude the proboscideans from the fauna, which is not at all 
probable. He also concludes that the fauna was boreal, as indeed 
would be indicated by the remains of musk oxen. The paper is 
a valuable addition to our faunal pan literature. 

. WILLISTON. 


The Ankylosauridae." —Mr. Brown has given us a rather 
startling restoration of what he believed to be a new family of 
! Brown, Barnum. The Conrad Fissure, A Pleistocene Bone Deposit in 
Northern Arkansas, with Descriptions of Two New Genera, and Twenty 
New Species of Mammals. Mem. Amer. Mus. Nat. Hist., IX, pp. 157-208, 
pls. XXIV, XXV, 1908. 
*Brown, Barnum. The Ankylosauride, A New Family of Dinosaurs 
from the Upper Cretaceous. Bulletin of the American Museum Nat. Hist. 
X, XXIV, pp. 187-201, 1908. 4 


630 THE AMERICAN NATURALIST (Vou. XLII 


armored dinosaurs. from the Hell Creek Beds of Montana. The 
material, however, upon which he bases his restoration was 
scanty—too scanty to serve as a satisfactory basis for a restora- 
tion—consisting of the skull, a number of vertebre, a somewhat 
problematical scapula, and a number of dermal scutes. The 
dangers of such attempted restorations as the present one ou 
such imperfect material are apparent here, since Ankylosaurus 
is either very closely allied to or identical with Stegopelta 
Williston, a genus overlooked by Mr. Brown. And Stegopelta, 
which is represented by considerable material in the University 
of Chicago collections, is as closely allied as well may be with 
Polacanthus Hulke of England, and must go in the same family. 
A comparison of: Nopsea’s restoration of Polacanthus, which is 
essentially correct, save for the skull, will show the real form 
of Ankylosaurus, very different from that given by Mr. Brown. 
Stegopelta, moreover, has spines, and the body is covered in 
large part by small scutes, though there are also large ones, as 
figured by Mr. Brown; and the tail rings are correctly placed 
by Brown. The writer has examined the specimen in the British 
Museum, and is assured of the relationships. Stegopelta will 
shortly be more ar! described and figured by Dr. Moodie. 
S. W. WILLISTON. 


PARASITOLOGY 

The Evolution of Parasitism.—In a recent paper entitled: ‘‘The 
Influence of Symbiosis upon the Pathogenicity of Microorgan- 
isms (The Evolution of Parasitism),’’ Musgrave! has brought 
together some most important items in an extremely suggestive 
manner. He defines symbiosis as representing all phases of asso- 
ciation between living organisms, beginning with commensalism, 
on the one hand, and including true parasitism, on the other, in 
which either component is influenced in nutrition, metabolism, 
production or in some other manner by the presence of the other. 
While this use of the term is distinctly new and rather at vari- 
ance with the older usage of van Beneden the meaning of the 
author is clear. He endeavors to show that symbiotic combina- 
tions between microorganisms are responsible for uninterpreted 
phenomena in the etiology and pathology of disease. Further- 
more, he adduces evidence to show that changes is symbiosis may 
produce changes in metabolism and also, as a result of this, 

1 Philippine Jour. Se., B 3: 78. 


No. 501] NOTES AND LITERATURE 631 


changes in the pathogenic character of parasites and in the 
susceptibility of hosts. The work of other authors is cited indi- 
cating the influence that surroundings have on cultures of 
bacteria even under experimental conditions and leading to the 
conclusion that the relation between nutrition, metabolism and 
production is far more significant than has heretofore been con- 
sidered in laboratory technique. If such influences modify 
artificial cultures, there will surely be a much greater effect from 
the complex conditions surrounding mixed cultures in unknown 
symbiosis. 

Among animal parasites nutrition, metabolism and production 
certainly are more complicated than with bacteria, and unless 
this fact is constantly in mind the whole subject of parasitism is 
apt to be considered along too narrow lines and our specificities 
to be regarded as too exacting. The question, just as with 
bacteria, not only involves a study of the interaction between 
an animal host and animal parasites, but a study of host under 
constantly varying conditions being acted upon by parasites in- 
fluenced by an ever-changing environment. A battle, as it were, 
takes place between two sets of very complex influences, leading 
to death or disease of the host on the one hand, to destruction 
or commensalism on the part of the parasite on the other, or 
finally quite frequently to what Theobald Smith has called a 
condition of balanced parasitism. 

Most suggestive in this direction is the experimental work 
which has been done with ameba. Chief among the investigators 
are Musgrave and Clegg, who found that the cultivation of 
amceba could not be accomplished satisfactorily except in the 
presence of other living organisms, and this symbiosis is more 
or less specific although its specific character may be changed 
both experimentally and probably also under natural conditions. 

e author sums up his paper as follows: 

“I am convinced that such an evolution of parasitism from an 
ameebie and bacterial symbiosis, in water or elsewhere in nature, through 

a beginning or mixed tissue and bacterial parasitism in amæbic ulcers 
of the colon, to a true tissue parasitism in the internal organs of the 
body, or even to a blood invasion itself, is a matter of frequent oceur- 
rence. The most promising field for laboratory research in the future 
will be the study of cause and effect, in the complex relations in which 
they occur in nature, of the interrelation and interaction of miero- 
organisms with each other and in their environment of complex 
symbiosis and the ever-changing and multiple conditions found in hosts.” 


632 THE AMERICAN NATURALIST [Vou. XLII 


Trypanosomes.—The life history of various trypanosomes has 
been investigated with great care at the Runcorn Research Labo- 
ratory, Liverpool, by J. E. S. Moore and A. Breinl, with several 
collaborators. The results appear to be uniform and to differ 
markedly from those of previous work. These authors are un- 
able to make any distinction between the so-called male, female 
and parthenogenetic forms of Schaudinn and hold that mere 
varieties in size or even in some morphological features when 
taken from different parts of the life cycle should not be spoken 
of under terms which imply conjugation when no such phe- 
nomenon takes place so farasisknown. Trypanosoma gambiense 
and T. lewisi manifest a cyclical metamorphosis corresponding 
closely to alternate presence and absence of the parasites from 
the blood. Periods of maxima and minima alternate irregularly 
and not with the definite chronicity seen in the development of 
the malarial organisms. The coming of a minimum is accom- 
panied by the formation of latent bodies consisting of nucleus 
and vesicle enclosed by a delicate covering of cytoplasm. These 
latent bodies lodge chiefly in the spleen and bone marrow and 
from them are developed later a new generation of the typical 
flagellate forms. Associated with the formation of the latent 
bodies is an interaction, which occurs at or near the maxima, 
between the extra-nuclear centrosome, perhaps better named 
the blepharoplast and the nucleus. It is inferred that the real 
sexual phase occurs within the transmitting insect, although 
other investigators look upon the rôle of the latter as purely 
mechanical. 

In T. equiperdum, which is the cause of dourine, the entire 
life history is confined to a single animal and not complicated by 
transfer through an intermediate host. When inoculated in a 
rat the process appears identical with that outlined above, save 
that the round forms which occur at the period characteristic 
of latent bodies possess two long and delicate flagella. There is 
in the rat but a single maximum which is followed by the death 
of the host; in horses the parasites are not sufficiently numerous 
to permit the observer to follow the changes which take place. 

HBW 


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CONTENTS OF THE MARCH NUMB 
t Harvard University. Professor 


Ho 
os Evolutien of the Ter Tertiary Mammals and the Impor- 
w Dario. Their Nae Professor CHARLES 


What. pig erar Professo 

Bhorter Articles and Aiseee d The Inheritance 

of ee er of Clasping the Hands, Dr. FRANK 
Notes and Literature: Jchthology—Ichthyol mio 

President DAVID STARR JORDAN. Echin era re 

ed Crinoids of the Sibo ierpedition, 

AusTIN HOBART CLARK. re gr athology— ie 


ENR WAR 
Animal y tirni iaa va — Work on the Behavior of of 
Higher Animals, P. rT HERBERT 8, JEN 


CONTENTS OF THE APRIL NUMBER 

The Taxonomic Aspect of = Species Question. Pro- 
fessor CHARLES E. BESS 

The Taxonomic Aspect of T the Species Question. Dr, 
NATHANIEL LORD BRI 

The lacing ea aa footed of ti the Species Question. Pro- 
fessor J. 

The „Physiólogical pye of a Species. Dr. D. T. 

UGAL. 

ån Tooele View of the Species Conception, Professor 
FREDERIC E. CLEMENTS. 

An eye fae ups of the Conception of Species, Dr, 


eae ore of ‘the — S Question. Professor J. M. 
COUL PoLLock, Professor T. J. 
ra HILL Dr. G. E. SHULL, Dr. J. A, 


—Przibe 
m’s Experimental gy. aii eekly 
rdan o R 


— and Literature ay, essay 
oolo 
Jo n Fishes. Professor FREDERIC T, L 


ee ek OF THE MAY ETEA 


me sge e, Origin the Bermuds 
apod F auna., Professor A, E. aa 
On the aega ota aea = ease Tropisms of Insects, 


CHARLES TH 


es ” 

The ological Laborato the Bureau of Fisheries at 
Wood’s Hole, Mass.: papi noid Work for the Season 
ef 1907. Dr, Francis 


3 


Renewed In- 
terest in Recent Crino oids, H, L. i —— Be- 
Aavior—Recent Work on the Bebarise of the Higher 
Animals. Professor HERBEBT 5, JENNINGS, 


CONTENTS OF THE JUNE NUMBER 
The Ancestry of the Caudate Amphibia, Dr. Ror L 
Moone. 


and their spg nmd to other Organe 
Professor HENRY AR 
The Faunal Affinities of the Prairie Begiei of Central 
rth America Dr. ALEXAND gon RUTHVES. 
Physiology. Professor ARPER S.L 


Notesand Literature: Biome cust Contributions 
ry, Professor place PEARL., Protozoa— 
Some Ameba Studies, G. N. 


OF THE JULY NUMBER 


A New Mendelian Ratio and Se f Laten 
Dr. GEORGE HARRISON SHULL. oo na 
Saag. Dais of Insects. Professor C, W. Woop- 


Abnormal Incisors of Marmota Monax L. CHARLES 
AN nh = ooo Coloration of Plethodon Cinereus. HUGE 


n Pea on: the Order of Success f 
Somites in the Chick. Professor Manan Ek How 
Dwarf Faunas, 


Professor Hervey W, SHIMMER, 
Notes and oven _dehityelogy—Life History of the 
LES A, KOFOID; ere ee 
à 


CONTENTS OF THE AUGUST NUMBER 
The Mid-summer Bird Life of Miinois : A Statisti cal 
gri Professor S. A. FORBES. 
Life C e, of raees hee subjected. to a 
ronment. R. LORANDE Woop- 
RUFF. 


Placobdella Pediculata n. sp. ERNEST E. HEMINWAY. 
Marine Laboratories and our Atlantic Coast. DR. AL- 


big oo as a Method in cn peo Professor 
CHARLES LINCOLN EDWARDS, 


su he wer Miocene of 
Coo 


Notes a end Literature: Plant Cytology—Some Recent Re- 
estat = the Cilia-forming Organ of Plant oo Dr. 
yY M. Davis. Ornithology—Riddle on the 
Se ot grit and the Cause = Alternation 
rs, 


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CONTENTS 


The Manifestations of the Principles of Chemical Mechanics in the oe 
Plant. DR. F. F. BLACKMAN 

The Desiccation of Rotifers. D. D. WHITHEY i 

On the Habits and the Pose of the TAR Dinasaurs, expecially of 
Diplodocus. DR. OLIVER P. HAY . 

Shorter Articles and Correspondence: Juvenile Substitutes i smoking 
Tobacco. Professor WILLIAM ALBERT SETCH 

Notes and Literature: Heredity—Recent Sila in Haman ‘Heredity, Dr. 
F. A. Woops. Ornithology- Riddle on the Cause of the Production of 
Down and Down-l of Birds, J.A.A. Vertebrate 
Paleontology—New Fossil Mammals from Egypt, T DAC. 


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THE 
AMERICAN NATURALIST 


Vout. XLII October, 1908 No. 502 


THE MANIFESTATIONS OF THE PRINCIPLES OF 
CHEMICAL MECHANICS IN THE LIVING 
PLANT. 


F. F. BLACKMAN, M.A., D.Sc., F.R.S. 


THE UNIFORMITY OF NATURE. 

Among the phenomena of nature man finds himself to 
be one of medium magnitude, for while his dimensions 
are about a billion times as great as those of the smallest 
atoms that compose him they are also about one billionth 
part of his distance from the center of his solar system. 

From the vantage point of this medium magnitude the 
man of science scans eagerly the whole range of natural 
phenomena accessible to him with a strenuous desire for 
unity and simplification. 

By the unwearying study of special sections of this 
long front of natural phenomena special guiding princi- 
ples have been detected at work locally. No sooner has 
this been accomplished than, in obedience to this desire 
for continuity throughout, such principles have been free- 
ly extended on either side from the point of discovery. 

Thus, the theory of probability, which dealt at first 
with so limited an occupation as drawing white and black 
balls out of an opaque bag, now is known as the only de- 
terminable factor in such remote things as the distribu- 
tion of the duration of human lives and the effect of con- 
centration of the colliding molecules in a solution upon 
the rate of their chemical change. Again, the principle 
of evolution discovered among living things has been 


* Address of the president of the Botanical Section of the British Asso- 
ciation for the Advancement of Science. Dublin, 1908. 


633 


634 THE AMERICAN NATURALIST [ Vou. XLII 


extended, till to speak of the evolution of societies, of 
solar systems, or of chemical elements is now but com- 
monplace. 

The biologist, with all his special difficulties, has at 
least the limitation that he is only concerned with the 
middle range of the interminable hostile front of natural 
phenomena, and that for him is ordained the stubborn 
direct attack, leaving the brilliant attempts at outflanking 
movements to the astronomers on the one wing and the 
workers at corpuscular emanations on the other. 

The atoms and molecules that the biologist has to deal 
with do not differ from those passing by the same names 
in the laboratories of chemistry and physics (at least no 
one suggests this), and their study may therefore be left 
to others. At the other end of the seale, with astronom- 
ical magnitudes we have not to deal, unless indeed we 
yield to the popular clamour to take over the canals on 
Mars as phenomena necessarily of biological causation. 

In the study of that particular range of phenomena 
which is the special allotment of the physiologists, animal 
and vegetable, we have had ever before us the problem 
of whether there is not here some discontinuity in nature; 
whether the play of molecular and atomic forces occur- 
ring outside the living organism can ever account for the 
whole of the complexity and correlation of chemical and 
physical interactions demonstrable within the living struc- 
ture. 

As yet we are of course far from any answer to this 
question, and no one in a scientific assembly like this will 
call upon us for prophecies. Yet the subject to which 
I shall devote my address has a bearing upon this ques- 
tion. I propose to consider a particular aspect of the 
relation of chemical changes in a test-tube to those taking 
place in a living growing plant, and this in the spirit of 
one who craves for continuity throughout natural phe- 
nomena. 

The point of view from which the chemist regards the 
reaction taking place in his test-tube has undergone a 


No. 502] CHEMICAL MECHANICS IN LIVING PLANT 635 


change in the last twenty years, a change bringing it more 
into uniformity with that of the biologist. No longer 
content with an equation as a final and full expression of 
a given reaction, the chemist now studies with minutest 
detail and with quantitative accuracy the progressive 
stages of development of the reaction? and the effect upon 
it of varied external conditions, of light, temperature, 
dilution, and the presence of traces of foreign substances. 
Perhaps it is too much to believe that this, as it were 
physiological, study of each reaction is the effect of some 
benign irradiation from the biological laboratory. At 
least, however, it is true that it is the modern study of 
‘slow’ chemical reactions which has made all this pos- 
sible, and the living organism consists almost entirely of 
slow reactions. The earliest studied chemical reactions, 
those between substances which interact so quickly that no 
intermediate investigation can be made, did not of course 
lend themselves to this work, but nowadays whole classes 
of reactions are known which are only completed hours 
or days after the substances are initially mixed. To the 
slow reactions belong all the hydrolytic and dehydration 
changes of carbohydrates, fats and proteids that bulk so 
largely in the metabolism of plants and animals, together 
with other fermentation changes such as are brought 
about by oxidases, zymases and enzymes in general. This 
precise quantitative study of chemical reactions has been 
developing with remarkable acceleration for some twenty- 
five years, till it is grown almost into an independent 
branch of science, physical chemistry. This is sometimes 
called ‘‘general chemistry’’ because its subject is really 
the fundamental universal laws of the rate of chemical 
change, and these laws hold through all the families, gen- 
era and species of chemical compounds, just as the same 
physiological laws apply to all the different types of 
plants. : 
* Modern research has made it clear that reactions conventionally repre- 
sented by complex equations of many interacting molecules really take place 


in a succession of simple stages, in each of which, perhaps, only two 
molecules interact. 


636 THE AMERICAN NATURALIST [ Vou. XLII 


Now if these laws are fundamental with all kinds of 
chemical changé they must be at work in the living meta- 
bolic changes. If the chemical changes associated with 
protoplasm have any important factor or condition quite 
different from the state of things which holds when mole- 
cules react in aqueous solution in a test-tube, then it might 
happen that the operation of these principles of physical 
chemistry would be obscured and not very significant, 
though it is inconceivable that they should be really inop- 
erative. 

My present intention, then, is to examine the general 
phenomena of metabolism in an attempt to see whether the 
operations of these quantitative principles are traceable, 
and if so how far they are instrumental in giving a clearer 
insight into vital complexity. 


THe DOMINANCE oF [RRITABILITY IN PHYSIOLOGY. 


I think that certain manifestations of these principles 
are indeed quite clear, though not generally recognized, 
and that this neglect is largely due to the dominance of 
what our German colleagues call ‘‘Reizphysiologie’’—the 
notion that every change in which protoplasm takes part 
is a case of the ‘‘reaction’’ of an ‘‘irritable’’ living sub- 
stance to a ‘‘stimulus.’’ Now this general conception of 
protoplasmic irritability, of stimuli and reactions was, of 
course, a splendid advance, the early development and ex- 
tension of which we owe largely to our veteran physiolo- 
gist Professor Pfeffer, of Leipzig. Great as is the service 
it has rendered to many departments of botany, yet in one 
direction, I think, it has overflowed its legitimate bounds 
and swamped the development of the physical-chemical 
concepts which I shall indicate later on. The great merit 
- of the ‘‘stimulus and reaction’’ conception is that it sup- 
plies a very elastic general formula for the sort of causal 
connection that we find occurring in all departments of bi- 
ology; a formula which allows the phenomena to be 
grouped, investigated and formally expounded, whether 

they be the temporary turgor-movements of ‘‘sensitive’’ 


No. 502] CHEMICAL MECHANICS IN LIVING PLANT 637 


plants, the permanent growth movements of tropistie cur- 
vatures, or the complex changes of plant-form and de- 
velopment that result from present and past variations of 
external conditions. 

The strength and the weakness of the conception lie in 
its extraordinary lack of particularity. When an irritable 
cell responds to a stimulus by a reaction nothing is im- 
plied about the mechanism connecting the cause and the 
effect, and nothing even about the relative magnitudes 
of these, but all this is left for special research on 
the case under consideration. The one natural chain of 
cause and effect that is recognized to be outside this com- 
prehensive category is that rather uncommon one in which 
a definite amount of energy of one kind is turned into an 
equivalent definite amount of energy of another. Here 
we have a direct ‘‘equation of energy,’’ whereas in a reac- 
tion to a stimulus we are said to have typically an ‘‘un- 
loosing’’ effect—a liberation of potential energy by a 
small incidence of outside energy, as in the classical an- 
alogies, drawn from completely comprehended non-living 
things, of a cartridge exploded by a blow, or the liberation 
into action of a head of water by the turning of a tap. 

So elastic a conception may be easily stretched to fit al- 
most any sequence of phenomena with the apparent close- 
ness that argues a bespoken garment. We must therefore 
be critically on our guard against cases of such sartorial 
illusion. 


THE PRINCIPLES oF CHEMICAL MECHANICS. 


That my consideration of particular cases may be intel- 
ligible it seems necessary that I devote a few minutes 
to outlining the four quantitative mechanical principles 
which govern every single chemical reaction, though much 
that I have to say has been drawn from elementary books 
on physical chemistry. 

These four principles are concerned with (1) the nature 
of the reaction in question; (2) the amount of reacting 
substances that happen to be present; (3) the temperature 


638 THE AMERICAN NATURALIST [ Vou. XLII 


at which the reaction is taking place; and (4) the influence 
of catalysts upon the reaction. è 

For the moment we will confine ourselves to the first 
two matters, and assume that catalysts are absent and the 
substances at constant temperature. 

1. The first principle that we have to consider is that 
which declares that no chemical reaction is really instan- 
taneous, though the interaction of substances is often so 
fast that a direct measurement of its rate can not be 
made; and, further, that every reaction has its own spe- 
cific reaction-velocity which distinguishes it from other 
reactions. This is expressed by giving to each particular 
reaction a numerical velocity coefficient which is low or 
high proportionally as the reaction is slow or quick. 

2. This coefficient only expresses the actual experimen- 
tal velocity when the reacting substances are present in 
unit concentration, because difference of concentration is 
just the most important factor controlling the actual re- 
action-velocity. 

If a solution of a substance A of unit concentration is 
undergoing change, then to keep this reaction going at its 
present rate fresh amounts of A must be added continu- 
ally just to equal the amount removed by the reaction and 
so keep the substance up to unit concentration. The 
amount of A that had to be added thus per unit time would 
give an exact measure of the amount being decomposed, 
í. e., of the specific velocity of this reaction. 

If the reaction were started with A at double unit con- 
centration, then twice as much A would have to be added 
per unit time to keep the reaction velocity constant at the 
double rate it would have started at. 

And with higher concentrations proportionally more A 
would have to be added. It is therefore shown that the 
amount of chemical change going on in unit time is pro- 
portional to the concentration. This is a most funda- 
mental principle of chemical mechanics, known as the law 
-~ of mass, and it may be stated thus: the amount of chem- 

ical e taking place at any time is amaya propor- 


No. 502] CHEMICAL MECHANICS IN LIVING PLANT 639 


tional to the amount of actively reacting substance (or 
substances) present. 

To carry out experiments by the procedure given above 
is in practise very difficult and the velocities of reactions 
are never measured by the chemist in this way. In a 
living organism this continual bringing up of new supplies 
of material to maintain a constant rate of change is the 
ordinary way of life, but in the chemical laboratory pro- 
cedure is different. There, definite amounts of sub- 
stances are initially mixed in a vessel and the reaction is 
allowed to progress by itself without further additions. 
In this ease there is a continual falling off of the concen- 
tration of the substance, and so a corresponding diminu- 
tion of the actual reaction-velocity. 

In this procedure the diminution of the initial amount 
of substance can be actually measured by withdrawing 
small samples at intervals of time and analyzing them. 
Let us consider a definite example. Cane-sugar can be 
hydrolyzed, under various conditions, to give two mole- 
cules of hexose, according to the equation 


C,2H..0,, + H,O = 2C 4H 20.. 


This reaction goes on, though extremely sowly, when an 
aqueous solution of cane-sugar is kept very hot in a beak- 
er. Suppose we started with, say 128 grams dissolved 
in a liter of water and traced the diminution of this 
amount down towards zero by withdrawing samples at 
intervals of time and analyzing them. If we plotted the 
sugar-content of these successive samples against the 
times when they were taken we should get the curve given 
in Fig. 1. If we call n minutes the time taken for the 
sugar to diminish from 128 grams to 64 grams, we 
should find that in the second n minutes the sugar had 
fallen to 32 grams, after 3n minutes to 16 grams, 
and so on, the amount halving itself every n minutes. 
Thus the amounts of cane-sugar hydrolyzed in successive 
equal intervals are 64, 32, 16, 8, 4, 2, 1 grams, amounts 
in each case just exactly proportional to the quantity of 


640 THE AMERICAN NATURALIST [ Von. XLII 


cane-sugar then remaining in solution, thus exemplifying 
the law of mass. 3 

Such a curve as A in Fig. 1, which changes by a con- 
stant multiple for successive units of time (here halving 
itself every n minutes) is known as a logarithmic curve; 
the velocity of reaction at any moment is exactly indi- 
cated by the steepness of the curve at that moment; the 
velocity is greatest at first and it declines to almost zero 
as the curve approaches the horizontal at the end of the 
reaction. 

When instead of the decomposition of a single substance 
we deal with two dissolved substances, A and B, reacting 
together, then as both of them go on being thus used up, 
the amount of change must be ever proportional to the 
mass or amount of A present multiplied by the mass of B 
present. 

There is a special important case when the amount of, 
say, B is in very great excess of that amount required to 
unite with the whole of A. Then all through the slow 
progress of the reaction the amount of B never becomes 
reduced enough to make appreciable difference to its 
mass, and it may be considered as practically constant all 
along. In such a ease the rate of the reaction is found 
to be proportional simply to the amount of A present, and 
we get again the curve A, Fig. 1. Here the amount of 
A may be considered as a limiting factor to the amount of 
reaction; B being in such great excess never falls low 
enough to take a practical part in determining the velocity. 

The case of the hydrolysis of cane-sugar in aqueous 
solution is just such a case. The water itself enters into 
the reaction, but so little is used up in relation to the 
enormous excess present that the amount remains prac- 
tically constant and the rate of hydrolysis of the cane- 
sugar is determined only by the amount of the cane-sugar 
present at any moment.* 

3. We have now shown how the actual amount of chemi- 
cal change going on in a solution is determined by the 


*128 grams ecane-sugar unite with 6.7 grams water in Casein and in 
our oe nearly 1,000 grams of water are present 


No.502] CHEMICAL MECHANICS IN LIVING PLANT 641 


combined effect of (1) the specific reaction velocity and 
(2) the law of mass. We have next to point out that the 
specific reaction coefficient is not the same under all cir- 
cumstances, but is affected by variations of external con- 
ditions, always by temperature, and generally by the pres- 
ence of traces of so-called catalysts. 

The relation to temperature we will postpone, and pro- 
ceed to consider our third principle, the acceleration of re- 
action velocity by catalytic agents. 


| B , | 


Fa) 


do | 

90 

Bo \ 
7° \ 


A \ 
Crk 


$020 z ; 
4a a 
AT 
: ~ig NE d 
Mno m 2h 3H Oh Sn br yn Sm 


Fig. 1. 


It has long been known that small additions of various 
foreign substances may have a great effect in increasing 
the rate at which a reaction is proceeding. Thus this hy- 
drolysis of cane-sugar, so slow with pure water, goes ata 


642 THE AMERICAN NATURALIST [Vou. XLII 


fair velocity if a few drops of a mineral acid are added to 
the solution, while the addition of a trace of a particular 
enzyme (invertase from plant or animal) enormously in- 
creases the rate of change, so that the whole 128 grams 
of cane-sugar are soon hydrolyzed to hexose. The reac- 
tion progresses quantitatively in the same sort of way as 
before, giving a logarithmic curve of sugar-content. In- 
deed the same graphic curve, Fig. 1, A, would represent 
the facts if the value of n were reduced from many hun- 
dred minutes to quite a few. 

The most striking point about this new state of things 
is that the added body is not used by its action, but the 
acid or enzyme is still present in undiminished amount 
when the reaction is completed. 

Such actions were at first styled ‘‘contact’’ actions, but 
are now known as catalytic actions, because we have 
learned that the catalyst does not work just by contact but 
by combining with the sugar to form an intermediate ad- 
dition compound, and that this compound is then split up 
by the water liberating the catalyst again, but freeing the 
sugar part, not as cane-sugar, but combined with the water 
to form two molecules of hexose. 

On many chemical reactions, finely divided metals such 
as platinum and gold have a very powerful catalytic ac- 
tion. Thus platinum will cause gaseous hydrogen and 
oxygen to unite at ordinary temperatures, and will split 
up hydrogen dioxide with the formation of oxygen. The 
intermediate stages in this catalytic decomposition may be 
summarily simplified to this— 

H,O, + Pt = PtO + H,O 
and 
PtO + HO, = Pt + 0, + H,0. 


Thus the reaction goes on and on by the aid of the ap- 
pearing and disappearing ‘‘intermediate compound’’ PtO 
till at the end the H,O, is all decomposed and the platinum 
is still present unaffected. 

The enzymes are the most powerful catalytic agents 


No. 502] CHEMICAL MECHANICS IN LIVING PLANT 643 


known, and most of them are specifically constituted to 
effect the hydrolysis, oxidation, reduction or splitting of 
some definite organic compound or group of compounds 
containing similar radicals. 

Innumerable enzymes have in late years been isolated 
from the plant-body, so that it would seem that there is 
none present-to catalytically accelerate each of the slow 
single changes that in the aggregate make up the complex 
metabolism of the plant. 

The law of mass applies with equal cogency to catalytic 
reactions. If twice the amount of acid is added to a so- 
lution of cane-sugar (or twice the amount of enzyme) 
then the reaction velocity is doubled, and hydrolysis pro- 
ceeds twice as fast. As the catalyst is not destroyed by 
its action, but is continually being set free again, the con- 
centration of the catalyst remains the same throughout the 
reaction ; while, on the contrary, the amount of cane sugar 
continually decreases. 

If the catalyst be present in great excess the amount 
of hydrolysis will be limited by the amount of cane-sugar 
present, and as this is used up so the reaction will prog- 
ress by a logarithmic curve as in Fig. 1, A. In this case 
B may represent the amount of catalyst. If, on the con- 
trary, there is a large amount of sugar and very little 
acid or enzyme present, so that the catalyst becomes the 
limiting factor, then we happen upon a novel state of 
things; for by the law of mass the rate of hydrolysis 
will now remain constant for some time till the excess of 
sugar is so far reduced that it in turn becomes a limiting 
factor to the rate of change. In this case the velocity 
curve would consist of a first phase with a straight hor- 
izontal line of uniform reaction-velocity leading into the 
second phase of a typical falling logarithmic curve (see 
Fig. 1, C). These conditions have been experimentally 
examined by Horace Brown and Glendinning, and fully 
explained and expounded by E. F. Armstrong in Part IT 
of the critical ‘‘Studies in Enzyme Action.’’ 

* Proc. Roy. Soc., Vol. LXXIII, 1904, p. 511. 


644 THE AMERICAN NATURALIST [ Vou. XLIT 


Having now outlined the three fundamental principles 
of reaction-velocity, the law of mass, and the catalytic 
acceleration of reaction-velocity, we are in a position to 
consider the broad phenomena of metabolism or chemical 
change in the living organism from the point of view of 
these principles of chemical mechanics. 


Tue METABOLISM OF THE PLANT CONSIDERED AS A CATALYTIC 
REACTION. 


Plants of all grades of morphological complexity, from 
bacteria to dicotyledons, have this in common, that 
throughout their active life they are continually grow- 
ing. Putting aside the qualitative distribution of growth 
that determines the morphological form, as a stratum of 
phenomena above the fundamental one that we are about 
to discuss, we find that this growth consists in the assim- 
ilation of dead food-constituents by the protoplasm with 
a resulting increase in the living protoplasm accompanied 
with the continual new formation of dead constituents, 
gaseous CO., liquid water, solid cellulose, and what not. 
This continual flux of anabolism and katabolism is the 
essential character of metabolism, but withal the proto- 
plasm increases in amount by the excess of anabolism 
over katabolism. 

Protoplasm has essentially the same chemical composi- 
tion everywhere, and in the whole range of green plants 
the same food-materials seem to be required; the six ele- 
ments of which proteids are built are obviously essential 
in quantity as building material, but in addition small 
amounts of Fe, Ca, K, Mg, Na, Cl and Si are in some 
other way equally essential. What part these secondary 
elements play is still largely a matter of hypothesis. 

Regarding metabolism thus crudely as if it were merely 
a congeries of slow chemical reactions, let us see how far it 
conforms to the laws of chemical mechanics we have out- 
lined. 

If the supply of any one of these essential elements 
comes to an end, growth simply ceases and the plant 


No. 502] CHEMICAL MECHANICS IN LIVING PLANT 645 


remains stationary, half-developed. If a Tropæolum in a 
pot be watered with dilute salt-solution, its stomata soon 
close permanently, and no CO, can diffuse in to supply 
the carbon for further growth of the plant. In such a 
condition the plant may remain for weeks looking quite 
healthy, but its growth may be quite in abeyance. 

In agricultural experience, in manuring the soil with 
nitrogen and the essential secondary elements, the same 
phenomenon is observed when there is a shortage of any 
single element. If a continuous though inadequate sup- 
ply of some one element is available then the crop 
development is limited to the amount of growth cor- 
responding to this supply. Agriculturalists have for- 
mulated the ‘‘law of the minimum,’’ which states 
that the crop developed is limited by the element 
which is minimal, 7. e., most in deficit. Development 
arrested by ‘‘nitrogen-hunger’’ is perhaps the commonest 
form of this. All this is of course in accordance with ex- 
pectation on physical-chemical principles. The quantity 
of anabolic reaction taking place should be proportional 
to the amount of actively reacting substances present, and 
if any one essential substance is quite absent the whole 
reaction must cease. It therefore seems clouding a sim- 
ple issue and misleading to say of a plant which, from 
the arrested development of nitrogen-hunger, starts 
growth again when newly supplied with nitrogen, that 
this new growth is a response to a ‘‘nitrogen stimulus.’’ 
It would appear rather to be only the removal of a limit- 
ing condition. 

Let us now move on a stage. Suppose a growing plant 
be liberally supplied with all the thirteen elements that it 
requires, what, then, will limit its rate of growth? Fairy 
bean-stalks that grow to the heavens in a night elude the 
modern investigator, though some hope soon to bring back 
that golden age with overhead electric wires and under- 
ground bacterial inoculations. If everything is supplied, 
the metabolism should now go on at its highest level, and 
quantities of carbon, nitrogen, hydrogen and oxygen sup- 
plied as CO,, nitrates and water will interact so that these 


646 THE AMERICAN NATURALIST [Voi XLII 


elements become converted into proteid, cellulose, ete. 
Now this complex reaction of metabolism only takes place 
in the presence of protoplasm, and a small amount of pro- 
toplasm is capable of carrying out a considerable amount 
of metabolic change, remaining itself undestroyed.. We 
are thus led to formulate the idea that metabolism is es- 
sentially a catalytic process. In support of this we know 
that many of the inherent parts of the protoplasmic com- 
plex are catalytic enzymes, for these can be separated out 
of the protoplasm, often simply by high mechanical pres- 
sure. We know, too, nowadays that the same enzymes 
that accelerate katabolic processes also accelerate the re- 
verse anabolic processes. 

In time a small mass of protoplasm will, while remain- 
ing itself unchanged, convert many times its own weight 
of carbon from, let us say, the formaldehyde (HCHO) 
of photosynthesis to the carbon dioxide (CO,) of respira- 
tion. 

If metabolism is a complex of upgrade and downgrade 
changes catalyzed by protoplasm we must expect the 
amount of metabolism to obey the law of mass and to be 
proportional to the masses of substances entering into the 
reaction. The case when any one essential element is a 
limiting factor we have already considered. When all are 
in excess, then the amount of the catalyst present becomes 
in its turn the limiting factor. Transferring this point 
of view to the growing plant, we expect to find the limited 
mass of protoplasm and its constituent catalysts setting 
a limit to the rate of metabolic change in the extreme case 
where all the materials entering into the reaction are in 

excess. When once this supply is available further in- 
` crease in supplies can not be expected to accelerate the 
rate of growth and metabolism beyond the limit set by the 
mass of protoplasm. This, of course, is in accordance with 
common experience. The clearest experimental evidence 
is in connection with respiration and the supply of carbo- 
hydrates—this, no doubt, because the carbohydrate ma- 
terial oxidized in respiration is normally stored inside 

plant-cells in quantity and can be estimated. When the 


No. 502] CHEMICAL MECHANICS IN LIVING PLANT 647 


supplies for an internal process have to be obtained from 
outside, then we have the complications of absorption and 
translocation to obscure the issue, especially in the case 
of a higher plant. 

Let us first take a case where the carbohydrate supply 
is in excess and the amount of catalytic protoplasm is 
small and increasing. Thus it is in seeds germinating in 
the dark: respiration increases day by day for a time, 
though carbohydrate reserves are steadily decreasing. 
Palladine® has investigated germinating wheat by analy- 
zing the seedlings and determining the increase of the es- 
sential (non-digestible) proteids day by day. The amount 
of these proteids he regards as a measure of the amount 
of actual protoplasm present. Assuming this to be so, 
he finds an approximately constant ratio between the 
amount of protoplasm at any stage and the respiration. 

As germination progresses in the dark the supplies of 
reserve carbohydrate presently fail, and then the respira- 
tion no longer increases in spite of the abundant proto- 
plasm. According to our thesis the catalyst is now in 
excess and the CO. production is limited by the shortage 
of respirable material. 

This second type of case was more completely investi- 
gated by Miss Matthei and myself in working on the 
respiration of cut leaves of cherry-laurel kept starved 
in the dark. For atime the CO, production of these non- 
growing structures remains uniform, and then it begins to 
fall off in a logarithmic curve, so that the course of res- 
piration is just like C in Fig. 1. We interpret both phe- 
nomena in the same way: in the initial level phase the res- 
pirable material in the leaf is in excess, and the amount of 
catalytic protoplasm limits the respiration to the normal 
biological level; in the second falling phase some supply 
of material is being exhausted, and we get a logarithmic 
curve controlled by the law of mass, as much, it would 
seem, as when cane-sugar is hydrolyzed in aqueous solu- 
tion. 

After these two illustrations of the action of the law 

5 Revue gén. de botanique, Tome VIII, 1896. 


648 _ THE AMERICAN NATURALIST [Vor. XLII 


of mass from the more simple case of respiration we re- 
turn to the consideration of the totality of metabolic re- 
actions as exemplified in growth. 

What should we expect to be the ideal course of growth, 
that is, the increase of the mass of the plant regarded 
as a complex of reactions catalyzed by protoplasm? Let 
us consider, first, the simplest possible case, that of a bac- 
terium growing normally in a rich culture solution. When 
its mass has increased by anabolism of the food material 
of the culture medium to a certain amount it divides into 
two. As all the individuals are alike, counting them would 
take the place of weighing their mass. The simplest ex- 
pectation would be that, under uniform conditions, growth 
and division would succeed each other with monotonous 
regularity, and so the number or mass of bacteria present 
would double itself every n minutes. This may be ac- 
cepted as the ideal condition. 

The following actual experiment may be quoted to show 
that for a time the ideal rate of growth is maintained, and 
that at the end of every n minutes there is a doubled 
amount of protoplasm capable of catalyzing a doubled 
amount of chemical change and carrying on a doubled 
growth and development. 

From a culture of Bacillus typhosus in broth at 37° C. 
five small samples were withdrawn at intervals of an 
hour, and the number of bacteria per unit volume deter- 
mined by the usual procedure. The number of organisms 
per drop increased in the following series: 6.7, 14.4, 
33.1, 70.1, 161.0.2 This shows a doubling of the mass 
of bacteria in every fifty-four minutes and is the ease ac- 
tually represented in the strictly logarithmic curve of 
Fig. 2. 

We may quote some observations made by E. Buchner’ 
of the rate at which bacteria increase in culture media. 
Bacillus coli communis was grown at 37° C. for two to 

* Buchner. Zuwachsgrossen u. Wachsthumsgeschwindigkeiten. Leipzig, 

1 


1901. 
° For this unpublished experiment on bacterial growth I am indebted to 
Miss ypon of the Lister Institute of Preventive Medicine. 


No. 502] CHEMICAL MECHANICS IN LIVING PLANT 649 


five hours, and by comparison of the initial and final num- 
bers of bacteria the time required for doubling the mass 
was calculated. Out of twenty-seven similar experiments 
a few were erratic, but in twenty cases the time for 
doubling was between 19.4 and 
24.8 minutes, giving a mean 
of 22 minutes. This produces 
an increase from 170 to 288,000 


in four hours. No possible eul- ‘* 
ture medium will provide for A 
prolonged multiplication of Me 
bacteria at these rates. 

Cohn® states that if division too | 
takes place every sixteen min- 
utes then in twenty-four hours $Ìgo | 
a single bacterium 1 » long will 
be represented by a multitude 3,, | 


so large that it requires i 
twenty-eight figures to express + 


it, and placed end to end they 3 T 
would stretch so far that a È F 
ray of light to travel from one #?° 7 


end to the other would take L 
100,000 years. The potentiali- 
ties of protoplasmic catalysis 
are thus made clear, but the 
actualities are speedily cut short by limiting factors. 

For a while, however, this ideal rate of growth is main- 
tained. At the end of every n minutes there is a doubled 
amount of protoplasm present, and this will be capable 
of catalyzing twice the amount of chemical change and 
carrying on a doubled amount of growth and develop- 
ment. This is what common sense and the law of mass 
alike indicate, and is exactly what this logarithmic curve 
in Fig. 2 expresses. 

This increase of the amount of catalytic protoplasm 
by its own catalytic activity is an interesting phenomen- 
on. In Section K we call it growth, attribute it to a spe- 

° Cohn. Die Pflanze. Breslau, 1882, p. 438. 


(8) 
Houn n 4 5 + 
Fie. 2. 


650 THE AMERICAN NATURALIST [ Vou. XLII 


cific power of protoplasm for assimilation (in the . strict 
sense), and leave it alone as a fundamental phenomenon, 
but are much concerned as to the distribution of the new 
growth in innumerable specifically distinct forms. In the 
Chemical Section they call this class of phenomenon 
“autocatalysis,” and a number of cases of it are known. 
In these a chemical reaction gives rise to some substance 
which happens to catalyze the particular reaction itself, 
so that it goes on and on with ever-increasing velocity. 
Thus, we said that free acid was a catalyst to the hydro- 
lysis of cane-sugar; suppose now that free acid were one 
of the products of the hydrolysis of sugar, then the ca- 
talyst would continually increase in amount in the test- 
tube, and the reaction would go faster and faster. Un- 
der certain conditions this actually happens. Again, 
when methyl acetate is hydrolyzed we normally get 
methyl acohol and free acetic acid. This free acid acts 
as a catalyst to the hydrolysis, and the rate of change 
continually accelerates. Here, if the supply of methyl 
acetate were kept up by constant additions, the reaction 
would go faster and faster with a logarithmic accelera- 
tion giving a curve of velocity identical with Fig. 2, A. 

For a clear manifestation of this autocatalytic increase 
in the plant it is, of course, essential that the supply of 
food materials to the protoplasm be adequate. 

Another case where we might look for a simple form 
of this autocatalytic increase in the rate of conversion of 
food materials to anabolites would be in the growth of a 
filamentous alga, like Spirogyra. Here, as in the bacter- 
ium, all the cells are still capable of growth. In this case 
the food-material needed in greatest bulk is carbon, which 
has to be obtained by photosynthesis. Some experiments 
have been started in the Cambridge Laboratory on the 
rate of growth of Spirogyra in large tubs of water kept 
at different temperatures and with varying facilities for 
photosynthesis and metabolism. Under rather depress- 
ing conditions the Spirogyra took several days to double 
its weight—a rate of metabolism out of all comparison 
slower than that of bacteria. Experiments on these 


No. 502] CHEMICAL MECHANICS IN LIVING PLANT 651 


lines, with the different food materials as limiting factors, 
should give instructive results. 

We turn now to consider the growth of a flowering 
plant. Here conditions are more complex, and we know 
that at the flowering stage or end of the season the 
growth diminishes considerably. This difference from 
a simple alga or bacterium we can only regard as a sec- 
ondary acquisition in relation to the external conditions— 
either a reaction to a present external stimulus or to the 
memory of past stimuli. In a flowering plant, too, all 
the cells do not continue to grow; many cells differentiate 
and cease to grow and also some of the groups of meris- 
tem remain dormant in axillary buds. Clearly the growth 
curve can not continue to accelerate logarithmically, and 
in later phases it must tail off; the ‘‘ grand period’’ which 
growth is said to exhibit is another way of stating this. 
It will, however, be of great interest to us to see what will 
be the form of the curve of growth during the early period 
of development. 

The importance of this class of work has been realized . 
in Geneva, and detailed work is now being done under 
the inspiration of Professor Chodat® in which the curve 
not only of growth (fresh weight) but of the uptake of 
all the separate important elements in selected plants is 
being carefully followed. 

With plants grown in the open, climatic disturbances 
must occur. We shall therefore figure a curve for the 
fresh weight of a maize plant grown in water-culture. 
This is prior to the Geneva work, and due to Mlle. Stef- 
anowska,'!° who has studied also the growth-curves of 
small animals. The first phase of the curve, lasting some 
fifty days, shows strictly uniform acceleration, doubling 

°” Monnier, A. Les matières minérales et la loi d’accroissement des 
végétaux. Geneva, 1905. 

Déléano, N.. Le rôle et la fonetion des sels minéraux dans la vie de la 
plante. Geneva, 1907. 

See also the independent work of Tribot. Comptes rendus de 1’ Acad. 
des Sciences, October 14, 1907. 

Osea dings Comptes rendus de l’Acad. des Sciences, February 1, 


652 THE AMERICAN NATURALIST [ Vou. XLII 


the weight of the plant every ten days (Fig. 3). The 
precise external conditions are not stated. 

In spite of the morphological complexity the autocataly- 
tic reaction of growth is apparently not checked by inade- 
quate supplies before the plant enters rather suddenly 
upon the second phase. Here, from the present point of 
view, we consider that the progress of growth is inter- 
rupted, not by the primary physical-chemical causes, but 
by secondary causes, presumably to be classed in the cate- 
gory of stimulus and reaction. 

The numerous curves for the accumulation of different 
organic and mineral constituents worked out for barley 


A 
~~, ee 
{? a 
bo all 
a / 
3 'g 
Si z a 
i 20 a 
of de : 
Days ° og 20 30 40 $0 G@ Fo Bo 90° 0 
Fic. 3. 


and buckwheat at Geneva are of similar form, but do not 
keep up the uniform rate of doubling so well as does the 
curve of total fresh weight. 

In this connection the tall and dwarf forms of the same 
plant present an interesting problem, and some experi- 
ments have been started on sweet peas at Cambridge. 
At the time of germination the seedlings weigh about 
the same, whereas at the end of the season the weight of 
a tall plant is many times that of a dwarf ‘‘cupid” grow- 
ing alongside under similar conditions. Is the difference 
due to a less vigorous autocatalysis in the dwarf form, 
so that throughout its growth it takes a greater number 


No. 502] CHEMICAL MECHANICS IN LIVING PLANT 653 


of days to double its weight? Construction of the curves 
of growth through the season will show whether it is this 
or some other alteration in the form of the curve. 

I now propose to say a few words about one last point 
in connection with growth considered as a phenomenon of 
catalysis before passing on to deal with the effects of 
temperature. 

Of the metallic elements that are essential for the 
growth of plants some occur in such minute quantities 
that one can only imagine their function is catalytic. If 
iron, for instance, played any part in metabolism which 
involved its being used up in any building material or 
by-product of metabolism, then a larger amount than actu- 
ally suffices should be advantageous. If its function is 
catalytic the iron would go on acting indefinitely without 
being consumed, and so a minute trace might serve to 
carry out some essential, and even considerable, sub-sec- 
tion of metabolism. 

Elements like manganese, magnesium and iron are 
often associated with non-vital catalytic action, and a 
preparation of iron has recently been quantitatively in- 
vestigated which seems to have literally all the properties 
of an organic oxydase from plant tissues."! 

As long ago as 1869 Raulin observed that traces of un- 
essential salts, in particular those of zine, added to the 
culture medium in which he grew the fungus Sterigmato- 
eystis caused a rapid acceleration of the growth rate. 
The time that the mycelium took to double its weight was 
now reduced to a half or even a third. This continued 
enormous effect of so small a trace of substance is pos- 
sibly to be regarded as an added catalyst to the normal 
protoplasmic apparatus. This sort of effect is currently 
labeled ‘‘chemical stimulation’’ and has been interpreted 
as an attempt of the fungus to grow away from an un- 
pleasant environment. To me it looks as if such chem- 
ical stimulation were really another example of the in- 


“Wolff, J. Des péroxydiastases artificielles. Comptes rendus de 
l’ Acad. des Sciences, June 9, 1908. 


654 THE AMERICAN NATURALIST [ Vou. XLII 


judicious extension of the concept of stimulus and re- 
action. 

This effect of zine upon the growth of mycelium has 
recently been verified and extended by Javillier,'? who 
has made comparative cultures with increasing doses of 
zine salt. He grew Sterigmatocystis for four days at 
34° C. in media with graded additions of zine salts. As 
the graphic representation shows, he finds a continuous 


Cw 


i 


a +> 
N 


N 


o a f 


05 ef H 3 7? Ss *6 
port zimne Suiphale uk nilkan. 


Fig. 4. 


regular increase of the number of grams of final dry 
weight with doses up to 0.00001 per cent., and then no 
greater but an equal effect up to 100 times as large a dose. 

This form of curve with uniform rise at first, abrubtly 
changing to a level top, suggests, as I have pointed out 
elsewhere,!* the cutting-off of the primary rising effect by 
a limiting factor. In this case presumably the limit set 
by some other sub-section of the metabolism has been at- 
tained. 


ACCELERATION OF REACTION-VELOCITY BY TEMPERATURE. 


We now turn to consider the fourth and last of the 
principles of chemical mechanics which we might expect 
to find manifested in metabolism. 

It is a universal rule that rise of temperature quickens 
the rate at which a chemical reaction proceeds. Of 
course in some rare conditions this may not be obvious, 
but be obscured by superposed secondary causes; but al- 
most always this effect is very clearly marked. 

Further, the nature of the acceleration is a peculiar 

“Comptes rendus de 1’Acad. des Sciences, December, 1907. 


1 Optima and Limiting Factors. Annals of Botany, Vol. XIX, April, 
1905. 


No. 502] CHEMICAL MECHANICS IN LIVING PLANT 655 


one. Rise of temperature affects nearly all physical and 
chemical properties, but none of these is so greatly 
affected by temperature as is the velocity of chemical re- 
action. Fora rise of 10° C. the rate of a reaction is gen- 
erally increased two or three fold, and this has been gen- 
eralized into a rule by van’t Hoff. As this increase is re- 
peated for each successive rise of 10° C. either by the 
same factor or a somewhat smaller one, the acceleration 
of reaction-velocity by temperature is logarithmic in 
nature, and the curve representing it rises ever more and 
more steeply. Thus keeping within the vital range of 
temperature a reaction with a temperature factor of X 2 
per 10° C. will go sixteen times as fast at 40° C., as at 
0° C., while one with a factor of X 3 will go eighty-one 
times as fast. 

This general law of the acceleration of reactions 
by temperature holds equally for reactions which 
are being accelerated by the presence of catalysts. 
As we regard the catalyst as merely providing 
for the particular reaction it catalyzes, a quick way round 
to the final stage by passing through the intermediate 
stage of forming a temporary addition-compound with the 
catalyst itself, so we should expect rise of temperature 
to accelerate similarly these substituted chemical reac- 
tions. 

If this acceleration is a fundamental principle of chemi- 
cal mechanics it is quite impossible to see how vital chem- 
istry can fail to exhibit it also. | 


ACCELERATION OF VITAL PROCESSES By TEMPERATURE. 

At present we have but a small number of available 
data among plants to consider critically from this point of 
view. But all the serious data with which I am ac- 
quainted, which deal with vital processes that are to be 
considered as part of the protoplasmic catalytic congeries, 
do exhibit this acceleration of reaction-velocity by tem- 
perature as a primary effect.'* 

“A collection of twenty cases, mostly from animal 


Kanitz (Zeits. fiir Elektrochemie, 1907, p. 707), 
ing from 1.7 to 3.3. 


physiology, by 
exhibits coefficients rang- 


656 THE AMERICAN NATURALIST (Vou. XLII 


Let us briefly consider these data. On the katabolic 
side of metabolism we have the respiratory production 
of CO,, and opposed to it on the anabolic side the intake 
of carbon in assimilation. 

As a measure of the rate of the metabolic processes 
constituting growth we have data upon the division of 
flagellates; and finally there is the obscure process of cir- 
culation of protoplasm. 

The intensity of CO, production is often held to be a 
measure of the general intensity of metabolism, but any 
relation between growth-rate and respiration has yet to 
_ be clearly established. Our science is not yet in the stage 
when quantitative work in relation to conditions is at all 
abundant; we are but just emerging from the stage that 
chemistry was in before the dawn of physical chemistry. 

Taken by itself the CO,-production of an ordinary 
green plant shows a very close relation with temperature. 
In the case of the cherry-laurel worked out by Miss 
Matthæi and myself the respiration of cut leaves rises by 
a factor of 2.1 for every 10° C. (See Fig. 5, Resp.) 
This has been investigated over the range of tempera- 
tures from 16° C. to 45° C. At this higher temperature 
the leaves can only survive ten hours in the dark, and 
their respiration is affected in quite a short time, but in 
the initial phases the CO, output has the value of .0210 
gr. per hour and unit weight of leaf, while at 16.2 C. 
the amount is only .0025 gr. CO,. Thus the respiration 
increases over a range of tenfold with perfect regularity 
solely by increase of temperature. No reaction in a 
test-tube could show less autonomy. At temperatures 
above 45° C. the temperature still sooner proves fatal un- 
less the leaf is illuminated so as to carry out a certain 
amount of photosynthesis and compensate for the loss 
of carbon in respiration. Thus, with rising temperature, 
there is at no time any sign of an optimum or of a de- 
crease of the intensity of the initial stage of respiration. 

Here, then, on the katabolic side of metabolism we have 
no grounds for assuming that ‘‘temperature-stimuli’’ are 
at work regulating the intensity of protoplasmic respira- 


No. 502] CHEMICAL MECHANICS IN LIVING PLANT 657 


tion, but we find what I can only regard as a purely phys- 
ical-chemical effect. The numbers obtained by Clau- 
sen!® for the respiration of seedlings and buds at different 
temperatures indicate a temperature coefficient of about 
2.0 for a rise of 10° C. 

To this final process of katabolism there could be no 
greater contrast than the first step of anabolism, the as- 
similation of carbon by the protoplasm as a result of pho- 
tosynthesis. We must therefore next inquire what is the 
relation of this process to temperature. , 

This question is not so simple, as leaves can not satis- 
factorily maintain the high rate of assimilation that high 
temperatures allow. The facts of the case were clearly 
worked out by Miss Matthzi,'® the rate of assimilation 
by cherry-laurel leaves being measured from —6° C. to 
+ 42° C. Up to 37° C. the curve rose at first gently and 
then more and more steeply, but on calculating out the 
values it is found that the acceleration for suecessive rises 
- of 10° C. becomes less and less. Between 9° C. and 19° 
C. the increase is 2.1 times, the highest coefficient 
measured, and exactly the same coefficient as for respira- 
tion in this plant, which in itself is a striking point, 
seeing how different the processes are. (See Fig. 5, 
Assimilation.) 

The decrease of the coefficient with successive rises is 
a state of things which is quite general among non-vital 
reactions. A critical consideration of the matter leads 
one to the conclusion, however, that this failure to keep 
up the temperature acceleration is really due to secon- 
dary causes, as is also the appearance of an optimum at 
about 38° C. Some of these causes, have been discussed 
by me elsewhere,'’ and I hope to bring a new aspect of the 
matter before the section in a separate communication. 
The conclusion formerly come to was that probably in 
its initial stages assimilation at these very high tempera- 

* Landwirtschaftliche Jahrbücher, Bd. XIX, 1890. 

* Phil. Trans. Roy. Soc., Ser. B, Vol. CXCVII, 1904. 


* Optima and Limiting Factors. Annals of Botany, Vol. XIX, April, 
1905. 


658 THE AMERICAN NATURALIST [ Vou. XLII 


tures started at the full value indicated by a theoretically 
constant coefficient, but that the protoplasm was unable 
to keep up the velocity, and the rate declined. It must 
be borne in mind here that quite probably no chloroplast 


> [Respu um 


Devise onj 


> 
X 


Y O Oe: 30 AS Ot 
Fre: 5. 


since the first appearance of green cells upon the earth 
had ever been called upon for anything like such a gas- 
tronomic effort as these cherry-laurel leaves in question. 
It is not to be wondered that their capacities speedily 
declined at such a banquet, and that the velocity-reaction 
of anabolic synthesis traces a falling curve in spite of the 
keeping up of all the factors concerned, to wit, tempera- 
ture, illumination, and supply of CO,. This decline is not 
permanent, but after a period of darkening the power of 
assimilation returns. Physical-chemical parallels can 
easily be found among cases where the accumulation of 
the products of a reaction delays the apparent velocity 
of the reaction, but this complicated case may be left for 
further research. 

In relation to assimilation, then, we must say that 


No. 502] CHEMICAL MECHANICS IN LIVING PLANT 659 


owing to secondary causes the case is not so clear over 
the whole range of temperature as that of respiration, 
but that at medium temperatures we have exactly the 
same relation between reaction-velocity and temperature. 

We may consider now some data upon the combined 
net result of anabolic and katabolice processes. Such total 
effects are seen in their clearest form among unicellular 
saprophytic organisms for which we have a few data. 
Mile. Maltaux and Professor Massart'® have published a 
very interesting study of the rate of division of the color- 
less flagellate Chilomonas paramaecium and of the agents 
which they say stimulate its cell-division, in particular 
aleohol and heat. 

They observed under the microscope the time that the 
actual process of division into two took at different tem- 
peratures. From 29 minutes at 15° C. the time dimin- 
ished to 12 minutes at 25° C., and further to 5 minutes 
at 35° C. The velocities of the procedure at the three 
temperatures 10° C. apart will therefore be in the ratio of 
1 : 2.4 :5.76, which gives a factor of 2.4 for each rise of 
10° C. (See Fig. 5, Division.) 

Now we are told by the investigators that at 35° C. 
Chilomonas is on the point of succumbing to the heat, so 
that the division rate increases right up to the death 
point, with no sign of an optimum effect. Below 14° C. 
no observations are recorded. 

Here, then, we have throughout the whole range ex- 
actly the same primary temperature relation exhibited by 
the protoplasmic procedure that we should expect for a 
chemical reaction in a test-tube. 

This division phase is only a part of the life-cycle of 
the flagellate, and between division it swims about anabol- 
izing the food material of the medium and growing to its 
full size ready for the next division. One wishes at once 
to know what is the effect of the temperature upon the 
length of the life-cycle. Is the whole rate of metabolism 
quickened in the same way as the particular section con- 


18 Maltaux and Massart. Recueil de 1’Institut botanique ranila 
Tome VI, 1906. ; 


660 THE AMERICAN NATURALIST [Von XLII 


cerned with actual division? Of course a motile flagellate 
ean not be followed and its life-cycle directly timed but 
the information was obtained by estimating carefully 
what percentage of individuals was in a state of actual 
division at each temperature. It was found that always 
4 per cent. were dividing, whatever the temperature. 
This proves that the whole life-cycle is shortened in ex- 
actly the same proportion as the process of division at 
each temperature, and that it is just twenty-five times as 
long. Therefore the life-cycle is 125 mins. at 35° C, 
and 725 mins. at 15° C., so that here, again, we have 
the physical-chemical relation with a factor of 2.4 for 
each rise of 10° C. 

In this paper of Maltaux and Massart these relations 
are not considered as the manifestations of physical-chem- 
ical principles, but are regarded as reactions to stimuli; 
and the paper contains a number of experiments upon the 
effect of sudden changes of temperature upon the occur- 
rence of division. As far as one can make out from in- 
spection of the scattered literature, it does seem estab- 
ished that sudden changes of temperature act as stimuli 
in the strict sense of the word. In many investigations 
one finds it stated that a quick change of temperature pro- 
duced a certain reaction which a slow change of tempera- 
ture failed to evoke. Usually all the phenomena are 
treated in terms of stimulation, and the absence of reac- 
tion with slow change of temperature is regarded as sec- 
ondary. Were it not for the specific stimulatory effects 
of quick change, which are not difficult to comprehend as a 
phenomenon sui generis, I hardly think so general a tacit 
acquiescence would have been extended by botanists to 
the view that all enduring changes of velocity of metab- 
bolism brought about by lasting changes of temperature 
are stimulatory in nature. 

No determination of the rate of development of bacteria 
through a very wide range of temperature seems to have 
been made. There are various incidental experiments 
which indicate values about 2 for the coefficient of in- 
crease of metabolism for a rise of 10° C. 


No. 502] CHEMICAL MECHANICS IN LIVING PLANT 661 


I am not acquainted with any data for the growth rate 
of whole flowering plants at different temperatures: Of 
course the case of growth most usually measured in the 
laboratory, namely, where one part of a plant extends 
at the expense of the reserves stored in another part and 
there is a decrease, not an increase, of total dry weight, 
is not the type of growth we have to deal with. Even 
for simple elongation of a shoot at different temperatures 
we have but few data. Those of Koppen (1870) gener- 
ally quoted are wildly irregular, and in many cases it is 
clear that the growth-extension of complex structures is 
a process which proceeds by spasms rather than smoothly. 

The rate of movement of circulating protoplasm in- 
creases rapidly with temperature, but Velten’s numbers 
do not give an obvious logarithmic curve. If we con- 
fine our attention to the values for 29° C. and 9° C. we 
do find, however, that the velocity increases about two- 
fold for each rise of 10° C. being 10 mm. at 9° C. and 
40 mm. at 29° C. 

Taken altogether these various data clearly support 
the hypothesis that temperature accelerates vital proc- 
esses in the same way as it does non-vital chemical re- 
actions, that is, logarithmically by an approximately con- 
stant factor for each rise of 10° C.; and, further, it ac- 
celerates them to the same extent; that is, that the factor 
in question has values clustering about 2-3.19 

To make these similarities more significant I ought to 
point out that no other properties of matter are acceler- 
ated to anything like this extent by rise of temperature. 
Most reactions increase in velocity by no less than 10 per 
cent. per degree rise of temperature; a most marked 
effect, and yet there is no generally accepted explanation 

of this almost universal phenomenon. By the kinetic 
_ theory of gases each rise of a degree in temperature in- 
creases the movements of the gas-molecules, so that the 

*Tt has been proposed to use the size of the temperature coefficient 
to settle whether a process like the conduction of an impulse along a 


nerve is a chemical or a physical process. See Lueas, Keith. Journal of 
Physiology, Vol. XXXVII, June, 1908, p. 112. 


662 THE AMERICAN NATURALIST [ Vou. XLII 


number of collisions between them is greater, but only 
about 4 per cent. greater. With rise in temperature, too, 
the viscosity of a solution diminishes, so that there is less 
resistance to internal changes; but this only to the extent 
of 2 per cent. per degree. The degree of ionization also 
increases, but only extremely little, so that no change of 
known physical properties will explain the phenomenon. 
Various hypotheses which need not detain us have been 
put forward. 

Unexplained though it may be, yet the quantitative 
treatment of the subject is clear enough and, I think, as 
cogent in the living organism as in the test-tube. If so, 
we may consider ourselves now justified in separating off 
from the realm of stimulation yet a third class of causal 
connection, namely, that between temperature and gen- 
eral intensity of vital processes. 


CONCLUSION. 

In this attempt to assert the inevitableness of the action 
of physical-chemical principles in the cell, I have not 
ventured upon even the rudiments of mathematical form, 
which would be required for a more precise inquiry. Bio- 
chemistry is indeed becoming added to the ever-increasing 
number of branches of knowledge of which Lord Bacon 
wrote: 

Many parts of nature can neither be invented with sufficient subtility, 
nor demonstrated with sufficient perspicuity, nor accommodated unto 
use with sufficient dexterity, without the aid and intervening of the 
mathematies. 

In this sketch which I have had the honor of outlining 
before you I have critically considered but few points. 
I have rather endeavored to distribute imperfect data 
in the perspective in which they appear from the point of 
view of one who seeks to simplify phenomena by extend- 
ing the principles of chemical mechanics as far as pos- 
sible into the domain of vital metabolism. Much critical 
quantitative work has yet to be done before the whole 
becomes an intelligible picture. 

To me it seems impossible to avoid regarding the fun- 


No. 502] CHEMICAL MECHANICS IN LIVING PLANT 663 


damental processes of anabolism, katabolism and growth 
as slow chemical reactions catalytically accelerated by 
protoplasm and inevitably accelerated by temperature. 
This soon follows if we once admit that the atoms and 
molecules concerned possess the same essential properties 
during their brief sojourn in the living nexus as they 
do before and after. 

Perhaps the more real question is rather as to the 
importance and significance of this point of view. Pro- 
toplasmic activity might be something so much per se, 
and the other factors of the nature of stimuli might be 
superposed so thickly upon that substratum which should 
be dominated by simple principles of chemical mechanics 
that for practical purposes the operations of the latter 
would be so overlaid and masked as to be neglible. A 
survey of this field, however, seems to show that this is 
not so, and that the broad action of the law of mass and 
the acceleration of reaction-velocity by temperature are 
obviously responsible for wide ranges of phenomena. 

Now the conception at the bottom of these principles 
is that of reaction-velocity, and the conclusion of the 
whole matter is that the physiologist must frankly take 
over from physical chemistry this fundamental concep- 
tion. Under definite conditions of supply of material 
and temperature there is a definite reaction-velocity for 
a given protoplasm, and the main factors that alter the 
rate of metabolism, viz., heat, nutrition and traces of im- 
purities are exactly the factors which affect the velocity of 
reactions in vitro. 

Working on this basis we no longer need the vague un- 
quantitative terminology of stimulation for the most fun- 
damental of the observed ‘‘responses’’ to external con- 

=No general treatment of the physiology of plants has yet been at- 
tempted in terms of reaction-velocity. Czapek, however, in the introduction 
to his stupendous Biochemie der Pflanzen, Vol. I, 1905, does draw attention 
to the conception of ‘‘reaction-velocity’’ and refers to the standard litera- 
ture on this subject and on catalysis, though direct application is not made 
to the plant. Cohen (Physical Chemistry for Physicians and Biologists, 


English edition, 1903) considers in detail some biological applications of 
the acceleration of reactions by temperature. 


664 THE AMERICAN NATURALIST [ Vou. XLII 


ditions. Three sets of phenomena we have observed 
which, though usually treated in the category of stimula- 
tion, draw a clearer interpretation from the conception of 
reaction-velocity. These were: (1) the relation of devel- 
opment to the absence or deficit of single essential food 
constituents; (2) the occasional striking effect of minute. 
traces of added foreign substances upon the whole rate 
of growth and metabolism; and (3) the general doubling 
of the activity of vital processes by a rise of 10° C. 

The next higher stratum of principles should be the 
complications introduced by limiting factors which inter- 
rupt the extent of the manifestations of these principles 
and by various correlations, as, for example, that by which 
the reaction-velocity of one catabolic process might with- 
draw the supply of material needed for full activity of 
another different process. To this sort of relation may 
be attributed that phenomenon so characteristic of the 
more complex vital processes and quite unknown in the 
inorganic world, namely, the optimum. 

Finally, superposed upon all this comes the first cate- 
gory of phenomena that we are content still to regard as 
stimulatory. From the point of view of metabolism and 
reaction-velocity many of these appear very trivial, 
though their biological importance may be immense. 
Think how little the tropistic curvatures of stems and 
roots affect our quantitative survey; yet a little rear- 
rangement of the distribution of growth on the two sides 
of an organ may make the difference between success and 
failure, between life and death. 

From our present point of view vision does not extend 
to the misty conceptions of stimulation upon our horizon. 
We may therefore postpone speculation upon the mechan- 
ical principles governing them and await the time when 
by scientific operations we shall have reduced to law and 
order the intervening region, which we may entitle the 
chemical substratum of life. This done we may ven- 
ture to pitch our laboratory a march nearer to the phe- 
nomena of protoplasmic irritability and make direct at- 
tack upon this dominating conception, the first formidable 
bulwark of vital territory. 


THE DESICCATION OF ROTIFERS 


D. D. WHITNEY 
CoLD Spring HARBOR, Lone IsLAxND, N. Y. 


THE general statement often found in text-books that 
‘‘Adult rotifers can survive prolonged desiccation and 
resume active life when again placed in water,’’ seems to 
have been made without sufficient warrant. 

While working with the rotifer, Asplancha brightwellii, 
my attention was repeatedly called to the fact that when 
the water became sufficiently evaporated so as to expose 
only a portion of the body of the rotifer to the air it 
never recovered when placed again in a larger quantity 
of water and soon died. Doubt as to the truth of the 
general statement regarding desiccation naturally arose 
and in consequence a series of experiments were carried 
out to test the matter. 

Forty-five species of rotifers that were collected in the 
various ponds and pools in the vicinity of Cold Spring 
Harbor, New York, were dried at room temperature, 
from a few hours to several days, during the months of 
July and August. They were dried without being ex- 
posed to direct sunlight in a hollow ground slide, upon 
filter paper, in sediment taken from the water in which 
the rotifers lived, and also in sediment mixed with sand. 
Masses of the water plants, Lemna, Myriophyllum and 
others among which many species lived were also dried. 
After the water seemed to have been completely evapo- 
rated fresh spring water was added and those animals 
that ever revived did so within ten to twenty minutes 
after the water was added. Drying the rotifers in masses 
of sediment and in sediment mixed with sand was found 
to lead to more recoveries. 

In all experiments many species were dried in the same 
lot and in nearly all of them these were mixed with roti- 
fers which were known to withstand drying: If none of 

665 


666 THE AMERICAN NATURALIST [ Vou. XLII 


the animals revived when water was added it was as- 
sumed that the method of drying of the lot was imper- 
fect but if, on the other hand, those animals that were 
known to be able to withstand drying revived, when water 
was added, the method of drying of the lot was deemed 
satisfactory. It may be possible, however, that the indi- 
viduals of different species, since they vary greatly in 
size and form, require different methods for being suc- 
cessfully dried and again revived. But if revival after 
desiceation is of general occurrence for adult rotifers the 
various methods of drying used in the experiments ought 
to have given a fair percentage of positive results. 

The individuals of some of the species were obtained 
in countless thousands, either in nature or in artificial 
cultures, others were less numerous and only a few thou- 
sand or a few hundred individuals were obtained. In a 
small number of species only a few individuals were 
found and used in the experiments. 

Jennings' classifies the rotifers in five orders: (1) 
Bdelloida with two families; (2) Seisonacea with one 
family; (3) Rhizota with three families; (4) Ploima with 
eighteen families; and (5) Scirtopoda with one family. 

In the experiments performed no individuals were 
used belonging to the order Seisonacea which contains 
all marine forms, nor were there used any individuals of 
the order Rhizota which contains all the fixed forms, 
Repr tatives were used from one family of the order 
Bdelloida, from fifteen families of the order Ploima, and 
from the one family of the order Scirtopoda. Thus the 
forty-five species used represented seventeen of the 
twenty-one families in the three orders just mentioned. 

The following species were used in the experiments: 
Order 1. Bdelloida. 

Family 1. Philodinade. 
Species. Rotifer vulgaris, R. macrurus; Philodina roseola; 
citrina. 


Order 4. Ploima. 
Suborder 1. Illoricata. 


1 AMER. Nat., Vol. XXXV, p. 725. 


No. 502] THE DESICCATION OF ROTIFERS 667 


Family 1. Microcodontide. 
Species. Microcodon clavus.* 
Family 2. Asplanchna 
Species. PEES brightwellii.? 
Family 3. Synchætadæ. 
Species. Syncheta tremula, Polyarthra platyptera? 


Species. Triarthra longiseta’ 
Family 5. Hydatinadæ. 

Species. Hydatina senta* 
Family 6. Notommatadæ. 


Species. Taphrocampa saundersie, Notommata y 
Copeus pachyurus, Furcularia gracilis, F: 7 
Eosphora aurita, Diglena i 


Suborder 2. Loricata. 
Family 1. Rattulidæ. 
Species. Mastigocerca mucosa, M. bicornis; M. ———.° 
Family 2. Dinocharidæ. 
Species. Dinocharis tetractis, Scaridium longicaudatum, 


Family 3. Salpinadæ. 


Species. Euchlanis dilatata’ E. triquetra. 
Family 5. Cathypnadæ. 
Species. Cathypna leontina‘ Distyla gissensis? D. 
stokesii; Monostyla lunaris? M. bulla; M. quadriden- 
ata. 


Family 6. Coluridæ. 
Species. Colurus bicuspidatus, Metopidia lepadella? M. 
triptera, M. 
Family 7. Pterodinadæ. 
Species. Pterodina patina, P. reflexa.* 
Family 8. Branchionidæ. 
Species. Branchionus bakeri; B. urceolaris, B. pala; 
B. angularis, Noteus quadricornis. 
Family 10. Pleosomadæ. 
Species. Pleosoma truncatum? (?). 
Order 5. Scirtopoda. 
Family Pedalionadæ. 
Species. Pedalion mirum? 


? Few thousand individuals used in the experiments. 

? Many thousand individuals used in the experiments. 

* Probably less than a hundred Sphere used in the experiments. 
* Few hundred individuals used in the experiments. 


668 THE AMERICAN NATURALIST [ Vou. XLII 


This list is far from being complete but it represents 
so many families of the free swimming rotifers upon 
which the general statement in regard to desiccation is 
supposedly based that the results obtained ought to ‘indi- 
cate whether the phenomenon of desiccation is wide- 
spread among the common forms. 

Philodina roseola and Philodina citrina were the only 
forms of the forty-five experimented upon which could 
successfully withstand desiccation and resume normal 
activities when again placed in water. Some of them re- 
mained ten days in small masses of débris, 1-2 mm. in 
diameter, which were as thoroughly dried as possible in 
the laboratory atmosphere. Those that were dried in 
the sun never revived when again placed in water. This 
may have been due to a too complete desiccation or to the 
high temperature, which was usually about 45° C. 

The cuticle in the Philodinadz is less specialized in the 
structure than in any of the other families of the three 
orders, and as this structural character is of great im- 
portance in the present system of classification the family 
may be considered the lowest or most primitive of all the 
twenty-one families. It is interesting to note, however, 
that some of the species of another genus, Rotifer, of the 
same family, can not withstand complete desiccation. In 
several experiments in which the four species of Philo- 
dina and Rotifer were mixed together in the débris, sedi- 
ment or water plants, all four species would revive if the 
material in which they were contained was not completely 
dried, but only the two species of Philodina revived when 
the drying was complete. Systematists separate the two 
genera by the position of the eyes but evidently there is 
a more fundamental difference than this which means life 
and death in times of drought. 

The common misconception regarding desiccation may 
probably have arisen, in part, from the fact that when 
mud or sediment from ponds in which rotifers live is 
dried living rotifers appear after a few hours when water 
is added to the sediment. These living rotifers prob- 


No. 502] THE DESICCATION OF ROTIFERS 669 


ably develop however from the ‘‘winter eggs’’; thick 
shelled fertilized eggs, which in some cases are known to 
withstand prolonged desiccation. 

During this summer some winter eggs of Asplanchna 
brightwellii and Hydatina senta, which had been laid in 
June, were kept in water taken from the culture® jars 
until August 3. Then they were taken out with a little 
sediment and allowed to dry. On August 5, the sediment 
was apparently thoroughly dried. On August 10 spring 
water was added and at the end of twenty-four hours 
several small Asplanchna were swimming about in the 
water. Later young Hydatina were found in the water. 
The eggs seem to vary much in the length of time re- 
quired for them to hatch, some not hatching for three 
or four days after being placed in spring water while 
others hatch within twenty-four hours. This may be due 
to differences in the rate of rapidity in which water pene- 
trates the egg membranes. In sections of the winter eggs 
of Hydatina senta it is very noticeable that the thickness 
of the outer egg membrane varies greatly in different 
eggs. 

On August 4 ten to fifteen cubic centimeters of mud 
and sediment were collected in a finger-bowl from the 
pond in which Asplanchna brightwellii, Branchionus 
urceolaris, and Pedalion mirum, were living and allowed 
to dry in the sun. The next day the mud was thoroughly 
dried so it would readily crumple between one’s fingers. 
In this condition it was kept until August 10 when the 
finger-bowl was filled with spring water. On the follow- 
ing day several individuals of each of the above three 
species were swimming about in the water. 

When ponds and pools in which rotifers live are in the 
process of drying up the water becomes so foul by the 
decomposition of dead plants and animals that all the 
rotifers of some species die before the pool is completely 
dried. If, on the other hand, rotifers are kept in the 
laboratory in very clean water which is allowed to slowly 

Jour. Exper. Zool., Vol. V, p. —. 


670 THE AMERICAN NATURALIST [Vou. XLII 


evaporate they all die, presumably of starvation. It is 
also interesting to note that some pools do not become 
dry during the summer but the rotifer fauna changes 
completely several times during the season. A small 
pond in this vicinity was teeming with Asplanchna 
brightwellii and Branchionus urceolaris during the 
early part of July but by the middle of August not an 
individual of either species could be found in it. Indi- 
viduals of Pedalion and Polyarthra were very numerous 
at this time but in the latter part of August not one 
could be found. The pond was now teeming with 
Branchionus angularis, B. pala and Triarthra longiseta 
but no individual of the first four species named above 
was present. 

In a ease like this desiccation could play no part in the 
preservation of the species and they could only be saved 
by winter eggs. 

Some winter eggs of Asplanchna brightwellii which 
were laid in June in artificial cultures were buried July 
3 in an ice house upon a cake of ice where the temperature 
was 1-2° C. On August 7 they were removed from the 
ice house to ordinary room temperature and the old cul- 
ture water replaced by fresh spring water. At the end 
of forty hours several young Asplanchna were swimming 
about in the water. 

Many other winter eggs which were laid at the same 
time as the above lot but which had remained in the labo- 
ratory at room temperature in a bottle containing water, 
taken from the culture jar in June were placed in fresh 
spring water. In many cases within an hour the thick 
outer egg membrane had cracked open and exposed about 
a fourth of the thin inner membrane which surrounded 
the embryo. The history of some of these eggs was fol- 
lowed and it was found that they produced normal young 
animals on the following day. The swelling and crack- 
ing open of the thick outer membrane is obviously due to 
the sudden great change of osmotic pressure which is 


No. 502] THE DESICCATION OF ROTIFERS 671 


brought about by removing the eggs from a somewhat 
foul and cencentrated culture to fresh spring water. 

This process of causing winter eggs to develop in the 
summer is very likely the same that occurs in nature in 
the spring months. During the fall and winter the pools 
become free from abundant animal and plant forms and ` 
the accompanying products of decomposition by the fre- 
quent floodings by rains and the low temperature. In 
the spring the heavy rains flood the pools again and the 
osmotic pressure of the water is so much lower than it 
was in the previous summer that the eggs absorb water 
enought to rupture the thick outer membrane and stimu- 
late the embryos to growth. As the temperature becomes 
favorable they develop and the life cycle is completed. 

From the foregoing observations it seems probable 
that desiccation of the adult rotifers followed by revival 
is not of widespread occurrence in the group and is not 
the means resorted to by most species for tiding over 
unfavorable periods. Survival is due in most eases to 
the winter eggs which can withstand both desiccation and 
a low temperature. 


ON THE HABITS AND THE POSE OF THE SAU- 
ROPODOUS DINOSAURS, ESPECIALLY 
OF DIPLODOCUS 


DR. OLIVER P. HAY 


WASHINGTON D. C. 


To most persons the habits of living animals are more 
interesting than is their anatomy. The same is probably 
even more true with respect to the extinct animals. How- 
ever, when it comes to determining the habits of extinct 
animals, their aquatic or terrestrial habitat, their modes 
of progression, their bearing on their limbs, their food 
and their ways of procuring it, their modes of attack and 
defense against their enemies, their manner of reproduc- 
tion, etc., we meet with many difficulties. 

The Sauropoda, and especially the species of Diplo- 
docus, offer a fine illustration of the difficulties men- 
tioned. Were they aquatic, or terrestrial, or amphib- 
ious? Did they affect dry lands, or swamps, or rivers 
and lakes? Did they eat vegetable food or did they prey 
on other animals? Did they chew their food or did they 
bolt it? Did they bring forth living young or did they 
lay immense eggs? Did they make bold attacks on their 
enemies or were they timid and cowardly creatures? 
Did they walk only, or swim only, or did they employ 
both methods of transporting their huge bodies? If 
they walked, was it on all four legs or on the hinder ones 
only? If on all four, did they carry their bodies high 
above the ground, after the manner of the ox and the 
horse, or did they carry them low down, like the croco- 
diles, perhaps dragging their bellies on the ground? 

To some of these questions more or less definite 
answers have been made and accepted; others remain 
unanswered. It is pretty well agreed that a part of their 
time was passed in the water; that they could swim 

672 


No.502] HABITS OF SAUROPODOUS DINOSAURS 673 


readily; that they walked mostly on all fours; that to 
some extent at least they went about on land; that their 
food was mainly, if not wholly, vegetable; mani that they 
had imperfect or no means of chewing it. 

We are assisted in understanding the habits of these 
creatures by a knowledge of the nature of their environ- 
ment. And this we must determine from the character 
of the deposits in which their bones are discovered and 
from the kinds of animals and plants accompanying 
them. Investigation has shown that their remains occur 
in sandstones and clays which were certainly laid down 
in fresh waters having no great amount of motion. The 
accompanying animals are other dinosaurs, some herbiv- 
orous, others carnivorous; besides crocodiles, turtles, 
freshwater fishes and freshwater shells. Some of the 
plants that occur in the deposits certainly lived in fresh 
water. 

Hatcher’ has discussed at length the nature of the 
region in which the species of Diplodocus and their allies 
lived, as well as the habits of the Sauropoda in general; 
and the present writer agrees with him on most points. 
Hatcher believed that the Atlantosaurus beds were de- 
posited, not in an immense freshwater lake, as held by 
some geologists, but over a comparatively low and level 
plane, which was occupied by perhaps small lakes con- 
nected by an interlacing system of river channels. The 
climate was warm and the region was overspread by lux- 
uriant forests and broad savannas. The area thus oc- 
cupied included large parts of the present states of Colo- 
rado, New Mexico, Utah, Montana, and the Dakotas. In 
his memoir on Diplodocus, Hatcher? compares the condi- 
tions prevailing in that region during the Upper Jurassic 
to those now found about the mouth of the Amazon and 
over some of the more elevated plains of western Brazil. 
In such regions the rivers, fed from distant elevated 
lands, must have been subject to frequent inundations. 

*Mem. Carnegie Mus., II, 1903, pp. 54-67. 

* Mem. Carnegie Mus., I, p. 60 


674 THE AMERICAN NATURALIST (Vou. XLII 


The beds of the streams were continually shifting, and 
there existed numerous abandoned channels that were 
filled with stagnant water. An animal that lived in such 
a region would be compelled to adapt itself to a more or 
less aquatic life, and this adaptation would be reflected 
to a greater or less extent in the structure of the animal. 
Marsh had concluded from the position of the external 
nares of Diplodocus that it was addicted in some measure 
to an aquatic existence. The feet too are of rather 
peculiar structure, the inner toes being strongly clawed, 
the outer toes greatly reduced; but the meaning of this is 
differently interpreted. 


Tue Foop or DreLopocus 


The particular sort of food eaten by the species of Dip- 
lodocus is unknown, but nobody doubts that it was vege- 
table. The teeth were pencil-like in form and they were 
entirely confined to the front of the jaws. By general 
consent, they could have been employed only for prehen- 
sion of food, not at all for its mastication. Hatcher sug- 
gested that the teeth might have been useful in detaching 
from the bottoms and shores the tender and succulent 
aquatic and semi-aquatic plants that must have grown 
there in abundance. Osborn? says that ‘‘the food prob- 
ably consisted of some very large and nutritious species 
of water plant. The anterior claws may have been used 
in uprooting such plants. . . . The plants may have been 
drawn down the throat in large quantities without masti- 
cation.” In a restoration of Diplodocus by Mr. Charles 
W. Knight* the animal is represented as standing on its 
hind legs and preparing to bite off the terminal bud of a 
towering cyead. Holland® thinks that the teeth were 
better adapted for raking and tearing off from the rocks 
soft masses of clinging alge than for securing any other 
forms of vegetable food now represented in the waters of 
the world. 

* Mem. Amer. Mus. Nat. Hist., I, p. 214. 


* Scientific American, XCVI, 1907, p. 485. 
* Mem. Carnegie Mus., II, p. 240. 


No. 502] HABITS OF SAUROPODOUS DINOSAURS 675 


To the present writer the suggestion of Dr. Holland 
has in it more of probability than any of the others pre- 
sented. If the food-plants sought by Diplodocus had 
been large and such as required uprooting by the great 
claws of the reptile the prehension and manipulation of 
the masses would have been liable to break the slender 
teeth and would certainly have produced on them per- 
ceptible wear. The upper teeth of the original of Marsh’s 
‘figures on Plate XXV of the Dinosaurs of North Amer- 
ica® show no wear, so far as the writer can determine. 
The mandibular teeth are not well exposed to view. 

With respect to Osborn’s theory, it is well to take into 
consideration also the probable ability of the reptile to 
digest great masses of undivided and unmasticated vege- 
tation. Against the theory suggested by Knight’s res- 
toration it may be urged that the teeth, pointed or slightly 
chisel-shaped, are poorly adapted for cropping leaves 
and great buds; most of all, the teeth have spaces be- 
tween them, like the teeth of a great comb, an arrange- 
ment not favorable to their functioning as cutting instru- 
ments. The teeth could hardly have been used for 
scraping alge from rocks, either, for that usage would 
have produced evident and rapid wear. It is more 
probable that the food consisted of floating alge and of 
plants that were loosely attached to the bottoms of stag- 
nant bayous and ponds. Hatcher has reported’ the 
finding of the seeds and the stems of a species of Chara 
near the Marsh quarry, where many Sauropoda have 
been found. This alga, it seems to the writer, would 
have been admirably adapted to the needs of Diplodocus. 
It could be easily gathered into the mouth as the reptile 
swam or crawled lazily about or rested itself and re- 
tracted and extended its long neck. The long and highly 
vaulted palate would have permitted a considerable mass 
to be collected, out of which, by pressure of the tongue, 
the superfluous water might have been squeezed between 


* (Cat. No. 2672, U. S. Nat. Mus.) 
* Mem. Carnegie Mus., II, p. 63. 


676 THE AMERICAN NATURALIST [ Vou. XLII 


the spaced teeth. In addition to various alge there were 
probably other floating plants. 


Tue Posture or DIPLODOCUS 


Marsh presented no restoration of Diplodocus, but he 
did furnish restorations of Brontosaurus; and he stated 
that he regarded it as representing the general form and 
proportions of the Sauropoda. In this figure Bronto- 
saurus is shown as walking with the body high above the 
ground and with the limbs, especially the hinder ones, 
about as straight as they are in the elephant. 

So far as the bearing of Brontosaurus and Diplodocus 
on their limbs is concerned, Marsh’s example has been 
almost slavishly followed ever since. No one, so far as 
the writer knows, has ventured to defend in print a more 
erocodilian posture. Osborn’ grants that there is room 
for wide differences of opinion as regards the habits and 
means of locomotion of these gigantic animals and states 
that some hold the opinion that on land at least these 
reptiles had rather the attitude of the alligator. The 
same writer says in Nature, vol. 73, 1906, p. 283, that Dr. 
Matthew and Mr. Gidley have maintained the latter view. 
However, the trend of opinion seems to have been in the 
opposite direction. Osborn? suggested that Diplodocus 
might lift its fore limbs from the ground and support 
itself on the hinder legs and the tail. This idea has 
found expression in Knight’s restoration referred to 
above. Osborn’s general notion of Diplodocus seems, 
however, to be that it was essentially an aquatic animal, 
long, light-limbed, and agile, and capable of swimming 
rapidly by means of its great tail, provided, as he 
thought, with a vertical fin; yet occasionally going about 
on land. Hatcher’? opposed the view that Diplodocus 
was aquatic; and he showed that there is no evidence of 
the presence of a vertical fin. The compression of the 

rotten XXII, 1905, p. 376. 


. Amer. Mus. Nat. Hist., I, p. 213. 
x Mer. Carnegie Mus., II, 1903, p. 59. 


No. 502] HABITS OF SAUROPODOUS DINOSAURS 677 


centra where the fin is supposed to have been situated 
seems to have been slight, and the neural spines are not 
higher than elsewhere. The present writer finds neither 
in the feet nor in the tail any special arrangements for 
swimming. For navigation in its restricted waters no 
fin was needed. Almost any colubrid snake makes fair 
progress in the water, notwithstanding the absence both 
of a compressed tail and of a vertical fin. 

Hatcher’s final view does not, after all, appear to have 
been greatly different from that of Osborn. He held that 
Diplodocus, as well as most of the Sauropoda, were essen- 
tially terrestrial animals, but that they passed much, 
perhaps most, of their time in shallow water, where they 
could wade about and search for food. He believed that 
they were ambulatory, but quite capable of swimming. 
Hatcher’s language does not necessarily imply that these 
animals walked about after the fashion of quadrupedal 
mammals, but his restorations show plainly that such was 
his conception. 

This conception has prevailed in the plaster reproduc- 
tions of the skeleton of Diplodocus which have been sent 
abroad by the Carnegie Museum and_set up in London, ` 
Berlin and Paris; and in the small plaster restorations 
issued by the American Museum of Natural History. 
However, the limit of quadrupedal erectness, rigidity, 
rectangularity, and rectilinearity has quite been reached 
in the skeleton sent by the last mentioned institution to 
the Senckenberg Museum, at Frankfort-on-the-Main. In 
this case the poor beast is made to stand straight-legged 
and almost on the tips of its digits. On the other hand, 
the American Museum’s skeleton of Brontosaurus, a 
much larger and heavier reptile and one sorely needing 
the mechanical advantage of straight legs, in case it had 
to bear its body free from the ground, has been presented 
to the modern world as having been decidedly bow-legged. 

To the present writer it appears that the mammal-like 
pose attributed to the Sauropoda is one that is not re- 
quired by their anatomy and one that is improbable. 


678 THE AMERICAN NATURALIST [ Vou. XLII 


The current conception is one that is easily accounted for. 
Before exact knowledge of these reptiles had been gained, 
it was known that the dinosaurs of the other groups, 
herbivorous and carnivorous, walked erect, after the man- 
ner of birds. It was indeed necessary, on account of the 
length of the fore limbs, to place the Sauropoda on all 
four feet; but analogy caused it to be supposed that the 
limbs were disposed, with reference to the vertical plane 
of the body, similarly to those of the bipedal dinosaurs. 
The conception of a creeping dinosaur was hardly to be 
entertained. The straight femora of these reptiles, having 
the head and the great trochanter moderately developed, 
lent probability to the idea. 

If the straightness of the femora is relied on to support 
the correctness of the prevailing restorations of the 
Sauropoda we may call attention to the equally straight 
femora of sphenodon and of the lizards. Notwithstand- 
ing the great size of the carnivorous dinosaur Allosaurus 
and the fact that the whole weight of its body was com- 
monly borne by the hinder limbs alone, its femora are con- 
siderably bent. The prominence and the height of the 
great trochanter of the Sauropoda do not appear to be 
such as to have prevented the femora from standing out at 
right angles with the body. Both the head of the femur 
and the acetabulum were doubtless invested with much 
cartilage, so that we can not now be wholly certain about 
their form and fitting. The same may be said regarding 
certain other articulations of the limbs. Hatcher’! has 
spoken of the character of the articulations and he has 
expressed the opinion that the habitual support of the 
body in the air could not have.failed to produce closely 
applied and well-finished articulations, and Osborn had 
previously expressed the same idea.12 There is indeed 
a great difference between the articulations of the limbs 
of the Sauropoda and those of the Theropoda, such as 
Allosaurus and Ceratosaurus. 

“u Mem. Carnegie Mus., I, p. 59. 

2 Bull. Amer. Mus. Nat. Hist., X, p. 220. 


No. 502] HABITS OF SAUROPODOUS DINOSAURS 679 


Osborn'® has found in the large preacetabular process 
an argument in favor of the ability of Diplodocus to ele- 
vate the anterior part of its body. However, Trachodon, 
which habitually walked on its hind legs has a very insig- 
nificent preacetabular process. The crocodiles have a 
strongly developed process in front of the acetabulum. 

It appears to the writer that the structure of the feet 
of the Sauropoda indicates that the digits were directed 
somewhat outward, instead of directly forward, as they 
are placed in the restorations. The strongly developed 
inner digits would then have come more effectively into 
contact with the ground than the much reduced outer 
digits and would have been employed by the animal as a 
means of pushing itself along. In case the lower end of 
the radius is placed in front of the ulna, as represented 
by Hatcher ** it appears probable that the foot would be 
directed more strongly outward than is shown in his 
restoration.‘® 

The writer is not aware that any one has held that the 
Sauropoda could not, at least while resting, assume a 
crocodile-like posture, with the abdomen on the ground 
and the limbs extended outward on each side. If such 
a position is admitted as possible, the arguments derived 
from the anatomy in favor of an erect mode of walking 
are greatly weakened. If such a pose was not assumed, 
what was the pose? Did Diplodocus and Brontosaurus 
lie down on their sides, as an ox or a horse does when 
sleeping? Or did they lie prone, with the limbs drawn 
up under them, as a dog sometimes does? These posi- 
tions appear to be improbable. It is worth considering 
too what disposition Diplodocus made of its elephantine 
legs while it was swimming with the agility that has been 
imputed to it. | 

The weight of Diplodocus and of Brontosaurus fur- 
nishes a strong argument against their having had a 

13 Mem, Amer, Mus. Nat. Hist., I, p. 210. 

“ Mem. Carnegie Mus., II, p. 73, Fig. 1. 

3 Op. cit., Pl. VI. 


680 THE AMERICAN NATURALIST [ Vou. XLII 


mammal-like carriage. There will be little dissent from 
the view that these animals inhabited a country in which 
marshy lands abounded and that they passed the most of 
their time in the vicinity of bodies of water. As to 
weight, Marsh estimated that that of Brontosaurus was 
more than twenty tons. Each footprint was thought to be 
about a square yard in extent. The pressure was there- 
fore about 1,100 pounds on each square foot of the 
ground. What progress could such enormous animals 
have made through morasses and along mud-depositing 
rivers, in case they carried themselves as they are repre- 
sented in the restorations? Without doubt, they would 
soon have become inextricably mired and would have 
perished miserably. 

Osborn'® has suggested that Camarasaurus, another 
sauropod was accustomed to wading about in rivers 
where the bottoms were sandy and firm. The habits of 
Diplodocus could have differed little from those of 
Camarasaurus. It is difficult to understand why an 
animal whose immediate ancestors must have walked 
about in a crocodile-like manner, an animal that was 
stupid and probably slow of movement, an animal which 
could by means of its long neck reach up from the bot- 
tom many feet to the surface and from the surface many 
feet to the bottom—why such a reptile should need to de- 
velop the ability to walk along river bottoms like a 
mammal. Furthermore, it seems somewhat overgener- 
ous to impute to a reptile so many and so diverse activi- 
ties as swimming with great facility, walking on river 
bottoms and on the land with mammal-like gait, and on 
occasion erecting itself on its hinder legs after the man- 
ner of a bird, in order to crop the foliage from the tops of 
high trees, when this reptile was sixty feet long, weighed 
many tons, had a brain little larger than one’s two thumbs 
placed side by side, and was provided with a feeble dental 
apparatus with which to gather food wherewith to sup- 
port its huge body, and that food of a sort that yielded 
little energy in proportion to its bulk. 

* Bull. Amer. Mus. Nat. Hist., X, p. 220. 


No.502] HABITS OF SAUROPODOUS DINOSAURS 681 


The writer’s conception of Diplodocus is that it was 
eminently amphibious, that it could swim with consider- 
able ease, and that it could creep about on land, with 
perhaps laborious effort. When feeding it must have 
swam or crept lazily about, gathering in floating plants 
and such as were attached loosely to the bottom. If any 
plants that were relished grew at some depth they could 
be reached by the long neck; or, if there was foliage 
twenty feet above the water it could be as easily gath- 
ered in. That a Diplodocus ever stood on its hind lgs is 
hardly more probable than that crocodiles may perform 
the same feat. 

The large size of Diplodocus does not preclude the 
possibility that it could creep about on the land. Croco- 
dylus robustus, of Madagascar, is said to attain a length 
of 10 meters, and yet it doubtless is able to walk as other 
crocodiles walk. The limb bones of Diplodocus and of 
Brontosaurus are proportionally as large as those of 
crocodiles. 

It seems to the writer that our museums which are 
engaged in making mounts and restorations of the great 
Sauropoda have missed an opportunity to construct some 
striking presentations of these reptiles that would be 
truer to nature. The body placed in a crocodile-like 
attitude would be little, if any, less, imposing than when 
erect; while the long neck, as flexible as that of an ostrich, 
might be placed in a variety of graceful positions. 


SHORTER ARTICLES AND CORRESPONDENCE 
JUVENILE SUBSTITUTES FOR SMOKING TOBACCO 


Nearly every boy has the desire to smoke and while many 
perhaps begin with tobacco itself, many more probably experi- 
ment with other substances of vegetable origin which burn well 
and yield readily the desired smoke so that the appearances, at 
least, of the act of smoking are produced. The knowledge of 
such substitutes in a particular locality is usually extensive and 
widespread, being the subject of serious conference and debate 
among the youthful inhabitants. Very little, if any, of this 
tradition is recorded, and it seems perhaps a matter of some 
botanical interest that it should be. In some ways, the practise 
of boys in thus providing a substitute bears a singular re- 
semblance to that of the less civilized peoples or communities 
more or less isolated from tobaceo-producing centers. 

My own juvenile knowledge was obtained in eastern Connecti- 
cut between thirty and forty years ago. In those days there 
were still many umbrellas with rattan (Calamus rotang?) ribs. 
Short pieces of these, being porous, on being set afire at one end, 
a matter of some difficulty, allowed the smoke to be drawn 
through in sufficient quantities to be blown out through the 
mouth, but the smoke was hot and biting and the rattan was kept 
alight with difficulty. Later, I learned the virtues of the more 
generally used substitutes, hay-seed, sweet-fern and mullein. 
The hay-seed was usually procured from the floors of the hay 
barns and consisted of the more or less ripened florets of timothy 
(Phleum pratense) and redtop (Agrostis sp.) It was usually 
more or less carefully sifted and smoked in a clay pipe or packed 
in paper shells to imitate cigarettes. This was before the days 
of the universal use of hand-rolled cigarettes and no such papers 
were available, so we used a fairly stiff white paper, rolled it 
about a cylindrical piece of wood of desired length and diameter, 
fastening the free edge by means of home-made starch paste. 
When these were dry, they were carefully stuffed with the hay- 
seed and the ends carefully, if not skilfully, folded in. Very 
commonly, however, the ends came undone during the smoking 
and the fine hay-seed made a disagreeable mouthful. A more 

682 


No. 502] SHORTER ARTICLES AND CORRESPONDENCE 683 


popular filling consisted of the leaves of the sweet-fern (Myrica 
asplenifolia). The leaves were selected when green and fragrant, 
carefully dried in the sun or in the oven, until brittle, then thor- 
oughly pulverized by rubbing between the hands, and finally 
sifted through a coarse sieve. This was then packed tight in 
cigarette shells, and sweet-fern cigarettes required some skill. 
The making of high-grade cigarettes of this kind was one of my 
specialties, and one summer I drove a thriving trade in them, 
disposing of a considerable number at the remunerative price of 
ten for one cent. The lower leaves of the common mullein (Ver- 
bascum Thapsus) were gathered chiefly as they were found dried 
on the plant, roughly pulverized and smoked in a clay pipe. 
They were supposed to closely resemble real tobacco and were the 
preparatory stage to genuine smoking. Often some small boy 
was inveigled into smoking fine-cut tobacco of the ‘‘Durham”’ 
or ‘‘Lone Jack’’ type under the impression that he was simply 
indulging in a pipe of mullein. The resulting sickness, as a rule, 
undeceived him and he realized too late that he had been made 
the victim of a joke more practical than pleasant. : 

For the long-cut tobacco, we found a fair substitute, at least in 
appearance, in the brown and dried ends of corn silk, but it was 
never so very popular with us. I have found on questioning, that 
these same substitutes were known to the generation preceding 
mine and that they are equally well known to the generations 
coming on to fill our places. I have also learned of other sub- 
stitutes not known to us as well as a widespread knowledge of 
some of those mentioned. 

I find that there is a widespread use of tea and ground coffee 
for pipe smoking, and some use even of ground cinnamon. , The 
older youth often take to cubebs, following the officinal use of 
the same. A use seems also to be made of the porous internodes 
of the grape-vine, as we used rattan, and even of tightly rolled 
tubes of cinnamon stick. I have also been told that some boys 
roll paper about the sticks of ‘‘punk’’ used to touch off fire 
crackers on the Fourth of July, and light and smoke them. 

Inquiring of the boys in California, I find that they use corn 
silk and various leaves for pipe smoking. The leaves of maple, 
grape, fig, rose and willow are commonly employed. Perhaps 
the most popular of all are the leaves of the worm-wood (Arte- 
misia heterophylla) which is common on most hillsides and gives 
a pleasing aromatic smoke. In many places, the old fallen leaves 


684 THE AMERICAN NATURALIST [ Vou. XLII 


of the blue gum (Eucalyptus globulus) is a favorite. The leaves 
of yerba santa (Eriodictyon californicum) is smoked to cure 
colds and also by the boys for the pure joy of smoking. The 
leaves of the California bay (Umbellularia californica) are often 
used in the same ways. I am informed by Dr. H. M. Hall that 
the composite Atrichoseris platyphylla is called ‘‘ Tobacco weed’’ 
by the boys of Palo Verde, in the Colorado Desert of California 
and is in decided favor with them for smoking. This plant is 
decidedly rare to the botanist, but after heavy rains it becomes 
plentiful in sandy places and its broad basal leaves are well 
adapted to being rolled into ‘‘cigars.’’ 

Dr. G. H. Shull informs me that the leaves of the American 
pennyroyal (Hedeoma pulegioides) is smoked by the boys in 
some parts of Ohio. 

The wild species of Nicotiana have furnished and still do 
furnish the smoking materials of certain aboriginal peoples from 
the neighborhood of Oregon south to Chile, but there is no record 
of their having been used by juveniles of the white races. I 
learn, however, from Professor R. H. Forbes, of the University 
of Arizona, that the ‘‘wild tobacco’ of the neighborhood of 
Tueson, which, however, is Nicotiana glauca, the tree tobacco, is 
smoked by boys and without injurious effect. 

The above facts are probably but a few of those on this subject 
which may be gathered and I trust that others may take suffi- 
cient interest to add to the list. 

WILLIAM ALBERT SpTCHELL. 

UNIVERSITY OF CALIFORNIA, 

BERKELEY, CALIFORNIA. 


NOTES AND LITERATURE 


HEREDITY 


Recent Studies in Human Heredity—Must the fallacy always 
persist that all ancient and powerful families are necessarily 
degenerate? As long ago as 1881, Paul Jacoby wrote a book? 
to prove that the assumption of rank and power has always been 
followed by mental and physical deteriorations ending in sterility 
and the extinction of the race. By collecting together all evi- 
dence supporting his preconceived theory, by tracing only the 
well-known families in which pathological conditions were heredi- 
tary, by failing to treat of dozens of others whose records would 
not have supported his thesis, by saying everything he possibly 
could that was bad about every one (following always the hostile 
historians), by ignoring everywhere the normal and virtuous 
members, he was able to present what was to the uninformed an 
apparently overwhelming array of proof. In regard to the 
injustice of this one-sided picture I have already had some- 
thing to say in ‘‘Mental and Moral Heredity in Royalty,’ first 
published some six years ago. 

A further study based upon Jacoby’s unsound foundations 
has recently come to my notice, and although a well-made book 
containing an interesting series of 278 portrait illustrations, is 
necessarily quite as misleading as the older structure on whic 
it rests. The main idea of Dr. Galippe is to show that the great 
swollen protruding underlip which descended among the Haps- 
burgs of Austria, Spain and allied houses, and also the protrud- 
ing underjaw (prognathisme inférieur), are stigmata of de- 
generacy, and to demonstrate this he places beside his portraits, 
quotations from the writings of Jacoby. 7 

Galippe uses no statistical methods, not even arithmetical 
counting, and appears to be totally ignorant of English bio- 
metric writings. His general conclusions about the causes of 
degeneracy (aristocratic environment, ete.) are quite as mis- 

* Etudes sur la sélection chez l’homme. Paris, 1881, 2d ed., 1904. 

? Popular Science Monthly, August, 1902-April, 1903. Also extended in 
book form, New York, Holt, 1906. 

*V. Galippe. L’héredité des stigmates de dégénérescence et les familles 
souveraines. Paris, 1905. 


685 


686 THE AMERICAN NATURALIST [Vou. XLII 


leading and unfounded as those of Jacoby, and I fear he could 
not even prove that the anatomical peculiarities are really 
stigmata of degeneration at all. 

If abnormal mouths, noses and ears are to be proved the 
stigmata of degenerate or criminal types it is necessary to prove 
by biometrical methods, a correlation between the bodily 
anomalies on one hand, and the existence of psychic defect on 
the other. Galippe does not attempt to show such a correlation. 

I have taken all the cases available, and divided Galippe’s 
portraits into three classes, those in which the ‘‘lip’’ is 
‘‘marked,’’ those in which it is ‘‘slight’’ and those in which 
it is ‘‘absent.’’ I have tried correlating these 205 cases with 
the mental and moral grades which I had previously obtained 
for these individuals; but I find that any correlation must be 
slight and difficult to prove without much larger data. For 
instance, of the distinctly inferior individuals 25 show the ‘‘lip ”’ 
in a ‘‘marked’’ degree, against 20 in whom it is ‘‘absent’’; 
while of the notably superior persons 22 have the ‘‘marked lip” 
against 21 in whom it is ‘‘absent.’’ It may be similar to the 
slight correlation that is now thought to probably exist between 
genius and insanity. But this is not like saying that genius is 
insanity. 

Many of Galippe’s portraits labeled FE es inférieur”? 
strike the reader as showing nothing peculiar in any way, others 
nothing more than a heavy underjaw, a common characteristic 
of the old royal personages, which so far from being a sign of 
degeneracy may as likely be associated with their general 
strength of character and determination of will. 

But the most misleading side of Galippe’s work, in which he 
also follows Jacoby, is his constant repetition of the word sterility 
and his frequent statements that noble and illustrious families 
thus find their natural end. The chief cause of this common 
mistake has arisen from following down, from ancient times 
to the more recent, the various dynasties in the male lines of 
primogeniture. In an appendix to Galton’s ‘‘Natural Inheri- 
tance,’’ 1889, this question is discussed, and it is there shown 
that all male lines, including the surnames of commoners, tend 
to diminish merely from the law of chance. This is because 
whenever all girls are born in any branch the name is lost abso- 
lutely, and can never be recovered. If the daughters marry 
and have children, the germ plasm is still transmitted, though 


No. 502] NOTES AND LITERATURE 687 


the name is no longer the same. The old dynasties, Plantagenet, 
Stuart, Romanoff, Vasa, ete., have become extinct in one sense, 
although not in another. If certain royal families have gone, 
what is to be said with regard to the following facts. 

The male lines of all the present reigning families of Europe 
are carefully traced in the opposite direction, that is back to 
their earliest noble ancestors, in a most carefully compiled book 
by Dr. Kamil von Behr.* 

With the exception of the present reigning family of Sweden, 
all have been princes, counts or dukes far into the remote past. 
These show from 20 to 33 generations of noble blood, in the 
direct male lines. The following is a list of the present royal 
families with the earliest authentic dates of their nobility. An- 
halt 1059 A. D., Austria (Lorraine) 940 A. D., Baden 962 A. D., 
Bavaria 829 A. D., Belgium 1009 A. D., Denmark 1088 A. D., 
Great Britain 1009 A. D., Greece 1088 A. D., Hesse-Cassel 846 
A. D., Hesse-Darmstadt 846 A. D., Italy (Savoy) 959 A. D., 
Liechtenstein 1133 A. D., Mecklenburg-Schwerin 960 A. D., 
Mecklenburg-Strelitz 960 A. D., Netherlands 992 A. D., Norway 
1088 A. D., Portugal 1009 A. D., Prussia 1061 A. D., Reuss 1122 
A. D., Rumania 1009 A. D., Russia 1088 A. D., Saxe-Coburg- 
Gotha 1009 A. D., Saxony 1009 A. D., Schaumburg-Lippe 1121 
A. D., Schwarzburg 1114 A. D., Spain 861 A. D., Sweden 1810 
A. D., Waldeck 940 A. D., Wiirtemberg 1110 A. D. When one 
considers that they married practically always within their own 
ranks, one can easily see that the present reigning families are 
descended from thousands upon thousands of counts, dukes, 
princes, kings and emperors. That all this blue blood has not 
produced sterility is easily seen by a glance at the ‘‘ Almanach 
de Gotha’’ or any of the books containing lists of the many 
children who have recently been born to royal families. 

It is my own belief that much of the causation underlying 
historical records may be elucidated by the statistical method, if 
all cases for or against a certain theory be impartially recorded, 
and then even a simple arithmetical count be taken. The higher 
statistical methods (biometrical) may be useful for further re- 
finement, but even the most simple rules of arithmetic would 
prevent one going quite as far astray from the truth as Jacoby 
and Galippe have done in their one-sided and utterly unjust 
arraignment of royal families. It is like picturing all million- 
a der in Europa regierenden Fürstenhäuser. 2d ed., Leipzig, 


688 THE AMERICAN NATURALIST (Vou. XLII 


aires corrupt and dishonorable. Truly these slanderers of 
royalty, because they have a certain scientific affiliation, are all 
the more to be dreaded; furthermore, they cast discredit on the 
whole hope of any elucidation of history along biological lines. 

In contrast to books of this sort, one gladly takes up several 
recent memoirs emanating from University College, London. In 
the first of the publications of the new Eugenics Laboratory, E. 
Schuster and Miss Elderton,® to obtain data bearing on the in- 
heritance of ability, have made a statistical study of Oxford 
class lists and of the schools of Harrow and Charterhouse. By 
analyzing the academic standing of different members of the 


- same family, they show that the resemblance between father and 


son is represented approximately by the coefficient r= .30, in 
all their tables. The various coefficients for fraternal resem- 
blance, range around r= .40. They are perfectly in accordance 
with the theoretical expectancy propounded by Galton for his 
law of ancestral heredity. They are also in accordance with the 
correlations found in ‘‘Heredity and Royalty.’’ 

Other coefficients found by Pearson and his students for 
various physical and psychical measurements are higher than 
these, ranging around .40 to .50 for parental and .50 to .60 for 
fraternal correlation. In an appendix to this memoir of 
Schuster and Elderton, Pearson takes up the question of the 
size of the coefficients and shows that the class lists of Oxford, 
Harrow and Charterhouse represent probably a selected group, 
in point of ability, in which case their variability would be 
reduced and also the correlation coefficients. After making for 
this a reasonable, though rough, correction he concludes that 
the coefficients of Schuster and Elderton are in close accord with 
those heretofore found by this same school of investigators. 

David Heron? from the same laboratory contributes a first 
study of the inheritance of the insane diathesis. It is indeed 
a ‘‘First Study’’ in more senses than one, for not only is it the 
first work on this question from the Eugenics Laboratory, but 
it is not too much to say that it is the first attempt to treat the 
whole subject in an exact and satisfactory manner from the 

* Eugenics Laboratory Memoirs. I, The Inheritance of Ability. By 


Edgar Schuster, M.A., and Ethel M. Elderton. London, Dulau and Co., 
Soho Square, W., 1907. 


* Eugenics Laboratory Memoirs. II, A First Study of the Statisties of 
Insanity and the Inheritance of the Insane Diathesis. By David Heron, 
M.A., London, Dulau and Co., Soho Square, W., 1907. 


No. 502] NOTES AND LITERATURE 689 


statistical standpoint. Heron, on this point, makes the follow- 
ing just and timely complaint. 


A careful examination of the annual Reports of the Asylums of 
Great Britain and Ireland has led to the conviction that no data at 
present published would enable the statistician to reach any quantitative 
results as to the inheritance of any single form of brain disease? Even 
medical treatises as a rule go no further than stating the percentage of 
eases in which insanity or some other want of mental balance has been 
recorded in the family history. As long as we do not know the total 
number in each class of relatives of the insane person and the exact 
brain defect from which they have suffered; as long as we do not know 
the total number of relatives of a random sample of the sane population 
and the exact forms of neurosis or brain disease from which they too 
have suffered, any attempt at a full treatment of the “ inheritance of 
insanity ” is from the statistical standpoint idle. What advantage can 
possibly arise from telling us that an insane person has so many 
alcoholic uncles if we do not know either the total number of his parents 
brothers and sisters, or the percentage of aleoholic members in the same 
grade of relationship of a sane individual of the same social class? 

e solution of this difficulty, and the present writer believes 
ot many other difficulties in the statisties of insanity, is to establish a 
General Register of the Insane for preservation in the office of the 
Lunacy Commissioners. 


Heron’s own work is based upon an analysis of 331 family trees 
provided by Dr. A. R. Urquhart, physician superintendent of 
the James Murray’s Royal Asylum, Perth, Scotland. The co- 
efficient of parental inheritance is found to be about r= .50 and 
fraternal resemblance r= .45 — .55. These are in close accord 
with other physical and mental measurements. The author is 
obliged to make several assumptions in regard to the general 
population in order to complete his calculations, so that his 
figures must be regarded as only a first approximation. The 
work is certainly in the right direction and it is to be hoped 
that all alienists will carefully read this valuable memoir. 

Miss Elderton and Pearson’ have published a measure of the 
resemblance of first cousins, especially in such characteristics as 
general health, intelligence, success, temper, temperament (re- 
served or expressive, sympathetic or callous, excitable or calm). 
Their correlation coefficients are not very uniform, but they 
show clearly enough a high degree of cousin resemblance, r 

* Eugenics Laboratory Memoirs. IV, On the Measure of the Resem- 
blance of First Cousins. By Ethel M. Elderton, assisted by Karl Pearson 
London, Dulau and Co., Soho Square, W., 1907. 


690 THE AMERICAN NATURALIST (Vou. XLII 


ranging around .27. The results are taken from Pearson’s 
‘Family Records’’ and there is something in the method which 
would seem to artificially increase the apparent resemblance. 
Different people have been asked to give their opinions about 
cousins whom they may happen to know. Some judges would 
naturally be more generous than others in their estimates. It is 
easy to see that, by cynicism on the one hand, and optimism on 
the other, many cousins would be taken in pairs out of the 
medium groups, where they very likely belong, and where they 
would lower the correlation coefficient, and placed in pairs either 
above or below the mean, where they would improperly raise the 
coefficients. Actual bodily measurements would not be suscep- 
tible of error from this source and these physical measurements 
they have attempted to obtain. So far, the latter. records are 
insufficient for full publication, but as far as they go they show 
roughly a very high value for the coefficient r. 

The authors ‘‘conclude accordingly, from the present results, 
that for the purposes of eugenics, cousins must be classed as 
equally important with uncles and aunts, and that they may 
eventually turn out to be as important as grandparents.’’ One 
suggestion is that any scientific marriage enactments would 
equally allow or equally forbid marriage between first cousins, 
as between grandparents and grandchild, uncle and niece, or 
aunt and nephew. 

One of their conclusions regarding alternate inheritance con- 
firms my own general contention of alternate inheritance in 
mental and moral traits, a fact on which I laid so much stress 
in tracing the pedigree of all the royal families. They state 
that ‘‘a determinantal theory of heredity, emphasizing alternate 
inheritance, must take precedence of any theory of simple blend- 
ing for the bulk of the characters here dealt with.’’ 

The next two memoirs to which I shall make reference,’ are 
especially important and timely, owing to the wide-spread prev- 
alence of the idea that tuberculosis is an infectious disease and 
not especially hereditary. I have even seen it printed in large 

* Drapers’ Company Research Memoirs, Studies in National Deterioration. 
II, A First Study of the Statistics of Pulmonary Tuberculosis. By Karl 
Pearson, F.R.S. Dulau and Co., London, 1907. Drapers’ Company Re- 
search Memoirs. III, A Second Study of the Statistics of Pulmonary 
Tuberculosis: Marital Infection. By the late Ernest G. Pope. Adirondack 
Cottage Sanitarium, Saranac Lake, N. Y. Edited and revised by Karl 


Pearson, F.R.S., with an appendix on assortative mating from data re- 
duced by Ethel M. Elderton. Dulau and Co., London, 3908. 


No. 502] NOTES AND LITERATURE 691 


type in publications emanating from public health leagues that 
‘‘Tuberculosis Is Not Hereditary.’’ I do not know on what 
scientific basis such a dogma rests. 

Professor Pearson has found cogent proof in the first of these 
studies that the phthisical diathesis is just as hereditary as any 

uman characteristic we know about. It would take too much 
space to completely review this paper. In a few words it may 
be enough to say that he does not jump at the conclusion that 
correlation coefficients necessarily show heredity. The question 
of infection through members of the same family living in close 
eontact is discussed at length; but the analysis reveals no evi- 
dence that direct infection is in any way important, as compared 
to the heritable diathesis. 

For instance, in his second paper on this same subject he finds 
that if a husband is tubereular, then there is a probability that 
the wife will also be found tuberculous, and vice versa, but this 
correlation is not nearly sg high as that between brothers and 
brothers, sisters and sisters, and brothers and sisters. Yet 
opportunities for direct infection in the case of husband and 
wife are of course vastly greater than among brothers and 
brothers, ete., who by the time of the average age of onset of 
the disease (twenty to thirty years) have already ceased to live 
in the same households. 

The question of assortative mating comes in to explain a cer- 
tain amount of this observed correlation between husband and 
wife. Assortative mating is a convenient name for the tend- 
ency of like to mate with like, aside from any question as to 
what causes may bring about the similarity in question. 
It is a popular belief that tall men marry short women, and 
blonds are attracted by brunettes, but the truth of the matter 
seems to be quite the reverse. In nine series of physical char- 
acteristics the correlations of resemblance between husband and 
wife have been found to range between r= .20 and r—.28. 
For physical characteristics nine series show a range between 
r==.11 and r=.48, with an average of r= .24.° The corre- 
lation coefficient for insanity between husband and wife is 
fos. 

“Unless, therefore, any characteristics show a relationship between 
husband and wife markedly greater than .20 to .25 it would be very 


***Second Study of the Statistics of Pulmonary Tuberculosis,’’ cited 
above, p. 22. 


692 THE AMERICAN NATURALIST (Vou. XLII 


difficult to assert that this resemblance is due to other causes than 
those assortative processes which have just been shown to produce quite 
a sensible degree of resemblance in husband and wife.” 

Pearson is ‘‘prepared to accept with some reservation a 
sensible but probably not very large infective action from the 
available statistics of pulmonary tubereulosis.’’ The question 
of assortative mating is an important one, and a knowledge of 
the amount to be allowed under various circumstances seems to 
me to be a necessary adjunct for recorrecting all the correla- 
tion coefficients of heredity which have so far been obtained by 
the London workers. Their coefficients agree fairly well, but 
they are all distinctly higher than the theoretical—fraternal 
are about .50 to .60 instead of the theoretical .40; paternal .40 
to .50, the theoretical being .30; and so with the most remote 
relationships, especially the first cousin resemblances. 

t is evident that if assortative mating be in general the 
strong force that Pearson has shown it to be, then it must in 
most investigations raise the correlation coefficients for heredity. 
To make this clear—tall fathers have on the average tall sons, 
though their average height is less than that of the fathers, 
due to the principle of regression, but now if it happens that all 
the tall fathers have tall wives, then the sons will get an added 
height from the influence of the tall mothers and will seem to 
resemble their fathers more than they do from the real paternal 
influence alone. 

Among royal families assortative mating is a disturbing factor 
is at a minimum, for here the marriages are so often arranged 
by others than the parties most concerned, or are the result of 
some important state policy, that the question of individual 
selection is nearly, though I believe not quite, eliminated. This 
may be the reason why the coefficients for heredity found in the 
study of royalty are so much nearer the theoretical. 

It may be well, in closing, to say a word about the general 
question of correlation coefficients as affording a proof of the 
influence of pure heredity. It may be asked—do the coefficients 
really prove anything more than a general resemblance between 
relatives? May this not be due to heredity in some cases and 
to environment in others, or a combination of both, in most cases? 
Personally I do not feel that the coefficients alone afford all the 
desired proof. Analysis of the material, separating the cases 
into classes in which environment has had greater or less time 


No. 502] NOTES AND LITERATURE 693 


to act,!° or into classes which are known to have lived in different 
environments, or comparing contrasted children within the same 
family, with contrasts in the ancestry of these (alternate in- 
heritance) or other schemes which seek to find measurable in- 
fluence of the environment factor, are, some or all, necessary for 
any final proof. 

What the correlation coefficients do show is this, that if hered- 
ity be the great preponderating force, creating individual dif- 
ferences between man and man, the coefficients that have been 
found are in substantial agreement with what they should be. 

Further refinement is wanted, especially as to the effect of 
assortative mating, and the shape of the curve of distribution 
for psychic characters, when selected classes are taken. 

Mendel’s laws, so important to the horticulturists, and to the 
breeder of superficial traits in fancy strains of domesticated 
animals, has not been shown to have any bearing on human 
heredity, at least as concerns important characteristics." The 
general rough principle of alternate inheritance in human hered- 
ity, leads, however, to the hope that a further study of this ques- 
tion may bring out certain ‘‘unit characters,’’ more or less 
marked, so that here in the end there may be harmony between 
the two unfriendly schools, the Mendelian and the Biometrical. 

F. A. Woops. 


ORNITHOLOGY 


Riddle on the Cause of the Production of ‘‘Down’’ and other Down- 
like Structures in the Plumages of Birds..—A connection is here 
traced between the rate of growth and the character of the 


V This method is employed by E. L. Thorndike in his excellent study of 
the ‘‘ Measurement of Twins.’’ Arch. of Philos., Psychol. and Scientific 
Methods, No. 1, New York, 1905. Also in some of the University College, 
London memoirs. 

“Tt has been claimed to govern the inheritance of certain rare 
anomalies, albinism, abnormal hands, ete., also eye color (C. B. and G. C. 
Davenport, Science, Vol. XXVI, p. 589) and facial peculiarities of Red 
Indians when crossed with the Scotch (G. P. Mudge, Nature, November 7, 
1907). 

Riddle, Oscar. The Cause of the Production of ‘‘Down’’ and other 
Down-like Structures in the Plumages of Birds. Biological Bulletin, Vol. 
XIV., No. 3, February, 1908, pp. 163-176. 


694 THE AMERICAN NATURALIST [Vou. XLII 


structure in feathers. In a former paper? the same author 
showed that a feather is made up of a series of faint ‘‘funda- 
mental bars,’’ due to the manner of deposition of the feather sub- 
stance. These bars are somewhat analogous to the annual rings 
of growth in the trunk of a deciduous tree, the tree rings showing 
the amount of annual increase in the tree trunk, while the bars 
mark the daily growth in the production of the feather. The 
demarkation of the fundamental bars is due to the period of 
reduced blood-pressure during the early morning hours (1-6 
A.M.) of each day during the growth of the feather, and the 
defective transverse lines to malnutrition, or to reduced nutri- 
tion. As shown by Jones,* the nestling down or neossoptile is 
not a distinct and complete feather growth, but merely an apical 
segment of the first definitive feather, the first down being ‘‘the 
plumulaceous tip of the first definitive feather.’’ The constric- 
tion between the two parts Riddle considers to be another 
variety of this same defect, due to insufficient nutrition. At the 
time of the hatching of the egg the down portion of the down 
feather is completed, and the shaft portion immediately succeeds, 
at a time when the whole source of food-supply is changed, and 
assimilation impaired by the intervention of a new source of 
alimentation. While this is obvious, experiments have been 
conducted to show the effects of underfeeding at the critical stage 
in the bird’s life, and it has been found that a bird in the 
downy condition can thus be made to wear its downy plumage 
for months after it should have given place to the definitive 
feathers. ‘“‘The ‘quill’ region is a part of the feather which 
‘normally’ almost refuses to grow; by reducing the food-supply 
during and after its formation further growth may be absolutely 
inhibited or stopped.’’ - 
From the experiments here related, the author concludes that 
the down portion of feathers is due to poor nutritive conditions, 
and that ‘‘ The formation of the quill is probably the direct result 
of a progressive diminution of an already lessened food-supply.’’ 
Apparently all this bears upon the ‘‘how’’ rather than the 
‘‘why’’ of feather production and feather structure, and is not 
to be given a too-sweeping application. In other words, that in 
the development of a pennaceous feather, the formation of its 
different parts—the pennaceous, the downy, and the quill por- 
7A Study of Fundamental Bars in Feathers. Biol. Bull., Vol. XII, 
February, 1907, pp. 165-174. Noticed in The Auk, January, 1908, p. 98. 


No. 502] NOTES AND LITERATURE 695 


tions—is not to be ascribed to the varying conditions of nutrition 
of the individual during the growth of a particular feather. 
While we would accept the hypothesis that varying blood- 
pressure during the twenty-four hours may give rise to the phe- 
nomena of ‘‘fundamental bars’’ and ‘‘defective lines,’’ that 
defective areas may result from malnutrition, and that under- 
feeding may retard feather development, we can hardly conceive 
that we have here a full explanation of the differentiation of a 
feather into pennaceous, downy, and quill portions, or that the 
widely differing plumage structure shown by owls, pigeons and 
hummingbirds is merely a matter of nutrition, in its ordinarily 
accepted sense. In a moulting bird, for example, there may be 
hundreds of feathers in process of growth at the same time, and 
feathers in all possible stages of development. If reduced nutri- 
tion is necessary for the formation of the downy portions of the 
feather, and still further reduction of nutrition for the forma- 
tion of the quill, how can all of these processes of feather growth 
take place, through experiment or otherwise, in the same indi- 
vidual at the same time, as we know is the case in an actively 
moulting bird? Each feather has its definite function, and its 
predestined form and character, in accordance with its position 
on the bird’s body; and feathers differ in character in different 
birds in accordance with their rôle in nature, depending upon 
whether they are owls, or swifts, or pigeons, or penguins, ete. 
Evidently the nutrition of the single feather and the nutrition 
of the individual bird are not necessarily one and the same thing; 
while defective or insufficient nutrition of the individual would 
leave its impress upon growing feathers, it is not likely that it 
would, in the ease of a moulting bird, affect one phase or stage of 
feather growth without affecting all stages. 

Each feather has its own cycle of growth, and the supply and 
quality of the nutrition for the perfection of its different parts 
must vary with each stage of growth, independently of degree of 
blood-pressure dependent upon food-supply. Hence we should 
not like to say that ‘‘The formation of the quill is probably the 
direct result of a progressive diminution of an already lessened 
food-supply,’’ but that it was due to the normally modified 
supply and character of the nutriment furnished by the blood- 
vessels to the feather at this particular and final stage of its 

* Jones, Lynds. The Development of Nestling Feathers. Lab. Bull. 
No. 13, Oberlin College. Noticed in The Auk, January, 1907, p. 90. 


696 THE AMERICAN NATURALIST [Vou. XLII 


growth; or that the answer to Mr. Riddles’s question, ‘‘ What 
causes the production of ‘down’ 2’’ is to be found in malnutri- 
tion of the individual. A 


VERTEBRATE PALEONTOLOGY 


New Fossil Mammals from Egypt.—It was announced some time 
ago that the expedition of the American Museum of Natural 
History to the famous fossil beds of the Fayûm had been highly 
successful, and particulars of the results have been awaited with 
much interest. Professor Osborn has just issued a short paper! 
describing some of the more remarkable discoveries. Two new 
forms, unfortunately represented only by portions of the lower 
jaw, are so peculiar that their ordinal position remains uncer- 
tain. One of these is named Ptolemaia lyonsi, and is taken as 
the type of a new family Ptolemaiide. It is even stated that it 
possibly represents a new order. The other, Apidium phio- 
mensis, new genus and species, ‘‘was evidently a small omnivo- 
rous or frugivorous form with partly cuspidate teeth’’; but at 
present its precise affinities are unknown. Two other fossils are 
deseribed, representing new genera (Phiomys and Metaphiomys) 
of rodents, placed in the family Eomyide. 

TD AA 


Errata: The title of the article by Professor George H. Parker in the 
September issue, p. 601, should read ‘‘The Origin of the Lateral Eyes of 
Vertebrates.’’ The figure on p. 606 is inverted. 


* Bull. Am. Mus. N. Hist., XXIV, 265-272, March 25, 1908. 


(No. 501 was issued on September 30, 1908) 


The American Naturalist 


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AMERICAN NATURALIST 


VoL. XLII November, 1908 No. 503 


FURTHER STUDIES ON THE ACTIVITIES OF 
ARANEADS! 


PROFESSOR THOS. H. MONTGOMERY, JR. 
UNIVERSITY OF PENNSYLVANIA 


1. AGE DIFFERENCES IN THE SNARES OF TWO ARGIOPIDS 


To the best of my knowledge there has been made no 
comparison of the snares of immature and adult spiders, 
with regard to the problem of whether such snares be- 
come more complex as the animal grows older. Yet this 
is an interesting question in its bearings upon the per- 
fection of an activity through repeated effort. 

During the past months of July and August I have 
studied this matter on two common species of argiopids, 
Epeira sclopetaria (Clerck) and E. marmorea (Clerck), 
both of which construct large vertical, orbicular snares 
that are very favorable for measurements and the archi- 
tecture of which has been well described by McCook.? 

My observations were made at Woods Hole, Mass., 
where there was a large colony of sclopetaria in the labor- 
atory buildings and beneath the boat wharves, and an- 
other of marmorea in a marshy woodland. All the webs 
measured were those in the free and natural conditions, 
except those of the newly hatched; to obtain the latter I 
kept cocoons until they hatched, then freed the young 
upon the window panes of my room where they spun 
their first snares. Sclopetaria makes cocoons throughout 


' Contributions from the Zoological Laboratory of the University of 
Pennsylvania. 
° American Spiders and their Spinning Work, Philadelphia, 1889-93. 
697 


698 THE AMERICAN NATURALIST [Vou. XLII 


the summer, and one female under observation furnished 
four successive ones (all made in the night); they hatch 
on the twenty-fifth or twenty-sixth day. Marmorea does 
not construct cocoons until the fall. Comparisons were 
made on the following points: (1) number of radi, (2) 
number of spiral loops, (3) greatest diameter of the spiral 
(orb proper). The spiral loops examined are those of the 
outer viscid spiral which is the true trap of the web, and 
the number of its turns were counted in that segment 
of the orb where they*were most numerous (generally in 
the region below the central hub). A slight error is some- 
times encountered in counting these loops for occasionally 
the innermost of them are scarcely distinguishable from 
the inner non-viscid spiral, but this is an error of only 
small amount. 

The following table gives in condensed form the meas- 
urements of 265 snares. On the left is entered the spe- 
cies, sex and age, the linear measurements are in centi- 
meters, the remainder is self-explanatory. 


ETS Se ye RE E EN EE T ee eRe T A y, 


Spiral Loops Snare Diameter 


| Radii 
Sal ¢8 | ag a sf les ies| 8 A 
Ee) p4 | Sa |fe| £2 p23 28 |g 
o| tes of. S © betes} Nn 
59| dz |43 |59| dz |42 jee] a” |< 
2 9, ad 87 | 19-43 | 28.3 | 87 | 29-71 | 48.2 | 86 | 18.5-48.3| 28 ° 
29, catia Nasto instar | 19 | 21-35 | 27.8 | 19 | 16-61 | 48 |19 | 16.5-35.6 | 23.4 
aoe; seat titanic instar | 16 | 23-36 | 28.3 | 16 | 26-61 | 41.3/16/14 -30 | 20.6 
ed; antepenultimate 3, 19-34 | 27.38; 3) 37-39 | 38 3 ! 19.6-25.4 | 22.1 
Young es 6 an 23 | 19-35 | 28.7 | 23 | 16-51 | 29.5 | 21| 7.6-28 | 15 
E. sclopetaria : 
2 9, adult 24 | 15-24/19 |21 | 26-56 | 35.4 | 24 | 24.1-48.3 | 35.6 
, penultimate instar 2 | 18-23 | 20.5) 2): 4-30 | 27 2 | 20.3-30.5 | 25.4 
Newly hatche ao | 91 | 11-20 | 15.3 91 | 11-23 | 16.2|91| 5.1-11.9| 7.6 


With via to increase of complexity of the snare 
with advance of age of the spider this table shows us the 
following figures for sclopetaria. The first formed 
snares, those of the newly hatched, exhibit an average 
of 15.3 radii, 16.2 spiral turns and 7.6 em. diameter in 
comparison with averages of 19. radii, 35.4 spiral turns 


No. 503] THE ACTIVITIES OF ARANEADS 699 


and 35.6 em. diameter of adult females. In other words 
while the diameter of the orb increases nearly five times, 
the number of spirals becomes slightly more than doubled, 
and the number of radii are increased less than one quar- 
ter. For E. marmorea the webs of immature individuals 
of from .3 to .6 em. were compared with those of adult fe- 
males, and the table shows that between these ages the 
number of radii remains about constant, while the num- 
ber of spiral turns and the diameter of the spiral about 
double themselves ; females in the penultimate instar show 
the orb almost as complex as that of females in the last 
instar. For both of the species examined, accordingly, 
the age changes in the snare are greatest with regard to 
the diameter of the viscid spiral, less with regard to the 
number of its loops (on the average these only doubling 
their number), and least with regard to the number of the 
radii. 

It is interesting that the first snare of the spiderling 
has all the parts of that of the adult, namely, the central 
woven hub and the inner non-viscid spiral in addition to 
the viscid spiral, radii and foundation lines. With in- 
creasing age of the spider the threads of the snare become 
thicker, the whole structure larger, but otherwise beyond 
the addition of a few more radii and a doubling of the 
number of the spiral turns there is no particular change 
effected. The newly-hatched show also about the same 
specific habits as do the adult: in marmorea the young, 
as does the mother, remains in a nest in a curled leaf hold- 
ing communication with the snare only by a trap-line; 
and in sclopetaria the young, again like the mother, re- 
mains either at the center of the snare or else away from 
it, holding a trap-line but not hiding within a nest. Fur- 
ther, though there are frequently imperfections in the 
snares of the young, such as incomplete radii, asymmetri- 

3? By last or ultimate instar is meant the one of sexual maturity, even 
though this may be, and in some species regularly is, followed by other 
moults; the penultimate instar would be the next preceding, and the ante- 
penultimate the one before that. 


700 THE AMERICAN NATURALIST [ Vou. XLII 


cally placed spirals and imperfect meshing of the hub, 
such imperfections seem to be quite as usual in adult webs 
so that it is rare in either of these species to find per- 
fectly symmetrical webs. The adult spider can not be 
said to construct a more serviceable snare than does the 
spiderling, for the spiderling’s is really much larger in 
diameter in proportion to the size of the body. And while 
the adult has about twice as many spiral loops, the spider- 
ling with his fewer loops probably secures all necessary 
nourishment to the same extent as does his mother. Thus 
with the growth of the spider the snare does not become 
more serviceable as a trap. In all this excellent architec- 
ture the young as well as the adult labors first to make 
a scaffolding to support its weight, then lays down upon 
this the food-gathering spiral; and it does this quite as 
efficiently as does the adult. We might conclude that the 
number of spiral loops becomes larger because the supply 
of available silk has greatly increased; and that more 
radii are added because the weight of the spider increases 
faster than the size of the web, and because the spider 
in all her building tests the strength of the scaffolding, 
adding a new line wherever the structure sags. But the 
increase in number of parts can not be ascribed to intel- 
_ligence, or memory of reiterated experience, for the 
mother seems to continue the same instinct possessed by 
the young and shows no peculiarity in the spinning pro- 
cess not exhibited by the latter. The age differences of 
the web are, accordingly, due mainly to: (1) increase in 
the weight of the spider in combination with the instinct 
to make the scaffolding sufficiently strong; and increase 
of size of the spinning organs, therefore of silk substance. 
The spider does not exhibit learning at any stage, for it 
constructs the first web with as much ease and certainty 
as any later one. In this connection I may also mention, 
as the result of many observations, that the spider makes 
the first cocoon as perfectly as any subsequent cocoon; 
and when it makes a mistake at any part of the process 
of cocoon spinning seems unable to rectify it. 


No. 503] THE ACTIVITIES OF ARANEADS 701 


The absolute size of the snare and the number of spiral 
loops vary much in individuals of the same species. The 
Size is dependent upon two factors: (1) size of the space 
in which the web is spun, and (2) amount of silk avail- 
able. If confined in a cramped place the spider spins no 
snare at all, as I found by attempting to induce them to 
spin in cages made of two panes of window glass sep- 
arated by a wooden rim 3 em. thick. Then if successive 
webs are destroyed soon after making each contains fewer 
parts than its predecessor, which can be ascribed only to 
deficiency of silk. Thus with one adult female of 
sclopetaria her first snare had 21 radii, 35 spiral loops, 
and a diameter of 37 em.; this I destroyed, and her second 
made a day or two later had 17 radii, 25 spiral loops and 
a diameter of 30.5 em.; a week later I destroyed this and 
she made a third with 18 radii, 25 spiral loops and 
diameter of 24.1 em., then (after demolition of this one) 
a fourth with 19 radii, 19 spirals and diameter of 23 em. 

In orbs of adult females, particularly of marmorea, the 
space between neighboring spiral loops varies greatly 
in size, whence it follows that the diameter of the orb is 
no index of the number of spiral turnings, and that differ- 
ent females must use different parts of the body as a 
measure of this space. This is really the most marked 
variation to be found in orbs, and it is shown just as 
well in those of spiderings. 


2. THE Snares oF MALE Arcioprps AND THE NUMBER OF 
Mates 

In this conjunction I wished to compare the spinning 
activities of males of Epeira marmorea and E. sclopetaria 
with those of their females. On this matter McCook has 
to say :* 

As a rule, the spinning abilities of male spiders, as far as they relate 
to the capture of prey, have been shown in Volume I to be less decided 
than with females. The rule is not absolute for all species, as in 
some cases the snare spun by the male is precisely like that woven by 


“L c., 2, p. 65. 


702 THE AMERICAN NATURALIST [ Vou. XLII 


the female. But in certain other genera, as, for example, Argiope and 
probably Nephila, the snares of the male are rudimentary, and do 
not compare in perfection with those of the female. 

The immature males of the two species studied by 
me construct perfect snares of the types of those of 
their respective females. But the adult males of mar- 
morea (no adult males of sclopetaria were examined) do 
not spin snares at all but build nests near those of adult 
females and live on the outskirts of the snares of the 
latter; this was the case with all of the 23 mature males 
found in the latter half of the month of August. 

Data on the snares of immature males are condensed 
in the table already presented. The snares of orbs of 
16 males of marmorea in the penultimate instar show 
the same average number of radii, a somewhat smaller 
average number of spiral loops (41.3 to 48), and a 
smaller average diameter (20.6 cm. in comparison with 
23.4 cm. and 28. cm., as compared with snares of females 
of this species in the penultimate instar and at maturity. 
Data for the snares of 3 males in the antepenultimate 
instar show somewhat lower averages. Those of 2 males 
of sclopetaria in the penultimate instar, show, on com- 
parison with adult females of this species, a slightly 
greater average number of radii (20.5 to 19), a smaller 
average of spiral turns (27 to 35.4), and a smaller average 
diameter (25.4 em. to 35.6 em.). That is to say, males in 
their penultimate instar construct fully as many radii as 
do females in their penultimate or even ultimate instar, 
but a smaller number of spiral turns and they make 
smaller snares. But a male in his penultimate instar is 
considerably smaller than a female of the same age, there- 
fore in proportion to his size and weight his snare is quite 
as complicated as that of the female and is in no sense 
rudimentary. It would appear, accordingly, that the spin- 
ning instinct, so far as the snare is concerned, is as perfect 
in the male as in the female. He makes no web when ma- 
ture because the sexual impulse completely overcomes the 
desire for food, hence the instinct for snaring it, though 


‘an 


No. 503] THE ACTIVITIES OF ARANEADS 703 


he does continue to construct nests; and his nest is quite 
as complex as that of the female. I have not determined 
whether a male after satisfaction of his sexual desires 
would again spin a snare; but probably he would not 
have a chance of doing so, for the female becomes satisfied 
before he does and frequently succeeds in devouring him. 
Indeed, I have obsrved a female of marmorea devouring 
one male while another was importunely making advances 
to her. 

As to the sexual ratio of mormorea, I found in the 
field 16 males of the penultimate instar to 19 females of 
the same age, and 23 adult males to 87 adult females. 
These figures are too meager to allow of any general con- 
clusion, beyond that the males at maturity seem to be 
less than half as numerous as females, and just before ma- 
turity to be slightly less numerous. The greater disparity 
in numbers at maturity may well be due to accidents be- 
falling males while they are seeking mates and to their de- 
struction by the females themselves. On August 31 I 
measured the orbs of 24 adult females of marmorea; on 
only 8 of them were there adult males, these webs having 
from one to three males each. It is probable that more 
than one male copulates with a given female, and that a 
given male may mate with more than one female; for 
I have found this to be the case with Theridium tepidar- 
iorm and certain Lycosids.° 


3. Tue Senses oF ToucH AND SIGHT IN SNARE-MAKING 
PIDERS 

The number of eyes in araneads, usually eight, their 
different positions upon the head area, and their complex- 
ity in being compound (constructed of separate retin- 
ulae), has led naturalists to the view that the sense of 
sight plays a large part in their vital activities. And this 
idea is substantiated for such species as are strictly hunt- 

5 Before the antepenultimate instar males can not be distinguished ex- 
ternally from females. According to W. Wagner (La Mue des Araignées, 
Ann. Sci. Nat., 1888) the external male peculiarities do not exhibit them- 
selves in Attus before the fifth moult, and in Lycosa before the seventh. 


704 THE AMERICAN NATURALIST [ Vou. XLII 


ers and not snarers, and particularly for the diurnal At- 
tidae as demonstrated by the studies of the Peckhams.° 
But among the snare-weavers I feel positive, in agree- 
ment with McCook’s conclusions, that the sense of touch 
almost completely supplants that of sight. Long obser- 
vation in the field and especially upon species kept 
under control has led me to this opinion, the main rea- 
sons for which may be briefly mentioned. The lines of the 
snare are the medium by which the spider secures its food 
and conducts its mating, all by touch. In the operation of 
spinning, whether it be a snare or a nest or a cocoon, ° 
the process is conducted beneath the ventral surface 
of the spider, accordingly, in a position removed from 
its field of vision; and all such architecture is frequently 
carried on in the dark of night. With the true orb-weav- 
ers, the argiopids, the spider sometimes remains at the 
center of the orb holding tensely with its tarsal claws 
various radii and thereby feeling any object that strikes 
the web. In this position she can see only a small part 
of the snare, if any of it, yet she instantly perceives any 
impact upon any part of the snare. Or the spider does 
not rest upon the snare at all, or comes out upon it only 
at night and twilight, remaining in a nest at some dis- 
tance from the snare; in that case the spider perceives 
any shock to the snare by means of the trap-line that 
passes from her claws to the center of the snare, such a 
trap-line being a modified radius. MeCook (l. c.) has 
given an admirable treatment of the use of this trap-line 
and of how it is often employed to spring the snare. Thus 
Epeira marmorea remains through the hours of sunshine 
for the most part in a nest within a leaf that has curled 
up, where she can not see the web at all, and feels every 
motion of it through the connecting trap-line. And it is in- 
structive to watch her when an insect agitates the snare. 
She then rapidly pulls the trap-line several times, thereby 
learning that the prey is struggling in the web, runs 


* Peckham, G. W. and E. G. Sense of Sight in Spiders. Trans. 
Wisconsin Acad. Sci., 1894. 


No. 503] THE ACTIVITIES OF ARANEADS 705 


rapidly to the center of the snare, then locates the insect 
precisely by pulling successively different radii. In this 
food-gathering she seems to use touch alone, and it is 
questionable whether she at any time sees her food, for 
even in the process of mastication and sucking she holds 
it beneath her head. And this sense of touch is so deli- 
cate that by it the spider can to some extent determine the 
nature of the object that causes the impact, as, e. g., 
whether it be large or small. 

Likewise with the mating, that I observed this summer 
in Epeira marmorea. The female was near the center 
of her snare hanging vertically downward with her dorsal 
surface, her vision area, away from the male. He was 
at the outer end of one of her radii and though his 
head was turned towards her he perceived her position 
and tested her inclinations not by sight but by touch com- 
municated through that radius; they signalled to each 
other by pulls and counter pulls of the line, he climbed 
along the radius towards her, at nearly every step re- 
peating his pulling, then when about an inch away he 
advanced rapidly to press his palpi against her epigynum 
while she drew in her extremities close to her body. Each 
such act was only of momentary duration, and at its 
end he moved away along the same radius, repeated his 
signalling, then again advanced towards her; thus there 
were numerous repeated copulations during the half hour 
I watched the pair.” The female never saw the male at 
all, and he perceived her so far as I could determine by 
the sense of touch alone. In an earlier study, where I 

T Previous observers of European a of this genus have described 
this process in much the same w mpare: 

alckenaer. Histoire naturelle des Tuet, Aptères. Suites à Buffon, 
2, Paris, 1837. 
Menge, A. Ueber die Lebensweise der Arachniden. Schriften naturf. 
Ges. Danzig, 4, 1843. 
Menge. Preussische Spinnen, I. Ibid. (N. F.), 1, 1866. 
Termeyer, R. M. de. Researches and Experiments upon Silk from 
mon ete. Translated by Burt G. Wilder, Proc. Essex Inst., 5, 1866. 
, A. Ueber die Begattung der gekrénten Taino (Epeira 
POEA Cl.). Termész. Fuzetek, Budapest, 10, 1886. 
+ 


706 THE AMERICAN NATURALIST [Vor. XLII 


described this act in much greater detail for various 
other species,’ I had called attention to this exclusive 
use of touch in the courtship and copulation of snare- 
weavers. The female responds to the male’s signals by 
more gentle and weak pulls when she is eager for him, 
by stronger and more aggressive ones when she regards 
him as an object of food; thus there is a language of 
touch, even at a distance, and the male assures himself, 
if such an expression is permissible, of the nature of his 
partner’s responses. In the case of marmorea just de- 
scribed the male took effective means to procure his es- 
cape should the female prove aggressive, just as did 
the male of E. diademata observed by Menge: while 
advancing along her web radius he held an escape line of 
his own, the outer end of which was attached to the peri- 
phery of her web; and when her motions were more vio- 
lent than usual he loosed his hold on her radius to drop 
and swing out of her reach on his own escape line. In 
this way he procured the double advantage of escape and 
of remaining in communication with her web. 

It may be noted in passing that while in E. marmorea 
the male seeks only adult females, in Theridium tepidar- 
iorum the males mature somewhat earlier than the fe- 
males and are to be found upon the webs of the females 
before the latter have matured. 

We can say that among araneads the sense of touch 
is the dominant one in those that are snarers. Spiders 
lack hearing, as seems to be proved by the experiments 
of my student Miss Pritchett.2 The long spines placed 
upon the limbs seem to be tactile and not auditory or- 
gans. Spiders possess the olfactory sense but it is not 
known how much they are guided by it. The primary 
sense of the snarers is touch, and they possess it to a 

*Studies on the Habits of Spiders, particularly those of the Mating 
Period, Proc. Acad. Nat. Sci. Philadelphia, 1903. 

* Pritehett, A. H. Observations on Hearing and Smell in Spiders. 
AMER. NAT., 38, 1904. These observations have been criticized by F. Dahl 


(Naturwiss. Wochenschr., N. F., 4, 1905), but Dahl never instituted crucial 
experiments such as those of Miss Pritchett. 


No. 503] THE ACTIVITIES OF ARANEADS TOT 


degree of perfection hardly equalled by any other ter- 
restrial animals. 

The question then presses, of what use are the eyes to 
snare-weavers when their sensations are so particularly 
tactile? The newly hatched spiderlings evidently use 
their eyes for they are always positively phototropic while 
the adults are generally negatively so. This turning to- 
wards the light benefits the spiderlings and consequently 
the species by serving to disseminate them from the home 
area into new feeding grounds. And I believe it is a 
quite general phenomenon among all animals whose adults 
are more or less sedentary and tubicolous, negatively pho- 
totropic, for the young to be at first positively phototropic, 
though I do not know whether any one has drawn atten- 
tion to the comprehensiveness of this principle; in this 
most wide-spread kind of migration the beneficial result 
of the change of tropism is to prevent overcrowding. 
But as the young snare-weaver grows older and begins 
to avoid the light as does its parent, it does not employ 
its eyes in the primal acts of feeding and mating but main- 
ly determines by them the source of the light in order to 
avoid it. Despite their complexity, accordingly, the eyes 
of snare-weavers, when they have passed infancy, seem to 
. be used mostly as direction eyes. This being the case it 
seems strange that these eyes should have retained the 
complexity inherited from hunting forefathers, and it is 
possible that they have come to subserve some other new 
function, as, e. g., to have become thermic receptors; 
this might well be determined experimentally. At any 
rate we shall have to change current views as to the réle 
of vision in spiders. 


4. On THE AverRAGE Duration oF LIFE IN ARANEADS 

In the ease of all species that I have studied adult 
males are found during only a short period of the year, 
for perhaps not longer than a month or six weeks, and 
in latitudes where there is a marked winter season they 
do not live over this period of cold. And from observa- 
tions on Theridium tepidariorum I estimate from the rate 


708 THE AMERICAN NATURALIST [ Vou. XLII 


of growth that this species is able to reach full size in 
one year. Males, accordingly, live for only a relatively 
short time as adults, and their life time would seem to not 
exceed one year. In my observations on Epeira mar- 
morea I found on July 25 among 16 recognizable females 
(in young of 8 mm. body length or less the sexes are ex- 
ternally indistinguishable) only 5 adults, while on August 
31 out of 24 females all but 3 were adult; these data indi- 
cate for this species that while at the beginning of the 
summer few females are adults, at its end most are. It 
is then probable for this species, though not proved, that 
few females live over from one breeding season to another, 
and then only under favoring environmental conditions, 
a conclusion reached by McCook for Argiope. But the 
females live at least some months longer than the males 
for they are to be found later than the breeding season 
and after all males have disappeared; and there are cases 
on record (cf. McCook) where females of certain species 
have been kept from two to seven years. I have de- 
scribed for Latrodectus'® how the mating occurs in the 
late winter at Austin, Texas, the adult males are not 
found after this season, while the females continue to 
produce cocoons until the following autumn. We might 
say in general that males of spiders probably do not live 
longer than one year, females some months longer or 
in certain cases several years. 


5. THE Cocoontne OF LOXOSCELES RUFESCENS DUF 

I give these brief notes here because the cocooning of 
no sicariid has been hitherto described, and because it 
may be of some interest from the standpoint of com- 
parative architecture. The cocoon of Loxosceles is ses- 
sile, attached to the snare, so resembling that of Sicarius, 
while in Scytodes, the only other genus of the Sicariidae 
for which the cocoon has been described, it is carried in 
the chelicera of the mother.” 

1 Jour. Exper. Zool., 5, 1908. 


“I have taken thene genera as defined by E. Simon: Histoire naturelle 
-~ des Araignées, 2me éd., Paris, 1892. 


No. 503] THE ACTIVITIES OF ARANEADS 709 


This is an abundant form at Austin, Texas, where it 
makes a large and irregular web beneath logs and stones, 
usually in drier situations. In its movements it is the 
most languid and timid species I have ever seen, waiting 
quietly until its prey has inextricably entangled itself in 
the web, and feigning death for a remarkably long period. 
Both males and females are able to undergo thirst for 
weeks at a time, an unusual faculty among spiders, and 
to this ability it probably owes its success under the desic- 
eating Texan sun. 

On June 13, 1907, I placed six females in separate glass 
cages. Four of them when first found had each a single 
cocoon, and each produced cocoons in captivity to the 
number of from two to four each. One of them produced 
five cocoons in all.12 The season of cocooning evidently 
extends through the whole three months of the summer. 

The cocoons are discoidal, with diameter longer than 
the spider’s body, and are made in the mornings from 
seven o’clock to noon. In the two cases where the opera- _ 
tion was observed they were spun against a vertical wall 
of the cage, not placed horizontally. After making the 
base, a process not seen, the spider remains quietly above 
it until the following day, a cessation of activity quite 
unique among araneads but thoroughly in accord with 
Loxosceles’s quiet disposition. Then the eggs are laid 
upon this base, an act that occupied eight minutes in the 
case where it was followed. Over the egg mass the 
mother spins a thin-textured cover, swaying the spinner- 
ets leisurely back and forth; this cover spinning occupied 
one hour in the case where it was timed. The mother 
remains upon the cocoon until it hatches. 

2 Some naturalists write as though multiple cocoons were a rather ex- 
ceptional phenomenon among spiders. On the contrary I believe it is the 
general if not universal rule, for I have found it to be the case also in 
lyeosids, pisaurids, attids, agalenids, thomisids, clubionids, drassids, ther- 
idiids, argiopids, dictyniids and filistatids. 


NOTES ON THE DAILY LIFE AND FOOD OF 
CAMBARUS BARTONIUS BARTON? 


FLOYD E. CHIDESTER 


In all animals we find that there are periods of ac- 
tivity and rest. During the active period, we find such 
interesting phenomena as feeding, copulation, and, in some 
animals, a very interesting series of movements connected 
with the care of the young. 

My study of the daily life of the crawfish is one of a 
series of studies instigated by Professor C. F. Hodge in 
the effort to arrive at some accurate data as to the work 
performed by various species. 

Crawfish were kept in two different aquaria during the 
winter of 1907-’08, and their actions watched closely. 

One tank was an ordinary running water tank with 
a pile of sand at one end, and containing, in addition to 
crawfish, at times, trout eggs, young trout, frogs, clams 
and a turtle. There were also, all the time the crawfish 
were kept there, several tufts of the common water weed, 
Fontinalis, floating in the water. 

The other tank was a heavy glass aquarium, measuring 
on the inside, 1x1$x2 feet 8 in. This aquarium was 
elevated about an inch at one end, and beginning at the 
other end, a mud and sand bottom sloped gradually up- 
ward to a level bank which was covered with moss and 
grass and kept moist 

In the aquarium was a clam to assist in clearing the 
water, a water hyacinth, and some more of the water weed 
mentioned above. 

At different times, as I experimented with the food of . 
the crawfish, there were bits of fresh meat, sprouts, eggs 
and young of trout, toads, frogs and salamanders; dead 
frogs and fish, and dead crawfish. 


_* Contributions from the Biological Laboratory, Clark University. 
710 


No. 503] CAMBARUS BARTONIUS BARTONI 711 


The water was changed daily and oftener at feeding 
time, during the entire winter, and record kept of the 
activities of the crawfish. It was not until spring, how- 
ever, that night and day observations were made. 

During the fall and winter, up to February 1, frequent 
cases of copulation were observed. Contrary to Dear- 
born’s statement, ’00, I found that the males do not know 
the females and that males repeatedly grasp other males, 
and sometimes, in spite of their frantic struggles, turn 
them over and attempt to copulate with them. The dif- 
ference in behavior in the case of the male, when thus 
grasped, is that he continues to resist violently at inter- 
vals, until released, while the female, as soon as grasped 
firmly, ceases to struggle, and lies passive. 

Another interesting thing was noted in connection with 
the actions of crawfish before moulting. In the case of 
adult crawfish with hard exo-skeletons, I found that for 
two or three days before the eedysis, they would come up 
partly out of the water, so that the carapace was entirely 
out of the water, and dried out thoroughly. 

Crawfish when transferred from the running water 
tank to the still water one, would almost immediately seek 
cover, generally burrowing into the bank, and remaining 
during the day with their heads toward the entrance, quiet 
unless disturbed. 

In the still water aquarium, there were at one time, six 
crawfish hibernating in the bank, with their burrows 
stopped up, for three weeks. The other seven in this tank 
were in the deep water under plants during the day, but, 
as darkness fell, they came up into the shallows and on 
the bank. 

Repeatedly, I have come into the building after dark- 
ness had set in, and seldom failed to find several crawfish 
on the bank. 

Crawfish are generally supposed to be omnivorous. 
They are not, however, so fond of decayed matter as has 
been supposed. Tests made in the laboratory show that, 
when they refuse to eat stale food, they will eagerly con- 


712 THE AMERICAN NATURALIST [ Vou. XLII 


sume fresh. They will eat fish which have been recently 
killed, in preference to partly decayed ones. 

In the spring, after moulting, there seems to be a con- 
suming hunger. I have seen, at about 9 P. M., a craw- 
fish within about six inches of the bank of a small pond, 
so intent on pulling to pieces and devouring a partly de- 
eayed fish, that he did not-notice the very strong 
acetylene light that I held close to him. 

Experiments with lights of various intensities, eluci- 
dated the fact that crawfish are negatively phototactic to 
strong light but positively phototactic to weak light. 

Raw and cooked meat of all kinds, worms, dead fish, 
pieces of clam, moulting crawfish, and dead crawfish were 
eaten by the crawfish in confinement. They are said to 
eat their own cast-off coats, but although these were left in 
the aquarium for about a month, they were undisturbed. 

Tests were made to determine if the crawfish would 
eat fish (trout), frog and toad eggs. Very few were 
eaten, and these few when the crawfish had had nothing 
to eat for ten days, and had nothing else to eat. 

Young frog and toad tadpoles were kept in the aquaria 
and lived happily for a long time.. To determine if craw- 
fish eat toad or frog tadpoles, twenty-five toad and frog 
tadpoles were placed in a shallow dish, and, with a re- 
newal of water every day, kept for four days with a 
single, supposedly hungry, crawfish. Of the twenty-five 
tadpoles, in all, but eight were eaten. 

About two weeks later, when the tadpoles had become 
quite a little larger, a test was made with toad tadpoles. 
A male crawfish was placed in a shallow aquarium jar 
with twelve live tadpoles, and kept for three days, with 
change of water twice a day. It was not until about fifty 
hours had elapsed that he ate of the tadpoles, and then 
he ate but one. 

A female crawfish was put into an aquarium jar at the 
same time as the male, with 12 live toad tadpoles. This 
was at 5 P. M. At 6 P. M., she had eaten all but one of 
them. At 6 P. M., 17 more were put in, making 18 in all. 


No. 503] CAMBARUS BARTONIUS BARTONI 713 


At 10:30 P. M., five more tadpoles were gone. At 9 
A. M., on Friday, only 5 were left, one of these being 
dead. This was a record of 22 out of 27 active tadpoles 
in 16 hours. The female was seen to catch several of the 
tadpoles, using for this, not her cumbersome chelæ, but 
her smaller, nimble, first pair of ambulatory appendages. 

Evidently Cambarus bartonius bartoni is capable of 
catching toad tadpoles, but it is improbable that many 
are caught, for I am informed by Mr. Newton Miller that 
the young tadpoles, although near the shore during, the 
day, go to the deeper water at night. It is at night that 
the crawfish come into the shallower water near the shore, 
and even part way out of the water. Here it is that they 
may catch an occasional fish, frog or toad. 

Two young frogs were kept during the greater part 
of the winter in one of the aquaria on my desk with the 
crawfish, but none of the dozen seemed able to kill them. 
Once I forced a frog to swim down to one corner of the 
tank where several crawfish were collected, and one of the 
crawfish grasped a hind leg with his right chela, and a 
moment later secured the front leg on the same side with 
his left chela. He then forced the frog to the bottom 
and attempted to pull him limb from limb, all the time 
holding the animal under water. In just a moment, how- 
ever, the frog kicked with his free hind leg, and accident- 
ally striking the crawfish on the carapace, was released. 

My observations and experiments in the laboratory were 
supplemented by many evenings spent on the shores of 
several small ponds near the university, observations be- 
ing made by means of a strong acetylene light. I believe, 
in the light of these observations, that the crawfish in the 
still water aquarium behaved normally. 

In the spring, the crawfish is very active, and feeds 
with much more eagerness than during the winter. It 
is then, too, that the interesting phase of the mother’s care 
of the eggs may be best seen. 

On account of this, I took occasion to watch a pair of 
crawfish, a male, and a female with eggs just about ready 


714 THE AMERICAN NATURALIST [ Vou. XLII 


to hatch, through 24 consecutive hours, beside several ob- 
servations of lesser duration. 

In these observations, I was aided by Dr. C. F. Hodge 
and Mr. Newton Miller, who kindly gave me occasional 
resting periods. 

The first set of observations which I shall record were 
made on May 16-17, 1908. 

Observation was begun at 6 P. M. on two crawfish, a 
male and a female with eggs about ready to hatch, and 
lasted until 6 A. M. the following day. In the aquarium 
with the crawfish, were the water hyacinth and Fontinalis 
mentioned above, some young sprouts, five young toad 
tadpoles, and some pieces of fresh meat. 

The male was moderately active between 8.10 and 8.45 
P. M., most active between 12. and 1.30 A. M., and had 
a lesser period of activity between 2.05 and 2.30 A. M. 
The longest period of quietude was from 1.30 to 2.10 
A. M. He ascended and descended the bank nine times 
during the 12 hours. The male did not feed. 

The female ascended and descended the bank 84 times 
during the 12 hours. She ascended and descended 17 
times between 1 and 2 A. M. She would climb the bank 
and aerate her eggs in the open for several moments, then 
retire to the deep water and almost immediately return to 
the bank. The greatest activity was from 11 P. M. to 6 A. 
M. She fed at 6.50 and again at 7.07 P. M. both times on 
the fresh meat. Her longest rest period was from 10.30 to 
to 11 P. M. 

The next series of observations was performed on three 
crawfish, the two observed on May 16-17, and in addition, 
a female without eggs. This time observation was kept 
up for 24 consecutive hours, from 1 P. M. May 19, to 1 P. 
M. May 20 

The same kind of food was used as before, care being 
taken to avoid fouling the water with it until about one- 
half hour before the records were taken. 

_ The male fed a great deal this time on the fresh meat, 
feeding from 1.35-2.15 P. M., 2.30-245 P. M., 3.18-3.40 P. 


No. 503] CAMBARUS BARTONIUS BARTONI 715 


M., 3.48-5.00 P. M., 4.10-4.30 P. M. 

He was most active from 11.35. P. M. to 3.15. A. M. 
It is interesting to note that each period of feeding, if 
lengthy, was followed by a correspondingly long period of 
rest. The longest rest period was from 4.45 to 8.05 A. 
M. The male did not ascend the bank at all during the 
24 hours. 

The female with eggs began ascending the bank and 
aerating her eggs at 4 A. M. and stopped at about 4.25 
A. M., then began again at 6.15 A. M. gradually length- 
ening the stay on the bank until 9 A. M. then shortening 
the frequency of the visits, and lengthening the stay in 
the water; this period of less frequent visits lasted until 
11 A. M., then from 11 A. M. to 12 M., there was great 
regularity of aeration, and from 12 M. to 1 P. M., less 
frequent aeration. Ascent of the bank was made thirty- 
four times during the 24 hours. 

Feeding was done at 1:45 P. M., and again at 2.15 P. M., 
but in neither case did it last longer than ten minutes. 

Number seven, a female without eggs, was very inactive, 
staying under a stone the greater part of the time. She 
came out on the bank but three times. Her period of 
greatest activity was between 3.30 and 4.15 P. M. 

From these observations of the crawfish in nature and 
in the laboratory, we may conclude as follows: 

1. Crawfish are most active at night. 

2. There is marked activity at nightfall and at daybreak. 

5. Feeding is generally done at night, but may occur 
during the day. 

4. In the spring, the crawfish eats much more often 
than during the winter. 

5. Cambarus bartonius bartoni prefers fresh animal 
food to anything else. 

6. Feeding is followed by rest, prolonged periods of 
feeding being followed by equally prolonged periods of 
rest, the animal not becoming active for several hours. 

7. There is apparently no spontaneous play or exercise, 
movements being purely utilitarian. 


716 THE AMERICAN NATURALIST [ Vou. XLII 


8. A female aerates her eggs both on land and in water. 

9. Crawfish come up into the shallows and elevate their 
carapaces partly out of the water. 

10. Combing or cleaning movements are executed by 
means of the first and second ambulatory appendages. 
These consist in scraping the carapace. 

11. Males do not distinguish between the other males 
and the females, and frequently grasp males and attempt 
to copulate with them. 


LITERATURE 

1895. Andrews, E. A. Conjugation in an American Crayfish. Am. Nat., 
Vol. 29, pp. 867-875. 

1900. Dearborn, G. N. Notes on the individual psycho-physiology of the 
crayfish. Am. J. Physiol., Vol. 3, pp. 404-433 

1895. Herrick, F. H. The American Lobster. Bull. U. S. Fish Com- 
mission, 1895, pp. 1-25 

Ortmann, A. E. The Ciawian of the State of ae 

Monies of the Carnegie Museum, Pittsburgh, Pa. Vo 
No. 10, pp. 343-523. 


SOME POINTS IN THE ECOLOGY OF RECENT 
CRINOIDS 


AUSTIN HOBART CLARK 


ALTHOUGH a considerable amount of work has been 
done on the anatomy of various species of recent crinoids, 
the embryology and development of two species, closely 
allied, are well understood, and the systematic side of 
the question has received more or less attention, little has 
been accomplished in the elucidation of the interrelation 
of the crinoids and the other classes of marine inverte- 
brates, or the relation of the crinoids to marine conditions 
in general. This is undoubtedly due to the rarity of the 
group, and its chiefly inaccessible habitat, rendering it, 
as a whole, a difficult subject for extensive research; but 
much may be learned from the data already recorded, and 
it is the purpose of the present paper to suggest certain 
lines along which much of interest may be done on the 
basis of the present numerous, though scattered, records. 

It has long been known in regard to Antedon bifida of 
the coasts of Europe that specimens taken in deep water 
are larger than those taken in shallow water or along the 
shore, though no plausible reason has been shown for 
the phenomenon. It has been suggested that the coldness 
of the deeper water may stimulate it to greater develop- 
ment; but specimens from different localities, taken at a 
considerable difference in depth, yet with the same bot- 
tom temperature, will vary greatly, those from the greater 
depth being much the larger; similarly, specimens from 
the same depth, but with marked difference in the bottom 
temperature, will be found to be of practically the same 
size. As, however, specimens from very shallow water 
are usually about 120 mm. in expanse, while those from 
deep water are 220 mm. or more, it is evident that some 
important factor is involved. 

717 


718 THE AMERICAN NATURALIST [ Von. XLII 


The food of crinoids consists of very small pelagic 
organisms and minute crustacea. At or near the surface 
the crinoid must depend upon those which swim within 
reach of its pinnules or which it may intercept by the 
slow movement of its arms; but in deeper water while 
this source of supply is just as available as at the surface, 
the crinoid gets, in addition, all the carcasses of those 
organisms in the levels above it which die and are pre- 
cipitated to the bottom. The intensity of this rain of 
food increases proportionately with the depth, so that 
the deeper a crinoid lives, the greater is the available food 
supply; consequently, the better nourished will be the 
individual and the greater its size. 

We see, therefore, that the size of Antedon bifida ap- 
pears to be merely a question of food supply. Passing 
from a single species to a consideration of the group in 
general, we find that the average size gradually increases 
from the shore line to about the 100 fathom mark; this 
is plainly due to the gradual increase in the supply of 
food, as just explained; from 100 fathoms to about 600 
fathoms the same size is maintained; but below 100 
fathoms plant life, and with it the host of small organisms 
dependent directly or indirectly upon it, upon which (as 
well as upon certain of the minute plants) crinoids are 
dependent for food, begins to disappear. This gradual 
disappearance of vegetable organisms and their de- 
pendents is offset by the gradual increase in the rain of 
carcasses from above, so that an equilibrium is maintained 
down to about 600 fathoms, and hence the size of the 
crinoids remains about the same from the 100 to the 600 
fathom mark. Below 600 fathoms, the gradual decom- 
position of the rain of carcasses progressively lessens its 
food value, and, therefore, we note a decrease in the size 
of the crinoids, hardly noticeable at first, but soon be- 
coming more marked, until, below 2,000 fathoms, we find 
only the minute comatulid Bathymetra and the equally | 
minute stalked Bathycrinus. 

_ By this hypothesis the general absence of the Pen- 


No. 503] ECOLOGY OF RECENT CRINOIDS 719 


tacrinitide above 100 fathoms is at once explained; the 
stalked pentacrinites (Enerinus, Endoxocrinus and 
Hypalocrinus) are animals of very considerable size; 
besides a large crown they have a bulky stem which must 
be nourished, and the organisms found at or near the 
surface are not sufficient to support them; it is not until 
the depth of approximately 100 fathoms is reached that 
the organisms occurring in the water about them, plus the 
cumulative effect of the rain of dead from a belt 100 
fathoms in depth, acquires sufficient intensity to admit of 
their existence. Incidentally, their remarkable uni- 
formity in size is explained; for the recent pentacrinites 
inhabit almost exclusively the 100-600 fathom belt, which 
has just been shown to be a belt of uniform crinoid size. 
A species of Endoxocrinus, E. wyville-thomsont, and the 
peculiar Hypalocrinus both descend to over 1,000 fathoms, 
but both are much smaller than their relatives above the 
600 fathom line. 

The common arctice comatulid, Heliometra glacialis 
(= eschrichtii) occurs from east of the Kara Sea to west- 
ward of Greenland, thence southward to off Nova Scotia ;! 
the southern part of the Sea of Okhotsk and the northern 
part of the Sea of Japan are inhabited by a variety, 
maxima, differing only in its great size. This species 
varies greatly throughout its wide range; north of 
Europe it is small, though rather larger around Spitz- 
bergen; off Halifax and on the Grand Banks it reaches a 
comparatively large size, while off the western coast of 
Greenland it attains a diameter of 500 mm. or more, 
reaching 700 mm. in the Okhotsk and Japan Seas. 

The west coast of Greenland abounds in fjords which 
are continually giving off fresh water ice which floats 
away, melting as it goes, thereby killing millions of small 
organisms which are unable to endure a great change in 
the salinity of the medium they inhabit; these fall to the 
bottom and furnish an abundant supply of food for the 


*Stimpson’s Alecto eschrichtii from Grand Manan is in reality Hath- 
rometra tenella. . 


720 THE AMERICAN NATURALIST [ Vou. XLII 


-erinoids there, which consequently are enabled to attain 
very considerable dimensions. In the Kara and Barents 
Seas there is no such supply of fresh water at hand, hence 
the crinoids are small, but Spitzbergen, through its snow 
fields, and the consequent freshening of the surface water 
about it, allows the crinoids along its shores to reach a 
larger size than those of the Barents and Kara Seas, 
though they are not nearly so large as are those from 
west Greenland. 

Over the Grand Banks the Gulf Stream brushes by, and 
mixes more or less with, the cold northern current; this 
is fatal to the delicate southern life it contains, which is 
killed and precipitated to the crinoids below; they, there- 
fore, in spite of their living on the extreme southern limit 
of the specific range, are as large as, or larger than, speci- 
mens from Spitzbergen. 

The Kuro Shiwo, or Japanese current, sends off a 
branch through the Korean Straits which washes the 
eastern shore of the Japan Sea, and in its northern part, 
from the Straits of Tsugaru to the Straits of La Pérouse 
mingles with the very cold water from the Okhotsk Sea. 
The mixing is very gradual and extends over a consider- 
able territory, and over all this area the crinoids are of 
gigantic size, bearing witness to their enormous food 
supply. Now this colony of Heliometra glacialis var. 
maxima, a purely arctic species, replaced on the Pacific 
side of Japan and the Kuril Islands by widely different 
forms, and finding no close relatives nearer than the 
Kara Sea, might be supposed in the course of the years 
which have elapsed since the Okhotsk Sea was part of 
the Arctic Ocean, to have become rather widely differen- 
tiated from the parent stock, and to have gradually 
reached a larger adult size from some other cause than 
the question of food supply; fortunately, however, we are 
able to make some observations bearing directly upon 
this point. In this area, Heliometra is found where the 
bottom temperature is very low, about freezing or less; 
but dovetailed into these cold areas are others where the 


No. 503] ECOLOGY OF RECENT CRINOIDS 721 


bottom temperature is 40° F. or above. These warmer 
areas are occupied by a fauna radically distinct from. the 
arctic fauna of the cold areas, though the depth is about 
the same, and we find in them crinoids belonging to the 
purely Pacific genera Thaumatometra and Psathyrometra. 
It is gratifying to note that the representatives of both 
these genera are far larger here than anywhere else, the 
difference, in fact, being relatively greater than in the case 
of Heliometra. These three genera here live among en- 
tirely different surroundings, and in widely different 
temperatures; but their food supply, coming in a rain 
from above, is the same, and is, moreover, the only com- 
mon ecological factor; therefore, there is no room for 
doubt that the food supply is the cause of the great in- 
crease in size. 

While the recent pentacrinites as a rule live below 100 
fathoms, in certain places, such as in some localities 
along the northern coasts of Cuba and Guadeloupe, and 
in Suruga Gulf and Sagami Bay, Japan, they approach 
much nearer the surface, and have even been taken in 
water of between 20 and 30 fathoms (Guadeloupe). Now 
Cuba and Guadeloupe are mountainous islands, while 
Suruga Gulf and Sagami Bay are close to that magnifi- 
cent mountain Fuji-Yama, and to other high lands as 
well. The result is that many intermittent streams flow 
into the sea at these places, having their origin in the high 
lands; the rise in volume of their waters is so sudden - 
that the pelagic life can not give way before it, but is 
killed and precipitated. The greatly increased food sup- 
ply in the vicinity of one of these streams thus brings the 
food intensity up to such a level that the large pen- 
tacrinites may exist in such localities in much shallower 
water than would otherwise be possible. The water from 
these streams is never very great in amount, and does 
not penetrate deeply, but spreads out over the surface of 
the sea; thus a crinoid could exist very near the surface 
without being affected by it. Large rivers with a com- 
paratively steady flow, on the other hand, freshen the 


722 THE AMERICAN NATURALIST [ Vou. XLII 


entire sea for a large distance from their mouths, and 
thus render crinoid life impossible. 

Within the tropics, particularly in the Hast Indies, 
very large comatulids belonging to the Tropiometrida, the 
Zygometride, the Himerometride, and the Comasteride 
occur abundantly in very shallow water, often just below 
the low tide mark; moreover, they decrease in size with 
depth. This would appear to directly contradict the 
conclusion reached in the case of Antedon bifida, but in 
reality the problem is an entirely different one. Within 
the tropics the intense scorching sunlight causes rapid 
evaporation from the surface of the sea, especially where 
the water is shallow, and a consequent mortality among 
the more delicate organisms. The beaches and rocky 
shores, at low tide, warm up, to be covered again at high 
tide with comparatively cool water, full of organisms 
unable to stand a great difference in temperature, which 
are consequently killed and swept back into the sea, to 
fall just beyond the low tide mark. Periods of glaring 
sunshine are relieved by torrential rains, which are just 
as fatal to pelagic life through the sudden lowering in 
the density of the surface water. Thus it is evident that 
within the tropics the sublittoral zone and the sea bottom 
near the shore line offer the maximum food supply for 
the crinoids, and explain the occurrence in such localities 
of members of these four families of very large size. 

But torrential rains are associated with mountainous 
districts; a glance at the distribution of the species of 
these four families shows that all of the large species and 
practically all of the small ones occur exclusively about 
mountainous islands or near high mainland, and they are 
particularly abundant along the shores of the larger East 
Indian Islands. On isolated coral reefs and about the 
shores of low coral islands where, owing to the very low 
altitude of what little land there is the rainfall is very 
small, these large littoral erinoids are quite absent. 

The comatulids are divided into two great groups, one 
with triangular pinnules and small eggs, the Thalas- 


No. 503] ECOLOGY OF RECENT CRINOIDS 123 


sometroida, the other with round pinnules and large eggs, 
the Antedonoida. The forms with small eggs, being no 
smaller than those with large eggs, may reasonably be 
supposed to require a longer period for development. 
This would imply a greater duration of the free swim- 
ming larval period, which would result in greater powers 
of dispersal, hence a greater geographic range. More- 
over, a slowly developing larva might be supposed to 
possess a greater power of adaptation to environment, 
and therefore a certain ability to colonize new places un- 
der changed conditions, for instance, to spread down- 
ward to great depths. 

The genus Thalassometra, genus of the Thalas- 
sometroida (with small eggs) has the widest distribution 
of any comatulid genus known, geographically and 
bathymetriecally. It is found throughout the tropics, 
northward to the Aleutian Islands, the West Indies and 
Portugal, and southward to South Africa, the Crozet 
Islands and Australia; in depth it ranges from about 
50 to 1,600 fathoms. Charitometra and Tropiometra, 
two other genera of the same group, are both inter- 
tropical, and the former reaches very considerable depths. 
The genera belonging to the Antedonoida (with large 
eggs) are mainly comparatively local and do not.occupy 
large bathymetric altitudes. Though a number are 
littoral and one inhabits the greatest depths from which 
erinoids are now known, the bathymetric range of each 
is small, far smaller than that of the genera of Thalas- 
sometroida. 

The beautiful and brilliant coloration of the crinoids 
has often been remarked; so striking is the common Euro- 
pean species, Antedon bifida, that it has formed the sub- 
ject of colored plates by Heusinger, Dujardin, Dalyell, 
Dujardin and Hupé, and Gosse; but the larger tropical 
species are much more varied and handsome (though 
colored figures of them have been published only by 
Leach, and by Kuhl and van Hasselt) and are, for the 
diversity of their markings and the delicacy of their hues 


724 THE AMERICAN NATURALIST [ Vou. XLII 


unrivaled among the marine invertebrates. Observers 
have contented themselves with making short color notes, 
each on a very limited number of species, and no one has 
as yet made this phase of the subject an object of study, 
yet there appear to be many interesting points well 
worthy of record. 

All colors are found in the crinoids except blue, though 
true black is confined to the disks of the Pentametro- 
crinide and to lines and spots on two species of Cocco- 
metra, and may therefore be omitted from a general dis- 
cussion. Both blue and black, however, enter largely 
into combinations. 

Yellow is the commonest color in the group, and is the 
color of all the more primitive forms, and of the young 
of almost all the others; it may, therefore, be taken as 
the fundamental basic crinoid color. The pentacrinoids 
of Antedon bifida are sometimes pink, though usually, 
like the pentacrinoids of the other forms in which they 
are known, yellow, and certain other forms are dull pinkish 
at all stages. We may, therefore, assume two basic colors, 
yellow and red, the latter an intensification of the former, 
found generally in the more specialized forms. 

The derivatives from these two basic colors as they 
occur in the crinoids may be grouped as follows: 


White. 
I. Yellow J + [Blue] = | Green. 
+ [Black] = Brown. 
Purple; maroon. 
II. Red j Tem = tida 
+ [Black] = Crimson. 


Under the first heading come: 

Yellow: Bathycrinus, Rhizocrinus, Ptilocrinus, Phryno- 
crinus, Nanometra, Adelometra, Trichometra, Heliometra, 
Atelecrinus, and all but very large specimens of the 
species of Thalassometridæ. 

White: Asterometra; markings on shallow water 
Thalassometridæ. 


Green: Hathrometra, Coccometra, Leptometra, Comp- 
sometra. : 


No. 503] ECOLOGY OF RECENT CRINOIDS 725 


Brown: Very large specimens of all the species of 
Thalassometride, Thaumatometra, and Thysanometra. 

Under the second heading come, Zenometra, Psathyro- 
metra, Bathymetra, Isometra, the Pentametrocrinidx# and 
Hypalocrinus. 

No species is known which exhibits a perfect blending 
of these two basic types or their derivatives, though 
there are many mosaics in which both are found side by 
side, either in different individuals, or, more usually, in 
the form of a color pattern, made up partly from one 
base and partly from the other (each being clearly de- 
fined) in the same individual. 

Some mosaic species, such as T'ropiometra afra and 
certain of the Comasteride are peculiar in that some 
specimens belong exclusively to type I (yellow) and 
others exclusively to type II (violet) but none are ever 
mixed. 

The mosaics are, the Zygometride, the Comasterida, the 
Thopimetride except Asterometra, Iridometra, Antedon, 
Erythrometra, Perometra, Hypalometra, Promachocrinus, 
and the Himerometride. 

The data seem to show that the smaller stalked forms 
are invariably and unchangeably yellow, which color may 
be, as in the case of the parrots among birds, equivalent 
to a lack of color. Black is added to the basic color of 
comatulids at all depths, and appears to denote age. 
Blue is added apparently only within 200 fathoms of the 
surface, and increases in intensity to the surface. The 
mosaics are all littoral or shallow water types. 

Species growing among coral or on white bottoms in 
shallow water are very dark in color, often nearly black 
or sharply black and white, while the same species on 
mud may be light yellow and pinkish; or a species may 
be purple and yellow in comparatively deep water, and 
violet and white in shallow water. We seem to be able 
to trace a close connection between color and amount of 
illumination, the blue factor in the coloration increasing 
with the light. 3 


726 THE AMERICAN NATURALIST [Vou. XLII 


There appears to be no direct relation between the 
color of crinoids and their environment. The yellow 
deep water species are very conspicuous in the mud from 
a deep dredge haul, while the color of shallow water 
species, as just indicated, is commonly in great contrast 
to their surroundings. Crinoids can have little to fear, 
because their extremely calcareous organization would 
seem to make them very undesirable as food; on the other 
hand, a strongly contrasting coloration might be of ad- 
vantage in attracting small organisms, as contrast spots 
on flowers do insects; observations in this point would 
not be difficult to make, and might lead to interesting 
results. 

The other echinoderm classes appear to be in general 
subject to the same laws of color change as the crinoids, 
but the records are much more complete and satisfactory, 
and the specimens are not so much changed in preserva- 
tion. They would, therefore, offer an interesting field 
for study. 

These are some of the more interesting inferences to be 
deduced from an examination of the literature on the 
Crinoidea in its present state; and, in view of the great 
geological importance of the group, and its bearing on 
important geologic problems, it is to be hoped that this 
phase of the subject, as well as the systematic and 
anatomical sides will in the future receive its due at- 
tention. 


SHORTER ARTICLES AND CORRESPONDENCE 
EVOLUTION WITHOUT ISOLATION 


Is isolation a factor of evolution? The answer must depend, 
obviously, on what we mean by evolution, as well as upon the 
relations of the facts. Every difference of opinion regarding the 
nature and causes of evolution involves the use of the word in 
a different sense, unless the process is to be renamed with each 
change of interpretation. The choice of words is worthy of care- 
ful consideration, but words should not lead us away from the 
broader issue of biological facts. The practical question is not 
whether the words or their senses are new or unusual, but 
whether the facts are correctly represented. 

Being convinced that changes in the characters of species are 
spontaneous, I apply the word evolution to these spontaneous 
processes of change. This, of course, is not the meaning of 
those who believe that changes in species are brought about by 
external influences working upon normally stationary groups, 
who have been accustomed to think of evolution as a passive 
result of change in the environment, rather than as an active 
process, inherent in the species. 

From one point of view evolution appears as a complex of 
different kinds of environmental influences, from the other as 
a process of growth in. the species, somewhat analogous to the 
development of individual organisms of which species are com- 
posed. In the one case the species are thought of~as being 
-carried or pushed along by their environments, in the other as 
advancing by motions of their own, often in spite of environ- 
mental obstacles and deflections. 

Belief in isolatign as a factor of evolution marks an inter- 
mediate stage of a Gren those who hold that natural 
selection causes evolution, and those who reject selection as a 
cause. The effort is to maintain the doctrine of environmental 
causes by giving selection the assistance of other alleged factors, 
such as isolation, mutation, environmental variation, heredity, 
ontogeny, ete. Nevertheless, this course has its logical dangers 
for the theory of selection, for the placing of much emphasis 
on isolation is practically equivalent to saying that evolutionary 
127 


728 THE AMERICAN NATURALIST [Vou. XLII 


changes go on of themselves, without the need of environmental 
interference. 

If we advance with sufficient confidence in isolation we event- 
_ ually come through to the realization that our alleged environ- 
mental factors are unnecessary as causes, because evolution is 
spontaneous. This approximation of views has been recognized 
by Dr. John T. Gulick who states in the January number of 
the AMERICAN NATURALIST that our interpretations differ only 
in the meaning attached to the word evolution.’ 

I am naturally very much pleased to agree with Dr. Gulick, 
for no other student of isolation has given the subject such 
extensive and thorough study. I subscribe to Dr. Gulick’s state- 
ment that there does not seem to be any essential difference 
between us regarding facts. The difference is that the facts 
appear to me as of more significance than Dr. Gulick has repre- 
sented. In attempting to point out this greater significance I 
have used a different method of expression. 

To say that isolation and selection are factors of evolution 
should mean, in simpler English, that they cause evolution, or 
at least help it along, whereas they do neither. They appear 
to cause or to conduce to evolution only so long as we take it for 
granted that changes in the characters of species are dependent 
upon the subdivision of species, to form additional species. 

e separation of a species into two or more parts allows the 
parts to become different, but there is every reason to believe 
that evolutionary changes of the same kind would take place if 
the species were not divided. That the isolated groups become 
different does not indicate that isolation assists in the process 
of change. It gives the contrary indication that’ changes are 
restricted by isolation. If isolation did not confine the new 
characters to the groups in which they arise, the groups would 
remain alike, instead of becoming different. Thus it appears 
to me that the danger of confusing the issues is much greater 
when we say that isolation and selection are factors of evolu- 
tion, than when we say that they are not factors of evolution, 
however important they may be in multiplying and differentiat- 
ing species. 

Sufficiently narrow forms of isolation no doubt affect plants 
and animals in nature in the same way as the ‘‘intensive segre- 

* Isolation and Selection in the Evolution of Species. The Need of 
Clear Definitions. The American N aturalist, 42: 48, January, 1908. 


No. 503] SHORTER ARTICLES AND CORRESPONDENCE 1729 


gation’’ by which domesticated types are induced to change 
some of their characters, but it does not appear that this in- 
tensive segregation is a condition of evolution. Differences 
between small groups are more obvious and more readily de- 
finable because small groups are generally more uniform, like 
the pieces with uniform patterns which may be cut from a 
variously figured fabric. Isolation is the shears that splits the 
species, not the loom that weaves it. The weaving is done when 
the fabric is broad. The larger and more diversified species 
make the truly constructive evolutionary progress. 

The evolution of a species is in no way dependent upon its 
being split into smaller groups, but is more likely to be hind- 
ered by narrow subdivisions. If the groups are too small they 
degenerate and become extinct, instead of continuing their evo- 
lution. Isolation, though making more species, impedes evolu- 
tion. In like manner, selection favors adaptation, because it 
keeps species from evolving in non-adaptive directions. Isola- 
tion and selection may still be considered as evolutionary factors 
if this time-honored reckoning is too sacred to be changed, but 
they must stand as negative factors instead of positive, if my 
interpretation is correct. 

arwin saw in his later years that evolution is not altogether 
the same as the formation of new species, and used in a letter 
(published after his death), the word ‘‘specification’’ as a 
means of expressing this distinction, a suggestion which I un- 
wittingly repeated in proposing the slightly different word 
“speciation. ’”? 

There are two different classes of cases, as it appears to me, viz., 
those in which a species become slowly modified in the same country 
(of which I can not doubt there are innumerable instances) and those 
cases in which a species splits into two or three or more new species, 
and in the latter case, I should think nearly perfect separation would 
greatly aid in their “specification,” to coin a new word. 

Darwin was concerned to show that species multiply and 
diverge in nature, for this is good evidence of the general fact 
of evolution. Nevertheless, it should not be assumed that all 
forms of divergence represent evolution, or that divergence is 
a true measure of evolution. Divergence may be less than evolu- 
tion, for the evolutionary paths of related groups often follow 

? Factors of Species-Formation, Science, N. S., 23: 506. 

3 Life and Letters of Charles Darwin, 2: 339. New York, 1896. 


730 THE AMERICAN NATURALIST (Vou. XLII 


nearly parallel directions. Divergence may be greater than evo- 
lution when changes are not progressive but sideways or back- 
wards. Mutations, reversions, or degenerations, can take place 
suddenly, without the slow and gradual weaving of new char- 
acters in the network of descent of a species; they involve only 
the suppression of characters or the return to expression of old 
characters that continue to be transmitted in latent form. 

As long as Dr. Gulick lets it appear that the divergencies of 
his snails arise through isolation, I fully agree with him, but 
not when he seems to suggest that isolation and selection produce 
new characters. The fact that isolated groups have no mutual 
sharing of evolutionary progress leaves them free to become 
more and more different, but the isolation does not explain the 
progressive changes to which the differences are due. Isolation 
explains speciation, but does not explain evolution. 

This is the same objection that Darwin made to Wagner’s 
theory of isolation, that it did not help him to understand “‘how 
or why it is that a long isolated form should almost always 
become slightly modified.’’ Dr Gulick explains that his inter- 
pretation differs essentially from that of Wagner, who held that 
even natural selection must have an ‘‘isolated colony’? to work 
upon. Nevertheless, it appears that Darwin’s objection ap- 
plies to Gulick’s doctrine as well as to Wagner’s, for isolation 
only reveals the fact of evolution, while a genuine ‘‘factor’’ 
should do something toward explaining it. 

Such a factor Darwin believed that he had found in natural 
selection, but he saw in isolation alone nothing to aid evolution. 
Darwin took it for granted that species were normally stationary 
and most of his successors still accept this unevolutionary as- 
sumption. With Darwin evolution was a definite process by 
which the characters of a species are changed, but with some 
of our later writers it has become merely a general name for 
a subject of study, whose various phases or branches are loosely 
called ‘‘factors,’’ though they have no apparent relation to the 
original concrete idea of evolution as a process of change in 
species. 

The failure to give a more definite recognition and a name 
( evolution or otherwise) to the processes of spontaneous, pro- 
gressive change in species, appears to me to have prevented the 
attainment of the complete clearness sought by Dr. Gulick in 
the presentation of his elaborate and valuable evidence that only 


No. 503] SHORTER ARTICLES AND CORRESPONDENCE 731 


isolation is needed for evolutionary divergence to become mani- 
est. If Dr. Gulick really agrees with me that evolution is 
spontaneous, I must submit that his adherence to the custom 
of treating isolation and selection as factors has served to con- 
ceal his conclusions, rather than to announce and defend them. 
O. F. Cook. 
WASHINGTON, July 16, 1908. 


A NOTE ON THE SILVERSIDE 

In view of its value as a food fish, and as food for other more 
valuable fishes,* the following note on the habits of the silverside 
has special interest. 

At Chesapeake Beach, Md., April 19, 1908, P. m., the tide was 
rising and probably pretty well up. At points where weed and 
such riff raff was partially buried in the beach, in the wash of 
the ripples which followed one another in, numerous fishes were 
wiggling actively as though stranded. At times one would be 
almost or quite clear of the water, but so active were they that 
the writer, not having a net, was at first unable to capture any. 
They evidently knew what they were doing, as when a spot they 
occupied was approached, they disappeared from it. Finally, 
by striking quickly with a piece of wood at a place where some 
were congregated, three were disabled and secured, which proved, 
as anticipated, to be Menidia menidia. 

Examination of a specimen of beach trash collected where the 
fishes were observed, at the time, shows the presence of a number 
of eggs, apparently of Minidia, strong evidence that the fish were 
spawning. These eggs are one mm. or a little more in diameter 
and bear filaments at one point which attach them to the beach 
material in which they occur more or less scattered. The white 
color of the egg (preserved in alcohol) is relieved by yellow oil 
masses. This spawning ground, if such it was, would certainly 
be exposed at low tide. The species, in this case its northern 
race, has previously been noted to spawn above low-tide level.? 
Chesapeake Bay is neutral ground between the northern and 
southern races of Menidia menidia, and the writer prefers to 
refer the specimens obtained to neither race. 

JOHN TREADWELL MICHOLS. 

U. S. BUREAU or FISHERIES. 

1 W. C. Kendall. U. S. Fish Comm. Rept., 1901 (1902), p. 241. 

? H. C. Bumpus, Science, N. S., Vol. VIII, No. 207, p. 851, Dee. 16, 1898. 


NOTES AND LITERATURE 
BOTANY 


The Origin of a Land Flora.'—Speculations concerning the origin 
of the higher plants have always had a special attraction for 
the botanical student whose work extends beyond the limits of 
mere collecting and tabulation. Perhaps the very fact that we 
can never expect to discover all of the factors concerned with 
the evolution of the vegetable kingdom, and that our conclusions 
are always liable to be materially altered through the discovery 
of new facts, or a different interpretation of those already known, 
gives an added zest to the hunt for new forms or the discovery of 
new facts about those already known which may add another 
stone to the edifice which is being slowly built up. 

The volume under consideration is one deserving more than 
passing attention from the student of plant evolution. Not only 
is it the work of one of the keenest investigators of some of the 
most difficult problems with which the botanist has to deal, but 
the book represents the fruits of many years’ arduous labor, but 
evidently a labor of love, which has yielded results of the utmost 
importance and provides a mine of accurate information, pre- 
sented in an unusually clear and attractive style. From a 
literary standpoint, it might well be recommended as a model to 
some of our scientifie writers who, it must be confessed, do not 
always compare very favorably with their English colleagues in 
the matter of literary form. 

Aside from the wealth of facts brought together in this hand- 
some volume, illustrated by many admirable illustrations, the 
reader constantly encounters speculations, sometimes almost 
startling in their originality, with which he may not always 
agree, but which are certain to set him thinking deeply; and 
we believe that this book will be a great stimulus to the further 
exploration of many obscure, but very important, questions bear- 
ing upon the affinities of the higher plants. 

"The Origin of a Land Flora: A Theory based upon the Facets of 
Alternation. By F. O. Bower, ScD., F.R.S., Regius Professor of Botany in 
the University of Glasgow. Pp. xi + 727, many illustrations. New York, 
The Macmillan Co.; London, Macmillan and Co., Limited. $5.50 net. 

732 


No. 503] NOTES AND LITERATURE 733 


It is not necessary to remind botanists of the high standing 
of Professor Bower’s numerous contributions to science. No 
only has such work as his great monographs on spore-producing 
organs put him in the first rank of morphologists, but his inter- 
pretation of the facts of comparative morphology, and his more 
speculative papers on alternation of generations and the origin 
of the land plants, have strongly influenced all recent theories on 
these important questions. Professor Bower is thus peculiarly 
fitted to treat this difficult subject, and it is with special grati- 
tude to the author that botanists will welcome this admirable 
presentation of the results of his many years’ labors. 

It is generally admitted that the existing land flora, i. e., the 
Archegoniatæ and seed plants, are the descendants of some fresh- 
water plants probably allied to certain green algæ; but the way 
in which these typically aquatic organisms gave rise to forms 
markedly terrestrial in habit is one of the questions about which 
there are very diverse opinions. Professor Bower has long con- 
tended, and we believe that he has overwhelming evidence on his 
side, that the characteristically terrestrial modern plant type, 
i. e., the sporophyte or neutral generation of the ferns and 
seed plants, is the product of the evolution of the zygote or rest- 
ing-spore of some fresh-water algal type, the result of the union 
of the sexual cells, or gametes, and in most cases is an adapta- 
tion to surviving periods of drought to which these plants are 
liable. That is, the sporophyte is from its inception a terres- 
trial or subaerial phase interpolated between the active aquatic 
growth periods. This is the “antithetic”’ theory of alternation, 
and it is this thesis, opposed to the ‘*homologous’’ alternation 
which of late has been defended by a number of eminent botanists 
both at home and abroad, that Professor Bower defends in the 
present volume. 

In his previous work, Professor Bower has elaborated his 
theory of the important part that the sterilization of potentially 
sporogenous tissue has played in the evolution of the sporophyte 
of the higher plants. Particularly has he made this clear in his 
important series of monographs on the development of the spore- 
producing organs of the Pteridophytes. The present volume is 
divided into three parts: (1) The Statement of the Working 
Hypothesis, (2) Detailed Statement of Facts, (3) Conelusion. 

It has been rather the fashion of late to belittle the importance 
of comparative morphology, as it is evident that the plant organ- 


134 THE AMERICAN NATURALIST [Von. XLII 


ism, with its potentially unlimited power of regeneration and 
growth, is extremely plastic and responds promptly to any ex- 
ternal stimuli. Nevertheless, the facts of comparative morphol- 
ogy are too evident to be ignored, and although the modern 
student must carefully check his work by the data furnished 
from experimental morphology, physiology, and paleontology, it 
still is evident that the surest clues to relationship must be 
sought in a comparison of corresponding structures and the facts 
of ontogeny. 

The phenomena of alternation of generations as exhibited by 
the higher plants are familiar to the botanist. The plant shows 
two marked life phases, first the sexual phase, or gametophyte, 
and second the neutral generation, arising from fertilization, 
the sporophyte. In all but the highest plants, the seed plants, 
the gametophyte betrays more or less clearly its aquatic origin. 
It is usually poorly adapted to resist dryness. Water is neces- 
sary for fertilization, as the male gametes are ciliated and the 
mature sexual organs require water for their proper dehiscence. 
In the lower types, like the simple liverworts, the gametophyte is 
relatively larger and plays a much more important réle in the 
plant life than does the insignificant sporophyte, which is short- 
lived and dies as soon as it has shed its spores, whose production 
is the aim of its existence. The sporophyte in the lower forms is 
never an aquatic structure, but receives its water indirectly from 
the gametophyte with which it is permanently in intimate as- 
sociation. 

With the increasing specialization of the Archegoniates, several 
lines of development were inaugurated showing several different 
types of specialization both in the gametophyte and in the sporo- 
phyte. The gametophyte reaches its culmination in the higher 
mosses which seem to show the limit of the possibility of adapting 
the essentially aquatic gametophyte to life on land. The further 
development of the land plants is therefore bound up with the 
elaboration of the terrestrial phase of the plant’s life history, 
i. e., the sporophyte. With the increasing importance of the 
latter there is a progressive reduction of the gametophyte which 
culminates among the Pteridophytes in the extremely reduced 
gametophytes of the heterosporous forms like Marsilia or Selagi- 
nella. | 
It is not likely that any existing liverworts represent very 
nearly the direct ancestors of the Pteridophytes or ‘‘ Vascular 


No. 503] NOTES AND LITERATURE 735 


Cryptogams.’’ It may be said, however, that some remarkable 
parallelisms, if not real homologies, are shown by the peculiar 
Anthocerotes, and there is a progressive development of the 
sporophyte in both liverworts and true mosses which hints at 
least at the course of evolution which finally resulted in the 
entirely independent sporophyte of the ferns. The evolution of 
the sporophyte consists in a constantly increasing development of 
sterile or non-sporogenous tissues, which assume the character 
of green assimilative tissue, etc., and it may finally develop 
definite external organs, roots and leaves, the former connecting 
the sporophyte with the earth and making it quite independent 
of the gametophyte. Finally, spores are produced, always in a 
perfectly uniform manner in groups of four, and the life history 
is complete. 

While only a relatively small number of forms have been 
investigated, it is pretty certain that the sporophytic tissues 
normally have nuclei with twice the chromosome number found 
in the cells of the gametophyte, this being the result of the 
doubling of the chromosomes due to the fusion of the gametes. 
The reduction of the chromosomes occurs in the tetrad division 
resulting in the spores, which therefore possess the normal 
gametophyte number. 

The formation of the sporophyte by apogamy or direct bud- 
ding from the prothallium, and the various buddings of the 
gametophyte from the leaves of the sporophyte, are the strongest 
arguments in favor of ‘‘homologous’’ alternation; but the facts 
of apogamy and apospory may be explained as cases of adven- 
titious budding analogous to so many cases found in the seed 
plants, and much more evidence is needed to show that they are 
normal rather than pathological. 

Comparing the sporophytes of the Bryophytes and Pterido- 
phytes, the latter are distinguished by the development 
of external organs. A more or less conspicuous central axis 
has appendicular organs, leaves, roots and sporangia, the 
latter being the characteristic organs which distinguish the dif- 
ferent types of vascular plants. They may be supposed to have 
arisen from the more or less complete segregation of masses of 
sporogenous tissue from the originally continuous layer of some 
such form as Anthoceros. The gradual evolution of the 
sporangium from the large indefinite sporocysts like those of 
Ophioglossum to the very definite sporangia of the highly 


736 THE AMERICAN NATURALIST (Vou. XLII 


specialized leptosporangiate ferns can be clearly followed in 
existing types. Professor Bower does not regard the Ophio- 
glossales as related to the true ferns, but from this view we feel 
obliged to dissent. 

As might be expected, much stress is laid upon the ‘‘ Theory of 
the strobilus” with which Bower’s name is especially associated. 
This theory assumes that from some bryophytie sporangium, 
perhaps not very different from that of Anthoceros, by the 
segregation of definite sporangia each subtended by a leaf-like 
organ originating from the sterile tissue between the sporangia, 
a cone or strobilus would be derived, i. e., an axis upon which are 
borne a number of leaves usually spirally arranged, each one sub- 
tending a sporangium. This condition is still met with in some 
of the simple species of Lycopodium like L. selago and it is an 
extremely ancient one. 

This theory of the strobilus when applied to the Lycopods has 
very much in its favor, and is certainly the most plausible ex- 
planation yet put forward as to the origin of the Lycopods; but 
is not so convincing when one tries to reduce the ferns also to the 
strobiloid type. It is true that in the Cyeads, which are doubt- 
less of fern affinity, a strobilus is present, but there is very strong 
reason to suppose that it is a secondary condition. 

The chapter on ‘‘ Embryology and the Theory of Recapitula- 
tion” is a very sane treatment of an extremely difficult problem. 
While recognizing that the first students of vegetable morphol- 
ogy went much too far in their insistence upon the importance of 
the exact succession of cell divisions in the young embryo in their 
relation to the subsequent organs of the plant, nevertheless it is 
unquestionable that the early divisions of the embryo are to a ċer- 
tain extent a recapitulation of the early phylogeny. It must be 
remembered that the young embryo has been subjected for 
countless ages to practically the same conditions, and that under 
these conditions certain definite early segmentations should be 
fixed is merely what would be expected. One of these conditions 
is the action of gravity and this beyond question is the most im- 
portant factor in determining the marked polarity of the embryo. 
As to the general application of the theory of recapitulation to 
the later stages of development, as Professor Bower very well 
points out, great caution has to be used, but nevertheless within 
proper limits it is justified. 

Professor Bower maintains that there is but one type of leaf. 


No. 503] NOTES AND LITERATURE 137 


All leaves, he thinks, are primarily sporophylls. Foliage leaves 
are reduced sporophylls and cotyledons, and ‘‘ protophylls’’ mere 
modifications of the foliage leaves. This is not, however, a view 
that can be accepted without some qualification. While un- 
doubtedly on the theory of antithetie alternation, spore-bearing 
structures must have preceded foliage leaves, it may be ques- 
tioned whether these primary spore-bearing structures at least in 
the case of the Ophioglossace and Equisetacex, were not rather 
of the nature of sporangiophores than sporophylls in the strict 
sense of the word. If such is the case, the sterile leaves would 
be outgrowths of the sporangiophores, or even independent struc- 
tures rather than direct metamorphoses of sporophylls. 

From a study of the anatomical evidence, the conclusion is 
reached that the primitive state in the Pteridophytes was one in 
which the axis was structurally dominant in the shoot, and the 
type of cauline bundle a solid monostele. It is also concluded 
that the bipolar, radially symmetrical condition of the sporophyte 
is more ancient than the dosi-ventral condition. 

The problem of the origin of the roots of the vascular plants by 
means of which the independence of the sphorophyte is finally 
secured is recognized as a very difficult one. In some Lycopods 
no root is formed in the embryo until after several leaves have 
been developed, and the name ‘‘protocorm’’ has been proposed 
for this early undifferentiated plant-body, the assumption being 
made that it represents an ancient condition antedating a plant- 
body with true leaves. Professor Bower, however, is inelined to 
doubt the accuracy of this hypothesis. 

While recognizing the great value of the evidence of paleophy- 
tology, and the important contribution that the study of fossils 
has made to our knowledge of the evolutionary history of the 
Pteridophytes it is pointed out how very little light has been 
thrown by this science upon such fundamental questions as the 
origin of the bryophytic sporogonium or that of the leafy 
sporophyte. 

In chapter nineteen are discussed the difficulties of determin- 
ing whether amplification or reduction has been the more im- 
portant factor in determining the course of evolution in certain 
eases. Chapter twenty contains a succinct summary of the 
Working Hypothesis and concludes Part I. 

Over 400 pages of text with many admirable illustrations are 
devoted to Part II, ‘‘A Detailed Statement of Facts.’’ This is 


738 THE AMERICAN NATURALIST (Vou. XLIL 


an excellent account of the sporophytic structures of the Arche- 
goniates and would by itself form an important volume. As 
might be expected in a treatise on land plants, and from the 
author’s previous works, the Pteridophytes are the principal sub- 
jects of study, only two chapters out of twenty being devoted 
to the Bryophytes. Space forbids even an outline of the great 
mass of facts brought together, not the least interesting and im- 
portant being those derived from a study of the fossil forms 
which of late have attracted so much attention. Very little space 
is given to the study of the gametophyte, and while no doubt in 
the problem of the origin of a land-flora the sporophyte is much 
the more important factor, still we can not but feel that in some 
cases, a careful study of the gametophyte would have resulted in 
some different conclusions and would have served as a useful 
check. Thus all the recent work on the gametophyte of the 
Ophioglossaceze emphasizes the strong similarity in the repro- 
ductive organs of these forms and those of the Marattiacee and 
makes more probable than ever a real relationship existing be- 
tween these two orders of eusporangiate ferns.. 

There are recognized three phyla or main developmental series 
of Pteridophytes, the Lycopods, the ‘‘Sporangiophorie Pterido- 
phytes’’ and the ferns, excluding from the latter the Ophioglos- 
sace which Professor Bower thinks at present had best be treated 
as a fourth phylum, although he concludes that there is good 
evidence of a more or less evident affinity with the ‘‘Sporangio- 
phorie Pteridophytes.”’ 

The isolated position of the Lycopods is recognized by Professor 
Bower, and there certainly is very strong reason, both from a 
study of the gametophyte and sporophyte, for assigning to this 
group an origin quite apart from that of the other Pteridophytes. 

The most radical departure from the ordinarily accepted 
arrangement of the Pteridophytes is the establishment of the 
group of ‘‘Sporangiophorie Pteridophytes’’ which includes the 
Equisetales and the fossil Sphenophyllales with which latter 
_ group are included the anomalous Psilotales, which have usually 
been associated with the Lycopods, but whose isolated position 
has for some time been clearly recognized. To the sporangio- 
phorie Pteridophytes Bower also thinks the Ophioglossales may 
be related. The sporangiophore is defined as a more or less 
elongated vascular stalk upon which sporangia are borne. The 
| Sporangiophores are considered to be organs sui generis not a 


No. 503] NOTES AND LITERATURE 739 


modification of either a foliar or cauline organ. The question is 
left open whether the sporangiophore is to be regarded as the 
elaboration of a single sporangium, like that of Lycopodium, but 
it seems to us that the origin of the sporangiophore as a com- 
pound structure from the beginning, is more in harmony with the 
facts of comparative anatomy. 

The acceptance of this view will we believe help to solve some 
of the most puzzling questions as to the affinity of the primary 
pteridophytie stocks. While convinced of the real affinity be- 
tween the Ophioglossacew and the true ferns, we have also more 
than once ealled attention to the marked resemblance between 
the gametophyte of Equisetum and that of the lower ferns; and 
it may be added that there are also correspondences in the embryo 
that are probably not without significance. If then we admit 
that the sporangiophorie Pteridophytes really represent a natural 
division of the Pteridophytes, it is quite conceivable that from 
some common ancestral form having a large green gametophyte 
like that of the lower ferns, two types of sporangiophorie sporo- 
phytes may have arisen, one developing the strobiloid group of 
sporangiophores, as in Equisetum, the other a single large 
sporangiophore like that of Ophioglossum. There is very good 
reason to suppose that the sporangiophore of the Ophioglossaceæ 
is not an appendage of the so-called sporophyll, but is a quite 
independent organ, the sterile lamina being rather an appendage 
of the sporangiophore than the reverse. 

In spite of Professor Bower’s argument we can not but feel 
that the resemblances between the Ophioglossace and the true 
ferns are too numerous and exact to be explained on any other 
ground than that of a real affinity; but this does not lessen 
the importance of his explanation of their probable affinity with 
the Equisetales and Sphenophyllales. 

The classification of the Filicales excluding Ophioglossacew 
is that already elaborated in his memoirs on spore-producing 
members. Three groups of the Filicales are recognized. One, 
Simplices, in which all of the sporangia of a sorus are formed 
simultaneously. Two, Gradate in which there is a definite suc- 
eess in time and space; and Three, the Mixte in which there 
is a succession in time but not in space. Six families are in- 
cluded in the first group. The Botryopteridee (fossil), the 
Marattiacer, Osmundacer, Schizæaceæ (Marsiliacew)? Gleich- 
eniaceæ and Matoninee. The Gradatæ include five families. Lox- 


740 THE AMERICAN NATURALIST [Vou. XLII 


somacee, Hymenophyllacee, most Dicksoniee, Dennstedtiine, 
Cyatheaceæ (Salviniacer)? The remaining families often 
grouped together as Polypodiacew form the group of the Mixte. 

The Botryopterider comprise some of the earliest known fossil 
Filicales. Their affinities, however, are somewhat obscure, and 
the group seems to have been a synthetic one. They show cer- 
tain evidences of affinity with the Marattiacee also with the 
Osmundaceæ and Hymenophyllacee. It might also be suggested 
that a comparison of the sporangium might be made with Botry- 
chium and perhaps Helminthostachys. 

We must pass over with brief mention the very detailed ac- 
count of the ferns which occupies over 150 pages of the text. 
The tendency in the evolution of the sporangium is very clearly 
from the larger eusporangiate type of the Marattiacee reaching 
its maximum in Kaulfussia, where nearly 8,000 spores occur in 
the single sporangium, to the numerous, small leptosporangiate 
sporangia of the Mixtæ where there may be only from 8 to 64 
spores. It may be added that the sporangia of Ophioglossum 
represent a still more primitive type, both in their large size, 
their indefinite limits and very great number of spores. 

The assumed relation of the different families of the Filicales is 
graphically shown in the diagram on page 653. 

Part III is a summary covering some sixty pages. The most 
important conclusion may be briefly stated as follows: ‘‘Certain 
Algæ suggest in their post-sexual phase how the initiation of 
a sporophyte may have occurred, but there is no sufficient reason 
to hold them as being in the actual line of descent of archegoniate 
forms.” ‘‘Both Mosses and Liverworts may with probability 
be held to be blind branches of descent, which illustrate neverthe- 
less phyletie progressions that illuminate the origin of sterile 
tissues from those potentially fertile, and the establishment of a 
self-nourishing system in the sporophyte.’’ ‘‘Jt may accordingly 
be concluded as probable that the prothallus of early Pterido- 
phytes at large was a relatively massive green structure, with; 
deeply sunk sexual organs.” 

The Lycopodiales stand by themselves in the simplicity of the 
sporangial arrangement and constitute a type of extreme an- 
tiquity, which has come down practically unaltered to the present 
day. Their comparative study may be conducted independently 
of other phyla: for there is no reason to think that they were 
: erived from any other known vasenlar type... . The condi- 


No. 503] NOTES AND LITERATURE 741 


tion actually seen in the ‘Selago’ type may be held as truly 
primitive, and Lycopodium Selago, with its imperfectly differ- 
entiated shoot, is in fact a near approach in a living species to the 
ideal primitive form which emerges from wide comparative study 
of the phylum as a whole.’’ 

“The functionally identical parts designated sporangiophores 
and sporangia are cognate parts; it appears probable that the 
sporangiophore is itself a consequence of elaboration of a simpler 
type of spore-producing member, of which the sporangium of 
Lycopodium is an example, while the trabecule in Isoetes and 
Lepidostrobus Brownii suggest a mode of origin of the septate 
state. If this were so, then the sporangiophore would have been 
distinct in its phyletic origin from the bract-leaves, which 
habitually subtend the lig rt tnt members, whether they 
be sporangia or sporangiophores.’’ 

“The phyletic relationship of the Sphenophyllales and Equise- 
tales has undoubtedly been a very close one; the distinguishing 
features are not to be found in the primary plan or construction 
of the shoot, so much as in the secondary modifications of number 
and relation of the appendages, and of their branching, together 
with changes in the originally protostelic structure of the axis. 
Such considerations support the conclusion that the Sporangio- 
phoric Pteridophytes constitute a brush of naturally related 
phyletic lines.’’ 

The Ophioglossales are regarded as an ascending series of 
forms the ‘‘ spike illustrating various steps in the increasing com- 
plexity of a body of the nature of the sporangiophore.’’ ‘‘The 
whole unbranched shoot is a single strobilus bearing leaves of 
which all are potentially fertile and the majority actually so.” 
“The Ophioglossacew appear to have been an upgrade sequence, 
sprung from some sporangiophore stock, and bearing no near 
relation to the large-leaved ferns.’’ 

“The Filicales were ultimately of strobiloid origin, but have 
undergone amplification of their leaves analogous to, but phyle- 
tically quite distinct from what is seen in other Pteridophytes, 
and carried to a higher degree.’ 

‘One chief reason for regarding the lines of the Filicales and 
Ophioglossales as distinct lies in the difference of position of the 
spore-producing members. It has been argued above (p. 633) 
that the soral condition was primitive for ferns, and that the 
sorus is a body similar in kind to the sporangiophore, the two 


742 THE AMERICAN NATURALIST [Vou. XLII 


being alike in function, in structure, and in capacity for fission 
and extension: the number and position are points of difference.”’ 

The Filicales are considered to be a phylum showing funda- 
mentally the strobiloid characters, but secondarily modified in 
relation to their pronounced megaphyllous habit. ‘‘ Accordingly, 
the Filicales appear as the most divergent phylum of homo- 
sporous Pteridophytes.’’ 

‘“‘ Comparison of the several phyla, as represented both by their 
fossil and their modern representatives, leads in each case towards 
the recognition of a primitive type, and its construction in the 
several phyla has certain features in common. The chief of 
these are the definition of axial polarity in the first initiation of 
the embryo: the continued apical growth; the radial construction 
of the shoot: the origin of the appendages laterally from the 
axis by enation, and in strictly acropetal order: a protostelic 
structure of the conducting system of the axis, and a leaf-trace 
composed of a single strand.” 

‘‘ The sporophyte . . . probably arose originally as a structure 
of limited size, and Labeaalied: upon a prothallus of scien gia 
able dimensions, and producing Homosporous Spores.” 

‘The adoption of Heterospory, and of the Seed Habit super- 
vened later. This, while it has led to the final independence of 
the land flora as regards external fluid water for the completion 
of its life-cycle, has brought as a secondary consequence a wide- 
spread reduction.’’ 

‘‘ The final goal of all organic development is the establishment 
of new individuals. The evolutionary story of the sporophyte 
illustrates this in two distinct ways. In the prior and non- 
specialized homosporous forms large numbers of germs are pro- 
duced: . . . consequently amplification of the whole sporophyte 
is the leading characteristic of these earlier types; . . . In the 
later and more specialized heterosporous forms and particularly 
in the Seed Plants with their more refined methods, individual 
precision supersedes mere numbers; and reduction of the propa- 
gative system has been its usual concomitant.’’ 

‘‘ The sporophyte, which is the essential feature in the Flora of 
the Land, is referable back in its origin to post-sexual complica- 
tions: it appears to have originated as a phase interpolated be- 
tween the events of chromosome-doubling and chromosome- 
reduction in the primitive life-cycle of plants of aquatic habit.’’ 

Dovuetas HOUGHTON CAMPBELL. 


* 


No. 503] NOTES AND LITERATURE 743 


PLANT CYTOLOGY 

Apogamy in the Ferns.—It has long been known that the arche- 
gonia in a number of ferns are not functional and that in these 
forms the sporophyte generations arise as vegetative outgrowths 
from the gametophytes. This suppression of sexuality with the 
development of the succeeding generation asexually is termed 
apogamy. Only recently, however, have there been any eytolog- 
ical investigations of the phenomenon. 

Farmer and Digby' were the first to study the nuclear be- 
havior throughout critical phases in the life history of apogam- 
ous ferns. The results, based on forms of Lastrea, Athyrium, 
and Scolopendrium, led these authors to describe three con- 
ditions. 

1. The process of sporogenesis is omitted from the life cycle 
in three varieties of Athyrium Filix-femina and in a form of 
Scolopendrium giving the condition of apospory known for a 
number of ferns. The prothallia arise directly from abortive 
sporangia or from pinne; the sporophytes develop apogamously 
from the prothallia or from unfertilized eggs; and the approxi- 
mate number of chromosomes is retained throughout the life 
cycle. This type of life history brings apogamy into close asso- 
ciation with apospory. The omission of the process of chromo- 
some reduction, characteristic of sporogenesis, gives the gameto- 
phytes the sporophytie number of chromosomes (2x). Apogamy 
seems to be a natural consequence, for gametes would not be 
expected to function under such conditions since they would 
double the number of chromosomes with each nuclear fusion 
and there would be no reduction divisions to bring the higher 
numbers back to the normal. These conditions in the ferns 
agree with certain cases of apogamy among the seed plants 
(Antennaria alpina, Thalictrum purpurascens, and apogamous 
species of Alchemilla and Hieracium) where the reduction 
mitoses are omitted in the ovule and the nuclei of the embryo 
saes contain the sporophyte number of chromosomes, the embryo 
developing from unfertilized eggs or even from synergids. The 
most interesting feature of this type of life history is the de- 
velopment of gametophytes with the 2x or sporophytie number 
of chromosomes, showing that the morphology of this phase in 

1 Farmer, J. B., and Digby, L. cheep in ns dati and Apogamy in 
Ferns. Ann. of Bot., XXI, p. 161, 190 


744 THE AMERICAN NATURALIST [Vou. XLII 


the life history does not depend upon its containing the reduced 
number. 

2. In Lastrea pseudo-mas var. cristata apospora apogamy and 
apospory follow one another in the same manner as described 
above, but the number of chromosomes (probably 60) is so close 
to that of the gametophyte in the type species (72) that it seems 
probable that in this form the sporophyte retains the reduced 
number (x) of the gametophyte. This condition is exactly the 
reverse of that noted above showing that the morphology of the 
sporophyte likewise does not depend upon its containing the 
double number (2x) of chromosomes. 

3. The third and most striking conditions described by 
Farmer and Digby refer to a peculiar migration and fusion of 
nuclei in the cells of the prothallium just before the apogamous 
development of the sporophytes. These observations are re- 
corded from the study of two polydactyla varieties of Lastrea 
pseudo-mas which form their spores with chromosome reduction 
in the usual manner. The nuclear migrations and fusions occur 
in the younger regions of the prothallia, in the wings as well as 
in the thicker portions. A nucleus assumes an elongated form 
with the pointed end against the wall which it is about to pierce. 
A pore is formed through which the nucleus slips and makes 
its way to the nucleus of this receptive cell which usually re- 
mains rounded. The two nuclei come to lie closely pressed 
against one another and gradually fuse. Older prothallia thus 
have fusion nuclei with double the gametophytie number of 
chromosomes (2x) and the cells of the apogamously produced 
sporophytes are found to have nuclei of this type; the authors 
conclude that they are derived from such fusion nuclei. This 
process of migration and nuclear fusion, taking the place of the 
fusion of gametes, finds its analogy in the recent studies of 
Blackman and Christman on the rusts. Just previous to the 
development of the æcidia there is an extensive migration of 
nuclei between neighboring cells so that the cells which give 
rise to the chains of æcidiospores contain conjugate or paired 
nuclei, the descendants of which remain in pairs until the 
nuclear fusion in the teleutospores. Thus in the rusts and in 
these ferns a process of nuclear fusion concerned with vegetative 
cells has apparently become substituted for the fusion of gametes 
which are no longer functional. 


No. 503] NOTES AND LITERATURE 745 


The most recent cytological contribution to the study of 
apogamy in the ferns is by Yamanouchi.? This paper gives a 
much more detailed account of nuclear structure and the be- 
havior of chromosomes than that of Farmer and Digby, and is 
remarkable for the thoroughness of the study of critical phases 
throughout the entire life history. We have already noticed 
a portion of the work in the review of some recent research on 
cilia-forming organs of plant cells in the August number of the 
NATURALIST. Yamanouchi worked upon Nephrodium molle 
which has the advantage of presenting under ordinary condi- 
tions of culture the normal life history of ferns. The apogamous 
development of sporophytes may, however, be readily induced 
in prothallia exposed to direct sunlight and watered from below 
so as to prevent the possible escape of sperms and fertilization 
of archegonia. Such prothallia develop much more slowly than 
under normal conditions. After six weeks the cushion regions 
become markedly thickened, which thickenings indicate the be- 
ginnings of apogamous sporophytes. 

Yamanouchi made very accurate counts of the chromosomes 
throughout the eritical phases of the normal life history pre- 
liminary to a comparison with apogamous conditions. The 
chromosome number in the sporophyte is 128 or 132, which is 
reduced during sporogenesis to 64 or 66 in the usual manner. 
The gametophyte has then 64 or 66 chromosomes which were 
counted in the vegetative cells of the prothallia and in the 
mitoses leading up to the formation of sperms and eggs. The 
fertilized egg has of course the double or sporophytic number. 

Prothallia, which under the culture conditions described above 
produce sporophytes apogamously, have 64 or 66 chromosomes. 
The mitoses up to the 30-50 cell stages are similar to those in 
normal prothallia. After that the growth is very slow and 
there are irregularities in the position of the cell walls with 
reference to the surface of the prothallia. The apogamous 
prothallia produce antheridia in abundance which develop 
motile sperms, the mitoses showing 64 or 66 chromosomes. 
Archegonia are, however, rarely formed on apogamous pro- 
thallia, Occasionally archegonia initials are differentiated, from 
which a central cell is cut off as in normal prothallia, but this 
central cell either remains undivided or produces eggs and canal 

2 Yamanouchi, S. Apogamy in Nephrodium. Bot. Gaz., XLV, p. 289, 
1908, 


746 THE AMERICAN NATURALIST (Vou. XLII 


cells in an archegonium with a poorly developed neck; it is 
doubtful whether such eggs are capable of being fertilized. 

The sporophytie outgrowths on apogamous prothallia arise 
coincident with the development of the cushion region. Super- 
ficial cells on the underside increase in size, and from one of. 
these an apical cell is cut off which becomes the growing point 
of a leaf. Meanwhile there is a rapid division of the neighbor- 
ing cells in the interior so that an area of meristematic tissue 
results which gives rise to the young sporophyte in direct con- 
nection with the prothallial cells. A leaf and stem axis are 
developed from two superficial apical cells, the root tip arises 
endogenously, scalariform vessels appear in the tissue connecting 
the developing leaf and stem, and finally there is differentiated 
the young sporophyte with root, stem and leaf regions. Mitoses 
are easily found in stages of this apogamously developed sporo- 
phyte and always show 64 or 66 chromosomes, the gametophytic 
number of the prothallium. Consequently, in Nephrodium 
molle, there is no doubling of the number of chomosomes in the 
development of apogamous sporophytes through nuclear migra- 
tion and fusion as described by Farmer and Digby for the 
polydactyla varieties of Lastrea pseudo-mas. It has not yet 
. been determined whether these apogamous sporophytes develop 
spores. 

Apogamy in Nephrodium, therefore, presents conditions dif- 
ferent from anything as yet recorded for plants, since following 
normal sporogenesis a sporophyte is developed with the gameto- 
phytic or haploid number of chromosomes (x), and there is no 
place in the life history for the diploid or sporophytie number. 
The ease of Lastrea pseudo-mas var. cristata apospora is appar- 
ently not the same since in that form apogamy follows apospory. 
However it is possible that the apogamous sporophytes of 
Nephrodium may be found at maturity to develop apospory and 
thus swing into a type of life history similar to that recorded 
by Farmer and Digby for the above form of Lastrea. The most 
significant results of Yamanouchi’s investigation is the clear 
evidence that the morphology of the sporophyte does not de- 
mand that its cells contain nuclei with the double or diploid 
number of chromosomes (2x), in other words that the ‘‘number 
of chromosomes is not the only factor which determines the 
characters of the sporophyte and gametophyte,’’ a conclusion 
indicated by the known eases in both ferns and seed plants 


No. 503] NOTES AND LITERATURE 747 


where gametophytes have the sporophytie number of chromo- 
somes. 

A third paper which should be mentioned in connection with 
these two on types of homosporous ferns is Strasburger’s® study 
of apospory in heterosporous Marsilia. Parthenogenesis had 
been reported by Shaw as occurring in 50 per cent. of the female 
gametophytes of Marsilia Drummondii. Nathansohn had in- 
duced parthenogenesis in Marsilia vestita and M. macra by keep- 
ing germinating megaspores at a temperature of 35° C. for 24 
hours and ther allowing them to continue their development 
at a temperature of 27° C. Under this treatment the eggs of 
7-12 per cent. of the spores gave rise to embryos parthenogenet- 
ically while at lower temperatures embryos were only developed 
after fertilization. 

Strasburger found that in Marsilia Drummondiu the nuclei 
of the female gametophyte contain 32 chromosomes which is the 
sporophytie or diploid number present in various vegetative 
regions of the sporophyte. The process of sporogenesis pre- 
sents various irregularities: the number of megaspore mother- 
cells is less than 16 and at times only 4; sometimes the mitoses 
within these cells are reduction divisions of the usual type 
(heterotypic), but in other cases spores are formed only through 
vegetative mitoses in which the sporophytiec or diploid number 
of chromosomes (32) is retained. Such spores give rise to 
female prothallia with eggs having the sporophytic number of 
chromosomes and a parthenogenetic development of the latter 
follows. These conditions differ from those of apospory in the 
fact that spores are developed, but agree in the final result that 
the process of chromosome reduction is suppressed in the life 
history. The microspores showed irregularities in their develop- 
ment and on germination did not produce mature sperms. Two 
other species in the genus, Marsillia macra and, M. Nardu, pre- 
sented similar conditions. 

Perhaps the most important feature of this cytological re- 
search on apogamy is its bearing on current theories of the 
nature and basis of alternation of generations in plants. It 
is perhaps rather generally held by those who accept the anti- 
thetic theory that the differences between sporophyte and game- 
tophyte are in some way concerned with the number of chromo- 


3 Strasburger, E. Apogamie bei Marsilia. Flora, XCVII, p. 123, 1907. 


è 
748 THE AMERICAN NATURALIST [Vou. XLII 


somes, the sporophyte taking its peculiarities because of the 
doubling of the number which results from the sexual fusion of 
gamete nuclei, and giving up these characteristics when the 
number of chromosomes are reduced at the end of the sporo- 
phytic phase. This view that nuclear structure and more par- 
ticularly the number of chromosomes gives the physical basis 
for alternation of generations was originally stated by Stras- 
burger and has received support from a large amount of research 
on life histories throughout the plant kingdom. It has in the 
opinion of some authors reached the stage worthy of statement 
as a law of development, as indicated by the expression x and 2x 
generations applied to gametophytes and sporophytes. 

However, the cytological investigation of apogamy in the 
seed plants as well as in the ferns has shown for a considerable 
number and wide range of forms that the gametophyte genera- 
tion may have the sporophytic number of chromosomes, and now 
in Nephrodium there is established the first instance in which 
a sporophytie generation may develop with the gametophytiec 
number. 

This evidence may be regarded by some as cutting at the roots 
of the antithetic theory of alternation of generations, but this 
does not follow. It is clear that an increase or decrease in the 
number of chromosomes within a certain range does not affect 
the morphology of the phase of the plant’s life history con- 
cerned, and the cause of the specific characters of gametophyte 
and sporophyte must rest upon other factors. What these may 
be is problematical; it is not unlikely that a variety of factors 
is concerned. It is probable that the peculiarities of every 
species demand at least a certain amount of chromatin with a 
specific composition, but there is no reason to assume that this 
must be contained in a fixed number of chromosomes, and fur- 
thermore multiples of the minimum amount required would not 
be expected to introduce new characteristics except as it might 
give increased vigor or vitality. Then there is the cytoplasm 
to be considered and perhaps of even greater importance the 
complex reciprocal relations that must exist between the nucleus 
and cytoplasm. 


BrapDiey M. Davis. 


No. 503] NOTES AND LITERATURE 749 


EXPERIMENTAL EVOLUTION 

Regeneration in Lumbriculus.'—In the August number of Roux’s 
Archiv a paper by Conrad Müller describes regeneration in 
Lumbriculus variegatus and Tubifex rivulorum. The paper of 
70 pages contains 24 figures and 14 full-page tables. Despite 
its bulk one can not help being impressed with its failure to 
contribute much that is new to our present knowledge of regen- 
eration in Lumbriculus. 

Miiller’s chief concern seems to be the extent of the power of 
regeneration. He first studied the power to regenerate a head 
or a tail in Lumbriculus, and from a great many experiments, 
very elaborately described, he found that new heads may re- 
generate 17—22 times in succession, while new tails regenerate 
33-42 times after successive operations. From these facts he 
draws the general conclusion that the power of posterior regener- 
ation is twice as great as the power of anterior regeneration. 
Bonnet in 1741, in his classical investigation of the regeneration 
in Lumbriculus, found also that heads and tails regenerate 
several times after successive operations—only Bonnet never 
obtained regeneration so many times. 

These results of Miiller may be, however, interpreted other- 
wise than that the power of posterior regeneration is greater than 
the power of anterior regeneration, since the worms regenerating 
tails had heads and could therefore feed, while the worms re- 
generating heads could not feed. 

Regarding the relation between length of time during which 
a tail regenerates and the number of segments that are produced 
Miiller sets up the following ‘‘law’’—‘‘The number of segments: 
newly formed stands in direct relation to the length of time 
of regeneration; i. e., during equal periods of time there are 
regenerated posteriorly equal numbers of segments.’’ He also 
investigated the number of posterior segments that regenerate 
after successive operations performed at regular intervals. In the 
course of ten months he cut off the regenerating tails 22 times 
(every 14 days) and found that in this case also ‘‘after repeated 
removals of a regenerating tail the same number of new seg- 
ments is formed during similar periods of time.” He then re- 
fers to my work on regeneration in Lumbriculus and says that, 
‘‘Bei dem von Morgulis und mir behandelten Object scheint 


1 Arch. f. Entwicklungs u. d. Organismen, XXVI, 1908. 


750 THE AMERICAN NATURALIST [Vou. XLII 
dass kein Unterscheid zu machen.’’ But this ‘‘agreement’’ is 
due apparently to a misunderstanding. On the contrary, I got 
the opposite result in my studies on regeneration in Lumbriculus. 
I found that the number of segments formed within equal lengths 
of time decreases the more the time that has elapsed since the 
operation was performed. Concerning the rate of regeneration. 
for similar periods of time (but after successive operations) my 
statement is so simple that it is surprising that it should have 
been misinterpreted. I said—‘‘ .. . in the course of the second 
period of two weeks the pieces regenerate about one half as many 
segments as when regenerating for the first period of two weeks.’’ 
After a third period of two weeks ‘‘the pieces have regenerated 
only about one half as many segments regenerated for the second 
period of two weeks, and about one fourth as many as for the 
first two weeks.’’? 

Miiller quotes my general conclusion, based upon these facts, 
that ‘fa piece of worm, when subjected to the operation of cut- 
ting a few times will produce more new tissue for the same 
length of time than when subjected to cutting only onee,’’ and 

ys: ‘‘Desartiges habe ich ebenfalls beobachted.’’! But unless 
I misunderstood Miiller’s point, his ‘‘law’’ is the reverse of my 
conclusion. He says that a worm regenerates on an average 
25 segments in 14 days; after the following 14 days it will have 
regenerated 50 segments, or 25 segments more, ete., so that the 
number of regenerating segments is in direct proportion to the 
length of time. His tables show also that when the tails have 
been cut off every 14 days 25 new segments regenerate each time. 
In other words, a worm left to regenerate for 8 weeks should 
regenerate 100 segments (25 segments every 2 weeks), while 
another worm in which the tail is removed at the end of every 
14 days regenerates 25 segments after each successive operation, 
and, therefore, will also have formed 100 segments at the close 
of 8 weeks. 

So that a worm that had been operated upon 4 times regener- 
ates 100 segments in the same time in which another worm, 
that had been operated upon only once, also regenerates 100 
segments. This certainly does not uphold my contention; it is 
also evident that Miiller’s ‘‘law’’ is incompatible with my con- 
clusion cited above, yet he seems to find them both to be true. 
Miiller speaks at great length of the regeneration of pieces of 

_ “Jour. Exp. Zool., IV, 1907, pp. 561 and 562. 


No. 503] NOTES AND LITERATURE 751 


Lumbriculus without adding anything new. His discovery that 
single segments are capable of anterior as well as posterior 
regeneration is not new, since I have shown in my paper, pub- 
lished ten months earlier, that single segments regenerate in this 
way. Although Müller reviews my experiments with single seg- 
ments in full detail, he feels dubious as to whether I really did 
have single segments regenerating. The scepticism is due to the 
fact that, according to my description, the worms have been re- 
generating in clean water, and in Miiller’s experience ‘‘war das 
Halten der Tiere in reinem Wasser einfach ausgeschlossen.’’ I 
may therefore mention in this place that pieces of Lumbriculus 
have been reared in clean water even by Bonnet, and that for the 
three years that I have been studying regeneration in Lumbri- 
culus the worms were and are now invariably kept in clean 
water. 

In the chapter dealing with the regeneration of regenerated 

pieces Miiller makes no mention of my experiments, which in 
fact were the first experiments of that nature in Lumbriculus. 
He states that he got the regenerated tail, when detached from 
the parent body, to regenerate new heads or tails 23 times. 
. The fact that Lumbriculus can regenerate its head 23 times 
and its tail 42 times in succession is of considerable theoretical 
importance, and even more so is the statement that regenerated 
pieces are also capable of regenerating heads and tails many 
times in succession. It seems to me that these facts bear di- 
rectly on the hypothesis of formative substances. If such sub- 
stances are connected with the regeneration of a head or a tail 
it would be hard to conceive how such an enormous quantity 
of head- and tail-forming substances has become stored up in 
the cells to insure the possibility of regeneration after 23-42 
operations, unless a further assumption is made that those sub- 
stances themselves are capable of reproduction. Still harder 
would it be to conceive how a regenerated tail, the supposed 
product of tail-forming substances, has become stored up with 
such an abundance of reserve formative substances as to be able 
to produce heads or tails time after time. To make such a 
demand on our credulity would be asking a great deal. 

Miiller’s work on Tubifex is practically a repetition of his 
work on Lumbriculus. There he finds that a head regenerates 
only when 4-6 anterior segments are removed, and does not re- 
generate more than 7 times in succession, while a tail may regen- 


752 THE AMERICAN NATURALIST [Von. XLII 


erate even 40 times. The successive regeneration of heads may be 
checked by the regeneration of the tail. Regenerated parts when 
detached from the worm are not capable of new regeneration. 

The most novel part of the paper is that which describes var- 
ious eases of heteromorphosis, and other malformations in the 
regenerating tail, including the regeneration of double tails in 
Lumbriculus or of triple tails in Tubifex. 

SERGIUS MORGULIS. 
September 7, 1908. 


THE BUDGETT MEMORIAL VOLUME 

John Samuel Budgett, naturalist, explorer, scholar and artist, 
was born in Bristol, England, in 1872. He received his educa- 
tion at University College in Bristol, and later at the University 
of Cambridge, where he received the appointment as Balfour 
Student in Natural Sciences, ‘‘the zoological blue ribbon of 
Cambridge.’’ Here he gave, in 1902, a course of lectures on 
on the ‘‘Geographical Distribution of Animals,’’ succeeding in 
this work the eminent ornithologist, Professor Alfred Newton. 
His work at Cambridge was interrupted and enriched by zoolog- 
ical exploring expeditions to South America and to Africa, 
efforts which from the natural history side were successful in 
the highest degree, but which ultimately cost him his life. 

The first of these, in 1896, was to the Swamps of La Plata 
River at Gran Chaco in Paraguay, in search of the singular 
mud-fish, Lepidosiren paradoxa. The life history and embryo:- 
ogy of this fish was expected to throw much light on the nature 
of the order of Dipnoans to which it belongs. All stages of the 
life history of Lepidosiren were represented in the collection 
made by Mr. Budgett, and the expedition was brilliantly suc- 
cessful. 

On the next expedition, in 1899, he visited the Gambia River, 
where another genus, Protopterus, of the same group of mud- 
fishes is found. 

In the third expedition, in 1900, he visited the Gambia again, 
gathering material for not only the life history of the dipnoan, 
Protopterus, but of different species of the equally interesting 

*The work of John Samuel Budgett, Balfour Student at the University 
of Cambridge, edited by J. Graham Kerr, University Press, Cambridge, 


G. P. Putnam Sons, New York, p. 422 = with many engravings in 
stone. Price y. 00. 


No. 503] NOTES AND LITERATURE 753 


crossopterygian, Polypterus as well. With this was obtained 
material for the study of Gymnarchus and other peculiar fishes 
of the African streams. 

In 1902, Mr. Budgett undertook an expedition to Nyanza and 
the head streams of the Nile. 

A final trip was made in 1903, to the Niger River, in which, 
as in the others, he found species of Polypterus, and with which 
he made most interesting experiments in artificial fertilization. 

In all of these expeditions, Mr. Budget found what he sought, 
and their importance to science can hardly be too highly esti- 
mated. The embryology, taxonomy and geographical distribu- 
tion of these fishes, as well as of different genera of frogs, 
received notable accessions. But Mr. Budgett’s health was 
sacrificed in the work. A recurrent attack of ‘‘blackwater 
fever,” one of the many diseases known as malaria, caused his 
death on January 19, 1903, at the age of thirty-one. 

The publications of Mr. Budgett give the record of these ex- 
peditions, and also discussions of the anatomy, the embryology 
and the breeding habits of Polyterus, Protopterus and other 
species. The batrachians of the Paraguayan Chaco are de- 
scribed in detail, and there is a paper on the birds of the Gambia 
River. 

All these papers of Budgett, with others by Dr. G. A. 
Boulenger, Dr. J. Graham Kerr, J. Herbert Budgett, Richard 
Assheton, Edward J. Bles and Edward T. Browne, based on 
material collected by Mr. Budgett, have been sumptuously 
printed in the present memorial volume by Mr. Budgett’s friends 
and fellow-workers at Cambridge. A delicately appreciative 
biographical sketch of Mr. Budgett is contributed by Dr. Arthur 
E. Shipley. In this are extracts from Mr. Budgett’s diaries, 
showing his fine appreciation of nature and his charming and 
forceful use of English. The plates illustrating this volume 
are worthy of the text, and tne whole is a noble memorial to 
an able naturalist, a brave and lovable man, who fell untimely 
from the hazards of his chosen calling. 

Davin STARR JORDAN. 


754 THE AMERICAN NATURALIST [Vou. XLII 


ANIMAL BEHAVIOR 

Mind in Animals.—Many experimentalists have said in their 
haste that all comparative psychologists are liars; that com- 
parative psychology has no existence. To the experimental 
student of animal behavior, working by the methods of phys- 
iology and zoology, ‘‘psychie factors’’ are merely an irritating 
x, something which he can not perceive in his work, yet which 
the philistine is continually trying to force upon him as the 
cause of what he does perceive. Finding objective determining 
factors for all the objective phenomena, he has no use for the 
psychic factors, and finally decides to make war upon the whole 
worthless mess; Down with comparative psychology! is his ery. 

But it is really only as a technician, intent on the proper meth- 
ods for his own work, that the experimentalist can object to com- 
parative psychology. As soon as he takes a wider view, he 
must perceive that another group of men have made a life spe- 
cialty of precisely the matters that he leaves out of account, and 
he can not expect these men to give up their interest in the dis- 
tribution and development of the phenomena that they are 
studying—of mind and mental processes. And so we have here 
two recent scientific works dealing with the presence of mind in 
animals, both from the experimental standpoint, one by a psy- 
chologist,’ the other by a zoologist. 

iss Washburn’s book is of the greatest interest and value, 

supplying a need much felt. It will be the standard work for 
those who wish to know the present position of scientific animal 
psychology. Concerning the behavior of animals a large body 
of verifiable facts, which have begun to shape themselves into 
a more or less intelligible system, has been gathered together by 
experimentalists, but the latter have given little but hostile at- 
tention to the psychic aspects of the matter. What are the 
implications of this body of facts concerning the distribution of 
psychic processes among animals? This is the problem which 
Miss Washburn sets herself—a problem in which doubtless full 
as many are interested as in behavior as a purely objective 

* Washburn, Margaret F. The Animal Mind: A Text-book of Compara- 
tive Psychology. New York, The Macmillan Co., 1908. $1.60. (Volume 
2 of the Animal Behavior Series, edited by R. M. Yerkes.) 

* Strassen, Otto Zur. Die neuere Tierpsychologie. Vortrag in der zweiten 
allgemeinen Sitzung der 79. Versammlung deutscher Naturforscher und 
Aerzte zu Dresden (1907). Leipzig und Berlin, B. G. Teubner, 1908. 


No. 503] NOTES AND LITERATURE 155 


science. One need not hold that psychic factors are required for 
explanation of the objective facts in order to see the great in- 
terest of this inquiry. 

The author therefore examines systematically the behavior of 
animals, as discovered by experiment, from Amæba to the apes, 
attempting to show what psychie processes are, or may be, im- 
plied. She readily admits the possibility that no psychic proc- 
esses are present at all; but the question is this: If we assume 
that psychic processes are present, and that they follow rules 
like those which they follow in man, then what ones appear to 
be present in the different groups of animals? In answering 
this question, the principle of parsimony is taken as a guide: 
‘‘in no case may we interpret an action as the exercise of a 
higher psychical faculty, if it can be interpreted as the outcome 
of the exercise of one which stands lower in the psychological 
seale.’? The undeniable dangers of this, in the evident fact that 
nature doesn’t always operate by what seems to our limited 
view the simplest means, is expressly recognized, but the prin- 
ciple is thought valuable for holding in check the common 
tendency to attribute higher intellectual faculties to animals— 
a tendency, we may remark, which in very recent times shows 
some inclination to change into its opposite. 

After judicious introductory chapters on Difficulties and Meth- 
ods; on the Evidences of Mind, and on Mind in the Simplest 
Animals, the main divisions of the book are devoted to Sensory 
Discrimination; Spatially Determined Reactions; Modification 
by Experience; the Memory Idea, and Attention. The devotee 
of popular animal psychology will be surprised to find that the 
word reason does not even occur in the index. The facts of 
behavior are set forth clearly and accurately; the student even 
of the strictly objective aspects of the subject will find this per- 
haps the best compendium of the important facts that exists. 
The treatment is throughout sane and conservative; it is analytic, 
systematic and scientifice—not in any sense popular, though clear. 
Slips as to facts and details appear to be rare. All together 
tha treatment appears to one not a psychologist—to one who 

‘‘wants to be shown’’—most satisfactory. e Such a discussion 
of these matters by a competent psychologist has been much 
needed. 

The book gives the experimentalist an opportunity to compare 
as to solidity and general satisfactoriness, his own objective 


756 THE AMERICAN NATURALIST [Vou. XLII 


science, built up by systematizing the verifiable facts alone, with 
that which searches for the psychic processes underneath what 
is observed. The difficulties of making a positive science from 
the unverifiable psychic implications of the actions of animals 
is well illustrated by the conditional and potential forms in 
which the author is forced throughout to clothe her statements. 
Thus, in discussing the psychic aspect of orientation to light 
(p. 184), the predicates of six successive sentences are: we ‘‘can- 
not imagine’’; we ‘‘may conjecture’’; ‘‘is the human experience 
most closely resembling’’; ‘‘appears to be’’; ‘‘may have’’; it 
‘‘is possible that.’’ The experimentalist becomes convinced more 
than ever of the need of building up his own positive science 
of behavior, composed of verifiable propositions, and omitting 
psychic factors—though there is no reason why he should look 
with an unfriendly eye on the attempt, as a separate thing, to 
supply conjecturally the missing psychic elements. 

The difficulties in preparing a satisfactory account of the 
animal mind are further increased by the high degree in which 
the experimental science of behavior shares the provisional and 
uncompleted character of all science. Animal behavior even 
as a purely objective science is merely in its beginning. No 
greater mistake could be made (and this our author evidently 
recognizes) than to suppose that our present experimental 
knowledge is sufficient for defining sharply the psychic powers 
of animals. It is quite possible that the picture of the mind of 
one of the higher animals that might be drawn by an observing 
and judicious dog lover would be much more adequate than the 
rude sketch which experimental science is now able to give us. 
The material furnished by the old Anecdotal School, and by the 
Lovers of Nature, doubtless contains much most-important truth, 
to which the experimental method has not yet succeeded in at- 
taining: only, as Miss Washburn says, it is not possible to tell 
what is true, what false. This material furnishes valuable finger 
posts for experimental investigation, but if we are ever to be 
able to distinguish the true from the false in animal behavior, it 
is necessary to build up the science by that slow and painful 
_ addition of one verifiable fact to another, which has proved the 
method of advance for other sciences, At any given time then 
our experimental science and the psychology based upon it are 
bound to be incomplete and inadequate to the reality. A single 
ee Hinetration must suffice. Miss Washburn shows that a careful 


No. 503] NOTES AND LITERATURE 757 


analysis of the experimental facts indicate that in Crustacea 
there is no color vision. But in the short period since her ac- 
count was written, Minkiewicz has demonstrated experimentally 
a refined color vision in this group, the animals standing with 
much success the test of ‘‘matching colors’’ for their disguises. 
If in so comparatively simple a matter the negative indications 
were wrong, how much dependence can be placed on our now 
having a complete knowledge of what exists in higher spheres? 
Every experimenter knows how near he came to missing some 
important result that he finally reached; he realizes that there 
are doubtless many things equally important that he did miss. 
The positive results of experimental science are stones for build- 
ing; the negative ones are often merely space as yet unfilled. 
Yet such summaries as Miss Washburn gives us of the knowledge 
at any particular time are necessary and valuable, especially 
when, as in the present case, they are put together by one fully 
conscious of the limitations of the subject. 

Zur Strassen* in his lecture before the German Congress of 
Naturalists and Physicians deals with another aspect of mind 
in animals; with a question of the greatest practical interest to 
experimentalists, and of great theoretical interest to all. Are 
‘‘ psychice factors” required for explaining the behavior of ani- 
mals, or can we explain the behavior throughout from the ex- 
perimentally perceivable, objective, factors; can animals be un- 
derstood as physico-chemical machines? Zur Strassen follows 
a course of reasoning which is often begun, but which usually 
stops in the middle; the author carries it to the end, with illu- 
minating results. 

As his guide he takes the principle of parsimony in its widest 
sense—that we shall not assume the existence of any factor which 
is not required in order to explain the results. A further prin- 
ciple, acted upon but not set forth in words, is that mere in- 
crease of complication, no matter how great, does not in itself 
imply a new principle of action. Under these principles he 
examines a series of examples of animal behavior in successive 
stages of complications, from Amoeba to apes, concluding in 
each case that the entire behavior can be understood from the 
standpoint of physico-chemical causality, and that therefore we 
are not entitled to assume the presence of any psychice factor in 
the matter. The author is not inclined to add or subtract from 


3 Loc. cit. 


758 THE AMERICAN NATURALIST [Vou. XLII 


the facts in order to maintain his thesis; he recognizes fully the 
complication of the behavior of both higher and lower animals; 
and he does not claim that we now know the precise physico- 
chemical factors involved in all behavior. But he is able to 
make a good case for his view that all is fundamentally intelli- 
gible physico-chemiecally; in other words, that we could ulti- 
mately make a complete and systematic explanation of what ani- 
mals do, even if we assumed that they have no ‘‘psychie factors,’’ 
no consciousness, at all. The nature of the objective explanations 
which to the author seem satisfactory he can of course merely 
sketch; there is no attempt to give details or claim finality. 
Most significant appears to him, as to others who have studied 
the matter, the making by animals of varied movements, which 
bring them into varied relations with the environment, until 
certain of these relations prove advantageous and therefore per- 
sist. To this way of acting, which has received various names, 
including (from the present reviewer) the unfortunately mis- 
understandable one of ‘‘method of trial and error,’’ Zur Strassen 
gives the expressive name of the ‘‘shot-gun method.’’ Some 
such evidently figurative term is doubtless its best appellation, 
as reducing the temptation to read higher things into it. 

But now we come to the case of man; do our principles of 
interpretation exclude psychic factors here also? Most un- 
doubtedly they do, if the reasoning up to this point has been 
well based. Greater complication there is, but no difference 
in principle; Zur Strassen sets forth that there is no reasonable 
ground for making a distinction between the behavior of man 
and that of animals in this matter. And so, are we led to the 
absurd conclusion that there are no psychic processes, no con- 
sciousness, in man? . 

Here we perceive that two questions must be distinguished— 
two questions which we shall try to formulate even more sharply 
than the author has done, because the usual failure to distinguish 
them has tremendously confused this whole matter. The ques- 
tions are: (1) Does mind exist in men and animals? (2) Does 
mind play such a part in the behavior of men and animals that a 
complete objective explanation of the behavior can not be given 
without taking it into consideration? 

To this second question Zur Strassen answers, No: a satis- 
factory explanation of the behavior of man and animals can be 
_ given without taking into consideration any factors but objective, 


No. 503] NOTES AND LITERATURE 759 


physico-chemical ones. But this has no bearing on the answer 
to the first question: it is no argument against the existence of 
mind in either man or animals, for it does exist in man. It 
may therefore exist in animals: the author concludes, as he is 
bound to, that the probability is that men and animals are alike 
in this matter; that animals also are conscious. His only con- 
tention is that mind is not a factor in determining objective be- 
havior; or as the reviewer would prefer to put it, that a com- 
plete objective explanation of behavior can be given without 
taking into consideration consciousness. 

Zur Strassen’s discussion brings out two points that much 
need recognition. (1) If we adopt the principle of parsimony 
of explanation as a test for the existence of psychic qualities, 
as has been done by various authors, we inevitably come to the 
result that such qualities do not exist, even in places where 
we know, by direct experience, that they do exist. When I 
withdraw my burned finger from the flame, consciousness is 
no more required for an objective explanation of this action 
than it is for the withdrawal of Amceba under similar condi- 
tions, yet in my case there is consciousness, of a very intense 
character. Therefore the result of the application of this prin- 
ciple of parsimony is no test whatever for the existence of 
psychic qualities. A consistent carrying through of the prin- 
ciple places man and animals in the same category, and is there- 
fore, as Zur Strassen maintains, rather favorable than other- 
wise, to the general distribution of consciousness in animals. 

(2) Admission of the existence of consciousness in animals 
is not equivalent to holding that consideration of this conscious- 
ness is required for a complete objective explanation of behavior. 
This point needs to be sharply realized. Look at the matter ex- 
perimentally. A complete explanation, from an experimental 
point of view, is one in which the preceding condition is shown 
to contain differential factors for determining all the differentia- 
tions of the succeeding condition. The question whether con- 
sciousness is a ‘‘factor’’ requiring consideration in objective 
explanations resolves itself experimentally into this: Do we 
sometimes, in analytical experimentation, come to situations 
-= where there are no differences in experimentally perceivable 
factors to account for differences in our results? If we could 
perceive accurately all the objective factors present, should we 
find that sometimes two identical combinations give different 


760 THE AMERICAN NATURALIST [Vou. XLII 


results? If so we might be compelled to conclude that some 
factor x, not perceivable objectively—a psychic factor, perhaps— 
is playing a part. And this of course would mean the bank- 
ruptey of the experimental method; it would mean that things 
happen which are not determined, so far as experiment can 
show; that when differing results appear in two cases, we can- 
not look with confidence for any antecedent differences in the 
conditions to explain them; that by supplying the same con- 
ditions in two cases we can not be sure of getting the same re- 
sults; it would mean that nature plays fast and loose with us 
so far as objective experimentation is concerned. To the ex- 
perimentalist the question whether states of consciousness may at 
times come in and alter his results, without the accompaniment 
of changed objective conditions to which the changed results 
can be attributed, is evidently an intensely practical one, and 
so long as this possibility is held open, it is idle to tell the ex- 
perimenter that he should not concern himself about psychic 
processes. 

But if, as is commonly held, states of consciousness are always 
accompanied by objective physiological conditions, and these 
objective conditions differ when the conscious states differ, then 
of course we should always be able to find satisfactory objective 
determining factors for all differing results; a complete ex- 
perimental explanation of what happens could be given, without 
taking into consideration unknown states of consciousness; the 
objective experimental method would be reliable. There seems 
to be no convineing evidence as yet that it is not reliable and 
sufficient unto itself; it will be best to hold to it till such evi- 
dence appears. And yet, as we have seen, to hold to it as reliable 
and sufficient does not imply in the least that states of conscious- 
ness do not likewise exist. Comparative psychology and a purely 
objective science of animal behavior, complete in itself, may 
exist side by side without the least conflict. 

H. S. JENNINGS. 

1 It does not even imply, I believe, that consciousness is without effect on 
action. A good case could be made for the effectiveness of consciousness, 
in a widened experimental sense, even though a purely objective explanation, 
without gaps, can be given for behavior. 


(No. 502 was issued October 29, 1908.) 


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VoL. XLII December, 1908 No. 504 


SOME PHYSIOLOGICAL EFFECTS OF RADIUM 
RAYS! 


PROFESSOR CHARLES STUART GAGER 
New York BOTANICAL GARDEN 


Ir is probable that no scientific discovery, since the 
publication of Darwin’s ‘‘Origin,’’ has so revolutionized 
our conceptions of natural phenomena as has the discov- 
ery of radioactivity by Henri Becquerel, and of radium, 
by M. and Mme. Curie and Bémont. In the light of these 
epoch-making discoveries we have completely revised 
our concepts of the nature of matter and of electricity. 
The atom, the ‘‘undivided,’’ has been shattered into 
fragments, and a large percentage of the investigations 
in the realm of physics and chemistry now have to do 
with atomic disintegration and the behavior of the re- 
sulting products. 

It was Rutherford and Soddy who first proposed the 
hypothesis that radioactivity is a manifestation of the 
disintegration of atoms, and this hypothesis, chiefly 
through the investigations of Rutherford, has already 
assumed the rank of a theory. 

It would be superfluous to enter here into a detailed 
account of the nature of radioactivity, as understood at 
present. Suffice it to say that the theory elaborated by 

1 The investigations embodied in this paper are treated more fully in the 
author’s memoir on ‘‘Effects of the Rays of Radium on Plants’’ (Mem. 
N. Y. Bot. Garden, 4. Sept., 1908). It has not been thought desirable 
to enter into a discussion here of previous researches on the subject, since 
the literature is fully treated in the memoir. It is a pleasure again to 
express my indebtedness to Mr. Hugo Lieber, of Lieber & Co., New York 
City, whose great liberality in supplying all the radium made the investi- 
gation possible. : 
761 


762 THE AMERICAN NATURALIST [Vou. XLII 


Rutherford involves a conception of the atom as a body 
composed of intricately related units. These units pos- 
sess relatively enormous amounts of kinetic energy, and 
are in rapid orbital motion within the atom. In some 
substances of high atomic weight, such as uranium, polo- 
nium and radium, these units spontaneously escape from 
the atom and fly off into space. Such substances are 
called radioactive, and the emission of these units is 
radioactivity. 

The particles themselves are called ions. They are of 
at least two kinds; one, called the £ particles, very small 
(about one one-thousandth the size of a hydrogen atom), 
bearing a charge of negative electricity, and moving with 
a velocity approaching that of light; the other called a 
particles, about twice the size of a hydrogen atom, bear- 
ing a positive electrical charge, and moving at a much 
lower velocity than the £ particles. The £ particles or 
negative ions are called electrons. 

Streams of negative electrons constitute the so-called 
B rays; streams of positive ions the a rays. Both a and 
ß particles move with velocities that vary between cer- 
tain limits and so the respective rays are complex. 

In addition to the giving off of a and £ rays, radioac- 
tivity involves the emission of electro-magnetic pulses 
in the ether. These are analogous to very penetrating 
X rays, and are called y rays.? 

The enormous velocity of the £ particles, combined with 
their inconceivably small size, renders them very pene- 
trating. They pass readily through matter opaque to 
light, moving between the molecules, or even passing 
directly through the latter, being smaller than the spaces 
by which the atoms are separated within the molecule. 
In their passage through substances they may collide 
with and so dislodge other electrons, thus producing 
ionization. The a particles, owing to their larger size 

* Jean Becquerel (Compt. Rend. Acad. Sci. Paris, 146: 1308. 22 Je 1908, 
147: 121. 13 Jl, 1908) reports the experimental demonstration of the exist- 


ence of free positive electrons, but whether such electrons are involved in 
radioactivity has not been determined. 


No. 504] PHYSIOLOGICAL EFFECTS OF RADIUM RAYS 763 


` and lower velocity, are less penetrating than the £ par- 
ticles, but are much more effective ionizers. The y rays 
belinve as X rays. 

In addition to the three types of rays above described, 
radioactive substances are the source of a heavy, inert 
gas, belonging to the argon family. This gas, named by ` 
Rutherford the emanation,’ is itself radioactive, giving 
off only a rays. 

Studies of the physiological effects of radium, there- 
fore, must take into consideration the three types of rays, 
desdribed above, and also the radioactive gas, the emana- 
tion. In the experiments recorded below, the radium, in 
the form of radium bromide, was contained in Sealed 
glass tubes, or employed as a thin coating on a suitable 
surface. In the former case only X and y rays were 
available, as the a rays and the emanation can not pass 
through the walls of the tubes. In the latter case the a 
rays together with the emanation were also available. 

The effects of radium upon plants have been investi- 
gated by Dixon and Wigham* in Great Britain, by Koer- 
nicke® in Germany, by Guilleminot® in France, and by 
several others. Without going into the details of their 
work it may be stated that the general conclusion from 
their experiments is that the rays exert either a retard- 
ing or an inhibiting effect on physiological processes. 
Koernicke, however, found some evidence that accelera- 
tion of activity might follow exposure to the rays under 
suitable conditions. 

My own investigations have led to the conviction, al- 
ready reported,’ that radium rays act as a stimulus to 

®The use of the plural ‘‘emanations’’ to designate all the rays and 
influences coming from radium, has been somewhat common in biological 
papers. It has no warrant, is only confusing, and should be abandoned. 

* Nature, 69: 81. 1903. Proc. Roy. Dublin Soc. Sci., N. B., 10°: 178. 
1904. Notes Bot. School, Trinity Coll., Dublin, 1: 225. 

5 Ber. Deut. Bot. Ges., 22: 148, 155. 1904; 23: 324, 404. 1905. 

“Compt. Rend. Acad. Sci. Paris, 145: 711. 1907; Compt. Rend. Assoc. 
Française Adv. Sci., 36': 389. 1907; 36: 1344. 1908; Compt. Rend. Acad. 
Sci. Paris, 145: 798. 1907. 

7*<Bffects of the Rays of Radium on Plants.’’ New York, 1908. 
(Mem. N. Y. Bot. Garden, Vol. IV.) 


764 THE AMERICAN NATURALIST [Vou. XLII 


plants. If this stimulus ranges between a minimum and 
an optimum point an excitation of function results; if be- 
yond the optimum point a depression of function, passing 
to complete inhibition as the strength or duration of the 
treatment is increased beyond the point of optimum 
stimulation. The following experiments are chosen 
from nearly 200, and indicate the nature of the evidence 
upon which the above conclusions are based. 

Eight dry seeds of the bean (Phaseolus—Henderson’s 
‘‘ Long Yellow, Six Weeks’’) were placed in moist sphag- 
num with their hilum-edges touching a rod coated with a 
Lieber’s radium-coating® of 10,000 activity.® After 


Effect of radium rays on the germination of Lupinus albus and 


Fic. 1. 
Phaseolus. 


three days (70 hours) exposure, the radicles of the ex- 
posed seeds averaged 13.18 mm. in length, those of a con- 
trol set 15.12 mm. Ten dry seeds of Lupinus albus were 
similarly exposed to a coated rod of 25,000 activity and, 
*See Gager, l. c., Chapt. VI. 
°” The unit of activity is the activity of uranium. Radium of, e. g., 
10,000 activity is 10,000 times as active as uranium 


No. 504] PHYSIOLOGICAL EFFECTS OF RADIUM RAYS 765 


at the end of three days (70 hours) the radicles of the 
exposed seeds averaged 3.81 mm. in length, those of the 
control set 21.80 mm. The retardation of germination 
and growth following this treatment is illustrated in 
Figi; 

A row of timothy grass seed (Phleum pratense) was 
sown on a moist blotter. Over the center of the row was 
suspended vertically a sealed glass tube containing 10 mg. 
of radium of 1,500,000 activity in the end of the tube 
nearest the seeds. The distance from the tube to the 
seeds was about 5 mm. A second row was also arranged 
as a control (not exposed to radium). At the end of 
eleven days the control seedlings were all of about the 
same height and color (normally green) and averaged 
30 mm. in height. The exposed plants were entirely 
etiolated directly under the radium tube and for a 
radius of 4 mm. on each side. The height of the seed- 
lings gradually decreased from 30 mm. (average) at the 


| 
| 
| 


Fic. 2. Effect of radium rays on the germination and growth of timothy 
grass. 


ends of the row, to 3 mm. at the center under the radium 
(Fig. 2). 

Twenty seeds of ‘‘Lincoln’’ oats (Avena), with the 
glumes removed, were placed in two parallel rows with 
the radicle ends touching, and the embryo-side upper- 
most. Over them was laid the sealed glass tube of 
radium bromide of 1,500,000 activity, resting on the 
radicle ends of the seeds. After an exposure of 6 days 


766 THE AMERICAN NATURALIST [Vou. XLII 


and 15 hours, these grains, together with twenty similar 
but unexposed ones, were planted in flower pots in soil. 
The control grains germinated two days sooner than those 
exposed, and, at the end of seven days after planting, 
the seedlings from the exposed grains were just appear- 
ing above the soil, while the control plants were several 
centimeters tall (Fig. 3). 


Fig. 3. Effect on ss germination and growth of oats of exposing the ‘ites 
before planting. Cf. . 4. 


In order to test the effect on germination and growth 
of radium rays in the soil, 16 unsoaked grains of ‘‘Lin- 
coln’’ oats were sown in soil in a flower pot, in 3 con- 
centric circles, at distances of 7 mm., 22 mm. and 
45 mm. from the center of the pot. At the center 


Fic. 4. Acceleration of germination and growth of oats by placing a sealed 
glass tube of radium in the soil (R). The tube in C is empty. Cf. Figs. 3 and 5. 


No. 504] PHYSIOLOGICAL EFFECTS OF RADIUM RAYS 767 


the sealed glass tube of radium (1,500,000 X) was in- 
serted vertically into the soil, with the end containing the 
radium at a depth of about 5 mm. below the surface. 
A control culture was similarly arranged with an empty 
glass tube. After an exposure of 106 hours the seed- 
lings in the pot containing the radium were all up, and 
were most decidedly taller than those in the control cul- 
ture, three of which were not yet up, and all of which 
were less developed in every way than those exposed to 
the radium. 

The plants in the outer circle of the exposed culture 
averaged 50 mm., those in the middle circle 46 mm. and 
those in the inner circle 42 mm. taller than those in the 
corresponding circles of the control (Fig. 4). 

On the sixth day after planting the radium tube was 
changed to the control culture, and the empty tube re- 
placed the radium. The pot © was then irradiated (CR) 


Fie. 5. e same cultures as those shown in Fig. 4, six at ae The 
radium. tube is now in C (CR), and R serves as the control. Cf. 


768 THE AMERICAN NATURALIST (Voir XLII 


and R became the control. At the end of five days after 
this change the plants in CR (Fig. 5) were nearly as 
tall as those in C and the exposure was photographed. 
Eventually the plants in CR exceeded those in R, and 
thus, by changing the radium tube from one pot to the 
other, the growth of either culture could be accelerated 
at will. 

In order to ascertain the effect on growth of exposing 
seeds for the same length of time to radium of various 
degrees of activity, three sets, A, B and C of six dry seeds 
each of Lupinus albus were exposed to rays from radium 
in sealed glass tubes by laying the tubes against the 
hilum-edges of the seeds. The duration of exposure was 
91.5 hours, and the strengths of the radium as follows: 
A, 1,800,000 x ; B, 1,500,000 X ; C, 10,000 X ; D, control, 
not exposed. At the close of the period of exposure the 
seeds were planted in soil, each set in a different pot. 
The experiment was photographed eleven days after the 

seeds were planted (Fig. 6), and curves of growth of the 


Fic. 6. Effect on growth of exposing seeds of Lupinus albus for 91.5 hours 
to rays from radium of various degrees of activity. From left to right the 
activity was 1,800,000; 1,500,000; 10,000; C, control. Cf. Fig. 7. 


four cultures are shown in Fig. 7. It is seen at a glance 
that the effect of the rays on growth varies directly with 
the degree of activity of the radium. The apparently 
anomalous rise of the 1,800,000 curve during the first 
days record (Fig. 7) is due either to poor exposure of 
some one of the seeds of that culture, or represents an 
individual variation in resistance to the rays that was 
= not compensated for because of the small number of 
seeds necessarily employed.1° 


Millimeters 


No. 504] PHYSIOLOGICAL EFFECTS OF RADIUM RAYS 769 


To show the effect of duration of exposure to radium 
of the same activity, four sets of six dry seeds each of 
L. albus were taken. Three of them A, B and C, were 
exposed as follows to the rays from 10 mg. of radium 


Experiment 29. 
Effect of strength of activity on growth. 


\ 


pont! 5 Laan 
JE beca | pecs 


ee - 


\O 
\ 
A 

\ 


eA : A7 1809000 
yo Amean 
a b . 


ee 
. £ a” 
K ke 

Va 

Ge 4” 

7 
VA 
Z 

0 1 Q 3 4 6 7 
AY 
Fre. 7. 


bromide of 1,800,000 activity, in a sealed glass tube: A, 
72 hrs.; B, 50 hrs.; ©, 26 hrs.; D, control, not exposed. 
The seeds were then planted, without soaking, in sepa- 
rate pots of soil. At the end of 5 days the average 
heights of the seedlings above the surface of the soil were 
as follows: A, 88 mm.; B, 95 mm. ; C, 134.50 mm.; D, 145 
mm. Inspection of the curves of growth for the four 
cultures (Fig. 8) shows that, for a given activity of 
radium, the effect on growth varies directly with the 
duration of the exposure. 

The retardation of starch formation by a green leaf 
in the light was shown as follows. A nasturtium 
(Tropeolum) plant was removed to the light after being 
in darkness for 18 hours. Under one of the leaves, 

w The length of the tube did not permit of satisfactorily exposing a 
larger number of seeds at one time. 


770 THE AMERICAN NATURALIST [Von. XLII 


empty of starch, was placed a Lieber’s radium-coated rod 
of about 25,000 activity. The rod was placed under the 
leaf in order not to shade the latter. After an exposure of 
twenty-four hours the leaf was decolorized and tested 
with iodine. Abundant starch was found on the edge 
of the leaf farthest from the rod, but only very slight 


22 D ae 
p 


26 hrs — en 
—_——— 
es 
deai 
ë 


(em osstsnissssooese ost eee® 


Millimeters 


Experiment 27. | 
Effect of duration of exposure =m] 
on germination of Lupinus albus. 


3 4 5 oon 
Days 


Fig. 8. 


traces elsewhere, especially in the region that was directly 
over the rod. A print of the leaf was made by laying it 
over a sheet of velox paper in a printing frame and ex- 
posing it to light. In this way the portions having less 
starch, and, therefore, more transparent, showed darkest 
on the print (Fig. 9). 

All attempts to demonstrate a direct tropistic response 
to the rays, by either roots or shoots, were unsuccessful. 
When, however, a sealed glass tube containing about 50 
mg. of radium bromide of 10,000 activity was suspended 
horizontally in a culture solution, at a distance of from 

_ 2-10 mm. from the root-tips of L. albus, the roots curved 
a toward the tube (Fig. 10). In an experiment in which 


No. 504] PHYSIOLOGICAL EFFECTS OF RADIUM RAYS 771 


a culture solution was substituted for the tap-water, the 
angle of curvature was more abrupt (nearly 90°). It 
seems probable that this is an indirect response, due to 
the effect of the radium rays on the water or solution. 


10. Curvature of 
ed 


1G. 
root-tips toward a se 
glass tube of radium bro- 
and the light. The darker portion repre- mide (10,000x) in a cul- 
sents the region exposed to the rays. ture solution. 


Whether the rays increase the number of ions of an 
electrolyte in solution is still a debated question,"* but the 
physiological effects of tap-water exposed to the rays 
seem to leave no doubt but that the latter alter a solution 
in some way. How, we do not know. 

Micheels and de Heen!? were among the first to study 
the effect of the rays on plant respiration. Under the 
conditions of their experiments respiration was always 
retarded. In one of my own experiments, soaked grains 
of wheat (Triticum) weighing, when dry, 2 gm., were sup- 
ported on a moist blotter in a tumbler over a saturated 
solution of KOH. Over the wheat, and in contact with 
the grains, was placed the sealed glass tube of radium of 
1,500,000 activity. The CO, given off by the wheat was 
absorbed by the KOH, and the consequent rise of mercury 
in a graduated tube of small bore was taken as an index 

1 Cf. Mem. N. Y. Bot. Garden, 4: Chapt. XIX. 1908. 

2 Bull. Acad. Roy. de Belgique Class. Sci., p. 29. 1905. Bot. Cent., 98: 
646. 1905. 


772 THE AMERICAN NATURALIST [Vou. XLII 


of the rate of respiration. Under such conditions, and 
with radium of 10,000 as well as 1,500,000 activity, the 
result was always an acceleration of respiration, as is 
shown in Fig. 11. It is probable that, under certain con- 


pee | 7 
Experiment 79. do 
Effect of radium rays on respiration P 
of germinating wheat. First 8 hrs. PLA © \ a 
or <a gant 
F 
a 
r 
o 1 r 
30 $ mi 
26° p A. wes SEAS AOE 3 Temp. dee Se ieee A 
A 
29 o > on a. 
As 
a 
0 
9:30 . 10:30 11:30 12:30 1:30 2:30 3:30 4:30 5:30 
Time 


Fio. 11. 


ditions of exposure, the rays would retard or completely 
inhibit respiration. 

In order to test the influence of the rays on alcoholic fer- 
mentation, mixtures of commercial yeast in ferementation 
tubes were exposed to the rays. A piece of compressed 
yeast weighing 1 gm. was thoroughly mixed in 100 c.c. 
of tap-water, and equal portions of this mixture were 
placed in fermentation tubes. Into these tubes were 
placed sealed glass tubes containing radium bromide of 
activities 7,000, 10,000 and 1,500,000. A fourth fermen- 
tation tube with no radium served as a control. The rate 
of fermentation was measured by the rate of evolution 
of the gas. The results of all experiments indicated a 
decided acceleration of fermentation under the influence 
of the rays, and, as the curves in Fig. 12 clearly show, the 
amount of acceleration is in direct proportion to the ac- 
tivity of the radium. 

No reference has yet been made of the fact that radio- 


activity is a factor in the normal environment of plants. 


No. 504] PHYSIOLOGICAL EFFECTS OF RADIUM RAYS 773 


I have elsewhere!* noted this, and have presented’* a 
mass of evidence from the realm of physical science indi- 
cating the general distribution of radioactivity. It exists 
in air and soil, in spring-water, and in freshly fallen rain 
and snow. Potassium, one of the essential elements of 


= Experiment 87. i 
; : 2 
se Alcoholic fermentation. EA 
PE E 3 ee 
Temp, 0s 
20| ba TE x 
ee att O L_— 
30° ee aE idee: ne 
12 FoR EE ne OP ee 
< ane i i- PER N 
por esosdeceeseoorodee 
4 aves 7,909 euesedqeooorrrer ted 
Ol. 


12 

Time of day 

Fig. 12. Acceleration of alcoholic fermentation by radium rays. 
plant food, has been found by Campbell to give off £ 
rays,!> and some evidence has also been found that 
calcium possesses the same property. The researches 
of many investigators have clearly demonstrated the gen- 
eral occurrence in nature of free negative electrons. 
These discoveries not only add to the interest and im- 
portance of the study of the physiological rôle of radium 
rays, but also point out the way for further investigation. 

An arrangement devised by Mr. Hugo Lieber facili- 
tated the study of the effect of a radioactive atmosphere 
on germination and growth. The apparatus is clearly 
shown in Fig. 13, and needs little further explanation, 
except to say that the hollow cylinder, R, has its inner 
surface coated with a Lieber’s radium coating. The 
bell-jars fit tightly on to the ground glass plates, and a 
eurrent of air is kept passing through the jars by attach- 
ing the tubing from the lower tubulure to an exhaust 
pump. ‘The air passing through the radium-lined cyl- 
inder carried with it the emanation given off by the 

13 Science, N. S., 25: 263. 1907. 

u Mem. N. Y. Bot. Garden, 4: Chap. II. 1908. 

15 Proc. Cambridge Phil. Soc., 14: 211. 1907. Nature, 76: 166. 1907. 


774 THE AMERICAN NATURALIST [Vou. XLII 


radium, and thus the plants were subjected chiefly to the 


influence of a rays. 
In the experiment here described, dry seeds of timothy 
grass were sown on the surface of the soil in two pots 


Fie. 13. Apparatus for growing seedlings in a radioactive atmosphere. Cf. 


Fig. 14. 


and placed, one under each of the bell-jars. After five 
days, during which a continuous current of air was de- 


No. 504] PHYSIOLOGICAL EFFECTS OF RADIUM RAYS 775 


livered over the cultures, the seeds were found to have 
germinated and grown uniformly under the control jar, 
but, in the culture exposed to the emanation, the seeds 
immediately under the funnel through which the emana- 
tion was delivered had entirely failed to germinate. The 
other seedlings of this culture were only very slightly less 
vigorous than those of the control (Fig. 14). 


ae i 


ai" 


Fie. 14. Result of growing timothy grass in a radioactive atmosphere as 
shown in Fig. 13, R, exposed cultures; C, control. 

To further investigate the effects of this radioactive 
air, five germinated seeds of L. albus with radicles over 
10 mm. long were marked with India ink 10 mm. back 
from the root-tip. These seedlings were then suspended 
vertically, five under each bell-jar. The air, normal in 
one jar, radioactive in the other, was forced into the bell- 
jars by means of a rubber bulb, the blasts being given at 
irregular intervals of from two to twenty-four hours. At 
the end of the first twenty-four hours the average length 
of the exposed radicles was 19.00 mm., and of the control 
only 12.10 mm. At the end of the second twenty-four 
hours the average lengths were, for those exposed 23.30 
mm., for those unexposed, 12.70 mm. The curves of 
ain for this experiment are given in Fig. 15, showing 
the acceleration in rate of growth under the conditions 
imposed. 


776 THE AMERICAN NATURALIST [Vou. XLII 


The growth of roots was retarded in water exposed 
for twenty-four hours to the rays. The experiment was 
made as follows: Into 100 cc. of tap-water, in which 
sealed glass tubes of radium bromide had lain for twenty- 


30 


Pi 
-_ 
- 
prio — 
en ot a 
20 ad 
Q 
S 10 “A 
7 
7 
7. Experiment 0 0. 
Z, 
0 
10 11 12 
Days 


Fic. 15. Acceleration of growth of roots of Lupinus albus in a radioactive 
atmosphere. 


four hours, the radicles of four germinated lupines were 
suspended up to an ink mark, placed 10 mm. back from 
the root-tip. Three cultures were arranged: A, with 
radium of 1,800,000 activity; B, with radium of 1,500,000 
activity ; and C, with no radium, serving as a control. At 
the end of five days the average lengths of the hypocotyls 
were, for A, 79.62 mm.; for B, 85.50 mm.; for C, 117.75 
mm. The result, then, was a retardation of growth, in 
direct proportion to the degree of activity of the radium 
to which the water was exposed (Fig. 16). 

Following up the suggestion in the discovery that 
freshly fallen rain is radioactive, several experiments 
were made with a view of ascertaining the effect of this 
radioactivity on plant growth. Rain-water was caught 
in the open, in chemically clean glass dishes, after about 
four hours of rain, so that the air was well washed. This 
water was kept carefully covered, for one month, when an- 
other opportunity presented itself of collecting another 
lot of rain under similar favorable circumstances. The 


No. 504] PHYSIOLOGICAL EFFECTS OF RADIUM RAYS 777 


experiment was set up immediately after the last collec- 
tion, using radicles of Lupinus albus, immersed to a 
measured length of 5 mm. in both the fresh and the stale 
water. Two parallel experiments, A and B, were run, 
120 


Millimeters 


110 | | 
100 Experiment 5 “ 
Effect on growth of water wd 
70 exposed to radium rays. oe 
80 Tee ii sf 
A ae 
= 2 TAE 
; . . pe 
60 
50 
40 
30 
20 Oe s 
10 r 
0 os 
5 6 7 § m. 10 


ea A month 
each with a ‘“‘fresh” and a ‘‘stale’’ culture. At the end 
of 48 hours the lengths of the radicles averaged, for set 
A, 23.50 mm. fresh; 27.50 mm. stale: for set B, 22.38 mm. 
fresh; 27.00 mm. stale. The curves of growth are shown 
in Fig. 17. The experiments of which this is a type indi- 
cate that, as a result of its radioactivity, freshly fallen 
rain water tends to retard the growth of roots. We have 
as yet no data on the effect of this factor on the activities 
of the shoot. 

Profound histological changes follow exposure to the 
rays. These effects are due chiefly to a disturbance of 
the normal functioning of the cambium, and are in har- 
mony with results of experiments on animals, in which it 
has been shown that embryonic tissue is more sensitive 


778 THE AMERICAN NATURALIST [Vou. XLII 


than any other. After an exposure of seeds under cer- 
tain conditions, the cambium is frequently entirely lack- 
ing, all of the cells in the given organ having passed over 
into the mature state. The treatment appears to ac- 
celerate the approach of senescence. 


24 ; : 
cS L - 
; fi yor | 
& KiS A 
: L ner cee A 
oo" 
, gwt 
; : EA oh 
8 gate a : 2a i 
4 
0 : 
0 10 20 30 J | 


Hours 
Fic. 17. Retardation of growth of roots of Lupinus albus by freshly fallen 
rain water. Cf. Fig. 16. 


Exposure to the rays also induces marked irregu- 
larities in mitosis. This is shown, among other ways, 
by the failure of some of the chromosomes to take part 
in the organization of the daughter nuclei. Usually such 
chromosomes organize smaller, nuclear-like structures 
within the daughter-cells. In one instance they were ob- 
served to be undergoing an independent karyokinesis at 
one side of the main mitotic figure. Interesting possi- 
bilities are here suggested, along the line of experimental 
mutation. 

Experiments like those described in this paper have 
been many times repeated with confirmatory results, and 
seem amply to justify the general conclusion, earlier 
stated, that radium rays are a stimulus to plant activities. 
The reaction to a stimulus between the minimum and 
optimum points is an excitation, or acceleration of the 
given process; the reaction to an over (superoptimal) 
stimulus is a depression, or retardation of function, and, 
if the stimulus is sufficiently intense, complete inhibition 
or ultimate death. 


ON THE ORIGIN OF STRUCTURES IN PLANTS 


W. A. CANNON 


Desert BOTANICAL LABORATORY 


Te systems of organs of which a higher plant more 
especially is composed generally hold an intimate phys- 
ical relation to one another. They are bound together 
so intimately by reason of their position in root or shoot 
that the growth, development or response to stimulus of 
one is in a very great measure molded by the growth, 
development or reaction of all the rest. In addition to 
these considerations, when the origin of tissues or of or- 
gans is being investigated, account must also be taken of 
the nutrition of the special organ as well as its especial 
relation to environment external to the plant of which it 
is an integral part. Thus the complex physical interrela- 
tions, and the physiological correlations as well, make 
the study of the functions, and behavior of the individual 
tissue, or organ, as a possible independent unit one of 
great difficulty. These general facts probably hold for 
plant tissues as a whole, but one system, namely, the 
trichomal system, offers a favorable field in which to 
study the origin, development and biological relation- 
ships of plant organs, inasmuch as it is comparatively 
little affected by other tissue systems. Beyond growing 
out of epidermal cells, remaining permanently attached 
to the epidermis, and deriving nourishment from the sub- 
jacent cells, the trichomes lead an independent existence, 
and in origin, development and form are not directly in- 
fluenced, as the other tissues are affected, by the pressure 
of enveloping tissues, and in certain plants, as Franseria 
dumosa, the trichomes go one step further on the road 
to independence, in that they are chlorophyll-bearing and 
in a sense probably auto-trophic. For these and other 

779 


780 THE AMERICAN NATURALIST [Vou. XLII 


reasons the trichomes are favorable for the study of the 
origin of plant structures, as I recently found while work- 
ing on certain hybrids, a detailed account of the results 
of which will be given in another place. 

The walnuts, to which reference is made, bear 4 or 5 
types of multicellular hairs, besides certain abnormal and 
one aberrant type. These are composed of 6, or 8 cells, 
or about 16 or about 32 cells. A close study of the de- 
velopment of the trichomes, in which mitotic figures were 
used as indicators of the course of cell division, showed 
the following to be facts: (1) In the earliest stages of 
development of all of the normal trichomes, the sequence 
of the first two, or three cell divisions was the same; 
(2), the sequence of cell divisions of the 6-celled and 
the 8-celled trichomes, during the entire development, is 
consistent; (3), the 8-celled trichome recapitulates faith- 
fully the sequence of cell divisions of the 6-celled type 
up to the six-celled stage, and then adds two divisions in 
an order not departed from. Certain facts indicated that 
the late cell divisions of the two larger forms of trichomes, 
namely, those with about 16 and about 32 cells, do not 
hold to a sequence so closely, but further study of these 
difficult trichomes might modify this conclusion. These 
facts indicate that all of the multicellular trichomes may 
have originated in a common ancestral form and that by 


` 
ve 
‘4 
aes 
pusa 
‘ 
‘ 


aoe ee 


Fic. 1. Semi-diagrammatic sketches of 6- and 8-celled trichomes to show 
the Cell Lineage of each. The numbers refer to the sequence of the formation 
of 1 


No. 504] ORIGIN OF STRUCTURES IN PLANTS 781 


arrested development, or other differentiation, the various 
types of trichomes now to be found in Juglan’s species 
. have arisen. Certain of the trichomes are evidently more 
closely related to one another than to other types, and 
thus the trichomes are not all of equal age, but have been 
derived from an ancestral form at various times in the 
history of the plants which bear them. It is very prob- 
able, for instance, that the 6-celled type is more nearly re- 
lated to the 8-celled type of trichome, than it is to either 
of the larger forms, but it would be difficult to say which 
represents the more ancient type. In development, and 
probably in origin, the types of trichomes thus behave 
as if they were separate organisms, or independent units 
of a complex organism. This is not the same as saying 
that each type of trichome is a ‘‘ unit character,’’ al- 
though certain observations which I have made on the dis- 
tribution of trichomes in another plant, as well as the re- 
version of the trichomes in the second generation of 
Juglans californica X Juglans regia would justify this 
conclusion. Should it be the experience of other observers 
also that each type of trichome has its peculiar area of 
distribution in a plant, the conclusion that each form 
of trichome represents a separate unit character could not 
be avoided, and from such structural studies as above re- 
ported we should be able to trace their very origin as 
separate portions of the tissue of the plant. 

In addition to the normal types of hairs in walnuts, 
as given above, there are also other types. Of such, there 
are certain abnormal forms which are evidently related 
to the already existing trichomes, of which they are slight 
modifications, and one aberrant type which is essentially 
different from these. The origin of the aberrant form 
was seen also, and was found to be as different from the 
mode of origin of the normal trichomes as the mature 
aberrant type is different from the mature normal form. 
In brief, its departure from the normal takes inception in 
the orientation of the first cell wall, which is longitudinal 
in place of being transverse as is usually the case (Fig. 


782 THE AMERICAN NATURALIST [Vou. XLII 


2). Consequently it happens from this single initial de- 
viation, there arises a form of trichome, unrelated to 
other existing types, and, consequently, of which it can 
in no wise be said to be a modification. In fact the new 
hair is a mutation, and its history shows in at least one 
way how such variation has its origin. In this instance 
there is no disappearance of intermediate forms of tri- 
chomes, since for structural reasons there can not be such. 


E 


ao 


Fic. 2. Mature aberrant Trichome and two-celled aberrant Trichome, in 
which the first cell wall is laid down parallel to the long axis of the mature hair. 


We therefore find in Juglans that the different types 
of multicellular trichomes may take their origin in one 
of two ways, namely, they may arise as modifications of 
types already existing in the plant, which is apparently 
the usual manner, or they may arise suddenly and hence 
provide points of departure for subsequent trichome 
formation and differentiation of which they would be the 
ancestral type. 

The physiological reasons for the differentiation of the 
trichomes were not investigated, but observations indi- 
cate a close relation between size of hair and the position 
occupied by it on the plant member, and suggest that the 
factor of nutrition may be important in inducing certain, 
at least, of the irregularities noted. 


THE ORIGIN AND FORMATION OF THE FROTH 
IN SPITTLE-INSECTS? 


BRAXTON H. GUILBEAU 


CORNELL UNIVERSITY 


Durine the summer months one observes upon trees, 
shrubs, herbs and grasses, numerous masses of froth- 
like material, which resemble large drops of spittle. An 
examination of a frothy mass soon discloses the presence 
of a small insect, greenish, brownish, or whitish in color, 
depending upon the species under observation. This is 
the immature nymphal stage of an insect belonging to 
the homopterous family Cercopide. So far as it is 
known, all the members of this family surround them- 
selves with such a secretion, in which they spend their 
nymphal life. I have had under observation three 
species, Aphrophora parallela Say, Lepyronia quad- 
rangularis Say, and Clastoptera proteus Fitch. Each of 
the species studied in this locality makes a characteristic 
froth, as may be easily recognized by a little study. 

While there is much which has been written upon the 
production of froth by the insects of this group, the opin- 
ions of the many writers are-very much at variance. This 
is especially true regarding the more recent literature on 
the subject. For this reason it seemed desirable to un- 
dertake a detailed study of this subject and to determine 
what organ or organs were concerned in the production 
of this secretion. This study consisted not only of field 
observations and laboratory experiments, but of a de- 
tailed study of the histological structures concerned. 

This work was carried on in the Entomological Labo- 
ratory of Cornell University, and to its director, Pro- 
fessor J. H. Comstock, I am indebted for many courtesies. 
The problem was suggested by Dr. W. A. Riley, and to 
him I am indebted for constant aid and advice. 

1 Contribution from the Entomological Laboratory of Cornell University. 

783 


784 THE AMERICAN NATURALIST [Vou. XLII 


HISTORICAL 


Gruner (1901) has given a very extended and excellent 
historical account of the work of individual writers on 
these insects. It is intended here merely to group the 
views held by the various writers, at the same time adding 
the opinions held by writers since the appearance of 
Gruner’s paper. 

As far as the writer has been able to determine from 
original sources, there are seven theories which have been 
advanced in explanation of the production of the froth. 
This does not take into account the belief of the southern 
negroes, who claim that the frothy masses are caused by 
horseflies, neither does it take into consideration the opin- 
ion formerly held by many, that it is the product of the 
stars, nor the view that it exudes from the ground. 

Isidorus, who lived in the sixth century, is cited by 
Gruner as the first to write on this subject. He believed 
that the froth was the spittle of the cuckoo bird, and that 
from this secretion the cercopid spontaneously generated. 
Mouffet (1634) and other writers came to the same con- 
clusion respecting the origin of the spittle and insect. 
Aldrovandi (1610), in his Ornithologia, strongly denies 
this assertion, but fails to enlighten the reader as to the 
true solution of the problem. 

According to Gruner’s account, Bock (1546) appar- 
ently believed that the froth was the product of plants 
and he gave a list of the plants producing it. 

John Ray (1710) states that the spittle mass was 
caused by the insect found within the mass, and believed 
that it was expelled from the animal’s beak. He was 
upheld in this view even in recent times by as prominent 
an authority as Uhler (1884). Fabre (1900) states that 
a clear fluid comes out of the beak and that to this fluid 
the insect injects air bubbles by grasping air with the 
last pair of lateral prolongations of the ninth abdominal 
segments. 

_ Blankaart (1688) believed that the froth came out of the 
anal opening of the insect. In this view he is supported 


No. 504] ORIGIN OF FROTH IN SPITTLE-INSECTS 785 


by Poupart (1705), Frisch (1720), Geoffroy (1764), De- 
Geer (1773) and others. Morse (1900) modified this 
view somewhat in that he gives as his opinion that what 
comes out of the anus is a ‘‘ clear somewhat viscid fluid ”’ 
and that by means of appendages at the extreme tip of its 
abdomen the insect secured a moiety of air by grasping it, 
so to speak, and then instantly releasing it as a bubble 
into the fluid. Gruner (1900 and 1901) states that the 
fluid is exuded from the anus and passes under the body, 
flowing into a pocket-like space where it becomes im- 
pregnated with air which comes out of the stigmata 
located in the pocket. 

Porta (1900 and 1901) believed that there were open- 
ings on the dorsum of Aphrophora which were connected 
with oval glands little distinct from the hypodermis. - He 
describes them as arranged at the base of the excretory 
canal in numbers of five, six or even fewer, indistinctly 
separated from one another. To these glands he ascribed 
the function of producing the fluid. He also states that 
the bubbles are blown into the fluid by the method de- 
seribed by Morse. 

Girault (1904) states that ‘‘ during the process of se- 
cretion the fluid flows slowly from a point near the anal 
opening, and gathers between the legs, where, by their 
alternate agitation, it becomes mechanically mixed with 
air and forms cushions of air bubbles,’’ and he further 
states ‘‘that the air is taken in at each up and down mo- 
tion of the abdomen and that during this dipping proc- 
ess the ventral plates are in transverse motion like jaws, 
and that it is probable that the secretory glands are be- 
tween them.’’ From this we should infer that he thought 
that it came from special secretory glands and not from 
the anus. 

Berlese (1907) believes that the froth is secreted by 
glands found upon the seventh and eighth abdominal 
segments, previously described by Batelli (1891). 

In the following it is proposed to discuss the evidences 
bearing upon each of the current views presented above 


786 THE AMERICAN NATURALIST [Vou. XLII 


and give in details the observations made to clear up the 
confusion. 
METHODS 

The methods used in the biological observations are 
given in the body of the text. I refer here only to those 
used for the examination of the histological structures. 

In preparing the tissues of the spittle insects for his- 
tological examination various methods of fixing, killing 
and staining were used. The best results were obtained 
by killing in hot water and then transferring immediately 
into Fleming’s strong solution for twenty-four hours. 
Tissues killed directly in hot Fleming’s fluid, while giving 
satisfactory differentiation of organs like the testes, in- 
testine and fat cells, gave poor results with the glands. 
Very good results were obtained by killing in hot Gilson’s 
fluid. 

Good serial sections of the nymphs were obtained by 
infiltrating in paraffine 54° C., while adults imbedded in 
62° C. paraffine gave better sections. Sections were cut 
from three to ten microns. 

Staining was done on the slide with iron hematoxylin 
or Delafield’s. Whenever the latter was used the tissues 
were counter-stained in eosin. 

In order to get satisfactory preparations of the glands 
in surface view the tissues were killed in hot Gilson’s 
fluid and allowed to stand for one half hour after having 
been opened and the fat carefully removed. After wash- 
ing in seventy per cent. alcohol and a few drops tincture 
of iodine, the specimens were stained in borax carmine for 
a few minutes, dehydrated, cleared and mounted in bal- 
sam. Great care must be observed in teasing the fat 
away from the glandular region, otherwise the cells will 
be disarranged. 


PERSONAL OBSERVATIONS UPON THE PRODUCTION OF THE 
FroTH 

I first studied the gross features of the froth formation 

in several specimens. A large specimen of Aphrophora 


No. 504] ORIGIN OF FROTH IN SPITTLE-INSECTS 787 


parallela was taken from the frothy mass and by means 
of a camel’s hair brush was thoroughly freed from every 
particle of froth. The specimen was then placed upon a 
dry twig. It soon inserted its beak in the plant and 
gradually increased in size. It projected the tip of its 
abdomen extensively and then retracted it. This opera- 
tion it repeated several times. Suddenly a small drop of 
a clear liquid appeared at the very tip of the abdomen, 
coming distinctly out of the anal opening. Observations 
made with a hand lens upon other parts of the body, es- 
pecially in the region of the dorsum, failed to show any 
fluid whatever. The small drop was soon joined by an- 
other, and these in turn were followed by many others, 
the whole mass of fluid passing down on the ventral side 
of the body along the channel formed by the sternites 
and the prolongations of the pleurites (Figs. 1 and 6). 
Again, the fluid was noticed to be fairly oozing out of 
the anal opening. After a quantity had accumulated 
about the body of the insect, it was noticed that the last 
pair of legs, sometimes also the second pair, would reach 
out to the region of the seventh and eighth abdominal 
segments, then rub against the body and against one an- 
other as if in the process of mixing substances. After 
the fluid had been well mixed and the surface had been 
covered by it, it was next observed that the nymph moved 
the tip of the abdomen out of the liquid, opening up the 
pair of lateral appendages of the ninth abdominal somite, 
which immediately closed again. Then with a downward 
movement these parts were immersed in the liquid and 
the appendages, upon being opened, released a particle of 
air in the fluid. This operation was repeated many 
times, with the result that the insect was soon covered 
with air bubbles, which gave the ch teristic covering 
a froth-like appearance. It was noticed that by changing 
the size of the air-grasping pocket, the insect is able to 
make bubbles of any size. For that reason, the bubbles 
in the smaller forms are always very much smaller than 
those of the larger spittle insects. It is partly this feature 


iii. aaa THE AMERICAN NATURALIST [Vou. XLII 


which determines the above-noted cl teristic appear- 
ance of the froth of the different species. The insect 
does not always wait until the body is completely covered 
with fiuid before injecting the air into it. 

In order to make sure that the larger portion of the 
fluid came only from the anus, the latter was closed by 
a plug of lens paper, which being capped with balsam, 
and then allowed to dry for a few moments, closed the 
anal opening perfectly. The insect, upon being placed on 
a twig, after locating a satisfactory place, soon pierced 
the plant with its beak and began feeding. It rapidly 
increased in size and became much distended and swollen. 
Although observed for over three hours not a single drop 
of fluid came out. In a specimen whose anal opening had 
not been carefully sealed a drop of liquid succeeded in 
coming out of the tip of the abdomen, on the side of the 
filter plug. Thus it was demonstrated, as any one who 
desires to repeat the operation may, that at least one of 
the constituents of the froth is emitted from the anal 
opening, and that the views of Mouffet, Porta, Berlese 
and Girault are not correct, for according to their inter- 
pretations the closing of the anus would not interfere 
with the production of the froth. 


HISTOLOGICAL STUDY OF THE STRUCTURES OF THE GLANDS 
oF BATELLI 


While it is seen that the greater portion of the liquid 
from which the froth is produced is derived from the anus, 
there arises the question whether there are not other or- 
gans, the secretion of which may take a prominent part 
in the formation of the spittle. 

In the pleural region of the seventh and eighth abdom- 
inal somites very large hypodermal glands are located. 
To the naked eye these glands are not easily discernible 
upon the nymph, their positions being detected only if 
there happens to be a large supply of their secretion. 
Under the hand lens when the abdomen is extended, there 
are to be noticed whitish patches, even when the secretion 


No. 504] ORIGIN OF FROTH IN SPITTLE-INSECTS ` 17189 


has been completely removed. These, which lie in about 
the mid-pleural region, are somewhat pulvinate in shape, 
but by no means regular in outline. 

As to the location of these glands there seems to be 
some difference of opinion. Batelli (1901) describes 
them as being located on the last two abdominal segments. 
Misinterpreting Wheeler’s (1889) account of the adeno- 
podia of the first abdominal segment in embryos of Nepa 
and Cicada, he erroneously homologizes these glands of 
Aphrophora with such structures, but rejects Wheeler’s 
view that they are homologous with abdominal append- 
ages. Porta (1900) and Gruner (1901) believed that 
these glands are situated on the seventh and eighth 
abdominal segments, while recently Berlese (1907) gave 
as his opinion that they were located on the eighth and 
ninth abdominal somites. I am of the opinion that Porta 
is correct, for there is no evidence that the first abdominal 
segment has been suppressed and they are clearly on 
the existing seventh and eighth abdominal somites (Fig. 
2). Morever, this would harmonize more fully with Ber- 


Fig. 1. Ventral View of full- Fic. 2. Dorsal View of younger 
grown Nymph of L. quadrangu- Nymph of L. quadrangularis, x 40. 
laris, x40. Pl, pleural prolonga- 1-11, tergites ; Sc, secretion. 


ons; Se, secretion of the glands 
of Batelli; g, groove. 


790 THE AMERICAN NATURALIST [Vou. XLII 


lese’s own labeling of the segments in the abdomen of 
Cicada plebeia (Gli Insetti, Fig. 297, page 263). 

An examination of the cuticle in the region: of the 
seventh abdominal gland under the 3 mm. objective of the 
compound microscope shows that it is free from hairs, 
which are more or less abundant in other regions of the 
body. Under the one-sixteenth-inch oil immersion ob- 
jective one is able to readily discern numerous minute 
pores (Fig. 3), giving it the appearance of very fine in- 
grained leather. These pores are more or less regularly 
distributed over the surface, equally distant from one 
another, and of equal size pea the region. Sim- 


Fig. 3. Surface View of Fic. 4. Surface View of the Epithelium 
the cuticular Pores overly- of the Glands of Batelli, x 250. 
ing the Glands of Batelli. 


ilar pores were found on the eighth abdominal pleura. 
The most diligent search failed to reveal any such struc- 
tures in any other region of the body. As I shall em- 
phasize later, these are the openings of true cuticular 
pores through which the secretions of the underlying 
glands emerge to the surface. 

Specimens of the spittle nymphs were opened and the 
underlying fat carefully removed. Although it is difficult 
to separate the fat from this region without destruction 
of the glands, enough was removed so as to present a 
satisfactory area for study. The cells (Fig. 4) in good 
preparations were clearly defined, mostly hexagonal 
(occasionally pentagonal), though somewhat irregular 
from mutual pressure. They lie in close apposition ‘to 
one another. The nuclei are large, round or oval, and 
in surface view appear situated in the center of the cell. 


No. 504] ORIGIN OF FROTH IN SPITTLE-INSECTS 791 


They are granular and occupy a large portion of the cell. 
The protoplasm in the region of the nuclei is highly gran- 
ular and is readily stained. In the periphery of the cell 
it is not stained as readily, appearing somewhat hyaline. 
In some of the preparations made with specimens which 
had been killed in alcohol there were a number of inter- 
cellular spaces, while in the preparation of the glands 
which had been fixed immediately after removal of the 
fatty tissues such appearance was lacking, except in 
places where it was obviously due to mechanical cause. 
Arnhart (1906) gives a photomicrograph of a surface 
view of the wax-glands of bees, and explains these open- 
ings as tracheal in nature. Their presence is, in my 
opinion, due solely to faulty preparations rather than to 
the presence of any special tracheal ramifications. In 
general appearance the cells in surface view are very 
similar to those of the wax-glands of the honey-bee. A 
comparison with the excellent figures of Dreyling (1905) 
serves to bring this out clearly. 
In longitudinal sections of A. parallela and Lepyronia 
quadrangularis the hypodermal cells of this region are 
greatly enlarged (Fig. 5), and strikingly resemble those 


Ss 
Sa 
2 easy 
3> ET RESNE 
LET PAN E SEDA 
SS —— ee ee 
AN 


Fic. 5. Frontal Section of the Glands of Batelli in the Nymph of Lepyronia 
quadrangularis, x125. Gl, glandular epithelium; hy, ordinary hypodermis of 
the body-wall; sp, spaces. 


of the wax-gland of the bees. Each gland has the appear- 
ance of a curved band or bow, the central portion of which 
is thick, while it gradually tapers towards the ends. The 
same thing is noticed in the cross section (Fig. 6). This 
appearance is due to the general decrease in height of the 


792 THE AMERICAN NATURALIST [Vou. XLII 


individual cells from the center to the periphery of the 
glandular mass. The cells in the main body are sharply 
defined, being separated from one another by distinct 
lines of demarcation. Near the margin of the gland it is 
not so easy, however, to define the contour of the indi- 
vidual cells, these passing gradually into the regular type 


EE g 
Fic. 6. Cross section of the seventh Abdominal Segment showing the Glands 
of Batelli, x110. Sg, sternal groove; pp, pleural prolongations. 


of hypodermal cells. In this type the nuclei are smaller 
and the cell outlines are not discernible. In sections of 
the gland the cells are not uniform in width, due to the 
fact that the sections pass in the center of some and in 
the sides of others. The glands of the two segments are 
about equal in size. In sections that pass through the 
long axis they are 292 microns in Lepyronia quadrangu- 
laris, and in A. parallela they are 465 microns. Most of 
the sections which the writer has made show clear spaces 
(sp., Fig. 5) between the individual cells. These spaces 
vary in their appearance in different preparations, and 
evidently represent artifacts due to faulty fixation, rather, 
than the normal appearance of the cells. 

In the middle of the glands the cells are high, cylin- 
drical or cubical. On the margin they are low. In the 
last instar of the nymphs of A. parallela they are 30 
microns in en and 18 microns in width in the center 


No. 504] ORIGIN OF FROTH IN SPITTLE-INSECTS 793 


of the gland, while in the margin the measurements are 
approximately 16 by 14 microns. The nuclei are round 
or oval and: are situated in the lower margin of the cell. 
They are very granular and stain deeply. They are 
about 8 by 6 microns in dimensions. The protoplasm 
is highly granular, much more so in the region of the 
nuclei and in the margin underneath the chitin. The 
cuticula over the gland is about 8 microns thick, while 
that of the adjacent body wall is 12 microns. 

If one makes satisfactory sections through the glands 
of these insects it is very easy to see extremely minute 
openings in the overlying cuticula leading from the 
glands to the surface. These outer openings correspond 
to those described above. For each canal there is a pore. 
Their distribution over the gland is regular. They are 
unbranched, perpendicular to the surface of the cells and 
about equally distant from one another (Fig. 7). As has 


nit i 
rani ia UT X 


Fie. 7. Enlarged Portion of the Gland of Batelli, showing the cuticular 
canals, x 275. Cu, cuticula; c, canals. 


been stated, similar pores do not occur in other regions 
of the body wall. Berlese (1907) and many other writers 
hold the opinion that true pores are never present in the 
chitin, and that substances are not conducted through the 
chitin by any such arrangement. Dreyling (1905), in a 
paper already referred to, figures and describes canals in 
the chitin overlying the wax cells of the social bees, and 
ascribes to these the function of conveying wax to the 
outer surface. Many writers agree with Dreyling in this 
view. My studies of the cuticula in the spittle insect 
convinces me that such true pores are present and they 
do serve as conduits in carrying the secretions of the 
underlying glands to the surface. It was noticed on 
several occasions that in specimens dropped in hot Flem- 


794 THE AMERICAN NATURALIST [Vou. XLII 


ing’s fluid the region of the glands was always im- 
mediately darkened, while the other parts were not so 
affected. This was evidently due to a more rapid pene- 
tration of the fluid at the point, or the staining of the 
secretion within the pores. 

The above-described glands are also present in the 
imago, but in this stage they are very greatly reduced in 


<< 
h 
Fic. 8. Gland of Batelli in adult Insect, x 200. G, gland; h, ordinary 
hypodermis. 


high cylindrical condition of the cells noted in the 
nymphal stage is absent, and the sharply defined cell 
divisions are not present. The protoplasm is scanty and 
not so granular as in the nymphal stage. Many of the 
cells show signs of breaking down. Scattered through- 
out the glandular mass one finds many irregularly shaped 
bodies which are stained of a pinkish color by the eosin. 
No spaces were noticed between the individual cells. 
The nuclei are round and oval and of about the same size 
noted for the nymph. They show signs of breaking 
down, in fact some of them are surrounded by clear space, 
and many had a shrunken appearance. 


Function oF THE GLANDS oF BaTELLI 


Morse (1900) states that ‘‘On the sides of the seventh 
and eighth abdominal segments may be clearly seen leaf- 
like appendages, which are possibly branchial in nature.’’ 
These he figures and describes as ‘‘extremely tenuous and 
having the appearance of clusters of filaments, slightly 
adhering together and forming lamellate appendages 
similar to the gill-like appendages seen in the early stages 
of Potamanthus,’’ though he admits they do not have the 

definiteness of these structures. Specimens he placed in 


No. 504] ORIGIN OF FROTH IN SPITTLE-INSECTS 195 


water lived for some time and he concludes that the above- 
referred to structures have a respiratory function. These 
so-called branchial tufts of Morse (sc., Figs. 1 and 2) are 
nothing more nor less than the plates of secretion from 
the glands described above. This secretion is not fila- 
mentous, but appears rather very granular. It is very 
easy to remove these flakes of wax by means of camel’s 
hair brush from the segments to which they adhere but 
slightly. The secretion is not soluble in alcohol and 
swells up after being allowed to stand in water for some 
time. It has a very striking superficial resemblance to 
beeswax. 

The resemblance of these glands to the wax-glands of 
the honey bee, in the shape of the cells and in the location 
and appearance of the nuclei is very striking. This fact 
has already been pointed out by Batelli (1891), Gruner — 
(1901) and others, who also find much in common with > 
the cells of the wax-glands of coccids and other Hemip- 
tera. Gruner (1901) thought that the waa served to 
line the ‘‘pocket’’ already mentioned so as to enable the 
air to penetrate it the better, and prevent the inflow of 
the fluid while the bubbles of air were being blown into 
the fluid. Porta (1900) accepting Morse’s curious error 
regarding the presence of branchie, considered this thick- 
ened epithelium as a supporting structure for these sup- 
posed gills. Carrying further Batelli’s misinterpreta- 
tion of Wheeler’s work, he regarded these ‘‘supporting 
structures’? as homologous with the abdominal append- 
ages of the embryos of Nepa and Cicada. 

I am convinced that these glands secrete a mucil- 
aginous substance which is utilized by the insect in the 
production of the spittle. Mixed thoroughly with the 
anal secretions it serves to render this viscid and thus 
to hold the air bubbles blown into it.. This view is based 
upon the following experiments. 

The region of the seventh and eighth abdominal seg- 
ments of several specimens of the nymph was carefully 


796 THE AMERICAN NATURALIST [Vou. XLII 


seared by means of a heated needle. These specimens 
were then placed on a plant and, although badly treated 
by the operation, soon found suitable places and began 
to suck up the juices, and as usual became enlarged. In 
the majority of cases each nymph began to emit drops of 
fluid from the anal opening. Although during the emis- 
sion of this fluid the caudal segments of the abdomen were 
extended and retracted as in the normal specimen, in no 
case were bubbles formed within the secretion. This was 
true even after twelve to fourteen hours. In order to 
test whether this was due to the lack of some constit- 
uent normally secreted by the injured glands, air was 
blown into the fluid through a finely pointed tube; in- 
stead of being retained, none of the air balls aia nod 
in the fluid more than five to ten seconds. On the other 
hand, bubbles blown into the secretion of unseared speci- 
mens held in it for a very long time. This experiment 
was repeated many times over and always with the same 
result. 


` OTHER SUPPOSED SOURCES OF THE SECRETION 


Besides these glands, other structures have been men- 
tioned as participating in the formation of the froth, and 
in order to determine what part they played in it they 
were given careful consideration. 

Berlese (1907) regards the glands of Batelli as the 
sole source of the secretion. This, my observations, con- 
firming in part those of Morse and others, have shown 
conclusively to be incorrect. While I hold that the above- 
mentioned glands contribute an important element to the 
spittle, there is not the slightest question but that the 
fluid portion is emitted from the anal opening. 

We have seen that Porta (1900) considered the secre- 
tion as formed primarily by glands scattered among the 
hypodermal cells of the abdomen and opening to the 
surface through prominent canals, and that these were 
especially abundant in the region of the stigmata. All 
ome could be noticed were the openings of trichopores. 


No. 504] ORIGIN OF FROTH IN SPITTLE-INSECTS 197 


A study of longitudinal and cross sections failed to show 
any such glands as described and figured by Porta. 
There are to be found the prominent oenocytes which are 
more numerous in the ventral surface of the animal. 
Berlese (1907) dismisses this view by stating that it is 
these oenocytes which Porta has mistaken for spittle 
glands. While this is doubtless in part true, I believe, 
as near as can be judged by the imperfect illustrations, 
that Porta was also misled by oblique sections through 
the body wall. 

Porta (1900) mentions an oval gland which he says is 
situated in the fourth somite near the intestine, which 
he further states is ductless and has no connection what- 
ever with the intestine or any other organ. He thinks 
that it may be concerned in the formation of the spittle, 
though he gives no tangible reason in support of this 
view. After careful study of a number of series of sec- 
tions I failed to find any such independent gland and I 
am convinced that he in reality had under observation 
one of the cephalic glands and that of course it has no 
relation to the spittle secretion. 

This same writer describes other glands hich he con- 
siders are concerned indirectly in the production of the 
spittle. These he describes as being situated in the 
latero-ventral region of the third, fourth, fifth and sixth 
abdominal segments. He states that there are four pairs 
of these glandular masses, and in these ramify numer- 
ous tracheæ. He was unable to find any external openings 
to these glands and did not notice their connections with 
any other organs. The fact is that they are accessory 
reproductive organs, and that in perfect series their con- 
nection with this system may be most readily traced. 


SuMMARY 


The secretion of the spittle insect is made up from two 
sources: 
The fluid portion is the anal secretion into which the 


798 THE AMERICAN NATURALIST [Vou. XLII 


insect by means of caudal appendages introduces numer- 
ous air bubbles. 

The glands of Batelli secrete a mucilaginous substance 
which, added to the anal fluid, renders it viscous and thus 
causes the retention of the air bubbles. 

The so-called branchial appendages of Morse and of 
Porta are merely plates of this mucilaginous secretion. 


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Batelli, Andrea. Di una partiedlariti nell’ integumento dell Aphrophora 
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Blankaart, Steph. Sechouburg der Rupsen, Wormen, Maden en vliegende 
Dierkens. Amsterdam. 1688. 

Berlese, Antonio. Gli Insetti. Fasce. 18, pp. 539-540, Milano. 1907. 
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_ Paris. 1900. 

, Joh. Leonh. Beschreibung von allerlei Insecten in Teutschland. 
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Gruner, Max. Biologische Untersuchungen an Schaumcikaden. Berlin. 
1 


Morse, E. SB UA ta eA Insect. Pop. Sci. Mon., pp. 23-29, New 
York, N. Y. 1900 

Mouffet, Tho. The Theater of Insects. London. 1658. 

orta, Antonio. Ricerche sull’ Aphrophora spumaria L. Milano, Rend. 

Ist. lomb., 2. Serie, Vol. 33, pp. 920-928. 1900. 

Porta, Antonio. La- ne della spuma nella Aphrophora. Monit. 
zool. ital., Firenze, Vol. XII, pp. 57-60. 1901. 

s printannieres. Histoire de 1’Academie royale des 

Sciences, Paris, pp. 124-127. 1705. 

i insectorum; opus posthumum. London. 1710. 

_ Uhler, P. R. Hemiptera; Natural History of Arthropods; Standard nat. 

History. Boston. 1884. 

Wheeler, M. Uber driisenartige Gebilde in 1. Abdominal Segment der 

: Hemipteren-Embryonen. Zool. anz., Vol. XII, pp. 594-600. 


SHORTER ARTICLES AND CORRESPONDENCE 
PECULIAR ABNORMAL TEETH IN A JACK-RABBIT 


About ten years ago I saw a curious malformation in the skull 
of a wood-chuck; the upper and lower incisors In some way 
missed coming in contact with each other in the usual way and 
had grown up and down through the skull and lower jaw, to 
wind and twist about above and below completely locking the 
jaws together. This animal was killed by a hunter near 
Waverly, N. Y., and is now in the Museum of Cornell University. 

Since examining this first one, I have seen and heard of a 
number of similar malformations and in all cases the teeth of 
the upper and lower jaws grew more or less irregularly dorsally 
and ventrally. 

A year ago at Claremont, Cal., another peculiar condition was 
brought to my attention in the skull of a young jack-rabbit 
(Figs. 1 and 2). In this skull the teeth are most remarkable 


Fig. 1. Skull and one half of Fie. 2. Skull from below and 


the lower jaw of a young jack- lower jaw from above of a young 
rabbit with unusual incisors. About jack-rabbit with unusual incisors. 
half natural size. About half natural size. 


in the lower jaw, here the two incisors have grown nearly 
straight out some distance and are only slightly curved and 
twisted upon each other. In the upper jaw the incisors are not 
so long and only twisted at the tips. 
WILLIAM A. Hinton. 
POMONA COLLEGE, CLAREMONT, CAL. 
June, 1908. 
799 


NOTES AND LITERATURE 
ICHTHYOLOGY 


Ichthyological Notes.—In the Proceedings of the United States 
National Museum, Volume 33, 1908, Jordan and Richardson give 
an elaborate review of the Flat-heads and Gurnards of Japan. 
In a personal letter, Mr. C. T. Regan, of the British Museum, 
makes one or two corrections in this paper, which may be noted 
here. The species called Hoplichthys langsdorfii by Jordan and 
Richardson is, according to Mr. Regan, a distinct species, not 
identical with the original langsdorfii of C. and V. The 
species called Hoplichthys langsdorfii by Jordan and Richardson 
may therefore receive a new name, ‘‘ Hoplichthys regani Jordan | 
and Richardson.’’ The species called Lepidotrigla microptera 
is, according to Mr. Regan, distinct from the original type of 
that species, which is from Shanghai. The Japanese species 
should, therefore, stand as Lepidotrigla strauchi Steindachner. 

In the same Proceedings, the same authors give an account 
of a small collection of fishes from the Province of Echigo, in 
northwestern Japan, obtained by a local naturalist, Masao 
Nakamura. Besides the three new species in this paper, the 
present writer has since received from Mr. Nakamura two other 
species never before taken in Japan, and which may be recorded 
here. These are Podothecus sturioides Guichenot, and Dasy- 
cottus setiger Bean. 

In the same Proceedings, Eigenmann and Bean describe a col- 
lection of fishes from the Amazon River obtained by Professor 
J. B. Steere. 

In the same Proceedings Mr. B. A. Bean discusses the for- 
gotten genus Ctenolucius, a pike-like characin from Colombia. 

In the same Proceedings Professor John O. Snyder describes 
a new sucker from the Santa Ana River, at Riverside, California, 
under the name of Pantosteus Santa Ane. 

In the Smithsonian Miscellaneous Collections, Volume 48, Mr. 
Barton A. Bean gives the history of the whale shark, Rhinodon 
typicus. The proper date of this genus is 1829. 

In the Smithsonian Miscellaneous Collections, Volume 52, 

800 


No. 504] NOTES AND LITERATURE 801 


Jordan and Branner give an elaborate account of the fossil fishes 
of the eretaceous beds of Ceará, Brazil, these specimens being 
obtained from the Serra do Araripe, the locality from which 
specimens had previously been obtained by Spix, by Agassiz 
and by collectors for the British Museum. These specimens 
are found in concretions of fine clay, and some of them are 
found to be beautifully preserved when these concretions are 
opened. In one species, Calamopleurus cylindricus, the black 
pigment at the base of each scale forming stripes along the side 
of the body is perfectly preserved, and the eye-ball is also well 
shown. In this collection Jordan and Branner find eleven dif- 
ferent species, including all of those described by Agassiz, and 
including three new genera, Tharrhias, Enneles and Cearana. 
Most of the species belong to the family of Elopide, which 
represents one of the earlier types of bony fishes. 

In the Occasional Papers of the Boston Society of Natural 
History, Volume 7, 1908, Mr. William C. Kendall gives a very 
useful list of the fishes of New England, and the localities from 
which each species has been recorded. The list contains 341 
species, a number of these being estrays from the south brought 
northward by the Gulf Stream. 

In the Memoirs of the Carnegie Museum, Volume 4, 1908, 
Jordan and Snyder describe and figure three new carangoid 
fishes from Formosa. One of these, Ulua richardsoni, consti- 
tutes a distinct genus, separated from Caranx by the extraor- 
dinary development of the gill-rakers, which cause the mouth 
to appear as if ‘‘full of feathers,” much as in the genus of 
mackerels called Rastrelliger. 

In the Journal of the College of Science of the Imperial Uni- 
versity of Tokyo, Volume 23, 1908, Mr. Shigeho Tanaka gives a 
list of sixteen species new to the fauna of Japan, all but one 
of them new to science. Among these species is the new genus, 
Owstonia, of the family of Opisthognathide. Most remarkable 
of the discoveries is the addition of two more new species of 
Chimera to the Japanese fauna. This makes eight species of 
Chimera in all, described from Japan, all of them discovered 
since the year 1900. 

In the Annotationes Zoologice Japonenses, Volume 6, 1908, 
Mr. Tanaka describes the fishes, sixty-three in number, collected 
by Professor Ijima in Sakhalin. Of the fauna of this region— 


802 THE AMERICAN NATURALIST [Vou. XLII 


that of northern Japan—two new species, both of Porocottus, 
are described and figured. 

In the Proceedings of the Academy of Natural Science of 
Philadelphia, Volume 59, 1908, Mr. Henry W. Fowler describes 
a collection of fishes from Melbourne. Among these is a new 
Chimera, Hydrolagus waitei, for which a new subgenus, 
Psychichthys, is proposed. In the course of the paper a number 
of new subgenera are added to the already long list of genera 
of doubtful value. 

In the same Proceedings Mr. Fowler has a catalogue of the 
lancelets and lampreys contained in the collection of the Acad- 
emy of Sciences. A new genus and species, Oceanomyzon 
wilsoni, is described from the open Atlantic. Lampetra epytera 
(Abbott) is said to be identical with Lampetra wilderi, the 
common black lamprey of Cayuga Lake. The name Lampetra 
cepytera has priority. 

In the same Proceedings for 1906 Mr. Fowler describes new 
and little-known percoid fishes. He uses the name Dules in 
place of Kuhlia, and describes a new subgenus, Boulengerina, 
for Kuhlia malo, this group being based on the numerous gill- 
rakers. Some changes of nomenclature are made, based on the 
adoption of the rule that the first species mentioned in any 
genus shall become the type. This rule, which would have been 
just if it could have been originated earlier, will not be accepted 
by naturalists, as the International Congress has taken the view 
that in case a type is not fixed by the original author the writer 
following has a right to fix it, and once established it shall not 
be changed for any reason. The subgenus Astrapogon is sug- 
gested for Apogonichthys stellatus, characterized by the very 
long ventrals. 

In the same Proceedings Mr. Fowler discusses the hetero- 
gnathous fishes in the museum at Philadelphia, with descriptions 
and figures of many of these. Several new species are de- 
scribed, and a number of new generic and subgeneric names 
suggested 

These papers are subjected to critical review in the AMERICAN 
Narurauist, Volume 41, by Dr. C. H. Eigenmann. Dr. Eigen- 
mann claims that many of the new names proposed by Mr. 
Fowler are quite unnecessary. He says: 


We must feel grateful to Dr. Fowler for his labor. But it is to be 


No. 504] NOTES AND LITERATURE 803 


hoped that in the future he will be more conservative in adding names _ 
to the science of ichthyology. The valid names do not compensate for 
the work imposed on some one else to separate them from the synonyms. 

In the same Proceedings for 1907 Mr. Fowler catalogues the 
serranoid fishes in the collection at Philadelphia. He substitutes 
the name ‘‘Serranus’’ for ‘‘ Epinephelus,’’ for reasons that would 
be hardly valid even if we adopted the first-species rule, as 
Cuvier states that his name Serranus comes from the French 
name Serran, and that the species on which it is based are com- 
mon in the Mediterranean. In other words, his actual type, 
although not the species first mentioned, by name, is Serranus 
cabrilla. The subgeneric Chrysoperea is introduced for Morone 
interrupta. . 

Serranus pheostigmeus is a species of Epinephelus described 
as new from Hawaii. A new species of Alphestes is described 
as Epinephelus lightfooti from San Domingo. 

Eudulus is proposed as a new name for the genus Dules, which 
Mr. Fowler regards as preoccupied by Dulus, a genus of birds. 
Mr. Fowler shows that the number of the ‘‘Régne Animal,” 
referring to these fishes, is prior in date to that number of the 
‘‘Histoire Naturelle des Poissons’’ referring to the same species. 
Mr. Fowler also finds that the name malo of Valenciennes is 
older than that of mato given to the same fish—perhaps by 
typographical error. 

The subgenerie name Callidulus is proposed for Centropristis 
or Eudulus subligarius. 

In the Annals of the Carnegie Museum, Dr. Carl H. Eigen- 
mann records a large collection of fishes from Paraguay. In 
all, two hundred and fifty-four species are known from that river 
basin. Ninety-five of these are peculiar to the Paraguay. One 
hundred and thirty-two are found also in the Amazon. The 
amazingly rich fish fauna of tropical America comprises one 
tenth of all known fishes. 

In the Proceedings of the Washington Academy of Sciences, 
Volume 8, 1907, Dr. Eigemann describes a collection of fishes 
from Buenos Aires obtained by Professor W. B. Scott. 

In the Proceedings of the Field Columbian Museum, Volume 
7, 1907, Dr. S. E. Meek gives notes on fresh-water fishes obtained 
by him and others from Mexico and Central America. Cich- 
lasoma milleri is described as new from Guatemala, and also 
Rhamdia regani, Platypecilus tropicus and Pecilia tenuis. 


804 THE AMERICAN NATURALIST [Vou. XLII 


In the same Proceedings, Volume 7, 1908, Dr. Meek gives an 
interesting account of the ‘‘ Zoology of the Lakes of Guatemala.’’ 

In Science, Volume 27, 1908, Professor J. O. Snyder discusses 
the region of the fauna of the Russian River in California, show- 
ing that these fishes were derived from the Sacramento River 
by a process of stream-robbing, by which through erosion the 
Russian River Valley incorporated small streams from tribu- 
taries of Clear Lake, which drains into the Sacramento. 

In the Bulletin of Agriculture of the Dutch East Indies, 

Volume 8, 1907, Dr. P. N. van Kampen describes two of the 
mackerel found on the coast of Java. These descriptions are 
useful, but the synonmy given perhaps needs verification. 
These mackerel apparently belong to the genus Rastrelliger, 
distinguished from Scomber by the very great number of gill- 
rakers, recently described by Jordan and Starks. 
In the Annuaire of the Museum of Sciences of St. Petersburg, 
Volume 12, 1907, Dr. L. Berg describes the grayling of Siberia, 
with a comparative account of their relation to other salmonine. 
The species known as Brachymystaz obtusirostris from Siberia 
is made the type of a new genus, Salmothymus, differing from 
Brachymystax in having the vomer prolonged, with two rows 
of teeth, as in Salmo. The subgenus Thymalloides is proposed 
for Thymallus arcticus, this group species including also all the 
American grayling, the name Thymallus being restricted to 
T. thymallus, the grayling of Europe, which does not occur to 
the eastward of the Ural Mountains. Three species of Hucho 
are recognized, H. hucho in the Danube, H. taimen in Siberia 
and H. perryi in Japan. The genus Phylogephyra is recognized 
for Thymallus brevirostris, or altaica, of Siberia. This is dis- 
tinguished by the larger mouth and larger and more numerous 
teeth, which are present on the head of the vomer and on the 
tongue. 

Dr. Theodor von Kawraysky has published an elaborate ac- 
count in Russian and in German of the sturgeons of the Cau- 
casus, with lists of other fishes taken in the same region. 

_ In the Memoirs of the Museum of Comparative Zoology of 
Harvard Dr. Charles H. Gilbert gives an account of the lantern 
fishes collected by the Albatross in the South Seas. The species 
obtained are carefully described, and their synonymy very fully 
worked out. Several new species are contained in the collection. 


No. 504] NOTES AND LITERATURE 805 


The genus Zalarges of Jordan and Williams is identified with 
Vinciguerria. 

In the Bulletin of the Museum of Comparative Zoology for 
February, 1908, Mr. Samuel Garman describes a number of new 
sharks and skates. The genus Aëtomylæus is proposed for 
Myliobatis maculatus. Raia kincaidii is described as new from 
Friday Harbor, Puget Sound, and Chimæra barbouri from 
Aomori, Japan. 

In the University of Colorado Studies, Volume 5, No. 3, Pro- 
fessor T. D. A. Cockerell gives a list of the fishes of the Rocky 
Mountains, with useful notes on geographical distribution, and 
references to the fossil as well as to the living forms recorded 
from that region. Brief keys are given, enabling local students 
to identify specimens in hand. i 

In the Zoologischen Anzeiger, Volume 32, 1908, Dr. Franz 
and Dr. Stechow describe an interesting case of symbiosis be- 
tween the fish, Minous adamsii, a form of scorpion-fish, and the 
hydroid polyp Podocoryne from Sagami. 

In the Sitzungsberichte of the Academy of Vienna for 1908 
Dr. Steindachner describes two new fishes from Brazil. 

In the Transactions of the Wisconsin Academy of Sciences, 
Volume 16, 1908, George Wagner gives a useful list of the fishes 
of Lake Pepin, forty-four species being recorded. 

In the Natuurkundig Tijdschrift of the Dutch East Indies, 
Volume 67, 1908, Dr. P. N. van Kampen has an interesting 
series of notes on the spear fishes found in Java. The common 
species he identifies as Tetrapturus brevirostris. T. mazara of 
Japan may be the same species. 

In the Bulletin of the Société Nationale d’Acclimatation of 
France Dr. Pellegrin gives a review of the fresh-water fishes of 
Madagascar, with discussions of the economic value of each 
species. 

Among the papers left at the death of Professor Karl Ernst 
von Baer is a biography of Cuvier which had never been pub- 
lished, and which is exceedingly interesting as a contemporary 
account of one of the greatest of naturalists and written by one 
of his ablest contemporaries. It is published in the Annales 
des Sciences Naturelles, in Paris, by Professor Ludwig Stieda, 
of Königsberg. 

In the Archivos do Museu Nacional of Brazil, Volume 4, 1907. 
Dr. Alipio de Miranda Ribeiro continues his catalogue of the 


806 THE AMERICAN NATURALIST [Vou. XLII 


fishes of Brazil, this volume treating of the sharks, with de- 
scriptions of each species, and analytical keys. The memoir is 
beautifully printed and illustrated by photographs of very many 
of the species. The synonymy is given in an appendix, and the 
nomenclature is in general in accord with the rules adopted by 
American naturalists and by the International Congress. 

Dr. C. T. Regan continues the catalogue of the fishes of Cen- 
tral America. Brycon guatemalensis is described as new from 
Guatemala. Tetragonopterus macrophthalmus is described 
from southern Mexico, as is also T. angustifrons. Mr. Regan 
recognizes a number of additional species of Lepidosteus. It 
is very desirable that the garpikes of the United States should 
receive a critical review. It is quite possible that more species 
really exist than the three which have been recognized by Jordan 
and Evermann. Mr. Regan proposes the name Conorhynch- 
ichthys in place of Conorhynchus, the latter name being pre- 
occupied. This paper completes the study of the fishes in the 
fauna of Central America. It is a very important and very well 
executed piece of systematic work. 

In the Transactions of the Linnean Society of London, Mr. 
Regan gives an elaborate account of the fishes collected by the 
Perey Sladen Trust Expedition to the Indian Ocean in 1905, 
under the leadership of Mr. J. Stanley Gardiner. One hundred 
and eighty-five species were obtained, many of them new to 
science, these being figured in the present volume. Among other 
interesting forms are six new species of the genus Champsodon. 

Under the head of ‘‘ Edible Fishes of New South Wales,’’ Mr. 
David G. Stead, naturalist of the Board of Fisheries at Sydney, 
gives a popular account of the fishes which appear in the 
markets of Sydney, illustrated by numerous photographs. This 
interesting and valuable report is accompanied by a map of the 
state of New South Wales. 

Under the title of ‘‘Trout Fishing in New South Wales,” Mr. 
Charles Thackeray, of Sydney, gives an account of the various 
streams in the state, in which trout from Europe and the United 
States have been introduced. The little volume is extremely 
valuable to Australian anglers, and is also interesting as showing 
the remarkable success which has attended the introduction of 
the California rainbow trout in the Antipodes. 

Under the head of ‘‘Guide to the Gallery of Fishes in the 
‘Department of Zoology of the British Museum (Natural His- 


No. 504] NOTES AND LITERATURE 807 


tory),’’ the trustees of the British Museum have published a 
book of two hundred and nine pages giving an account of the 
principal kinds of fishes, the characteristics of the different 
families, and in general an outline of the classification adopted 
in the distribution of the species in the museum. A number 
of figures are given, some of living and some of extinct species. 

In the Transactions of the Royal Society of Canada Dr. J. F. 
Whiteaves continues his account of the fossil fishes of the 
Devonian Rocks of Canada, with descriptions of numerous 
species and restoration of others. Most interesting is the extraor- 
dinary Bothriolepis canadensis, restored in accordance with 
investigations of Professor Patten. This form has many char- 
acteristics of arthropod animals. With its head, eyes and coat 
of mail, suggesting something like a horseshoe crab, it is hard 
to believe that it is a fish. On the other hand, it is hard to 
believe that the tail, provided with what seems to be a rayed 
dorsal fin, can belong to any kind of ecrab-like animal. 

In the Sitzungsberichte of the Academy at Vienna, Volume 
116, 1907, Dr. Viktor Pietschmann describes two new sharks 
from Sagami Bay, Japan, Centrophorus steindachneri and 
Etmopterus frontimaculatus. 

In the same journal for 1908 Dr. Steindachner describes 
fishes from South America, and also a loach from Formosa, the 
latter called Homaloptera formosanum. 

In the same journal, Dr. Steindachner describes a new genus 
of characins called ‘‘Joinvillea.’’ 

In the same journal he describes also other species of South 
American river fishes. 

In the Annals and Magazine of Natural History, 1908, Mr. 
Regan describes new fresh-water fishes from Japan and Formosa. 

In the same journal Mr. Regan describes also new fresh-water 
fishes from New Guinea. 

In the Proceedings of the Zoological Society of London Mr. 
Regan describes a number of new species from Corea. 

In the Annals of the Natal Government Museum Mr. Regan 
gives a list of marine fishes from South Africa, nine of them 
being described as new. Mr. Regan gives also a useful analysis 
of the eight species recognized by him in the genus Squatina. 
Of these S. japonica and nebulosa are found in Japan, and S. 
californica off the coast of California. 

In the Annals and Magazine of Natural History, 1908, Mr: 


808 THE AMERICAN NATURALIST [Vou. XLII 


Regan gives a synopsis of the sharks, Scylliorhinide. To 
Seylliorhinus are referred the species of Catulus, Cephaloscyl- 
lium and Halelurus. The genus Parmaturus is regarded as 
identical with Pristiurus. 

In the same journal, Mr. Regan has a review of the sharks of 
the family of Squalide. In this the name Spinax is preferred 
to Etmopterus, because of the inaccuracy of Rafinesque’s de- 
scription. Frontimaculatus of Japan is regarded as identical 
with the European E. pusillus. The genus Zameus is regarded 
as identical with Scymnodon. Deania and Lepidorhinus are 
placed in synonymy with Centrophorus. Deania eglantina from 
Japan is regarded as identical with the European Centrophorus 
calceus. The name Scymnorhinus is preferred to Dalatias, 
because of the very inaccurate description of the genus of 
Rafinesque. 

In the same journal Mr. Regan describes new loricaroid fishes 
from South America. 

In the same journal Mr. Regan gives a synopsis of the ces- 
traciont sharks. He regards the name Heterodontus as pre- 
occupied by Heterodon, thus accepting the latter name Ces- 
tracion. He accepts the genus Gyropleurodus as distinct from 
Heterodontus. 

In the same journal Mr. Regan describes Cichlosoma laure as 
a new species from Tampico. Enneanectes carminalis was found 
at Swan Island, near Honduras—a little blenny hitherto known 
only from Mazatlan. 

In the same journal Mr. Regan describes a hybrid between 
the bream and the rudd, with notes on other hybrids among the 
European cyprinoid fishes. 

In the Proceedings of the United States National Museum for 
1908, Jordan and Dickerson give an account of fishes obtained by 
Dr. Jordan at Fiji. The fauna of the islands is essentially like 
that of Samoa, the physical nature of the reefs being closely 
identical in the two regions; but even in this small collection 
are several species which are distinctively characteristic of the 
New Guinea waters. The deep-bodied mackerel of the Pacific 
are separated from Scomber to form a new genus, Rastrelliger, 
differing especially in the very long gill-rakers, the mouth looking 
as if ‘‘full of feathers.’ With this are other characteristics, 


- oS the teeth being very minute and there being none on the roof 


No. 504] NOTES AND LITERATURE 809 


of the mouth, and there are certain peculiarities in the structure 
of the bones connecting with the tongue. 

In the ‘‘ Actes de la Société Linnéenne de Bordeaux,’’ 1907, 
Dr. Pellegrin describes a collection of fishes taken on the west 
coast of Africa, with useful notes as to their distribution. The 
nomenclature adopted is rather outworn, and not much notice 
is taken of questions of priority of names. The illustrations are 
photographs, very obscurely printed. It may be noted that 
Sardinella aurita, type of the genus Sardinella, is a large-scaled 
herring of the group called Harengula. The name Sardinella 
has priority over Harengula, and the name Sardinia must be 
used for the true sardine. 

In the Comptes rendus of the French Association for the Ad- 
vancement of Science, Dr. Pellegrin gives an interesting account 
of the incubation of the eggs of marine ecat-fishes. The male 
takes care of the egg and the young, taking into the mouth from 
ten to twenty eggs. The young are retained in the mouth until 
the yolksae is absorbed. During this period of incubation the 
male does not feed. 

In the Annals of the New York Academy of Sciences, Dr. R. 
W. Tower discusses the production of sound in scienoid and 
other fishes. In this very lucid paper it is shown that these 
fishes ‘‘known as drums, croakers or roneadores’’ have specifie 
drumming muscles, superficially attached to the swim-bladder. 
For this muscle Dr. Tower proposes the name musculus sonificus. 
The cause of the drumming or grunting noise is the contraction 
of this muscle, which produces a vibration of the abdominal 
walls and organs, especially the swim-bladder. In the sciænoid 
fish, the mechanism is adapted to the production of rapidly re- 
peated sounds or rolls. In other fishes which grunt, as the sea- 
robin and toadfish, the muscles are intrinsically connected with 
the swim-bladder, and are known as intrinsic muscles. | These 
muscles produce a vibration in the walls of the swim-bladder 
which may be repeated at intervals. Dr. Tower gives a number 
of valuable plates showing the structure of these organs, and 
also a graphic record of the sounds produced. 

In the Proceedings of the Biological Society of Washington, 
H. Walton Clark describes the Plankton of the Lakes of Guate- 
mala. 

In the Bulletin of the American Museum of Natural History, 
Volume 25, Dr. L. Hussakof gives a catalogue of the fossil fishes 


810 THE AMERICAN NATURALIST (Vou. XLII 


contained in the American Museum, with figures of many of 
the fragments. 

In the Biological Bulletin, Volume 13, Mr. Fernandus Payne 
describes the effect of light on the blind fish of the Mammoth 
Cave. In this species the fishes turn away from the light. The 
young are more sensitive than the adult. The young deprived 
of eyes are as sensitive as those which have them. They seem 
to be equally sensitive on all parts of the body, and more sensi- 
tive to intense light. They seek the dark without regard to the 
direction of the rays. 

In the Bureau of Fisheries, document 622, Mr. Irving A. Field 
discusses unutilized fishes, and methods by which these waste 
species can be rendered of economic service. 

In the American Journal of Anatomy, Mr. William F. Allen 
describes the blood-vessels in the tail of the garpike, this paper 
being a continuation of his series of studies of the circulatory 
system in different fishes. 

In the Procedings of the American Academy of Arts and 
Sciences, Dr. G. H. Parker describes the sensory reactions of the 
lancelet. This creature possesses in potentia the sense organs 
of the vertebrate. It is simple in structure, containing fore- 
runners of the lateral-line organs, the ear, the temperature or- 
gans, and doubtless the forerunners of the rod- and cone-cells 
of the vertebrate retina. It is only slightly sensitive to light, 
but is sensitive to temperature and to sound. 

In the Journal of Experimental Zoology, Mr. H. H. Newman 
describes the relation of the hybrids of Fundulus majalis with 
Fundulus heteroclitus to problems in heredity. The writer 
thinks that the study of development and heredity are identical, 
except that the latter is comparative. No two organisms start 
out from identical germ cells, nor do they ever develop under 
identical conditions. Instead of a fixity of relationship between 
pure strains and hybrids, there is constant flux. 

In the Proceedings of the United States National Museum, 
Volume 33, for 1907, Seale and Bean describe the fishes collected 
in the Philippines by Major Mearns, with seven new species. 

-~ In the Smithsonian Miscellaneous Contributions, V, 1908, Mr. 
W. C. Kendall shows that the unrecognized species of whitefish 
from Saskatchewan River called Coregonus angusticeps by 
Valenciennes is the chub, Platygobio gracilis. 

In the same Contributions, Dr. Jordan shows the identity of 


No. 504] NOTES AND LITERATURE 811 


the fossil stickleback from Nevada, Gasterosteus leptosomus 
Hay, with Merriamella doryssa. The species stands as Gas- 
terosteus doryssus. 

In the same Contributions, Dr. Gill gives an account of the 
habits of the miller’s thumbs or blobs. He shows that Uranidea 
ean not be maintained as a genus distinct from Cottus and that 
the common species must be called Cottus richardsoni, not C. 
ictalops. 

In the Transactions of the Wisconsin Academy of Science, 
Mr. R. H. Johnson discusses the variations in number and size 
of the pylone cxea in Sun-fishes. In each species a variation 
of two or three was found. Thus in species as the rock bass, 
having on the average eight ceca, the number ranges from six 
to nine. In the calico bass, with nine, the number ranges from 
eight to eleven. DAVID STARR JORDAN. 


THE INHERITANCE OF SEX IN HIGHER PLANTS 


Digest of Professor ©. Correns’s Memoir !—It is stated in the 
preface that there is given here a more detailed reiteration of 
a report made September 18, 1907, to the united sections for 
zoology and botany of the German Naturalists in Dresden. 
Experiments in cross-breeding closely related species of plants 
of different sexual type, carried on since 1900, led to such re- 
markable results that an account was long withheld. When a 
repetition of experiments yielded like results, and a reconsidera- 
tion of the deductions made revealed no flaws, conclusions were 
announced. For the plants examined the results are regarded 
decisive; but their wider application must be ascertained by 
further investigation. 

Correns refrains from an historical review of the literature 
and attempts merely to present some new facts and relate them 
to previous facts. He does not wish, nor does he claim to be 
able, to construct a new theory regarding the nature of sex. He 
believes that there is much in common between his results and 
those reported by E. B. Wilson for Hemiptera. Finally he ex- 
plains that by ‘‘anlage’’ of an organ as used in his paper he does 

16‘ Die Bestimmung und Vererbung des Geschlechtes nach neuen Ver- 
suchen mit hoheren Pflanzen.’’ Abstract presented before a recent ‘meeting 
of the Medico-Biological Journal Club of the University of Virginia, by 
H. E. Jordan, adjunct professor of anatomy. 


812 THE AMERICAN NATURALIST (Von: XLII 


not mean the earliest visible developmental stage, but the repre- 
sentative of the organ in the germ-plasm. 

In the introduction Correns notes that the present opinions 
concerning sex-determination are built largely upon the results 
(chiefly negative) obtained from attempts to control or alter 
sex, and upon observations on parthenogenetically developing 
eggs; in part also upon morphological and statistical data. The 
main object of his paper is to describe attempts to discover by 
experimental methods, whether the germ-cells have from the 
beginning a fixed sex-tendeney and if so of what kind, and what 
role fertilization plays in sex-determination. He regards these 
as fundamental questions which must be answered before one 
can judge intelligently of the effects of unusual external in- 
fluences. For the elucidation of these same questions he believes 
we are largely limited to the plants, particularly the flowering 
plants, due to the more favorable material they offer for experi- 
mentation. 

In essence, the fertilization process in plants and animals is 
the same: two germ-cells unite to form a new organism. Botan- 
ists are to-day convinced of the polyphyletie origin of plants 
and, while it is possible, it is not very probable that sex-deter- 
mination and sex-inheritance were arrived at in the different 
groups by the same path of differentiation. A question to be 
settled by further work, therefore, is whether the principles 
determined for the particular flowering plants under considera- 
tion apply also to other groups of plants, and also to animals. 

Already in mosses are found a sharply expressed differentia- 
tion of germ-cells into egg-cells and sperm-cells, and this special- 
ization is retained with various slight modifications throughout 
all the higher groups. In phylogenetically lower forms than the 
mosses the gametes are all alike (swarm spores). Chance or 
chemotactic influences may bring such into contact and subse- 
quent union, or they may germinate asexually as in Protosiphon 
according to Klebs. Externally all are alike. Sometimes, as 
observed by Klebs in Chlorocytrium, cells from the same mother- 

cell may copulate. The question arises whether they are in- 
trinsically alike or whether they consist of two classes, + and —, 
as Blakeslee proposes. In the first case every gamete may copu- 
late with any other and there is sexuality but no sex-differentia- 
tion. In the second case only + and — gametes can copulate 
~ , and sex-differentiation Stam, the foundation for further dif- 


No. 504] NOTES AND LITERATURE 813 


ferentiation into egg and sperm not now externally visible. 
Further development may proceed along different paths. Dif- 
ferentiation may arise between individuals, + and — gametes 
being then localized in separate members, and the gametes of 
these same plants may be mutually incapable of union so that 
only gametes of different plants can copulate. These are here 
+ and — individuals, but the gametes may give no external 
evidence of a difference. This is the case in Dasycladus accord- 
ing to Berthold and in Ulothrix according to Dodel. Or there 
may arise differences between the gametes, the one becoming, by 
the surrender of motility and the assumption of nutritive func- 
tions, an egg cell; the other, remaining small and retaining 
motility, becoming a spermatozoon. Thus hidden differences 
between -+ and — germ-cells become conspicuous and there 
appear ‘‘female’’ gametes and ‘‘male’’ gametes. When the 
specialized gametes are combined in the same plant it becomes 
hermaphrodite or monoecious; when separted, dioecious forms 
appear. 

Correns lays emphasis on several points: (1) That the differ- 
entiation of gametes into egg and sperm has nothing to do with 
the union of the two germ-cells for the production of a new 
individual; or, in other words, that the externally visible differ- 
ences between egg and sperm need have no connection with the 
process of fertilization; (2) individuals may be differentiated 
into males and females without an evident external mark o 
differentiation either in the individuals themselves or in their 
germ-cells. The various differential characters of eggs and 
sperm-cells and all other visible differences between male and 
female individuals reveal only their different nature, but do not 
touch the essence of sex itself. Interesting confirmatory obser- 
vations in this connection are those of Blakeslee on Mucorinee. 

Originally there is present only the ‘‘determination’’ in the 
germ-cells which renders possible the union of some pairs of 
germ-cells and prevents the union of other pairs. All else is 
of a secondary character. With few exceptions the higher ani- 
mals are unisexual. Among the higher plants many different 
sexual types occur. Neglecting transition conditions, the main 
types are hermaphrodite forms where stamens and pistils are 
united in the same flower; bisexual or monoecious forms, where 
pistils and stamens are separated into female and male flowers; 
unisexual or dioecious forms, where the male and female flowers 


814 THE AMERICAN NATURALIST [Vou XLII 


are borne by different individuals. By far the larger majority 
of flowering plants have hermaphrodite flowers. Separation of 
sexual organs on different flowers or different individuals ap- 
pears here and there as characteristic of entire families, and 
relatively often as a specific character, or sometimes only as a 
variation ; and this in the most distantly related groups. 

Correns entertains no doubt that hermaphroditism is the pri- 
mary type and dioeciousness the derived. He does not regard 
as conclusive the arguments advanced by Coulter and Cham- 
berlain that it is impossible to decide which is the primary con- 
dition since dioeciousness appears in both the quite low and the 
higher groups of flowering plants, being related in the former to 
wind-pollination and in the latter connected with insect-pollina- 
tion. He observes that sex-separation appears also in other 
groups without any relation to the high or low degree of other 
characters. The dioecious condition arises in consequence of 
the physiological or morphological disappearance of one or the 
other set of members of the hermaphrodite condition. The ‘‘de- 
generation’’ of a sexual organ here is really nothing else than an 
arrest at a certain stage in the development of one or the other 
element in the hermaphrodite flower (Hofmeister; Goebel), thus 
producing the monoecious or dioecious conditions. Such change 
naturally does not proceed without an alteration of the idioplasm 
of the species involved; the ‘‘anlagen complex’’ of one element 
must become more or less incapable of development, or latent. 
As far as we know this process follows independently in both 
sexes and, in each, internal and external alterations stand in 
intimate correlation. Male and female flowers of monoecious 
species are of like high development. The female is not a male 
arrested at a lower stage of development. The great differences 
in size and vitality between germ-cells must be regarded as 
adaptations. . 

The main points involved in the problem of this investigation 
concern the method by which sex is determined and the time 
when such determination takes place. Since the embryonic and 
the adult sex-organs contain the anlagen for the characters of 
both sexes, sex-determination has to do with the question as to 
which anlage, male or female, shall develop. These conditions 
demand that the germ-cells have a fixed sex-tendency already 
before their union at fertilization. Correns emphasizes also that 


oo : one must not here think of a separation and distribution of 


No. 504] NOTES AND LITERATURE 815 


anlagen for the sex-characters into separate germ-cells in the 
sense that into one animal wander testes-anlagen (determinants 
of Weismann) and into another ovary-anlagen. This as far as 
we know is not the case. Both germ-cells carry both sets of sex- 
characters, as experiments with hybrids abundantly show. That 
a germ-cell has male or female sex-tendeney means only that the 
male or female anlagen are in condition of capability to develop. 
As to how one anlage in the germ-cells becomes active and the 
other is brought to a latent condition we have no positive knowl- 
edge. 

One may entertain several possibilities respecting the time 
that sex is determined. He may take the position that the germ- 
cells have held from the beginning the tendency to develop into 
one or the other sex—which sex becomes apparent when caused 
to develop by artificial parthenogenesis—and that the tendency 
remains unchanged by fertilization; in other words, that the 
germ-cells are unalterably fixed as to their sex-tendency and thus 
iafependently determine the sex of their offspring pure: ‘‘pro- 
game’’ determination. Either all the sperm or all the eggs are 
so determined or only a part of each. Such predestination is 
commonly ascribed to the egg, and the sperm is thought to be 
without influence. Accordingly, half the eggs must be male and 
half female in tendency. 

The second position ascribes to the germ-cells before fertiliza- 
tion no fixed tendency to develop into a particular sex, and holds 
that only at fertilization is the decision made as to what sex the 
offspring shall have: pure ‘‘syngame’’ determination. 

According to the third position the product of the union of 
the two germ-cells has no fixed sex-tendency. External in- 
fluences determine only during the later stages of development 
what the sex of the offspring shall be: pure ‘‘epigame’’ deter- 
mination. Theoretically an ‘‘epigame’’ alteration of sex must 
be possible, since the embryo contains both sex-anlagen. All 
critical investigations, however, both zoological (O. Schultz) and 
botanical (E. Strasburger), indicate that the means thus far em- 
ployed in attempting to produce an alteration of sex-tendency 
have yielded no significant results respecting the actual separa- 
tion of sex-organs among different individuals. Primarily, at- 
tempts must be made to determine whether the germ-cells of 
unisexual forms have an indifferent sex-tendency or whether 
they have a fixed tendency. If the latter condition prevails, it 


816 THE AMERICAN NATURALIST [Vou. XLII 


is incumbent next to determine what this tendency is. There 
are several possibilities: (1) The germ-cells may have the sex- 
tendency of the plant from which they came, the egg-cells the 
female, the sperm-cells the male; (2) they may have the opposite 
sex-tendency; or (3) some of the eggs may be of one sex-tend- 
ency and a part of the other, and likewise the sperm. A further 
problem arises as to how far fertilization plays a rôle in sex- 
determination, since thus germ-cells of different sex-tendencies 
may unite; and also how far external influences have significance 
in that they can act upon the sex-tendency of the germ-cells 
before fertilization, or at the time of fertilization upon the united 
product, or after fertilization on the embryo. 

Whether a given germ-cell contains a fixed sex-tendency can 
best be ascertained when such a cell can be caused to develop 
without fertilization into a sexually mature individual. Such 
conditions obtain in eases of ‘‘habitual parthenogenesis.’’ The 
facts here at first sight seem to compel acceptance of the position 
that the sperm-cells play no rôle. However, on closer scrutiny 
of the facts, doubts are raised as to the validity of such an in- 
terpretation. One must not forget that generally eggs that de- 
velop parthenogenetically do not undergo a reduction division. 
Correns states that whatever significance one may attach to re- 
duction, he can not regard such eggs as of like nature with those 
that have suffered maturation. In the case of ‘‘habitual par- 
thenogenesis’’ one deals with phenomena of adaptation. Such 
adaptation may enable an egg to develop without fertilization 
even though this capacity depends only on the suspension of a 
check, which otherwise, through the intervention of a male germ- 
cell, could exert its influence. In similar manner the sex-tend- 
ency also may be influenced. Natural and artificial partheno- 
genesis yield an indication of the sex-tendency only of the egg. 
“*Ephebogenetic’’ development of sperm-cells, theoretically pos- 
sible, but practically thus far beset with insuperable difficulties, 
is urgently required. Merogony furnishes no positive results 
until we know definitely the rôle of cytoplasm, as distinct from 
karyoplasm, in heredity. 

Correns turns into other fields which seem to lead farther 
than experiments with artificial parthenogenesis, namely, hybrid- 
ization. The controlling idea of Correns’s investigation is the 
following: The egg-cells of a dicecious form whose sex-tendency 


No. 504] NOTES AND LITERATURE 817 


we desire to ascertain, is commonly fertilized by a sperm-cell 
of the same species. The sex-tendency of both gametes is un- 
known. On the other hand, the sex of the offspring resulting 
from the union of the gametes becomes obvious. In other words 
by the interaction (in union) of two unknown quantities, Y and 
Y, i. e., the sex-tendencies of the two gametes, there results an 
organism of known sex; or «+ y= sex of organism. Could 
the value of either x or y be ascertained the equation could be 
solved and the value of the other unknown quantity determined. 
These yalues Correns obtains in the case of the germ-cells of 
two favorable, nearly related, species of plants one of which is 
hermaphrodite and the other diecious. The above figure is not 
quite accurate, as Correns point out, since a solution of the 
equation is possible only when the unknown sex-tendency of the 
germ-cell of dicecious type, as over against the known sex-tend- 
ency of the hermaphrodite germ-cell, is so strong as to wholly or 
almost entirely prevent the development of the latter or to 
greatly suppress it. The conditions are fully met in those cases 
where the sperm-cell of a white-flowering pea by fertilization 
makes possible the development of the egg-cell of a red-flowering 
pea, so that a red-flowering plant results without showing a trace 
of the white factor of the sperm. Thus is obtained the effect of 
artificial parthenogenesis, not only on the egg cell but also on 
the sperm-cell. 

The germ-cells of hermaphrodite forms carry the hermaph- 
rodite sex-tendency and give rise only to hermaphrodite forms. 
Correns does not regard a hermaphrodite individual as a 
‘c mosaic”? derived from the union of a germ-cell of male tend- 
ency with one of female tendency. However, they must contain 
the anlagen of such a mosaic. Hermaphrodite germ-cells contain 
only the hermaphrodite sex-tendency both in the egg-cells and 
in the sperm-cells. Likewise for monecious forms, where on the 
same individual two kinds of sexual flowers appear, male and 
female, the same position must be taken; i. e., that both kinds 
of germ-cells, eggs and sperm, carry the same tendency, namely, 
the tendency to develop into monecious forms. Each germ-cell 
thus carries over not the sex of the flower from which it came, 
but that of the entire plant on which the sexual flowers appeared. 

There remains no doubt concerning the monecious tendency 
of the germ-cells of monecious plants. Correns cites in further 


818 THE AMERICAN NATURALIST [Vou. XLII 


support of this position the case of Dimorphotheca pluvialis, a 
‘*trimoncecious’’ form where flowers of three kinds, male, female 
and hermaphrodite, occur in the same head. Since we have 
here two kinds of sperm-cells (pollen), one from the hermaph- 
rodite flower and one from the male flower, and also two kinds 
of eggs, embryos can arise in four different ways. If the germ- 
cells had different sex-tendencies after they are built into a 
male, a hermaphrodite, or a female flower, four kinds of offspring 
would arise. All the seed, however, produce the same kind of 
offspring, i. e., trimonecious forms. Therefore all the germ- 
cells of Dimorphotheca must bear the tendency again to give 
origin to trimonecious plants. It may be said then, that all 
germ-cells of a hermaphrodite plant have the tendency again 
to develop into hermaphrodite plants, whether they be found in 
stamens or pistils. All germ-cells of moncecious forms have the 
tendency again to produce monecious forms whether they arise 
in male or female flowers. We know, then, the tendency of the 
germ-cells in hermaphrodite and monecious types and we can 
employ these known quantities to ascertain by cross-breeding the 
unknown tendency of the germ-cells of unisexual plants. 

In the first three experiments Dr. Correns employed two 
species of Bryonia, a genus of the Cucurbitacer, growing wild in 
central Europe. Bryonia alba bears a black fruit and is 
monecious. Bryonia dioica bears a red fruit and is dicecious. 
In the first experiment (A) he pollinated the pistils (egg-cells) 
of Bryonia dioica with the pollen of Bryonia alba. He obtained 
eleven hybrid offspring from the seed, all female plants and 
perfectly sterile. These results disclose the following facts: 
(1) That moneeciousness was here recessive to the dicecious 
conditions; (2) that the egg-cells of B. dioica had before fertil- 
ization, ‘‘progame,’’ a fixed sex-tendency, and all of the same 
kind. Were this not the case, not all the offspring could have 
attained the same sex. Had both anlagen, those of the male 
and those of the female sex, been equally active in the eggs and 
had a decision as to the definitive sex depended upon a struggle 
between the anlagen (or upon external influences), the hybrid 
offspring would have been of dissimilar sexes; (3) the egg-cell 
has the tendency to develop into a female plant: ; also the tend- 
ency to give origin to such plants as those from which it arose; 
the physiological sex-determination and the developmental tend- 
ency are both female. 


+ 


No. 504] NOTES AND LITERATURE 819 


The second experiment (B) consisted in fertilizing the egg- 
cells of Bryonia dioica (using flowers from the same plant as 
used in Experiment A) with pollen from the same species. Of 
67 seedlings in the first year 41 came to flower, 21 being male and 
20 female, all pure B. dioica. Combining the results of this 
experiment with those of experiment A it becomes positive that 
the egg-cell possessed a definite sex-tendency, and that the sex 
was not, however, unalterably determined in it; otherwise in 
experiment B all the offspring would have become female as in 
experiment A. The sperm-cells also must have played a role 
in the sex-determination, since until the time of impregnation 
of the eggs by the male gametes the conditions of both experi- 
ments were the same. As far as this experiment discloses, all 
the pollen-grains might have carried the male tendency. After 
union with the egg-cells of female sex-tendency a struggle may 
be conceived to have proceeded, the victory coming now to the 
female tendency, and now to the male, so that the final outcome 
resulted in 50 per cent. individuals with definite male characters 
and 50 per cent individuals with female characters. That this 
was not the case, the third experiment (C) makes clear. 

In experiment C, female flowers of Bryonia alba were polli- 
nated by male flowers of B. dioica. In other words, B. alba fur- 
nished the egg-cells and B. dioica the sperm-cells. The fruit of 
the cross was black, and of 87 seedlings, 76 came to bloom the 
first year, 38 of which were female and 38 male. All the plants 
showed hybrid characters and were completely sterile. The 
decision in regard to the sex of the hybrid must have been 
brought about through the influence of the male gamete (pollen) 
as in experiment B, since B. alba self-pollinated gives rise only 
to monecious plants. There is here a second point in evidence, 
unconnected with the first, against the unalterable ‘**progame’’ 
determination of the egg-cells, and in favor of ascribing definite 
influence to the sperm-cells and to fertilization. The pollen- 
grains of B. dioica can not all have been alike in regard to sex- 
tendency, else the offspring would all have been of the same sex, 
since the egg cells of B. alba were all alike in their tendency to 
give origin to monæcious forms. Again, not all the pollen- 
grains of B. dioica can have had the same sex-tendency, else all 
hybrids, due to the dominance of dicciousness, would have had 
the same sex. Nor can they have been endowed merely with 
the tendency of dicciousness, but without a tendency for a 


820 THE AMERICAN NATURALIST (Vou. XLII 


particular sex. Nor can the sex of the hybrid have been deter- 
mined by the union alone, else in experiment B, where these 
male gametes united with female gametes all with fixed sex- 
tendency (the female tendency as determined in experiment A), 
all offspring would have been alike female plants. Thus there 
remains only this interpretation: That half of the pollen-grains 
of B. dioica were endowed with the male tendency and half with 
the female tendency. Since half of the offspring were male 
and half female, and all of the eggs were of the same sex-tend- 
eney, there can not have occurred a struggle for supremacy be- 
tween the anlagen of the two tendencies (such a condition would 
yield 75 per cent. female plants and 25 per cent. male plants) 
but the male sex-tendency must have dominated completely over 
the female se md Sex-determination si thus ‘‘progame’”’ 
and ‘‘syngame’’alike, but the decision comes ‘‘syngame.’’ 

Experiments were repeated with B. dioica from widely sepa- 
rated regions. Different plants of B. alba were also employed. 
Dr. Correns has had under observation about 1,000 of these 
hybrids. In 27 experiments, using 16 female plants of B. dioica 
from various regions and 4 plants of B. alba, 589 plants were 
raised and all were females. In 17 experiments, using 5 plants 
of B. alba from different regions and 10 plants of B. dioica, 358 
hybrids appeared, 171 pure males and 187 pure females. In 
the body of his paper Correns discusses numerous possible ob- 
jections and criticisms that might be made in respect to his 
experiments and the interpretation he gives to his results. All 
such objections and criticisms are met with very keen and rea- 
sonable explanations. 

Correns made a fourth series of experiments (D) in which 
he used plants from a family of only distant relationship to the 
Cucurbitacee. These were a kind of pink, Melandrium album, 
and a plant from a closely related genus, Silene viscosa. The 
former is a dicecious form and Silene is hermaphrodite. Of the 
seedlings from this cross, using Melandrium as the female parent 
and Silene as the male, 27 plants came to bloom. They were 
all female, though in other respects hybrid in character, and 
sterile. In another experiment (E) Melandrium was fertilized 
with pollen from its own species (as in experiment E) and there 

appeared approximately 50 per cent. male plants and 50 per 
cent. female. The parallel of experiment C with Bryonia was 
also attempted between Melandrium and Silene, using the latter 


No. 504] NOTES AND LITERATURE 821 


as the female parent (the hermaphrodite flowers were castrated) 
and Melandrium as the male parent. All the seed from this 
cross was sterile. 

Numerous experiments with phylogenetic transition forms 
(‘‘polyams’’) between hermaphrodite and monecious flowering 
plants on the one hand and hermaphrodite and dicecious forms 
on the other, i. e., andromonecious, trimonecious and gyno- 
moncecious forms—also with androdiccious, tricecious and gyno- 
dicecious forms—yielded results less definite, it is true, but never- 
theless confirmatory (especially as regards the female tendency 
of the egg-cells of the female plant) of those obtained from 
hybridization experiments between the end forms as in Bryonia 
Melandrium and Silene. 

The main results may be summarized under three heads: (1) 
The germ-cells of female individuals all have the tendency to 
develop into female plants; one half of the germ-cells of the male 
individuals have the tendency to develop into male plants and 
one half into female. (2) The definitive sex-determination 
occurs at fertilization ; the original tendency of the female germ- 
cells can be altered through the sex-tendency of the male germ- 
cells. (3) When at fertilization germ-cells of unlike sex-tend- 
ency unite, the male tendency dominates over the female. 

The experiments seem to indicate that sex is inherited. 
Strictly speaking, however, one can not say that a plant has 
‘<inherited’’ sex, but only that the germ-cells have inherited sex- 
tendencies. Only the anlagen of sex are transmitted from gen- 
eration to generation, not the characters (‘‘Merkmale’’)—the 
cloak that they have woven for themselves (Naegeli). 

Had the hybrids of Bryonia, and those between Melandrium 
album and Silene viscosa not been sterile, they would undoubt- 
edly have split up in such a way that the anlage of diceciousness 
would have been again separated from that of moncciousness 
and of hermaphroditism, respectively, and the second generation 
of these dicecious hybrids would have included pure dicecious, 
hybrid dicecious and pure monecious (or hermaphrodite) indi- 
viduals in the Mendelian proportion of 1:2:1. It remains a 
question whether the dicecious plants would all have had the sex 
of the diccious parent or if both male and female plants would 
have appeared. 

In all cases in which the offspring are divided approximately 
equal in respect to sex, and where the eggs show no external 


822 THE AMERICAN NATURALIST [Vou. XLII 


differentiating characters, as in the great majority of the 
dicecious Metazoa and man, there appears nothing to contravene 
the facts and hypotheses regarding sex-determination as pre- 
sented in the foregoing description of the experiments with cer- 
tain of the higher flowering plants. However, such cases as are 
presented by the aphids and the honey-bee, where all fertilized 
eggs develop into organisms of like sex, are disconcerting from 
the view-point of the above facts. Correns proposes that the 
drone eggs of the honey-bee are incapable of fertilization (de- 
velop parthenogenetically). He inclines also to the idea that 
all the eggs may have the male sex-tendency and that femaleness 
dominates. But since all fertilized eggs develop into females 
this necessitates, on the hypothesis that there are two kinds of 
sperm-cells, the further assumption of selective fertilization. 
The recent discoveries of Meves, Stevens and Morgan, that during 
spermatogenesis -of the honey-bee, certain aphids and phylloxera, 
respectively, one half of the spermatozoa degenerate (and these 
probably are the male-producing kind) now brings these cases 
into very close harmony with Correns’s observations on plants. 
Thus all fertilized eggs must develop into females. The dis- 
turbing question still remains as to just how a parthenogenetic 
female aphid can produce male offspring. 

Again when two kinds of eggs are produced, as by phylloxera, 
daphnids and rotifers, the larger invariably develop (partheno- 
genetically) into females and the smaller into males. Correns 
believes that here a proportion of the eggs may have become 
altered (‘‘umgestimmt’’) in sex-tendency and that their size- 
difference stands in correlation with the difference in size of the 
female and male individuals. In phylloxera this difference, 
however, does not seem significant. Dinophilus apatris seems 
to be a real exception to the hypothesis that sex is determined 
by the spermatozoon. Nevertheless, Correns suggests that a 
portion of the eggs, in consequence of a subsequent alteration or 
originally, may have retained the male sex tendency; or selective 
fertilization may obtain, so that only the larger eggs are fertil- 
ized by female producing spermatozoa and the smaller by male 
producing. However, when caused to develop parthenogenet- 
ically large and small females appear, the difference in size of 
the eggs being related to size differences of the offspring and 
may have arisen through “‘prospective’’ we doers This argues 


No. 504] NOTES AND LITERATURE 823 


for the influence of the spermatozoa in sex-determination and 
for selective fertilization. 

While the facts regarding the honey-bee and Dinophilus offer 
serious obstacles for the general application of Correns’s prin- 
ciples of sex-determination to plants and animals, he finds on the 
contrary much similarity between his results and the cytological 
findings of E. B. Wilson for many of the Hemiptera. Taking 
Protenor and assuming that the spermatozoon with the seven 
chromosomes (including the accessory) carries the recessive 
female tendency, and that the spermatozoon with six chromo- 
somes carries the dominant male tendency, then the correspond- 
ence between the results is complete. The assumptions made 
at first sight seem inconsistent, but they appear more reasonable | 
in the light of Correns’s observations on Satureia hortensis where 
the female tendency—which becomes patent by reason of the 
latency of the anlage of the male tendency (in originally her- 
maphrodite forms) —dominates over the hermaphrodite tendency 
in crosses, when ordinarily the anlagen for hermaphroditism are 
active besides the passive anlagen for the female tendency (in 
gynomeecious forms). 

Correns finds it difficult to believe that the idiochromosomes 
are the material vehicles of the sex-tendency, since the disappear- 
ance of the mate of the accessory chromosome in Protenor seems 
to show directly that it was no sex-determinant. Both germ- 
cells contribute both anlagen; the idiochromosomes can, there- 
fore, simply aid the development of one sex-anlage or hinder the 
other. If we accept the idea that they are also the carriers of 
the sex-anlagen then the spermatozoon of Protenor with six 
chromosomes would have no sex-anlage ; and ephebogenetically de- 
veloped it would give rise to an organism without sex. If the 
anlagen are present outside of the idiochromosomes then the 
spermatozoon thus developed would give origin to a hermaph- 
rodite form. There probably are not two kinds of eggs e 
contrary assumption rests upon another; i. e., selective fertiliza- 
tion. There is no experimental oide of selective fertiliza- 
tion in the case of Hemiptera. If one accepts Wilson’s sug- 
gestion that in cases like Nezara (where the idiochromosomes are 
alike) half of the spermatozoa have an active idiochromosome 
(aiding the development of the female sex) and half a passive 
one (permitting the male sex to develop), and that the latter 
may, in consequence of its passivity become reduced (as in 


824 THE AMERICAN NATURALIST [Vou. XLII 


Lygaeus), or have entirely disappeared (as in Protenor), all the 
eggs may then carry idiochromosomes of like activity and there 
is no need for selective fertilization. These cases accordingly 
seem to lend themselves for interpretation very well to the prin- 
ciples above stated for sex-determination in Bryonia. In Men- 
delian terminology, females are pure zygotes, i. e., homozygotes ; 
males are hybrids, i. e., heterozygotes. Segregation takes place 
at maturation and produces by the homozygote organism one 
kinds of germ cells and by the heterozygote two kinds, 7. e., male 
and female in sex-tendency. 

The physiological male or female property of the germ-cells 
which provides for their union and what relates thereto, must 
not be confounded with the male and female tendency of the 
germ-cells, or the disposition to give rise to descendants whose 
germ-cells are again male or female. Though these principles 
of sex-determination and inheritance discovered for higher 
plants may not be capable of universal application, there are 
several points in which the different methods may agree: (1) 
That each germ-cell has originally a fixed sex-tendency ; (2) that 
the germ-cells of one sex (either the male or the female) have 
only one and the same sex-tendency, and those of the other partly 
the one, and partly the other; and (3) that a primarily fixed 
differentiation in the developmental vigor of the germ cells with 
different sex-tendencies that unite at fertilization, brings about 
a decision favorable to one or the other sex. 


(No. 503 was issued on November 20, 1908.) 


INDEX 


NAMES OF CONTRIBUTORS ARE PRINTED*IN SMALL CAPITALS 


ae (hg Xerophytic, J. F. Mo- 
CLENDON, 308 


a Wi . and A. H. WRIGHT, 
The ‘Swamp Cricket Frog, 39 
ALLEN, J. A., Fault Bars in Feath- 
ers, Osear Riddle, 550; The Garter- 
Snakes, A. G. Ru thven, 552; Spe- 
cies, 592; ‘Down’? in Pluma age, 
693 


Ameba Studies, G. N. C., 
Amphibia, Caudate, reson Roy 


a IE, 

Ander J. F., and J. Rosenau, 
Enberitense through Placental Cir- 
culation, F. T. L., 134 

Araneads, Activities of, THos. M. 
ONTGOMERY, 

ARTHUR, J. C., The Species Question, 
243 


B. R., Centers of A 615 
n morph- 


EEBE, WILLIAM, iige of 
Color in ' Birds, 34 
havior, Animal, H. 8. JENNINGS, 
207, 355. 

Behr, "Kamil gr Human Heredity, 
F. A. Woops, 685 


Bell, E. T., TE binanin =i a 
Emb ry 0s, CO. R. STOCKARD, 

Bermuda Decapod Fauna, PE E. 
VERRILL 

Berry, ©. S., par Behavior, H. 8. 
gin Akala 
so “Chianti E., The Species 
Quest 


Biological Laboratory of the Bureau 
of Fis t Woods Hole, F. B. 


UM 

Biometrics, 418 

Biometry and Googe =e CHARLES 
LINCOLN EDWARDS, 

Bird Life of Illinois, S. L FORBES, 


Birds, Color in, WILLIAM C. BEEBE, 


BLACKMAN, F. F., Chemical Mechan- 
ies and the Living Piant, 633 
LLEY, Henry W., The Constancy 
of Mutants, 171 
Bower, F. O., Origin of a Land 
Flora, DovcLas ouros CAMP- 
BELL, 732 


Braus, Dr., Transplanting Limbs and 
on aT of Nerves, A. J. G. 
143 


a td of Swamp Cricket Frog, 
. WRIGHT and A. A. ALLEN, 


Breinl, A., and J. E. S. B Wane 
Trypan moses HENRY B. WARD 
630 

BRISTOL, C. L., Otter Sheep, 282 

BRITTON, NATHANIEL LorD, The Spe- 


Brown, B., Conrad Fissure, 629; 
Anklysauri uride, 629 

BRUES Tsee THOMAS, Tropisms 
of Insects, 297 

Budgett, J hits Samuel, DAVID STARR 

AN, 

URRILL, T. J., The Species Ques- 
tion, 27 2 


C., G. N., Protozoa, 62; Amoeba 
‘Studies, 422 
.. H. L., Crinoids, AUSTIN HOBART 


LARK, 

Cambarus Bartonius Bartoni, FLOYD 
E. CHIDESTER, 710 

Camel ies me Miocene, HAROLD 

K, 79 

AMPBELL, DOUGLAS HOUGHTON, 
Symbiosis i in Fern Prothallia, 154; 
Ori of a Land Flora, F. O. 
Bower, 732 

Cannon, W. A., Origin of Structures 
in Plants ee as 9 

C., Pelycosauria, S. W. 

WILLISTON, 628 

Carr, Harvey and Watson, Animal 
Behavior, H 


C S 
Crinoids, Max Weber, 203; The 
Genus Ptilocrinus, 541; Ecology 
of Crinoids, 717 
Clark, Austin Hobart, Recent Crin- 
oids, a Sa C., 3 
, Cyto ological Studies on 
sae A A and Vaucheria, BRAD- 
LEY M. Davıs, 616 


Cine and ona Parasitism, 
HENRY B. Warp, 630 


825 


NTS, FREDERIC E., The Species 


, The Florissant 


Color, in Birds, WILLIAM C. BEEB 
34; ag ome for I Naturalists’ 


ACOB REIGHARD, 

Coloration of Plethodon Cinereus, 
HueuH DANIEL REED, 460 

Cook, Harotp JAMES, Rhinoceros 
from the Lower Miocene of Ne- 
iy 543 

Cook, O. F., Evolution without Iso- 
SnAg 727 

Correns, C., AAT aia of Sex, 
H. E. Jorp , 811 

COULTER, M) The Species Ques- 
tion, 272 

T H. C., The Species Ques- 


, 265- 
Crinoids, Ecology of, Austin Ho- 
T CLARK, 717 


DALL, WM HL, Hamburg Magellan 
Expedition, 562 
‘DAVENPORT, GERTR 


TRUDE ee 
ee tis Heredity of Hair 


Form 
Davenport, to. B., Spurious Allelo- 
morphism, W. Zz SPILLMAN, 610 
DO M Enteropneusta, W. E 
RITTER, 622 
VIS, BRADLEY M., Polar Organiza- 
tion of Plant Cells, 501; The Cilia- 
ytological 
Vau- 


Davi 


marck ’ Manu- 
HARLES, Fap Evolution 
Mammals and the 
portance of their prnaione thay 109, 
Desieation of Rotifers, D. D. WHIT- 


Digby” L., and J. B. Farmer, Apo- 
in Ferns, BRADLEY M. 


Resistance in Plants, HENRY 
: W. BOLLEY, 

Dobel, c. Clifford, Protozoa, G. N. 
a Dofiein F., Ameba Studies, G. N. 


INDEX 


Echinodermata, 203, 350 

EDWARDS ARLES LINCOLN, Biom- 
etry and Taxonomy, 537; Holo- 
thuriodea, Hjalmar Ostergren, 620 

Elderton, Ethel M., and Arthur 

Se huster, Heredity, F. A. Woops, 

685 


Elpetiewsky, W., Protozoa, G. N. C., 


ar pra of Myosurus Minimus, 
. SWINGLE, 582 

Mirel e 622 

Evolution, of Species, JoHn T. 
GULICK, 48; and Heredity, 58; 
of the Tertiary Mael, CHARLE ES 
DEPÉRET, 109, , 303; without 
Isolation, O. F. Cook, 727 


Fantham, H. B., Protozoa, G. N. C., 


62 
Farmer, A B., and L. Digby, Apo- 
y Fern rns, BRADLEY M. 
Davis, 743 
Fasciations of Known Causation, 
N 


LEXAN 
Faunas, Dwarf, HERVEY W. SHIMER, 
2 


Fischer, E., Effect of Environment, 
N Lutz, 60 
Florissant Expedition, 
COCKERELL 
FORBES, mS. A A. Bird Life of Illinois, 


E D A 


Fossil, Skeletons, ADAM HERMANN, 
43; Mammals from Egypt, T. D. 
A. C., 

Frog, Swamp Cricket, A. H. WRIGHT 

and A. 


Dici Determination of Sex in, M., 
Froth in Spittle Insects, BRAXTON 
H. GUILBEAU, 783 


G., A. J., Transplanting Limbs and 
Development of Nerves, 143 
GAGER, C. Sruart, Radium Rays, 


Galippe, V., Human Heredity, F. A. 


, 
Galton, F., Biometrics, RAYMOND 
Gay, F. P. and E. E. Southard, In- 
heritance through mae Cir- 
culation, F. T. L. 
Geminate Species, ae STARR JOR- 
AN, 73 


INDEX 


Geographical ee A. E. 
V: 

oae T. H. MORGAN, 

GUILB BRAXTON H., * Froth in 
Spittle "Insects, 783 
ULICK, JOHN T., 
Selection, 48 


Isolation and 


Hair Form, Heredity of, GERTRUDE 
ENPORT and CHARLES B. 
sae n G. van T., Animal Be- 
hav . S. JENNINGS, 207 
Hands, € ‘aaspng the, Inheritance of 
nner of, FRANK E. Lutz 


Ha arper, R. A., Polar ae vin, 
E Plant Cells, BRADLEY M. Davi 


Hanus, J. A., The Species Question, 


Harrison, E G pidge perae. 
Limbs and Development of Nerves 


A. J. 

Hartman “and Prowazek, Protozoa, 
G. N. C., 62 

Harvey, Carr and Wa tson, Animal 


Behavior, H. 8. JENNINGS, 355 
a “ea eg , Sauropodus Dino- 


Heidinger, W., Cytological Studies 
Sapro. rolegnia ‘cn Vaucheria, 
Relating M. Davis, 616 
HEMIN oe ERNEST E., Placobdella 
Pediculata, 527 
Bertin, 610; of Hair Form, GER- 
E C. DAVENPORT and CHARLES 
B. "DAVENPORT, 341; Human, F. A. 
‘oops, 
HERMANN, ApaM, Fossil Skeletons, 
43 


Heron, David, Heredity. 
Woo 


Hertwig, R , Sex in Frogs, M., 67 

HILL 6, The Species Question, 
272 

HITCHCOCK, The Species 


À E., 
2 


uestion, 
Holothurians, 620 
MARIAN E., Somites in the 


k, 466 
s, HENRI, Fasciations of Known 
Onasa 81 


rede pee pta Davip STARR 
JORD 197, 8 

iea ‘of ana monax L., 
À. 


HARLES SHULL, 

Inheritance of the Manner of Clasp- 

ing the Hands, FRANK E, Luz, 
195 


827 


JENNINGS, H. S., Behavior of the 
Higher Animals, 207, 355; Mind 
in Animals, 7 

JOHNSON, D. S., The Species Ques- 
tio 17 


“ Down ”’ in Plum- 
(aes; A mae 


AN, STARR, Geminate 
ieee, 73; ; Ichthyologieal, Notes, 
197, Valve in the Heart of 


ne es, D. apo 496 ; Tohn 
muel Budgett, 7 

J ord David Siar, “Fishes, FRED- 
c T. Lewis, 286 


d Seri H. E., © Correns’s Memoir 
on the Determination of Sex, 811 


gig sata Paul, The Effect of En- 
ment, FRANK E. Lutz 
oY. L., Darwinism To- -day, 


Re ite 58 

Kleinsieck, Paul, and Th. Valette, 
Code of Co lors for Naturalists, 
JACOB REIGHARD, 566 

Koroip, ee $. The Eel, Johs. 
Schmi dt, 

Korschelt, B "tia, M., 428 


Lamarck Manuscript, BasHrorp 
EAN, 145 
Lee, ,A., Biometrics, RAYMOND 
PEARL, 418 
LEE, ERIC E 394 
Leg Tendons of Insects, C. W. 
WORTH, 452 


Lepidoptera, 559 

LEWIS, FREDERIC T., Darwinism To- 
day, KELLOGG, 58; Inherit- 

ance through the Placental Cir- 
culation, 134; Fishes, David Starr 
Jordan, 286 

Loos, A Chinese Parasite, Henry B. 
WARD, 432 


LUTZ, FRANK E., The Effect of En- 
vironment, 60; Inheritance of the 
Manner of Clasping the Hands, 
195 


M., Sex Determination, "i cms a 
mental Zoo oology, Hans Przibram, 
283 


McCLeNDo. J. F., Xerophytic 
Adaptations, 308 
Doue D. T., The Species 
Question, 249 
Marine Laboratories, ALFRED G. 
YER, 


QUETTE, W., Polar Sg Paea 
of Pinet Cells, Brapiey M. Davis 


828 


MAYER, ALFRED G., Marine Labora- 
tories, 533 

oe Ratio and Types of La- 

ney, G. H. SHULL, 43 

Meosead MERY, Tuos. M., Activities 

of Araneads, 69 

Moopiz, Roy L., nag of Cau- 
date Amphibia, 361 

J. E. S., and A. Breinl, Pro- 

., 62; Trypanosomes, 


ie 
S 
= — 
> pn 
= 
= 
D 


Müller, Conrad, Regeneration, SER- 
GIUS MORGULIS, 749 
Musgrave and Clegg, a reg of 
Parasitism, HENRY B. Warp, 630 
Mutants, the Guus of, Paci 
; BOLLEY, 171 
NICHOLS, JOHN TREADWELL, The 
Silverside, 731 
Noorduijn, G i. W., Spurious Al- 
lelomorphism, W. S SPILLMAN, 


Notes and Literature, 58, 134, 197, 
- 283, 350, 418, 491, 546, 610, 685, 
732, 800 


O. L., Form Variation in Am- 
bisstoma ge Ms , J. H. Powers, 

Origin of pce har in Plants, W. 
A. CANNO 

go ie ‘Hjalmar, sig igi sae 
CH s L. Epwarps, 620 


Otter | zn Cc. L. oma ly 282 


Paramecium, LORANDE Loss Woop- 
RUFF, 520 
Parasites, Phenogamous, CHARLES A. 


Parasitic Plants, CHARLES A. WHITE, 
98 


Parker, G. H., Zoological Progress, 
115; Vertebrate Eyes, 601 

Parker, W. N., Wiedersheim’s Com- 
parative Anatomy of Vertebrates, 
L. W. W 


PEARL, RAYMOND, “Biometric, 418 

Pearson, K., Bio ies, YMOND 
PEARL, 418; sr Heredity, A. 
P. Woops, 685 

Phenogamous Piai, CHARLES A. 
WHITE, 1 

Physiology, FREDERIC S. LEE, 394 

Placobdella Pediculata, ERNEST E. 

EMINWAY, 527 

Plate, C., Effect of Environment, 

FRANK E. . Lurz, 60 


| 
| 


INDEX 


Eao J. B., The Species Ques- 
tion, 272 


Seas J Form Variation in 
Amblystoma tigrinum, H. L. O., 


136 
Prandtl, H., Ameba Studies, G. N. 


bf 
Prothallia, Fern, Symbiosis in, 
Dovetas HOUGHTON CAMPBELL, 


154 
Reins. S., Protozoa, G. N. C., 62 
eed. W., ' Centers of Ossification, 


Przibram, ‘Hans, Experimental Zool- 
83 


Ptilocrinus, Ta Genus, AUSTIN Ho- 
BAR : ae 541 

Punnett, R. C., Enteropneusta, W. 
E. hi 622 


Radium oa C. STUART GAGER, 697 
EED, HucH DANIEL, Coloration of 
Plethodon pmo 460 

REIGHARD, B, Code of Colors for 
Noeiivaliots, $ P. ’ Kleinsieck and Th. 
Valette, 566 
hin 


Rhinoceros from Lower Miocene of 
` Nebraska, HAROLD 


AMES COOK, 


543 
Riddle, Oscar, Genesis of Fault aita 
J. , 550; pg own’? in Plum 
e, 3. A. A., 


ag 
os W. E. Seed E 622 
Rose Anderson, 
Takeritan through Placental Cir- 
culation, F. 


Rotifers, Desiccation of, DD. 
WHITNEY, 665 
RUTHVEN, ALEXANDER G., Faunal 


Affinities of the Prairie Region of 
Central North America, 388 
Ruthven, A. G., The Gartersnakes, 
J. A. A., 552 
Shaudinn, F., Amæba Studies, G. N. 
Schmidt, Jaa, The Eel, CHARLES 
. Koror, 491 
Schubotz, H., Ameba Studies, G. N. 


C., 4 

Schuster Arthur, and Ethel M. 
Elderton, Heredity, F. A. Woops, 
685 


ses tam Jonge, <= of Color in Birds, 
m C. BEEBE, 34 
Sia H. T Valve in the Heart of 


L, A., J 
tutes for Smoking Tobaceo, 682 
HER Dwarf Fauna 


. unas, 
472 


INDEX 


Silverside, JOHN TREADWELL NICH- 
Skeletons, Fossil, ADAM HERMANN, 


Sheppard, W. Po Biometrics, RAY- 

MOND 418 

Shorter Articles and Correspondence, 
195, 282, ory 682, 799 

SHULL CHAR s A. Abnormal In- 
cisors of TERAN Monax L., 457 

SHULL, G. H., The Species Question, 


272 3 
Slonaker, J. R., Animal Behavior, 
= S. 5 


To Inheritance through Pla- 
eat Cireulation, ERL 
cay sie Pron the Chick, Marian E. 


Southard 1 E. E., and F. P. Gay, In- 
heritance through Placental ’ Cir- 
culation, F. T. L. 

Species, Evolution ti JOHN T. 
GULICK, 48; Gem inate, ise 

TARR JORDAN, 73; What is a 
Species? S. W. WILLISTON, 184; 
The Species Question, D. S. ‘Jou HN- 

LES E. BESSEY, 


yi 
A. E. Hrroncock, 272; 3. 


ALLEN, 592 

Spengel, J. W., Enteropneusta, W. 
E. RITTER, 622 

SPILLMAN, W. J., Spurious Allelo- 
morphism, 610 

Spirochætes, HENRY B. WARD, 374 

Spittle Insects, Braxton H. GuUIL- 
BEAU, 783 


STOCKARD, . T., Regeneration, in 
Frog Embryos, 138; in Moulting 
in Crustacea, 140 


Strasburger, 1 E, erar in Ferns, 
BRAD , 14 


‘Student, oe P onler Vi RAYMOND 
PEARL, "41 

SUMNER, F. B., Biological Labora- 
tory of the Bureau of tisheries at 
Woods Hole, 317 

SWINGLE, Leroy D., Embryology of 
Myosurus Minimus, 58 

Symbiosis in Fern Pro thallia, Doug- 

OUGHTON CAMPBELL, 154 


Taxonomy and sana td CHARLES 
LINCOLN EDWARDS, 


829 

Tobacco, Juvenile Substitutes for 
Smoking, W. A. Setc 

Tropisms of Insects, CHARLES 
HOMAS BRUES, 297 


Tutt, J. W., Hybrid Lepidoptera, 
T. D. A. CoCKERELL, 559 


Vermin, A Society for the Study of, 
HENRY B. 

VERRILL, A. E., Geographical Dis- 
tribution, 289 

Vertebrate Eyes, G. H. PARKER, 601 


Walker, E. L., Amæba Studies, G. 
22 


B., Trypanosome Dis- 
06; The Spirochætes and 
their "Relationship id pesg ta 


eases in the Philippines, 561; Evo- 
lution of Parasitism, 030 

Washburn, Margaret F., Min 
Animals, H. B. JENNINGS, 207, 
7 


54 

Watson, J. B., Behavior, 
H. S. JENNINGS, 355 

Weber , Crinoids, Stalked, 


hubby C. M., Ameba Studies, G. 
., 422 


Warr ITE, ’ On ARLES A., Phenogamous 
Parasites, 12; Parasitic Plants, 98 

WHITNEY, Dp Desiccation of 
Rotifers, 665 

Wiedersheim, R., 


Comparative An- 
atomy of Ve ertebrates, L W. 
W 


WILLIAMS, i , Comparative An- 
atomy of Vertebrates, 72 


WILLISTON, , What is a Spe- 
cies? 184; ` Pelycosauria, R G 
i 628; Conrad Fissure, B. 
Brown, 629; Ankylosauridæ, B. 
Brown, 
WOODRUFF, LORANDE Loss, Para- 
age 52 


F. A., Human Heredity, 685 
Woonwoxms, ©. W., Leg Tendons of 
Inset 
WRIGH rs nE and A. A. ALLEN, 
Breeding Habits of the Swamp 
Cricket Frog, 39 


Xerophytie Adaptations, J. F. Mc- 
CLENDON, 30 


830 


Yamanouchi, Sh., The Cilia-forming 
Or y EY 


: amy in Ferns, 
BRADLEY M. Davis, 743 

Behavior of the 
Higher Animals, H. S. JENNINGS, 
207 


INDEX 


Zoological Progress, G. H. PARKER, 
Zuelzer, Dame deg et, The Influence of 
bee „~ ration on Moulting in Crus- 
EG R. STOCKARD, 140 
Zur Bera, Otto, Mind i in Animals, 
H. S. JENNINGS, 754 


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The American Naturalist 


in 1867, Devoted to the Advancement of the oe Sciences 


Monthly Journal, establish 
with Special ates: to the Factors of 


Organic Evolution nih 


CONTENTS OF THE MAY NUMBER 


phical Distribution; Origin the Bermuda 
On the Inte: orn Pe Ce AMi omger 
; rp ono 
CHARLES THOM 
~~ eae of Te the Im 
cane Serer Professor Cu HARLES proeime 
On Xerophytic Ada ons of Leaf Structure in Yuceas, 
Profi r J. F. MCCLENDON, 
B of the Bureau of Fisheries at 


The “rage, A 
Wood's Hole, Mass.: Report of Work for the Season 
of 1907. Ld Francis B, SUMNER, 

Form in Man, GEnTKeDe C. DAVEN= 


RT, 
Notes and Liierature: Serna ipep gare In- 


terest in Recent Crinoids, H, L. C. Animal Bee 
rarna ren Work on the Behavior of — Higher 
Animals, Professor HERBERT 8, JEN 


CONTENTS OF THE JUNE NUMBER 
The Ancestry of the Caudate Amphibia, Dr, Ror L 
Moopre, 
The Spirochetes and their oe to other Organe 


pa 


CONTENTS OF THE JULY NUMBER 

A New Mendelian Ratio and Several of Latency. 

Dr. GEORGE HARRISON SHULL. Type 

Leg Tendons of Insects. Professor C, W, WOOD» 
WORTH. 

Abnormal Incisors of Marmota Monax L. CHARLES 
A, SHULL. 

A oe on n ———— of Plethodon Cinereus, HUGH 

cae e oe a on the Order of Succession of the 


Somites in the Chick. Professor MARIAN E. HUB- 
BARD. 


CONTENTS OF THE_AUGUST NUMB 
e Mid-summer Bird Life of Illinois: A esac 
Study. Professor 8. A. FORBES. 

The Life moa of Paramecium when subjected to s 
Varied vironment, Dr. LORANDE Woon- 
RUFF. 

Placobdella Pediculata n ERNEST E., HEMINWAY. 

—_— marc pase aon: “ane Atlantic Coast, DE. AL- 


Shomatry eng a emma Son raged Professor 
CHARLES LINCOLN 

recnpoeuaniters Ta Genus Ptilo- 

e Lower Miocene rales HAROLD 


Notes cond Literature: Plant Cytology—Some Recent Re- 
search on the ——_ Organ of = Aa p 
BraDLEY M. Davis. Ornithology—Rid 
Genesis of Fault-bare and the Cones of alton 
nat icine Dark Bars in Feathers, J. A. A. ‘Her- 
see: 9 a od a a ag por ome 

= ps of the Garter-snakes, Lepidoptera 
ybrid Lepidoptera, Professor T.D, A, CocCKERELL. 


Dr, Leroy D. 

Another Aspect of the Species Question. Dr. J. A. 

The- y oaen of the Lateral Eyes of Vertebrates 
essor G. H. PARKER. 


W: J. SPILLMAN. Human Anatom: 


ons, 
Pryor on Sexual and Family ‘dense tamer in Centers - 


of Ossification, C. R. B. Pian 

logical Studies on Saprole ni cua v Vaucheria, 

DR. BRADLEY M. erat rn = peaa 

ea, Professor CH EDWARDS. En- 

Recent tates on che retool 

neusta, Professor W. E. RITTER. Vertebrate 

on Paiscomuni of North 

America; Barnum Brown on the Conrad fof ag 

= on the ee wW- 

ILLISTON; Parasitology— „Evolution of 
Parasitism; Trypanosomes, H. B. W. 


CONTENTS OF THE OCTOBER NUMBER 
estations of the Principles of Chemical 
Mechanics in the Living Plant, Dr, F, F, BLACK» 
MAN. 
The Desiccation of Rotifers. D. D. WHITNEY, 
On the Habits and the Pose of the Sauropodous Dina- 
saurs, especially of Diplodocus. De. OLIVER P. 


Har. 
Shorter Articles and Correspondence: Juvenile Bub- 
stitutes for Smoking Tobacco, Professor WILLIAM 


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