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DRPHOLOGY ANE BIOLoGy SOME TUBELLARIA FROM me tHE MISSISSIP?| RIVER
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MORPHOLOGY AND BIOLOGY OF SOME TUBELLARIA } FROM THE MISSISSIPPI RIVER BASIN
RUTH HIGLEY A. B. Grinnell College, 1909.
THESIS Submitted in Partial Fulfillment of the Requirements for the Degree of
DOCTOR OF PHILOSOPHY
IN ZOOLOGY
THE GRADUATE SCHOOL OF THE UNIVERSITY OF ILLINOIS
1917
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I HEREBY RECOMMEND THAT THE THESIS PREPARED UNDER MY SUPER-
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ENTITLED MORPHOLOGY AND BIOLOGY OF SOMF TURBELLARIA FROM
BE ACCEPTED AS FULFILLING THIS PART OF THE REQUIREMENTS FOR THE
DEGREE OF.............DOCTOR OF PHILOSOPHY
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TABLE OF CONTENTS
INTRODUCTION History Before 1900 Since 1900 Mississippi Valley forms Scopé of present paper Economic importance Acknowledgement Technique Methods of collection Methods of culture Methods of histological preparation Methods of study Living material Permanent mounts Difficulties
Part I. BIOLOGY Field notes 13 Springs (General conclusions from a study of
eleven springs) Teraporary puddles (Typical conditions in nine- teen collections) Streams (Detailed study of five rivers) Ponds (Study of five ponds, summary of forty others)
Biology Reaction to oxygen and carbon dioxide Reaction to light Reaction to temperature Reaction to other forms Food Enemies and protection
Part II. MORPHOLOGY Detailed study of Strongylostoma rosaceun Morphology of body systems Development Life Habits General study and notes on twenty species Family Plansriddae Planaria maculata minor nov. var. Planaria velata Stringer 1909 Wamily Catenulidae
Stenostomum leucops 0. Schmidt 1848 Stenostomum tenuicauda vonGraff 1911 Stenostomum giganteum nov. spec. Stenostomum glandifera nov. spec.
Family Microstomidae Microstomum caudatum Leidy 1851 Macrostomum sensitivum Silliman 1885 Macrostomum album nov. spec.
Family Prorhynchidae 121 Prorhynchus stagnalis M. Schultze 1851 Prorhynchus applanatus Kennel 1888
Family Typhloplanidae 126 Rhynchomesostoma rostratum Muller 1773 Typhloplana viridatum Abilgaard 1790 Mesostoma ehrehbergiiFocke 1836 Mesostoma simplex nov. spec.
Family Dalyellidae Dalyellia dodgei vonGraff 19b1 Dalyellia fusiforma nov.’ spec. Dalyellia alba nov. spec.
Dalyellia megacephala nov. spec.
Part III. CONCLUSION AND SUMMARY General discussion Sunmary
BIBLIOGRAPHY
INTRODUCTION
Altho of seeming insignificance, the Turbellaria as
a class present certain characters of morphology and life-history
which make them of especial interest. Furthermore, their biologic
processes and life habits in relation to other forms, shed some
light upon general problems of common existence. A knowledge of
any group of animals is of value from a phylogenetic standpoint as
well as in the explanation of the interdependence among various
types, So this group, standing, as it were, at a point of connect~
ion between the very Lowest phyla, the aberrent parasitic worms,
and the more specialized higher types, makes possible an under-
standing of one of the important steps in the evolution of the
animal kingdom. The simplicity of anatomical. structure and Lack of
conspicuous detail altho thys especially important in a comparative
way, also enables these forms to carry on an existence almost un-
suspected and generally entirely overlooked. The fact of the wide-
Spread distribution in both salt and fresh water passes, for the
most part, unnoticed.
While the fresh water Turbellaria of Europe have been
recognized and carefully studied for nearly one hundred and fifty
years, the American species have received little attention. The
earliest records for this country are those of Leidy. In 1848,
he gave the first brief description of the now well-known and very
+ common Planaria maculata. He also studied rather completely Phago-
cata gracilis, distinguishing the fundamental points in which it
differed from the Planaria. Later (1852) he added several other
species to the list. No other studies were reported until a paper
by Silliman appeared in 1885. This was also descriptive and syste-
matic in character. The first morphological work was that by Ott
(1892) who made the common Stenostoma leucops 0. Sch. the basis of
a detailea histological study. Woodworth (1896) ana (1897) next
published results of collections made from rather widely separated
localities. He named four new species and added full descriptions
of twelve others.
| Since 1900, there have been a number of papers, a few
descriptive, but by far the most the results of experimental work.
Of the first type, the paper by vonGraff (1911) is noteworthy. In
this, he gives descriptions and notes of some seventy-five species.
Several other weiters have from time to time added a few forms, but
this is all. On the other hand, in a vast amount of experimental
work the more common species have been used. Child's work with
the common flatworm has explained a large number of facts of far~
reaching general biologic Significance. Other investigations, some
of them exhaustive, have dealt with the more primitive rhabdocoels
as well as with planaria. Among the many writers along this line
are Kepner (sq) and (1915), Curtis (1905), Pearl (1903), and Kei-
ler (1910) .
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Altho they are free-living forms, a few cases have been reported in which they are parasitic on molluscs and it is in these species that a beginning has been made in the study of the embryology and life-history. Two writers, Linton (1910) and Stan- living on Modiolus.
eer “The Turbellaria of the central and western states are almost unknown, Woodworth (1897) and Stringer (1909 - 1913) have
published descriptions of five new species from Illinois and Nebra-
ska. Eleven other f orms, found also in the eastern states, have been reported from a few localities in Illinois, Nebraska, Michi- gan, and Wisconsin, but these are all. That some species, at least, are present in great numbers is evident from the various collecte ions for experimental Studies. The whole Mississippi valley region with its lakes a8 almost numberless ponds furnishes conditions
in many respects ideal for such types, and their existence will sooner or later be demonstrated.
In fact, both Planaria and rhabdocoelida are of much more common occurrence than is generally supposed and for several reasons are especially valuable for Study. First, they are available as living reproducing animals thruout the year. Then, they are good for experimental work since they illustrate a somewhat primitive phylum, one in which the body structure is very different from that commonly encountered, Well adaptéd to such studies, by their sim-
plicity and great vitality, they have come to be the classic speci-
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mens employed both for elementary experiment and for complicated
investigation. The free-living method of life, together with the
Simple fundamental anatomy, when compared with the specialized anda
much changed condition of the nearly related parasitic worms shows
Clearly the variations possible and actually brought about by a
different mode of life. As a whole, the group is of more than
ordinary interest.
Always considered of no importance economically, their possible relation to other forms has been overlooked, so that onl: by chance have their habits of parasitism and voracious feeding been discovered, and there is need of further investigation along this line.
In the present paper, a brief study is made of a few forms found in small lakes and ponds in Illinois and Iowa. This covers three phases: First, a summary and comparison of the types of habitat which deals with such environmental factors as flora, whether algae or higher water plants, animal comaunities, whether few or many, bottom, whether sandy or muddy, and also the general water conditions, second, a few of the biological aspects, this Outline comprising a study of the reactions to the various stimuli; third, a morphological description of nine new species and addition- al data concerning twelve others. These descriptions embrace to Some extent histological structure as well as §ross anatomy, and a@ number of points regarding the distribution and characteristic
variations of well-known species. In the case of one form, a
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resume of the embryological stages is also given. Six plates which contain toto drawings of all the species are included, besides separate sketches of isolated parts.
The work was done mainly at the University of Illinois at the suggestion of Dr. H. B. Ward, and to him I wish to express my gratitude for help and inspiration. I also had the opportunity to make collections and to study at the United States Biological Station at Fairport, Iowa, and my thanks are due to the director, Me. A. F. Shira, and to Mr. H. L. Canfield, who aided me in every way possible. I am also indebted to Mr. R. L. Barney, of the United States Biological Station at Homer, Minnesota, for material sent me, and to Miss Elizabeth Bodfish, of the University of
Illinois, for many specimens from this locality.
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TECHNIQUE Collections were made in three ways. Surface or open water was dipped with a pail or jar, and as large amounts as pose
sible carried back to the laboratory, partly for the purpose of
ascertaining whether or not specimens were present, and partly for — use in aquaria. Then with a long-handled dip net, masses of algae and water-weed were taken either from shallow places along the shore line, or from the sur face out in deeper water where they floate in great tangles, or from the bottom. In some cases, a good deal ef water was drained off and the mass of damp weed carried
in, to be later plunged in pond or tap water. As a third method,
the alga was taken with a minimum of disturbance, and kept as nearly as possible in its relative shape and condition. In small ponds where the water was not over three feet in depth, collections were made out in the middle and often the leaves and stems of water lilies and other large plants were gathered. These were kept by themselves in clear water. The stems and undersides of the lily pads were generally covered with very fine algae or a growth of diatoms, which made a good shelter and feeding ground for many small forms. The bottom mud with its loose covering of organic debris was generally dipped up separately, with a small amount of water, Samples were taken both near shore and out in the deeper
portions. Many collections were kept alive in the Laboratory for
lengths of time varying from a few days to six months. The algae
and other debris were floated out in either tap water, rain water,
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9 or pond water. Glass jars were used for this purpose, some very
shallow and some eighteen inches deep. In cases where a few indi- viduals or a special bit of water weed was to be isolated, shallow glass stenders could be employed. About half the aquaria were kept covered to prevent evaporation and the others left open, water being added at intervals. The amounts of suhlight varied. A few jars have been so placed as to have sun all day but most have had it for only a few hours at a time and a good many not at ell. Generally the temperature of the aquaria was that of the room. <A few however have been held at much higher and a few at a much lower point. Balanced and favorable conditions are always easy to obtain, and in & number of cases there was a good deal of asexual reproduction by budding, as a result of fairly perfect vegetative processes. Occasio ally when a number of surrounding details were precisely favorable, even the sexual Pevroauetion could be studied and the life habits made out with some degree of completeness.
The aquaria have never been artificially aerated, but an attempt has always been made to furnish oxygen by means of plant life. In the case of planaria, food has peen provided in the shape of small bits of meat, while in the jars where rhabdocoels were liy- ing there has always peen an abundance of other animal forms to Supply all possible need.
A. In preparation for histological study, the specimens have been killed and fixed with some measure of success. The indi-
viduals in some cases were anaesthetized with a solution of cocaine
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hydrochlorate followed by chloretone of varying strengths until they were quiet and expanded. The fixation was done with corrosive acetic solution. Material was generally stained in toto With Ehr= lich’s hematoxylin, embedded in paraffin, and sectioned 4 to 8K
in thickness. A counterstain of eosin or erythrosin was sometimes used. With planaria, a solution of one part nitric to three of water gave good results as a killing fluid. Cold corrosive subli- mate was found useful in many instances, and under special condi-
tions a warm solution was valuable.
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11 METHODS OF STUDY
Specimens were studied either alive or in permanent mounts. When living, they were controlled by means of a pipette and were isolated either in concave watch glasses or on a slide, The movements could be checked by burying in a drop of quince-sced jelly or by adding small amounts of cocaine or chloretone to the water. The jelly is of value in studying the cilia or the muscular system, for it increases the violence of action while retarding the speed. It also shows more clearly the relative position of various organs, for the animal will turn over again and eens thus afford- ing good lateral and ventral views. The objection to its use lies in the fact that Baie very thick, opaque solution will be dense enough to reduce appreciably the movement. The chloretone has the advantage of quieting thoroughly, but it also causes the specimen to become so limp as to be easily injured, and to begin to disinte- grate very soon. Another way is to confine the animal by the weight of the cover glass or by a minimum amount of water on the slide. This method flattens the body so as to make it more transparent. The several organs will be pushed entirely out of their natural posi- tion but can be studied separately better than under any other con- ditions, since they can be partially isolated and their interrels= tionships made out. Because of the transparency and lack of rigid-
ity, many details are clearer in the live tissue than in permanently
mounted material, where a large amount of cellular contraction is
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12 unavoidable. Many details of structure, especially those of the
nervous system, are clear only from a study of prepared material, Serial sections in the several planes have been used to verify and correlate findings in the various body systems.
Some little difficulty is experienced in an attempt at a detailed study ofthe tissues. The extreme contractility and sensitiveness make it almost impossible to kill and fix material ina condition anywhere near the normal. The delicacy of the structure as a whole and in fact of all the organs, very much in- creases the chance of injury and even when great care is used, the tissues are generally somewhat torn or out of shape. The integu- ment is so easily ruptured that often only the weakest anesthetizing fluids can be used, and then a complete quiet is not obtained. Then also the species which reproduce by pudding very easily break off from the growing divisions and are likely to be mutilated. As a consequence of this, especial boa iekear and care must be used in
the handling and control.
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13 FIELD NOTES
During the past two years, collections have been made in some eighty streams and ponds. About fifty places have been visit ed only once, a number of others two or three times, while from a few collections were made every few days for several months. The immediate surroundings, the state of the weather, the condition of the water, all vary to a greater or less degree. There were grad- ations from a sandy barren flat to a wooded hillside, from a hot July day to the intense cold of mid-winter, with five feet of ice thickness, from a few quarts of thick muddy water to a stream the size of the largest river. The types of places investigated may be Summarized as streams, ponds, springs, and temporary mudholes.
The springs and puddles seem to be unfavorable for many of the smaller animal forms, except in a few instances, along the bluffs above the Mississippi, at intervals of one or two miles there are many springs flowing out from & more or less rugged hill- side forming Little gulches or marshy flats in their course of two or three hundred yards across the bottom land. The water is always clear altho in several instances there is quite a little sand washed out with the stream. The presence of the extra amount of moisture causes a great luxuriance in the nearby vegetation so that the little pools are completely hidden. In these pools and the
trickles €onnecting them, there are often many entomostraca and
insect larvae but very little or no filamentous algae to form a
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14 lurking place for voracious species. The food supply is also nearly
nothing, as protozoa, rotifers, and small crustaceans are absent. The hardness of the spring water coupled with the almost lack of
organic matter explains the absence of turbellarian species in such
Situations. In one exception, where the location has made it pos- sible and where the spring furnishes sufficient water to make a fairly permanent little pond, both the plant and animal forms have a@ chance to develop and are present in abundance. Here Stenostompm may be found in great numbers. If puddles are made by the overflow from some stream
or larger pond, then the plant and animal forms present will be those of the main supply which have become marroned. They will
eke out an existence as long as conditions permit or will thrive if chance favors them. Thus in some years the rains are not so heavy as to violently stir up a pond, and then if the situation is partly protected from the drying power of the sun » the imprisoned fauna and flora may flourish thruout the season. ‘It is very likely that the general life-balance of such heterogeneous colonies may be changed, perhaps several times in a few weeks, with the result that the total fauna will vary. At one time, a single species may be vastly more abundant than even in its natural habitat and then at another time, very little later, it may be entirely absent. In many other puddles made from either a source of clear water or by
a heavy rain, aquatic insects will appear in twenty-four hours
and a little later many protozoans. If the water remains for some
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wt io ele W048 te bomen a odd te moxk obem te ere arivent “sh id om ind thongs dSbw m secon pi 7
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5" length of time so that filamentous algae have a chance to develop,
there will probably be also many small crustaceans and an abundance
of other life but no rhapdocoels. That is, species capable of
finding transportation thru the air may gain a foothold in ponds
| where other species unable to do this will not. This, perhaps,
explains first the presence of certain rhabdocoels in some mud=
holes and not in others of different origin yet alike in general
condition, and second the presence at one time and not at another.
The running water of streams and rivers does not produce
situations favorable to delicate free-swimming organisms. Thus
the type of turbellarian found in such places will be that capable
of finding @ sheltered and protected spot where there is also food
and oxygen. In the Rock river, at Milan, Illinois, where it flows
over six or eight miles of rocky bed, planarians find an ideal lo-
cation. On the under side of nearly all the stones Which project
up from the bottom or out into the water or which lie against each
other so that the underside is not buried, a number of specimens
will be clinging. The stones are more or less rough, covered with
tiny crevices which make good hiding places, the worm being almost
below the surface and thoroughly protected put still able to make
use of the swift current of fresh wager. Collections have been made
in several other localities upstream and within the limits of the
rocky bed, but no planarians were discovered.
A situation similar to the above is found in the Salt
Fork of the Sanganmon, at Homer, Illinois, where, for a distance of
io > Seviiiee: Wshooign jek tartt cca ahora ah hd vest oot B shoes Ni Su “Ue eae, antt aie dNT ator ILiv a bd ee afi SOR «tt a Secdotee seamed 40, BoNoROTG waa
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eudt \ ad Ltshano ari tne we ~oaed sseolion ot oSae iidaquad teds od Silw sarolg dows mk Longs satasth hock cate #3 eninlt | erate Joga Aeteose ny ‘bra bursd tone awolt gi ovedw otomeLiT .wediioe owas ‘Mook ont? ste agi faehi oo Bek? tosis’ dad cation: Ye: wo un dh inatosy doilw coders oft Le Voksen Xo ebke xahme mel Kimo tenbagt ad dosiiw ae seta ORs POR dup ca mod 3 ot r , oremboror Po vate s ,hesied son a) ania nanan os foiw heveven aot aeel «o etont wit ‘weno ott. raomta writing meow ats AOR aunhe boop, oxen vous 4 oma Gt ekshil. rete “Suse fodundeng gueren ban © Shes nosed ove enoisoeLion eae coon eka ents Lo wb geld anit ho onda | pbovevere lh eww.
ped. Thewater runs sluggishly everywhere except at one point,
and here there is always a swift current from the overflow of a
dam. This is an ideal locality and living upon the rocks over whic
the water is continually pouring are many planarians, the only ones
to be found either up or dom stream. The Sangammon, itself, is
another stream of this same type, generally slow-flowing with few
or no stones. Scattering planarians have been found clinging to
rocks at a place where there was a little fall and consequently a
swifter current for a short distance.
‘The larger rivers with sandy or muddy bottom have, as a
rule, a fairly even shore-line with few small coves or indentations
while a strong current generally keeps the banks washed clean of
any driftwood or riff-raff which might lodge masses of organic
debris and thus offer shelter to microscopic forms. On the side
of the river where the current is undermining and changing the
shore, no life of any sort is possible, but on the beach side, many
Clams, snails, and insect larvae find a a@ feeding ground. These,
however, are able to anchor themselves firmly in sand, while such
types as flatworms and small crustaceans cannot exist. Altho there
have been at different times many collections made by various
workers and at numerous points along the Mississippi, rhabdocoels
and planarians have not been reported. This absence seems to be
easily explained since the conditions in the river are vastly
different from those of any of its tributaries. Forms carrying on
‘sayin ets of sae i canes worteint om Mort
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17 a thriving existence a few yards up some smaller stream meet with
entirely new enemies and encounter a powerful current which will
quickly dash them to pieces upon entering this expanse of water.
In the main branches of the Iowa, a like situation pre»
vails, but here all along the course there are numerous small
ponds left by its very habitual and periodic overflow. This back~
water is generally protected by growths of willow and swamp maple,
and may receive enough drainage from surrounding fields to last
thruout the season. The plant and animal life is often very pro-
fuse and many Stenostomum forms have been taken at different times
from such ponds.
Another type of stream which often becomes a suitable
location for many microscopic species as well as larger forms, is
the artificial ditch or canal. Here generally the water flows
slowly and comparatively evenly, there is little danger of flood,
and many types gain a foothold. The Hennepin canal presénts con-
ditions father unique in thesé respects. The banks are riff-raffed
with rough stones which make numerous crevices, the shore line
being perfectly straight with never a break or an eddy to disturb
the calm. There is movement sufficient to prevent the water from
becoming stagnant but not sufficient to cause disturbance. The
stones are covered with fine algae, which forms an ideal feeding
ground. The larger crustaceans, predacious larvae, and even most
of the microscopic species find it a poor situation, so that the
rhabpdocoel enjoys an existence singularly free from enemies, tho
i TS i a a: a wr a Ve I
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on this same account the food supply is Limited almost entirely to protozoans. Altho not plentiful in numbers, these forms are seemingly in control at least along the edge.
The most nearly ideal conditions for rhabdocoel exist ence are those found in permanent ponds. Here the water is compar- atively quiet and the hunting grounds are sufficiently prolific.
In one such pond, eight collections have been made at intervals of from three to nine days, with essentially the same conditions and forms appearing each time. This was primarily a little stream racing thru an open valley protected by low hills on either side. The water is held back by an earthen dam to make a pool about thirty yards across, and with a depth of from two and one half feet in the middle. It is used chiefly for wading by the cattle in the pasture and is kept stirred into a thick muddy semi- fluid with little life of any sort. In direct contrast to this, below the dam for four hundred yards the water is clear, kept fres? by a little trickle coming thru the spillway, and filled with an abundance of animal and plant life. At first spreading out for one hundred yards and with a depth of three feet, it later in the summer shrinks to one half this size. The ground around is *mucky’ covered thruout the marshy portion with “Island Hay®, then there is a region of Carex and Juncus. These,in the first place, harbor number s of rea winged blackbirds, secondly, their rigidity and harshness serve to keep away disturbing cattle, thirdly, act as
a windbreak so that not even a ripple may disturb the surface.
|
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— pond. The water is more or less filled with masses of Nostoc, Spirogyra, and diatoms. The number of protozoans is very large, then,of larger types, as water beetles, dragon flies, snails frogs, etc., there is no lack. Members of the genus Stenostomun are abundant everywhere in water from the surface where they swim freely, from deeper portions more or less muddy, and clinging to water weed, which, when taken in quite drained, will show great
number 8. Out in the middle deeper portion, are large patches of
Nitella, most of it nearly covered with organic debris and harboring many specimens. Taken from different portions of the pond there are some half-dozen species.
Another pool where many rhabdocoel species thrived, is in all respects a marked contrast to the above. This is Beatty Lake, a little body of water unique in its surroundings and form- ation. It is situated at about the level of the Mississippi river, not more than five hundred yards back from the shore line and with the ground level between them not more than six or eight feet high. The side away from the river is bounded by a mound seventy five feet in height which bends around to the southward, forming a nearly perpendicular wall on that side. Toward the north, the sand slopes away gradually. Surrounded on all sides by barren sand, the pond is essentially a *hole*® with the bottom so near the river level that the water never seeps away, and with enough draining
in to prevent its drying up completely. On the west and south,
the wind is entirely shut off, while even on the north and east the
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20 ground is high ehough to prevent much of a ripple ever disturbing
the surface from that direction. There is almost no vegetation
within a hundred yards of the pond in any direction. This is
partly due to the blowing of the sand which covers everything. In
one place, the bush=-like branches can be seen, all that remains
unburied of three tall locust trees. The pond bottom is sandy,
very solid and smooth thruout. The banks slope very gradually into
the water. It is covered around the edge with a thin layer of
organic material deposited as the water Slowly recedes a little,
leaving some dead algae pehind. The water itself is quite clear,
from two to five feet deep, very warm at the surface and cold two
feet down. Tho used by cattle to some extent for drinking and
wading, the sand, when stirred up, quickly settles, leaving the
water as clear as ever. There are no rushes,or other plants of
this type, which reach up above the surface of the pond, so that
the broad expanse is uninterrupted. Near the shallow portions,
within the pond, aire great masses ofvery coarse Spirogyra, showing
very bright green against the sandy background. There are also
patches of Nitella, heavy and dense, and sheltering at least five
species of rhabdocoels, all active and well-developed specimens. In
the deeper portions are large clumps of water lilies and several
other flowering plants, such as arrowhead, and floating around at
the surface, sheets of Cladophora and others of the low algae.
Thus, while the plant life is very profuse, t he animal forms are
much fewer. There are, of course, many microscopic forms, but
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There are no frogs, clams, or snails,
larger types seem lacking.
no water beetles, and only a few dragon flies. Out on the banks,
a little sand toad is conmon together with four species of turtles
and a little sand lizard. Altogether, the conditions prevailing
seem to be ideal for several species of special interest tho not
so favorable for most others.
A rather surprising situation was that encountered in
an old boat anchored high and dry in a little clump of willows.
It was protected from the wind and open to the sun so that evapor-
ation would seem to have been rapid. However, the two or three
tubs of water which the boat contained must have been put there
two months before, at the time of high water, as there had been no
rain. The whole oat was nearly filled with three species of con-
jugating Spirogyra. It was very luxuriant and harbored copepods,
ostracods, diatoms, rotifers, and other lower algae. There were
no insect larvae, as might be expected, but many species of proto-
zoans and such simple organisms. There were rhabdocoels in abund-
ance, the ever present Stenostomum and two other species, all
thriving in their prison, a little world entirely isolated, but
perfect.
Thirty yards away from the old boat was a muddy pond
which well illustrates a different type of condition. Early in
June, the overflow flood-water spread out over a forty acre corn
field, much of it drained away and by the middle of July there was
only a depth of a few inches. For a rod back from the actual
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22 water edge, the ground was extremely mucky and soft down to a
depth of eighteen inches. There were very large patches of mud-
covered Nitella which seemed to be the only surviving species of
plant life, growing all along the shore and out to a depth of ten inches. The water was *thick® and black, with only a few animal forms, except in the case of protozoans which seemed to flourish. Stenostomum was the only rhabdocoel present and all the individuals
collected were very long and slender. In a situation absolutely
prohibitive for most species, the Stenostomum was almost the only
form above the Brotozoa which could carry on its existence. Another very different type of pond are those of the
United States Fish Commission. They are artificial in their origin and are always under control and present data interesting in comparison with natural conditions. The methods used to wipe out one species and further the existence of another throw much light upon the forces in nature which bring about these same results. These ponds are either cement lined or have a simple mud bottom. The depth and shape vary. Some are shallow, mere tanks with a smooth bottom, while others are leng and narrow with a graded bottan giving half a dozen different depths. Often a number of half-par- titions supply lurking places dark and secluded. The unlined ponds are generally open and proad with a depth varying evenly up to eight feet. The small tanks are about three by eight feet, while the largest ponds will cover an acre of ground. The water is
supplied from a common reservoir, filled from the river. There is
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25
always an intake and outlet thru which is supplied a constant and
The loss by evaporation is thus supplied, the oxygen
steady flow.
content kept nearly standard, and the water constantly free from
The life conditions are much less complex than is
organic debris.
naturally the case, since either fish or clams are the only large
species present. The vast number of microscopic forms have found
their way accidentally, and flourish because the situation is favor
able. All of the ponds contain a larger or smaller amount of
filamentous algae, water weed, and lower forms of plant life. This
helps to furnish a never-ending supply of oxygen and a hiding place
for huge communities of entomostracans and the like. There is no
possibility of a sudden change in the several life factors, 1.¢€.,
the conditions are constant and steady, a situation which is ideal
for all sorts of types and makes the number of species very large.
Even during the winter, down under the ice in the deeper parts,
the stream of warm intake makes possible a continuance of almost
summer conditions, and consequently there is not the wholesale
killing off that generally follows the fall drop in temperature.
Thus generation follows generation without a break, right through
the coldest months. This is so much the case that every second
season most of the ponds are drained and allowed to lie frozen and
dry for several months in order to check the enormous multipli-
cation of microscopic forms above the optimum for the species of
economic importance. The cement tanks are also emptied every fall
to prevent freezing, so that each spring the flora and fauna of
tht le
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wet avert 4ergs Sigoesssetoin io Secdcurnr tone “ott? = if : 2 ae 3
ie interne “etTage. io “teygrol « w2g3m00 Siar as to", 4
bs ; Mihi SPA tenyio To victwe Arttthet-event @ a dalam
on as opt? seme ott tyw ane ev teonctre Yea eer — yeosl ,OvOroR? CFLE Teiwwee ors a aie » nebiue . tc My feohl ai aon mide Coie 6 ,Vhoerte Anes jegzeReo -93s y PEL TEAe S. My hologe Lo Megan ot SHE ‘ib cogey to at 6 err, Yeqeeh- at? ah ool erly wb eb Seviiw og Uoriin
tO OOMBRMIS Moy B BLY. 8aGd, toa shetme? gone to m
tone Lotw att Yow ef wedi viirigugaeneo fre sod tii wn
: yy
SUI Moy al gots Eta’ wets ewottos widewag mais rae catyeroets Pegi aia 8 stuart. Be Nees aivlek fot gsolse radon “aoe fede Game odt ipsa of a2 int. thd ia ‘er cont ebb te Rane ta: iene: honkarh oa ebay’ iets Re : o4 tu ‘a Lay marCHeME IRS, end somo on nahn: a siforom
to dessoaqe end ot noatege sett weiter
24 very many ponds begins anew, and it is of interest to see the rapid
ity with which both animal and plant comnunities manage to take up their existence. Many other ponds, permanent and seeming to present con-
ditions suitable for large annual communities, are more or less
poor in such forms, and may also be said to be dead water, and many
which contain various species will not show planarians or rhabdo- coels. Perhaps the most influential factor in this poverty of fauna is the constant agitation of the water, which, when coupled with a variation in the amount, is sufficient to prevent much life. Then, too, many species are s0 retiring in their habits and spend 80 much of their lives hidden away that they escape notice even
tho they are often present. Such is probably the case with many of
the creeping rhabdocoels.
Wit
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JPL a i eo Lo “pone: Bie ain viele 4 Liv ancoage aopitay, ives Ialineulias daca 638
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2 _ stLoopohdad%
t ik
BIOLOGY
Any study of biologic conditions is att he outset super- ficial, and only the most general conclusions can be ventured. Definite and positive statements are to be questioned since s0 vast a number of factors is concerned, and it is often an impossibility to know or control nearly all of them. Consequently, many obser- vations are qualified and results are guardedly and hesitatingly set forth. In studying any pond or stream, there are always many details of life habit which present themselves conspicuously, and many of the influences Which bring about certain effects can be very clearly recognized. 7
Perhaps one of the most noticeable reactions is that to the amount of oxygen. For altho supplied with no tissue or organ by which to make direct use of oxygen or by which to effect an exchange of carbon dioxide, the Turbellaria are all quite sen- sitive to the presence or absence of either. The processes of respiration are carried on thru the skin, the parenchyma, and even thru the general cells of the body itself which are in direct ieienicetion with the surrounding water. Thus, altho the amount of oxygen necessary is infinitesimal, there is no reserve store, so that there must be @ very constant source. In aquaria, when there begins to be only a slight overlodding with carbon dioxide, many
individuals can be seen making their way to the top where there is
a layer of fresh water. Oftentimes this seems to be the only
> oie” Te ye ioe deiner - <A a + ads ; ri ae, Ae
Lowuney ed med aah teess shai. od arts: Wie
ee
ct Pe le * fesv 08 eonte Senottasup ed ot ete ee | rs aA “ -
> ‘ 4 PD ie ha iriigiavegal me mavto af yi bas _beirsebane at omiog, | pa
~conde vnew ,vivnereeracd modo to Lie Yieeae toe YIantiu Diet fan ylhebusip, one t i Lier bas holdt ; (Aem yaw iSs, 818 SteNy ~oceisa wo Mog Yee testi his ,“lshowoiganos giv iene! iomesuy, domiw Fide 4
at nae evo es ho niazsen ‘soda waar doidw sooner
‘ ‘ae
hon lagoowtd
nit? wt gniadiens alaasos de ; jean of? Zo ono aque © quagit on diin Hethigne aisle “10% ‘amarko to Pe Vosite OF pide us do near Ie dev soa%lB exam ot +O “88 ation fe sia aiiatitodiuy ode biKoLb nodtes +9 Yo aoeteooty edt .5 WitLe 2© Soweaas we saiivasitle ‘ : reve bits ,emucions ing ada ite ont wai? ae pees ou
$ OBER ni ote foidw YieeJs2 uBog ed? Xo aitao
Zo tacome ond ote in Cent? ot stetky gat honorsie ang atiw | | o% ,eiote GyiodeT on ed ernits. ienbade haf tad, et “ ve ead? vuecdw Ce cae spphacd tagdenos VON od et % Creo " oh Kak! Mod 40 cit key guiribelseve sight a “seliaa
ber | Le i
ei used oe oe ads OF Yew abn i mgs bey
a
“kee Oita ont ad alas star tenlsensro at é
26
method of driving certain species out from their hiding places.
They are likely to remain near the top for days, staying quiet near
the edge or very slowly gliding about just beneath the surface.
Sometimes around the edge of the tank they will crowd up into the
little film of water held by capillarity above the general surface.
In balanced aquaria, on the other hand, large numbers are often
hard to find, since even the deeper portions will be perfectly
fresh. If, then, for any reason the balance is suddenly lost, up
to the top will come several species. Some forms are habitually
swimming free, and are much of the time to be found creeping over
the surface or exploring pretty thoroughly the deeper regions, but
under conditions of lack of oxygen, they will remain constantly in
the uppermost water, avoiding the foul depths. Under normal con-
Gitions, many species find their most suitable habitat entangled in
a mass of angae or creeping over bits of weed, probably as much for
the supply of oxygen and consequent purer water as for a hiding
This last conclusion is evident since in those pools where
place.
there is little plant life, all the specimens present will be found
in close proximity to whatever bits of green algae there are, in
the same way that any animal frantically clings to its last source
of oxygen.
Planarians which live in vastly different locations
from the above seem just as sensitive, for even tho their habitat
is running water, not all parts of a stream are equally favorable.
For example, the pebbles and rocks in sheltered, quiet pools
i i PA he i ii er Lis LC oa La), um , “i ta us ap! rey! i r ; . y ; : 1 , : : 0 raid gal xt ee en i i a bd or lm = ren pnts ra: by ne " mie ates : ; f a. ‘P A Sto, Gee he » a i Ae ee dh AY i . , a dé = Cee if aie AM
i goons TY ykire ‘wie? iene $2i¢i “aakoogh inves ah
© Tet ‘oiup @btiede Soh eet got arly TASH ahawort ot 3 va
|) pas Lrse aaa to rwresd des, sue 2 ithht fy ehusde now ih) a
Dont odet Ge Seons Lied Meade sree eas #0 agbe we 2 i a | font Larraaiea a? syvode yakwattibeso \ ‘eu A Sod vedi ta:
“Jn eS, 4
1 wetio sts erodadn oR teh (amd tesco aft to at cea
piivezt wee ed Lily enmoivver wsteah ats neve. eos
' eo _— é, : . j ae a : ur i Jeot ViwShee. &i eonabed writ sodsed vie SO) (eE il U / hi (itautigad 248 eprich enw wreleeygs feusyee omoo Lem we
: LoVe ith GOL faunot oo OF tuts of) To sonw e464 Gas 99" . Sixt ,Anocpet weqoeh aty vitqwo ued? «song grtsolics. tee Ad
i mi vliastaneo atemier Iffw yeds .cemico te xAoal te anohag
“oo Leon had eadyed, Luc? s)13
~
izeioya , Tia ry - (mt botnnntiwe taaliet ekiatline jaom sist? ttt asloaga %
962 dovum és vino, Boon to esid sro gniqeuet 4% ORR ¢
‘ witlOledl 8 SOL 88 “toda win JESU PRR TOO base caggatoe te : = : i.
4} now alooq Seadt mi eomie sneahive of molanionao geek
base? od I[iiw tase aimerores ofy-ile steal aRay oleh ha ; en
> a
rx .OR yevets omy ts moo" ne aiid “ove dute at Yi
ance Jeak adk oF ‘tamkto ‘elise. sted Lariat te Such
enol saank : troseehen idasy a awh s aotetw orto wands “a
det ident “tl orig ons nove aot corte inaa | a6 at wees Ta yi; ay +S ifarovel tLleape onhe wwehae g oe ao ita tom mie P
nt An atvoy twde aati at are Ja “aenstog, lg
Pig ie ‘4
ein ond ye pe 1 ey ha eid Flig te AES (950, |
27
will show no specimens even tho the food is ample. If, however,
at any point a little current passes thru, thus raising the oxygen
content, there will be at least a few individuals. Out in the middle
of the river, on the contrary, where the flow is exceedingly swift,
making a boiling, seething torrent as it tumbles over stones, the
oxygen content will be greater. Here the number of individuals
in a given area is limited only by ‘standing room*, even dead clam
shells and bits of wood being entirely covered. Thus it seems that
in respect to their use of oxygen the turbellarians are not essentia
ly different from other higher phyla.
All the turbellarians are,to some extent at least, sen-
sitive to light, but they react toward it in very different ways,
80 that no general statement can be given. The presence or absence
of eyes cannot be taken as the main factor in this response, for
altho the eyes are primarily light detecting organs, species in
which they do not occur may possess the ability to distinguish
between light and darkness. The planarians and rhabdocoels live
under such different conditions that a difference in reaction is to
be expected.
The planarians are definitely and obviously negative in
their response both to diffuse and localized light. In three species,
common to this region, the eyes are large and well-developed.
The animals live ordinarily under stones or in the depths of algal
masses where a good deal of precision in their reaction is necessary
If placed in a large open dish, they will investigate very thor-
we
isvowedt! ae, se ar boot orl wg hs ocaaing ‘Hyete cht: Qe, eu gts nouneg oe:
; ent corte, ool Se Aataghivebbict wot « re 4M wk | | SUhia gedit: ak wait eee arventi a eke arts ‘was a 46yo Golenns 23 ae ayonnbe g , | eienbivehed: Be workmin oie srt 1980 od ste
vo Riga mre LOOT ort Merts * ny 4 <ia0 Bat bint Bi
7
Be
s
tots anon DA BMET ahorsyen yLosd tem Ariivd bow tq: Meignases Pha ete eartnealfedsay!) uA maaan 10. o8n nila abate wtaia wai ro ots
108 .tenek Je eayano ome Ot ota vadabLagmed ota oe ete 1 ANYELD aiwer ab #t Seewas 2oset Youd pend r r poroada Na OOmet a 7) ae rea wef ago a Is “ot aIOee tT OLN al Goto re hcead aehS a8 {tad OF |
si seloege yearned gritos: at) ties yt dncmeikeer aug)
the iiyetatir O94. Lila art onerens ven min bO- 200 ,
avit alooophiyads tas saci haus Eat oy? sanenad: bien 4
et? ef sve Jose ot Al Borstettih «. Irae. mot athens
at ovttanen dlounnede iia “gro cat os mronaei si
Motoege sew me, ates hex tinoot bas: ved hth or ae -aqotoyobm sien ow gpryed ‘oth enigg oni OLS
me We adaqee ont at bal bok: ube “eis vt i pa ° a: =
a nna pti es Renate “bods nt cts 36h _ ya! th
oughly every part and invariably come to rest at the point of greatest shadow. Their ability to estimate the size and density of the shadow is rather keen, since they seem able to distinguish even small dradations. Another factor which is perhaps to be correlated with the perfection of eyes is the relative amount of color. The pigment which here varies in amount with light and
dark locations, is not present,at least to any degree, in forms which do not possess eyes, and it is not an unreasonable conclusion that color and eyes have evolved together.
The rhabdocoels have a more variable habitat and are not capable of as exact a response as the planarians, altho some species possess as highly developed eyes. The color has no direct connection, as for instance Strongylostoma, a form which has relativ ely very large eyes but possesses no pigment. This is also the condition in several Dalyells. The members of these two genera are positively heliotropic, except when the light is intensely localized. The genus Stenostomun, on the other hand, is without eyes or pigment, and has a negative response to light, be it strong ot weak. ‘These forms do not habitually frequent deep, shaded places put rather a dimly lighted Situation. This fact perhaps explains the rather general reaction, and their habit of being content with merely the less lighted regions. This habit, however, is constant, tho in just what way the light is sensed is hard to understand.
As a whole, the genus Stenostomum is very simple in structure, all
of the reactions being general rather than precise, and this re-
= ¥ (ii a> {2 beeen sl Adee araegur.
to dnlog edd ga si ob Goo 5 ‘ytetade % avis
ej tamed bee. ond ® orf) otmmties, od’ vitlioe ‘age, aM
it
leiigertgeth of Odds mae gortt onde ene tense. a wo + aderldeg et cote ~odue swrtoma of ioteabat bid | ¢ A
| c. ) Snuome owitaies edt ef eene Bo molLtoot1ay. art Atk Mi
s Sfgdi dolw tnuome at wefasy otod ciotete tebaghey 3 : “oe chat ,@0°o0@b ws of teaol j8,!aa8et Jon 4. oe | 4 i = .
’ - ' hw, - ‘ i” \ i. ¥ : ba ,
i nosentones eidsagesanw of Jon. af oi ire ave vasseod IE y
stad2onoy Sevieve oved seave faa
O31 Goes sevidedn eléalusy com @ evil, eLleodetdady eaioe
4 tt i Py > 4 cat am > nh 4 . as > — ‘ 1S a ve Li 7] a ie 2c ler of 1 < te Lv 4 7s «© J are? 4 2 i 7 } yp" : P Gur & Prt As Is 2 ‘ett a6 « Ve. fy NM ji { aw ey HI , i oan @
PWitaion set dotdw wel @ emodaciIvamowl oonepeit 192
J ¢ wal ; ie 4 of Tn siavemtia on POLauUakc $ rey “2aVo ah) J q oe : Ag Se oy, ows seeds to enotouem eff. sadleyind inteves ree
loeneind al Idpil edd) aedw 2qeare,- ,otqo1te. fer!
uotttiv al fred: wetvo oat no we@enteone 34, eunag. ud? Tmnotse J) of tat. of eamogeet evitepen sent has nai manala beaede (qeeb $eraty ant yf Lews tonal ton 6b toriol sent;
Saige aqar: VE spat att iach ety ot aca bath 8
ei ae 5 ey ii e j asin somsnoo gale Xe) we hpi aipds: bee ewlsono7 texan 4 , at “a
trsianoo at .wovewod. tide weer \osehgees Pooyit ery 4 sioetatéeie oF Huet el beings et ight, etd re ts . Br
eae “ = » (in ,omtonig a nd 0 Signa aw eh .
3 AL ag
sot adctt alti oe tow) ‘pansteny |
29 sponse to light is the most definite of all.
The effect of temperature in any detailed or definite
way is very hard to ascertain, since it is of general influence,
having to do with large quantities of water rather than with any
very limited portion. In the broad sense, temperature is the main
inciting force which every season starts or retards the life pro-
cesses, and almost never in nature will it be found as a localized
stimulus. During the winter, the ice confines the cold to a layer at the surface and to some extent limits and restricts the extent
of its influence. It acts somewhat as a blanket, preventing the
cold of the air from penetrating too deeply, so that beneath it a
vast deal of life continues thruout the year. It seems certain
that rhabdocoels remain in this layer of free water, which is, in
fact, their regular habitat, rather than hibernating in the moré protected bottom mud. Thruout the winter of 1916, collections
were made from a single pond every week. During January and Feb-
ruary, the Cladophora was dragged up thru a hole in the ice. Two or three species appeared in every haul, tho sometimes not in great number s. It is of course evident that myriads of individuals are killed by the cola every winter, especially since by far the most live in the region of the surface and are frozen. Those which are driven to deeper water carry on their existence, perhaps with not so much vigor, but nevertheless very successfully. Another factor which must be taken into consideration in drawing conclusions is
that, with the onset of cold, the manufacture of oxygen is cut off
{take ovkaeeaae Ries edt or 4 henry f 20- Oa ET ces nee at owoendaan te topes" | oomittad Lpsedey to @2 4f Sones Sealoebied br eal 0 ue tend? ete apa 26 buss ddinap oye’ stow |
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broke agilon ,Bi0£ Ye Sosnsy sett Feat sith Meee «<fe% Drtih uate ~ pi ii («+ eope weve brteg Shysise é@ mt ,a0lL off ase ofed a oat? coy. Sone aa svoryohndy ine ni ton sumiktense Git Dot Views wl Beynedde, sok: | otk eloubighint to eiedeunl see Lawdlive Béowe= ood a2 |
toon ol) AO? 46 aetlle eke apoue (MetnWe yaove ‘Tivo
on. Molde cect ~agseth ean ban veWtane et? to nolger ail ton, fete ih onete LK aod nO pws sos | nodoet sodvone : <WLheietean Nee. ‘anoded seven dane 10M tv
a: encdiuboto gak wah at ontario it none eta ma * ote tha et paca: eden ea bs bee (0 ots
30 and a large proportion of the descruction which occurs is a result
of the absence of oxygen and the presence of an increasing amount of carbon dioxide. As an interesting side light, ig artificial
ponds where thru the bottom there is a constant stream of pure
water all winter long, life continues with unabated vigor. This is, of course, due partly to the supply of oxygen, but the higher temperature also has much influence.
With the melting of the ice, in the spring, the relative
conditions in the water are entirely changed. The ponds lie open
to the warming influence of the sun and the response in many
species is very ready. Thus it is that most planarians and many rhabdocoels become sexually mature at this season. To a sreat
extent it is merely the change in temperature which incites greater
céllular activity. Those forms which do not have their reproduct- ive seasons at this time almost invariably go thru a period of very active budding or fragmentation which does not occur when the temperature is very low. Instances which well illustrate the power of heat are to be found in cases where a warm spring flows into a cold pond or stream. There, crowded into the water where the
temperature is high, will be myriads of animal forms. Among these,
planerians of all sizes are often very plentiful, while a few feet
away, beyond the reach of warmth, there will be no specimens at all. The lowering of the temperature in the fall has two definite effects. First, it retards the life processes of many
species and, second, in a directly opposite way, it induces an
be da? dn Baek ame. oi er en i. Wi ay > ea re cae a | ry My Lf i if o iy Be a
$iceas a at Reo. no dit kcaanint
seal) if ' Ps 7 Tw py ' ’ x ve iets," :
megxe-to gol? ims oe aa oai«a site nd ah
Season arctienianicnat re TO onmagend indy: ‘tons
~Sonpo ri ok comm ead ocala
gad Te seetta tedames-a at ceoriomedsod. end wna 8 ‘ Pod pei oii? .wogtv Potednm dike weenbinos SEAL) wud nsityid of? tad segute he viggee eared elem
! | |
j
Movi. slo’ ott peckage oft eb gol ude to peldien ode any
*
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S4Vd an, eee kau doidw: ewmeswegess mi sqms{s ods vista " tonto ne: thet awit 264 ob doinw envé2 anotl .vrieiigg i 2c; DOL NENG Be MU oe vidtelsnvel saomla wines gcrtd te ¥ ere sortw “eno Som O6O Held ctitnrnergatt ww guided,
Hod ds eteweolht: flee Holvte asornatenl wot vuaey Bs
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.
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Soot wot n, ebeee Subsembty “eho santo etn spats fhe to :
Re ent epee a
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eran
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7
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cceleration in the growth of the sexual elements. The first instance is the more common and has been referred to above. The second is rather difficult to understand. There are perhaps two theories to be offered in explanation. One is that those rhando- coels which, in their primitive habitat, live in cold regions become sexually mature when the temperature comes the nearest to their ancestral condition. The other is that eggs which may develop slowly or lie dormant for some time if deposited in the fall, will be ready to begin a more rapid growth in the spring.
In the matter of food, the turbellarian is not fastid- ious. Many pieces of animal and plant material find their way bit by bit into the tiny and apparently inefficient mouth of the hungry hunters. Plant food seems to be second in choice, probably because the thick cellulose of its epidermis is too armor-like, is beyond the possibility of even receiving an impression from the delicate and jawless lips of these gentle feeders. Even the finest of the filamentous algae are themselves as large as many of t he rhabdo- coels and too stiff to pe managed, while the lower forms, such as the flagellate swarm- spores and the like, are as 4 general rule too swift and active to be caught alive. Even the planarians seem to prefer amore easily assimilated food. When, however, algal cell walls are broken down, so that the inclosed cytoplasmic content bécomes available, either free in the water or adhering to its original position, then it is greedily sucked up by almost any
species. As soon as any of the lower plant forms begin to dis-
ii we a a, Le Pion P| Puce : - - ari a
ee
o ar
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i) SATE epi 6 trigon.
4 awl ax nt vik sseeenge? : shaped ovobate es ) aduortan sec ne “DOSES CONE 1 HOT ek ime so Sago mt pesto! ae nokges Lod ad oeks. dws dha: av kta sxlrwets oil
4 CROSS PO ee Bey re at? | seine arse vii
loveb vem dottw @gao sett af weet $e > ort w@tithaoe ) — z P ' ae | oe p) Woms hevlLaouph ii gett sqgoe “El Adee se i, -; | 7 ’ i ayet tw ms) Hr / wr on Peete 5 igay Soin & nse ry | 4 : ; :
“W470 ton el Matsetiodg’ oft boat Lo daehandt otis j j = v ¥ ‘tote Oath Intieion onely tine tantne Io vepekal FE s
1 ¥Nerin’ ont To Adem teolettvont iivaoweye het vert eee
h @anaood Liason wolorls mh Look va oc eaebe rest simaitaln ' wroyved al - aki tnuntun ee ei ahirwbiqe a it Te ono Sn Sita) ‘i tant Ul wid mot mote mrt tend rus nntw? aoa nove To var wt Lo teeal® arte rel a®ifnhoet okra, maori! to nh tt ‘ ~ltets ae ee be ection Oe enynine tf a) corr fommeldy out ong ieee i } ee fom tora & ges wuts OLarte neem: 64 08 Khisa oof ; oo7 blue 72 nooigee ue, Oe eee etd fins pancige- “SR ay (o0 napa agra ipia Sa hd oe grea ta Siquse ed oJ masa H {loo Lage ,wevewod sara ‘Bote Gorse tisiees viteeo. | 3989 904)" othmalqoaye Seinoont. od: tet, colton
ett o¢ paste oe sweatin cn owt “eene i
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is Aiimaaal ape ie %
| integrate, then they become a probable food supply.
The obtaining of animal food is somewhat more difficult, gince only the soft parts can be used. The entomostracans, rotifers, and such types, furnish large amounts of food as soon as the indi- vidual dies, but they are seldom attacked when alive. In one in- stance, only, has a rhabdocoel been seen in an attempt on the life of a rotifer. For five minutes they struggled, but the rotifer held its ground and the rhabdocoel finally left. The chitinous shield of small crustaceans armed with spines or other projections is formidable, but as soon as the segnents of the body thru dis- integration pegin to fall apart, then it is possible for the rhab- docoel to crawl inside and, thus protected, clean out the soft parts at its leisure. Protozoa are probably the nearest ideal food
because their protoplasm is generally not so thoroughly covered as
to be inaccessible and because they are common everywhere. In
those species where a calcareous shell is secreted, the rhabdocoel swallows the whole, digests out the protoplasm, and then ejects the hard parts. The planarians, tho often dependent for their food on disintegratea fine organic debris, yet when the opportunity offers make the most stupendous efforts to obtain the flesh of higher animal forms.
As a whole, the turbellarians are scavengers, living generally upon pits of disintegrating organic matter. In the general Life constituency of a pond community, they play an importe
ant part, constantly searching out and devouring particles which
ut
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t : ee x la
aifeq ice. of} tuo peptic ghovos!ory .eudty tan ehteal
Seton. nana tey Wants ethane miele’ ts. Damour”
of 7 Pres Ae;
a hike
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asi fe. a a
; Pa “ ¥ | we
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/ le '
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-1i oro of .avikfa wore Betoetoe inert lipns ovum vont aa r ‘PILL ocd go IgpeTE 4 aD toaR need floocohialy & a eat ‘
\.
LirOt ott Ios) be Lagiats yerts nosortm evil sof, aucerkitne oat tte (hfe? lsocokiats- et? tok 6 hpoigoplosyg tete 10 Bomtge tite heaiuet anbecetisw fi =B 57>. dwt t siti oni? ko SL Wagee Ol Be AES Se ad
it Of? “Ot obilmewyoet dx cont. .iuye List o3 ? iin
HoOoL Lapbs Mewes: ah yisadew os8 sosciond
de aoueveo ydrip@etiods os ton yilorainuy, @2 mesigqolows, te ri | Pi artwetees. Mons. Gun. verts etomoyd het. OAT sae
faccukjert? ost , hecedoer ae. Liars, apsategietp a reile
uPoStS medy Ama yreakygesety aris cio etageth etonte nhact “368 Sma brnoqgek nagho eds eel tereig aff, .
vlinulteaplo add ah dey 85M OD Gira. Set derernyeds :
to featt das ee
cliwil 1S TOD HOVERS ote eieninpi locus ack. - deat a aA) a
oil? 1h Rotten bhp gaborgocmtedy: Ye. weke cou :
CL a ea
oink 2b oper acide ete o%
i‘ mT | ai F 7 2 : ; : a a td bag
| | / |
33 might later be a source of bacterial growth. The smaller rhabdo-
coels can be found in great numbers, incessantly hunting thru the mazes of algae for dead crustaceans, etc., or burrowing and worming their way thru the loose earth-like masses on the surface of the bottom. Here they find what is left of myriads of protozoans and also other material either plant or animal which they speedily devowr Ainmals with feeding habits such as these would seem afays to have more than a sufficiency of food supply at hand. But this is not always the case. Under special conditions, other worms or larger species may keep the sources of disintegrating matte completely used up, or masses of debris may be entirely washed away to such an extent that a whole pond is cleqned of its food content. Under such conditions, the turbellarian does not die immediately. It goes thru a process of starvation so slow as to be almost unnoticeable. The individuals become thinner and smaller, and in some species may gradually shrink until they are no more than one- fifteenth their original size, at the same time becoming almost transparent in color. This explains the immense amount of variation in size ofadult forms, the individual dimensions depend- ing very directly upon the food taken. Planarians have been kept for eight months in clear water without food. The result was that at the end of the time they were still perfect individuals tho ex- tremely small. Thus it seems that the food plays a very important part in the general appearance of most species.
The enemies of the turbellariansare few. Altho such
|
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aah EX ay Wt ance lord Yo: etal To wrod ai eke habt idk oe ek a 4
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fet , band te viene Beok To Wormloryive © gay Sim 8
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iG fon eso Megtaliogage afl moisten ere
ei of 63 wold of wekvaviezd To. deeoos, & ult eeoy 2 ‘oftane Drie. Tanctat emoned afeuhiviinl aT +9 (CRIS LNG Sic Ont Sale wort Sikdem agate Vifadip wy ~sen delosqe’ meet abad ‘omit ame off Ja, S754 torial so warts dinses?
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Smit ase tiswon pet sbi swede tw’ G0 yaots cod econ i
34 delicate animals are evidently almost entirely defenseless, they
manage to carry on a fairly free and unhanpered existence. The smaller species spend much of their time swimming slowly out in
open water where they encounter almost all the other inhabitants.
It is especially noticeable in aquaria where many species collect
at the surface or towards the light that the rhabdocoels or planerians mingle constantly with the others, crawling over them and around them in the most unconcerned manner. And often two or three individuals will collide with each other without the slightes inconvenience or apparent fear. This is easily explained in the case of the planariens which are enormous compared with the tiny crustaceans, but the rkabdocoels are so nearly the size of the other common types that they woGld sea@a possible prey. However, a number of times rhabdocoels have been found gliding directly thru, between the valves of an ostracod unharmed,or resting con- tentedly under the carapace edge of some cladoceran.
This situation may partially be due to the fact that the crustaceans, themselves, habitually live upon disintegrating material and are not likely to attack living forms. Then, some of the rhabdocoel species possess nematocysts which would make them not only unfit for food but also rather well protected from most enemies. Others which do not possess stinging cells have especiall developed dermal rhabdites in very great numbers. While these are not weapons of defense, they probably render the individuals un=
- th th) Sar } ait bea Feet gle idee fetta re oe ut a Sty ws |. woapee ee bunkeniciy pat ook ea e “0
it ri s00 Chee gakietion: gat s “batts 2 tose haus L vite idee) seddor ed Bip Secuite selauoone ‘cat
, scolloy epiodya Yen averh shusupy at pidenotson es Yo @lsonoftagin add terie oeQ dd ont eiriww0d ‘e 1 TOVS ie BIO Ort Seiw eisnetenon ef
—
ows tetie bok .ieaeen Rerrreanconn teem ect a) meded
= Se
Pan? ifs ore “tuottiu sartso Mawe rtiw eb iioo LIlitw alaubs | vf?! ad honteline visege ah eist .1e02 TOMAG YS oO ag Yass edt ite Semagnee enoRMoW ots io.etey anes ince lg 4 ifs to sale ene ybiaese CE ate pisncetided etd. or . .tevaver ewig Gidistoy sees Hic yest Salt BeQys . ~20 yesdt dy Diaigt sed eves siacvohdads ape ‘ “100 Heliees Oo heeringgn! Soup ac ac Te eovlar. oft ae etsnohelo tae bo onde enpedetmo outa ohne al : imi? jont aff of pul os viilabiueg vem cofisvaesie gine a iiienmetaleks smog oe Viteue tial. .cobtnemodts. nner Bs to age nod? .6qhOk waives Meatge 0d RSet. 36m oa Bee Se ofan bisePg dm Sehr yn od arate nehesog getooeqe Loot i Res
’ soon me hesostorg) Liew rortse oe la Jud Aco? sot oe. oat
fisth ove ewe ellen pasgatse azeoveg ton ob oe ci
ipa oesds og ere Jao rw Mat ‘ts i ae
a4 y =i ahendd vets O27 cee iad bad. ort . ry f ra. ¥ ay i PAA Veg ein aA. eee © aes a F bp eees a eS: Ve - o f
. - —— eo ‘ : had A ae oe, ee) hd
Perhaps the most effective method of protection is the general habit of retiring to well-guarded situations. The large
planarian lying flat on the underside of some rough stone is in a
feirly safe place, where few species are capable of dislodging it.
The rhabdocoel hunts in some mass of alga where, at the same time, it is completely hidden from many large forms. If, however, it encounters an enemy of any sort, the rapidity with which it can
contract enables it to disappear.
p i 1 é PACTS 2 PE, AER wT ron ‘atthe a SSR A a a ae aie Ge an Nt 6 ¥ ak ve i ) a
sy 7 ots "] 12 Le sy aay ovieeeNeed
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Part II, MORPHOLOGY
Sees EAone were Pr ‘tban oe Sight Tae., 7 ;
re peentiful t
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| | ’.
MDONCHYAOM 427 duet
DETAILED MORPHOLOGY, Strongylostoma rosaceun
-
Introduction Specimens were first seen during the early part of
November, 1916, in the ponds at the United States Biological Sta-
tion at Fairport, Iowa. They appeared together with other rhab- docoel species, both swimming free in the water and also coming out from masses of algae and water weed which were dragged up from the sides and pottom of the ponds. They were present in larger or smaller numbers in all the collections made during the next three months. Individuals of this species were easily recognized by the rapidity of their movements thru the water and by their habit of launching out openly rather than crawling over the sides of the aquariua on the plants. They were frequent in most of the ponds and the reservoir which supplied them, but in certain places where conditions seemed espécially favorable they were very abundant. Such conditions were, in general, a large amount of filamentous algae rather than the coarser water weeds, a depth of water of not more than eight feet, and as might perhaps seem reasonable they were more plentiful in ponds where there were few fish.
These forms are of especial interest for several rea-
sons. Both color and preciseness of structural plan are striking in intensity and definiteness. Among the more common rhabdocoels
the color is nearly lacking or at least dull and varying with the
to fe ‘thwe erie gerd = oes! aw. | sega Bile il eects pas in mie ts anaeg ete oe A | “aris, Meta. iow “eri dee? Bosaegys ant «,en% f
UsOOE ‘te hos water ott si sort piiemive: cyod wont noygets eeq itodtte Boow ~otow fed oeele to Yo iomtet. fi pine ey yardy .ebneq oa tec netsod: Le yest). RBM svt AnANS Ghanian eno lcoel Loo evil . J Le tk i
f a
at? UC foutagouws “lleas vite, nobvecs side ta & Isubiy, , a ; , -. _ to timed wert ve fies wolew erit wrt ade: Baccus ain
st t%o abbli 68 aeeo itl iveats wens seagen Yiaoge : . . . io efincogq oft To deem al dompest stew sett Fat seca outs a ‘etarty eeuinity tlettes di cot woods heliggoe uiointes he Jjiotiotis 4iey.easy yets atu eueryes il laks8ees bowed | necro Ll Be tices saad: P fpr, fi Geen | aie he To “ei Lo qub as DVEW 192 BF 19e hoe ons cats Seg vers okismeanert 5H | gpa dete tn ae Bae seats 1agiom 13 wie aren sane irate abawa es srranetg 70" Cub Pengd apt tunioirent Lnbongue 10 ou enn peont | sti e COR one ong Lassid oon 8 sa stent baal vale § R20 ORT sehest Pao ‘oat aon
ont side wry taeie boa Lon, ened; eth 50. 3
37 surrounding conditions from a transparent white to an opaque gray-
green. In comparison with such fresh-water types, these specimens are gorgeous, for even tho obscured by muddy water the clear deli- cate pink is noteworthy, and makes them stand out sharply against the greenish background, easily distinguishable from all other animal species. While most rhabdocoels and even many Turbellaria are fairly simple structurally, in these the several organic sys- tems are clear-cut and more completely developed.
“Though occurring in large numbers in these special ponds, they have not been found in other ponds in this region, and members of this same genus have been reported from only three localities in this country. Altho they are probably present in many places and will be reported at some time, they are evidently not at all commonly living in the fresh water mud holes of the Mississippi valley.
| The fact that in water under the ice the number of individuals is large and that the period of sexual maturity is during mid-winter, may be correlated with the northern habitat of related species. In a number of rather widely separated regions
in northern Europe, numbers of this genus have been described, and
altogether it seems to ve a cold-léving form.
Special Technique Specimens were taken from the ponds in pails of water in the common way, and then, one by one, removed with a pipette to
small watch glasses or to a slide. For study alive, they with-
aa it 4 anne ee log "4 GEO) = #) iP sy Ty Geet ny oh wa
i g, cx ago ate Oh Rie, TReiaeNs amt 2 wt t000 & wets seg rose cetmertt cn a LEE “a vito ko Oph Madge wants ef o-ssbeiip, tle rh we — bri 5 , fms ite THO brbige wert s o eaten frees caisrenecon 8 ~gtea 208 mort o detect tivyied de Ly etn tc z |
ve oy ee
nine l sodas ohn ows hire etenmenanae saae onan “ews ohemiaie oboe ort? aciegts itd ‘<del st ey sete level viet fgmoe anon Dna teo~4
frioege seen? sk ered eguwet ct gelnwete dpoodd ; >)
*
7, [3
sort? \ytoo age Abssoge BY pee ewe aves omen aid te
olnes ele sit saith ‘goreo rl Boe? ofbe fort vag
ii jennie ibdattorn ome Yorts oo ta a VET SUIOD winds ate ispohive ote Wet? coi? enoe ga Iedeogen od iilby haae
ofs ‘Lo ap Lod! Ain setew meet off ni palvil Droog
od kaw be LO *spclunsty, ora ‘pol ang ain Yedew mt tadd seek ont”
wh sare: Lawman Ta Dod 194 ect! tarts has opin S gi” Seige orev ott few Dedakewoo: bd - Yam - eon ancikyen beanaqe yhebsw rage’ 26 seule ri) ail a Ann , hetiieoasy. ico: ent gmmy 2a? to wtonciasin esol a wnrnch paar | 2 wo on moon aa
“asew RO a Hag ae nate, cis tt nots ‘ame, sommtonce
OJ sea 9 Em Nene ote oe sed a “ow ne
38
stood the presence of the cover glass better than other forms,
since they do not easily or quickly break. Quince-seed jelly is
not practical as only an extremely thick solution has any effect
on the strong muscular movements. The best method is perhaps to
quiet them with a solution of cocaine followed by chloretone. They are very resistant to anything of this sort and it requires large
doses to produce a condition of quiet, and then disintegration is
liable to begin in a comparatively short time. When the animals
can be killed, corrosive acetic or colr corrosive solution used
directly after they have become quiet with the anesthetic will
cause little contraction. They can then be stained, cleared and
mounted in toto, and most of the organs will be fairly distinct. Sections were cut from four to eight micra in thickness and were stained in Ehrlich’s hematoxylin and erythrosin.
General
The length was taken when the animal was at the point
of greatest extension or at least when moving unhampered freely thru the water, so that both anterior and posterior tips were drawn out to rather acute points. There were a number of very small individuals which were probably juvenile and not shrunken in size, due bo lack of food. This seemed to be the case, since under star- vation conditions, there was very little shrinkage of body size, most of the change peing in relative amount of bulging in the in- testinal wall. Those specimens apparently adult will vary from 1.0
mm.e to 2.01 mn. in length, the average being within rather narrow
Corot whtte pals wee cen peaks “wiwoo eits te 2 Bo “Lot Reee shonin yeaa selyediip: ie eit cag eee | nisin so hee, \ SOMES oe Ke ted
?
cosrme@g of Hertam seed aT «0S nate vemt nem et’ | wonvdenodds Vt pewebie® ontands Yo aid toiten’ 2
sS ini esetpei oth as Ios éldy Lo witiiyae o¢
TOLTSVGRSMACEN NOMS Ta ~teinp To eo thio @ om
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hy TeteD
riot Gti om oe inminme ond nacs Gass €aw dégned oat z | Yioent bevtequeriant siiwuls reife Jaeol ts “46 iaeerK wash etow aqid tatsedacg Ine vobtedns ded +83 Bp. ileca vooev Lo nodtoriter B exny owertt jateted. Re
nie ot nestnuneia $e Boor efiepwut edetacrone srs ey velo Sete @omle . 6848 ed? eG od dameae ait toot 30 Ole bed to apesernute ekee1d ytev es enerts ; “stk ontd WE slesane: to thndan ov ite ten ink ‘gale pearre: a df oot vow it) GbE yltnbaagye cunntonge seo 3 wow ‘trig ita alae Sia a et “tenn aah ih
o. : et eee = a 3 a = z aap <=,
39 limits, 1.50 to 1.60 mm. The width is perhaps a little more diffi-
cult to Sompute, since it varies with physiological conditions, i.e., it depends upon the amount of food recently taken in and also stage of development of the reproductive organs. The limits of variation here are from 0.10 mm. to 0.35 MM., the average being 0.20 mm. to 0.35 MM. The greatest depth is very nearly the same as the greatest width, for altho the ventral surface is flat and the anterior part very low, the portion of the body posterior to the middle is very much elevated so that it is nearly cylindrical. Both the measurements of width and depth were t aken at a point slightly posterior to the pharynx.
The amounts of expansion and contraction are very great so that measurements mean little except in a general way. A significant detail withr espect to shape is the amount of food in the intestine, or at least the abundance of food at previous times. This correlation of nourishment supply with shape variation is the result of the flexibility of the assimilative cells. Under starvation conditions, they are very minute and occupy no appreci- able space in the body structure. When, however, the digestive sac is distended with nutrient material, these cells enlarge from five to ten times, and give the characteristic plump appearance to the animal as a whole. This species is especially contractile, so that it is able very quickly to accommodate itself to its surround- ings. Under the slightest disturbance or fright, it may be drawn
into an almost perfect sphere, the tips of the head and tail being
oF Ye sri ib stom Male @ eqatweq et Abie on, ott 0
ace rakiewe la tecsotrwie itin setssv pe finn n Sebet Chtwoe* Hock Yo. 2okeut = ir
| atinbs off. ange oybbstitore arte te tn Rolog syeiave ed , th O8 40 OF siti OL.6 ca pes eer 4
eran oft Uinetw yer. oi fscat geutaa%y ont ‘ i ber tOrk et aardase feigrey erit iene ot ated
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‘xe semele fs 62. 5t2
deem, Viv OMe apiddertr 1o frst oolesegee Zo eso: sfF ry
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A ive Faron e oi tosoxre alfiisl een eine ae
al Khoct te s¢arome odt -i cunie. ot toetee-4 agte toteb- a acorvesg Je Bool Lo ssnehroda ane taped 728 "te. mMlseisay ocerte dtiv vitiqua tnerviei ition Yo cobtefesi0sa8 ) “obit 02 06 evhielhimipse end to «at. Sheheot ens to otm sbosigde om TqNO0e Bes ethnky rey Se were a | sviteagrh ont. (Severn .cod¥ emboli vhed “edt ie ares ean alive efieo Stat. Toxine oie S108 Basile athe O¢ somersegge qeud¢ olde iel soauie ads arly Dre. ent ce ,olisoatinon vilosoeyae oi setoake “ia? prep re ehrusenure edt ot Wendt stabommcooe. os tn Eee OS Veet AL. gregh Sh "0 ponadeide tb a ph
only the merest knob-like projections on the surface. The limits of extension are very much narrower, since there is almost no
elongation possible and the animal, when moving, is always at its
greatest length. All the changes in shape are more marked in the
posterior middle part than anywhere else, the head almost const-
two rather knob-like protuberances which are just a little in
gradually bena outward again. As far back as the middle line (a
one-fourth narrows back rapidly to a Slightly blunt point. Al-
together, the shape is rather short and broad, with a triangular
anterior end and a pointed posterior tip.
pink, varies from a pale rose to a deep terra-cotta, but is always
of surprising brilliancy. This is apparent evento the naked eye,
the color, while the head region is white. Usually, it is the
} Cast that in most rhabdocoels there is very little if any tinge of
antly keeping its form. The term *head’ is used, since the anterior third of the body is conspicuously divided from the rest by a some- what narrower neck-like portion. The head,itself, is rather sharp- ly pointed in front, the angle made being about forty-five degrees. | A little farther back, on each side, the outline angles again form
|
front of the eyes. Back of the eyes, the neck constriction begins. This is merely a curving in of the body wall, which soon begins to
/ |
} point immediately posterior to the pharynx) the largest diameter is
reached, giving an appearance of general plumpness. The posterior
| ‘The color, which has already been stated as a delicate
as is also the fact that it is only the posterior part which bears
- : we meee.
he at heli etT _.eoRr igs earls eo aan kiceg at ous sete 9
on sogmkn Bt siete eons ow own foie yuev ou 1
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nt al Senin omen es siete out oegnaS ots ILA 6
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spunk 2 VG feet aty nett Rabiyib vlenousiganco ei. yo
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sic? cieue gefnaw ediidmo. afi .obta dome so ploed DR
ot aiset ls teu} ets dosrtw seonetodese4g com Aunines codtelitangs soem erie .coye ots Te Hore. .eovw
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6) enit ethbin eft €6 woe wit <A .ptege, StaWine et xotemals Jesu wel ons Caenrunic oft Gc? tolxsteog, yiedg soivotzog off .epenmppity intceg 10 ehunteoqge Ge
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te
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actio® & aa begmen, ened ante pant doidw ,tolos ont.
uvewin os tat A ssoo—ma tes ‘goat: 2 @t osot @laq A owt:
ve. fete afy ot eve Suereccs | ai aiat wvomsl Lit ad grinac ipice Jasy, sobyetsog ets Yino et 2. tedy tort onfd Ome ried - ba s od ah dS gehkeual, ehdw at nolger beer ers oLictw “<i
to ona wet Sh efessl yrow ei srpels ese ge arti soon at | i!
; 7
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i es A - 7 ional
color, since the epidermis is not at all pigmented. Such a char-
acteristic condition of the integument is found here, also, and
the special rose tint is lodged in another tissue. As a result of metabolic processes, there is produced a very clear, light reddish- orange oil, which, in the shape of globules, is stored in the out- side layer of the digestive tract wall, and, owing to the trans~ parency of the epidermis, is distinctly visible. for this reason, that part of the body in which the intestine is situated is also that which is highly colored, while the anterior end, into which it does not extend, remains clear. The variable condition of the digestive wall as a result of more or less plentiful sources of food, causes very evident changes in color and also in the limits to which the color extends. Consequently, when the lobes of the alimentary tract are fully extended and reach far anterior, t here will be some tint even in the head or,if there has been little or no food taken in for some time,then the whole animal will appear very light or almost white. Thus the color is in reality a by- product of the organic processes, rather than of especial intrin- sic significance. Epithelium
The integument is made up of a single layer of high columnar cells, in some portions carrying rhabdites and with a covering of cilia on the exterior. As a whole, it is an epi- thelium of the type found generally in the Turbellaria and varies
only in many minor details of appearance and structure.
ee nd
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stip? omy C2 Bhewe $ ,hre Od Poms ovioaayee “at
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These high columnar cells make the epidermis a con- spicuous body wall, a fact which is surprising on account of the extreme delicacy of the structure. Altho there is no cuticular layer, the outer boundary is very clear and distinct. This is due, not to thickness of material, but to compactness and a membrane- like toughness. The inner line of the epidermis is also well defin ed, tho not as dark and sharp as the outer portion. It is rein- forced by a very thin basement membrane which helps to make a firm base of attachment for the numerous strands of muscle cells.
Since almost the whole of the muscular system is, to a greater or less extent, connected with the integument, this layer must be able to withstand the stress of very nearly every contraction. The middle part, between these two clear boundary walls, is very trans-
parent, since the cross walls show but little, and for this rea-
gon the shape and size of the epithelial cells is difficult to ascer-
tain. ‘This fact offers some explanation for the ease and fre- quency with which the cells break apart. Most of the minor in- juries to the worm are tearings or breakings of this layer, which seems as easily healed again. It is probably of great advantage that the cells, pecause of their simple connection with each other, are able to repair an injury very quickly. Under conditions of injury, when the tension is released either entirely or only on one side, the cells very quickly become spheres, showing con- spicuously their primitive flexibility and lack of specializea
form. This flexibility is imperative when there is taken into
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consideration the demands made upon the epithelium in the way of sudden contraction and expansion. There is an incessant and con- stant change in the amount of strain brought to bear upon a single cell or group of cells. For this reason, either in a small por- tion or in the whole layer the shape and thickness do not remain the same for any length of time and except when perfectly quiet the thickness is not the same for any two parts of the body. Under some pressure, the high columnar cells become flat, almost scale- like, and the layers consequently very thin. In general, the average thickness ranges from forty to one-hundred micra.
The external surface of the entire body is covered with a compact coat of cilia. These are distributed very evenly, not being grouped. There is also little variation in size as they are not longer or larger even at the tips of the head and tail. There are no sensory pits with large cilia and those around the edge of the mouth are also of the same general dimension. I” shape they are slender spines with the base slightly larger than the up- per portion, which is drawn out to a long, fine point. The length averages near the epithelium thickness, with a diameter of 3 to 6 micra, and they appear as extremely fine transparent lines. The vibrations are very rapid and tho generally the waves of motion are from anterior to posterior, yet upon occasion they may be re- versed, Then, in different portions, the action may be at times en- tirely independent of the surrounding surface, continuing in some
portions long after the main part of the animal ts been killed.
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44 Other structures included, or at least connected, with
the integument are the rhabdites., They are arranged in two tracts in the anterior portion of the head. These are symmetrical and
are placed one on either side of the middle line in the dorsal
part of the parenchyma. The anterior half of each group is a broad, fan-shaped portion which extends to the very tip of the head, and pack and down on each side nearly to the level of the eyes. This central broad part as it runs posteriorly along the middle line toward the narrow neck-portion of the body becomes itselfvery slm@m- der, like the handle of a fan, and thus continues back between the eyes for a distance.fhenithe posterior third of the whole group becomes wider again to about one-half the width ofthe anterior fan, and bends outward away from the middle line, reaching almost to the sides of the body. The outer posterior edge is truncate
and straight, parallel with the side of the body. Another group of rhabdites much smaller than and lying directly ventral to the dorsal division runs backward at some distance ventral to the prain. It starts anteriorly near the tip of the head as a part of the dorsal fan-shaped group, and, bending ventrally, becomes very narrow just peneath the brain but broadens out again postere= ior to ite It ends apruptly under the extreme front end of the in- testine. The rhapdites which make up these groups are arranged in strands of very regularly placed célls, each containing a cluster of rather large rods. In the anterior part there are from twelve
to eighteen strands which narrow down to two or three,lying very
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45
close to one another thruout the middle division, then in the remainder of the group there are from five to six strands broaden- ing out a little. Each strand is composed off rom ten to thirty clusters of rods placed end to end so that the whole appears as a series of long lines.
The rhabdites or rods are surprisingly alike in size, Shape, and color. The average length in adult specimens is twelve micra, while the width or diameter is about two micra. When re- leased from pressure of the body, these measurements remained con~ Stant. The shape is a rather bluntly pointed spindle. Thruout most of the length,the diameter of the rod is the same, giving them the appearance of a rather long cylindrical pencil. The two ends are about equally pointed, and generally slightly curved or bent to fit the contour of the bundle. The color was almost a steel white, not at all transparent, but bright and clear, with the edge very distinct and black. They seemed like bits of metallic
rods sharp and hard, embedded in the most delicate tissue imagin-
able. There is always a rather constant number in each cell, eight,
nine, or ten, lying very closely packed in a solid ovoidal mass. The cell, itself, is quite large so that the rods occupy only the center and are surrounded by a large space filled with very finely granular protoplasm. These rod~pearing cells are situated either in the epithelium itself or in the parenchyma just beneath,as tho
they had been crowded there. The rods develop one at a time, right
in the cell, being differentiated,as it were, from the protoplasm.
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46 The rods in many instances lie with their points toward the sur-
face and under very slight pressure were discharged thru the out-
side wall, seemingly by internal force, literally puncturing the
cell. If, by chance, any entirely escape from the epidermis into
the surrounding water so that all tension is removed, they im- mediately curl, sometimes tying a knot, and then spin around as they are Swept away by the cilia-made currents of water. Even under slight disturbance in the body, they lose their straight posi- tion and appear more or less warped. Altogether the epithelium with its cilia and rhabdites is a very characteristic part ofthe body structure. Muscular Sygtem
The muscular structure forms not a layer but a finely ramifying system of most delicate fibers radiating in all direct- ions thru the body mass. The fibers extend from one part to an- other, intertwining and interlacing into a regular tangle Which is complete enough in itself, if the rest of the body mass were taken away to preserve almost a perfect outline of the body organs. One has only to watch the constent moversent of many portions of the animal ka make-up to realize the existence of very many contreacte ile fibers. Since the worm is very sensitive in every part of its structure, every part must be capable of quick response. Since the habitat makes it Cacti to find a way thru any jungle of
water weed or debris, each individual must find it possible to
wriggle thru any maze within which food and shelter lie.
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The anterior end is, of course, the most sensitive
region and, as a consequence, its musculature is well-developed,
connecting the several head lobes with each other and with parts
The muscle strands are extremely delicate, slender
farther back.
A very few
threads, most of them ventral to the brain ganglia.
extend directly across from side to side, a few others are ob-
lique, but by far the most run from the different parts of the head
back to the intestine or the integument of posterior parts. They
might be described as clusters of fibers starting froms ome point
in the main body region and spreading out fan-like for t heir in-
sertion somewhere on the inner surface of the head integument.
Since the head is very flat and there are few dorso-ventral strands,
the whole complex forms a plate-like layer, very thin in front and
pecoming thicker toward the neck region.
The muscles of the posterior half for the most part
run between the intestinal wall and the integument, anchoring and
making both more firm. These are all rather short. Other strands
run lengthwise or obliquely from one part of the outer wall to
another, or, from a posterior region of the intestine to more an-
terior patts of the integument. There are also a few fibers reach=
ing from dorsal to ventral points. Taken altogether, these groups
of strands form a peripheral layer just beneath the skin.
On the ventral side of the worm, most of the muscle cells
are connected in some way with the pharynx or mouth, and function
as an apparatus for drawing in or protruding the surface. The
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48 musculature of the pharynx itself is quite complex. There are
comparatively heavy bands of fibers encircling both outer and inner edges of the rosette, while between the heavy petal-like cells very numerous more narrow strands diagonal back and forth. The circular bands act as sphincters and by the force of their con- traction cause the pharynx to work as a rubber bulb exerting pow- er sufficient to dislodge very solid particles of food material. Connected with the reproductive system is a series of muscle cells, having to do with the control of the atrial pore and the discharge of sperm and egg cells. The atrial pore, situated at the tip of a larger or smaller papilla, is closed by the con~ traction of fibers lying near the ventral body surface. These are attached to the skin at one end and to the pharynx or neighboring
structures at the other. In the walls of the reproductive organs
themselves are flat, thin layers of delicate muscle made up of
many cells lying parallel to one another and acting together as a whole. “These may be said to be temporary, as they develop very rapidly at the same time with the sexual organs, and are quite thoroughly weakened by the end of the reproductive season.
‘Thus the muscular system has to do with the function- ing of the several organs or with the specialized reactions of the aifferent parts, acting separately and independently of each other. In this species, it reaches a greater degree of contractility than
is generally the case in other forms.
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Parenchyma Parenchyma, or Mesenchyma, as it is sometimes called, is the term used to designate the tissue,or rather mass of cells, which fills the interstices between the several organs. It forms, as it were, the packing for the important parts which are thus puried and cushioned, fairly secure against at least minor injuries.
The cells which compose the parenchyma are irregular
and variable in appearance. Soft and extremely pliable, spherical
when free, very angular when confined, they depend entirely upon surrounding conditions for shape. Since they are not limited to any part of the body space, but accommodate themselves equally well to the large open portions of head and neck region or crowd into the infinitesimal cavities between intestinal cells, it is imper- ative that they be capahle of very readily assuming any form. Covr- related with such possibilities for variation is a very delicate and membranous cell wall. The nucleus is large tho so clear as to be impossible to distinguish from the protoplasm around it except in cells which have escaped into the surrounding water. The cyto- plasm is thin, almost watery looking, and contains a few rather conspicuous granules, the whole structwre being very simple.
oo. * In functioning, this type of cell serves several pur= | poses. It takes the place of a circulatory system acting as the | conductor for transfer of food materials. As it is in more or | less direct contact with all the groups of cells in the whole struct-
j ure, it forms a basis of connection between the digestive tract
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: 50 and other regions. Where more highly specialized cells would pre-
clude the possibility of such condition, these seem to be able to carry it on thru even a comparatively Jong series.
Another point of importance is the support which is | given to the several body parts, the parenchyma acting in lieu of |} a skeletal system. Since there is not even a cuticle to give stiffness to the integument, and since none of the organs possesses
the necessary rigidity in themselves, the shape is maintained by
internal pressure. The animal is, so to speak, inflated so that it can hold its form, much as plant cells are made still and resist- } ant by their turgidity. Then, too, the soft tissues are held in
place and prevented from crowding one another so that their rela-
tive positions remain intact.
As well as serving for purposes of support, this most
primitive of all the tissues also protects. It is very spongy, being capable of undergoing a great amount of compression, as for
example when the animal squeezes thru an extremely small opening
or when it bends or twists so that some one portion of the body is subjected to especial strain. The great amount of elasticity is also noticeable and causes the shape to vary. Thus, when the in» testine is large and its wall thick, or when, during the period of sexual maturity, the reproductive organs occupy a great amount of
space, the parenchyma is so compressed as to seem almost lacking.
| On the other hand, when the digestive cavity is empty and shrunken
the whole pody mass will appear to be composed<< of parenchyma,
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51 the cells of other sorts being insignificant in comparison. In the
case of injury, also, this valuable layer plays the main part. Forming scar tissue and furnishing cells for regenerative purposes, it seems embryonic in its ability to develop inv arious directions. It seems not far from correct to sum up the foregoing characters by compar ing the parenchyma with the embryonic tissue of other
forms. Digestive System
The digestive system is more complex than that found
in most of the other groups of this class. Itconsists of a very
well-defined pharynx opening into a rather simply shaped, sac-like
intestinal cavity, which occupies the greater part of the body space. So conspicuous is the whole structure that the general appearance of the animal depends entirely upon physiological con- dition. While all the other tissues are transparent and clear, the alimentary Pei oelaions shows heavy and dark, giving the only suggestion of solidity and without which the individuals would seem al together e phemeral >
_-—s« Situated in the mid@le of the body on the ventral side, is the pharynx, which, viewed from above, is a large, sharply marked rosette. It is in reality an inverted cone or funnel with the small round mouth at the tip, opening down. The rosette is | never entirely flattened, but slopes upward and outward to its connection with the intestinal wall, This connection is made with
the very outermost edge of the pharynx, just above the large cir-
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cular muscle band already mentioned. The lower,mouth-end of the cone is held in place by its attachment with the epidermis and by means of various muscle strands which also anchor it to portions of the ventral surface. There is no sharp line of demarkation between the external epidermis and the epithelium lining the roset ¢ 80 that the mouth is bounded only by the circular sphincter muscle, The pharynx wall, itself, is thick and heavy, due mainly to the size of the petal-like cells which, together with t he muscles which control them, give the characteristic shape. There are from seven to ten of these wedge-shaped structures arranged with the smaller end pointing down toward the mouth. They are very rigid and act as a series of jaws. Criss-crossed between them and running in several directions are numerous strands of muscle fibers, which
function in such a way as to vary the position of the rosette cells
with respect to one another, and to make them of value in seizing
particles of food and in controlling the food after it has been taken into the mouth. Ins tructure and general mode of action, this resembles the bulbous pharynx of the Prorhyncidae, where the rosette cells number only four. The general shape of the whole rosette is changed very quickly and the complexity of its action makes possible a wide range of feeding habits.
The intestine into which the pharynx broadly opens is comparatively thin-walled. This pounding wall which is very trans-
parent and elastic is made up of one or two layers ofc ells which
act as an absorptive surface, and are subject to an enormous
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53 amount of variation in size. When there is little food material
either in the main portion of the intestine or in some part of it, the wall draws in, so that the cavity is entirely obliterated. This is prought about by the pressure of the surrounding paren-= chyma as well as by the compressibility of the lining cells. On the other hand, when there is need for greater amount of space in the alimentary tract, the wall is crowded out in all directions, portions of it compressing the muscle strands and other organs. The anterior end often reaches as far forward as the very tip of the head, pushing its way dorsal to the brain ganglion, andthe eyes.
| The digestive processes are carried on by means of these simple cells in the lining wall. In some manner, the food material is reduced to very minute clear globules which are often ejected as the result of Slight pressure or otherstimulus. These globu- les are absorbed, converted during the process into an oil, and stored as droplets in the outer layers of the intestinal wall. These a@roplets are extremely variable in size and color. Those found in an individual at any one time will range from many which are just visible to some one-third as large as the pharynx rosette. The color is always very clear, a prillient yellow-pink or some shade much darker. Generally, all the globules ina single g 6ci- men are of the same tint but there is the greatest difference among several individuals taken from the same very small aquarium jar.
‘These rather striking Getails in thes tructure of the
| digestive system are characteristic of this family and sharply mark
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it off from all others. Nervous System The nervous system contains fewer cells and a smaller
bulk of protoplasm than any other part of the whole structure.
The several tissues and organs are so arrangéd that they are very easily reached by means of a rather scant supply of nerve material. . The kinds of stimuli received are few, as 4 consequence the recept-
ive apparatus is not at all complex and the problems of correlation
and response ares olved without great difficulty. Apather high
degree of sensitiveness in certain directions and the possibility
of a precise response seem to have been achieved with a minimum
of anatomical detail. As a result of such primitive plan, the
nerve mass is not sharply marked off into separate divisions but appears as a very homogeneous, almost undifferentiated whole.
The main or central part of the nerve tissue is the brain ganglion which is situated near the anterior tip of the head, on a line with the widest place. It thus 1ies near the middle of the head, between the main muscle strands andthe eyes. There is a slight division into lobes which gives the appearance, at least, of a double structure, but as there is no suggestion of symmetrically arranged nerve branches or in fact any regularity of position or size of fiver, there is little to show a truly paired condition. The nerve cells are fairly large, but show little detail of develop-
ment. The ganglion contains, also, other cells, either for nou-
rishment or support. These may be distinguished by the fact that
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‘they have no branches at all. It may, of course, be true that they later develop as true nerve cells. Thee nerve connections can hardly pe said to be definite trunks or even special nerves. Since they seem almost like projections of the ganglion, amoeboid in their promiscuous wandering. Most of the fibers, or nerves, a6 they may be called provisionally, find their way to the skin, spreading out over the inner surface and forming a layer of receptive material Thus, these celluler projections are short, in the anterior region spreading out like many irregular rays from the ganglion, and be~ come longer and longer as they reach farther and farther toward the posterior tip of the body. Therearevery few nerve strands ex- tending toward the intestine and even the muscular system is poorly supplied. | The greater part of the nerve mass is evidently sen- gory, and it seems the function of the motor nerves must be pro- vidaea in some other way, perhaps by the direct responsiveness of
the muscular tissue itself. Since there seemto be no cells purely
associative in their activity, the various stimuli are probably
passed from cell to cell. This fact would account for the relative small nwaber of cell pranches in the ganglion. But however pri- mitive the nerve tissue may appear, it very truly shows a great ad- vance over that founda in related genera.
“Closely connected with the nervous system and acting almost as a part of it, ane three types of special sense organs, namely, the skin, the few specialized tactile or taste cell groups,
and the eyes. The skin seems highly receptive thruout its entire
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56 surface and is evidently the most important medium of communication
with surrounding conditions. Only one cell in thickness, it serves
as a most efficient conductor of stimuli of probably all general
winds. That it is extremely sensitive is apparent from the great
number of contractions constantly taking place. On the ventral surface of the head, there are several special groups or patches
of more highly differentiated epidermal cells. These patchesa re each suppliea with a special nerve branch and seem to be of value in selecting food, and in ascertaining more exact details as to environment 30 that they may be primitive taste or rather olfactory organs. They are composed of a cluster of several cells with rather heavy, rigid walls and denser cytoplasm. The whole head is generally in rather c onstant motion, parts are protruded or pushed around in all directions as tho investigating and locating any nearby source of food. It is with these sensory patches that such activity is carried on.
: The most conspicuous development in the way of sense organ is the eye. This is hardly more than a light-detecting organ put is noteworthy pecause of its characteristic shape andcolor. The eyes lie one on each side of the middle line just darsal to
the prain ganglion beneath the epidermis. The carmine-red color of the pigmented portion makes them stand out sharply against the cle head region. This color varies somewhat in different individuals
put for the most part is heavy, dark, and very opaque. The outside
surface of this dark part is exceedingly rough, covered with
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coarsely granular knobs. The shape, too, is irregular, very jagged, almost spiny, and often with flecks of pigment completely isolated from the rest. The position of the pigmented portion is quite constant. The pointed edge, which narrows outto a sharp, bent tip, always is placed toward the middle line, at right angles with it, ana directly opposite the eye of the other side. The remainder of the pigment is arranged like a cone-shaped cap with the much sere- rated external edge clasping a very transparent lens-like cell. This lens is all but invisible so that the inner surface of the dark cap can be distinctly seen much lighter than the outside, and also much smoother. The crystalline part is a solid bean-like structure, not ever exactly alike in the two eyes, and varying enormously in both size and shape. The nerve supply comes directly from the ganglion on whose surface the eye rests. It can hardly be said that optic nerves exist, since there are only clusters of cells which send branches or divisions of protoplasm up into the pigmented layer. It seems hardly possiblt that such an irregularly
shaped mass could be capable of being more than a light-detecting
1 organ, but the nerve supply would seem to indicate some true see-
ing ability. The Excretory System
The excretory tubules are of the typical primitive type. They are protonephridia, rather large and well-developed, but ex=
| ceedingly thin-walled and delicate, so that they are invisible ex-
cept under very favorable conditions. The two long tubules have
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their beginnings somewhere posterior to the middle part of the
body and the extent and size are variable, so that in some indi- viduals the tip may be very near the tail. The tubule, not at all constant in its position, wanders forward thru the parenchyma, quite deep pelow the surface, until it) reaches the neck-region, where it bends dor sally around the anterior end ofthe intestine. In the head, it lies only a little way beneath the skin, being dor- gal to the nerve and muscular systems. A little in front of the eyes and petween them, the two tubules, one for each side, approach each other and then pend around ventrally, forming two loops. They then run back still in a ventral direction till they reach the edge of the pharyngeal rosette, where they empty. Thruout their whole length, these tiny canals are nevert aut, but are irregularly looped and folded so as to allow for a Large amount of stretching without any strain to the delicate walls. The flame cells are difficult to find, owing to their diminutive size and the deeply
embedded position of the tubule. In some instances, there are a
number of these waving cells scattered thruoutt he length of the
tubule, while often only one or t wo can be found. As a whole, ther¢ is so little variation from the common type that a general de- scription will apply directly to most details ofthis form. , Revroductive System Only during a rather limited period in the yearare the
reproductive organs to be found. Then they stand out definite and
heavy, easily recognizable among the other more transparent organs.
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‘he season of sexual maturity extends from about t hefirst of Nove-
‘ember till the last of December, and during this time a single in-
| dividual will produce several egys. The animals are hermaphroditic | pat do not possess $0 complicated a series of organs as is generally | to pe found in this class. In brief, the reproductive organs con- | sist of a paired testes, a Single ovary, with small vitelline glands and an atrium seminalis which opens to the exterior by a short canal and pore situated on the ventral surface. The organs lie close together just posterior to the pharynx rosette, ventral to the intestine but to a greater or less degree displacing it. The group of parts thus formed makes a noticeably clearer region, oval } in shape, much larger than the pharynx in extent and lying in the | middle of the body. The two testes are situated on the right and left of this transparent part, with the ovary between them and in all three instances the ducts open forward andventrally into the | atrium. The vitelline glands, having their connection with the ov-
| arian duct, ramify for a short distance among the adjacent lobes
| rather large duct leading to the atrium. This duct is very broad at
the point where it leaves the testis and narrows gradually toward
| the opening, which gives it a funnel- shaped appearance. The wall of
¥ ¥ ~ 2 a aie ————
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* fo rhonmkbhe ods somes sormiekd fate a tez (tiswt - ®
toictw eee ane "Py i (oO LOWS ort? er ai ‘a
° a
i gouge ti i f 2 yee) Ay a be Sew: | a o> Sarto edd ote Tis bem DSLR osGelp ore 8 ov formed’ Sangre
ho iw Saovetg 6 Gin ae ce02 ort 30RN, Kesoneg
ie
) 2h bees weed that o2dt) suelwd 2 oe ost garneot ¢ ‘ie | Eesti eed ep Taito riortenes baa else? edd Newnod ahi sorte
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nme gat esau dit balers haan
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to 6ach other. The wall is, however, of sufficient transparency to reveal the mass of sperm cells lying within. Thruout the whole reproductive period, the testes were tightly packed with spern, all seemingly mature at least in size. The ovary varies a good deal in size at different times during the sexual period. It is made up of a mass of extremely large cells packed closely one above the other, crowded into narrow plates, from six to ten completely filling this organ. fhe shape is that of a pear put varies slight- ly toward an ovoidal. As the eggs become mature,at the Lower end, they round out and draw away from the mass little by little until they escape into the duct leading to the atrium. Fertilization probably takes place while the egg is still in the canal,which is very short, or at the time it reaches the atrium. The immature eggs are thin-walled with very large nuclei and finely granular pro= toplasm. By the time the last egg has become mature, the ovary is very much diminished in size and is ready to almost disappear. In the atrium, which by means of its heavy wall becomes the egg-caps- ule, the ovum goes thru the maturation stages, develops the yolx- i] cells, ana gains the heavy wall so characteristic. The atrium lies on the median line and as the egg enlarges it becomes more and more | conspicuous. By the time the ovum isr eady for laying, it has a
1 size nearly equal to that of the pharynx and has stretched the
| atrial wall to the limit so that the pressure is great and only a
‘| small amount of displacement will cause it to be extruded. The
| cm al Leading from the atrium to the external pore is short and
0 ay PRR RR HIS j Oru y8 teed hated LU babe ni <8 . hn et
ine ’ 7) j
hiod w ods 2aeeei erilatd sv. intel a Lie ores Yo epee agers oo lw Seopoke ‘witness sae segaes ont downs
.
oon 8 Shay vearo et vaste ‘a seaet 4 ta ine way
37 «64bOtsey Eoexan ag anita aout } soon ke
ig 2
ro \fetyo Bestia side epiel _Tsaredne te iqnon red ot ate imvmi (apiedy Werten ond
~
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fe faree wiv ad itive @l nae ait elinw easld |
ob ti mk esT .nceind a ode aodose 3 31. emis of) ga 1 4 ;
es 4 + Luger sfondi time ietoug entel YIev “ate be i Low “tthe Si \u7®@ ert ,o%usa sneosd ean one fuel ert wens ont 1 .tonqune kh Seon of Ase ei ud pple tl hore ted
at cbn-pas oravesenoed Ilaw yweoed eh to NOM ud donaw 5 =u Low, on? ayodeved PORSIe MO see vince oft weet) eeey & acll mite sd? soi dveiaatoaisds 08 IE Laset erneit ey. 81 bro eae SRRROE. eee BP Ee Bae exit as ‘tins oak sm
| aot oA gee 40% view “el ve, be out t “eats xe
ame «
ue boduderige eed Lia ome 429 haiiey ots: $i st of ee: r “fro ‘seer ena ar euteon ed? tard? hal thobL buad ot
ete Ges
lees pe
at »Aahsrsaae oe oa aa OGrIRe dite amommon Le
a = ers bre étectl nes, Shenae ots ot
Meets thy ig een
eld firmly in place by the surrounding tissues, but possesses a most elastic wall so that very quickly,when the pressure is suffi- cient, it enlarges many times to allow the passage of the egg. The pore itself has a very flexible wall, the epidermal cells flatten- “ing gna lengthening to an almost unbelievable degree. At t he close of the sexual period, the organs arev ery much depleted and have
shrunken, losing also the definiteness and toughne 8s of t he walls,
. go that the whole appearance is very different from that of the
earlier period.
Be rs ' i ror e or
LeRieneoy Joe) ReMae Ls + Annee 8 -libue ab Sigeaony on ote Si mE et wi? «ape lene Be eR, BHT onite We BARE Coe stetinl?. affes femnagitge See pe ita ee a
egolo od 2 ak 08308 eieioys toate serelie my overt Nite Sate foes toeim Vee Vv. oeR: esug¥o tt
oilow of 26 Sethyees tas etenmtinited ont cote
> &
“i? Wo eds A) grovsttln yasvi ak Cha et tis) &
a, ¢ A ‘ ) - aa i no ome _ ' iy hale " - { : - { “e a . - at $4 od _ s i) al i * - A a *~) j rae . ca. ae - % = oo a Tah oye) { ie § oa) San - 7 ne -_ 4 f + ide 7 ¢ ‘is * asl STS AS PAOLA ee =o
rr, Ot ~~ ea Ee away 27°)",
DEVELOPMENT, Strongylostomum rosacea
Individuals carrying eges were first noticed about the
' middle of November, and a few were found in every haul made during the next four weeks. One more appeared on the twelfth of January, | but none later In all cases, these individuals were not as general- ly opaque as those not sexually mature, i.e., the intestine was not so clogged with food, and oil globules were present in only small numbers. The body was also much more slender, indicating either that the regular amount of food had not been taken or else that the strength was being used for the nourishment of the egg. Altho sen- sitive, they moved around Less actively than the others and seemed to be almost lacking in vigor.
The exc, which develops singly, is carried in the atri- um seminalis and is visible pecause of its opaqueness even to the naked eye. It appears as a thick whitish spot, a tiny spherical «nod causing the surface of the body to bulge a little on both dor- sal and ventral surfaces. Under low magnification, it shows as a red-brown sphere, surrounded by a capsule made by the wall of the atrium. A little smaller than the pharynx rosette, this capsule generally lies just posterior to it and near the middle line of the pody. On account of the transparency of the body and the heavi- : ness of the egg, it appears as conspicuous as the rosette itself.
The egg capsule though retaining its relative position in the body
parenchyma is very movable, recalling a balloon buffeted a bout in
ar
_ * 4
‘tieaes ésdenow ent ‘te Buowoigence tn ero9cgn tt, ebos ents wk ‘mold Leag avadnson eet eee
3 he s ni 2H0d & ha litae Aipstssvtin crates a et = a 7 - ~ soma pee
4
sub tiene Dise yrs nk haudd ow WoL = nus, Steonat “be ASRMaee edd xo ‘soo i
ey ob SOR OMe elarbiy) te weeds Seda ae
rete 6) OMS | mae maccraa anit inedts ne 1 Lome ety th io omit Sihein rid won ein +8 oo Aojreaveg. som
Juote. heskoek dont evew gone akbepeal ‘
Wigoeta ont. ..0./ .udem yifeuxeu son | ie
-
® tivo feb FAmeeng erov selotoly Sto bap IM
sab
TES SESS tauiha: , iene ie som monn os is ase | nm? gife APRS! nead don bet boot To SeirGanes COITA jae ont 20 3 reiente Snone or? 20% ‘amas a2 668 etate ea cori 4 vievitoe aval Brows atonly nt gnbionl
ti Bt BRMEO et viata agqeleveh doidw .pa8 Sime
Ove GQatitipege ost ke onosced eiglaiv el Ans’
orhge unit Se ,voge feiiign orate * ae eaRegge | =
ot no SOYGEL a@ ogicd 02 vhod eft Bo coping an ewes ae MBSGodLinyem wok sahed head aue! “a
to Dw ert ec hen aati asl xa pohasiosare :
ets nak vies ab Re Yorwsepinans oat 3 tmneaee
63 all directions but anchored to one spot by its tether, which latter
is comparable to the short canal Leading from the atrium down to
the pore on the ventral side of the body. This pore is generally
almost invisible, but, under some conditions, it is draw up into
P'S rather large papilla, just posterior to the pmrynx. This draw-
ing up is due to the contraction of muscles in its walls and in the
survounding integument.
As soon as they were discovered, animals carrying eggs
were isolated in small watch glasses, where they were kept in
about five cc. of water taken from the aquarium jar in which they
were found. These jars had been filled with water containing a
greater or less amount of algae, water plants, many crustaceans,
other rhabdocoels and an inch or more of mud and sticks at the bot-
tom, in every way very much like the natural pond except in temper-
ature, which was slightly variable--the room temperature. The
temperature was, of course, very different from that of the water
under the ice in the ponds, but seemed to have little effect on the
development other than perhaps to hasten it. This appeared true
from the fact that in the hauls made every few days young indivi-
duals were constantly found in increasing numbers and of severai
Sizes up, from those smallest and evidently just hatched. When
isolated, the individuals soon came to rest and easily accommo-
dated themselves to the new surroundings. Since the watch glasses
were 60 small, there was some change due to evaporation, but this
Was as slight as possible because they were constantly watched ana
¥ .-@ wesinl doire (feodved tf Veh doas “eno os. botortuna:’
ct woh. mpydad @ erte wee 2. gestion ieee de oa
a f iaraqey a SNOQ ain? abot - ats te ebie. Ofnl qu awh af th ,amolyiniace | a a:
rwesh alg? sttitaty ot of Yorwsdeg Jeng
= a Jae
anne priiyren etanine ,Sexovouals aise.vong 66 1068. 7
“i 2008 e%ew YOTs wrecde -ecensls, fone i fpore sak
weds sto itiwoek wat nese el meu? ola vocew Ié f
h Siaielnes ORK Silie Helis} 6g ‘bed ans, sed?
¢2 AOSLIGMID yan .ecnal¢ wecew eaple to FAUOI |
“soc ais 3¢ atoite One fam 20 eicom Fo Mont) ms bem ate
=—Soamss gt Jqeone fnog Lowder ort oni f Om Sieg Rw,
will .@utenegnes moot aty~-elaaiuel _liiptie sew :
néjuw oef2 To teddy wok Snore TAL yey soe 100 Do sleet .
ent. and toe¥te @Le3) 1 ovat 03 Beswet tod ebseq ef? ‘nZ
ood Seewagye ead? It nocand oF aqgeeky auarty “onto:
-by int govey aye wen Yteve oben meena Offs ai Jada dog
Loxevee To Arar ‘siedimert -paabeiowinal ad Hest xitunteroo
ceeW .detoded sense ¥Famebvo brs see Lieae seots i
= Aero \iaee ews sae ot anst Looe, cepa eats
Suverty rosee ae auike egnbdavorias wen ony of | éifs Jud ots evouere od -pmb eyeusets eee Po
thee Sroriodanw iceman eal xena suncog tsa anh oo ged ae 4 CPR IORI om 2 Hs re ‘@s) - _ ae: > 7 pe Sey a ee : Soir ay) ioe ars
Vv
ee eetie *
64
the water replenished or completely changed. In ordert o prevent
too much evaporation, they were kept covered with beakers. Part
of the time the water was changed every three or four hours, and
part of the time once in forty-eight hours. The water used to re=
plenish was either clear, from the reservoir which supplied all the
ponds or else taken from the same aquarium as the individuals thenm-
selves and then carefully freed from all crustaceans and other
small forms. —
At first, the eggs were rolled around and moved by the
force of the water from the pipette. They then either floated for
a little time or slowly sank to the bottom. Two finally settled
to the bottom and became fixed by a secretion of cement, s0 that
their position remained absolutely unchanged thruout their incubda-
tion period. Others were rolled around more or less at aifferent
times. The parents were removed from the watch glasses just as
soon as the egg was laid in order to prevent contamination of the
water. Altho the individuals were isolated at different times
during the day, in all cases the eggs were laid sometime late in
the afternoon, the earliest at 2:30, the others about 5:00. It
appeared that when the eggs was ready or nearly ready for laying, it
required only a slight disturbance of any sort to bring this
about. For example, in the case of egg number four, which was laid
at 2:30 P.M., as the stream of fresh water entered the watch glass
from the pipette, the animal somewhat aroused, contracted only
Slightly, but moved rather quickly about the dish for a moment, and
oven, o 1 SeB4oong +. iegvertc er |
<2 Yipee ae Bere tGe% asaw Qos nota
Ban oot WWE) Ta bart vreye hope ew: toda se. ot hogar iene oT 9 eener a ti aene |
ile Dec ioque doidw tfoyeesen eas mbt mado 5 i
pea’: « Loupiebhal art te sc ems ort users nos
wtto fra anmgiesveuw Ife mow past eStore
' < « Ld,
bot fee Feats betifeou ettew ange ats feu ae
“ot tuieell Wernele Ged? .Wotl .esteqgicg: oriy erst “1950 Seitvaa vigentli-owt. ,vgsio! sdy e3 acme viwele 1¢ ati o€ (Sieg Fo Bode meds oy fect angsed . tah ae apgcoad- bot) (aan? Aesywuittons «Soteloece husloam® ‘2% 22 Spebigo® een show Solics ecw avedtIo
3, ; t = = ie fteot eobendy totew ons eck Ao vores eer Bea
: vw ae
eld “oe nod J aethmeaioe sndwetig. of “080 it. bed e208 be canis @npis¥hib de Besaicei eton ‘eihanvinn! ary uiel oultonms bia Stew BeQo ony GoBRO bie mt ea 37 ,O076 toda exedto eds ,OS:4 28 ceghinas erty, | ef abel t0} vthiip —itieali q0-ebesn, abn yae arta sorted | eidt-getet og ven une te conadntedh tips le & Y: fm '
bini sen Ajiee ee noite BBs "YO! BRAD. one et hinuecne 6 peels, toneeeedile Jee Sine SSW AeA te maucae out oe i ; Linc begombros goewote cartwemee Lema tity: apo te |
herd... Lavompetiss big ee ib wed anes uidoiap. oes arene rior asoue a me AE sire e ee
just that small amo@nt of extra contraction was enough to cause the ess to be extruded. In all the other cases where the egg was laid several hours later in the day, the parent was quiet, more
or less drawn up, clinging to the side of the glass or resting on
The eggs vary slightly in shape, size, and color, show- ing perhaps the individual character of the mother. Never quite spherical, they can hardly be said to be ovoidal, the measurements
| averaging 14.5 by 14 micra. The outline of the egg i8 thus a very Seund-ovoidal. Sometimes, however, one end is more pointed than the other, giving almost an ellipsoidal appearance. That the shape is far from perfect was evident when the egg was rolled over and there came into view variations in the outline ana in the amount of pulging in the different parts of the surface. The color is a | rather clear deep yellow, verging a little on the red and brown, | ana is lodged entirely in the shell. This was demonstrated when - the egg was broken and the white yolk was lost or when the embryo
‘| escaped after hatching, leaving the empty yellow shell. To the
‘| naked eye, the egs was a reddish-browm speck just barely visible, and
| appearing quite dark. Under some magnification, and with reflected
| light, the yellow was much stronger altho the influence of the
| white intensive portion of the egg was more noticeable. The shell “though rather thick and heavy is quite transparent and clearly “shows the yolk granules in the younger stages and the details of
, embryonic structure in the later,
a
Sesinn os “iiwong SAN HOT TOENI AGO ae F son ops on 2 enedw eau Sodio. ot te ai | 7:
yom ,t6 ap ae THOS pits a neha wid) abet sa ao yrvert im s8ala ord) Qe ohie ene of) rion Deis ie Ae ee aoivp weer ssa c tO “esos Sao runsvantm
Rinsrenescem ers hiova o¢ ; Hd oY art pinto?
Sol ,wlOo bas
Nisy @ aud? © wy & enili ute tel >. ee oi; —
| a
i q
“ort? Desriead eons Dy Sito \“quraper aome: te?
eiete orld dal ,Oterpaces, Ja bsioges (se oA dean ze
~—g
fun evo Hel ie *.204 aft? aya, JRBbSVS baw Rear Se sonoae wad sii. ir iitone. oft sh Soot Letay eere ° ; a).
a ; yoLé 4 ort? 46 9 ile baz Cc je"latl insi47iG
ree yr lpaIey ROLE
—
recAd free treo giri2? | noite har museca een-eiat sfonde ote sh, yanks ae, eo cietahiat od? neriw ca. Jno! aaa NH LOY adacw ets baw ae ett. & s Liorte wolipny Sie are? rity” gueittodaet Ax: ofa wes ylenadg teol ao0eue vend “267 ath 0 ioetiow aekw Aree. 0 eae enon ‘nent ott De edt Peed. art vit Le nepnorag oe te anf Lote oft eo demeareon eon asm ise enti, teva cinedé Hrs Sores erst 89 Lhe ris . "o efiegeh wet fom Sep_uts MeRPIRN ort gi
* 2
66 Fig./% shows the egg as it appears during the first few
hours before segnentation has begun. The yolx granules give a cel-
lular appearance and near the center can be seen the nucleus, rather
large and with a heavy wall, The granules vary in size, some being ‘not more than one-quarter as large as others. They are Slightly ‘milky, somewhat transparent, almost a pure white, irregular in
] snare, somewhat angular, due partly to pressure, and closely packed, F en the egg is proken, the granules escape into the water ina mass, the individual ones adhering quiteclosely, and holding their
_ | shape even when separated. Very little change coulda be noticed
q during the first six hours, but soon after that the even appear= Jance was lost, as at different points there seemedto be a breaking
~ drawing apart of the granules, showing lighter streaks. During
me
jthe first twelve hours, the first and second cleavage stages were
-Jonty at the edge where a notch marked the rounding of the cells.
| oa By the end of the first thirty-six hour period, the cell SAivisions were much more distinct, the cells had attained a spher-~ ical shape and had arranged thenselves definitely. The imacro-
neres could be distinguishea drawn to one side of the egg while the four micromeres appeared toward the center and opposite side. At Bererent times, the nuclei of all the cells were visible as small, ined shadows. The spaces left by the formation and shaping of the
sells was become more transparent so that the outlines were distinct
and the whole aspect of the egg was changed, i.¢., the cells were
wel sexi? of? gataah aapegqge Jf 82 ee
Tao. ouag estan aio wil aged wee, Wiles Ae fous ony meee bad mth et Oe ott soon he aniad soe, ate ah yiev eit cicietts, ent haw es ,; bas
Ditgi le oul .qodt eerie ee ael ak us * apingew ,stide. sages fects trate
2
st MBBONG (isKok 9 Bi ,ONwEessg OF Y like ono ¢ ni. “a2se of ofnl oditiee eoloaen, Or ye “bert ywotetort hap ,“fheeolovl np salon, Sep eee
heolton od — earcerio Of ris het | bodsamapiee nsiet =—TroggA eve eat2 = "STR or as esioe ie e3 iniMawes © od © 3 hem OF Ole arose j suo" 8 1G SNEWS “estat i aateote -. SL egy! Sits sounds tqayveols luyoose bg) 3a oie aoneds f fuaeto wrev ueiwoda |! as. urh Fon erray proce ti swileo ofz- Be patbaues ect De: “aid pd Ose a s0Gw ets ,bobtey sped ale yield Jacth aie Se fee ane -elge 6 Reankedtee; hel 6) Lox cris omliteab ebm rast ~yinag aff sy fotinskel a: ovioulindd Seager iat of? elit nt aap ont ae tli na ORO: ;, ries ant verte Lupa | 3A .,0Rka le al ‘nes eo 2 st ae posted plicos se olgieaw pm ahien any Ais, to ee. ort lo pribGivie. Dee HOLA uae edt Ne ya8:
fonliwid saw epmlicgo =“ dure os 2 era ag 3
i vata, ne = ee ee ee sarap = F =F ae ae a } tp ee
67
ering ta+ each other only slightly, but still one integral mass,
very large, about one-sixth the size of the egg and were placed in
‘a hollow plate, while the micromeres, somewhat smaller, lay curved
inside. By turning the egg slightly, different views of the various
During the next few hours, the division stages continued
In many cells, the new walls could still be distinguished but the
| mass soon became so solid and opaque that it was imvossible to fol-
low the cell lineage with any degree of accuracy. The two poles
of the egg were marked by the difference in cells which at the mic-
romere or animal pole increased in numbers,and soon filling= it
- tended more than half way over the ege, giving a typical gastrvla
stage. This wasvery conspicuous and characteristic, as the cells
at the animal pole were dark and heavy, while the free portion at
the opposite end was clear and transparent. During the third and
The changes which take place during the fourth, fifth,
and sixth days are those striking in their effect upon the appear~
ance of the embryo. During the fourth day, the appearance is that
of a mass of cells surrounded by a thick wall. It is at this period
of the various organs differentiate then-
that the xwa anlage
Ay
ihe
P + eee
a
eS State Aoketvib of; evo wet Sen aee Bae
(oe tek mam £ELIS Jee Pee ere, ‘tas os
So das MOA en 6 Brett seed einer, “ertd mk
ty os fo awery FreqeteIh. wiz ty tite nye ott
- al ug : of
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-
Pa
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a
im is » * ~4 ? J 4 5 ; 219 Soleragms. ai> af Eiis 4 bivegs-eiiew wen add:
} Ve F e 3 Mizencntms: saw ji tacky etpsawe hae bifoe 6s Belay Cewt ep) +CUHTHODE To sever Ue aan we e
L fi
ASL27 CPOE ey geet siciis el shogiw seBiiee a7 ‘Te MT? Boge soette oubrts nt gna tane, nee et het . * ie
afer at ctd oh ei ‘2: i4tek Noigt Ba. bodies ee: 36° staves 3 sterdnenten : ae. Leiria edi te .
of} $6 Agtde effer ri —eIsTai mh ate vd Dasa
wty tA. o@eteeoy 3 tek Oe YG {eo “4 28 wow
“yoS.O% ToGo fire .codgar nt hesSetont 6fog
a. . - . se Eee nant elieo seagnoo linea So das dts ae bee
AS, dantqys 8 privy, 28 sf? hve. yew iad Braak - : a
.
"7 @8 woliqi 3O7ORao Dns Sino kes tre a Vitae
CL seg Oe eft ekinw yourvcd . tis ae Otew aa Ie
‘Wilt off pike .teeusqennss han “Ls rely 6 BAY ae
mete of PeNg Geohic enow ni dffoo ie basu eden
>. Bake Fane erty od
i somAtoadgejeds yah daxpen eyes pel A revo 9
er. Pie aes 4
lseneateiccanel
Aral 4 = ie 4 > > - “? © } om eT) F 3
aad
68
elves and instead of a mass of cells the several tissues and organs
begin to be apparent. The first noticeable change is in the wall of the embryo which develops into a clear, very thick layer s0 closely attached to the inner surface of t he shell that it seems
i o be merely e | lining membrane. That this is really the integument or epidermal layer of the young worm becomes evident when, thru
the lengthening and expanding process, this wall is folded in, away from the shell, Both outer and inner boundaries of the epidermis
3 “e sharply definea, so that the latter is a conspicuous portion of the embryo. The extreme thickness of this layer may be explained
a f - = |) by the cramped and contracted position. During this same period,
| the muscular system begins its growth as many strands of cells at- e:
BE ic "tie “Firm inner wall of the integument. Thruout the fol- 4 lowing days, there is an increasingly greater amount of contraction and movement of the whole surface of the enpryo. It is constantly Sie “epasncaicelly drawn in at one point or another fora minute,
| ana then slowly released, as tho the different fibers were each re- ceiving their quota of exercise.
ri: | About this same time, also, the anlagen of the intestine made its appearance as amass of cells nearly in the center of the egs, the connection withthe mouth not taking place until later. It Was merely a plate-like layer of cells at first, without any of the lobular ramifications of t he adult organ. Little by little, out
th u the parenchyma, small strands ofcells became differentiated
nd enlarged as branches of the main portion of the digestive tract.
ex oy aovnet? LDeaevoa) ori eT iso ae soon Caw wit cal “el « Gopaiefo wilted Ba Sy ai sete att om “oted Hol giiy .cels & ovad ‘sable ;
ob.
compa Js Pen? Sindd ae ite estas ae
v : a mmetal ete ylines ci ulin? mact onetime f
oe
i i ¥ iY ceiWw Seodtye ecroned Mitw Erie adit Se.
= -
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we yt BEMESD af iiew 52 osooty ym images nets, SepiGS Oo Po socuehyu “ere Ue ere) fjok
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a
2989 OMG Bil eure rors tto0g Gates GS | a
ate aliso LO .ebnets:a (i ae CIvO% tf smiger ae
4sfet ety ovo? togomgeart gets he Diigo decete ;
woliosts neo 76 ioe Jn La nw2de2a onl. i ez
remo tenbde 22 4 ethytidd ie «eft =e niet. alae ori mm ened ppt estos 8; Log ane. 2 2 GRAD = a ¢og8 O'sOw BAT ct cyte TOTRLD ony ons ea Jwesa te’ eho, to nts irideect a2 SO megeics. add cele ens enue nil : nmi? Yo aaiaee was ak Wives ettas =o ia hae @,3s é] otal. Liga hed, Qaida sd yom (ee ovneliatw “fs To yng Seep Wy Geet ge Alito to ess oo piled ogi Bitte? angio stohe’ wane
bc Je te COT Lh eager a £io-c To wonaksn (sf
Adve dg Bia: hd io a ees on? ean
69 Both anterior and posterior ends began to lengthen so
that the spherical condition was gradually lost and the much folded,
much crowded elongate worm was distinguishable. The two extrenities
were clear and very conspicuously different from the heavy, dark
middle portion. In the anterior end, the mass of cells which forms
the brain ganglion began to take shave and a little later the eyes
ould be seen. The two loops of the excretory tubules as well as
the strands of rhabdites were visible. There was constantly a very
slow rotating of the whole worm in the shell. It took sometimes
from one and one-half to two hours for the whole embryo to turn
| completely over and it was rather difficult to distinguish the dif-
} ferent parts,as the embryo was much twisted. At other times, the
‘movement was much more rapid for a minute or two, and then the em-
| bryo would remain quiet for some time.
By the morning of the seventh day, the work was s lowly
| twisting and turning almost constantly, often making a complete
rotation in a few seconds. About this time, at points where the
Sa
integument was drawn away from the shell, in the space thus left
ong and well-developed cilia could be seen vibrating rapidly in
their close quarters. As soon as the wall returned to its posi-
tion against the shell, the cilia flattened down end were again in-
visible, altho their influence must have been felt as aiding in
the movement of the pody as a whole within the shell. It was to be
seen, however, that the development of the cilia was parallel with
the increase in the rapidity of motion, altho the muscular system
— >
i o1i ry) ir es 8 ‘
RITSO I
af
italy: erm ed cnr Jnete TT By tenes Rapids oe
*
x “a
wert oF Geite® a nod ch wane Ges Gay ae
| ee P ; Le ety
ertindel oF mays. Bime nol aslaeg ro ogee tote att Hat Soe el Deabetey vow noi Boot
pusxe ww est wield Sis tye ee fester atone on
oe
toide fins Te.2sem omy «HHS ‘yo krea tin ie | bs tt “@teL wiiril o bao 3Q@Rade. srdd) oe ay
itor en Bettieus \ wee ait? te suscel ews ott
0 RRR PS, oct Sig i¢in Sam) eel he
at
iyoumn woos 2% .L ' st gion piadiw adv =
“re
ity fa dsseys: P27) + ad ; Lib- wadtgenicow a
- f
Sit weit “aiito FA .. bevel Wt fou ey ve aah
ia)
>
of abeaw aiew aii vel eMra2. aft TO padre Pans eitteicaot @ anlidam cbc to - Viiweteaes stomis :
ay aga ae intod _s a ai too ts - 3 eapeyes: wt
i ibid ptt rancty ‘oan oF Bios ab is: moods
i aulbs oee 266% peed awit. Jerre scengthe
nis many Offs ,0' o oleh tet Siges LO
steek 3 ene ¢ "woe iwrmp
vol andy pera © ch (Clos oe? on ‘ame sae
=
cay B2k O@ Peeters Ik ca ort
loqe. 2tew, Dew seu hare dap 13
ae t Bien 4r effets ous yield de & Loy 4 & eee
siitw tosdieeg saw adie: ad) te ninstoat il a
weleye tolLoge ne Thal baearea gehen & te 4 ae
Nee, ne on
i i also had something to do with this motion. The intestinal tract
was beginning to have a more definite boundary and to extend both
forward and back, and to a slight extent around toward the ventral
side. During the latter part of the seventh day, the eyes began
to be distinguishable as very irregular brownish-red masses. They
were almost crescent-shaped with the center somewhat pointed and
jagged. They lacked, however, the extreme roughness of the adult
form.
By this time, also, the several folds of the integu-
ment were lost and the worm had straightened out, doubled only
once upon itself with one long fold cutting thru the middle of the
egs so that the anterior and posterior ends lay against each other
at one side with the dark mass of the digestive tract sround on the
other side. Thus, the whole ventral surface was turned t oward the
center.
During the eighth day, one side of the egg showed a
| fine, dark line running around a portion about the outer surface
of the egg. This line became more and more distinct and appeared
like a crack in the shell. Its significance was explained later.
The rhabdites at this time were still very small and difficult to
distinguish on account of their transparency, but were fast taking
the shape of the adult condition. They were arranged a few in
each cell put the number for a cell was snaller than in the adult.
The mouth and pharynx rosette were also nearly complete. The two
heavy, perfectly circular muscle strands and the intervening ro-
ie ale ‘
:] F
lank tansy Ot sKolton side Iq wee
‘3 wysan. OF HAN YNshitead ee | cant #8 ey Ww ot? BAEWOY hisIons snmsee siete & oF neal as
S6NS Ode AD Hiusyos eoR meee nossa. a
oT 8» BeOHBAM Be tere cron (= Lage aa sane ne LP |
iinmkey Sadwems lec ee Beirne - 33
J CSTD att" ee 22urroucn 3S IR Ces ae, Bee 4 =tmedm. .et: T+ Lavsyasg ert? .on.e ~omkd airs
Vane, ba Live 22410 DAM 412°: bet mrieyw ortiz fo 40 te sfhiiin 0. att obs tee GLO soe ane eid iMido Moms dauthuaigs vil Soe “ei Yetoog fits Yehiegas > | jee hana wud ovitarwlR. odie®o. ae ote ede), heaswe. + hearers ent We ‘tadibceayy sflocdw ond a bewode two ots to she an. 98h AAg te Gay Boe cost ue aaive os sued . NOL TOG ndinerte itl coreers oad. Pea ea {a bus Pz ek: £4 o°t0n DB Sant Bieect, nat ,1stel hembateces Bry sonnsithag.te aed + eat add ot 1 LOR WRED bre: Lieom_<aewy -fiise 9" emir eine 7s ‘o) Seat suow sud «van onuicpereatad suedttip ere v4 WOl @ Oepne4: caw yor. io abe ain +3 Lactus. dt et sneha A Keone ae hie auch ows eff ode Lego phritioa os ie ey oveenontng
we ~or gutheoy-sertnd bil Pana sias'#, elomue *
7 —- sa i F r : ~~ aie be eS "Ss
sette muscles were complete. The reproductive organs were not de- _ veloped, the atrial pore not broken thru, the papilla showing only ; as the merest suggestion of an elevation. The embryo was, by this time, very often rotating with | in the shell and was almost constantly contracting one portion or another. ‘The intestine now extended well up toward the head and back almost to the end of theb ody, where it was broader and thick- er. In a lateral view, it could be seen extending ventrally to the rosette and the ventral wall. Several rather small oil globules appeared in the wall, giving the characteristic orange color. These, however, were very few in comparison with the number which showed even immediately after birth. The embryo had, by this time, evidently pegun its metabolic processes and was an almost perfect individual.
During the first few hours of the ninth day, the ring in the shell pecame very conspicuous as a point of cleavage and
gradually, bit by bit, the cap-like portion pulled away from the
y rest, lessening the pressure within the shell and causing a cessa-~
| tion in the movement for the time veing. Later, the embryo began
struggling again, the force finally splitting the cap more than half way around and allowing it to spring up so as to permit the | little worm to squeeze out thru the opening, leaving the empty shell intact. The cap fell back almost into place. The newly hatched
worm very closely resembled the adult except in size. It moved
about very slowly at first, then more rapidly, and in a short time
“0h Jor SW ERAQIG HUTsoRONGe st alia pepaiek:
(ioe yotwode abttgag ett tics ieee rom ohog
ee a 3
“Jiw gnatieio® mgt’ viv jon} asa ww ane
“6 nohtuey' ono jabioorridces Adeasenqoo ieomtn a rte BOS wet! Sr iewod us Claw saeirevxe wor tea =Soirty bas sehwo 3) Jt engi She (oda to Dee
of vlissiney ER TRA mth 80 Bie o 9f qwoty ie
ae livfoin {40 [I vottex, etove® .4ilew Javgnrey. ofs
MOLOD es.co'to, DES TAS roams One pee RE ae j
datiw sade nit f7ly NOR a *s IID ek weak wise a :
wemis aint va ond ovriastnd of]. ,fiuig wile ~leiaky
gi onte «8 830 bree @esnene gd at Loctad on asi
1 (oh otete pete te wtived wet teakt ond ante mevesto To trniet A ae ovens Eeqpaneo Yoer onnved
ed: wet Lewe foo L kro tue sg mntisgne arts stowed -hooo © gxletas. ine Liste wrt elntae onneannd ate imied oye! sit NOSE ee pore ocd 0 ae renets Att. = cada ia ytlen!t conch ent
eit Ikateq of ae oF ft sabia ag at “pethwetle. fuse: ilerte usqns on f qauvaeol <aiideabli ent wes 100 sec nectotan yiwen oT oot, oldie: seoute x0 < avon $2) senda mit Sgpore: hata edt |
i o dsorte oR yt Abe Ree a
72 was taking food in the same manner as adults. The color was that
of the adult except that it was very much lighter. The length was 0.75 mm. by 0.60 mm. to 0.86 mn. by 0.65 mm. The animal was
| little more slender than the adult.
LIFE HABITS, Strongylostomum rosaceun
The surroundings and irmediate environment of these
forms are much the same as those for other rhabdocoel species,
Bs. rosaceum lives in ponds containing a rather large amount of ‘| green algae and perhaps some few other water plants with usually a j muddy bottom, more or less deeply covered with leaves, s ticks,
. and organic debris. The other animal forms common in the ponds are
| such as will be found in very many other representative puddles.
|) About twelve species of Cladocera, fifty rotifers, avout a hundred Mprotozoans, ten or twelve aquatic oligochaetes, besides very many
| insect larvae also iababit these ponds.
Several enviromental factors are of some detailed
| significance, perhaps the most vital of which is the water condition. ‘The oxygen content seems to have little direct relation to the
life processes, as the animal carries on its existence with seemingly ‘equal ease in the clearest, freshest water, containing a high per- centage of oxygen or in water heavily laden with carbén dioxide.
Sl end water tho constantly kept in motion by a steady stream
|
| and muddy. Sometimes thoroughly clogged with algal MASSES so that
Yunning thru it, was often, especially near the bottom, very thick
sat? een soles gar: .ed fide ep verre me ‘eet @ ou djgnet ont seedy st oni ce emu tk “yemta saw famine aqt .ser C840 UP oomme 88.0 of
+tiuba off ai ee
ani c on no itund seeiaeemt Bae egedhaere
wl foo Ano erts +ytto wet seott 6s bens mie t. saited o aniaietnoo abaog nt ei me F vis Th ke Wel ' . ta « \ r, Ci: iw Binki¢ iecew tad 0 ve? omos aganers
Seyveol aii Peioveo Yigqosed ea0I t0 8 ou — : : a +: ‘ sme Lae ® aT 43 Ab omemes giSer feuinm “hutto s: » 3, 4 O° aa
.-- (Oud, GVA ReeeiGet Sarto Yin seary si fouot bei | Hodes, ,etehivo: yibit ,2tes0halD To ake sv gobsead. agsoearindgs to steuupe oviews 1 a 7" -tmaq eceds tides oaia t
fligeh omee to oterevetogs Intrenet us sMOLsiiaoh TeTew orgs 2 folic ta. testy 2o0m ode: ouatiog ip of sotsa ter eres Laos l event G2 some a9
Sluntmosa tz iy 81RD wit mo seierno, famine oft We a
— ot ae et
-18y deid «i gotakedaey aten Sqoduort tuarcolo ott
-obtnols mkitao siiw aeRee Yitvacd totaw at 30. sseete: “noose. a “ud mo.ceon ne sea <Liimaenog ont foirt yooy yaetgod od’ aden Sas aah cc
Z
73 many parts were dark, it also supported an extraordinarily large
: population of animal species. Owing to a lack of balance, a number of times, in the aquarium jars, the water became very stale so
that there was a great amount of bacterial growth and much of the algae dies. Such conditions were, of course, fatal to a great deal of the animal life and in time would do away with those of the flatworm type also. These, however, seemed to withstand such ad- verse conditions longer than most of the others. The water temper- ature varies within very wide limits without causing any great difference in life processes except, perhaps, in the case of the reproductive organs. The Suraner temperature is high and when stand- ing in a sunny window, the aquarium jars were often warm. Here the animals thrived, being more activé in the warmer water. On the other hand, the reproductive season comes during the early winter months and that it is in the coldest months that the young genera- tion starts its life independently is probably to be correlated with the low temperature. Thus the vegetative activity seems greate er in warm conditions while the reproductive organs function alone during the winter. However, the Life-cycle seems to be completed
very soon after the eggs are laid, the individuals not existing
thru two seasons. This may be due solely to the depletion of
organic strength or, as seems possible, to the fact that the sever- est and prolonged cola comes at a time when the animals are weak=
ened and unable to withstand such rigorous changes. The r eaction
bom Al «
'oLlomos Od Os) taiese shox-ott! ad ad Rog #
1« VV , a
—
&
mo
to
iin, ate ant tet
yey Bad Gede adtnon teshioo odd at i 32 =
“lye
- ~
wiles me Be fogs ath ye ‘onan a sorting 2b Yost 2 ws perked sates tet View eeided sofee od sa foun fam (tweay. farcosnad I¢ Sri
sa'hs OB OC lasat guns te ote onontiOnge
41 blwow sete o& hans :
ADDONS AGAR Weve
Bintedt LY oy Herod
Arie art? eT f.
VAS BAteuRS JLo
GERS ei it yey
hieofgich at acu:
JIE TEU O o1ew &
Nae Dorie
u
wae MiLySIoe evite.
ith: ainegyte +e + ond oLidw snort |
Ta oe
tslowioo-gf go yiiadex;
ayevy aft sudl ,euwsdetogaed |
JOR ‘bepbiehent at: fted 646 aye wut wie
2 19 =yewod rent
et
iat «au leat oe ,Wobuie:
a
‘coer mpd? tergdto Sa
vif ehiw yore atagg
*. ~~
( , qaske seswotony Et : V7
t
ons 7 *oapue edT .onegte
i Y
iL ovisos Otom gated £
el \iiebbaogebat efit 2525
node ha ams OF YLelen wih ed rea aaah oa
oii “Jay Spt ait ot widiaxog amoon an Hi tee ~inow aa Same ota prety onitt o od sone hee 0
74 to light is positive but neither precise nor immediate. When placed
in watch glasses of water, lighted from one side, the individuals
will always find their way to the lighted part after some time has
elapsed. This was also true in large aquaria, but not as constant,
due to influence of other factors.
The feeding habits seemto be the result of the surround-
ing conditions. Altho active and much of the time living in open
water, thesea nimals do not attack living forms. Live, hard-shelled
Cladocera and rotifers would be difficult for such soft, unarmed
forms to manage, but even the smallest protozoans appear to be
safe from their depredations. Repeatedly, upon encountering a most
defenseless prototoan, the rhabdocoel will glide over it and leave
ee unharmed. However, the whole attitude is changed when the prey
is dead. Very often the dead shells of small crustaceans, some of
them many times the size of the rhabdocoels, are found entirely
covered by an active hungry mass, eagerly devouring every bit of
edible portion. It is quite impossible to dislodge even a single
individual without crushing or injuring it, so tenacious is their
hola. Figure 5 shows en empty shell of a Cyclops being cleaned out
thoroughly by a few individuals. As they worked, it was possible
to see how industrious and intense was the habit and manner of find-
ing every particle of edible material. They remained within the
Shell for more than an hour, constantly at work, until it was com-
‘pletely emptiea of all soft material and ready to fall apart. The
= ‘ ’ en | se
oldiberml sor asioe.g Teil zee
<4
‘pel adt ,pbre o> moth sadtge ere Dee abe NeSEA Imag oetnas L aft Of
ke Jon tnd <aitiedpa oyicl ab oe oele ia
oy Ze dfper i ais ad Olomee «tee: palo aacvld pm yf AS ee” f 198 ont BA "“arut goved.! semen? sais op ws Dor Op atams
Trorm Mey r- g400iTiw a b5inow eaehize
ey. ce
/ id OF Teaqqs andorosc' lems of) meee Sag é {
Te cy i? 4 A res aia BE . oF +btHiOg£d Sahangead
my wroel bis 32 % 200 at iow. lsopekden eff pesos
> , 4
' Pier
; Ski: o oe Dorie 2 Jéiizeae siaitw add , wvawoR,
ae m). ,.eecgawimc {iow io eifeda heed até eee ‘latins brwict s .alccoohdarts 64) toa @ake odes
to sid WVS So ow 38S) L965i0 AGEs Lye avitos®
}
4
i tore os Kove INFOLGIh oF wid iawaou aii ai.a1 at suoiomias os ,l unio tel se ieee .
wie f rine Lo : et ari qo Loy. S it if Tee CoQ Te aewodts é
Sidiesom aaw th oNasery iit? vedi 2A .¢laghiveie wet ag
Sh ee ; SS ANS Hrd "Leite =n iw ‘Sey 19 he ses Hie @iios* ars oideie bortame« ved? .ivs ~— widibe- to asois Peneo eanwitl Sito tee te Vdiretones aH ne ands;
“pet .d bye Lint od Yio, tris Ieitas sey Fton -
75 limals themselves were by that time fully gorged and showed the
ligestive cavity dark and large, obscuring even the pharynx rosette. dstracod Shells seem easy of access and are very often cleaned out
r this same manner. Dear Protozoa, also other soft bits of animal debris, are eagerly attacked and devoured and it is probably in search of such particles which may be caught in the masses of algae . have reached the upper layer of soft bottom mud that the indi- iduals are seen in large numbers finding their way hither and thither in the deeper portions. This may also explain the fact
| that water, dark with masses of organic debris, forms good feeding | grouna, so that instead of being an unendurable condition, it is
one in which there is possible greater vegetative activity. The yo
- | 1
| vole of scavenger is thus played by these small forms and their
‘place in the balance of animal life must be an important one.
Hardly to be considered as enemies of even a single individual, :
| they are merely one of the types without which other more aggressive : species could not exist.
rt seems probable that so unarmed and defenseless a
: creature as this has a number of enemies, but thepe are evidently
| almost a negligible quantity. From an enemy like the fish, which
takes in large amounts of water, the tiny rhabdocoel has no escape
and no method of defense and numbers must thus become the food of
darge forms. Others will stray into the jaws of some enimal along |with the water, e.g., the crayfish, put the smaller crustaceans sean
to make little headway in an attempt to kill and eat these dainty
Sey © WN ee
As
= Te net ce, ? haworta: frie Dew r0m OFIst amry sont, ‘8 AOITSNOT RAKTAY OA neve “rifles oe Ame vee 3
farnels aesia- ywey «or Ans se ASOM te aee'R
i
loniiiw BO etd ttoe sariva otto .aoscgore we ose ak yIsedotq 25 5 fim peer ones aay sileeseil
std no. te Yan aoide aotot. +ffind. art dae | (ete An Oo Troe Ze swans neq 't ! Mita’ rhs : , Pat). eae. 9 Lone eyaet ai } foa® eft aihfgque cale vai eit aenei P1Og sqoos ‘ Bi bos? Doo sé orsc udelh of agieio Io S9e@8 for adler : Dio< (isto inege “ea gaked Lo bassatis oCTaN wet SVS e-SRey Neteety eidsesoy as ons i fiend sdett wl Begely smfy gt & ni ms ot. coum Btls Leutas to pond _ kame! ' gioie & meava te esimens &D heweHte Wridcewm pe oro “otto Node tuedtia Beene old 26 eee te tuo son i p ano lownwtom bas. Oertigny ‘oe tees inet e286, yitnebive. eta s@eds Gite wetioee x6 xeveteeiet 8 sacl ome Hol (tes3) Ont gine erand us mel oe iidaasp oddige. 2 ayfned om gerd Ie jaataien vers? 9Hd , SAW 2o_asanonse { ce ; - to pwork oft omni auch} teum exodtaeia hse santos ot muigie lemine dude To awet sal ori wstitic Aha a70f9 4 mp: wmowmsenun telinne et) sod fie LIAS oad vay" a 0 %
inloh cond #08 pew ULL 0d Sead to, ook eater 2)
76 sels. Ostracods have a habit of attacking a resting individual
and by means of strong appendages tearing a hole in the skin. It
takes a good deal of persistence to accomplish this, however, as
the rhabdocoel will either draw up into a compact ball hard to take hola of or will swim away, scraping off its tormentor in some mass of algae. Many, of course, must meet their death caught in some maze of filament or mass Of loose mud but in open water they seem to be safe and able to swim quickly away from any danger. It may ve, of course, that the taste is not delightful to some forms or the presence of dermal rhabdites may make them unfit for food. In some way, they seem to be able to live a life Singularly free from attack and they mingle in the most courageous manner with many
| “species of larger forms, tho for the most part lurking in some se-
| cludea part of the deeper water and coming out to the light only
Miasionally.
They move very gracefully with but little muscular contraction. The coat of cilia serves as an efficient organ of locomotion and the result is a very even sliding, lacking entirely the twisting and turning so characteristic of other types. In pushing thru small openings or entanglements, there is more or less muscular contraction but otherwise the cilia are able to propel
the body unaided.
In case of slight injury, there must be some amount of
regeneration possible, put there is little evidence of this. Among
lorry tvihal aaivens &: BREKORS FA 1° ded # ©
ee tI) .zidteth aF elet 6 cleo? agitate |
>
. j on a } t
ay \Seveucd eine fact Sere tas
63ad of Day Wied toagmeo. soe ek ies allan va 26
4 so! Tm Swe ae aS, Sita oO galego ‘ete
quod, at 30 opnohive oft ak ovo a0
Sham bon al tosnainc? aac vio giblgwine, ama site! it Ydgowe todd 2Leceliemme See onn968 3 coos Vord Yotdw neco. wl Qa Seoos to aba: aul
am 71, .neguad va oa Vaio lep Bee oz
-
cnet eaos ot Ivifigaieh tom sf @tesy) ems ae
Ey toy iat ceicte Sir qe set iodakt sahealent ake ioe -
on oovt Vinaldneae SHEL & evil of elite ed. 07 neem nom othe ane acdagpives, Jaom et al » lanka ae
22 uaoa of potiayl dad deem of2 wl ods, weet
no tft sd od B60 ghee te tected, 79qReb eit.
—_ 4
fuosum oNetl cop sole ehietenss, yaar evan oO mento t1ricottis de 2m seve siiis to jpeg enh J fetiioe saivoel gabon deve van 6 eb siueen etm
vr savs “Audeo Te clselgetoaisde o8 ansovis Lave “aij od aids me ertin’ om saiwiodso Sas AOL3 o to. - pote (enon, od tas Sued! soto Pays whe
; Rt aga atte otk nae ecing: soten Panto
‘A
TT > healing wounds or regenerating lost parts. This fact is con-
sp: cuous in comparison with other species where scars and wounds
f one sort or another are common. With the above may be correlated hi fact that no asexual pudding has been discovered. It would eas
ar, also, that a form of such complexity does not possess t he
of unlimited regeneration but a condition of entire lack
i ~
eer improbable. Further study will doubtless reveal some pos-
»: ; ity along this line.
>
&Dniow ow pide engdw Se hoon ims
Lo1109. OW Yam Bmore wed are’ » rong, enn foaw tf
ole Ep youn 21 — ond giitObod.
vey
“) 2NO0BOg JO BGOh ww ixelynog Home te Mek ie ‘s vr : ¥ ~
Sal. nulsge te wold.
-roo gator Taeven assole [haw yAhad® seer
—— a / ae = * > i 1 ‘ i 7 « co ys : ra : : Z iz . , & _* a ; P 2) es & 1 - - » . aed ~ { t . i j
' a
Wich Pe ee ae ex ToT ” sere es re | aa = P< dee ees
*; ae
Family PLANARI(DAR
The Planariidae in number of species is more fully represented in the inland states than any other family of the Tur- pellaria. Seven species have been identified, five of which are mew. Of these, Planaria maculata Leidy 1348 is, of course, the most common, occurring in abundance in nearly all rocky streams and in many quiet ponds. Others appear more rarely but over such widely separated areas as to suggest that they exist with much greater frequency, and in larger numbers than is generally supposed.
One of the species with such a wide-spread habitat is that mentioned
| below.
Planaria velata Stringer 1909
This has been taken from two very different localities, one a temporary puddle at Urbana, Illinois, the other a spring at ‘Homer, Minnesota. At the former place, the water was black and muddy with only a minimum amount of algal growth, the specimens coming from the bottom mud, with the loose silt, leaves, and sticks dragged up with a dip net. The conditions in the latter instance were almost the opposite. The spring was of warm water f lowing into the Mississippi and forming a little cove where there were almost summer conditions even during the coldest weather All of these collections were made in February and March. Here a large number of species flourished. The plant forms and Protozoa were
especially luxuriant so that there was an ample supply of food
for a well populated community of microscopic forms. The list
Si
vilst evom €f esdoege to nodinpes be
arnt eit to “stew wertte “ae cot? ae, vin i eis doldw to oelk bbitisneb) w90d ovelt eel oe e ond ,oenice To jet Bees uhied stelvoeas inane, ssi? enns13se Yoo IIe une at soruihrands ae SR
fovea “ew! $200 \yfedee eon inaqqe atedt70 Pes.
foum cdiw JeLae werd saft séeangiee of én enone hoe og yaa vi Lareneg #2 cats evredoninr nonaed rk Dae x '
fercitnen taf ef tptidad heetge-shiw « done Atty eed f
‘2021 sogninge® maley sinonelt
and didaee InorwIDLh ursy ows moxt rete? need eat el e jo neuge 8 Sede od? .etondtiT ened ts efhboq ite AoAld aawsetew eft .eoely nontio% adt-3A 38 enomioege ont tition, fapir te Snuiome ronvond. sean 8 exofze bus ,sevaeed Giiie s8ool ots aitiw bum ob2I0d sone tans neo geil ond ek BnolsiProo, off Aen qib ce) aitiwolt Wwirw iow To 2aw aciige ort spa keoago’
ote WY Stets. of onl me
= ets 2 aniomok bre Eqqi to ISA, tedd new sone ets grew ae enoitthqeo * iqruk 2 oR Soni Ansa so mh bon ‘one | stew soKotott fire amo. taelg ett boned wed a boot to ylqquue eLqme me Baw eror2 tasta 08 i seil ad? dnc Seas sartad «2 so
a
fer Qe
ne
79 contained several rhabdocoels which were present in great abundance
and at least two planarians. One of these, Planaria velata, was conspicuous among the other forms because of its dark brown Speier and lines of fragmentation. There was some characteristic variationf but most of the specimenswere quite dark. Those few “which did show a light gray were the small regenerating individuals The color is due,as Miss STringer says, to a yellowish-brown pig- ment which causes the general dark tinge, but which under a lens is surprisingly pale and clear against the almosttransparent groundwork. This pigment is arranged in very small spots, either round or irregular in shape, and lying in rows. These rowa are placed very evenly, close together, and follow the same windings. In general, they run longitudinally, but every projection of any part, every indentation, every wound, causes a drawing to-
gether, or else a cutting in two of the rowa around it. Moreover,
thruout the mid-dorsal region, there is a contraction of both rows
and spots which will explain the heavier color of the upper side. The pigment spots within the rowa vary in their relation to each
| other. They may be large and close together or far apart; they May be evenly separated or not; or they may be small, scattered
or collected in groups. Under all conditions, however, there is a fine line of connection from one spot to the next. This is some- times hardly more than a suggestion of pigment while in s ome
_ places the connecting thread is knobbed and heavy. These color
masses are all situated in the deeper portions of the epithelial
: s = —s a oe : miei)
yecishunda tae at “tnoeeng Bite Portw eTeeootsants f ateley messed <eeons To ond senstontle @
fe ee nwoug? MBA @72 Be SnuBoed samo nextvo od? = : ae
vesoneiele opi. dew ered? nok sasnongent. buh
asont teh eginp eve # tnomloege ‘end te Ae \ ‘oO! 2 oa pO doa sy CEs gil JLoREBSY J feme ens O1ow Tey - aL -niq swoatefeiveliay s of ,ayne ol EE neim aa nol sg eDitD foiny tov .synis sxasb isroneg: edt tieiedénesitegomip ev os rire apede irs éiae "oitclie- (B2GGe ttave yrev ni feprnetss el gromi¢ "S work edadtT ewes at oriiyl bas ,eceéde al or , carthntw gases st? wollok firs ‘entoged seolo wl to neitoal ong yueve stud cb isitaess innot nwo Mati ‘ )
-0} wnlWRid & esennc vow @1eve solsatnobal
<OvooI1OM 1.95 pions mao. of? To eat mt raat s
>< 4
wou Ntod To KOLTostIHOD & ei stadt ,rodped Lauxohe :
ie
; » ae ,2hia SeQgy Sag ~~ “afoo 19) 7eH¢! ott eleique Ilbw ft arin
WS
o of moige fen "iets at YIsy Swot acts niittw soge ved? oJ Laks sal to Wes Oye! esnds hres earl ors _
Heres IH08 fame oo ae vers ne , ?on 50 Des Hinges -
oe i
sects revewant .t01 2 ba09 Lin soba 18G1107% nh Be ~eroe. at eid tee oete ot 0% OHO siowt s612900n€6 z 4 Oe a
ome 8 ml @Lbelw drompag te nekseoggare Aneta ies a "oles Senet Aimer Bite hadeors a} Kesiis. anksoonnes. :
| Fal ic ‘ae :
ink Lod sige prt to arolimog naaeed ody Ae: seuss
re *
80
The smooth color was often interrupted by light gray
ines running in different directions across the body. In some pecimens, these could be seen as grooves or furrows running into jore or less conspicuous notches at the edge of the body. It is long these lines that later the splitting into fragments occurs. Often more than one or two lines could be distinguished at once and very probably in some specimens there might have been several Since Miss Stringer reports as many as thirteen fragments from a Single individual.
That the lines of division appear so early in the pig- mentation and skin is noteworthy, since in some species the in- ternal divisions are laid down before the external are very prom-
inent.
Planaria maculata minor nov. var.
In the many collections which have been made in the
past, Planaria maculata has appeared often and in large quantities. the situations in which it lives are necessarily varied, and often in many respects they are entirely opposite to those where it has been found previously. Then, too, the immediate make-up of a pond Stream generally changes somewhat within the length of each season, and much of this change is detrimental. Another point to
> considered is the lack of protective details, for, from many
f its enemies it has no escape. A summary of these conditions
ill explain the very apparent differences in structure among the
tndividuals of even a single pond. The variations are mainly
ev shit vd ee rerthe aon soled i
te, ia 7
mon AL wYhed Ory Suoton cru he bee (eek Ce |
otnd gti: awe) “O cevonay ee Leased beat noes av DP Si 21 shes BF to eee eke th senozen, it qe - a 7 ae ~et008 ethbreenh of6) Rey ete bee vated darts
“
no fa here itabfe.oe jis eentl awd %.
> - ¥ isnaves seed ova ¢eula SRS Rpeeioege mee RE
vk agora? were 68 (ie 88, ae teges
ines ca ~fegde noreryih te abet ‘end “ dio. de toeGge. snes it porte” (Ut seeh Fon ef
ited py ain tuenttxe ene esobed moh Dinl waa ) >; y :
.U8y » von osm eesktams avons
ny, ni ofan bed. orert fos ancnoes! Ter nem ods iat
ot so Bet feito aNaiege Bart rege ry
Fs, ai ) Liveeesoen aan eevil va otete ni
Ms y ' rT)
het ft! sneetw aeonttl Gh Se i20gye gisui 212; Bs ers = . a
soc s to gu=oxant ofeihori aire gear not 1 feweae qa } 7
fone eo ahaa ‘Gre pose Ae freee asnuadts vss
titeg savers is neinindeds al be) aj 6 ; a oes eee thi GE NON, sti wror Een Re ont ‘odd Bi Be
-; ae wa. ye unOPiIws, Seats te \nedeesncr * A aigaoes on art ot aid “| ea be ae:
ort? _orbene, eieouts? a a! bebe aaa a oe
te
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ee ‘M : 2
sa} Pee ee al
. 81 those of size, shape, and color, and since a very large percent-
age have suffered mutilation, there are always many specimens which show parts in some stage of regeneration. Thus structures iay be altered within wide limits and the animal still be fairly typical. For these reasons, when many planarians from the Rock river showed small eyes, the fact was hardly noticed, and it was mot until large numbers revealed the same character that special attention was given to it. Several hundred specimens were t aken from different places along the river, all with this same dis- tinguishing mark. Other collections in the Mississippi river, at Eitener, Minnesota, at Fairport, Iowa, and also in the adjoining ponds showed the same detail. In most respects, the characters
are clearly those of Planaria maculata. The variations are of the
same general nature, the habitat the same, the conspicuous differ- ence being only in the size of the eyes and in the surrounding Pigaent. Exact measurements were taken of the eyes in a few specie mens from every collection and approximate comparisons made for Several thousand more. Therew ere always to be found a number of individuals with clear white regions, lacking entirely any eye pigment, and there were always individuals with eyes at some stage of regeneration. These were never taken into account in the general results. The dark pigmented portion was measured for both length and width with some note as to the shape. From several
h dred specimens measured, the average varies between 0.113 mn.
and 0.167 mm. in length and 0.008 mm. and 0.031 mm. in width,
-inpor”¢ eneal ey re) banka MLO F, coda Bie ae Swye Vecmt evnwie on sence ey Lontnioutse Bat Amba Pet ocr te gate pute a t ud J8ive Lawler oc) Hes viel se old AOGR aff DOT. anssaiely “hoe one tinotisd <8 {be
cow Of Baim ,beod don Si Saw S00 ons. are th
inlobge Sade Wore: «Snare ee, hetnovwa Rede vt reuse J 2 tow eames ste oye eare feeed otk 27 tf -0ih sre wv. Siw Dt ew) ers aitodo ese af woving dog lealsslM ony m2 qi bigel ion Geeed isnot Ke ( oS onte Die ool gttogai at ss asgtommerto add .sloeqes geem al .lisie® enae ot? to eB Bepltsiney otT Sepa Ivo eizenasd to ti aeteotiqanes of ote One Varin e417 .@ " trefnwon' U bes Ree one to sels ents at SLoeqe wet © ti 6 v? To nédet ever a rri9uis‘uideom “ot ofam “aca l Do. Ut RARE nae. notidelios “HUM & Hileres ve Eee Ea PAG keried?, | sonom By aye vin Yferitas pniciok#l sez Qet es ity “ape lo ast mate oma Ih eo iin ¢ inners eyaw fa: 870W ots ai singer pred ates YOON e188 peent ” (Jod 40% bevawneel wow cody ety ho teamgis ya ont” lexevea noe? .ogmite edd oF Ba eson ewe Ha bye ts £
a i ah
uo S45,0 peewtad @edip’ epaaters andy Horgan & . Pee a ete so i ae
- ave *
Br
82 n general, the eyes are a fairly regular kidney-shape but the
percentage of difference between the two eyes of the individual is high. This, however, is true for all planarians. These measure ments were very nearly one-half those of an average Planaria maculata. The shape is a little more solid, bot inclined to be a crescent but always broader in proportion to the length. The position of the eye is also significant. In the river type, the eyes are always very much nearer the median line than in the common form. They also lie almost in the edge of the middle pig- mented stripe of epithelium. This situation makes their relation to the whole of the unpigmented region somewhat different from that of the common type. That is, lateral to the eye-pigment, there
is a very large irregular clear space. This is about five or six
_times the width of the eye itself, and is striking in its trans-
parency. In the common type, on the other hand, the clear region,
altho varying to some degree and irregular in outline, fits closely to the eye-pisment leaving only a wide margin of iere paenn in- tegument.
| This special character seems to be constant for the individuals found in the Mississippi river or its immediate vici- nity. Whether it is only an environmental change due to some im-
mediate biologic condition or whether it is developmental, remains
to be seen.
Te 7at
Para in ie |
al uppit apervows ne Ye aha? ‘tiaet-ene ibis.
oft Bert lsni joe
ete %o +8 GUE rit s “eine gtivaet tt
ivy @ya
bomrd . ou
riiet Ba nite oie nie Kye Dru “bene * ote sivitnl of? Po easy ene ety noite cn sat wiretap fy [lw te wrt ek soe
vit cin al eigfl) .eenge aseio- watage ts
rot: toaster 2 “4 OF Ameen Sarosaats Latooqe af
Jataumotoyeh €b 21 <del ae colt inateo > x
1 6
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angi at? gt 4 dati iagts oyte et eyu%
4) nbd ard hom arts “8% pen démer er @
.
Rial es to snihe df ay Seonlo elt eels Codk "hs a Yu Ael pee se asat stat lvdtigqa te
ciaas betnere ten oils
. a ixt egy, LO. th iy OY tervesal #2 sant egy?
'. ot} sebe bape a) Ge ~iloss? aye afd 36
els cual fagtee ented ap ede? hommes oF oclttne of ties’ Bo oped ere OF.
cr i ae ey,
heen aor «€ soVTs iggivatsearm bat ek hraro’. 2
~, ’ ~
1) San tets fat oeainontivety rls ylae ekegl
Family CATENULIDAE The family Catenulidae was created by vonGraff in 1905 to contain five genera, two of which, Stenostomum 0. Schn. and Alaurina W. Busch, had, up to that time, been grouped wnder the family name Stenostomidea, and a third, Microstomum 0. Schn. had _ belonged to the Microstomida. To these three, he added two others, Rhynchoscolex Leidy and hike old Catenula Anton Duges, which had hitherto been in a group by itself, seemingly unrelated. He took the name of the new family from the oldest genus. Two years later, in 1907, Alex. Luther added the genus Liphorhynchus, a species with very heavy pre-oral furrow. Then, on the basis of the paired excretory tubules, and in agreement with the researches of Vejdovsky (1862), Sekira (1888) and himself, he removed Mi- crostomum and Alauria, putting them together to form the Micro- _ Stominae, a sub-family of the Macrostomidae. Another change came in 1908, when vonGraff substituted the generic name Fuhrmannia for Lophorhynchus, since the latterwas already in usef. The list of genera belonging to the Catenulidae was thus 1) Catenula, 2) Fuhrmannia, 3) Stenostomum, 4) Rhynchoscolex, and this classi- fication now stands. This family is the simplect of the rhabvdocoel group.
It is characterized by the lack of an anterior prolongation of the
intestinal cavity, and by the possession of a single protonephrid-
ium. The testes and ovary are always unpaired, tho in general
they are not to be found, since periods of sexual maturity are
'
"4 nye Wray co Pred alee) ciw eT haat Bie .1is& sO momozeort? ofctite 1O eee S198 i ; Poise
iy ‘eee Boge coer thelt Sieh of Pt «
em, ar .sto8 10 ewer reo ke” eee aba ee: 7 ‘ Soe awe owt hehhbe ef .ootcty See et .sbime2<0%eiMt 4
Led ddidw oF A vidne? ad bio ods Haw ete
telaloons Vanities Qlessl yd gies Bin ' 7 ; of : *) <a
pas. tagiio arf? ott yitaet wer a):
Stage sf) S3hbe vecttint Rr ys aa =
ko edi Ry. cy. etl eg uw Jeto-e14 Yraed yaw vake te. ~ +h > tpt ar hoo. eetogu? yiode ~7M convene act SUiteaeha tour (east) aatno® , ‘snatte imtakr 2. (orl taHe Py peel t gtk 3 20% ‘ginontael ff. vatdGrk ate Himose ore sti to fa risiiet. Sree os bree a ae beiusisedde tiarwnov F* iie €o Ww i6tsval ertz eonte eudom gelun ‘t aaw Seibtnns tao. off os aittaneled 28 Losaoneiree (B muta eore 78 (e 5 mats _ > . » bee ® |
Yoo Leooolksany agg 6 Foptqate Of: @2 vient ae , it to motyaune Doty olsen he to sok as ved tueclodin ‘ ebiridqonotoeg e lan , ep ie nodapeaocs ett td fine: wie fs
fovea rey iat ore funder ieee ore vaste nae. 8
rie ¥elaeven Tener bo eotheg raed @, ‘ncisetll
id
84 e. The common method of reproduction is by budding and chains
of two, four, or six zooids are much more frequent than single individuals. Without eyes or rhabdites, almost entirely lacking in color, these forms are most inconspicuous. With good reason, have they been likened to large protozoans, and superficially, at least, hea: to be entirely without specialized Structure, always small, few in number, compared with other types they are easily overlooked.
Of the four genera, three have been reported from this
country. One species of Catenula and two of Rhynchoscolex were
collected in small numbers around Philadelphia many years AZO.
They are probably present in other places in the eastern states, but have not yet been found here. The genus Stenostomum is quite different in its distribution. Several species have been described _ from very separated localities and the genus as a whole seems to have & rather wide-spread occurrence. Itwas first described by QO. Schmidt (1888), who recognized the characters which separate it from Microstomum. He named two species and during the next thirty years eight others were added by different investigators. Up to 1905, the genus name was Stenostoma, then it was changed to Sten- ostomun, following the new nomenclature. In the United States, two European species have been identified, while four new ones have _been added. This is the most important genus of the family, ‘since it is by far the largest both in number of species and
Number of individuals. Altogether, there are sixteen species,
Ve,
{ ae eri ss =
geiacy fun Gect Aba -d @2 not toubonginem “hort
: iis e
‘Lvcle sie Sepeat sevom en eon yoal: (fan hia Jace 0: ae unio dis a Ok ebt Dey TILy aves oicendonh Jeon oun @ ee ec iiniositegia tem .<reosnigeg RAT ov B fs 4
vis ,angzoussa: hs wre ob MOTT le ylastgis od, VElSOP, BTS Tees soy ‘fle tin Doing | wits eww) Bevdouo. Scag ee ont? mee spake gww keioodt ofort : F te mw? Ana Bigae? an to ee? . ,Onm 25R6y Litas ntitete tad be vwwokw, eatin 2 aecnIa I ineée >it mh sevelg torivo ml sneceig [ip ea pan orsse- domes ett. eter Pete? nesd medi ioaeh noe’ ovar asenage ieovad snotug istatD® o ’ ud low A nie aed bid seks /inadl hot sagitiash Fart ee est +o daweanode hate -obiw nike ae hw ah ee alanatlinet tie 2 34 — _ingh dia eelosqs. owt Bordais shy . . .ctorayiceaoag treone kt Ev Poste oven = bit wee a $ } ea nysratest ae - meres, Cree | ows ,corase fee aU ott fl “weatonomen WOR: ont & ) evet gent tom ned ai dete pons sn sus jovi “( Ltommt ents te a frei sadesoneu seein od aE a a.
brs Helooge to cgenct incre sd tect seoqaal ® .
eionga noe Sein wh otaty 1 iaeeth
ie pe
5 te 5
uf ¢ tee aniighanaa — rarere —— ietee z
85 one being a salt-water form. Then, too, the feeding habits makes
it seem to warrant an economic importance. The most noticeable details of structure are the
ather large sensory pits on either side oft he head. These are unique and extraordinary in themselves and probably take the place of the Statocyst, eyes, and sensory organs of other types. The -plunt, somewhat sfiff anterior end and the protruding mouth region give a special shape and appearance to the head. The comparatively large intestinal cavity, filling so nearly the integumental sac is another conspicuous character. Altogether, these forms are worthy of more than ordinary interest. | Of the sixteen species which make up the genus, the oldest, Stenostomum leucops 0. Schn. (1848) has had the most attention. The original description was full and exact. Almost
nothing more was done with it until H. N. Ott in 1892 made a caref
4nd complete study of the histology of all the body systems,
bringing out a number of details of value for comparative work with other families. Since this form is most primitive and evidently nearest the ancestral type, all characters of structure are of especial interest. In an experimental way, several authors have made exhaustive researches. C. M. Child during 1901-2 ana 1903 published a series of five papers dealing with the develop= ment of the zooids and regulation of fission using both this Species and Stenostomum grande. His results explain, at least to
Some degree, some of the life-habits and variations always to be
TT i Cet Qt haa eit cod Tie pe ,ooneroges ohaanooe ai ut sz oe ous crite ty alrares oldmeolton
6.
“1 snOe? .Deoeed 230 shie teddies secede wee
ats OMG) FidoCong Oitn aoy Lown mt a Pa)
a ~
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rome yIoaree hat rege’
% (200m pebbustow of? Dole Bap skein 5 A
—
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i
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.
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s)
wt 4 AINE 2 q yan ceils Amt OSG? aoe te la eg, \ re” nt? Sort cart {RROE) .eeto® .0 agoorst 2 somA .%2hme 6 (ici enw tebiqisoeeh Lanigido
Riis ias a sham SORE «i $40... JH fbgeme af. aote oh
,eearaye Ye oy Lin Se ypoLosoir wid to ydu
now vvivetegws 10) onliv Bo ailesah Be. pote 6 th
baa evitining Joon 3t-aeh els sone ‘ptellio rinfostse Bo atarchenadto Iie ayt Larsaeone of, ta Bundtue Lorevee, an Innere. tom ny, s Jape sme . ine 2 =LORL pyevi ‘ HALE sn oo aodonapaey, visa scolewil end déiw priteah artisans, ovit to ov tase at aids sted gitien natealt e- ao tha aaa, soioot a of tcoul dm, whales #9 Line aie Baste vi os ayeH ER sEOLIAINED bn etbdat-oti£ BAa) vom
86 noticed. Since the asexual reproduction is the general method,
individuals in all stages of regeneration and development are to be found together. One or two of his general conclusions throw light on the laws which govern these common processes. Perhaps the most important are the following: When a zooid separates from the
chain thru injury, “complete destruction of younger parts by older, may occur, but not older parts by younger." Again, if the Tiisration from the parent is very early, the anterior portion of the young individual develops a brain regardless of its former relationships. These two facts will account for many of the half- changed shapes and conditions present in smaller specimens.
Ritter and Congdon (1900) have also used this convenient form as the basis of a series of experiments having to do with fission induced artificially or inhibited in some manner. These authors emphasized the migration of the brain ganglion and also certain Special laws of regeneration which seem to hold. Child does not agree in his findings and brings forth rather exhaustive data to prove the truth of his conclusions.
The use to which this species has been put is due partly to the simplicity of structure, and consequent simplicity of reaction, partly to eearkniens size, and partly to the abundant Supply of individuals. The distribution is very much wider than was earlier supposed. Silliman (1885) was the first to find it in the United States. He discovered it in large numbers in certain
ponds in the east. The knowledge of its occurrence in other places
Py) ye ee a oe ) ik ¢ ~_
3. a¢ ut Jromnoleveh Pipe nak Lyveneg et: sae ego
; ; gu. z : f L- We ‘3 aenormrbomeey IA iit etd Yo. ows 0 ea : te
(ys égadied s8SGEaCHG ROMPOD oats anaveg t ai OT BOTeIBTHs Pook -£ De al rgonwntter4 j Aemmor ‘lo olsgengaeeh orélgmec® ’
isyk “sieyrsoy yharthg sebfo See toe ae be ong Heb Jie vier el vreteqi erty ~srtol- a@l To see ibyesee ets -« écoleyvebh- Lagée
rn é - a to vee act tagoode Ilbr aaah owt anette
| f IW Oh-oo feived efaembmgnee ta-8 } reo 4 « a 8 Sar «tone enoe Mh teeiditint so yee cade ine nolan o ia att Ko nois ws a OR | ih sol abrae Mort of esau 1etdw nolsexds IQet ton ' Dar + PVELI A GARDE Seige: coset east “id & re" ag é , »4reterulonos oie to ert ; : Ag Ca uh) of JOG Geni ert geiceug elde doiae of ae at | ‘ — | a
; 3 Lobtgnte. sei ee esos gets’ Do aie : niente, of2 oF Lined be “este >noknenees of var _ { . “ir qehiw como wh cele se be: eer: ai
: SD at +t pee os aqui ony: See éana) sete ne
if lit Wet ath ensstates egy ai af be! rca el a pegs the a |
Meoal, sotto at shedrmgD 682 20.)
87 tame Slowly. Every few years it was reported from some new local-
ity, but not until within the last fifteen years have the collect- dens heen adequate enough to prove its presence common thruout
the country. Now it is knowm to be living in three-fourths of all the ponds wherever there is other animal or plant life. Dur- ‘ing the winter, underthe ice it seems to carry on a successful ‘existence and can generally be found at any time. Ofthe whole group of rhabdocoels, this species is the most common, in fact Dine st cosmopolitan, and it is likely that future collections will prove it entirely so.
In the way of biologic relationships, some few new Bieevations may be of value. One character which makes possible
the very general habitat is the ability to exist under varying
conditions. Stenostomum leucops is able to live in situations
where the oxygen content is extremely low and where often the amount of carbon dioxide present is so large as to kill other members of this group. This explains the fact that it may be Present in small puddles and ponds where there is almost no plant life, or in places where few animal types exist. Often, too, in cases where the water is thick with bacterial growth and disinte- grating material of all sorts, the Stenostomum is able to live long after the conditions seem entirely unfit. That they are sen- Sitive to presence or absence of oxygen and carbon dioxide is Riewn when specimens are placed in water where part of it is cleared
and fresher than the rest. They invariably find the freshest
to ets =39%ihy AL anivil od of mont at at
i 4
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; Si -toofloo od? svat Sasey neert ir? seat eit ‘tbs Be | ies in - SHOrNN? Nowe SfNERETA ext syvouy OF dyer 018
Stil tueaigq te faninn sadtto(@2 oteds +8 Z “
{itasscova a Re WHdo of smese ¢ ook en dnebam
! ‘ : , olonw Oot $20 isms? ynwe te Deol, od vilerene 4 ‘oRt mi ~tonenooa teom ef? #t aatoode wii? aoa 7 iiw etottopliiogn euyint geris ylezil ei ¢) bee eee « . ig ds , 08 vie won wet eros eqidetolinies cigoichs to yew out ag vid iveog anima foinw tefosvado Or0 .eutav . ; mov =9fme Ieinzne of viiltide ers af ennitavtin ot SBD of elde @F sgoorvel « ae 1 _ £ F afz matte syetw fine gol yfemewsxe ei D “erite Iliv-ot 48 oftel em af saoee nq Sblxoll me . sf yam vi Sate poet of? emfelaxe eid? .quow em
rity on teenies Gl. oat? etary ebrog fire soltibaq’ I
if ,ood ” )fegae .oaaxe eeqy? Lamine wa t o-verte auc ice:
} vil ot side ak rises eons? orf? on iin tol " * “tec one vee darts eine ¢loutens seit enoisipnod » oft at Ob L KOE soda. fen IayVxo: te! eoreede pexeeic el jb 2o 2¢nq esotty- 193.00 ek booms ¢
seaneod? ante tnd ‘vinainant xont 3
th We:
re = Paes es “ J Me 7 ei a
88 arts, even tho the difference be very slight, and are always to
found in the clearer portions of an aquarium.
The reaction to light is negative, tho not very prompt w definite. That is, the specimensare always on the side of the quarium away from the light but it takes some time for them to
4
find the position and many seem to prefer not t he very darkest places. It may perhaps be said that both the brightest and dark- est portions are unfavorable, and that a merely subdued light is to be preferred.
The reactions are not at all precise or prompt and the animals seer to be sensitive to general influences rather than to direct stimuli. Heat and cold in a general way seem to have almost ho appreciable effect. Small weak individuals ere found as well an Summer as in winter, large plump specimens in cold as well as in warm water, and, too, the period of sexual maturity is not so exactly dependent upon change in season and consequent change in temperature as in most rhapdecoels. It is true that in winter, ponds where a small stream of water raises the temperature, the numbers which find the warmer parts are very large, but other conditions very probably hold here, as in such places there will be more food and often since the water was fresher, more oxygen.
ks a whole, the response to any ordinary stimulus is never strong.
If the stimulus is so intense as to cause a decided reaction, it
6 generally then of such a nature as to be injurious or perhaps
fe kill.
a pony
———— ——
a ae OY etka
ae es ea &
= ee t#eteplad ers sjod wats bisa od sqedtegs . of) ‘ail Dasifoe yvlecom oe tant Boe ,eidsrvetag J eres OE oN { fia ta ton 94h anolzosses iis GIIA SeonoiJ I iewensy ¢ SV AF. aNS6 3. nin. ever of g@osa vew fexeren a ait ofoo bra tne Jae
ef. . {t¢ ae G46.
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bwact exe elewhivlinr aesew Liam. »T098Tie
~
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ytiegvam fauxea to: folneq oft 07 fins ie
ineupgeron brs coaces at egmarin noge soo hee
tango? sft eeagin et ew to maovte tteo
a opel yaey ow atnty, Souruew- erty bak
er ne te et | od .aynwle ors bres aerigila yuev od sane : ammisaups aa to enat 40g ee of Taos (New JON on? ,@visaspen et re og nol sone | te old mo eyewia ova aneminege. ari ah a a
“Ne ie : *
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St e@kpueet Debineh s eguan of as eene dnd oa ak aus a
sed nt 6 avoluiinl ed os 20 onusen. ry dove 16,
ynoite naved @L sakvobie) papstter0 Yt oz 2 odcgee’’
a
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pie wi
(= e i alkali i:
ie’ iy
89 The food relationships are more complex than appears
at first. How many enemies there may be is hard to ascertain. That the Stenostomum becomes the food of other species is not clear Since their bodiesare entirely of soft parts easily disin- tegrated. They seem not to be hunted down by other forms to any great extent, except in the case of some few fishes which woulda anyway easily take them along with other microscopic species.
en, however, the body structure is disintegrating, the protoplasm ic content within the rhabdite-bearing integument is good food for almost any form. They can hardly be said to form any conspicuous part of the food of any animal. The food they eat is of much more interest and importance. To some extent they are scavengers, eating the disintegrating organic material so plentiful in the surface of the bottom-mud, or entangled in masses of filamentous algae. They are voracious hunters and can nearly always be found working their way, truly worm-like, thru the sort silt, systematic- ally seeking out every bit of available nutrient material. They also evidently swallow much indigestible matter, as after a period of feeding in such a Situation, the intestine will be almost black and latert his residue will be extruded thru the mouth, some- times a little at a time, and often in quite large masses. That this common form plays a large part in helping to keep clear the bottom water is very evident. The small algal swarm spores, volvox, euglena, and the like, to some extent, are eaten but are
probably more or less unpalatable. The food which is the most
ies SoS tt oa = bi ‘ eA | a‘. oe | pana hove = ng Be yoy : eieecge rutt xelgeon etc eu eqhaed iielet e oy, eG a iadroes of Bast ef o¢ vem osede tetmorio ve i jon :ai asidege “erie to hook ony womoved nuto ta aid - . -tielbh yiteas gee tioz to yleatine eo a aehhod § oe ts . om . nA oo SCOR emdze yi nwoh Begnmy ed er ton me oe 2 ia ; is J Sluow tofrfiw@perealtt wel omé@ Te ebso ony. AF IF Lehpeqe obgdoacio!lm «edz Adty em mod?) ofa te alyolomy, om ,pntzeelcielh @f squsousise thos ort! a
Ot hoot Hoda ei tnanumertnt gulused-ertidads eds beth
: - * SViCNOLGEAOS Vine tric o? bise ed-vibisd nes vedT sae
219gHOVEHOt Ome \
: : + _ Sae xoald taomfs ed Iffw enigastni oft ~iekiaggi® » tsner ae
<> ~
fonm Yoel sew yorit hoot edT .lemina yaw To cot
x a
tnetxe omoa OT .enmessogme pee
© om Lo
edt ot Lefiitweic ca Ipiuesam oinest0 psek: Jetyesalse D's : a if ,OSM@MALLT. to neaesn nt beignatns © ,Avm-o0sI0R
ees; h P a of ayawis-viueen aro frp ateinud agokositoy Oam
cit i oe Whee
meteys wlza sttoe efi wale ,eAtL-miow yiew <vaw US
vat? ,Leiatetem treiniton oldaliava to 2id yiewe, 7a
. 2 ‘tay on todte ap .vorram elsizgaggihnl dom wollews Yigg
~Omoe {ent ete abuts Ronusaty od ‘Hin. esblaet axe
san? .assEan egrset ethyp ab aodte. i oaks a ia 8 orfs “Beto qoax el snkaviort al +1 egal a wules
(POKOTe oMLAVe i feos ont eer ya se
one tug meta 2mm winedne. ene. of — _ ‘aca sektasad ms et 9
teca ent ol salty Boot
ia >
90 conspicuous, tho hardly the most common, is made up of the larger
animal types, such as ostracods, glochidia, encrusted protozoans, and the like. Stenostomum leucops especially seems to have a lik- ing for the largest possible morsels, preferring those with a hard shell. Difflugia is, perhaps, the most common form found lodged in the intestine and is present in even rather small-sized individuals. During a few days, five different species have been seen within the digestive cavity of specimens from a single pond. The naked protoplasm of the animal part, even tho entirely drawn into its shell, is easily digested out and the comparatively smooth Spherical exterior makes a mass easily extruded. The size is also convenient, not so large but that even the contracted zone of fission may allow it to pass thru to the posterior zooids. In the Same way, Other small smooth forms seem especially desired. One example will show the tendency in this direction. An individual Was noticed swinging around normally except that the movement was a little slow. The shape, however, was conspicuous as the animal seemedto be a tiny cross, very clear-cut and éefinite. Under the
microscope, the extra structure proved to be a good-sized ostracod
lying in the intestinal cavity at right-angles to the length of
the body and by its bulk causingt he body-wall to be pushed out on the two sides till the protruded part wase qual to the other Givisions. The animal seemed to suffer no serious inconvenience tho the integument and intestinal wall were stretched to the
breaking point. Evidences of such unappropriate food are quite
ee ee 4 ‘ lee * A alt .
eo f r at
> aural afd to qo eben ef .scinies saom 4 mtd
)
enpososony Belguyuotie (pibinools pit a ‘til a eved of ensee Yilalseqee 4 va semscnee
ke
=
sg
———— a
‘Siw, shod, pnd tsOT ety .alostion TRNAS
ot uit monmos te0m ed? waadnad at alae
se |
ay hecis-{leme “peter wove of Jeeserg at ad gaisgsta "
»
1
ag awe eeisoqe In 3 eae evit PL web wet # mai : iy : aie Py a ey sixaia «2 moxt exomicoge To ytivas eviJasalie 12.
— ?
7
~f “feat ois «ove oR tonto of 3 to measlye rt *
ttcom: yLewitawadmoo acts A jue hesteog id eltane el yee . ¢ ‘ * oa
ai S858. a7] wvehwrtee Vileae eesm 8 Goetem IDise 7s
gy
; , : ae lo offs Begdardco> of? nove, Jed? thd ogywel of FOR gil
* * rs > ° rat ‘
wtsonst #6 .a@BPeos teiueceoy. ofs.o? mid? feng od. 21 wohta * - ae
ref benteaens yifsioecase weer sursad ‘fizeoms {ious tee ' a ' s) a . Inuhividat MA sqortoe lh eidt ak yornebae2 ont t. weris, MM toy Ingsevem 649 fails Sqeocne el Lsurron connie cite ntam | ‘ ae
foxiees of) 6h @hOpsiqaao o «au vevewodl ogee eit tt yeh ,stiokte 0 tte duo=nweia: exeVv . BOM unite ae
; ; ; a f - =
ACOSBI AO host ~ DRG Pot © } osvemn B12 SIG. tIKe Otte
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; santo aft of, Lap seew f*sg onontery ot
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91 common. Any rounded bard-shelled animal seeme acceptable either
in part or entire, and the Stenostomum will often attempt parti- cles entirely too large to be managed. Spiny, rough, or even slightly irregular bits are almost never touched altho they may be small and easily captured. That very large bodies can be passed thru the slender pharynx is evident, if the more or less constant dilation and contraction is noticed. When the intestinal valve is closed the the long pharynx is collapsed, it appears as only a@ narrow line running back from the buccal indentation. At various intervals, often rather suddenly, the mouth is opened, very wide, so that its diameter is nearly that of the body, then immediately the pharynx is dilated almost to a sphere, displacing the walls of the surrounding region and giving almost a globular shape to the head. It is this elasticity of the walls and enveloping par- ~ enchyma as well as the heavy muscudar contraction which gives the possibility of extended variation both in size and shape. Te
intestinal opening is also capable of enonmous distention. The
extreme flexibility and lack of cell intimacy have been mentioneé
as one of the important characters oft he phylum and the develop-
ment of such a character seems to have reached its height in this species, a fact which to some extent explains the variation in the food taken.
The types just mentioned as food preferred by rhabdo- coels also help to make that of many of the fishes. Altho it
Seems hardly possible that individuals so minute could make an
' : | aists sf sig tent ati Bs ne Svat OF SimDBe 19 30B {Rao 8. ‘
1 * Le ere nbitee enc ba om Rbsaamingh neck sates
a Oa ae oe oe a Ac
per as eked } umtie eldstqecor sgege Lanmins Darton i. ia LB 119 ‘ :
'
sisueq iqiwtis nesto lin munoseonsae ovtd: Dee
ogeve to ipa guruic® .doganen, So 04 bynal 0g |
‘am vert? emféle Petowot vevorn taamieceun wrist
6d eo netbhod synel "16 seats ‘beatae ¥ tas
= retard agel x onom oc! 1s. trebive af) zane
' 4 5 . vViev Eanivesont oft net .Dovigor ee) noksonie = ; re re vite ab euseqgs ti ,boacali« ai xeynerty anol eff r ’ et ryoy +8 slOsas re Src “* mow xoad peal ne :
| ,&hlw “tev phenmewo al tirom ont. vinetbwe teftss aa thenmt nevig ywhed ¢ io tat: vlhasen ef ne 7 9b
fiaw erty arnk fous Teh ‘ f o¢ toomle Dosall eee ante “HiUsOlp, | aoute goivig. bus nolge. wet ite
; wig 2 itgolevren he et isv tg Te siokseals eid? ak | om? wovin foliry tolitoen:nos swdvseum yveet ed? eee f oT ,ogmuia Ane exis oc ciod wefratasy tehasieelte ut i . off ,nolsnesald auemnone Teo eidaqao oels ai wee beneltoen need eved vormnlini Iledpte doaf bene unt idie =yolove 5 eng bre malydg of 320 e7eg of Talo tnuznogmd Obie
arty mi ietenkeme ant: Sdintess Sag 89 mos of “notes
}
Ddect et BOarsheng heck se dencd seem jamt somes out!
Ss a»
7 iat
Jf ORSLA .AOHOET Bat! XO Ynam >< Toa ly
ae | ny s a | ve ei: ,
aH
92 yreciable difference with the food supply ofanimals like even
the smallest fish, yet they are to be considered as forming a
t of the life-struggle of such economic species. To what ex- = they offset this by themselves being devoured can only be stimated, but it is probable that they do more harm than good, Since all the protoplasm upon which they feed is of definite food “SS while them, themselves, are too few to be taken into ac- count as a supply.
Another striking detail of appearance is the difference in shape, size, and number of zooids among individuals not only of several ponds but those from one part of a single pond. This difference in appearance is the result ofthe formation of zooid Chains, and all stages of growth are to be found present at almost any given time. Tn localities where conditions of food, oxygen, ana temperature are ideal or nearly so, the chains of zooids form Yapidly, and the segments cut off are small and blunt at first, ‘tho they elongate very soon. Child (1902) very thoroughly worked out the history of the regeneration and stages thru which the sepments pass before they are themselves ready to divide. It is monly known that almost immediately upon being separated, the segments invariably attach themselves to some convenient substrat-
um. The subsequent shape, Child says, is theresult of this habit,
and the “elongation of the body can be prevented by preventing the
animals from attaching themselves". His final conclusion is of
espetial interest. "Due to attachment of animals by the tail,
ove nil siento Te eiogewe book ae . wrt h wee? 2 Betiitenao ad oy el) yerts ‘yey ght -<» Jovtw of “aebboege ocloeaues fone Se
1 ENO nite Pesrreved preted poets NG @
06, aad’ aviad. eon of) Wa fants ehitedong #
z ts =“ OL siias2eh Te «i Soest ee ape w nega a nn
“OL OfG) NeXor ox wot ag San, ev Loam re
STI LH ak) 2 ChAn ei 20 Lisieh anringese +1 ve wt ee itv tOHnd a Se es COL002 Lo'’'secrain bos nie? 4. bree ‘tle #& Ve dteq ond inet Seors
bicos te ooksairict of oe eee Sts Ol Tore pee 1 tes tn sv" Oat ov a Bis dowot 20. peande aavko eg] fo 8 va tebe evedw bel tilecol- nz
C62 Te praseto bet soe ined ae feeb? oan
gfe" b trnte bh ' Lire 63s. TIO ss siaguges fy “4 vior (SO0l) Adta® 4 aver tae ee
wy" Sliw oly oye Gite nel tesonenss eis xo j7 .Stivin of vies gowlagts gia yanks Sreteds
SS fed teal we pits 20 hog ‘mleto i peat taotl s# Sadly
sqee sf eeeadil ee re “2 1 pov Deamionws) mane stim of utd? to times ett BT ae REND
ro newer? “Yd gneve a nat hed? ent: Ber he ei nekesiteelle jantt oi Meovisedis ata
iis 96 Ve 8 homtoe te trenttoud se od) ot
93 id to mechanical tension caused by ciliary action, the form of
yegetating pieces is changed; it is a mechanical phenomenon and
at the effect of stimuli". The truncated, anterior zooia after he cutting off of the others, is a conspicuous shape very frequent- ty met with. It can never attach itself and so rather aimlessly Bins about stiff and awkward until the rounded short posterior end begins to become normal. In no other type is the shape so entirely dependent upon physiological condition or relative AZE« The number of zooids for this species is generally two, altho longer chains are often to be seen. This is due to the fact that fission planes are rarely interpolated between others and that the first division takes place before a second zone of division begins. This is quite the opposite condition from that in the Microstomum, where when fission planes are laid down at all, they very closely follow each other. It may be said that in Stenostomum the asex- gal budding is not to be correlated with any season er with en= vironmental conditions, since it is a constant process, but that
€ rapidity of the growth of zooids, i.e., the number of gen- erations developed, is dependent upon these surroundings.
Most often in ponds where Stenostomun leucops is pre-
=
sent, in larger or smaller numbers, there may be also several dif- ferent species of rhabdocoels, but generally no other members of this genus are to be found. In several of the ponds at Fairport, Iowa, however, Stenostomum tenuicauda was also present and was in
this instance the more frequent with very nearly the same life-
Le mic? ete, OR wRRELtO vd rewee soheoed 4 con Kempetedy dinebtatcon » ab ag jhopnacts. ah. “tte Dicoos “alwagme .tes mane oct. solani
a
a
o
pet vxew eqate eraeniqeaeo weak a 7930 8
fexzeioun selewn oc Soe 1 igpeadh hoesia tattered VOINASEOY ior he wie, SRP tite tnvmten on atte ort a: 90) See Of ad » Lawton
aan BVitasan + iiteog soolisetoleydg nog wijfie ,ow! vilonenem ef eoloege elt Set @Be jens tomy 36) 3 ot) 88, 630T \.noee Of .o2 newte
oft sade One eueilc noewied Béegplogtesal (fetes ots}
<@nine@ moteivin to ant Bepoen a evoled enala 2onnd
aes acrgin eric
edd meet moltsinnos ed¢teoqge \iseeto \vey ved) _iiie 28 woh Bilal ose pannt¢ aed | “seen ett sosteanetS mk pete bie ed-yam.3i G ava nity se-nceete viele defw betslesico et oF ton 4 <PRoVC1] 2eeteReo & BF Ps woake <tto kA =-ray, To secran eT oeeed) ,2hieer, ge Atwosg asia arb ohuve ay Shen? SEP jnehnegeb ei .f -exg oJ Baocth. miNNe {isn se. suerte ehaog, al peste “rib Lsvever ez! x ot an Tc) servoing, hee: hag To #7adimem wartto’ om < tered tue Pleooobetents ie 8 . nogietl te efitou ed? Te ieneves al som as
rs
Gi sew Bre teoterg onie oie
94 habits and the same environment. The two species existed side by
side. But there was a great difference in their rapidity of move- “ment. S. leucops is much more regular and quiet, holds more con- stantly to course, while S. tenuicauda shows a tendency toward a greater amount of action. In appearance, too, they differed de- cidedly, while the former is slightly opaque, the latter is quite “clear and transparent, slightly yellowish in tinge. The slender tail region is also conspicuous when taken together witht he blunt
leucops.
ee ~s =
Stenostomum siganteum nov. spec.
Tlis species was collected in large numbers in a pond with sandy bottom and clear water. The water wasvery warm at the surface and cold a few inches down. The drainage area was small, with no direct inlet, so that under all ordinary conditions very little outside water came in and since most of the water was seep- age, there was no chance for any number of species to be washed in. There was a small rivulet carrying off some surplus, but for the most part there was no current and in fact — even disturb=- ance of wind. The conditions were very nearly those of a balanced aquarium. These facts probably account for the scant number of
Species, and also for the large number of individuals of the few
which had in some manner found their way to a place in so many ways so ideal. The comparative shallowness, with sandy surround- ingf area prevented any silt from being deposited, then, too, the
amount of disintegrating organic matter was minimum. The plant
mover To VIL gay a BF bonestEEs ag rove _
ii chlé betelees geboeae gee ert .F oe
an on “4 a7
-f) Moist EL Gaae eos. .o tenneyge” at: noite te
at “S0¢Al ert .ooneqe Vigdelie al noone oi
vahrole Get spre elwelloy yiingife ine st at
oole of ¢eilw settapo: rested netw enessiqendés oa lee 5 aa ‘ 7 é Yb aa . ot spo snoga te nt hols. See , 6 .von (Wesieda mips sonsse - I 8 mi 2t6canr en iel cl Beg: bay hatin’ haw aoinegs erage os NAW Ye Tien tojew OT .netew anelo Dns eee ; cy Pete egorawh off .nwoh sedodt wel «2 Bie nov anQitinneo virenifivo Lf wwhra isnl ce sin to ss wane as os * ad iw “etew wry tc Seom eontls bee al smo 2edae HE J | | Lorbay Od of-sbicecs To tame Vie Set sora of
ee? ood sebele ieticignt geded wert rhe
“Hot 2) @uigare eos tte piikyaiss te levis iigwe a ~jnuserh nye Jor Jost of fine Udeiwe on sci ‘eas
econning 2 FeO eveod? vinren vieyv wresrw aheYaxibibe end? ta ko moda Jumpe Srl) x02 SABODO8 visser etost ‘ous
wet ond Be ebeRt vibe 20° odie aye ens og oaks
art de pol ooneg Pci aR nbedtt nai? sri
~have mea) ee Hib Morwell Lede ds
a Sone wrt ‘ne Loe wodea lassie
Da ae ee 5 San
95 ife was profuse, enough to take care of all the carbon dioxide
generated, so that the water was always clear and fresh. The inimal life was composed of a few fish, mostly Amia, a few stray turtles, microscopic forms, a small crustacean, protozoans, and
y rhabdocoels. The lack of disturbance or change and the con- ancy of inter-relationships of various species precluded great ifferences in the general fauna and flora and made possible the persistence of the same types and a continuation of the samer ela- tive conditions. The Situation in the present instance was, per- Rees; Slightly different from that of other years, since by a break in the shore line the river had swept down thru the pond carrying away the whole thing. As a result, all the pond life was new, at least only that left when the water receded. The rhabdocoels
were floated out in numbers from masses of Chara pulled up from the bottom where the water was eighteen inches deep, but they were hot to be found in any of the masses of Spirogyra taken only a few feet away. The coarser leaves of the Chara evidently har bored
lore protozoans, more organic debris or other sorts, and thus turnished a larger supply of food, but the oxygen in that region must have been very much less. No specimens were taken at the surface, they were always down a few inches where t he water was
juite cool. Stenostomun leucops was present in only small numbers
ind Stenostomum gigantea was very numerous. The food seemed to be ilmost entirely protozoans and small crustaceans, the size making
lt possible to swallow easily a number of species.
aed ony Jad greeh oerfonl res state teow “stew ord wel o Vino sede? seqne ict toa eetann ete Ye vne mb
A», d x ae ae if Not) average ates to ews! wane a feta re ofT ,c@ev) time Seeto xe cen SR bint imine hee
iy’
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‘er ,Oneonpagetd feeoalniis Lie a worvtat® “¢
Oi) ORNATIO 10 Por pT ELS to Aoat anit. : ; : .
Z tw ites
SIE tok: se a waitey te sqinfenolia aici for o70f) Bre ended Late cayy ; - ; os it we wit Yo molticoctino® B Poa gegyrcems ont? =
BOrws2 wi rreve | aft-nt nolbimveele oft jane a
nd » VO CBRiM Winey rerco to:dens meet joerwttIB9 “ iv tep- Bree Ge2* wv we syeve bad seviad ofa onkt # won saweethl frog + ile ,dipeet 8 BA «240k Loaookkiagts ort baheoos edew ott netw c3a8
mont qu heving axa lo aesenm most eisdenm ab 3am
he soya wisosbive sie ee te 2evael IwEnnoo eu ‘vine itnee avrito so el ates obmgde esom 6am coiges tate mh aegcko: ot sud yhped To viqque dey is
ott te. reais eee Ne anemdooge ov ‘ytest fog crow
GR eta Onl T weenie woddore! wet a ied acewle vsccoumm Jig wlio tr snoeo ry brie sgmuee ‘ et Aamene out ott,» *.2aommnte va on
eee eT bie
ve actoae te modes ® ¥oa i
96 The movements were invariably slow and the twistings
ind turnings 80 characteristic of Stenostomun leucops were very ery nearly lacking. Most of the specimens were made up of t wo tooids, and not a single chain of more than that was found. They vere negatively heliotropic. Their length of life has not been ascertained, as they were found only during the summer months.
A number of collections were made during January, thru eighteen inches of ice but the very shallow water below this thickness showed only a very few crustaceans. Dead fish were seen and it was apparent that very little oxygen was left in this bottom layer. The relations with other forms seemed quite simple, their only enemy was probably the fish, and the whole life condi- tion was without great struggle.
Among the other animal types to be seen in the collect- ions, this species was very conspicuous, even to the naked eye. was the largest of the nearly microscopic forms and moved quite enough to be easily distinguished. As has been mentioned, ninety ercent of the specimens were composeé of two zooids, and such individuals averaged in length from one to two millimeters. The WO parts were not quite equal, the posterior generally being a ittle the longer, so that the measurements would average about 7 to 0.9 mm. for the anterior segment and 0.8 to 1.0mm. for the goSterior segment. The single individuals were, as a rule, those hich had lately split and were of ordinary condition. They were
most always a little over one millimeter, but never reached the
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+
2
,igatie etivp Bbomeee amie t trite iPiw onoizalen | aliinoo ebil stints efg haa felt ode vid edo, ane f | relggunia Inexy s Let -tuelloo oft mb meow ed oF seas Saniige redie ors eve Deoisn one O2+ ica (BSIOLS skonnes ynew ame: Sting hevem finan sak ndepomorothn ei wor ont Be jsnin dertohenea med ent aA. Porte hogesd 2ebh : dowe dre pee ow? to ane ar Diiante enon cage:
off .evetonl Lite: ont ef one metbutepmien at Depa . A ember vlisx 1 BOG SoT SAAR ame: Tanne s2tup son 8 frieie ogerove Pisow « dione tsrhaaae asa Sankt OA alt 03° des Le oo? 8.0 in eninge 3 Boris etuw ® OR eta etoabiivbie: is at ora “ee ek? Lio caine a6 one
97
diameter was from one-fifth to one-quarter the entire length of double individual or in many instances where a separate segment was measured, was as much as one-third the length. On the whole,
this species seemed about twice as large as the comnon S$
—— =
n_leucops. In shape, these specimens were quite different from Other members of the genus. They were not so slender, but seemed more stubby abd rod-like. The ratio of diameter to length was i to 4 or 5, rather than 1 to 7 or 10. Not so agile or flexible, they were stiff little cylinders, tapering off bluntly to a short
tip. That is, from about the middle of the posterior zooid to a
point just behind the mouth, the diameter is always the same (ex-
cept at the fission plane). The region around the mouth is some- what protruded as a sort of circular lip which on the posterior ventral portion is somewhat extended, making a bulge or knob-like “enlargement at that point. The dorsal anterior part is only Slightly inflated and slopes up to the anterior proboscis or lappet like front end. This is a triangular flat portion extending back behind the ciliated pits. The greatest width of this triangle
is nearly equal to that of the body in general but the thickness is not more than one-half the body depth, so that the mouth en-
‘4
dargement is accentuated. The shape of these forms generally
. ms ab 4 a ee
compa epfY VDURmR AEN otiew Ae qos ais able
nD ee
| ‘tT hte tobueeme yrew ete mk ness nbiger as
nes
4 io otneed eee Gi see spent “es canta SI eMies BB etiviw aoornpant weet mk wort po lotw ert gO Vadgmet ets Deied-bad Ge bse epee
eh a. “OTR OCMaE AOE obo eo ugthl ae eolws 2beda Se
{+* I > tary 343 é 6 ew “teu eit Site & 826 a3 este 2. : > . * ; ‘ e
i) 5 : 7 JK és Shaieiz oe 3 PiGOW Vos ,EUROR Ort; to «
| < * 7 diitanel go 3 ty ¢ Feats ‘ bi 4, o j ort — tT sont 1-feox aie 4 7 oF 7 te i ? Wy «i< o< it Ol 40 ' og I hi mei ‘tat lae a RT:
orfa’ BOOS Yitndid 2 Toned wteiniixe elds it NLaGs Ole face i? Yo eilbhin ony tueda eon’ ‘
=x.) ore a (8F vee ts } Janeth ore <athom en? ott -opwe af Ade amy Banown aoiner att , (ormite roiaed ‘ ivyosaeq mit me dside gil saloouts Yo “toe. eee ‘cit 40 spied 8 giriitem Sohmesxe Sartwenee” af vind @ SRL NOTE? het Peres art ‘dakeq tens #9 hea | [oo 6 hc Seeeivite on? oF aw sgote hous be i > wood afhiieaaee pray ies ivanebeyt @ a elit’ 4 | innad oo) eee re preens GED? 6° oct wat Dose f ; KRemtOolds “ee game Leabniis fi fied edt to eed or a io dacoey St ny meee ¢e gegen’ ybed orf ‘f.tes sia
~ S Leneaegy sry ots as beets ott) nada
£4 ee iy a: al shy ae rid:
i]
98 ds to a great extent on the amount of contraction or expan-
sion but here the rather unwieldy body is never to a large extent tltered. That is, the animal is flexible and capable of contract- ing within somewhat narrow limits. The most contractile portion is, of course, just hehind the mouth region where the extreme flexibility of the pharynx demands heavy muscular action, and this t is much more thoroly developed than that of any other spe= Ries. Such a condition can be correlated with the heavier kina of food. The regions of greatest contraction show clearly in the preserved material, where the anterior t ip and pharyngeal regions are drawn back into the body integument.
The color appears quite white. Since the body is heavier and thicker than most forms, it is opaque and not at all transparent. The heavier integument and thicker layer of paren- chyma obscure the intestinal contents and also the intestine itself, so that there is no chance for any color to shine thru. Against the dark background of water, these individuals stand out strikingly.
The integument is, of course, a one-celled layer, a little heavier in proportion than that of other species. It is not so transparent as might be expected, due to the rather solid mtside cell walls, but in most respects is not very different from the general type. The thickness varies with contraction.
In life, it is about 10 , in mounted sections it is close to
17.5 over all the body except the anterior and posterior ends,
a a
Dek a ee See ee Se
tro fboste elauhivibar see porto to hhvotwained _ , ‘ at ° = - ie
g e by is 5 oe Agee oa aoddgertasg Yo torond me v Py
nod Ino. Aebsanaitnioe, toon ott we) worn
sitKs ets enete noise piteOm tty Bmbted a ig bam, .woliae taic>ever Yee ae? aznyuang ong i , le 7 ; sea teted wre + ¢2 may Beqelyveb “dor0As ot
—s te '
init waivnesd | tlw Aatitorwen. ed mad 023 LDng8 ;
—
at? mi viltwelo woe noivetadned seaseum Se) anced,
Enoige: Lleepmy iiic See gh? soltetarg arty atuchy lek
Jneoupetat vhed ede ofek ks &
afirtw o% Lip ois al *eJ00 a » ane
Ke
tie fe %60 fre pede ef tk armed t30m nett sila
ai — = "9 o
> ¢ . anaunt To sevll Seay hee faemmoinl yetvacd edgy. at
anitreino!l «att oeie Bir S2na too fenlisasas ond |
USGS oride-ot ie Gee mot Ba nif Or ai. e*seety' 2a
B ,ioVbl bel ies-saaie (ee urOD te. ai snegegedne : ay
ei jl. s.aslosce sgrtte Han pat ange rel 20400 ods
eer wponoemne * deyter ee on
~~
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Set’ iB VAY ORE | ae egnoguen tam al su 6 ot ; wisgentneo tiv Sera imprest oa
Pat
o2 anole se a pRGhA OO
99 ® it is from 20 to 25 - That the cohesion of the cells is
a
slight is evident in such prepared material where many of the cells
we practically pushed out or even completely dislodged from their
wiginal position in the epithelium. When the whole structure is thus crowded, the cells dove-tail into each other to some extent. hey are then high columnar, but more or less irregular, almost wapezoidal, often so as to fit compactly. The portion contain- mg the nucleus is the larger and with few exceptions is the inner they form
t. The nuclei are large and stain heavily so that/fhe most sonSpicuous part of the integument. In sections, they stand out gainst the very fine delicate cytoplasm. The cilia are veryfine nd long, from 16 to 20 » They are of about the same size and re distributed evenly over all the body. They move in waves
from anterior to posterior as a general rule. The cilia lining the sensory pits and mouth indentation are longer than the others ana very even. The ventral side is not so much differentiated
is in most species and thec ilia are little different from those m the dorsal side. At one point near the posterior end, however, here the animal habitually attaches itself, the epithelial cells ire a little heavier and the cilia show a tendency to be short
ind large. Another detail not so conspicuous is the presence of
ery small, clear rhabdites;where the integument is expanded they ie flat, parallel to the surface but scattered and more or less
rregularly placed with regard to each other. Under heavy con-
faction, when the cells are narrow and deep, the rhabdites are
= -
5
(Leo oe) De waplogton. ety TORR, ml ea! Si Loo eld Yo ertaan weremetw: Lit eis im peradend Houm nt. 3 "Loans mort honhotalh vlas algmeag move We) due ;
ut onpgoonse eforw oft son. bette eee ie2xXS owed oO! dso Cepe Sree \Liet-ovat ahs s
=
yeomla “isloyeot eared ep exon Jom te
~ >
“AIBIHOD LOLI OG eit ,Vitongmog ait co Se 6e a “orgs of? 2 iY ‘Teoma wet miiw. bas negra ens feck "€ NK os ce “liveer otnvée bre eatel oun a basse vortd> Jane gSe8. cI 2. abso tas Ske oy : rnituvev sta BIfo atT wmeaelqeryo. etaor ied onkte3 Aas eo ks site étY sneds to one vesT » Of OF BE aevow rh evom vert .xybodw ent iia tevo fis aniiitl Abiie a(@ selva Ieveneg @ 62. Setwessoge aries t sent. tenet Sam eotdadnobed LIMON bra 3 co\stlas Moire ow Jom al -ebie fetiaey OHRy
corse wont 29gseRio alsert ete abfi ports) tae cayower Poo nobtpteag edg' tape taloy @a0 JA | +S ciles fnitetsiqo ee lewd? eedtersa yiteusivad | Pris. OF. ‘eee * wots Billo ed? bas
to sonedein ors et epGnpheanne on con fhaseb'* vodt? Behamgne si indvsmete erty wripetuzeod Reine * ecsl +e s4om fine pened tees tint sookure ake OF
-nos yvast enn raced route of sash :
ote eodibdedts eft am bate Kensan em |
100 erpendicular to the surface, arranged evenly as a layer on the
atermost surface, just beneath the cilia. They are even, smooth ittle rods with blunt ends and are all of the same size, and occur yer the whole surface of the body. The influence of killing and fixing agents often slightly swells them to transparent knob-like odies.
. The integument is very closely related to the muscular ystem which lies just beneath it. As Ott (1892) has pointed out, the inside, next the epithelium, is composed of circular strands while that inside toward the parenchyma is longitudinal. The Circular muscle cells are many and make a single row of almost round cells extending the length of the body. This row of cells is interrupted at the fission plane and in the region of the Ciliated pits. The several individual strands are often 20
Baht, often side by side. The cytoplasm is granular and stains eavily. The longitudinal cells are very slender strands with
the nuclei showing as tiny enlargements along at different points. They are not many in number and are scattered. ey few run lirectly longitudinally, most being slightly oblique or extending from one portion of the epithelium to the intestine orto some ther part. The layers around the pharynx and mouth have the cells ying much closer together and on the whole they are longer. (round the wall of the intestine, the circular strands and also fhe longitudinal are almost embedded among the digestive cells.
They show somewhat scattered heavily stained between the outer
ShOSC fan ome’ Smink “eas te Jip ove ana whe
Mihimetns 9 apt idg yitrpi fe yaked. Jeom je
afioo pid. eugel wsivoa tines merce ort. anon ee
, 16 $ : sy ph ¥ es 455 aia 3 + a a bb ray ee Ai Cos am 214 Be J) Mes ne if Time, et = ort oo “eee! 6 a8 ee Sopra oat .
Atoome cco SNe veet” «Bh ito ont oan
wit ILE) ees ar ayy LOO RSE Sail-Tool Oneness Of yap atoms
oe!
&
ynivuoaum aft af fetaloy viewelo yney at tn
,7n0 hegeieg har’ (SROL)) 29% GA MGS feoned taut 4 mite Selhoests to hegeqmeo el .erd feasigs orig aT) =}. faniie tiated ef sasrytlonetad ofd buewo se bt oonle To wou elqaie x Sper Drie nA BTA af,
alles 2O wet Sle? axyhed eft te djgnel edz ane
ott To notgen eft at bee onely colbeet? sdsce { q!
OS amfto ot eboress Levbivitial isvves ett actasa fre tales al at eLeosye edt .obie va"
itiw opmeowye Sebaase yew eta! algo lantbys bar
sEtniog Toe Dh dn ywiela egnemipgiaias yald ga gaie
uit wet vw esd 2808 -o2e Bike tecmurind
oma a ote soi igesm an? sot -tmifeisiqe sds To:
OBOE WAR, Vary sorte ost we. ‘di norftegod * ole hi aipante ilvotte oA oerkaree sree ita onidedghb ots {items Mehosdaw 2 c
regio. ag costed haere vibvarc boned ;
fo
—
if 101 } of the light large cells which make up the assimilative layer.
ES the intestine is filled and the small amount of parenchyma
b daway, these muscle strands are close to those of the body
1 The most striking characteristic of this system is the ecx-~ nely small number of strands or fibers thruout the whole struct- There is much less true muscular gontraction than in almost
y other family of this group and a great part of the movement of lls is due to changes in physiological condition.
| The parenchyma is extremely vacuolate and the cells
e very delicate. Most of the support giventhe different organs fi also the stiffness of the body as a whole is due to the tur- idity of these few parenchyme calls and to the watery protoplasm Bien fills the vacuoles. As Ott finds, for Stenostomum leucops,
€ Space between the intestine and body wall contains very few lls and the only material to be displaced under varying condi- ons is the body fluid. The largest mass of ee is that
St posterior to the brain and surrounding the anterior portion the pharynx. In prepared sections, this shows as a very ir- gular network with very few nuclei, many of these connecting ‘ands are broken and the cell bodies torn. The body of the cell father small but varies somewhat. The nucleus is round, stains ply, showing large granules. There are generally five or eight iger or shorter threads or processes extending in all directions | forming a connection between neighboring parts. The simplicity
this system is one of the characters of the genus and this
ft diet 2 eta lang ae
. . | |
Lod
stir f vised vt Ta Bs ort TH -S prt dedi Ley sore ww, ¢f toa SeefomsA ileus. er? ie
ee) bee eee Se
a
nv i if ‘ad #0 wo
obtain a
ow of? Fo eeed? of veo op obretye | *
is wit ed ce suye eins to oh saLbams agp saasns “toute afew Oa thon? eel fie ere dm [es me rt? noi foe tnoe Melvoeom eur seal moyen ets. to Iseq Jeet Ss haw prea 4 trig, to" ‘ soi ihwoo Isak aolots ug nt cop iade: [feo eat Beem srr lotocy N° af aenctone tee. 40 SAONEREED oF! i revig frog of, ho 260M jem a t ssi) eri o4 on ei elorw a a8 vbed oft to econ hte 2 realqgolowg yvaintaw etd? of Ane alla emyrdueded rei ¢ 20st cumossonesG wot ,8hnl? 220 OA 26% Laposy > yvaew aeptinsoos Ilew vbod Bae entiznosiui ofa moeng ~iLinvoo gaiynev tefnm boonlqelh sd of Ialsecen niytoneisa To azam seontal stT «fin : i93ne ofd pathovovtum Dor ahaa ed? of 4 -1] (%8v £8 @e awedlé tind. ,anpiioes herwsqe%g nt a mm Misitogpiroo seats Te i tp Lowe wet quav ro.kw ake lies sri ae Ved are: ae ae thod., Atoo art? has: } .
witeve Paves BE axe item. iit .cartwence ca sa as
trivia to syed ci bmroeny on ‘sedT a ket: nee pol ae
Bites
foi
Soothe, SER tk Di in2 Re epesevomg “Wo el MBS
Aa 8 ry seis Lqrite og ett yniveditgLen roentes 7 “i aie 0D a eit, ins Basi ad te nner wi |
die ig
¥ 102 pecies seems to have fewer parenchymatal cells than any other
species.
The digestive tract is the most noticeable part of
the anatomy. The mouth with its enormous stomadaeal indentation
is conspicuous. The comparative size of this hollow epithelial- ned portion is suggestive. The cilia here are longer than in
Biner parts of the integument. The mouth is really situated at
the inner end and is the point where the true ectoderm ends. It
is, of course, flexible and is controlled by a few strands of mus-
cles. In the main, however, it opens or closes as a result of
the expansion or contraction of the pharynx. The pharynx, when
expanded to its limit, reaches the body wall and pushes that out
4
ing the whole of that region appear round. This amount of en- largement is greater than in any of the other common species. In other respects it resembles them, as in the presence of gland
cells connected with the outer wall and the lining cilia. The @ntrance to the intestine is not as sharply marked off as in some Species and this opening is not so precisely governed as the mouth. A very few muscle cells surround it but they are not strong enough te act as a sphincter so that the closure is made by the pharynx altho there is a very distinct line of division vetween the phar- yngeal cells and those of the intestine. The intestinal wall is
perhaps the most specialized part of the body structure ;altho made
p of only one thick layer of cells it shows a surprising amount
Of variation. When not inflated by a large amount of food, it is
ee
oa ih hh
a ‘7 ,;
to 24mg édieolson seem ord al Teeny ovia us: cal etna Leeehee(ia Groton att ‘Wine o =lat lads iqe Ais BAS Ws wm Be fat 2 vilown Qf Agios ent la P ohne a Gi ® on4? of ¥ etedy miteg ‘ad &i eum Lo eOrnmeaale wer f£ a hellotiies ef Bap er zo fines @ Ga peoeelo wo songs 71-8 eeed il ww .«myierky ent mingtadg Ord 206 AoLlISSXS AGG. Serie oping mre Ilaw ybod ary scilors etme) ) i “168 To Res m O2AT sababot “herGs nop (ges Jets to 1 : <eeolopqe moomoo .sSertve att Le Wits ai risict $ ded x! . #6 Jo sonpesta ed ni be oltorfs osldmpnen ot oy Leilio pninti ene Bae i ten “edn on? MIDE Sian. al ws re Noonan victor 2 Jott BL fei Jesper ole ited m2 of Teaeven vise cen ‘oe fon af igsibrtono side. snone pitonde son sik yoy? cng di neo" alles | eames att Wy at #Y aselbe Ea, Cy eye ‘oe “tombe aqnddg a gooriod “nke rv. $y west capaiaicial ur ‘p & a et iiow lasdiveose! sat enters ene Bo geoife v8 eben. cela Lay waite nas & Yoke ots %e of ae tee triton gatte lige wf eats 28). elites % need bt 22 beh Yo tmpomn epral # ‘i hapa icd
eh A ae pees beret: ay aban oe “ae — my : r ?, Ova] r rs ai 7. _ /. Sa
103 thrown up into a series of rather regular folds. The outer por-
tions of the cells under certain physiological conditions shows a protoplasm very finely granular--almost clear. It is these por- tions which undergo most of the pressure and stress when the ntestinal shape varies and they generally are much narrower and faller than the inner half of the wall. This inner border is often very irregular, some cells being pushed far out into the intestinal cavity. This is caused either by the crowding of the outer margin of the wall or by the internal pressure of the cyto- plasm. For, as the assimilation process progresses, the proto- Rimenic portions of each cell require relatively large amounts of food material, generally in the shape of oil globules. Sometimes the contained mass is so large as to occupy the major portion of the cell, and gives a very characteristic appearance. Other cells | 80 Situated that only a narrow section of the intestinal surface is free may have no = material and be small and shrunken. Thus in most respects the intestina is an organ very like that of other Species. By slightly flattening the animal, the simple excreto- ry tubule can be seen contracting slowly and irregularly. It is large enough to be clearly distinguishable and its course can be
followed from the posterior part forward to the anterior loop and
then back to the external opening. The diameter is about that of
the thickness of the integument and the white color makes it stand
out against the dorsal wall of t he intestine.
aN Ee
r LO j ue “
siog Tete Of? | uaROL mn Esig 0%. wee a ae. vote eveig tines taotgeloleydd hasiee, hebens | = oeadis es $f a tpese Seomle= ~mlulnaes van of) tem eterte ora emegeig og ae seen a ‘HOT Honm ots baer i weds Ssacil soll
L is tent «itt thew ertg to besa seat 4 a Otet tem sal Dereng pited aligo ame ele
i “
: .) a
% - ; * + 7 ‘.. fo geiswor af’ qi “erise beauns ef @iet .yRe
—
<Q Ode “he sxyecoxr Lenietal ads vad I fog end?
-O7U9y OY ,coheotwoet acasom acta Lhiaiwes anes
hero. oyinl yLoyliales otigpe: flee tote Tole ‘ <
: ae
joe «6 ahledolky Ile to. sireria. wie al cL monet
to Aolstog stolLem ede ygeode od an oP hal on ec. acem
,
gee bi 155 "820. .siOastesages obsal iA Sted yiev 2 cout
‘team faa] ‘aos eet 2 Le HOLIONS: WOrr"Lans BY; Leo. weneewte Brat f Liew an, beer seins ae e1sKe on
to tend oes Cie NBQO AR OL en} satin out’ aos tents tqekea sche. Amn ees gelnesoatt vEritgts 1? «NE hone. feted Ages HAltoe tne tome og
a steko Mane ae Bei olfeitiiagrssese Ys tnelo ok oe “oa goed nee ost et paw ae2 Bibs o> ‘wiateog ates ie Smotte 2 seven it *Balamge bilge “es Sakata *t sone eigpe ogkaw art? hae 2
a) wes mY
nite sat ort or on 4
104 The reproductive organs have not been studied since
the period of maturity occurs rather seldom. The asexual budding is common. All of the specimens taken were either in the process of forming zooid chains or had evidently recently separated. Ex-
ternally, the first or median fission plane was the only one com-
pletely enough developed to be noticeable so that almost all the specimens appeared to be formed of only two parts. The reason for this is the precocial or rapid development of the organs in the first budding zone, so that the separation takes place before the organs of the next zone have become visible from the exterior. Sections of such a zoo0id chain show the relative development of the several parts. The situation is briefly this: The brain gang= lion on the dorsal side and the buccal indentation on the ventral side of the digestive tract become about half-formed before the integument and parenchyma begin to narrow in at all. By the time this pushing-off Piaeies is nearly complete, the mouth has broken
thru, the sensory pits are formed, and the last connection is by
means of the intestinal cavity which is continuous thru the pro-
‘poscis-like anterior end of the posterior zooid. In this species, such a connection remains intact fora longer t ime than in most others and it is broken off only just before the two individuals separate. Generally, in both individuals of such development, a histological examination will show the Be cdhns of another fissigf zone in the anlege of a new pharynx and another brain ganglion.
The fission plane is quite exact and sharply cuts the parts, while
; ~ ’ é : + hh i i ae tp ~~ - ~ a7 | : 7 eer. : » ie" * ;
ite Habhiis OS Noe tenis i at:
wit Leopeeet @f8 - .molle a ned sian sonal ‘ey r pay SelO%T Ott AF matt te oxew meatier onamtosgs baal sd
—
>
~<a sHagagmyoe. plsseoen clinebtwe biel. xo. =O) a YR sd | eu. oaete i: Aetbea nay ite téonle saris oe shdnwat tor od of; boat
18f AMES KT ering. owt, ylae De heme? ot of:
mi. RA {i 1¢ snomyoloveh- Bicay 26 Infood
erotay! oosig aeated apifeipyst ed? sada be B20
a ev ne
ft wo" eldlaiv emoced overt anon IRB to theemolaved eviselo % eddy wore alario bioos & “Bf, mien edb seldy videles ai roivegvgila od? ae "i Lo Ncrmy orty a OJ JAtietal Leaoorsd ont Dine ebhie Ie siotad boar ~2.Lint woth smoned jonny ovisaey
Lia te al ecuia OF 82 y0d - aaneriomenage axox af duo ods 62 algmes Visser el seésodg al noldosrags teas eft Bow Harct eu aoia ve
“tri “i avourfamos al doide “tives Lantteetet 4 aedvene airs. Al sbLooe Tei ieteoy Sit Yo ‘hos noha Moon l. pats atid, "eaento £ a 1% hoe Ee ealewa | 14 ’ fanbi webb, vi Ye eieted’ at cline. os oe vestoms eb
. eaualeveb dome to 1 Sacdbeibert dbus ate
i wy i) nedtidon, to SHainng Le ects ane Lhbw
ce
; tale i .
, oc Lang isa tection Fires Ayla we B20 biive ote erty ato wteyrente. Dire Joneipe ottup. Semele’.
a r
105 some forms the constriction is gradual, so that the adjacent
parts do not lie very close together.
Comparing this species with others of the genus, it seems very blunt and solid by the side of the more slender, agile types. The proportion of diameter to length is very much greater -han is common.
Stenostomum glandifera nov. spec.
The form given here was present in several ponds in all of which the bottom was muddy and covered with a fine layer of silt. The plant and animal species varied, but in all cases the environmental conditions were much the same. Except in one pond, the sun and wind had much effect upon thet emperature and quiet- ness of the water. Stenostomum leucops was also present with some degree of frequency. There was always either some filamentous alga or Chara, and the living surroundings were ideal for all types of microscopic animals. Most of the food material seems to be
taken from the silt and very little from other sources, that is,
this species is entirely a scavenger in its habits. Tho swimming
free when disturbed, and often at other times{ guietly gliding around, it pays no attention to any food material and only feeds when hunting thru the thick bottom debris. This accounts for the fact that the intestine is always very dark in color. But, in general the life-habits are very similar to those of related forms. In a study of the anatomical details, a few characters
are significant. The average size is about one millimeter, altho,
Od n a a Ce OO DS Of Tend Gh) Sahai = Hod Mad
BUT Os to anaise Ad kw nel pega wiws’ line ,tobne le peg ae to obsSe eff: a 0 a
Sinem tien wae ee Ags l OM ~otenmtb 2 6Ne : ay
Odge -..Vor oitniehs ee i Rebnog fatoyvee a) TAetasg saw Stee nib: ‘tees
“yal anil » Addiw Beievoo Drs-vbhom saw abi eoe
“fg ageso Ele ai joo .betanvy wealseqs Temiae naa | og SAO HE J0GRR 4. tine oofy don o8bw ote) 4 tie | =telup han emis risges ) st) paar fasTrs Atitet Dart
amos da iw insaeay oes ame agoypuel mip seornese ol wel? emda sevists eayew baw. eAedY yy
Qi: [15 “a2 leebi onsw Benibnwedines Ratvil ens iiss
at of Onpe@ Ieineyen Boel ets to 220M ita
wt Mele 084m s4djo mod eteegT Ktov, fire Eta
Biliescws Off tt htem a4) af segheyee oS elena us
nfhils htwlap yomlé sertre se pelt ire jbo Biee? vine hen pata csy Pres ne ot onde te om.
=
ik ea bbenen, Gee aE ox fee bats ‘ont
nt (tn ,soTeo ae wtbiudls av apie el sane ~anrso't Sesples to anets oJ nagiete ye etD ashe | rate. WT & .elbatey Loe tage aad to cor in intent Ot occa teed ed eae. weoriews 96
we! Rs
> ae ot ih im es Ln one
106 of course, there is the same variation as in the whole genus.
The shape, however, is more characteristic and definite. This is a very slender form with little difference in diameter. The relative proportion of length to width and depth is about one to eight, which is quite different from some others where it is one to five or six. The anterior tip in front of the mouth is much shorter than in most species, a condition which gives the head a “much shorter, blunter aspect. The shape of this end is also less pointed than is often found. The posterior portion also is short, that is, the diameter of the pody remains the same to a point about one-fifth the length of the body fromthe end. They, the sloping off to the posterior tip is very rapid and this end is “nearly as rounded as the anterior end. The body, tho so regular is not at all rigid and bends easily. The color is light, except in the intestinal region which generally shows up quite dark, mak- ing a decided contrast between the anterior quarter where the head and pharyngeal portion is nearly t ransparent and the heavy body part. , The integument is very thin, delicate,and transparent,
which allows the internal condition to be easily seen. The cilia
are short and very evenly distributed thruout. They are only
Slightly longer in the mouth region. The rhabddites correspond closely with those of other forms, being very small, regular rods scattered thruout the epithelium and lying parallel to the surface.
Several are often grouped, lying side by side, but many are single.
~~ bi mei a my
_ song olédw oat a an not tne le | ttt, ophmttgh frie ot #8 tne taumeMNED aaa; tT . « sepemetlh ork Sota ~OTTED SIE oro ode ee] ide tte otle ed ise Ber ri .ef° 71 eet sie ho Gos mort dnewwttIH ¢
Honm af dover oft 10 Gace Mh gat a iaeras ont
or 2
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itis aitetd- ‘Sire ALqex yiev az pit “io kreteqy wrts-
Lire" | oe ade .ywbot etT .fioe-soliweina ed? a6 jdert ef sedoe et? 'vélene eited ota Biot: RY
Sou eb elap. iy aworte “Llexonse foliw notgan Od ' ‘oar whe SnD. “OLIoIne ety meeweedg pe
od \vnert a3) Time chp een > yee at ok ee
wrernnganses bre teste dey yee a. Reamer iio. art i 2 ) OF KOLET ODE inneent ott ® tine oy Ott wentteen caine ‘chaos \rn
WO TAR OD aed i deine ori ARO, ouour oe Soa
edo. ‘weiaget ileme yue acca ieHid sertto to. Bore Ott Ot LeL Larson gird Krew: crt Seed bere ts ti poigcie ate wen 7.t0ef OIE yo sive ernrk ot
of
uP Ee Baie a the 5 sh
OEE te nae ne
; 107 l@ parenchyma is exceedingly transparent and is concentrated in
he head region anterior to the digestive cavity. The posterior riangle between the intestine and the tip is very small and gen- rally almost obliterated. The layer enveloping the intestine is io thin as to be very nearly lacking, its presence being demon- trated only at the fission planes where it forms a mass gradually increasing and pinching off the digestive cavity.
The most noticeable character of morphology is the ligestive tract. The mouth expands into a somewhat irregular
ound opening, but does not contract to such a small cavity as in some species. The mouth indentation is a deep funnel rather heavily muscular but not so flexible as in those types which are the habit of swallowing large masses of food material at a time. this funnel leads to the pharyngeal cavity which is rather long and narrow. The wall here is very transparent and the outside cells small and almost invisible. The connection with the intest- inal portions is very sharply marked by a deep constriction. Except when the opening is somewhat expanded, the pharynx appears pinched offcompletely. The lumen of the digestive cavity is small and fairly regular in general outline. The wall, of course, is folded more or less but the folds are of nearly the same size and follow one after the other about the same distance apart. Within this wall,or rather very closely applied to the outer surface, and really a part of it are numerous masses of cells. These are a
ittle longer than wide and are scattered regularly over the whole
2.
Lis
|
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. ints -# = CN a ae ee een 2 2
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i anieae tavd ote wiivoleyria vod on? «Bog jC Ss aniod eonsgera at} aid tiomd ylunen. yy
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viort ? 9 err 96>. 8 OL pOLseinehnt devon ott icitw segs seeadd vl eh oltkxe lt of Jon Sih. . 1 3 Ia dainoinn host Do eonedl evtal ariwollage { mol sarean ad tw yttves Loosnyaaic. odd of cP UNGER NAS Viov el atid. Liew ve or iv (ossoeguyoo ef? widtetved seomte | ox rot eten | ‘Ont @ vo Heche bertneen cae ; Tee CM ot ee Jotwemne: ot wioege
(ion £1 ¢lives ae aps. ah to. rome en? .yless
wn, of) vee ‘a +h) entor ot? tad seol Att. .oeeee wpmeteDh. Sn aut ' ipods tert to aes Mie .AWWhwe Tete one 8 be idee viasoks YIO8 Sense oy 92907 Alles 20 oteden. euqramgen atte: 92 TOs
m ' e
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ven ire /
10& festine. VonGraff (1911) figures intestinal glands for Stenos-
mum ten icauda. Theseare much smaller, varying somewhat but out one-half the size and are more numerous, showing about three mes as many in each individual. They are quite flat against the face and protrude only slightly, while those of Stenostomun muicauda are heavier and nearly globular. These glands are un~ ubtedly digestive in function but their exact working has not x made out.
Other details of specific value are the special sen- ory organs. The ciliated pits on either side of the anterior
Appet portion are small and shallow compared with those of
tenostomum leucops or Stenostomum tenuicauda. They are verynear
fhe end, half as far from the tip as the width at that point. They re not so conspicuous as in most species, asthe epithelium is
lot thick or the cilia long so that the outlines are not sharp.
fhe patelliform or light-refracting organs,on the contrary, are fery distinct and appear as rather large, bright, almost irridic~ ent Spots directly back of the two sensory pits and on a line with a naterior edge of the mouth. They are not exactly round, but lave a slightly angular outline, showing thru the clear parenchyma, most like two bright eyes. The size and brilliancy of these fgans distinguishes them from the small and dull developments in ther species.
The zooid formation is another developmental trait.
he first fission plane is far posterior, cutting off about one-
fa
=.o7ere sol “Sinha, Tanisees aloe .
10) Joos wiivasay ,kieme pas sae ' Et! JHOGS BotwoRe . .aLinenn ONO oN brs ong it ven b ayes ds ie 3 Litp eig ved? » Resid done a mmojaotas& lo evade eLidwe visdgite —
ye
saw o%s behest, ssedt .meleiely yiueen baa TPs
oete tiers ond not tant nt
‘ * | ae } , e _ {s mys ere elev olilague ta ethes it : 5 im Ott To Shia ers iano athg Des silio Sata i aany Agiw hetaeceps eolliontea ie lines eted ; ih | "4 “otT sebyeolone! wp i203 SOROse “07 Oe -Trhog Jaxty ge @2biw on) sf gi? of} cos) ca Se eailgs ef san Mstoage. 260 Ai ap auogolg = | : in Jor ove eomkivng eft sat os gaol silty oft a . “RR ONT HO, bgt yaifoatTiewsigil we) | Wicks A0re ,JNRiw. ,.yrel terttet en seeped f ‘ ‘
a emt | (© One aig yidenee owi @e 36 as ying imo Vitesse goa sis yon? ethgieoy sit >To Same Miinctonexey «get: sip ihe | pakwoste wontheae nels seedy to see Letom bist eaee ad uve Segre
; sl a? moento te veh Elok Ine Sicm. ads na mot -aortesi
109 rd of the body length and second and third divisions are s eldom
und. The diameter externally is not changed until the internal ‘ts have been nearly completed. The parenchyma acts as a pro- itive cushion surrounding the partially developed brain and phar- Bana at the same time confines dnd pushes back the intestine
til only a very attenuated portion connects with the anterior oid.
The distinctive details may be summarized as, first, lender glandtlar bodies occurring in the wall of the intvatnes scond, especially large and clear patelliform bodies together with mall sensory pits; third, an extremely constricted connection
sen pharynx and intestine; fourth, a cushion-like mass of par- achyma protecting the anterior end of the second zooid; fifth, the
sry regular cylindrical shape.
a ih . — aii oe wink su :
eo! * 2, si. mis. on0 anolelyhh Bakd? Gras SeSeele “pat if ae pe Lanvotnd ono Dede Begrimto’ son 0k ‘tla “0710 8 88 @g98. dnielorio’n4 on? Brersepeee:
wii, hint hee hegefeveh ytiabsasg ‘ond
sot sesdnd ptt ooed aecengy brah orettod :
este Hae dyiw s¢conige nols1eg heté a
Otek eee roe “ous ed Yaa eliageh ovitont? £5
’ ie
cont thee ett to Ilse add al pariuiood derhod | viiaged salbod miotiliateg iselo Bas ogiak % Be KOnGenGoD hevorawinos yLemetike mp balls 3% ey FQ 8 eine bitt-nokreans A foot goniseornt
qo .(tthh gikeos baoose efy Yo Bus solasinw odd
; seqarte Inport
110 Family MICROSTOMIDAE
This family name was proposed in 1907 by Alex. Luther to contain two subfamilies, the Microstominde and the Macrostom- The former had, before this time, been a genus of the Catene ulidae but the researches of Sekera (1888) and Vejdovsky (1895) and especially by himself made a new classification necessary. The latter had been a family by itself composed of t hree genera. The interrelation of these two subfamilies was made on the basis of the paired excretory tubules, simple pharynx, and ventral mouth. The main differentiating characters are the presence or absence of a Preoral intestinal diverticulum and the habit of asexual budding possessed by the Microstominae to a surprising degree and not at all in the second group. , Microstomum caudatum Leidy 1851 The Microstominae contaiins two genera, one of which is found in this country, four species having been reported from one two places in New York and Michigan. One of these, Micro-
Stomum caudatum, is present in large numbers in an artificial pond
at Grinnell, Iowa. It has been taken as late as the last of Nov-
ember from heavy masses of Cladophora floating near the shore, and to the naked eye appears very much like Stenostomum leucops, which was also to be found in some parts of the pond. Almost all of the Specimens showed three distinct fission planes, two nearly Complete pharyngeal cavities andt wo otherset a much earliers tage
of development.
Of4
soittct .xald yo MOBY nk heaogen sae rma tine =a SOR OA Arte bidied ra J sori rishi eraitat). ote t6 hertey A need. ,emrs wiAd: 2004) ynevont a bos (8482) sigmell Bo. MT. MaAaeooou. mold soPtiasate wer B ober tSpentd
ot’ .eores cents to Bescgmoc Pisesk wo Witmer
ots to elfen ons no ahom na sotiimgion® owp, seeds |
ac’ .ttvow lewrev bas ,xingueda ofigmis jeeiuod
oranda NO ooneeeng od? sks axerodipto pakee
Uotucl Lewxe@e to tidead ort Ore actvolsipyis I ’ hy
tort fre songen sain recede i of vanimosaoiollt
o (HOY
fens chted ms abcee a!
Bi foldw Ie ono .eteneg Owe Ga tas oo saniinoteoio SM
mor? Beltegey assed grivart selneqe uct aerey
-e10iM .oeedd to en® ,aegidolM Gay wI0¥ ool eit!
boc Lololbitw na at asedmot aqeel at seme! wo «
“voll to 4anh ote ea etal ab reaed Hand ead tt » swol”
Brat overlay apt sear padsnort, prodqobet® Yo ceetan Yve | fo yo 2NiE, Samm Rone Se enh Ralite Rrey meats oe
to Iie seomlA. Ape oft TO. wag ome os pitciod-
vlans ows petietty ao been Poetink & womite: sees
Warr a xuollino dame 2 a erate Ow a: beta” websives 5
111 This was clearly Microstomum caudatum but in several
: or points it differed from the original descriptions of that species. In size, it was about two millimeters long, the aver-
ge of the whole mumber of specimens taken being within very narrow limits. The anterior end was not as large and round as the east- ern type. It seemed slightly pointed at the apex, being very lit- tle broader than the posterior tail end. The tail part also was somewhat Gifferent from that of the original type in that it was round and blunt and not at all pointed. The whole surface was Quite smooth and regular, showing almost no indentations at the Bins of fission. The color was a very transparent, almost irri- @iscent pale yellowish-green. The intestine when empty was also surprisingly clear, showing hardly any yellow at all, blending with the surrounding parenchyma. There was the greatest difference, however, when it was more or less filled with food material, as then the color was a distinct gray giving an entirely different inge to the body as a whole.
The epithelium is very thin and transparent, but bears extremely long cilia which are few in number, of the same size
all over the body and rather heavy. The most noteworthy details ofstructure are the nematocysts, which are very conspicuous. They are nearly one-third as large as the pharynx anda re s pherical in shape. Before being discharged, they appear to have a small, sharply-tipped cone-shaped structure within, and lie parallel to
the surface of the body. When thec ell is set off, this thread
Ad
Tonewee at dvd geetaBeraa once XE |
vets to sinh phoned Lanta teh srt
=TOV8 Od aseod Gnas ont Lito ows, tue soeshse WONG Ot: ae aintyiw arch od NOAA oiembooge *m
=e. wuts 4B birt, heres eunad © 2pm aw ~
til yey peted .xedis ang tA Behe: viotasta ag onip gray lind off oo hae si da rotnazaog wits
sew $t tects ni byyt BNL SLO “Gets nes Tht word ey eoal tub 8 Lorty ant Hatnbog ifs Setae Rive | ar Je enolietnebat.om peomta. ard woe winged s] ts is WB a acs of RTS TR aL {ev * aaw “oOleo eT O18 #Ohw vtome Aart anti aeini Srit 712819 ore twee fitiw » it brn ie vata i# volley vos YLbund goiwoda 4 Oe SROTRODY Ons Say esse! vai onorte
: e ‘1920 hoot ditw PelIi2 seel ac oncom ‘ee 325 travel ht tn Viawitoe af poivia vem aogh ease a a
m) »OLonw £ an
sie oe 38d, ore gened tae cds Yaey at out Lotesqo win ames ott to smear fil wor, one. Hotty Bi Liege
et baton “Naionows son 80m ef. cesar nonin has ¥ soem -ewoualrenoe ‘VIE ote doktm aIAKOOY ous ody vs mie _tmodrmnaty a ¢ on Sere nsec aie aad, um Saas ais bite
(iene gover of "poe ont ase Oi Lo henig ait Ans austere
-
; 112 f the sting is shot out from the tip of the cone. These nemato-
ysts are scattered very evenly over the body, and are about fifty r sixty in number. The muscular system is very slightly developed and to- ether with the parenchyma forms only a small part of the body ake-up. The pharynx is deep and broad, cup-shaped, with the mouth pening very large. When closed, however, the mouth makes only a marrow slit on the ventral side, standing out sharply against the bircle of the pharynx. The intestine is broad, its diameter being fry little less than that of the body, and the wall well marked Out and solid. It is not an even cylinder but shows a tendency © widen out at each fission plane. This brief symmary emphasizes the many minor variations which may be evolved in « different environments.
Macrostomum sensitivum Silliman 1885 One iad dial of this species was taken froma small pond in which seven other rhabdocoels occurred in larger or smaller numbers. In most respects, it very closely agreed with Silli- man*s description but in regard to a few points, added details may be of value. The rhabdites which are arranged in groups of two several, lie in large, spherical cells. In shape, these rods are long and straight, rounded at one end and somewhat pointed at the other. Generally, tho not always, they lie parallel to each other. The rhabdite-bearing cells are scattered evenly over the
surface of the body and not at all gathered into tracts. In the
A wai nadeally cielo ae ne \ . seus
=O} one 0 28 aft » OOOH ott to “ = nev tye ¢ 7 eILIT ogoeds o18 Bee. sybor eci3 te ll |
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» vito astan dicom sft .sevewod sheaalo. cansW, 25
wt? tenkayn yle-Lorte 250 Brttinase ,eble Lfpsiney tod wedeneth as) Daoud e. onitevsan of? oT. ‘eden Liew [Lew ett Aas hod ot to dertd? cunt Tamas £ ewode gud tehbaily> aewe ae ton @2 +3. aoxvlagdiqes yaeoye tebad eiaT -anelg smivei? dope $4 Jrewtiih & af Bbevievs od vam Pare eiitelsee a
a
GECL nomilli& ups isgos mumot gous ai ‘lace, 4 mock nee? aaw sebpeqe’ elds to Loubividas
ivitana ic tegrel ab besos «Leooohyerins “afte newer i |
~(Aile dite Beawye ylecolo yisy ot 483 20G80%
ynw afileted behhe ,eiatog wel 204 SaEBes at tad owt to axyvomm of ee, ene Hotty eeyL6c aris +h
ahor peers edie all ‘va ffeg Leotaedge pee ant
betatoy tacwemns fon bao ‘get ta bdbewsons =,
= ‘ti
ome od luotfermg eff yordd yetewle aan OES: gh odd teve qhive Bemettaas’ ang allse saktaaia oft nt yaw satt odd DeAedeen fle. 12 ' he’
toplasm, there are a number of large, light colored globules, laced in close proximity to the rhabdites. These globules are jlatively large and prominent and evidently have to do with the nctioning of the cell, tho whether they are stored nutriment
rp are merely a by-product of the heavy metabolism is not clear. The sensory organs are also noticeable. The eyesare ery far apart, nearer the lateral margin than the middle line of he head. The paunory hairs are very clear, sharply pointed and leem often to be bent back at right angles to about the middle, his bending may be directly opposite to the position of the cilia, | fact which seems almost impossible. In general these hairs are venly distributed, but sometimes they may be grouped in tufts of ix or eight.
The digestive system as a whole varies not at all from she eastern type but the muscular power of the pharynx seems extras Bdinarily developed. ‘The mouth with its boundary of heavy gland- ilar cells may be protruded as a cone-shaped elevation which is jonstantly being turned from side to side. The muscularity ex- ends back thru one-fifth the length of the intestine and is very onspicuous in the live animal.
The reproductive organs are also noteworthy. The
hitinous portion of the copulatory apparatus is bent, as usual,
ut the whole tip is broader and heavier than in the original dia- rams. The egss develop,a number at a time and crowd forward,
tretching the oviduct and filling the space between the intestine
ELST
teal “a
Tolnsoly heneles sAREL (.ogak ee wma a ‘ on ove selitoly, sage? anatibieds, ‘ont of : | ; it Mjiw ob ot a@ymd qylenshive Ons Inoximorg BA S :
tromkaden Dewege Clee vor. nodsocw ort Se “td »%eels Jan & ntl Lees eden yvaed ont BS] pee 1 & BOYS ent + Choo. COM eoahe ohn anagyio ¥ io onid. ofibin ert? mat? -ee Servatal wit hrs hey hog chenants re le . eey — estar
Lan
+alhbbim ods Joode -o t eefenn aitgin 38 Asad aed ' .8cile offs Lo sobvieog ent) od esteogda <itousis wee is etisd seed Latanez, al ols tesoqmi teomls a
to etius al hequot ed yar weds comttemoe Jad,
mot tie te don aeituay slow e ea apseye oviseegle i
=piJeo dade ANY tote aft Tec nevcg=saleoecm ont sud | -bnala yyaert te yiabrod ess Asie adsuor eat | co
oi fhoidw-moliavels Seqgata-9gneo.2 ee Debunstows ot}
-xe \tiualyounm od? sobia of ohbe prt Homwy |
V 6h foe oads a0aet ent to beste ons G21 we
» Lema evel aaa
et taeda eae Mis whe AH\IO. act: 5
lewan a8 cap at succes yiotelagoo dat to 8
-alo Lemigine entt ql andl -wadwoers ste ice
Deceneco Armnoerte dink. omht, 8.29. nodeme 94G0L
sitiaa@drd gat . copewddg sonqe orld. get é iat we
vi
a + ~ sway araegoenerese if at ae eee ee
' 114 nd the body-wall. This brief summary covers the main details of
iation.
Macrostomum album nov. spec.
Of the three genera which make up the family Macrostom- idae, only one is represented in the eastern states. Two species,
Macrostomum appendiculatum 0. Fabricus and Macrostomum sensitivum
have been found, as a few specimens at two or three different times. The former has also been taken at Lincoln, Nebraska, thus the distribution appears wide-spread. Several specimens of another species have been found in the same pond with Strongylostomum. Superficially, they appear like large Stenostoma, except that they are a more opaque white ané “are never seen Swimming free in the water but crawling over the surface of Phe aquarium, hunching along, as it were, one part of } the body at a time. It moves slowly and unevenly, with great difficulty, by means of a muscular contractions, slight waves passing over the body very slowly. When atrest, the animal lies “crouched and somewhat drawn up with the head bent a little to one “side and more or less of another little bend at some other point. ‘When in motion, the head is hardly ever held straight with the | body, but is constantly moved this way and that, as tho investi- gating the surrounding surface.
In size, the individuals vary from 0.75 mm. to 2.10
mm. in length, the measurements taken when the animal is as ex-
tended as possible. The width was hard to ascertain because of “]
ey as arr re —) ‘Lh St
(iP f { is } 7 . a * pd) ' + at 4 ; ‘ aw ms wT : ic elintoh.len ed @9eses yaaa Dee eee
oNge . Ven ic aurasecsan &
Meant) 3 "OB Yilmat et? gu edo foie ices. oonrte ,232 0008 OW? .hetiga mstsene eag as iio ae 4 Y, J hs . WViS SENS rpentezonory Brin aeoridal .0 tiselugt aT ‘ . > aia Yessy ii vi 40 OW? 23 CMGAL. 390s wot G& ap i. pReer Tike qiié Wise g i oxsS Heeg Oe ig aed 705 » Daoiuge +e Aiw eRe A HOES, a Rz0 i eh { tne Ge ELS TJ Ors § & rigmt Sega is nivel
a. ‘ik . ne 4 ab | s C ail a! faol To Be > A Lv nied a : wae
'o-8°%tCn ££ ea eny stads F [NORD Nae ssonege'™ :
IAVC BNILWEI9D Jie seesaw OAT AL asa] DLL we i) -¥
20 ,otew Jf Qe ,arolia aeiedonisel jt isups ont te
itiw ,viirevene faa vluols sovom 42
imfpitln ,anoloasninas waigdeon 8 10 sara wa"
ert Ad to ig 220 7 33 north a Vie fe Y16y¥ whew ets i @ diet Hned Beis ArtW 4D resin DPatwoiws
= “aio omes he Baad $£90a! “or For to deel 40.4 a aes ; = 7.
— x = = wel oo vi
¢ w! dijw idgieute Bied bes » wifes et hesd ot 6 ‘ i off -@s (cet | Fortide ow ‘eine ‘baven: Viinetente
oouthwe aki f ’ 7 ] — £* he) > La 7
OL,2 od sat arse amoett yar ecb? vate oad 4
oh atest -9 a. al Demin eae hen mabatet \nneaieet fa
ie dt ‘to ovssinted meracEs oe tuirt asw aAreiw ‘ot i aes) ) oe
115 at amount of variation, never being the same for any length of
ime. The average was 0.3 mn. to 0.7 mm. for a point about the iddle of the body. The depth was nearly that of t he width except the tail region, where there was some flattening. Asa whole, animal is very nearly cybindrical. The head end is as broad
$ any part oft he whole body, but very amenable to change, so
hat often it appears pointed. Ina lateral view, it shows a
lope to the ventral surface, making a blunt point. At about the tegion of the eyes, nearly one-fourth of the body distance back rom the anterior tip, there is a very slight constriction, which gradual in slope and does not appear unless the animal is quiet ind nearly fully extended. Posterior to this, the body diameters ire very nearly the same as far back as the lagt one-fourth, where there is a gradual and even narrowing toward the truncated tail. fhe ventral durface is somewhat flat, but the lateral surfaces ery gradually round upward so that there is only a very narrow Mtirely bottom surface. Color seems to be lacking. The opacity ypparent to the naked eye disappears under the microscope, showing mly a very transparent body. Even the outline is not as definite ind clear-cut as in many other white forms. The intestine shows somewhat darker than the clearest portions but the outline is
| almost invisible. The eggs alone are dark and thick, but show no sspecial color. The atrium seminalis and sexual pore show as very
gray-orange with smooth walls distinguishable from the cellular
enchyma. This parenchyma gives a pale greenish tinge to the
2 eS ae ev ely Ae T , gt a Fg-tlta nh, , ar ease ¥ ?
d a ae it | ON Tats D’ aggteR xa% oniae ortit aati aa Wt Jooda snton 8 So) tw TsO OF some 661 aBw ? é
a ; qnoxer de hiw wt 2 To- party wispen To HdGOD OMT iy f eolore a Sh. «andmedeal? ete aew overs aronte. : Lso%¢ éa ei Boe free! off Anoka nna a m ‘
O48 ,WBiteto ot ektanemwe giey dad vhod act
evone 25 ,wel seietal 2 ai ‘ pesaibe
inode @A ./Aal ino ld ig attlatnm oor tm
woes Sourialh yoo! oy To dsstnitieba “tneer 4
Hoiitw «0c Jones Jreite ytoy © sh.dmede satse
ip @4 shinian ore egedny et Jon aooh fine
Qoi amin ving soy. eles ata ineseod sD OMNOITRE “ CoMwel-en 31601 off an sod st en ones ada
Jllod Dedeouwnit? ett Biawed antwoutenJiteves Boa
acetage [eiegnal ats sud \anR 7 artwemoe #2
ar “iy y 7S & Vino el sexed Jats of Mas Sapo . Jogo off .eiioas ad of eapee Geled one nts #03 | SOiS, Ss tei ENDURE Sheed hake
Ji90 8° fon ®: emiieed of 260m » Ve Fea
a te
Kore otlceetns om? (ence? erdiey sania rt el sniiino at) 2 Rpaiegly, acevo eels cally on wore dag woate fine nn bh encka aene od? wt
ce WOH SRS inane, a8 Doig #2 {nctome wwiite oe
Rs ee
ae ord mayert, i ua cig vie om aes
: 116 ody as a whole.
The epithelium is thin anda clear, the cell outlines mardly visible and even the inner margin not distinct. It is of early even thickness over the body except on the ventral surface of the tail, where it is made heavier by cells specialized as a
holdfast. There is no such highly developed point on the head,
Since the animal nearly always holds the anterior end a little slevated, so that it does not come in contact with the substratun. e@ rhabdites are very inconspicuous, being small, regular in shape, and clear. They are straight rods scattered thruout the integument,to some little extent grouped together in threes or fours but generally lying in various positions, tho almost never end to end. The cilia are fine and are about the thickness of the ) epithelium, in length. They are distributed evenly over the sur- face of the body. Their movement is regular and gentle with no : heavy waves of motion. This lack of power is to be correlated | with the crawling rather than the swimaing habit and also with
the strong muscular contraction which causes a large amount of bodily twisting and turning. There is never the smooth gliding | motion So characteristic of types propelled by ciliary motion. The tail portion alone has specialized cilia. Over the upper face and to some extent dowm on the ventral side there are cilia hich are about four times the size of those of the rest of the body. They are from twenty to thirty in number and rather ivreg-
alarly placed, standing out stiff and spine-like in all direct-
Nie ae fi 2 oi ae ae! ar ois hil:
sonitine Iles eee Mots ings ints ‘aka Ws gi Jf tensed gen rulgnaia ‘ibe ron wove}
Ma ~~ i ;
sont Lovey ‘at me tqeane YRoT ed? (te Bexiltaloega at ies yd “oR VASE hit ene heer? eta #o onto, heqoleved ‘cddgatit fone on ‘in
pfav is @ Dive *tobietna oy obiod evenla ian Dir! AUstedus wets Ajiw Tondo nd SMWOD jon Bg0B +h 4 tt tatnpe A lome paied .vsowvoicenvont Vey
arly Jrouwt? henetsabe vio" SHaiaise ete yout 3 . no gests ml nerd SROs POR IH TE, JuaTxe elssif seven scouts oad ‘egnletecg aroiusy ai gatyl yi omy 1 ‘ seated a? ens Jneda om ir onlt on aL£id art = ond owe Yineve Aesudregeis ern ‘vert » fSBNB. on tiiw eltmeg Bas taieger el “gueano vos stedY ernlertee ed ot el sowoy to tee eldt nod
tiw onda Bow’ tiger piimnive oft nest? TORIES f
“to ¢netoni mint 6 savas ty sot sopyiing wiped . Ktoome acd seven ¢ exod? eeeherann: haw | wmdsont vn aEES, xe Dol degen asqy? Fo idan ‘Hyer sf) +680 “abit hes fates Bet enoe § nition eas ertiots hls Sertiew ott ne on tne | ond to ‘subx ote Be only Yo esse ois ‘soma tot 3 a“iyerrened sedan. Sores se angie te sands oe ‘see cat ~toandi Lan’ mk beste tas mise a8
; . 117 ns. They do not flex and wave as do the others but are more
eigid, thicker walled and conspicuous. They are sharply pointed yith somewhat broad, heavy bases, and are evidently sensory in
f ction. With this exception, the integumental details appear specialized to only a small degree.
T2e muscular system is important. The miscles are many cells or fibers running in a more or less longitudinal direction tho often somewhat oblique. These connect the anterior regions with the posterior end and are the principal source of locomotive power. The muscles which control the action of the head are strong- er on the dorsal side and run in a number of directions, interlacing to form a network strong enough to lift the bulky head. The action of the pharynx is also heavy and forceful, in fact this is one of the most muscular species. But with all this power of contraction, ‘the muscle strands are still so delicate as to be very nearly in- visible. They are never concentrated as to Po solid or firm, are rather single cells depending for their strength upon the sum of all their work.
The parenchyma is visible as a transparent material making nearly one-half the body mass. It is abmost the whole of the large head and extends back completely surrounding the intest- ine and reproductive organs, even filling the broad tail region. The cellular structure is evident even tho its extreme delicacy makes it appear almost a cobweb. Thecells have several long,
irregular processes, running in all directions, making 4 network
= t a Le a oe eed) 1 ea ne seeds jue qo be aa eT r 7 =e Je
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ae iieem 3.)
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woLroente Jeniovutinnel eeel 4 stom 6 nt ais &
agoiges solsetne ort fosmmep anedtl ,eepiide Jam omogel Io eonnroe Iaaioniag ers eae Bem hee sen
ates ee ae Dye ary Io nwos2o8 er7g Jorgen rolce sel oag
)
BOM aas .% Toenth To “edmrn 5 al ovr Soe ebiag ae ; . | ss ? 7. why xyiud of3 STS oF davon Boorwe Mrows Ss 4 ei aint toml mt ,ioieprot tne yeced cale ska
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nog diareise aiens sot anibregeS @fiee pla
.
a Sowinyensas # 8a oldiety aL siemrioroniag edt’,
,
to ofotn sna : pone ti st ieee eos wets ‘LLert~eag 3 afepvri orf 7s a ele SeLgned) 006 ebro 2xe, Peo sioiges Liars Apoad ite’ eden nive aie Nall ewk ae
voeehionh answers eh oft. a toe store : aol Isseves over ttn get sondea. 8
aa. : =
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WOW 190 ® privem sect 906th ite |
118 much like that of other forms but less heavy.
The digestive system is thin-walled and in all speci- mens very nearly as transparent as the parenchyma. Its boundary is somewhat irregular and the elasticity or Limit of extension less than in many species. The pharynx is nothing more than the narrowing of the anterior end of the intestinal cavity to the mouth region. It is not at all marked off from the rest of the digestive tract so that its limits cannot be distinguished. The mouth when closed is a thin slit just posterior to the eyes, when open it is triangular or roundish in shape, the wider part being anterior. The bounding wallaround the mouth is wide, about twice the thickness of the integument. It is well-defined and shows the “muscle strands which control it. The intestine itself extends far back into the tail region but not much farther forward than the mouth. The cells which make up the wall are rather large, and squamous-like, but their boundaries are not heavy enough to be distinguishable. They do not show the large oil globules found in many species and the protoplasmic content is much more fluid.
The nervous system consists of an angular brain gang- lion upon whose surface the eyes are placed. This is about one-
fourth the body length from the anterior end and leaves a broad
undifferentiated space before it, a detail which recalls the like
“condition in Macrostomum sensitivum. The eyesare dark, very small Crescents, placed near together. They call attention because of
diminutive size together with intensity of colora gainst a light
Sis
~lomys Ain ab Slee Dethinwnnd i nl daa ovises ralpusct |g ~ Seitert ees ory eet colemmine to that so vs taadenie ene aki aed? sya padrivon @. couse oat F bis
ats oF tives Leriiswoadtoeer he bas’ ol sod
t Se Set ety word Yio Bextvam lie ve. tom Bf fue
=
4? ,berle@twaniiel doc yvonne atimit est Fai 68 ate ,aeyd Of? oJ ~wtdeghoe sane bite sit? s 21 - Be yatodg sy “sentw oft ,ogerts ni. dolimes yo wie |
Oolwd Seietie ,wDhiw ef tinom oft Banwow a Liew ol barned. ois awons, tne Adntiet-Iloew «al PS »~trtmametct ote ; 1
‘ baeine Eheast antseosni’ oft atl Loxrztiros Holder |
rat? Siwaek sediias2? doum son 2rd nokged Lis} ony
’
~
piel sefiday eve TLleaw offs qu ‘bilan dodse aldee oJ ions y¥oed fon one seiinhowod siets sid oak. “e hrcr eelovoly Ife epupd add wots ton ob yadtt ,oldate eDigkt encom com el IeesInoo othmtasiael or? pre yin niead “logs me io Ss0canem oeJaye anovicd “916 Sneda e! "eh if - Bate yg" ong: #6xys ots costuse ANON B sitar a fue bne sottean erty mort dzaqed
wet els ideo Moke Linjabip i ehoted. page otnk
Lan Vee gh ennmeye ae stones wsnegeesalt 3 ‘ is to weno! wotewette tfes ved? aati?
ott « Sankag nwo to ya lenoen: eokw *
119 packground. There seem to be no other especially developed sense
organs, which is not surprising in an animal so Sluggzish in move- ment and so lacking in definite reactions.
The r eproductive organs are conspicuous because of their opaque grayness and consequent visibility. The testes are distinctly dull colored and extend from the ventral posterior region up around and forward partially Clasping the intestine.
‘The ovaries are just back of t he testes on either side. This form differs from others of the genus in that eggs develop thru the Maturation stages in two diverticula of the ovarian ducts. These are simply elastic expansions of the ovarian wall and its duct and with the enlargement of several consecutive egss it pushes fore ward to a point only a little posterior to the mouth. A number of eggs of various sizes will thus lie in a row on each side of the body, the largest posterior, down near the sexual pore and those farthest forward not more than one-half the size. The female genital pore is very large, about one-fifth the distance from the posterior end. It is irregular in shape, er ee wall.
The male pore is slightly posterior and much smaller and thin-wal-
ea. The reproductive season is during January and February.
Evidences of asexual budding were not present.
The general points of comparison with other species
are briefly: First, differences in shape. The head is much longer than Macros 6omum Sensitivum, the tail much narrower than Macro-
Stomum appendiculatum; second, the eyes are very small, much far-
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a
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—
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‘
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, | te tedmen A .ittwouw offs oF sOtnpsaog ph til-e (lee 3m
sax to oLitu dose ao wou a at eit auld iiiw aesiargs
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claret ofl ,eate Seid Tind-emo. Hans Sion Zoe ;
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| ) ‘~ sinee ong tou vias gebbhes Snirne | , Sioege wiI Atiw noe kei te Santon Levene 66
mogtod dani ef Bede eg? . pout ret nent
‘- i, “Onaga notrts novorruan adorn thes oat mvs tae . 7 bh oP a Pe) ket xtonsm «Laue toe ete ewye. ory re a)
=i | | 7 " S © K J 7 ] : hy a ; rr tl a i
AN etn me hoe
ol ry See
P 120 ler back and closer together than in either of the other two
ms, third, the male chitinous spiculesareshorter, more simple nd not 80 sharply pointed. Other details in which the members the gro@p show some semblance are the very light color, the
| hair-like cilia at the posterior end, the large mouth and mparatively simple intestinal cavity, the position of the ovar-
a
8, dorsal to the testes, and the generally spatulate tail. eo
-
ee ee
a i :
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"
121 Family PRORHYNCHIDAE
The family name Prorhynchidae was Suggested in 1862 y Diesing for the one genus, Prorhynchus, at that time contain-
ng a single Species, P. stagnalis, which had been ddéscribed by
e Schultze in 185l as a seemingly aberrent form. sO armed proboscis-like Structure/resembling the 8 tinging apparatus of
It possesses an
the Nemertinea that the early authors thought it must be an inter-
iediate type. vonGraff, in 1385, pointed out that the so-called
proboscis was merely the stylus of the copulatory organ situated anterior, and that there were really no special characters to pelate this species to the Nemertinea. Thus the integrity of the family was settled. Eight other species have been added to this genus ®ut even yet the family remains the smallest of the Turbellar- group. The nine species are Strikingly similar in a general by, the differentiating characters, however, being well defined. Wo species, Prorhynchus Stagnalis and Prorhynchus applamatus have been found in the Unitea States, the former in New York and in rackish water at Falmouth, Massachusetts, the latter in a green= louse in Lincoln, Nebraska.
Prorhynchus stamalis M. Schultze 1851 Several specimens of this species have been found in onds at Urbana, Illinois. They were taken during the latter part jt April, from the protected side of a muddy bottomed little lake. hey came with the mud or loose silt at a depth of three feet,
here the water was fairly clear with little or no algae.
Fe AS tikes Pic
i eS
' ony. 4
“bei mk Oeve onges aGw oBbsnt omueiion® Samet ime a
-chisnMOD atid dais fe sortorydaaat «208 ‘hie 8 Di raebh ageg her olde sidecmada. at .
me esaeeseoy JI. «.mriolt Jane weds dtaniins’ Ran LCE. a oa Be, To ansenegge nofent?a oct artidepeot\piwsomise oF Ios
| : s a ; i
“eins te ed faLan ¢. ‘wots evocwius vitae of? Samia
bedieo-o8 ef? tarts jvo beintog {obeL alk ae
G3 e*edsmtaedo isloegqe on vilees eiew oxeds 2 eis To weingevnmi ers eoctT ~senitiemel odd oF esi F
eins oF Bebis roed ov aelseys swede Sache
+
7 3 -~ a
wililoiusT?T eda to ¢geelinoe eft antisense viimet ete Jey s mi enmifote vipetidiause ete selscegs onke)
,Donttet iiew agried , ev: weit’ tes oataris anttnbedt es rimedase. ea aie 920, jks ac Samora “BE nt He aoe well a qemrot oid ,SeIBIE, BOS ant ; shoe, @ SE soe af? .ais sanionnge isnonlst ia a9 atennoll | 1 | PRES IaOe ou ‘sLiemage epirtoousaees,
i Syol ood éciacd batoows aidt To, euomteegs fen
cS b = Eure: a
a | yang saeco wd eee — npied hrc cdl sedomidet Mt yoxat steed Meena ebhant @ Ko obke: besoese”
yt i Jeet pendd Yo tages ae otte seook 70. fae off aa
a | ‘ores or 1 pets Hiadu
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122)
In a large aquarium of this same pond water, their
ictions were watched. Superficially, they resembled little white leeches, both as to general shape and the manner of retracting
2 whole body and then stretching it out quickly, the head free Searching in all directions. This motion wasc onstant for lengths yf time, the animal seeming almost frantic in the quick nervous motions. It crawls over the glass wall of the cquarium, covering quite a distance as it does not hold its course much of the time. It also creeps up and dow the larger stems of Chara and other water plants, but never is free-swiraming. All the movements are of the musculart type and are precise and quick. There is only a weal ciliary actionw hich has little to do with the locomotion, as it is as heavy when the animal is quiet as when it moves. The power of contraction is well-developed, the animal often drawing up to one-fourth the extended length. The average when at rest is however between one-half anf three-fourths the greatest extension. A noticeable fact is that when draw up and quiet the width is not changed, the extra enlargement having its effect entirely upon the
delth. When thus contracted, the head is not generally draw
nearly straight back up to the heavier part but is more or less bent to one side so that the form is not compact but irregular. The general appearance was striking and characteristic. MN size, there is little variation, the length being very nearly four millimeters and the width 0.5 mm.e, for any part of the body.
The shape is noteworthy, being a regular oblong with only little
. ; j : i 3 oF ve ae “ions ,18itn7 Iq Some eins Te muitaBtipa egal 7 .
aS wy alsoit baldmens’ verte ilelotaegee” *hextoag |
nitoanden DO Serna of? daw oqarts imtones, oft 7") Anon ae ot white tp re ts anitosouta nots
Be aftpast 36% taeda o enw nol eat siae enol teed SLOVIH aofng eid of ofa nears yess ) wHitsveS. ,fatisnpo of? to ftae easy orld 1BVO ek son? ests to dogm sasves aj3t Alod jor asok of OA "e110 Annem ated lo & nos 8 neyiel ed’ wok bas q
26 stm Benbwervem oft IIA .netnubwea-oudw al never tak ine ef etetT .Aaoliap base seicesg oe Ans eqKy | oldomones ef? filw ob od elviil ead doid we aokae z : _— tj we a6 Jéelop al fants on? neste vv fiwes): setlo leanings efy ,begolevyab-ilew ei noig ef jicéi te nentw e_oteve ont .tigrel bebhassxe oft aft lans3xo Jvozas sy oft sds t-semls Tas Vert-ono | jon 8k dvaiw ed feiep Srecor aes fede tat ak 92 noua Yinaiicne joe3te esi anived tnecwgueine BASED
imanh Cilasermy gon al hbaee! oft ‘.hetoerinoo song
i “Oo onom 6F ged Pung wereed on? oF qe Non a wiley amd aoe “yopaanle: See ef wwh oft sans ce bie. inetostene Hams Anixia? ¢ ey sonsusqqs isteney “2
fico yey Brtked Kspoel ats ‘Ties 161 caer B1s4EL ei:
| hod ats TO reek Gnd Ae: Qin B40 ceslw ede Bes" e slssii Yine Atiwv bh tei: nplimey nr gned axe ame i — Salo err opie ibe rca F Be: > a i. Pk a Pas
123 ye at any point and as a whole it is thin and flat, the only
ppreciable thickness being thru the intestinal region just post- erior to the middle where t he dorsal surface rounds up to some axtent. At both anterior and posterior ends the depth is exceed- gly slight. The head is sharply truncate, square with the cili- ated pits smaller than reported for other forms. The posterior half of the body is much larger and darker t han the European type, showing a greater contrast with the margin and with the head which is extremely transparent. The pear-shaped cells in the integument seem to be more Conspicuous than is usual, as they are clearly Qutlined against the rest of the epithelium. Since there are very any so that they are arranged close together. The parts of the
structure appeared clearly. A large outside portion made of a
placed smaller part round and dark in color. This evidently bears
some relation to the nematocysts and rhabdites of other species. These details are of some interest in showing the amount of varia- tion in a single forn. Prorhynchus applanatus Kennel 1388
During the month of February, in collections drom under the ice, individuals of this species appeared crawling in masses of Cladophora. This is a very different habitat with different environment from that of a greenhouse where it has been found before. The animal was noticeable on account of its pure
white color and quick, jerky movements as it crawled thru heavy
Se ae
pat ri oe Se a | asta ) 1 PS ayes ene Nino edt hol? Bde pdfiteer $1 olor avant cos
). eog deal aolppa Danigesini. ond mud aici one mos OL Gt SRT seahave Lasod ort 2 orteriw a
=he oon aiqeh 43. abae ¢ oonedeog bie sok
js
‘Oo off WSiw steope isnot Ylqtate et Bead ae i cr
“citeteog aft .enwie? sorte sob Bedsoges nats No MAOONNE o!2 marl + ode bee sepaat dom of
laity Deed ort staiw. arm ry ote ets din. searsaoo
—
|) tnevemodnt ory mi olfoo de SarGaog etT «sthewag
| 3 f [geeio oe yors en .daven ti. meds eooueigencsa
tov OuH en? cont mtr ledtdtiae: odd to saes end wt De ade 6:71 “ariteyod @g0lfo Denne tw O18 ‘rodd: 9
A 20 Shem molinog etilesin open A s“dunolo. £ Vilasiacnoose ce bepileseeg Slew etinkted sobs ee
| 6%ned Vitnmeblyo sin! snotoo mb web bag Dawes 18g % stooge terive To aad ctaet bist @sevoojmmen ed? o¢ .
& pi A “ie LOY FO rau ‘Oo vwuviwt® al faetavai emee to ons a,
P th ‘aes } mor® enoitession «al SL. to aseehy ety gti r nt aattlwete betinectin » eed soe ad? Lo elwihisvibat Atiw jatided tauwhtis vasgea! el iar if ; mec amt 22 eedty Ck HOTLINE x 46 poe 3 euig oa2 traiooos shad bbaialacte mera
Vvaosd ves: bellum th as s2nomevom shia iy + - ag oy efit gull
ae ue Rd vs.
Pokaan * #1 ls
124 pangles of the algae or hurried over the side of the aquarium jar.
In a few respects, it differs from the type descriptions. The body is not more than three millimeters long when fully extended ad about one-fifth as broad. It is extremely flat thruout the
dorsal side, the arching over the intestine being slight. The
shape as a whole is not so slender as Kennel'’s drawings, being nearly an oblong with parallel sides and nearly parallel ends.
The anterior surface is deeply notched at the point of the mouth
opening, giving the two lateral corners an almost lobe-like appear- ance. This, with the clear transparency, makes the head-region ‘conspicuous. The tail end is much more rounded and short than in other cases, which causes the whole body to seem broader. The color as a whole is much denser and purer white than in Prorhyn- chus stagnalis, showing 4 yellow tinge only over the intestine. The pharynx shows clearly its division into heavy, large secondary cells which act as a support for the four pointed tooth-like cells which work in connection with each other and re- eall the Aristotie’s Lantern arrangement in the Echinoid. They are relatively large and muscular, occupying one-fifth the body length. The method of working is striking, as the movement is
‘entirely confined to the narrow space within the pharyngeal wall.
There is little expansion and the limits of motion are narrow but
this is balanced by the drawing backward and forward of the whole structure which gives a purchase on whatever material is held at
the mouth opening. The intestinal diverticula are large but very
F
en ee
/
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Sa
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hos fan NX
el Mwiteape ea¢ to oitkrs aif none
a
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bbnstke Yliet wee givol x “eu out L Ear pot? ent Irons sat} ctbceriten i 31 . bron cor.
xT »iytle anisd an) deepet 5 oa “Ovo se 5 : . a . ib
tog ,aynive sh o* fount bp Gisv 08 soir ek si ~ 7 4
AhMe. Lessnan; Jpaew Sas e0ble leliaueg tele ae
o
of .iohrosd meee OF Ybor élotw eat Seauns dotiw a 1° ’ i
: “Mees ot oedtt etl ww iwe Das werd ome ef ele - : il ; *COSIORITS Ott NOVO Vine spats wolléd 6 oreiworts 8h
ie +
E . 7 AVVPGC Cont mebe@ivib est Yluséio ewors xervrunig eft
otatog "wot ets eb gucqaye bode gos ioindw elleo yagi
- >
3o fone dilw sol soonioo eF saee ode vliso” “Veriton ams ai gnesegdeste mmetaad e*eLie
Og ate rgd) Teng enti vaaioo - i icelaie bite oR tal él Jnemevem ade ge andaibage ai apiviow Yo boitvom's
st ilzw fg amen artes’ ‘Set idleke eteye worrean orf? oF
tid pow ee soltom Io ee EAS ont Brie ro tian f
te Olod et deryverats VOT Bute ne sensory 5 nal A xe tod oytet op anerann famdsagis oF
‘a Aaa y x = ae
a}
125 and many are not straight but curved and bent. This
from the extremely even condition in the original type.
One other detail might, perhaps, be mentioned, the 1 size of the eyes. They were of the same bright color but
not more than one-half the size given fort he European speci-
PP
oe ————————
A
ee
i a S| = ee Tae
aid dred Bie bew*ins tnd te hate
ys Lanigia eo Bt 033 tbape eee: elo 19 Mit ponodImekt BF eqedasg tigi tietens Gd 4¢Lod. tai enw of 2 Yo ete" ven?
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7 i = + ; 7 i q 7 < ne » 2
Led ee ri Oa ot,
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, is heli le ¥ =r $y5 — leogrntal “ez > ? s
Family TYPHLOPLANI DAE In 1831, Ehrenberg used the name Typhloplana for one Phe twelve genera which he described at that time as making up new class Turbellaria. Five years later he described the genus sostoma, which gave the family name used until 1905, when vonGraff itlined the general characters and gave the distinguishing limits 9 the group. He then proposed the name Typhloplanidae from the
ldest genus of Ehrenberg, for this new family,which included only
he old Eumesostomina and a few new genera described by Luther
1904). The other parts of the Mesostominae Duges were made separ- t¢ families. The Typhloplanidae stand now as composed of three ibes, as suggested by Luther (1904); six and two genera respect- vely. Of all the Turbellaria, this family is the best known. AS onGraff says, the histological work of Luther and the descriptive ork of several otherw riters have made possible a clear under-= tanding of their morphology and biology.
Nine species belonging to this family have been report=- d from the United States, all from localities in New York except wo, Bothromestoma perconatum and Mesostoma ehrenbergii, which have ccurred in Michigan and Illinois. To this list, may be added everal others.
Rhynchomesostoma rostratum Muller 1773
This is, perhaps, the most delicate of all the rhabdo-
oels. One of the very first to be described, it has appeared
sleet.
Pon ae . as ‘ ; HAC : :
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& wer, Ot) hegiipesh af vetel eipey eyi€ | at r | reviriny weiw ,G@O8L Iisnw Desew emen vyliost ote
it gtinainpriselS ed? sway bas enstiopumnio. out eahiaolqolr XT omen od? besogek) mat? imo £8 hwy Lost rs fw wisest WON SifnI Ot a tedne mie: 4s is | a sOrtdnE YI Dedlsoeoh sreneg won wet o Ana Seth goge
enw sanimossoes
Kett fo eine nade ~ e - Ps 7 ad eeidy To Besaqaos an won hasse enhlrnlqgoidqy?t api ae bang ~JOeQeut staneg owt Boe ute ( (20CL) sedjel wi begveee ay sse
Teor seeg ors af yYlimst aids ,siueliedaeT ode
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a / oavirginoess ef? bea weitte! to wacm Llacipolose te ‘Odd.
= YQ0letd Ane Yoderques ww fs i]
| ~Joogen toed oved yilme® Shit e7 asitpunlod esioage aati | a = “9049 Naot wet st eed¢ileogl wort iis wetste best
a | a todeiw . yee suegnwnrie, epeieon OM bere moronrag ; | neha Ge yaa fer eme of ,biontt il. tre uy
EVOL lp wbileiiaieiis Vsotvads erfg Dao stanitin $00 td eqcee
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Psa = reat ier —
127 gain and again in many places. It is naturally a northern form
ind is found in cold water, under the ice or early in the spring. ronGraff had specimens from a peat-bog in Rochester, which measured only 2mm. Tose which I have had came from a small temporary
yond with a muddy bottom covered with dead leaves and sticks and
a little algal growth. The water was never clear and was in the process of drying up. The length was in every instance more than
2 mm. and a few individuals were 3 mm. long. TMey were all, how- ever, very slender when extended with the anterior and posterior ends drawn out to a very long, sharply pointed tips. The whole pody made a regular spindle with the pharynx protruding only slight- ly on the rounded ventral side. The contraction of t he proboscis- like head is more conspicuous than in the European forms for it
can be withdrawn into the body back to a point even with the phar- 3 x, thus making the anterior surface the largest width. The
two rings of muscle attachment were to be clearly seen. The tail was not at all retractile. The color is noteworthy. Since the integument is exceedingly transparent, the internal parts are eas- ily distinguishable. The parenchyma is in all my specimens of a clear, pale rose, without the slightest tinge of yellow. Within this the intestine and reproductive organs showed definite outlines the wall of the intestine is somewhat gray, with very small cells hich are nearly all of the same size. Scattered among these are bright carmine-red oil globules of about double the size of the
other cells and evenly distributed over the outer Layer of the
i: Ve i ba i a A -
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"Om BorAoans yiove mi @aw dinnel ed? oes
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piry.is Vimo gxiienioug xoyyevig ort dite elhatya et inget 67
~ HOW” BF tO molsyoaetsnoo eft ,ebtea Lertqer i “02 emmet meeqc ued ore at ceriZ Pionol geen ° ‘| ect ridtiw meve Jakog s 63 aoad vhéd ad? ofnt
TsDiw Jeep sel of? sostave soldeins off oe
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me ie ;*>
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_
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‘ * ba > c
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1 eit’ to s6vel aet00 ents 390 AosestazehD “s te ; : =/ i Pon
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128 digestive tract wall. These helped to add to the general reddish
color. Of the reproductive organs, the ovary, testes, and atrium
were grayish with clear, sharp walls, and were not conspicuous.
On the other hand, the developing eggs and vitelline glands are of deep, brilliant red. The glands are compact with irregular
lobed margins about one-tenth the total length of the body and near
phe surface on each side of the body at about the middle. They
varied in size but not in intensity of color and came down to their
‘connection with the atrium as a very narrow thread. The eggs,
either one or two were matured in the atrium which formed a sort
of egg capsule. The color was lodged in the tough, thick shell
which was with all sufficiency transparent to show the yolk gran-
ules within. These yolk granules when removed from the shell were
white and clear, of somewhat varying size. One set of eight eggs
measured showed diameters varying from 22.9 to 28.8 a hey
were very nearly spherical, two diameters in a single egg generall differing not more than 5 . They lay just behind the pharynx in the heaviest part of the body and were visible even to the nakec
eye. The specimens were taken during April and all were carrying
eggs which often were extruded as the animals were isolated in
watch glasses. The first developmental stages were carried thru
put most of the eggs dies pefore the second cleavage.
This mud-loving form is, of all the Turbellaria, the
Meect ethereal, it is daintily tinged, & mere transparent shadow
against the dark packground.
Sa OOo 1 Tomato, sey Os hoe as boq fed ‘ ea
Kio TS ,Aatear YUeve ots eegioeys oun geno Jon view fae 2 Lew aqaeda eke fe io oi strat, onilfeiiv hea aygas antgoleseb edd, * ‘alogerit dein socgeco sae Chay ef Beste
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‘ ft
ALR 8 tf etetomni® owe ceqinedge wie
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Yeovaolo hnosiag ome enoted seid. ange oid Be . wis ,wltelladd? oth Lie re ah wot. aetvol—Dem anit WODp a Jue Tsang Ts << pein Fs Aidt witsaitn as 3 a
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129 Typhloplana viridata Abildgaard 1790
This is another species taken frequently during April a a few times in the summer and fall. Altho very evidently to
y identified with the European form, it varies somewhat from that, id also from those specimens already found in this country. The mals seem to come entirely from bottom water or from masses of lgae living close to the bottom. The size variations are inter- Sting. Three-fourths of the individuals were very nearly 0.5
m. in length tho they were quite often different in plumpness. The thers seemed quite long and slender in comparison, tho they meas- red only about 0.75 mm., but the relative width was less. The hape was quite different from other forms. The slope toward the ail is much more gradual altho the point itself is not sharp, that &, the posterior region is not blunt and stubby, but more slen- er. The middle part of the body is round and not so cylindrical; hen, too, it slopes into a slightly narrower neck-like portion which again rounds out into the head. This head, except for shape, hardly be differentiated from the tail end, as it does not pos- bSS eyes or specialized sense organs of any sort. It is quite ound and nearly as broad as the widest part, tapering not at all. the whole, the shape is more like some of the related genera
of this species. The anterior end is much more contractile the rest of the body and there is almost no contraction pos- ible back ofthe middle line. The amount of contraction, however,
& very much less than most nearly related species, and neither is
=
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130 here the twisting and turning which is characteristic of other
ypes. That is, the body seems stiff and solid. Thecolor varies ven to the naked eye. It depends upon the amount of green present. t is sometimes quite deep and brilliant, at other times pale and jften almost a gray. This gray is the real color of the paren- shyma and is due to absence of the pure green coloring matter. When yhere are a number of winter eggs, large and nearly mature, they pter the general appearance, giving a dull brown tinge which some- times may be quite dark.
The integument is very clear, showing not atall the eellular divisions so plainly to be seen in some forms and thus seeming almost homogeneous. The cilia are not at all clearly noticeable, as they are very fine and not differentiated. The rhate lites are very small and lie in the parenchyma just beneath the Bithelivn. They are not arranged in definite tracts but are icCattered all thru. The thickness of the integument is somewhat surprising, as for such a small form it would hardly seem proportim ite for the one layer of outside covering to reach a thickness
Buel to one-tenth the body diameter. The parenchyma is unique in wvery respect. The only cells which are conspicuous are those which ontain the bright green color bodies. Those bodies are spherical md all of about the same size and arranged in a nearly solid mass ithin the cell wall, which is in every instance so filled that the urface shows the outpushings of the solid bodies within. This
lakes the surface slightly rough. The wall, however, is fine and
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|
| 131 e@licate, partially elastic so that the boundaries of the green
jodies are visible. Most of the cells contain from six to ten
podies but an especially large one might have as many as eighteen twenty-five. These zoochlorellae are not at all regular in their placing, being scattered a few here, a few there, thruout the whole body. There were never, however, very many in the part ) terior to the pharynx, a fact which makes the head much lighter in color. Other parenchyme cells are of thecommon transparent Sevor and are hardly visible unless the zoochlorellae are so nearly absent that the- remaining cells are not obscured. The thinner material which makes up a part of the colored mass is more sharply | differentiated than in other types. Its very homogeneous fluid nature is evident. It is a very smooth light green, but whether the ; color is merely a reflection from the zoochlorellae or is an in-
) MPinsic quality developed as a result of their action is hard to
| aécertain.
| In most of the specimens taken during the spring, a number of eggs were present. These varied in number from one to ten, and it is probable since it was near the last of the winter eson that in those individuals carrying one egg,that was the last, the others having been laid,rather than that it was the first with others t@ develop later on. The one ort wo eggs always lay
in about the middle of the body, and where there were more, they crowded forward toward the head, sometimes almost completely fillin ¢
the whole anterior half of even two-thirds. They were in two rows
f ]
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132 except in a few instances where one, the oldest, occupied a posi-
tion ventral to the others and nearer the sexual pore. Since these were winter eggs, it was not surprising to find them with very thick shells. These shells were dark brown and about one-ninth ‘the diameter of the egg in thickness. For the size of the animal, these were very large, measuring 8 to 12 #£4across. The yolk cells showed thru very distinctly and were all oft he same size. They were large and few in number, giving a very different appearance than in the case of those where the yOlk mass is finely granular. With a strong light, the nucleus wasv isible as a large clear spot. Of the other reproductive organs, the cirrus could be made out large and almost transparent in the parenchyma. It was nearly as large as the pharynx and clearly showed the concentric layers of
cells in the wall. The sexual pore was guarded by a broady band
of circular muscles. The testes appeared quite large and solid.
From the several descriptions given by different authors and in the above details, it would appear that this species under- goes a greater amount of variation than is possible in many forms.
Mesostoma ehrenbergii Focke 1836
A form which I have called Mesostoma ehrenbergii has peen taken from a little pond near Urbana. It is a common Europese species which has been identified from a number of places in this country and much variation very probably exists. In several re- spects, these specimens differ from others but they seem likely to
be ther esult of environmental conditions rather than of specific
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[Encarta cape tee aye Meeeationd a
importance. They are essentially bottom lovers tho they very
quickly creep into and thru any heavy mass of filamentous algae. The length was always between three and five millimeters, which is @ reasonable average but the width anddepth were entirely out of proportion. Instead of a flat, leaf-like structure, the width was mot more than one-fifth the length while the average depth was something a little less than the width. Both these measurements, however, differed greatly in the different specimens and in the same specimen at different times. The whole shape was slender, cylindrical in a general way. The head end showed the character- istic conical, bluntly pointed portion witht he rhabdite tracts very conspicuous. It was flat and being constantly moved in all directions. The tailwas not pointed sharply but tapered to a ‘short, blunt tip. Some ofthe specimens w ere much inflated with young worms but this inflation was almost entirely effected on the upper surface alone. Ata point just posterior to the eyes, the pody wall very sharply rounded upward, making the head only a flat projection of the whole mass. The posterior end more gradually narrowed but the whole animel was exceedingly inflated. In the collection, a good many young individuals appeared. Thesew ere always more regular in outline, the head and tail ends tapering not at all and the width being nearly the same thruout the body. An- ether rather distinctive detail was conspicuous in specimens not swollen with young. This was a definite fold or angle about midway
petween dorsal and ventral surfaces and running from near the ane
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154 erior end far back, almost to the tail. This fold was marked by
hWickness of the epithelial cells and by a lighters trip andt ken darker strip. Such a fold has been described for very flat worms but not for such a round, compact type. The line of demarkation between the dorsal and ventral surfaces was also definitely de- veloped as a lighter, heavier streak. Since the ventral surface was flat, this line was never to be seen unless the animal was partially turned on a side. This ventral line and the lateral fold were very much alike in appearance and structure. The color varies froma delicate to a dark brown and is lodged in the parenchyma. For this reason, the anterior head region in which there is little room for middle cells is entirely clear. The color is not the same over all parts of the body but is concentrated in a wide dark strip down the middle of the dorsal surface. Then, also, the folds and angles Bions the edge are banked by a heavier band. Young individuals showed very pale yellow and those just born were entirely without color. The rhabdites occur in the parenchyma in close relationship with the color cells and are sharply defined and clear. They lis
in groups of six or ten or are promiscuously scattered and the head | also shows heavy tracts. In shape, they are straight rods with
| rounded ends and without any variation in diameter. Under a lens, the rhabdites give the parenchyma a checkered, rough appearance. Te intestine is much narrower than in most species of this size and is consequently more compact and also of greaterdepth. The
‘pharynx rosette is a flattened sphere, that is, the upper margin is
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135 in and the whole structure is more or less round, ag
the flat, open funnel in other genera. The mouth
‘differing from
The intestine seems not to extend farther forward
is very small.
than the eyes, a possible reason being the lack of space in the
head. So much for the more or less genergl characteristics.
The most striking detail oft he whole body structure
is, perhaps, the complex reproductive system and the viviparous
habit. The yolk glands lie next to the intestine and are opaque
to such an extent as to be easily distinguishable from the other
organs. The ovaries and testes are inconspicuous except during a
Among the number of specimens
short period of especial activity.
bearing several developing worms, two or three were especially
In one of these, twelve embryos could be seen, seven
prominent.
in the right and five in the left uterus. They were closely
packed and most were somewhat curled up, the anterior end sharply
bent on the other end. The movement was mainly a constant stirrin;
the several worms gliding over each other more or less and to some
extent changing their position in the body. The mother was fin-
ally killed, cocaine being used to produce anesthesia. By this
method, the regions of greatest contraction were made out. The
head and the region posterior to the pharynx are drawn toward the
anterior middle part which very greatly increases in diameter,
making a heavy knob-like portion. These contractions drove all
the embryos to this region where they were tightly massed. An- other specimen showed seventeen embryos on the right side and twelye
on the left. These were large, one-fifth thet otal length of the
| ai AD
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r
ow yotT ,auiety gtef od¢ ci evil one
fa dure scolsedas edd qe tela sanwomos oten 2 ra) a ‘ ; . JeeasaneS # Yiolen aw Jnemevem eff .tine sett
hie Géei © e%om terto dome s¢¢ yilaits BarIOW | “ik SaW ttocton off .vbed of al motjztacg seit SOS Bee ‘(27 XG ,atocdzeonm seoboww of besy gated onlsood ame
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| 136 siy of the parent, but were not so confined as the younger speci-
ns. The wall of the uterus is heavy and not elastic, but so mlarged as to give ample space within. All the young worms were ctive and were incessantly hurrying from one end to the other, srawling over each other in the most promiscuous way. This en- largement of the uterus pushed toward the center the intestine and what little remained ofthe yolk glands. Thetestes had almost completely disappeared so that the main portion of the body on each gide was occupied by the large transparent uteri. These, however, were extended only as far forward as the head region. The extra space needed wasgained by a dorsal swelling, the central upper sur- face being extraordinarily extended, making the shape of the animal most grotesque. The two uteri comected with each other across the middle line by uterine ducts but there never seemed to be any in- termingling of the individuals from the t wo sides. This was evi- Gently because the auct was too small to admit of the passage of So large a worm. By the time the embryos were ready for birth, the
‘duct would be stretched but the tendency would be to pass to the
exterior rather than across the pody, since in that direction the
resistance would be less. The young worms in this specimen and in the one mentioned above showed clearly two of the later stages of growth. In the first, the embryos were not long in proportion to
width, the head was not at all marked off from the body regions,
‘and the intestine was nearly clear. Int he second example, the
embryos were much more elongate, the head tapered off slightly ana
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| 137 the intestinal wall was visible as a light gray wall with many
very regular globular cells. The eyes in both were prominwnt. In the older worms, the pharynx was also fully developed and inf act more conspicuous than in the adult because of the transparency of the parenchyma and intestine and also because it was relatively very much larger. The tracts of rhabdites had also become heavy enough to be visible and most of the body structure was perfect. When, by accident, the body wall of the parent was broken, all the embryos pushed out and swam away, seemingly perfectly at home. In the Collections together with the adults a larger number of small ‘individuals appeared. Im size, these outreached all the unborn embryos only a very little. Thus it seems that the young are re- tained in the body of the mother until a very late stage in their development.
Mesostomum simplex nov. spec.
A number of specimens of this form appeared in a pond together with Mesostomum ehrenbersii and others of the same family In many respects they closely resemble the more common species. That is, the general shape, the pharynx rosette, the slender body, Fine black a ps anterior tracts of rhabdites, all very closely resemble those of othergenera. In certain details they vary to a durprising degree, being decidedly different from their contempor-
aries.
Several points of general appearance are notable. The
size, altho not at all constant, is not over 1.5 mm. long by 0.45
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| cee ee or we i OO eee
J 138 Me broad and 0.3 in depth. This is much below the average for
stostomum ehrenbergii. I shape, the difference is more promounc- a. The head end is rounded, tapering only a very little, anda
ot at all constricted or differentiated f rom t he body region. The liameter is about the same at all points except, of course, there some little narrowing toward the tail. The head end is con- wractile and as the animal moves, it is turned from side to side ind stretched in various directions. This causes more or less hange in general shape, the tendency toward a pointing of the an- serior tip showing most readily. The ridge dividing dorsal from rentral surface is well-developed around the head and this often omes into view as the animal reaches up and out. The color isa ight yellowish-brown and is as usual lodged in the parenchyma.
is very even all over the body,which is quite the opposite from
the condition in Mesostomum ehrenbergii. The anterior end, even,
5 not the least different in tinge from the rest. The integument thick and clearly defined. It is transparent and of nearly squal thickness all over except at the angle and in some special
terior portion which seems to be more sensitive. The cilia are
lot heavy and are evenly distributed over the whole surface. The habdites arescattered in a layer thruout the body just beneath the spithelium. Then, also, there are several prominent tracts arranged a narrow fan in the middle part of the head. These lie dorsal
9 the brain, running back between the eyes, but they are heavy
mough to be noticeable only far forward. They are not so con-
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ave ine “olspias oAT tinvedpesde ping? coOeeie
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iT ssoplunk plotw etd pees begodiasert y lowve. es
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evasd of wad See LONE, Hey bows a Aone 3 raeet
aa ue:
neq of Jon wa yor? Pasi ieahs set Vines igs
139 picuous as those of yesostomum ehrenbergii, where they are sharp
inst the clear background. The parenchyma of this new M. simp- is especially well-developed, taking up most of the space in
ie body. The cells are close together and there appears to be
| fluid than in some forms, being almost undefined. The con- ained matter makes only the central portion darker, and does not : ticularly intensify the wall cells. This conditions does not t all abseure the pharyns which stands out dark and heavy. Its is large comparatively and the rosette cellsa re rather long. This specieshas not been taken when in the reproductive stage. The
above outline summarizes the notable characters.
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i
Family DALYELLITDAE The Dalyelliidae have had an irregular history. Start- in 1843 with the descriptions of Oersted and continuing to the resent time, this family has been the subject of descriptive md systematic studies. Oersted named several species belonging to the genus Deristoma and then proposed the family name Derostom- BAe» Schmidt (1848), Ulianin (1870), and Jensen (1371) worked ver this family adding species and defining the genus characters as well as describing several genera belonging to other nearly related families. In 1382, vonGraff reclassified the whole group, incorporating with Derostoma the old genus Vortex Ehrenberg (1831) and naming the family from the latter genus. He created two sub- families to contain the eight genera. Then, later, in 1903, he sain renamed the Vorticiidae, making a family, Dalyelliidae, with two sub-families, the Graffillineae and the Dalyellinae named a fter the two oldest genera, respectively, and at this time also because Vortex had been used in 1797 for another form he suggested the name Dalyellina first used by Fleming in 1322 for that genus. Again in 1908 on the basis of a paired ovary he made two fdilies he Graffillidae with two ovaries and the Dalyelliidae with only ne. The latter family was made to contain six genera and sixty- one species, all European forms. Before 1911 three or four species had been identified for this country, all new. In his paper of
that year, vonGraff described eleven others, most of them taken
from the locality around Rochester, N.¥.. Thus the present con-
—
—— — —
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-—mijeqrod amar viimel? ary houpeeas net? Dow ani r ox tow> (198) noexide pos , (COVES) otanktD-, (ere 5 oimito grep att satnite pianeih-iesi: xt BBB fuser dertvo 4 pripiotes srandy lensvea anid’ “> efertw efs berttesaloes ‘Vhewnow OBL mi (fess) _redeentl xacioY exoneg Bie odd nnoJeotsd Aske ine ows Beiwend GH «tone gy wWtaal et moat vile “i 20°C Lion “ateal ,fodT .steneg Jaatic Sehililexied .yilmad x Qucd pean eehiiolinevy ed¢
te Semen osmitieyiog eds bane sacl iListew® oi? LACE OF ie emit elvy te Bae culevitoegese: eSTON9 orf’ Deteenave od ottot Sevens sod POUL at Beep eum, Jad? mt Shel ‘ai aici dN va howd gett iti: owt obam en eevee berkag ri9 olesd ont so i
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“Jxhe Rn srenep ate sbeceeo od stim sew linet
Lo aga ebfat wok ite Arsowes hid act !
ower med be. Peo whodite ae be boa ouan'3
“ited smeeeK sid aii? SoM areata
141 eption of the family is quite different from the early original
lescription.
The more general distinguishing details are the pre- gence of a single ovary and two yolk glands, a simple genital pore, and the anterior barrel-shaped pharynx without a sheath.
The pharynx is the most clear and easily seen of any sharacter. It is often slender and long, often short and nearly spherical, but generally the checkered appearance of the wall is sll-developed. It is always of relatively large size and holds tS shape constantly, not being at all collapsible. It is thus very sharply marked off from the intéstine which is very different in structure. During the reproductive season the vitelline glands nmning forward on each side of the intestine are very prominent. me Ovary, testes, and other accessory parts are often so embedded a8 tO be difficult t> make out, but always the yolk glands can be been nearly as large as the intestine itself, extending up around it toward the dorsal side. In many instances also the rather large ypaque egs is evident more or less completely filling the post- wior region of the body. The anterior end is commonly truncate mth the mouth a conspicuous whole just ventral to the very front
largin. The development of a tail-like portion is somewhat vari-
ble but all the forms show at least a tendency in that direction. he shape as a whole is much more slender in many families. The Olor ranges from almost black to clear transparency. The above
ummary mentions points in the general make-up which causes this
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c,. | 142 group to be one of the most easily recognized of all the families,
Dalyellia dodgei vonGraff 1911
This species was taken together with half a dozen other rhabdocoels from a small temporary pond which during April was up * four feet deep but which later would dry up completely unless the rains were especially heavy. It drained down into a little Yiver so was not entirely cut off from outside species. There was a muddy bottom with some algae and many leaves from nearby oak trees. The site was protected from wind by little hills so that the warmth of the sun was felt early. The special locality was : the surface of bottom mud or a small mass of algae. Either was a good hiding place as the animal was nearly black. The motions were sluggish and not constant. When at rest, the body was draw “up to one-half its extended length and seemed almost round. It was not as easily frightened as most of the others pecies and when aroused more quickly pecame quiet. One little habit was quite noticeable. Very often when the rather small mouth was opened, the front end of the head was slightly elevated to give the ventrally placed opening a more advantageous p)sition. The two corners of
the head were very contractile and were used almost like lips to
| guide particles of food into the opening between them. When the
animal was moving along, the mouth was closed and the ventral sur- face held down. The head was never turned from side to side, and the whole body was straight, keeping to a rather definite course
for the most part.
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143 This form agrees closely with that described by von
Graff from Rochester. He speaks of it there occurring more fre- quently than almost any of the others. The conspicuous characters are double arrangement of the pharynx with its especially developed papillae, the mottling due to scattered pigment cells and the com- plexity of the reproductive organs. This western type is note- worthy as showing the distribution of a species found commonly in a certain restricted locality and seems to be indicative of its probable wide-spread occurrence. A resume of its variations may be of interest.
In size and shape, my specimens are very nearly those of the eastern form but the color is strikingly different. Altho showing a sepia-browm when the animal is compressed to such an ex-
tent that the parenchyma is in a thin layer, yet under ordinary ‘conditions it is very dark. It appears evident that the pigment cells when fully developed lie so close together as to aggregate in a color nearly black. It is really a dull brownish-black, so ‘opaque as to entirely obscure the internal organs. On account of this color in the parenchyma, the integument by contrast is ex-
ceedingly prominent. It is especially thick and possesses an al-
‘most irridiscent transparency. It so reflects the light as to show
the convexity of the body surface. This gives an appearance of solidity not present in most specimens. The cilia are fine, clear, and very swift and heavy in their motion, as a result of the
of a strongly functional muscular system. The parenchyma is
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a =. —
144 That is, there is
posed almost entirely of pignent-bearing cells.
no layer of colored cells on the outside Just beneath the integu- ment as is commonly the case but most of the parenchyme cells con-
tain more or less pigment substance so that the color is scattered.
The fluid material is present but it is not conspicuous. In shape, the cells are irregular and in most respects they resemble the parenchyma of other forms. The digestive tract ié different
So covered by the pigment
from the type only in minor details. that it is not apparent when crushed out from the surrounding tissues,it shows the characteristic green of the wall cells. The pharynx apparatus is especially long, extending back thru more than one-third the body length. The anterior vestibular portion is shorter than the pharynx proper, but is of about the same diameter. The papilla are very slender and lie far apart.
The only point of note in regard to the reproductive organs is the duct leading from the uterus to the genital pore. This is extremely slender and long, a mere thread reaching up into the body mass for a distance almost equalling the main diameter. In specimens where the egg is large and ready for laying, the duct appears incapable of such extension as is necessary for the pas-
gage. The yolx glands, testes, and ovary lie embedded in the par-
enchyma. It seems probable that tins species feeds upon the rmin-
ute algal growths in the masses of filament where it habitually
lives or upon plant debris just pelow on the surface of t he mud.
=i Se Se
our
> Sligo;
ef tad?
. abot im Bat “Pee:
ened Paul obletee ett mo. affes seorpe dh
. eA ea a: (ioaetag. arf? To eon AK BEDS edt xa Oey
tOLOD
~~ ' a
; iL Iles
f te ©
‘ _ «= J Ei
r
~
beonborew ay £ ieee ina ,eetes? ,choalg aloy ae
Y fogs snoet apcome SLs Jarvis okvecton saat:
Liev sided 34 emertey JrempLZ¥ Yo Secsam ety tals fe won,
wut s¥lstep;lb off ., aarict node Ran
bseat) stem & nol ban shmefs Zome IK
te anilicupe. tects sonssels e wtid
|
be t ae
ef sears o8 sonsdadie soap te ee
ig A enon jon eb shesed thpee sq ai rota as Jeom Ta Boa séLugorl én ad
re
sveveo o8 saliaso® vena ag veo ag v: a Se
MOTs , LTE Steimo aorw 3Ieonegga | it d
oe |
: ee of) To meet ol¢elnetseranto ots Swen
mS
be _ -~ - ~ F ~ . Pes - SnsAne2ne pmol viieloegqee el pee
J18G0 18) pil iow reheets yuo ede
O2 images mi eton to Snler yino ents
SNS OF ax rely etd mow rts Has touS of
- Jin =
sn
se2 “beet ben egal ad Spe ond onertw eee
=a) EBS al ei, aa-nokensine doue to eles
on a
yea
sip
ct To sents et? to pobed sang aiuén, Sig
= be > i : i fi
mPa 1
145 [t presents a type of structural detail very different from most
other species.
Dalvellia siforma nov. spec.
Specimens of this specieswere found in abundant nunm- bers in a sand-bottom pond together with a half-dozen other rhabdo- oels. The habitat conditions were somewhat extraordinary, a fact yhich will account for the specialized structure of all the species. It was taken always from masses of Nitella and never from the bottan
or from any other plant tangles. In the aquaria, it very freely
‘swam out into the open places and was not one ofthe lurking type
but in the pond was never taken from open water. Possibly the rea-
gon for this was the presence of food in the algal masses of the
‘pond which would constantly attract.
Even to the naked eye, these specimens were surprisingly
different from the general type, and the distinguishing details are
all of a conspicuous nature. Never more than one millimeter in
length, the average was much less. The greatest width and depth
are at the middle and are both a little less than one-third the length. The shape is a rather uneven spindle. The anterior end is
very bluntly pointed, the two lateral margins making an angle of
55°. The tail end, however, tapers out to a slender rounded tip
which is almost always held slightly curved or bent to one side, so that altho the animal when moving follows its course constantly, the body is never quite straight. This habit was much more pro-
nounced in some specimens than in others. The portion between the
a ar —x/ 4 e ; : ae —_ ' 1ST TLS ysev. itateh Gems ae i : a ma" ak
‘ Hogs «VOR arch tet ah, i
x
ahranfo mf heitokh es 9 aed 2eu8 é6icy Xo 8 ae
:
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? oy a
; e\ VULIDSOHTSRSe Joven sew anolilbaoo Janae ~ he 9
‘ , A y
<eloeqge etd lie to esuzounse heshiaioega ed 3 10% See
LA = a. At it moat seven fre eliesif To sessan mott eye
ie 1ev 2i ,sittesupe edd ni ,seigae) daely Sen ; $
: . = HL OnE f Jon taw. Oe €e80sig nseae Srtd oe ‘a
= . H Mid i. c 1d ov? osz i - jon sa8 . to 85a [pe J i DHeot To sansest ort7
“<>
d JEF%USES OF8W BBeoege e-et? .@ye Satan ef? of no di : L :
listed yaidetvanigel £ ot) fina” ,eqgyt- ipaaney rte 7 2 n
~stomtitim ene M1 oom Teverw. .o*uMtean erouokgenm f
. rege Be dihiw 2eetvee, 6fT .eeol. fom taw ons7evel
wit Dviti-eno mad? eeel efs7il eutied ous fae e Libba & - s o tcineges off ,etintee cevenw seféen 8 al a
« i -
‘oc Signe ae prides bmby tM b doreaas ow J edz oe
He shemiiimenaie B oF. 260 e%eqes ,teveworl ora is
526 ee of jned “© Bewass yitdasio bLert woos
. iinetamoo esegeo atl ewollol paivou aeew Seat cp. erie" « “Ong Som dom tew tide eLAT -thadeave eiiupé
ems novwied moidwog eff erento ot mede ans
1?
PAE
146 ad and tail is quite thick and solid in contrast to the atten-
ted extremities. It is cylindrical for only a short distance as he sloping begins very gradually. The contraction is not as con- picuous as in many forms but is better developed in the tail re- gion than is common. The lack of a neck constriction and the shape P the whole anterior tip precludes much movement from side to side nd the body as a whole is fairly rigid and stiff. - The color is early white, opaque to the naked eye and not very transparent nder a lens. The only direct color, however, consists of a lat- ice work of heavy pigmented cells in the extreme anterior tip. Mese color cells are arranged in long, angular criss-crossed rods ghich are quite irregular. They make a maze of dark brown sticks surroundéng and obscuring the eyes.
Te integument is thin and transparent with well-devel- yped cilia used to a great extent in locomotion. The rhabdites are mall rods so clear that their concentration in parenchyma tracts is hardly distinguishable. The thickness is nearly uniform over the body except some little differentiation in the tail region which is used as a means of attachment.
The parenchyma is not heavy or gloselt meshed but is
more opaque. It forms the supporting cushion layer for the pigment
nass in the head, keeping the cells within their relative portd-
pr. pone i
y , Papi, ;
-neiien ef? of 7egsgnbs at Siice saa 7 & ’
pS.
sonasélb jxodte a Ying wt Iapbabaliyo @f
sre: pease
@ v > 4
‘ae =
| ~ioo ee ton et nokdoetines ot? .yiianhey eae
-oi Iles af? af Begeleveb veifed 82 Jud emtok ‘a
ey
sty
: . , yeté of? Dns nolrtolitenco soem 8 Ye wont ont ie oF S@bie tiewl Jncesvom Comm eohuloeig giz nel
si ‘toloo eff .Thive bos Ofai« Wieist 6: élodw ee
x 7 a INS laQeces Vey Jom bree eye besten odf 63 som
=26l 8 lo atelenta .fovewod’ .joics jonath ving P
Fas J
Gl7 “OTN INe Seeaske eds af elles OS JHGNa Ig
or beeso1s-e8sip Seloane anol mi esnetis 6068 Be wet
+) . a
SXOLTS Bwow as tO saem e otam vecl ralogoetad ee, . et
-20y9 oft painvosdé y as
3 ~lovoh=lfew niiip Iapiegensss bne mit? si jasceimeint Bee
seriidarta eff .nolsompodcl al ‘sneeke Ja6°'= B of oond sevyfoherag atl nolijevinsonos sfods Sard seek o : ovo oelion yiIssen ef esenmtolds att ‘efdartedin rei “ ‘ nelmet Lis: ods af nélestsmoastIrh efssit cece sal
ainentosise to antiem 2 as J ;
; igi ci ond badnex tieeers 3c yVaert SOn @f serioneteg 4 i:
nergigq oft set toynt meters eal doggy’ ste geret ce: oe { iat es aa
-,.%0q svisaeiet *lody nirlede ellen eds paigqeex — baod
bere) -
) <- . 6
147 Dalyellia alba nov. spec.
The habitat of this species presents conditions very
nearly like those of most ponds. A muddy bottom, with roily
dark water,some amount of leaves and other organic debris, much floating Cladophora make a surrounding environment suitable for Such rhabdocoel types. Chief among these is Stenostomum leucops. Ihe Dalyellias are always taken from masses of algae. They appear to find in such a situation both a good feeding ground and a safe urking place. In very many hauls a few specimens appeared but they were never in such numbers as Stenostomum and were never s0 poldly free-swimming. They were often seen, however, gliding out from mazes of filament and seemed to swim partly by ciliar action and partly by muscular contraction. They spend most of the time clinging or crawling among the algae but when removed to a watch glass or aquarium never seemed to creep over the surface as do othe species. That is, their methods of attachment were not develoned and the locomotion was entirely free.
The general appearance much resembles a short, heavy
Stenostomum. The length varies from 0.75 mm. to 1.0 mm. but seems
much less owing to the relative great width. The width is about one-fourth the total length except thruout the posterior third, which is narrowed as a tail portion. The depth varies at about the game rate as the width and is always very nearly the same for any given part. That is, the ventral surface is convex with no flat-
tening. The twisting and contraction are only slightly developed,
+9878 sVOR, OES
—
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fies Atiw wsegdod Vhoam A Sino, Tom tere
<2. "0b oinapio Gelso has seyvset to Seton
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a <goMmiel oumotaccet2 ef vaerd™ wuroaw Lend? .. teeysis 8 vot? .crgis To eSeedm mort neised auewle eae hon Decks, wabheet Seoy.« diog «sc iausie § fod Be ; ge wel s fuel yes yapy Z ¢ j i tf arr 32 f hae | PU aie one £DL 3 a : wor «t3* e i > OE pelt wv et ‘a ee
a ao Siiio vd yloneq whwe. ot Bemmse Bez InouuL id to
; eT 30m Dre yerT ROL TOBUINOS “Lee 1 OARACS yy : « HX OB FNC elioerim YW
i >
SY 6 OF DOVOME fodw Jod ey al? pio poiiwers
cei 2 eds *evo queto of Deane x 1% SByoOn sk
(oLoveb jon grew tnemilosdse To aedonsam sient ,e1 .69%9 edeibana tam GOlso
veer 4: PO e0ldewaes coum sonpaeyen Darien ont sy Sug tn O.l Of ,omE BT ooh uel Hagin £ scat el
3.85 @ipiw off Ey tap sibiden. acy of notwed
(a
lds woliesrqen ato septal IgeoKne dayarot Lussos “ng OOS JK @eitavy atgeh gat sor yxog ties & 62 benowa
ia Tol emer ont vised uey ayaels et bas atbkw ods" sa
“Jal on dole gerne, ef some: ierxdnev ats ae a
iz qolovel Viirigh te yao ots : moktoaxsn00 Dae’
a 148 ‘tho the body is not as rigid as many forms and the head is often
drawn in, the back humped up and the whole made into a nearly per-
fect sphere. Superficially, the color is an opaque-white, with a
Slight greenish tinge and is heavy enough to make the animals stand
out prominently. There seems to be no pigment whatever, even the
eyes are not brilliant or dark as in most of the genus. Both integument and parenchyma are somewhat clear. The
former is thin and regular in outline, allowing the scattered rhab-
Gites of the internal layer to show thru. The cilia are quite
definitely heavy and regular all over the surface except on the
tail, where they are about five times as large. The whole end- portion of the tail region is evenly clothed with these larger
cilia, making a specialized organ of locomotion. The layers of
tissue beneath the skin are masses at either end of the body, and
also form a thin envelope over the central body organs. This par- enchyma is very closely meshed with space for a very small amount o& fluid material, so that the appearance of both the head and tail is
as thick and dark as the middle part. This is somewhat unusual,
as the extremities are almost always nearly transparent. Another point to be considered is the fact that these two ends are of much greater relative size than is ordinarily the case. This seems the | result of the storage or concentration there of so much aiffer-
entiated tissue.
The central body mass is almost entirely composed of
. the digestive and reproductive organs, the latter during the re-
Ane sare? e8 hiaiet 88. OD otat ghar eLorw edi ¢ bas qu beer etal f a ‘ rc ae iw-ospeao #6 @l xoloo ert: vi tebotte ff ° , 4
fwone ywred, ad pan coi it
om od O2. eaeeR exedt \
ae ‘son-mt e8 Ausb to dnaksD
‘onesag Ds tnomyesat ate taloget Daa
Larrea
"aJis J@ adatam otn aise ert ey ods Lantago ei fseve agolevae aldgy y1eve , Le tats O88 aliem arfwemoe B81 eid? 23% elias ert #e #268D 3 yixeen eye: ¢eomlie eae saiz
yaattd sid t38% afc ef Serishienooy
4 * “.
.oeao One ‘ed banatt bo al meds vata vhs !
—
ae a 6
‘tif dom oe te event moftertneoncd = omsencity: ode
“i? neta vetfal ot? i ort rontetetil ae
149
roductive season occupying most of the space. The pharynx and
ntestine are typically simple. The mouth is ventral, lying just posterior to the eyes and opening into the heavily-walled pharynx which is cask-shaped but very narrow in front. The boundary of this rather muscular structure is sharply defined and reflects the ight to such an extent as to appear shiny. It is comparatively small and not more than one-sixth the body diameter. It opens directly into the intestine proper, which is thin-walled and dark. This extends back to the genital pore. During March and April, the intestine is more or less obscured by the large yolk glands which extend forward to the eyes. These are heavily lobed but when fully Geveloped become compact with a very thin dividing wall. Over- lapping the posterior third on each side, is the testis very finely eter but much lighter in color. The ovary is small, posterior a position and lies embedded in the parenchyma. The eggs are about one-fourth the body diameter in size, are thin-shelled and gray incolor. They pass the emnbryological stages in the uterus near the middle or a little to one side in close proximity to the genital pore which is very large. As a whole, the reproductive system is conspicuous.
The most noteworthy details of structure may be summare ized as; first, a broad head and tail region with a large amount of parenchyma tissue; and second, 4 small pharynx; third, large
yolk-glands.
brie srnuntg eff .sontia ef) To Seen eee a Fine my oe eit aise al ASwom od? ott biask a i *' ; 5) _ ; “ywwiy beliew-yiiveodt @et2 opns ey dae tore 1
J to y1ehinwod off jaowt ab vorre ytIev Jud tow Tiey Daa boaiteb ylainde er auusoudgs *
\ =e
v4 ‘vitenagnoo eal ¢1 .vsidd sgegge of e8 IRESES a
amege tI .toteonelh yvhod end déxia-sae ant? ese
= 1 : * . | , hin Hellewenins el doidw ,.eges ealveesnl ont: « Ge : — y at Mit ,iisgA Bas cdowall griaed «.esoq Ietinea ort od) MOR
yy efx lu A x Lo + on tal shal > va herxzoe 26 geal "0 S"1Omt [ - Liat seiw jog Bedell yiiveed exe esedtT .eexs' 62 oF
io Vv iisw Saibivih aids ysev a asviw zougmos
, , ay" - ag CISV¥. GLiguey She Bs , OODLE Coed ao Bitsy x0l hie , Teoq Lime é€i yievo off srnwleoo nt 18 tcefgii fom
epmo ofT .sreriosetseg eff’ ai bebhedsaw sell ere
ms hellete-nidd ei ,esla ai tetemelb ybod et) Ag
ot ylimixesg daclo ab shia ene of efisil 2 uc Blt
svitcibouges ort ,yeledw a eA oping yiev «i doidy a S AL A
»Avovolgenoa |
o
=Thorn/n Of Ve oR SEee: “Lo find eb vdinoweton tom oft
*
trons paiend a cdiiw molpned Lied fre bred a 4 te"
opt oaths ,kaywedg fle 4 ,Srovea bas couse
a - i ~ 2 j 4 * + eo ia 7"
Dalyellia megacephala nov. spec. The situation in which this species is found is of typical formation, the important details being a muddy bottom, small amount
f algae and a large animal community. The general appearance is
Striking, due especially to the relatively large eyes and pointed
head. The length is about 0.75 mm., the width 0.20 to 0.25 mm.
4d the depth somewhat varying but never more than the width. In shape, the animal very closely resembles many others of the same
general type. The anterior end is bluntly pointed and quite flat.
The middle region of the body is rounded out, is plump and much thicker than the rest. Then, the posterior end is slightly at- tenuated and more pointed than the head but cylindrical instead of
flat. There is really no color but to the naked eye the whiteness
ais opaque flecked with the black spots of eyes which are large
enough to be seen.
The integument is conspicuous, since its boundaries ‘are definite and clear cut. Here again the inner wall is heavy. The cilia are very short and fine,all of about the same size and
evenly distributed over the body. The rhabdites are not gathered
in special tracts but are scattered thruout the inner portions of the epithelial cells. The arrangement is quite lattice-Like in its irregularity, the small groups of straight rods lying at right angles to each other. The muscular system is heavier than in many forms,as
“much of the locomotion is effected by means of body contraction.
a as a
» DOKERY Se Meat 6 rat i
faa
ryt to 82 haset ef senile “ala: sone
Ps 1, ee olgoy yhiter s aniod aliersd Py: tbr |
ese
a=
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FOHLW oy Natt SOM Teaver $ uid oni ag Ji
=g ite @2. Ape roia6j)e0q of; aed? .7669 ode |
RP at. LAO Lay rive find Dasn Ooms its ‘3 Liaise <n, \ ‘oxen
he
tivtw edd ey tan ett of ied los on vitae ia ‘ ; ; is , . ;
i oie tiofrlw @eye Teo eteqe wont ocd’ ddiw Be
ie more OE FOLSCEa Mad al nomuge rat xf
.vvoert 6. Siew Sennl arts ALTERS Otel 200” i975 Ata : , =
as
suns erly yuede To iis ,onkt Sas tog ew tom ots eddtigartt eff ayhed efi-seve heya
eroicrog tenn gts Iwas Heist pace ea Jog S7Gme
; =a
verte
~wlitel etlvp 8) Snemennevis 6aT- .olies”
-
? ba
it te gatyl eben tdplavte to sequen Lipa ont 4
. bear.
RH SoMOT Youd nats vei vee el med aye. nels
+(OLPOaNT HOO Beg to anges xa hotostte ‘af 1 3
| lies, however, very near the integument, due partly to the
act that the parenchyma is not abundantly developed. The lack of arenchyma seems to be correlated with relatively large digestive
ystem, which nearly fills the body mass. The pharynx is very
ge and extends far forward leaving anterior to it only a small
triangular area. The wall of the pharynx is made up of two kinds
ofcells, regularly placed. Those lying longitudinally are very
slender and reach the whole length of the organ. Those extending
around are also narrow and thread-like, and together with the longitudinal cells make a cross-hatching in the interstices of which are large, broad cells acting as a framework. The whole is
very muscular and is turned and moved constantly. The position of
he mouth is noticeable. When closed, it is a very short slit at
the anterior ventral edge of the pharynx. When fully open, how-
ever, the posterior corner is drawn pack ventrally as far as the connection with the intestine making the whole pharynx bend downe-
ward. The opening itself is very large and conspicuous. The in-
testinal wall is rather heavy but otherwise the details of structure
are not strikingly different from other species of the family. The food is to some extent at least composed of the eggs of other
forms. In one specimen, eleven eggs of Typhloplana viridatum were
founr. It was possibly true that these all came from a single in-
dividual which had been bodily swallowed and the soft parts quickly
digested. The heavy muscularity and such food masses seem to in-
dicate a habit of voracious feeding.
‘ioe © yino Jk of tobwives galwesl biawiel Sake
Visa¢ ent. eonint. Pr
soi aff .dedeleyes Sritehenee Jou eh
i-6 syvel yleviteles diiw beseletion ets
view af xaytadg oT asa yhed eft eliites *
‘ is! ¢
ae
nix owt lo-qu eiem el xeeaarto edt te lien eat *.
a16 Vilanibntigand gniyl ssedT dovalg vie HesEG SRONT .neBno eft Toe final e forte ott?
Scit M2lw ws izvepos Hine ,.ovli-hessi? Bre vo stan ; —
16 660i seein. oft ni gaidosant-nect 2 eden O08 > = 7
‘Lortw aff ° .ivewenezt # es aniioe elles haouwd rus) a
ttieor srt » (Ati lano> Dovom tua ben? at Saas
; ' Z
, 7 ¢ : _ a" ene yisy Fel ti Sszotlo aetfW 6ldsesigge
‘dg ' ,feqo yiln? nedW .xinysedee erty 2, eghe laxwagy: L : -
nwstb ef teat. solide
. : 4 P afm wet i @a Vildasttney sored
isd amotq elorw eft pridam oniteadinl edgy Zz.
T .evouoigaenos bas oyial wey €i Teas arin
"4
'é&. 206 aligngeb ey selwredia 2m "veo, Ioriias él [inal oft te aesioede dente movt soeceltib vipa
to eae oft Jo _ Resngmos repel 39 snesKS 08
wiseheidy pry <nkusheiitt te auye Ke he (MOOT OSCE on | Aad
fuatea & pet? omee Ile seat? sed eiaz vicianog 4 P aiaey Tioe ad? Baw faweliove vA Bod aged het §
Ot mage feagam fog Roel bowe (snes eoeann
aeddeot eve. te
152 The reproductive system is extraordinarily far forward
th the single genital pore nearly at the middle of the body.
e two testes are long, slender organs opening by a complicated s-like apparatus into the receptaculum. The head portion of the ermatozoa is very large and is easily distinguished thru the wall > the vesicle. The ovary lies a little to one side of the middle carries about ten eggs which in the younger stages showed very y small irridiscent globules arranged in rows along the edges here the eggs touched each other. When the eg3s heave the ovary, hey pass down the short oviduct to the uterus where, one at a time, hey develop until they have a diameter one-fourth that of the
dy. At maturity, the egg is very conspicuous because of its leavy wall and solid yolk mass, showing thru even the thickest por-
ion of the body mass.
Altogether this species possesses rather notable in-
lividual characters.
)
ne me Lv me
at aie £5! Thhone aes
bod ont? %e ontnibiek eds ia s wh tweet, ono “im
ee <4 Sqm 2 Ud. atiiago ‘as on: nedne le 200k oe
ara er
re a c
ols Og rest “eet np Liomiggtan ortd osiat
law e:f) sags bose hoget dat vilene ad ine drat my
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>: £2 op arte rye TT tind —s 3 a yi € on : € Lit -W re ft en? Ou Ps isHlr vo 2 Mt fa Ea) ona
ft if Bri’: PIO. -SHoO. ta a Ld 2 Oven v p j - ‘ q " is se : Si Tt ISHMNOSG oepevos.cemoz "SY #82 At art? is a2 4 2 Ach Ts
: co ’ raxgtd? ei" rave srs? : a nr psy ] ij | Jeoxold?) ei. nove Y? answote ase Hho bilee 28am a0 ‘s mari S190. OO TOs &@88eeceog solooge aid? ofc tenog te » £'18d 98
& ce
; ae ? Died i
sue Mg
= Sees . ~ 2 = a 2 ae as ; FE prec oe es r 2 . ey
ry)
153
CONCLUSION
Of the sixteen families which make up the Rhabdocoela,
epresentatives of five have been found in the United States. Up
the present time, about eighty species have been identified from he eastern states but only sixteen from the central region. To
his list of sixteen, can be added eight new species and different
ocalities for twelve others. From the collections just made, it
ppears that a great many forms found along the seacoast and in the order regions are also present far inland. The biologic conditions
in the lakes and streams of the Mississippi Valley are not vastly
ifferent from those of the ponds and rivers of the eastern slope
ad very evidently the same species are to be looked for in both egions. When, however, such a form as Microstomum sensitivum,
hich is present in the brackish water of the open shore in Mass-
achusetts appears again in the small ponds of New York and then is
a
found in isolated puddles in Illinois, some note must be taken of
its power of adaptability and some consideration must be given to the fact that a species so fragile and delicate may flourish in
situations far removed from each other and ofv ery different con-
'@ition. Other examples of a like nature are many, and it seems not too presumptuous to conslude that while few North American species
will be the same as those of Europe, the forms in the United States
not separated by more than a few thousand miles will be the identi-
cal.
Another point of importance in connection with the dis-
MOTORS i? <7 - =
ivovohd ath @ett gy sean cfs cet | sett
.c-9agG Aetan eay ct Hnwyort pee Swind, vitae | 4
7 | Rorbtenehk deed svnd weloeqe Yidgle Incdae,
T telpbt Lavsne > edd: Owe nopyxis yltte vod"
~r
—
b
TST TON Ane estooge wer ofyte bebbe ed HBB)
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ribution is the amount of variation found in individuals of the same species but living under different habitat conditions. This was noted long ago, in the difference in average size among speci- mens of Mesostoma ehrenbergii from Europe and from the United States and in the differences in both size and shape of Rhyncho-
rostratum from the two countries. There are, too, many minor variations among individuals evidently of the same species. This possibility of change is apparent in nearly every one of the old species found for the first time in the central localities. These variations are not of either histological or of gross anatom-= ical structure but are rather in the relative and comparative de- velopment of the several body organs. For example, the eyes may pe larger or smaller or different in position in specimens from one pond than in those from another. Prorhynchus applanatus and
Typhloplana viridatum are other striking instances of minor changes.
The specimens of the former from Urbana show a very much shorter
posterior portion with a more rounded tail than is given in the original description; also the intestinal diverticula are not regular and straight but pointed and curved. In T. viridatum, the differences are very marked. The shape of the head region instead of being pointed is nearly as broad as any part of the body. Then, the green color is diffused thruout t he parenchyma fluid and not held in the color bodies alone. These examples are sufficient to show the kind of variations common among the forms of the inland
ponds.
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geems to be almost cosmopolitan and more than any other is found in small ponds. Others, such as the genera of t he Microstomidae possessing a simple anatomy are also common. It seems evident that the more primitive types easily adapt t hemselves to unlike surround
ings and also that they are not so responsive to environment in
the way of variation. On the other hand, several members of the
Typhloplanidae occur in many places. They show a greater degree of anatomical change and are thus able to exist under diverse condi- tions. The two genera of the Prorhynchidae which have appeared here were found only at one place and then only as a few specimens. The Dalyells are another family not so widely scattered. S$” far,
they have appeared in only two or three places. The question of distribution is partially one of chance and partially one of ad- aptability. The above mentions only the general localities where the several families are found and the most prominent reason for this occurrence.
Any study of a number of families will reveal certain characters of comparative interest. Perhaps the most conspicuous detail of structure in such a study of the Rhabdocoela is the shape which is at once significant and important. Within the group there is a striking similarity of form even among types differing essentially in anatomical particulars. Never long and
cylindrical like the annelid worms, never very flat lik e the near
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related Polyclads, these worms are intermediate between the two.
Some species are almost perfect spindle shape, large in the middle and tapering evenly toward either end, others are very nearly gigar-shaped, the head being broadened and slightly truncate. The
most common variations are in the two extremities. The head may
be broad or pointed, rounded or sharply angled. The posterior end often tapers very gradually making a longs lender tail and often is broadened to form a heavy square spatula. Generally the anterior end is somewhat flat and the tail more or less cylindri- cal. Almost always the dorsal surface thru the center is elevated, Be enspe is eaSily explained. Most of the group swim out free thru the water or wriggle their way thru dense masses of filament~ cus algae and a spindle-shaped body is most easily propelled under such condition. The flatness of some species such as the Pro- rhynchidae is clearly the best shape for those types which habit- ually creep over smooth surfaces, as fer instance the stems and leaves of aquatic plants. Here they can cling closely without presenting a projecting mass by which they might be easily diskod=
ged. Then, too, the squarely truncated head will not cause any
special inconvenience, as it might in free-swimming forms. Another
point which may have to do with the shape is the entire lack of locomotor organs or projecting parts of any sort, and since the body is moved partly by muscular contraction and partly by the action of the cilia, extreme smoothness is a great advantage. AS
a whole, the shape is characteristic of the group and is closely
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157
related to the mode of life.
The method of locomotion has been mentioned as being
1y means of cilia and by muscular action and the relative amount development of either depends upon the functioning of the other. nere are four types of locomotion; first, free swimming movement where there is no twisting or turning of the body; second, free Swimming where the whole body rolls spirally; third, a creeping or crawling over surfaces in which instances the movement may be
entirely a gliding or slipping,
or may be by muscular contraction;
fourth, a scrambling or wriggling thru masses of silt or debris.
In the first type of movement, the cilia are large and evenly dis-
tributed over the whole body and the muscular system is used only
for special contraction. Strongylostoma rosacewa is an example of
this sort. The second method,of rolling overand over, is illustr-
ated by the habit of the Stenostomum, where the spiral twisting is
very marked. Again in such forms as habitually creep or crawl, the cilia are generally extremely fine while the muscular contraction
of the body as a whole is well developed and is constantly used.
Examples of this sort are Macrostomum album and the several gen-
era of the Prorhynchidae which always cling to some surface and do
not let go, so that they never swim out unprotected into the water. The different species of Mesostoma also have this same habit. These forms may be said to be lurking animals or bottom iinhabit-
ants, never found in open water. UPon occasion, when hunting ina
mass of algae, any form will make use of both muscular system and
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158 rface cilia in climbing around and thru tangles of filament, but
nerally where the activity is muscular the cilia are very small. nis correlation of cilia size with muscular development is a otable one in all the rhabdocoel families. Other characters of comparative importance are the lative thickness of integument, heavy eye pigment and extremely
It is perhaps sufficient to
jpecialized pharyngeal apparatus.
ention these details, since, as a whole, the members of this
group are of especial importance in elucidating many problems of
general biologic and phylogenetic significance. The following
utline summarizes the most conspicuous points in this study.
SUMMARY
1. In swiftly flowing streams where there is a rocky bed to furnish sheltered place of attachment, planarians and a few creeping
rhabdocoels find a suitable location.
2. For most of the free-swimming species, ponds and t emporary pud-
dles supply the best c onditions. Such a situation comprises,
first, a protected retreat and also a feeding ground which may
pe found in a mass of filamentous algae, second, a source of food
which may be found among the animal communities.
3. The response to the presence or absence of oxygen and carbon
dioxide is more precise than that caused by any other stimulus.
4. The reaction to light varies in different species but in most
instances is negative tho not definitely so.
0
th Re voy eve sklto end cntucelan ark cstelied &
ols ate Sooty sogat evi ses LO angst Sa fomengeo bas snougiq eye yveed. ,jnomumedak to
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witwollot of? ,eomsoiiinale oftenepelutiq Boe ae
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ae) Gulf
: : rn Mere x : Ha ed. nomltt To telgaay suit Bas yy
en ayy
& ei tasmoaleyed wialvoeum Ativ enka atlin, te
-collinst feopotdads elds
a
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a
L - OR a +YO0d 8 2idt at @talog suctoigenos teom edd |
CRAMAUE -
niqoe sd wot «2 fins eneisenely” .jnetuioasiea to | sfolsiasol eldstine. Be . i "toges® 3 bisa ehaog ,seloeda orlowd we-eert ets * di o yous TS MOO” AOL sulle # Move. .enobs thao o seed oda
i Jeom mi Jud eabsoges lal He aviney Sold 6859 a
Jeo Ine negyne to SONAOTS 0 sompaesg ‘ong Os
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i‘.
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joe visghatten om oct, evbe ei
- a es , ; S lay W
159 Response to temperature is to a general or diffuse rather than a
ocalized stimulus, as for example in the seasonal change in the ondition of water. Since nourishment is gained mostly from disintegrating protoplagn
he food relationships are very simple and altho nearly defense-
ess, there seem to be few enemies.
). Strongylostoma rosaceum differs from other members of the genus i
possessing large testes. The embryological stages cover a period
of nine days.
8. Planaria maculata minor is a form in many respects resembling
maculata but differing in development of eyes. It is a type found only in the Mississippi river or very near it. 9. Stenostomum giganteum, a large species with a blunt anterior end,
is found in a single pond. The mouth is not as far anterior as in
most forms. 10. Stenostomum glandifera is slender and possesses many small
elands in the wall of the intestine.
11. Macrostomum album, a very transparent form, is found creeping
over bottom surfaces.
12. Mesostoma simplex has a very transparent parenchyma and simple
reproductive apparatus.
13. Dalyellia alba ia a form small and light in color.
14. Dalyellia fusiforma possesses 4 conspicuous mass of pigmented
cells in the anterior tip of the head.
lyellia megacephala has a large muscular pharynx and eyes ple-
ett sorte sertTEs a Lateonekod & a aunds
fen
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ri Rump ots To e1sdsem worizo sont i telat!
—
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BIBLIOGRAPHY
all, Stanley Cc. 1916. The Development of Paravortex gemellipara (Graffilla gemell- ipara Linton). Jour. Morph. : .
whild, Cc. M.
1901. Fission and Regulation in Stenostomun Boston, 2:329-31.
1902. An Experimental Study of Regulation in Stenostoma. (Amer.
| Morph. Soc.) Science, n.8., 15:527=8.
1902. Studies on Regulation I Fission and Regulation in Steno-
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leucops. Biol. Bull.
~
leming, J. 1822. The Philosophy of Zoology. Edinburgh, 2:604-5.
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1886. Die Turbellarien, Rhabdocoelida. Graz: 2 and Plates.
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Kepner, Wa. A., and W. H. Taliaferro.
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Leidy, J.
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1852. Corrections and Additions to former Papers on Helminthology. Proc. Acad. Nat. Sci. Phila., 5:288-9.
Lille, F. R. 1901. A Comparison of Power of Regeneration in THree Genera of
a
vw iii i oe : ‘es | 1 « fe. j , i” * wir!) ee We
Lioron si ist an) atte del Lemes, xo novennt 19 2
ian > ad i - =<
. ; ~ fig] room Paexirey . (nod
lfof .:fOfK .egngiret menipreogete ih AO ey Aree & \ »L&=PES eee <a 03
1omA) .sooteomrt ol woltinignedl To veause lpsng
. ‘ aS Bde? | oO, SOM Sloe 58a ate opps ai coisjolugel thee golnert 1 molsalouek eee
pe
® & (Oe rh och -Talrel sos . Wiese »Boee ae SOF i to Loxined Ie aga IL oLsalagen no Bek: owt stots .terdgeonsve to ea: ofT frig abi ool i ng Fi
_ ig S ,¥e+b00 485 sae Bioeeh Jo anstovagaed yiotelugen 111 noiveisgeh AG ee wioeW | ~ADTA . hun ones mi ehioo® toe site . . »foy © ;OReg s9L if
* Ory) ne
SPOS so pttaloR .vaoloo® Lo: yieoeod
-2e0e/2 bee & t2a80D .,ehileoooidadi «fie ine l Tete TV €0°L anew .e390iF how netlesiei els rélcaliodag tat & bro .olt sxoT £ sien a
*BSqows, meyend seh Heo goveosw weiss l led) ole » #80:083,lcoR , eet. tee
sme neginietevy aoh sleooolilA Des aleoovohdenh aa ‘90 eOll=L:f6 .foo8 .eulw .tie® Vemitsemab
[iexiuet) ei teorabs ‘pergeviort sworif Be nkapdd stat 6 tae VRed isd oe pearteht (tay ugnev ves Sev
sonnetetia? JE .W bas "i a to: good (cee echt serewiied amulaatad no tnoqek wig smd. (. fo@8 .508 isaerale 3 Sreaatenhyas NiterT bum eleoooke
ae a M4 ie el COOL
erRlint shoe nem wBSOA sort seater lat oe “ino ti
te peneD ag silt rh pokseran er,
a
161
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a i
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Schmidt, 0. 1848. Die rhapdocoelen Strudelwurmer des sussen Wassers. Jena
' 1848, 8°, 65 pag.
Sekera, E. 1888. Prispevky ku znamostem 0 turbellaruch sladkovoduich. Sitz.-Ber. d. k. vohm Ges. 4. wissensch. Math.-Naturw.
Cl., Jahrg. 13888, S. 344.
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Zeit. wiss. Zool. 41:48-78.
Stringer, Caroline E. 1909. Notes on Nebraska Turbellaria with Descriptions of two new
Species. Zool. Anz. 343257-2626
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= “= LG : 2 ' WZ oh = a Wel rs . (ond SS B= © samsiog tb Mt o¢ eon ; sC1L-8Gi04 ,onerancal® Be 2. ilaioeg® fav yrorlitodvent? cevtselivamteave sente! Bae ind To oslo (Tue *teerawide <a “es ytd | e-wisa ee : “a “iE ri ,Teperimqol ,tfeiuuamen neqaudose ses . too wee iar Si 4 Lijal 2 tmmodd ; R¢ A etpoiiiones, alliitss) to sasmoleyes ’ “EV ESSS LOH abooW «lind ,ioif. .ynovwney ise Ya 4 f {San neterk #0) aero bobo? "pel ococtokiaian re Ce Pas bot £ <dHolupovotieLe ew! Lewd o seveonens on yoveqek e i~ «fi J aM VIE NSGALW 2B o fe fein’ | me amele-gxng IB. oe er sPRG 28 {8081 sade i.f0 iis Ae fr. " peat lionsiiok mpbiwdledar? «eae Samant oLh “edn negansioe . TBR SE ioc abale ot ttee wort ows to anoliq) spaed eiw abtelledaet. cern f
a cee
eaten a sot. x ey
SOS-TCRE wsih too ,eeloe,
152
ianin, W. 1870. Die Turbellarien der Bucht von Sebastopol. Berichte des Vereins 4. Freunde 4d. Naturwissenschaften zu Moskau, 1870, 4°, 96 pag. und 7 Tafeln.
ejdovsky, F.
1882. Tierreische Organismen der Brunnengewasser von Prag. Prag 1882, s. 54.
1895. Zur Vergl. Anatomie der Turbellarien. Zeit. wiss. Zool. 60:155-8, Tab. VII, fig. 95-102.
Nalton, L. B. 1912, The Land Planariana of North America, with a Note on a New Species. (Amer. Soc. Zool.) Science, n.8., 35:940.
Wilhelmi, J. 1908. On the North American Triclads. Biol. Bull. 15:1-6.
Woodworth, W. McM. 1397. On Some Turbellaria from Illinois. Bull. Mus. Comp. Zool. Harvard College, vol. 31, no. 1, 1-15. 1896. On the Identity of Procotyla fluviatilis Leidy and Dendro- coelum lacteym Oersted. Am. Nat. 30:1048-9.
Young, R. T. 1912. The Epithelium of Yurbellaria. Jour. Morphol. 23:255-68.
hacharias, Otto 1902. Eine neue Turbellarienspecies. (Stenostomum turgidum) Zool. Anz. Bd. 26:41-2.
to A 74 (oJ AA , Lowmodeigde? oon telouet “ob ut 218. tbs y” eiMttoew of nel ladoenerdiwicsal ib ohauent sh be 1 selo2nT T Daw Beg og
O87 nov Ue M~OQem NT. Hod aes
-loo8 .pelw .clet .nePyol iegant Seb eimeseaee 3 .80L-08 uBit ,JIV Cat B= 1
6 it So o dsiw ,settenA dis Yo anebeanele sOOC TOE .et.e ,OOnatoe (, feo .co® .aemA) ae
O~L;02 ,iint toll .ehaloie? nabidemd RET st § i |
’ an 1hOGe »{yewd » SEM aa ire aBie miiii fac “<7 bial Levit 7 fof (f son J&sfov ,epellcd taava Pay “oN paag Pry whi od Oliiseives? afyjooo* xt to wilraebt . e@-OPOL 06 .ta 1m besuse0 sue dnad. re lege | Te } HO-COELAS alorigiom awrol .stipliedagyY Jo mriledas ‘4 ‘< ;
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List of Abbreviations
= brain pi = zoochlorellae
of = body fold rh = rhabdites
> = cilia yr sem = receptaculum seminalis tom = commissure s cell = sensory cell
tp = ciliated pit 39 = eperm cell
38 = cirrus sac t = testis
syt = cytoplasm u = uterus
_ @ Sye vit = yolk glands
sp = epithelium vs = ventral durface
a = flame cell wv 3 protonephridium
gp = genital pore
int = intestine
int con = intestinal constriction int gl = intestinal glands
int pr = intestinal prolongation lef = light refracting organ
m = mouth
nucleus
u
Oo = ovary p = pigment par = parenchyma
ph = pharynx
EE _
ee i ee
—
re ee =
, | _ 4s |] Vee
—- a
i iin a ae
’ as
seileroiiooc: & ka wy A gellicady « 1% tilanives roloondqgemed © men 4 ns "
ifes VO8 NE = Ile 8
iLO rise ¥ qe ae ah
elsnng &.3
ehiaty, aloy > IL¥ eosliiwsh Laitcey © ey
~ Ml biwigqeroicsg © yw
ee anolsalvex
Ciete © s
a Pat
neisostanon lanite
: i) Rbriedy leniss. oe |
nelisyoofesg lant sesig
-_
eae aks oeitet gi
Explanation of Plate I x about 150
Fig. 1. Strongylostoma rosaceum nov. Spec. Dorsal view,
rosaceum nov. spec. Lateral view, x about 15¢
Fig. 2. Strongylostoma
tf etal to nol taralgx®
» cs tuode x ,walv Letuod .Sege .von gyspasoy am
‘Wol suode x .weiv [Axetad .ceye » von amaorent G10 3 BO
> opt
Fig.
Fig. Fig. Fig. Fig. Fig.
Fig.
Explanation of Plate II
Cyclops shell with Strongylostoma rosaceum feeding within, x about 15.
Ovary of S. rosaceum, camera lucida, X 100.
Testes of S. rosaceum, X about 100.
Rhabdites lying free, camera lucida, X 100.
Diagram of S. rosaceurm extended, X about 90.
Diagram of 5S. rosaceua contracted, X about 90.
ee te ae
Gell with rhabdites, camera lucida, X 100.
TX ogalt to noitansiqua ; a
tinilw gtibest qyposto7t aposeotyanowge diiw Lieds tL 2
{ 4
.0OL X ,sbioul sisieo .weogsoy 8 Dae
sO0L tuoda X jeepseot .8 to 8 a 00OL % ,ebioul avemo ,oo7t gabyl eegERgl
00 fwod s % Pebnet#e agecaecoy 8 tos O08 Joode X ,besonitnoeo supeoasot 42 Jo
;
|
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)
_ ine, hee Sa kn ee ee an TL ie
sp
(Es + oe —3h Ji,
PLATE IL
a LIS > Sy Pee, a= ag men Tay ce eri ga : IO oOo SS Ly
ITT etalT to norrematgaat Il ebioot svemeo atiw swath etew GE<E a fi rypcPaon smoseademingns® Lo e350 8
| (eopate
00L X ,sgeze Lie0-9no,
,004 xX ,ogese {loo- -
1001 X ,ogeta Lloc-owauaael
,00L X ,otaiqamo ylxson |
001 X ab TeIi2 sag Ae
eOOL ZX satrwy isc sse00ng mr -,M.A oc:0. ah ,OOL X Moat batatos ot, A 80: OL g
a00L K ,heblot doum ,yad din
.00L KX ,Welv [serch ,veh, ae
,00L X rely Siesee) ‘Nab ote
5001 X ,Lleda ¥tqme ‘inh dak
-Ch Joga K ,bossergaoe pieatis' MHS LS | |
«OS t tnode x ‘Seeitenampe:s vtingite agabiadyg ,OP tuodn & .Poaeergnne eheBLLe Adeigeocanom alls
02 dupa ke eo vLsrtigite ines
Oe . i } i i - 7 U . ® / — a Se ae 2 Tien “Se 5 : Mt Eee Se & = 7 ’ \ 7 Peer) St ere *
— = —, ssl ae i ea ia aa Fe eae Pe “yt er a ee ee 7 | a ae el a ee
. ; A t: = on SY . % tos ; 7 ow) ~ ~ = j = 4 3 4 vf Z “ae” “a ' 5 ri | i‘ 2 t
PLATE 12
EA
Of
- rape te ona
i< sy P . pao
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; , a4 et
nada yh eaeate a: i tacwmaey
%, oa i764 198 Ov
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ena ae
PLATE 111
35.
36.
37.
38.
396
40.
Explanation of Plate IV
Reproductive organs of Dalyellia alba, x about 200.
Protonephridium of Dalyellia alba, X about 360.
Rhabdites of Typhloplana viridata, one in cell. Camera lucida, X 350.
Eye of Dalyellia alba, X about 200.
Tail region of Mesostoma ehrenbergii, X about 100.
Rhabaites of Typhloplana viridata. Camera lucida, X 550.
Rhabdites of T. viridata, ola cell, X about 350.
See 8
Tail region, Mesostoma simplex, X about 100.
Rhabdites in cell, Mesostoma alpa. Camera lucida, X 150.
Vitelline gland cell, showing stored oil globules, X about 250.
Ovary of Mesostoma alba, X about 350.
Girrus sac, Mesostoma alpa, X about 350.
a —
Testis, Mesostoma alba, X about 350.
Rhabdites in cell, Mesostoma alba, X about 200.
| ll ee
Eye, Dalvellia alpa, X about 175.
¢
End view of rhandite-bearing cell of Mesostoma alba, x about 350.
VI ogas9. to noktans!
1005 suode * agin abiiovlell to enegio ewitem
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rien) .Lipo al ono Sstebisiv angiqnituy? to e6e5 “ | | 08 % abo
008 suote X wie aLiieviet ton
sOOL Jnoda X ,iigiodnesde smpseoasl Yo molded
’
i fo
a s0C8, KR ,cshiowl sueamaD setablaty susige titans To #9d Diath rf
-068 ¢vods K ,fleo hio ,stabiniy .T to ses tie . COL tuoge X ,xalgmte quotkoesM ,xoiges 7 ;
OCL X ,sbionl svemed .sgle smozsoaek lies al orkid Le
X ,aslvdol>y Ibo Bewse antwore .Iflas boats ontilers, L 4 ~_ S c 3 | »OGS s00g#
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308t suods x edie aro t 2ceghl one BOF
O88 Syeda X ,adle Ayoseonght \etee
008 sues X jacks agosecast hkeo Mt apdibdall .08L tuoda K ,ile akileviad evi
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a
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PLATE IV
7
Explanation of Plate V
41. Mesostoma ehrenbergii, lateral view,slightly compressed, x 50.
42. Mesostoma simplex, slightly compressed, X 40.
43. Eyes of Planaria maculata, X about 100%
44, Eyes of Planaria maculata minor, camera lucida, X 100.
iss Se 9
45. Uterus of Mesostoma ehrenbergii, showing young worms and eggs just ready to hatch, X about 350.
46. Section thru fission plane of Stenostomum giganteun. Camera lucida, X 150.
¥ sial? to solsenbiqna
. (ti keke TOD “i Tal le ewer issasisal esa ogie 388. Puy
0 % ,beteetqgmoo yitdatie ,xelomte soe
: ; a 7 A } #O0L Saode K gpleoay gineceld “Term
Of X ,sbiool avemed. ,nonte ajelpoom gisenas’ Soe | ; ; a ) es. aA erriow sruroy petwore PP oho Fate al) peo 3508 SM to ’ é , ‘O68 JIvode K wiodsat of yhaen Jeng ie,
‘wet heels pemovyeonaye To orala noleslit gadd tod a ae aa toe PETeY FONSI G .
4
" 306L X ,ebioul sz
Sy eee ete
i im i ae ae pe om
As; = rd te - , t oak LJ 43. | > SO hd DPR they ee aa SR pit es aia a + ibe We oaE
ae iv . ; ju atin bf ia Big esd
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be
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PLATE V
|
Ee a
+ } 1 >
J
SE _
Explanation of Plate VI
Stenostomum glandifera nov. spec. dorsal view, slightly compressed, X about 120. lateral Stenostomum giganteum nov. spec. dorvsat view, slightly
compressed, X 100.
Head of Dalyellia dodgei, antero-dorsal view, showing elevated mouth. X about 100.
Head of Stenostomum leucops, pharynx closed, X about 100. Head of Stenostomum leucops, pharynx open, X about 100, Nematocyst of Microstomum caudatum, X about 850.
Lateral view of head of Microstomum caudatum, X about 100.
A Se
Dalyellia fusiforma, dorsal view, slightly compressed,
es
X about 90.
Transverse section, Mesostoma ehrenbergii, showing folds of body wall. Camera lucida, X 250.
Ventral view of head of Microstomum caudatum, X about 100.
aaa a=
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a ‘Lidpite .weiv [serob .coqs .von padi Sneig geo OSS twotds & bores
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2 : i ) 4 nei Aw? Livy tert EBS Dyes “eye Leone se : z 06S tieda X ego xmuata .eGoonel grepseone se 20 |
; O88 Ivoda K ,wortehuss sempsactoIM To tavenl oi to Soed to petty Laue SGeeu moo yitdaiie ,welv Inanod epeoliagt #1
x a ~ S ‘ ee ee 2Ce Inoda 2058 KR ,ebiond exemed..iiew ybod Tam
] A : ‘ : PS
; 63 EN a Ba vwoda ai e gt: pies 7 Ait a a g08 OM gFOa inee ee Tevaer$ i | s0OL sumis KX .tuiseboso apmpleoiptM to Set to wety Lease
a
a}
0
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oe
gg
456.
oa a ELMER: it Rp a
=,
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PLATE Vi
Stet Y se
POA PL ef
- eG . A GRC
Oe Ly SE PAM = Mo
A
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ae
i 44 5 a Oe
BF
Ty a y,
-
2 > te Oe ao ene ae ae 7
VITA 1885 Born, Syracuse, New York 1900 Entered high school, Muscatine, Iowa 1904 Graduated from high school 1905 Entered Grinnell Gollege 1909 Gr aduated from Grinnell College, A.8. degree
~-
1909-12 Instructor in Biology, Blackburn College, Carlinville, Illinois 1910-11 Attended during summer sessions Brooklyn Institute Labor- atory, Cold Spring Harbor, Long Island 1912-13 Instructor in Botany and Zoology, Grinnell College 1913 Attended summer session at Lakeside Laboratory, Okoboji, Iowa 1913-15 Instructor in Zoology, Grinnell College
1914 Attended summer session, Bermuda Biological Station
1915-17 Fellow in Zoology, University of Illinois
A
UNIVERSITY OF ILLINOIS-URBANA
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156