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QUARTERLY JOURNAL

OF

MICROSCOPICAL SCIENCE,

EDITED BY

EDWIN LANKESTER, M.D., F.R.S., F.L.S.,
AND

GEORGE BUSK, F.R.C.S.E., F.R.S., Ssc. L.S.

VOLUME VIII.

With Allustrations on Wood and Stone.

LONDON:

JOHN CHURCHILL, NEW BURLINGTON STREET.
> 1860.

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ORIGINAL COMMUNICATIONS.

On the Srrucrure and Move of Formation of Starcu
Granutes, according to the Principte of “ MorLecuLar
CoaLEscEeNce.” By Georce Rainey, M.R.C.S., Lecturer
on Microscopical Anatomy at St. Thomas’s Hospital.

Starcu, from its physiological importance, remarkable
structural peculiarities, and general diffusion through the
vegetable kingdom, has been a favourite subject of investiga-
tion with physiologists and microscopists. However, not-
withstanding the attention which has been devoted to its
structure and development, it is acknowledged by the greatest
physiologists to be known but little of. (See Mr. Busk’s
paper on “ Starch Granules,” in the number of the ‘ Quar-
terly Journal of Microscopical Science’ for April, 1853.)
There are, doubtless, intrinsic difficulties attending the inves-
tigation of this substance, but these have been very much
augmented by the principle on which the examination has
been conducted, namely, the cellular hypothesis. If this
hypothesis had been in itself correct, and admissible as a
basis of explanation of the facts connected with the structure
and mode of formation of the starch granule, it ought, con-
sidering the amount of talent and ingenuity which have been
employed in its application to these inquiries, to have thrown
more light upon these much disputed, and as yet entirely
unsettled questions.

After this apology for thus differmg from the high and
almost universally credited authorities of the present day, I
shall proceed to explain on a new principle—one strictly me-
chanical in its immediate operation—‘“ the principle of mole-
cular coalescence,’’—those points connected with the structure
and development of starch granules, by which physiologists
and botanists have been so long puzzled. In this paper the
same train of reasoning will be employed, and the same
experimental data adduced, as in my last paper, that on the
“Structure and Mode of Formation of the Dental Tissues,’
as also in that on “ Shell Structures ;” and hence, though
treating of a very different class of organized structures, this
is still but an extension of my former researches.

VOL. VIII. B

2 RAINEY, ON STARCH GRANULES.

It may at first appear startling that substances so dissimilar
as carbonate of lime, as found in shells, or a mixture of car-
bonate and phosphate of lime, as it occurs in bone or dentine,
should have anything in common either in their structure or
in the manner in which they are formed; but I may remark
that none of these structures is so simple, and so exclusively
mineral or organic as is generally supposed. The carbonates
and phosphates of a rounded form are all compounds of a
viscid substance and ea:thy matter; and starch granules
have diffused through their structure a small quantity of
earthy matter. I have always found that starch burnt to ash
on platinum leaves a residue of lime; but desirous to have
more precise knowledge upon this point, I availed myself of
the advantage of the assistance of Dr. Moldenhauer, the
chemical assistant at St. Thomas’s Hospital, i making for
me a quantitative analysis of some potato-starch prepared
for the purpose. The result of which is, in 100 grains of
dry potato-starch—

Dry starch . 5 . 80°80
Water : c . 18°94
Ashes - ; d 26

100:00

These ashes we found to contain silica and phosphate of
lime ; the proportions I did not think it necessary to have
determined. However, the globular form of the carbonate
of lime, occurring in the deep layer of the shells of Crusta-
ceans, is as high in the physiological scale as the granules of
starch.

In treating this subject I shall first consider the different
forms in which the particles of starch occur, and their re-
semblance to corresponding forms of certain solid bodies,
undoubtedly produced by the coalescence of their particles ;
and then I shall show that the chemical and mechanical
conditions necessary to produce such forms of starch exist in
the vegetable organization. The various forms of starch
must be examined both when the starch is in the starch-
eells and after it has been removed from them. Sections of
growing vegetables in which starch is formed in large quan-
tities, as in the very young tubers of potatoes, will serve for
this purpose. In such sections, in this and the majority of
plants, the starch-cells in the vicinity of the ramifications of
the vessels will be seen to contain very small spherules of
starch, many of them too minute to be accurately measured ;
yet, notwithstanding their minuteness, their figure is well
defined, and they are made black or blue by iodine, proving

RAINEY, ON STARCH GRANULES. 3

that they are as much starch as the larger globules, and
differing from them in nothing but size. These sphe-
rules may either be free in their starch-cells, or conglo-
merated and joined together in pairs or threes, producing
dumb-bell or somewhat triangular forms. Sometimes they
are found with shreds of membrane, and at others are
invested more or less by an utricle. In the starch-cells more
remote, the granules are larger and fewer, so that their
increase in size is attended with a diminution in number,
showing most clearly that the largest are the product of the
union of those of an inferior size. Indeed, the number of
granules of a small size is such in some of the starch cells
that it would be impossible that they all could become
developed into large granules without the spaces containing
them undergoing a most inordinate increase in size, which is
not the fact ; the spaces in which the middle-sized granules
are lodged being about the same size as those containing the
largest granules. But the chief evidence in support of this con-
clusion must be obtained from the microscopic examination
of all the various forms of starch, beginning with that which
is merely granular, and going up to that which is most per-
fect. Such an examination will show that there are exactly
the same class of appearances to be found in starch, indicative
of coalescence of its particles, as are presented by the several
forms of carbonate of lime, whether prepared artificially or
occurring in organized tissues.

Plate I contains representations of different forms of
starch ; fig. 1 is the ordinary form of the larger granules.
This was taken from the immature fruit of the potato.
Nothing that I have examined shows the laminated character
of starch granules so well as these potato apples, as they are
called. Figs. 2 and 3, drawn from specimens of common
potato starch, are similar to those pointed out by Mr. E. J.
Quekett as the result of cell multiplication by division, a
view still, I believe, generally entertained by botanists. This
hypothesis is considered by physiologists to apply only to
even numbers, but fig. 4, and also fig. 5, which latter is copied
from Criiger’s plate in the ‘ Journ. of Micros. Science,’ for
April, 1854, show three granules similarly united, all as
nearly as possible of the same size. Now the question is
whether this hypothesis extends also to uneven numbers, or
whether these specimens are merely three granules joined
together, and in an early stage of coalescence. Examples of
this form are not uncommon. In the specimen of starch
from which these were taken there was no difficulty in finding
them, being almost as common as the pairs. This starch

4 RAINEY, ON STARCH GRANULES.

was prepared from potatoes which had been kept nearly a
year. I have dwelt upon this form, as appearing to me rather
singular that it should not have been observed by more
botanists ; perhaps if it had been sought for as diligently as
the granules in pairs its existence would have been more
generally noticed. This observation may serve as a hint in
the examination of other structures in which the division of
cells into two is said to take place as in cartilage. I am
perfectly aware that triplets with granules of nearly equal
size will, as a matter of course, be less frequent than similar
pairs. Those represented in figs. 2 and 3 are a modification
of the dumb-bell shape, which is seen much better in the
smaller granules which unite before they lose their spherical
form. These may be well seen in thin transverse sections of
the very young houseleek, Sempervivum tectorum.

Figs. 6 and 7 are representations of a description of starch
granule, called by physiologists “compound granules.”
These have been variously explained by different authors, but
in all cases which have come under my notice the explanation
of the central part of such granules has been made dependent
upon some assumption which has been irreconcilable with
the principle of explanation applied to the peripheral part.*

Fig. 6 is taken from Criiger’s plate, as copied in the ‘ Micro-
scopical Journal.’ This copy, I may observe, is not intro-
duced here, from my being unable to obtain similar specimens
myself. They are frequent enough in the kind of starch
called “tous les mois,” but the facts very well shown by
these drawings will have more weight as coming from diffe-
rent and independent observers. These granules consist of
two or more simple granules, each having its own lamelle,
and the whole surrounded by common lamelle.

Fig. 8 is an accurate representation of two globules of
carbonate of lime from the calcifying shell of the oyster.
There is so striking a resemblance between the structure of
these and those marked fig. 6, that no one would question
their laminated structure aud their union as being otherwise
than the result of a similar cause, and very likely to be pro-
duced in both cases, either by the layers of increment
deposited on the inner surface of a cell-wall, or by the layers
deposited around a centre or nucleus. Such was the con-
clusion arrived at respecting these bodies by physiologists
before it was shown by me, in 1857, that exactly such
forms as that represented in fig. 8 could be produced
artificially, and that there were sufficient grounds for be-

* See these treated of in the April number of 1854 of the ‘ Quarterly
Journal of Microscopical Science,’ by Dr. Allman and H. Criiger.

RAINEY, ON STARCH GRANULES. +)

heving that the chemical and mechanical conditions which
were employed in the experimental process for obtaining them
existed in the animal organization, and therefore that both
kinds of carbonate globules were of the same structure and
produced under the influence of the same agencies.

Fig. 9 is a representation of some of the largest kind of
artificial globules joined together, and in progress of coales-
cence to form a single one, just as those represented by
fig. 8 are; and, doubtless, the globules of starch in figs. 6
and 7 are in a like condition of coalescence.

I will now proceed to the second part of this paper, that
is, to show that chemical and mechanical conditions similar
to those in the experimental process for obtaining carbonate
of lime globules, and which are necessary, on the same prin-
ciple, to produce these several forms of starch, exist in the
vegetable organization. This I look upon as the most novel
and important part of this communication.

Now, as it is a fact generally admitted, that vegetable
membrane is impermeable by solids, however minute may be
their particles, it can only be in the interior of the starch-
cells that starch can reeeive its solid form. Hence, there
must exist in solution in these cavities some fluid capable of
furnishing starch, or from which starch can be precipitated
on the access of a second fluid containing some one or other
of the constituents of starch in solution. Now, with respect
to the first solution there will not be much difficulty, as
dextrine—“ a soluble substance found in almost all parts of
plants’”—or some solution analogous to it, will fulfil this— the
first—condition. And as respects the second, the difficulty
is still less, as there is no known solution but that of gum,
which is diffused generally through plants. Hence, if starch
be produced upon the principle of precipitation, from a fluid
within thestarch-cell, asthe globular carbonate, andthemixture
of globular carbonate with phosphate of lime are in the hard
tissues of animals, there is no other solution but that of gum,
which, from its general diffusion in the tissue of these cells,
can precipitate it. Now, to show that these substances, under
the circumstances they exist in vegetables, will perfectly fulfil
all the conditions necessary for the formation of starch in the
cells of plants, I will give some out of the many experiments
which I have made for that purpose.

I will first show that gum possesses some remarkable pro-
perties which, I believe, are entirely unknown both to che-
mists and physiologists. One of these properties is its action
as a general precipitant of substances contained in solution
in the juices of plants, and the other is its action on dextrine,

6 RAINEY, ON STARCH GRANULES.

from which it precipitates a modified form of starch, and, on
an alkaline solution of starch, from which it precipitates
pure starch. To show the first property—that of a general
precipitant—it is necessary to obtain the expressed juice of
fresh vegetables, previously bruised or rasped, and filtered
through blotting-paper once or twice, so that it may be per-
fectly clear. Some of this juice is then to be filtered into a
test-tube, into which a small quantity of filtered solution of
gum arabic has been introduced, when, after these fluids
have remained for a few minutes, the stratum of juice in con-
tact with the solution of gum will lose its transparency, be-
come turbid, and soon deposit, in greater or less quantity,
the vegetable matter which it had held in solution. I haye
performed this experiment upon the juice of several plants,
and always with the same result. The juice of the bruised
stems of the potato, as also that of the rasped bulbs, will
serve very well for this experiment, and especially the latter,
as it can at all times be procured. I may observe, that the
filtered juice of some vegetables will, after standing a short
time, without the addition of any gum, become turbid and de-
posit of itself. But this deposit I have not mistaken for
that produced by the gum, the latter beginning to be appa-
rent within a minute or two after the contact of the gum
with the expressed juice, whilst the former requires several
hours, or an indefinite time, for its production. I may also
notice, that this property of gum is not, so far as I can dis-
cover, attributable to any earthy or metallic salt which it
may contain, or to the acid which is generated by it, after
being kept for some time in solution, but it appears to be
essentially a property of vegetable gum, that is, of a sub-
stance which forms with water an adhesive solution, from
which it is precipitated by silicate of potash, and thrown
down by alcohol in the form of opaque white flakes. As, in
order to be assured upon this point, I employed in my expe-
riments gum from which the salts of lime had been separated
by oxalate of ammonia, also gum which had been precipi-
tated from its solution in water by alcohol, and after that
dried and redissolved in water, also a solution of gum made
slightly alkaline, all with essentially the same result as that
obtained by the unpurified gum. I will now give some expe-
riments showing the effect of gum upon dextrine, and upon
starch dissolved in a solution of potash. It is well known that
dextrine is formed by heating starch, and also by the action
of sulphuric acid upon starch; I therefore obtained a
substance known in commerce by the title of soluble gum.
It is made by applying heat to starch in a suitable apparatus.

RAINEY, ON STARCH GRANULES. i

This, when put into cold water, affords a solution, which is
turned brown by the action of iodine. This is a solution of
dextrine. I also obtained a similar solution by mixing
potato starch with sulphuric, muriatic, and nitric acids. But
I generally employed that made with muriatic acid, in con-
sequence of its not precipitating the lime from the gum,
which sulphuric acid did, as a sulphate of lime, and henze
did not require purified gum to be employed in the experi-
ments with it. I employed, likewise, a dextrine made by
dissolving soluble gum in water with citric acid. This I did,
in consequence of the muriatic and sulphuric acids having a
particular action upon gum—that of converting it into a
transparent insoluble substance, which the citric acid does
not.

To show the effect of a solution of gum in precipitating
starch from dextrine, the same mode of experimenting as that
just described in reference to its action upon the juice of
plants maybe employed. One way which I have found con-
venient to demonstrate the action of gum upon a solution of
dextrine, is to put on a microscope slide a few drops of very
thick solution of gum, and on the top of that a drop or two of
solution of soluble gum, or of starch, acted upon by an acid, and
then to examine these with the microscope whilst the action
is going on, and without placing upon them any cover of glass,
when it will be seen that the solution of gum causes the
solidification of the dextrine starch in minute particles,
having a finely granular appearance. The two solutions seem
also to exert a repellant action on one another, and the
starch runs into globular forms, just as oil would do if placed
on water. ‘To show this fact, and the form given to the
starch, these solutions should afterwards be allowed to dry
on the slide, and a drop of solution of iodide of potassium,
containing also some tincture of iodine, added ; and then over
them a cover of thin glass may be placed. The form which
the starch had taken will be seen by the colour imparted
to it by the iodine. On washing these with water the circular
patches of starch will be broken up, but the starch itself will
remain solidified in granules of various shapes and sizes.
With a view to determine how far these effects might be
attributable to the medium in which the starch had been
dissolved, I dissolved some potato starch in a solution of
caustic potash, and, after having filtered the solution until it
was entirely without any solid matter, placed a drop of it
upon a solution of gum, and proceeded precisely in the same
manner as described in the last experiment. I found that
exactly the same effect was produced, that is, the solidifica-

8 RAINEY, ON STARCH GRANULES.

tion of the starch. After these had been allowed to dry on
the glass as before directed, the starch thus precipitated was
transferred from the slide to a watch-glass filled with water,
and allowed to remain until the gum was all dissolved, and
then it was washed several times. In this case it does not
alter its form, which is that of a granular areolated film of
solid matter, which, from the action of iodine upon every
particle of it; is shown with certainty to be starch. Potash
does not convert starch into dextrine like the mineral acid,
but seems to dissolve it nearly, or entirely, unchanged.*
The most easy way of demonstrating the effect of gum
upon dextrine is to mix some solution of dextrine,
made from soluble gum, dissolved in a solution of citric
acid (this acid is used only to get a stronger solution)
with the solution of iodine above specified, when a purple
brown fluid will result, then to put a few drops of it on a
glass shde close to a like quantity of clear solution of gum of
considerable density. These must be made to mix under the
microscope, and the effect carefully observed. The first
thing which will be observable will be the precipitation of
the starch in very minute granules, at first colourless, but
afterwards, and almost instantly, becoming blue or dark
pink. And, if the quantity of starch be considerable, the
blue colour will remain for several days without changing,
but, if only small, it will turn gradually pink, and so will
remain unless fresh iodine be added, when it will become of
a dark color. A part of the blue tint, at first produced on
adding the solution of gum, is the effect of the dilution of the
solution of the iodized dextrine, and can be produced by
water, but in this case there is no precipitation, and, as the
solution gets inspissated by the evaporation of the water, the
original purple-brown of the dextrine becomes restored.
For this experiment starch treated with muriatic acid, or,
sulphuric will not answer in consequence of a part of the
starch only being converted into dextrine, and the other
being held in solution, so that when the iodine is added
the latter is precipitated. When the solution contains only
dextrine nothing is thrown down by the iodine.

The result of these experiments, taken altogether, shows
that so completely is gum a precipitant of starch that it
matters not whether it is in solution in an acid, or an alkaline
menstruum, the effect is the same, although in these two cases
the characters of the starch thus deposited are, as before

* When potash is employed, the lime must be separated from the gum

by oxalate of ammonia, otherwise the granular film of starch will be studded
with particles of the globular carbonate of lime.

RAINEY, ON STARCH GRANULES. 9

noticed, more decided in the latter than in the former.
Now, gum is not the produce of any particular vegetable
cells, nor is it confined to any class of plants, but it appears
to be a secretion generally diffused through the tissues of all
plants. Hence, combing these two circumstances, the
general existence of gum in vegetables, and its property as a
precipitant, I hold that one of the conditions necessary for
explaining the presence of solid substances in the cells of
plants by a process of precipitation is demonstrated. I need
scarcely add, that the solution of gum would gain access to the
fluid within the starch-cells—all by aprocessofendosmose. And,
as to dextrine, it is generally admitted to be matter assimi-
lated in the cells of plants for the purposes of nutrition, and
therefore it is only necessary to suppose that in certain cells
some such a solution of starch, as that made artificially
by mixing starch and alkali together, is elaborated; (and
alkali, in some form or other, is well known to be essential
to the growth of plants,) and then we shall have the other
condition requisite for the same process. And with such
conditions there is no difficulty in seeing how a kind of mo-
dified starch, as cellulose, or the imperfect forms of chloro-
phylle, would be deposited in the former cells, those con-
taining the dextrine, and pure starch in the latter. I
am perfectly aware that this explanation will be considered
by the vitalists as being too physical, but still it is no more
so than the formation of bodies of a similar form in the shells
of Molluses and Crustaceans. The molecules of starch being
thus formed and deposited, will, after repeated coalescences,
produce all the forms described and represented in the
accompanying plate.

The form of some of the larger starch granules may appear
at first sight to have no representatives among the calcareous
deposits, either natural or artificial, but this is perfectly ex-
plicable upon physical principles, and, when duly considered,
is in favour of the principle of molecular coalescence. A
similar difference of shape, though not to so great an extent,
obtains also with the natural and artificial globules. In all
the three cases the most nearly spherical forms of single
globules are among the smallest, the mutual attraction of
their molecules upon which rotundity depends, being less in-
terfered with in these by the simultaneous attraction of sur-
rounding objects than in the larger globules, as would be
the case with globules of quicksilver of different sizes, placed
upon a piece of glass or a sheet of paper, the smallest would
be the roundest. As the particles get larger their molecules
become more effectively attracted by adjacent masses of

10 RAINKY, ON STARCH GRANULES.

matter, and thus the centre of attraction common to the
molecules of the globule in progress of formation, and the
surrounding particles of matter, towards which centre all
these molecules are effectively or ineffectively attracted,
cannot be the geometrical centre of the globule im question ;
and hence a globule formed under such circumstances cannot
be accurately spherical. These conditions must always exist
as well during the formation of the calcareous globules as
during that of the granules of starch, but they will operate
more as disturbing causes in the latter than in the former,
just in proportion as the molecules of starch are less dense
than those of carbonate of lime. Hence these peculiarities
in the form of the large granules of starch are no more than
might have been expected. The small granules of starch are,
to all appearance, as spherical as those of the carbonate of
lime of the same size. For an explanation of the manner in
which the granules of starch acquire their laminated form,
and the mode in which the hilum, the part corresponding to
the central spot in the artificial caleuli, is formed, I must
refer to my work on the ‘Mode of Formation of Shells of
Animals, of Bone, and of several other Structures, by a pro-
cess of Molecular Coalescence.’

I should have been glad to have introduced into this paper
a condensed account of this process, as given in the volume
referred to, had not the necessarily elementary character in
which the process is there explained rendered the necessary
abridgement of that explanation impracticable.

With respect to the chemical action of gum, and the
chemical nature of the deposits thrown from the vegetable
juices, I have not yet been able to make any strict investiga-
tion. I feel certain, from what I have noticed, that the sub-
ject is one of importance, and it is not impossible that it
may pave the way to the discovery of similar facts connected
with the action of the fluids in animal tissues. In reference
to the action of gum in precipitating starch, it is not im-
probable that, as starch contains a minute portion of phos-
phate of lime, which can only have been derived from the gum,
in which this salt is well known to exist, gum may furnish
other constituents of starch, and also some portion of all the
other substances which it has the power of precipitating, and
that thus it may act both as a medium by which the various
substances existing in plants are carried to the cells in
which they are elaborated, and as a means of solidifying them
after they have undergone the necessary elaboration,

1]

Descrirtions of Diatomaces, chiefly of those found in
“Erie” (Lower California) Guano. By CuristopHEer
Jounston, M.D., of Baltimore, U.S.

I am fully aware of the fallacies which beset the dia-
tomist who establishes new species from the inspection of
rare, isolated, and prepared valves ; but I am of opinion that
science is made the gainer by his efforts, provided he is care-
ful not to substitute names for things, and fancy for the sense.
If the observer states the circumstances under which he
obtained his facts, it is certainly pardonable in him to group
these together in such a manner as to guide others in extend-
ing the limits of knowledge, whether by verifying his speci-
fication, or by modifying it, when accumulated observations
justify the emendation.

Species have, doubtless, been disadvantageously multiplied ;
but it must be allowed that this error has not unfrequently
been innocently committed, either when descriptions in sys-
tematic works failed to identify supposed novelties, or the
published figures evidenced no correspondence with them.
Accurate figures are, unquestionably, of great service in
many respects, for they are duplicates, so to speak, of the
original specimen ; and “if they fail in some cases to esta-
blish species, they will, at least, assist to indicate the range
of variation, a point in itself of no small importance.” In-
deed, it may be said that exactness in description and
delineation must largely contribute towards lessening the
useless load of nomenclature with which science is charged.

The source whence the specimens here noticed were de-
rived was Californian guano, from the Island of Elide, on
the coast of Lower California (lat. 29° N.); Patagonian
guano; and the stomachal contents of oysters from Ponga-
teague Creek, on the Chesapeake side of the eastern shore of
Virginia.

Spataneipum, De Brébisson.

It would seem to be a superfluous task to recur to this
“noble diatom” with a knowledge of Greville’s delightful
paper on Diatomaceze which appeared in the April number
of this Journal. But I have thought it not unprofitable to
add to that author’s description of a single valve my own
observation of the appearance presented when both are
attached, for the character thus afforded is remarkable.

In isolating specimens preparatory to mounting in the dry

12 JOHNSTON, ON DIATOMACER.

way and in balsam, it was very easy to perceive that the
front view (or edge) of Spatangidum was not straight, but
sinuous or zigzag; and it occurred to me that the rays of
both could not coincide when the valves were together. I
was fortunate in finding three individuals in pairs such as I
had wished. The colour is darker, of course, than that of a
single disc; instead of seven rays there appear fourteen,
alternating in depth of hue; and the reticulation extends
uninterruptedly over the whole extra-hyaline area, but is
fainter in the course of a ray as it overlies the inferior inter-
radial network. Diameter 51,".

From ‘ Elide.”’

In the dry preparation all the rays are brighter than the
interspaces, and the reticulation over and under the former
more distinct.

ASTEROMPHALUS, Ehr.

Asteromphalus centraster, nu. sp.—Orbicular, of a pale
buff beyond the hyaline area, which is very slightly ex-
centrical. Rays straight, turgid in the area, diminishing
gradually, and terminating in a flattened nodule situated just
within the marginal line; nucleal ray longer and narrower
than the others, which are inserted on its extremity, and
very near it on the sides. The hyaline area has a scalloped
border, convex inwardly, each inter-radial space being bisected
by a delicate secondary ray terminating outwardly in a
nodule, and about three sevenths of the radius in length.
Margin very finely dotted, showing best in lines at right
angle with the secondary ray. The crescentic edge of the
hyaline area and the rays beyond it bordered with minute
granules.

The number of rays of this charming species is eleven,
and they are equidistant. I regret to say that I have found
but a single disc. Diameter 34y". (Pl. I, fig. 10.)

In Elide guano.

Campytopiscus, Ehr.

C. productus, n. sp.—Valve inconsiderably bent; elon-
gated and constricted at the middle. Canaliculi about one
fourth the transverse diameter, each marked by a small
node midway as it expands outwardly; margin broken by
depressions not corresponding with the canaliculi, and bear-
ing a double: row of small dots. Within the canaliculi, at
either extremity, an elongated crescent of fine granules
fading towards the centre. Diameters 74" x z4y".

In Elide guano.

JOHNSTON, ON DIATOMACE. 13

Of this and the following elegant species I have met with
but a single example, although I have searched diligently in
numerous preparations.

In the specimen above noticed the canaliculi numbered
thirty-seven.

C. marginatus, nu. sp.—Disc ovoid, bent; rays numerous,
marginal, short, separated externally by a nodule, and in-
ternally also by a larger one on either side of the trans-
verse axis; the inclosed field divided by a _ longitudinal
fusiform of smooth space; the remainder marked by rows
faint dots, straight im the direction of the transverse axis,
but becoming concentric with the extremities of the long
axis. Diameter z3y’. (Fig. 11.)

In Elie guano.

Cocconets, Ehr.

C. regina, n .sp., C. J.—Frustule ovoid, bluish green ;
striz numerous, 20 in 0:001”, concentric around the extre-
mities; on either side of the nucleal line the extremities
of the striz distinctly granular; in their course outwards
faintly moniliform, but more conspicuously beaded periphe-
rally, forming a sort of margin of the width of three or four
granules. Diameter zt)’. (Fig. 12.)

In Elide guano.

This exquisite species is not abundant in the residue fur-
nished by the guano. There is but little variation in size,
the diameter given above being that of the largest frustule I
have encountered.

Stauroneis, Hhr.

S. angulata, n. sp.—General form of the valve elon-
gated oval, extremities somewhat acuminate; the marginal
line bending on either side as it advances at about one third
the distance from the transverse axis, at which it makes a
wide but distinct angle. A narrow band of finely granular
striz, disposed transversely, surrounds a clear field, and,
becoming suddenly narrower at the extremities, is continuous
on either side of the carina with a delicate longitudinal band
of very minute granules, terminating in a point outwardly
at the stauros, which is short. Edge beaded. Diameters

eo |e mr eg ey
X 343 -

In Elide guano.
Heuiopetta, Ehr.

H. Phaeton, n. sp.—Frustule quasi-orbicular, many
sided, the number of sides being twice that of the rays.

14 JOHNSTON, ON DIATOMACE®.

Centre smooth; the surface of the disc presents alternating
wedge-shaped elevations (rays) and depressions, which
originate at the centre, the former pointedly; on each ray
there proceeds from a marginal nodule a delicate acicular
rib, which terminates apicially near the umbilicus, and in
the middle of each depression a delicate line. Very faint
indications of reticulation just within the margin. The
whole surface, exclusive of the centre, covered with extremely
minute quincuncially arranged puncta; and at the margin an
encompassing row of fine granules. Colour very pale straw.
Diameter +4;" to shy’.

In Elide guano.

In my specimens the rays are twelve in number.

Aracunorpiscus, Hhr.

A valve of Arachnoidiscus was found, which is interesting
as a variety of that genus, if it have not distinctive specific
characters. The centre is clear, immediately surrounded by
irregularly disposed granules, larger than those on the
general surface. In the same guano I found a number of
frustules, not distinguishable from A. japonicus, having
regular central rays, which is not the case with the one I
have delineated. Diameter 3},”.

In Elide guano.

AcHNANTHES, Bory.

A. angustata, Greville (?)—Front view.— Much bent.
Transversely banded, bands resolvable into dots, 26 in 0:001".
Half of the hoop transversely striated. A row of granules
along the base of each frustule, those of the upper one being
very fine. An apparent aperture (not an opening) at the
inferior extremities of the under valve. Length ;4,”.

Side view.—Both valves elongated, slightly swollen in the
middle, and with rounded extremities. Transversely banded,
the strie being rows of dots, interrupted by a line near to
and parallel with the margin. Externally the strie are
alternately swollen, giving the appearance shown in the
figure. Upper valve traversed by a central longitudinal
row of puncta, around which, at the extremities, the strize
are radiate. Lower valve similarly divided, but the ex-
tremities, instead of beg entire, appear to be largely per-
forated; in the clear space a crescentic line. Width +35".
(Fig. 13 a, 6, f.)

In Elide guano.

This species presents a striking contrast with the following,

JOHNSTON, ON DIATOMACEA. 15

which is also very beautiful; but while the form and the
markings differ, the general characters of upper and lower
valves are preserved.

A. costatus, n. sp.—Front view.—Curved, the superior
angles recurved upwards. Both valves transversely costate,
each row bisected. Length 743".

Side view.—Both valves with rounded extremities; the
edges nearly linear. On either side two rows of coarse
transverse strize, bounded by a line within the border. The
strie on opposite sides alternate, and their points form a
zigzag along the median line. The whole surface covered as
with a veil of extremely minute puncta.

The extremities of the upper valve exhibit a radiate dis-
position of the bands; whereas an apparent oval deficiency
exists in the lower frustule, but without the inner crescentic
line, as in A. angustata. Width zj5,”. (Fig. 144, 3, f.)

In Patagonian guano.

PLevRosicmMA, Smith.

P. makron, n. sp.—Has the general characters of P. Bal-
ticum, but differs from that diatom in its extraordinary
dimensions, its conspicuous convexity longitudinally on either
side of the keel, the coarseness of its markings, and the
attendant colour, dusky olive. Length ,4”; width 51,”;
dots 30 in 0-001" longitudinally, and 33 in 0-001" transversely.

Pongateague, Virginia.

P, —~.—Probably a variety only of P. Balticum. Length
44/3 width $5"; dots 36 in 0-001". Frustules slightly
swollen near the extremities ; and is of a deeper reddish-brown
than its congener.

Pongateague, Virginia.

I have had no opportunity of examining the diatoms of the
lower part of the Chesapeake Bay, except as derived from
oysters cultivated there. They occur, however, in rich variety
and profusion, embracing many beautiful species of Nitzschia,
Nayicula, Pleurosigma, Coscinodiscus, &c. But, from an
inspection of a considerable number of prepared valves (always
separate and viewed laterally), I think that P. makron may be
safely admitted as a new species; for although there is some
little variation as to size, the appearance of the valves, their
peculiar hue, and the distance separating the dots, remain
constant. The characters are, consequently, tranchés.

With regard to P. , there are, to distinguish it
from P. Balticum—\st, the length ;,”, while the latter is
but 7," by my own measurement; 2d, the turgidity of the

16 JOHNSTON, ON DIATOMACE.

frustule towards either end; and, 3d, the disproportion
between the two diameters—19 to 1; features sufficient to
establish a variety, but not, as was remarked by A. M.
Edwards, Esq., of such importance as to justify the erection
of a species.

It may be stated that Pongateague Creek, the habitat of
these large diatoms, is a shallow inlet of the Chesapeake
visited by the tide.

BaLTIMorE, MARryLAND;
May 20th, 1859.

We print the foregoing communication as containing de-
scriptions of Diatomacez from a locality which has hitherto
been little noticed, but as the author appears to have over-
looked the works of some writers in this country, we append
the following notes on some of the species by Professor
Walker-Arnott and Mr. F. C. 8. Roper.

Note sy Mr. Roper.

The species described by Mr. Johnston in the foregoing
paper appear, as far as I can make out from his descriptions
and the very well-drawn figures that accompany them, to be
mostly known to observers in this country. The fact that he
notices with respect to Spatangidum Ralfsianum, Grev., of the
rays in the two valves being disposed alternately, so that the
ray on the superior valve is opposité to the areolated portion
of the lower in the perfect frustule, has already been noticed
by Mr. Shadbolt,* in Asterolampra, a kindred genus, and, I
believe, is well known to be the constant rule in both Spa-
tangidum and Asteromphalus, should these genera, on more
careful consideration, prove distinct. They have been
adopted, however, by such acute observers as Dr. Greville
and M. De Brébisson, and though they appear to differ as to
the limits of each, my own impression is that both are formed
on one common plan, and should both be united under
Ehrenberg’s original genus of Asteromphalus, the differences
only being sufficient to afford specific characters.

Asteromphalus centraster, Johnston (fig. 10).—It is impos-
sible to form an opinion on this species without seeing the
specimens. The structure, both from the description and
figure, appears to differ materially both from the genus

* “Mier. Jour.,’ vol. ii, p. 17.

JOHNSTON, ON DIATOMACE. 1?

Asteromphalus, as defined by Dr. Greville,* and from the
genera Asteromphalus and Asterolampra, as described by
Ehrenberg.t The rays differ from any hitherto recorded
species of Asteromphalus, whilst the areolated segments,
being all equal and similar, and connected with the centre
by what Mr. Johnston calls the secondary ray, would seem
to show greater affinity to Asterolampra. It will require a
careful examination of many more than the single specimen
recorded by the author before its position can be safely
decided on.

Campylodiscus productus, Johnston. —A careful comparison
of the description and figure of this species with those given
of Surirella lata by Professor Smith,t and an examina-
tion of the variations that occur in any good gathering
of that species, will, I think, leave little doubt that they are
identically the same. The number of canaliculi is stated by
Professor Smith to be 3 or 4 in ‘001, and in his figure
there are 33 in all; in Mr. Johnston’s species there are
37. The length given by Professor Smith is ‘0041 to -0062,
whilst Mr. Johnston states his to be ‘0058. The only dif-
ference appears to be in the length of the canaliculi and in
the “crescent” of granules in the centre ; but as the markings
and canaliculi are subject to considerable variation in most
species of Surirella, this would be no good ground for specific
distinction.

Campylodiscus marginatus, Johnston (fig. 11).—The generic
position of this species is doubtless correct, but whether it can
be safely considered a new species from the examination of a
single valve may be questioned, as the only characters that
would distinguish it from the C. limbatus of M. De Brébisson§
are the greater separation of the canaliculi, and the more
strongly marked central area. In outline and general charac-
ter they are closely allied. Professor Gregory proposed the
same name for a species he detected in the dredgings from the
Clyde, but on consideration adopted the name already pub-
lished by M. De Brébisson, and has given figures and descrip-.
‘tion.|| The markings of the central area are a point of little
specific value, as has already been pointed out in regard to
Camp. Hodgsoni.§ .

Cocconeis regina, Johuston (fig. 12).—This appears to be cor-

* «Mier. Jour.,’ vol. xxvii, p. 100.
+ ‘ Berlin Proceedings,’ 1844, pp. 73, 198.
{ ‘Synopsis,’ vol. i, t. ix, f. 61.
§ * Diatomées de Cherbourg,’ p» 12; de ty fod.
|| Gregory, ‘ Marine Diatoms of the Clyde,’ t. ili, f. 5.
§| ‘ Micr. Jour.,’ vol. vi, Trans., p. 86.
VOL. VITI. Cc

18 JOHNSTON, ON DIATOMACER.

rectly referred tothis genus, and is probably anew and certainly
a fine species. The absence of any trace of central nodule
would seem to exclude it from Professor Smith’s definition
of the genus, but it is not unfrequently absent in the lower
valves of many species.

Stauroneis angulata, Johnston.—The correct position of
this species appears to have been misunderstood by the
author, as there is no true stauros, and there can be but little
doubt that it is either the Navicula Hennedyii of the ‘Synop-
sis’* and Professor Gregory’s Glenshira sand,t+ or a variety
of that form. It agrees closely in size with the dimensions
given by Professor Smith, and the whole structure of the
valve is identically the same.

Heliopelta Phaeton, Johnston.—The true generic posi-
tion of this species has also been quite overlooked, as any
reference to Ehrenberg’s description and figures of Heliopelta
would have shown. It ought evidently to be referred to one
of the numerous forms of Actinoptychus or Actinocyclus,
and is probably Actinocyclus duodenarius of Smith’s ‘ Synop-
sis, vol. 11, p. 86, or the Actinoptychus duodenarius of the
‘Mikrog.,’ t. xvii, f. 24. A description and figure of Helio-
pelta will be found in ‘ Silliman’s Journal’ for 1845, vol. xlviii,
p. 338, tab. vi, fig. R.

The Arachnoidiscus ? is the A. Ehrenbergit. See
Dr. Walker-Arnott, in ‘ Micr. Journ.,’ vol. vi, p. 162.

Pleurosigma makron, though large, and probably from
that cause with more strongly marked striz, agree so closely,
both in form and structure with P. Balticum of Professor
Smith, that there can be no grounds for theirs epara- tion
from that species.

Nore on Figs. 13 anp 14, py Dr. Watker-ARNotTT.

Both these forms clearly belong to the genus Gephyria,
established by me in ‘ Micr. Journ.,’ vol. vi, pp. 163-4, and
not to Achnanthes.

I have also stated in ‘ Micr. Journ.,’ vol. vi, p. 195, that
the Entopyla australis of Ehrenberg (‘ Berlin Proceedings,’
1848, p. 7) was perhaps the same as my Gephyria incurvata,
from Ichaboe, or, at least, partly so. I arrived at this con-
clusion principally from supposing that Ehrenberg’s sample
of guano was not from Patagonia, as he had been informed,
but from Ichaboe. Fig. 10, however, of Mr. Johnston’s,
taken from specimens from Patagonian guano, so far as I

* Smith’s ‘Syn.,’ vol. ii, p. 93.
+ ‘Micer.:Jour.,’ vol. iv, t. v, f. 3.

JOHNSTON, ON DIATOMACE. 19

can judge from the sketch unaccompanied by the description,
or notice of the number of costz in ‘O01, agrees perfectly
with Gephyria incurvata, so that presumptive evidence is
strongly in favour of the propriety of reducing my Gephyria
to Entopyla, and to this conclusion I some time since had
arrived; but on again examining with great care what
Ehrenberg says, I am now compelled to relinquish this idea,
and shall here quote from Ehrenberg, as translated in the
‘Ann. Nat. Hist., 1848, p. 343: “It (Entopyla) forms
quadrangular plates, which, seen from the side, are rounded
off above and below. These quadrate tablets or boxes consist
of several leaves like a book, which, however, are perfectly
connected. The leaves are parallel with the narrow sides
and curved; the two external leaves are like the cover of a
book, thicker, and marked with thirty-two longitudinal ribs.
The concave outer leaf is upon the ventral side, since it ex-
hibits two large roundish apertures at the extremities; the
opposite convex leaf has no aperture; all the intervening
leaves have a large aperture in the centre, leaving only a
thin margin; thus forming a large continuous space in the
interior of these little boxes. The structure of Biblarium
(Tetracyclus of Smith) is similar.”

He adds, under the specific character : “ In adult specimens
the middle leaves are almost (fere) sixteen in number, the
cost of the lateral leaves more than forty, separated by a
flexuous median line.’ From Ehrenberg in these descrip-
tions speaking of middle and outer leaves, without any other
distinction than those indicated, it appears to me that all these
were similar in general appearance ; in short, that the middle
leaves were what Smith calls annuli, as m Rhabdonema and
Tetracyclus, and not merely the connecting zone, dividing
into lamellz or thin slices, as are seen in some species of
Amphiprora, &c. Now Gephyria differs from Eupleuria by the
want of these cellulate annuli, and if Ehrenberg’s description
can be relied on, and it is too detailed to admit of a doubt, his
Entopyla australis can neither be a species of Gephyria nor
any species of Eupleuria known to me, and a question may
even arise if it belong to Eupleuria at all; it seems a con-
necting link between Eupleuria and Rhabdonema, from which
last it is distinguished by the dissimilarity of the valves or
outer leaves of Ehrenberg.

As to that from Elide guano, fig. 9, I have only examined
one perfect frustule and a few valves. It was first brought
under my notice in September, 1858, by Mr. A. M. Edwards,
of New York, who then informed me that he had detected
it in guano from Elide Island, California, about eighteen

20 JOHNSTON, ON DIATOMACEZ.

months previously, and had distributed it under the MS. name
of Scapha clathrata. Myr. Edwards at once recognised from
my description the identity of his Scapha with my Gephyria,
and it is in consequence of his strong remonstrance against
the union also of Entopyla that I have now revised the whole
subject, and have stated my opinion as above.

In the Elide guano form, it is doubtful whether Mr.
Johnston speaks of the dots or of the coste, when he says
there are 26 in ‘001; probably of the former, for, according
to my measurement, there are only 11 coste im ‘001 im all
my specimens. So that in this respect it is imtermediate
between G. incurvata and G. Telfairie. In general appear-
ance it resembles the latter more than the former, but
the valves are much more obtuse than in any specimen of
the species from Mauritius. How far these are sufficient
marks of distinction I have not materials to decide. If
these two be admitted as different, the one I indicated
(‘Micr. Journ.,’ vol. vi, p. 164) from the west coast of
Australia may prove a fourth; and I have observed valves of
the same genus from other places, but about which I can
offer no opinion without seeing perfect frustules. On some
future occasion I may have it in my power to elucidate all
the species more than I can do at present.

Gepuyris, Arnott (nov. gen.)

Frustules arcuate, attached (not ? forming a continuous fila-
ment), destitute of cellulate annuli and septa; connecting zone
sub-lamellate, finely striate on the surface. Valves arcuate,
with one median and several lateral cost, dissimilar:
inferior with the costz disappearing below the extremities of
the valve ; superior with them reaching the extremity.

1. G. incurvata.—Coste on the valve about 7 in ‘001.
Eupleuria incurvata, Arnott ; Acnanthes costatus, Johnston.

Hab. Tchaboe (in guano) ; St. Simon’s Bay, South Africa ;
Patagonia (in guano).

2. G. media.—Valves obtuse; coste 11 in ‘001. Scapha
clathrata, Edwards, MS.; Achnanthes angustata, Johnston
(not of Greville).

Hab. Flide Island, California (im guano).

In Botany clathrate implies that there are openings
between the. costa, so cannot with justice be applied to this
species.

3. G. Telfairie.—Valves cuneate, and acute at the ex-
tremities ; coste 15 in ‘O01.

Hab. Mauritius.

ON ABERRATION AT A CURVED SURFACE, Pat

To prevent mistakes may I recommend to your readers to
strike out from vol. vi, p. 8%, line ten from the bottom, the
words “or striate,” which are intended to apply to Eupleuria
incurvata, since remoyed to Gephyria.

The FUNDAMENTAL Proposition in the THEory of ABERRA-
tion (in Refraction) at a Curved SurFacre sIMPLY
DEMONSTRATED ; and a Test ESTABLISHED whereby the
InsurFicieNcy of the Approximate ForMULm (now in
use) for CatcuLaTine the ABERRATION at a SPHERICAL
Guass Surrace may be CORRECTLY ASCERTAINED. By
EH. M.

In the following paper I propose to treat on a subject of
great importance to working opticians, and which appears
to me to have been not very successfully handled by writers
on Optics.

Instead of giving a decided answer to the question I
propose to solve, mathematicians have hitherto considered
it sufficient to offer an approximate solution, supposed to be
correct enough for practical purposes. This is a poimt on
which I entertain a doubt, and my object in the present
paper is to give a completely satisfactory answer to the ques-
tion proposed, and to show, by an example, illustrating the
formula deduced, how far the usual approximation falls short
of the truth—in an extreme case.

I have added a geometrical proof of the truthfulness of
the formula, which may contribute to excite attention to
a subject the difficulty of which has, I think, been unneces-
sarily magnified.

For convenience I have also appended the arithmetical
working of the example.

Although I have not Potter’s book at hand, the correct-
ness of the substitution of the figures in his formula, which
is identical with Sir J. Herschel’s in ‘Encyclop. Metrop.,’
and Wood’s, &c., may be relied on.

PROBLEM.

Trace accurately the course of a given ray of light, QA,
after refraction at a given point, A, on the surface of a given

22 ON ABERRATION AT A CURVED SURFACE.

solid, of which AC is a section in the plane of refraction,
QCyq being its axis. The refractive index = m.

Here QC is given.

Also CD and DA co-ordinates of the point A.

Hence, also, the normal AE and subnormal DE may be
found.

Let Ag be the refracted ray required, cutting QCg in g.
Now sininc. :smnH :: QE: QA.

sin E : sin refr.:: gA : gE.

*, Sin inc.: sin refr.2: 4 2: 12: gA QA
ae ct ote es 4 ie QE’
. GA m.QA

| es OE = ¢ (a known quantity).
“. gA?= ¢*. gh*.

i.e. qi? + EA? + 2gk. ED = ¢*. gE*.
“. (2? — 1) gi’ — 2ED. gE = EA?

Aye VoD) EA?
EH? — =
4 e—)]° fe c—l
ED 2 ED? (ce? — 1) EA?
Age — ef eee
{9 =} (@—1* (c? — 1)
qh = : { BD + ¥{ ED? + (¢ — 1)Ea? } QEJ,.
ec —) wi

Let AC represent a section of a spherical surface (rad = EC).

The lines CD, AD, DE are given in the tables. Whence
find QA and QE; Let m = 3.

Ex. 1. Let AC = 40° AD = ‘64279 (by tables.)
QC = 2inches ..AD? = 4131789841
CE = 1 inch ED = ‘76604 (by tables.)
QESinches ».QA = 2324598
ce = 1:162299

e = 1350938965401

735099896401 = 4°94226 inches

“. q@ = 594226 inches,

73442
+ pB 173442

ON ABERRATION AT A CURVED SURFACE. 23
Ditto by Potter’s Formula (second approximation).

SPS 04a) Fo)

De rt 1:23954

ore
al 8 . 8
SOT 6°4.52 inches,
but Cg = 5942, as found above.
.. Error by approximation = ‘51 inches in excess.

ARITHMETICAL WORKING.

|
ll

AD = :64279
64279
mQ A. 578511
= 449953
ay)
QE 128558
EC = 1:00000 257116
ED = 76604 385674
“CD = -23396 AD?= :4131789841
QD = 2:23396 2-93396
QD = 2°23396
QA = 2324598 1340376
2010564
3 2324598 670188
ah Ge ee aah 670188
44.6792
= 1°162299 44.6792

QD? = 49905772816
AD? = -4131789841

43)140
129

462)1137
924

4644)21356
18576

46485)278026
232495
464909)4560157
4184181
4649188)37597600
37193504

404096

24 ON ABERRATION AT A CURVED SURFACE.

— 1162299
1162229

10460693
10460691
2324598

2324598
6973794
1162299
1162299

= 150938965401

.ci—1= 350938965401

ED= _ -°76604
"76604

306416
4596240
459624
536228
ED?= ‘5868172816
(c? — 1) EA?= = 350938965401

ED? + c?— 1° EA’? = ram a
§

186)1277
1116

1928)16156

15424
19363)73224
58089

193667)1513570
1355669

1936748)15790101
15493984

296117
ED = ‘76604
/ED? + c?— 1BA?= 968378

ED+VED?+¢c?— 1BA? = 1°734418

ww
ON

R¥LANDS, ON MARKINGS OF DIATOMACE.

1734418 ;
qh = 350938965401 — 4°94.222 inches.

350938965401)1°734418000000(4-94222
1 403755861604.
3306621383960
3158450688609

1481706953510
1403755861604
779510919060
701877930802
776329882580.
701877930802
744519517780
701877930802
426415869780

We learn, by a subsequent communication from H. M.,
that he has tried other arcs, as 15° and 10°, by the above
test, and finds that the error of the Formule of Approxima-
tion in these cases exceeds that which is here proved to exist
in the are of 40°.

He has also found that Mr. Potter’s third approximation is
incorrect as well as the second, which is given in the Example.

On the Marxines of DiatomacE#.
By Tuos. G. Ryztanps, Esq.

Iv is not easy to over-estimate the importance of the
department “‘ Notes and Correspondence” in your Journal.
Not only does it afford a means of recording facts which
might otherwise remain unpublished; but the various hints
and memoranda contained in it possess a value to the country
student which those only who are similarly situated can
appreciate. The note by Dr. Greville, ‘On a Structure
observed in Surirella,’ vol. vn, p. 116, recalled my attention
to the subject of the present article, and reminded me that
on two occasions I had observed something similar in
naviculoid frustules. The first was in Pleurosigma balticum,
where the internal marking was hexagonal; and the second
in a frustule of Amphipleura pellucida, where there were
transverse lines, but much more distant than the 130 to
‘001" observed in that species by the Hull microscopists.

26 RYLANDS, ON MARKINGS OF DIATOMACILE,

In neither of these instances were the slides my own, and
they were not seen under circumstances which enabled me
to do more than record the fact of their occurrence. In
neither case was the idea of a septum entertained; the
internal markings had distinctly the curve of the side of
the frustule, and the impression conveyed was simply that
both surfaces of the silica were marked. I had the less
hesitation in coming to this conclusion, from haying fre-
quently seen something similar, but apparently constant, in
certain disciform species. The fact that certain species of
Actinocyclus, &c., have two very evident sets of markings is
generally known. It is hardly less probable that the same
thing has been seen in Coscinodiscus centralis, and that the
fine secondary markings of Triceratium favus (indicated by
Dr. Wallich in what he calls 7. fimbriatum) have been
observed by those who have directed their attention to that_
species.*

It was while I was looking for the same thing in Coscino-
discus radiatus, that the importance of separating and dis-
tinguishing the several types of markings was impressed upon
my mind. Until they are so distinguished, their real value as
characters for purposes of classification must remain un-
known. How far I have succeeded in this investigation
remains to be proved, and when our knowledge will be suf-
ficient for practical purposes depends upon the attention
which observers may hereafter give to the subject. I may
mention that so long as observation is confined to perfect
specimens little progress will be made; fragments now and
then occur happily placed at the right angle for the purpose,
and convey more information at a glance than can be
obtained in hours from the ordinary side or front view of a
frustule.

With the hope that I may hereafter be in a position to
enter more fully into this subject, I shall refer now only to
those markings which bear upon the purpose for which this
article is written.

The siliceous portion of diatomaceous frustules seems
to be normally composed of two layers, more or less
intimately combined. The connexion may be simple and
entire, as in the case of Plewrosigma angulatum. Indi-
vidual specimens of this species are far from uncommon, in
which the outer “areolated” layer is partially removed,
leaving the inner layer entire. Isolated portions of the

* «Micr. Journ.,’ vol. vi, p. 247, pl. xii, figs. 4—9. I need hardly add
that the marginal fimbrie and the minute processes at the angles of the
hexagonal are also occur in British specimens of 7. Zavus.

RYLANDS, ON MARKINGS OF DIATOQMACEA. Pu

outer layer may be found upon the frustule, but I have
never seen them separated; the force which removes them
being apparently sufficient to break them up into single
“ areole :” the term in this case is very unfortunate, for
they are in fact hemispherical elevations. In other cases
the two layers are connected by septa arranged hexagonally,
or otherwise, after the fashion of a closed honeycomb. This
structure is figured by Dr. Wallich, in the article before
referred to, as occurring in his so-cailed Triceratium jimbria-
tum ; but he has overlooked the outer layer forming the lds
of the cells. In this case, the surfaces, both external and
internal, may be plane, or formed into slightly convex facets ;
they may be marked or otherwise. This is the Coscinodiscus
type, and will be found with certain modifications in Cosci-
nodiscus, Eupodiscus, Aulacodiscus, &c.

I find it difficult to avoid the conclusion that there are
two distinct materials present in the composition of these
layers, one of which acts much more powerfully upon light
than the other.

Again, the two layers may be so developed and combined
that the septa become, as it were, a skeleton in the more
transparent substance. Take the case of EKupodiscus Argus,
of which I have one or two most fortunate sectional views.
The outer convex surface is formed of a layer of transparent
silica produced into radiating lines of hemispherical projec-
tions; below this, and imbedded in the same material, are
the “areole,’ which are composed of the denser substance,
and are fragmentary or continuous, according to the size
and perfection of the specimen. The internal surface of the
valve is marked with minute dots. The following figures
represent the forms described :

Eup. argus. Lupodiscus

P Pl. angulatum.
Side of a single areola.

The small secondary markings in Triceratium are probably
simply elevations; but those of the connecting membrane,
like the coarser markings of the sides of the frustules, follow
the type of Coscinodiscus.

I have no positive evidence as to the nature of the material

28 RYLANDS, ON MARKINGS OF DIATOMACER.

with which the cell-like intervals between the septa are
filed. Burnt specimens—which I have not—would deter-
mine if it be fluid. It is occasionally wanting, and then
the cavities are filled with air. In the specimen of Trice-
ratium favus referred to, a large proportion of the areoli of
the connecting membrane contain air-bubbles. My present
impression is that the material is solid throughout.

There is a peculiarity very common, if not constant, in
markings of the Coscinodiscus type, which, in most cases, is
sufficient to determine it even from a front view alone.
The internal layer, at the base of each areola, is modified
internally, so as to produce a dark or light spot, as the focal
adjustment of the instrument is changed.

If the foregoing particulars be applied to the cases ob-
served by Dr. Greville and myself, I think the solution is
easy. It is not without some hesitation that I venture to
throw the slightest doubt upon an observation made by such
a man as Dr. Greville. Under ordinary circumstances I
should certainly not do so; but since the publication of his
article on Diatomacez in Californian guano, I am inclined
to shelter myself under the supposition that his working
instrument is not equal to the exhibition of these minutiz.
If this were not the case, we could hardly have been told
that the rays of his Spatangidum Ralfsianum terminate “in a
narrow lunate fold of the valve,” nor would he have pro-
posed to distinguish Spatangidum and Asteromphalus by the
areolated and the granulated structure of their valves. In
the first case the lunate fold has certainly no existence in
nature; the appearance results from the elevation of the
ray (as in Aulacodiscus) and the sudden depression at its
termination. While, in the second case, there is really no
structural difference whatever in the markings of the species
described, at least as far as regards S. Ralfsianum and A.
flabellatus, both of which follow precisely the Coscinodiscus
type; the latter, however, being considerably finer, requires
a proportionate increase of power.

Some Observations on the Structure of Nervn-Fisres.
By Josern Lister, Esq., F.R.C.S. Eng. and Edinb.,
Assistant-Surgeon to the Royal Infirmary of Edinburgh ;
and Witiiam Turner, Esq., M.B. Lond., Senior De-
monstrator of Anatomy in the University of Edinburgh.

Havrine recently had the opportunity, through the kindness
of Mr. Lockhart Clarke, of imspecting some of his beautiful
preparations of the spinal cord, we were struck with an
appearance which had not yet received a satisfactory inter-
pretation ; and, having been induced to investigate the point,
we have met with some facts which seem of sufficient interest
for publication.

For the sake of clearness it may be well to state briefly
the method employed by Mr. Clarke in preparing his speci-
mens.

A portion of perfectly fresh spinal cord having been
hardened by steeping in dilute chromic-acid solution, thin
sections are made with a razor, and these, after immer-
sion for a while in an ammoniacal solution of carmine, are
soaked in spirits of wine to remove the water, and then
treated with oil of turpentine. The last-named agent has
the effect of rendering the sections transparent, so that the
nerve-cells of the gray matter, finely coloured by the carmine,
are seen with the utmost distinctness, giving off in various
directions long branching processes ; while the nerve-fibres,
which are similarly tinted, may be traced with equal facility
in their course through the cord.

In the preparations which we saw, the cord had been sliced
crosswise, and in the columnar regions, where the nerve-fibres
have for the most part a longitudinal direction, the transverse
section of each fibre showed itself as a carmine-coloured
point, surrounded by a perfectly pellucid and colourless ring.
This was the appearance which seemed to demand explana-
tion ; the question being whether the transparent ring was a
mere space, resulting from shrinking of the object during
the preparation, or the white substance of Schwann (medul-
lary sheath) rendered transparent by the turpentine, the
axial cylinder alone, in that case, having received the carmine
colour. 3

It occurred to us that the point might probably be deter-
mined by applying a similar mode of preparation to some
nerve the dimensions of whose fibres could be readily ascer-

30 LISTER AND TURNER, ON THE

tained. With this view we steeped im chromic acid portions
of the sciatic nerve of a cat just killed, and also parts of the
spinal cord of the same animal; and having allowed them to
remain between three and four weeks im the solution, we
commenced the investigation in July of the present year,
1859.

A transverse section of the hardened sciatic nerve having
been placed for a time in the carmine solution and then
dried, we submitted it, without the application of turpentine,
to microscopic examination with a power of 130 diameters.
Viewed by transmitted light, it appeared as a confused opaque
mass; but, by reflected hight, it exhibited the structure de-
picted in Pl. II, fig. 1,* each nerve-fibre presenting in its
section a carmine spot, surrounded by a yellowish-white,
somewhat granular ring, which, though doubtless correspond-
ing to the pellucid rings in the preparations of the cord before
alluded to, was clearly composed of some solid material, in
short of the white substance of Schwann altered by the
action of the chromic acid.

We next examined sections of the cord treated in the same
way, but found that these dry specimens were so incrusted
with carmine that they gave no definite results. It happened,
however, that one of the sections treated with carmine still
remained moist, and, after washing away all superfluous
colouring matter, we examined it by transmitted light. A
very beautiful appearance now presented itself; carmine
points being seen in the columnar regions, as in Mr. Clarke’s
preparations, surrounded by rings; but the latter, instead of
being transparent like mere spaces, were dead white; the
carmine points, on the other hand, appearing in the thinnest
parts of the section as illuminated spots amid the general
opacity. This is represented in fig. 5.

It will be seen from this sketch, which is drawn on the
same scale as fig. 1, that the nerve-fibres varied very much in
their diameter, the largest being of about the same size as
those of the sciatic nerve, while others were of extreme
minuteness ; but in all cases in which they were sufliciently
large to be distinguished, they had the same character of a
white circle with a central carmine spot from one fourth to
one third the diameter of the whole fibre. It was obvious
that, in the cord, as in the sciatic nerve, the carmine central
part of each fibre was the axial cylinder, and the opaque
circumferential portion the medullary sheath; and, therefore,

* This sketch, like the others illustrating this paper, was drawn by means
of the camera lucida.

STRUCTURE OF NERVE-FIBRES. 31

that the pellucid rings in preparations treated with turpen-
tine consisted of the white substance rendered transparent by
that reagent.

The point at issue was thus satisfactorily decided ; but for
the sake of confirmation we made some further observations,
the results of which seem deserving of mention.

On examining the hardened sciatic nerve, without tinting
the preparations with carmine, we found that in extremely
thin slices the transverse sections of the nerve-fibres, viewed
by transmitted light, appeared as brownish rings with central
transparent colourless spots (see fig. 3), whilst by reflected
light the central parts appeared black, as shown in fig. 2. In
fact, under a low power the axial cylinders had, in these spe-
cimens of the sciatic nerve, as much the appearance of mere
spaces as the medullary sheaths had in preparations of the
cord treated with turpentine. But on applying a fine glass
of high power, a granular appearance was disclosed in the
pellucid central portion, showing that it was in reality a solid
substance, though of a transparency which was very remark-
able, considering that it had been so long subjected to the
action of chromic acid; and on afterwards treating similar
sections with carmine we found that this part alone became
coloured. The higher magnifying power also brought out
an appearance of irregular concentric lnes in the brown*
medullary sheath; and this, together with the granular
aspect of the axial cylinder, is represented in fig. 4.

These facts afford a very striking illustration of the essen-
tial difference in chemical composition between the axial
cylinder and the medullary sheath; the former being totally
unaffected by chromic acid, though the latter is rendered opaque
and brown and concentrically striated under its influence,
while, on the other hand, the axial cylinder, after being sub-
jected to the action of chromic acid, imbibes the carmine
colour with peculiar facility, although the medullary sheath
is entirely untinged by it.t

We next applied the high magnifying power to extremely
thin slices of the spinal cord prepared in the same way.
In transverse sections of the columnar regions the white

* It must be mentioned that a similar brown colour is seen in the super-
ficial parts of a cord which has been steeped in chromic acid, but the
deeper portions of the organ are comparatively only slightly coloured, so
that in individual nerve-fibres seen under a high magnifying power the brown
tint is not observed.

{ Ina boiled fresh nerve also the medullary sheath remains unaffected by
ammoniacal solution of carmine, while the axial eylinder assumes a distinct
though very faint pink tint —J. L.

32 LISTER AND TURNER, ON THE

substance of Schwann presented, in the larger fibres, the
same concentrically arranged appearance as we had ob-
served in the sciatic nerve, as is illustrated by figs. 6 and 7,
of which fig. 6 is one of the largest met with, being sty of
an inch in diameter, while fig. 7 is as small as 3,'55 of an
inch in transverse measurement. In the very minute fibres
no appearance of concentric lines could be detected, yet,
wherever the existence of an axial cylinder was indicated by
a carmine point, a ring of medullary sheath was always visi-
ble, presenting the same proportion to the axial cylinder as
in fibres of larger size. This may be gathered from figs. 8,
9, and 10; of which fig. 8 Seaeures xoo0 Of an inch across,
fig. 9 goon, and fig. 10 only za$55.-

“At the margins of longitudinal sections of the cord, the
contrast, both im structure and in tint, between the axial
cylinder and the medullary sheath showed itself very beauti-
fully. It often happened that a projecting isolated fibre
was, near its extremity, more or less divested of the white
substance of Schwann, so that the delicate, carmine-tinted
axial cylinder was exposed, though presenting here and there
colourless flakes of the medullary sheath adhering to its sur-
face; while in parts where the nerve was still entire, the-
pink colour of the central fibre could be distinctly discerned
through the intervening white substance. Fig. 11 repre-
sents a large fibre under such circumstances, and fig. 12 one
of considerably smaller size; and these sketches also display
the remarkable fibroid arrangement which we find the white
substance of Schwann invariably assumes under the influence
of chromic acid.

In conclusion, we may remark that the successive employ-
ment of chromic acid and carmine seems likely to afford
valuable aid in discriminating nerve-fibres among other
structures; there being, so far as we are aware, no other
form of tissue which, after the use of these means, exhibits
fibres having a central carmine axis, and peripheral un-
coloured sheath.

Supplementary Observations by My. Lisrrr.

The fibroid arrangement of the white substance of Schwann
in nerves hardened by chromic acid has been minutely de-
scribed by Stilling, in his elaborate treatise on the ‘ Nerve-
fibre and Nerve-cell,’* a work which we had not seen when

* «Ueber den Bau der Nerven-Primitivfaser und der Nervenzelle.’ Von
Dr, B. Stilling. 1856,

STRUCTURE OF NERVE-FIBRES. 33

the foregomg communication was written, but a copy of
which was kindly lent me by Professor Goodsir, soon after
Mr. Turner had left Edinburgh for the vacation. According
to Stillmg, the medullary sheath is, even in perfectly fresh
nerves, composed of a network of fibres, which are con-
tinuous with others in the axial cylinder and in the proper
investing membrane; so that, in his opinion, these three
constituents of the nerve-fibre differ from each other only in
the manner in which their elements are disposed.* This
view is not only quite novel anatomically, but is opposed to
the generally received physiological opinion, that the axial
cylinder is the essential part of the nerve-fibre, and the
medullary sheath an insulating investment. Considering
the high estimation in which the writings of Stilling on the
anatomy of the rervous centres are deservedly held, and the
influence which therefore attaches to his opinions, it seems
fortunate that we have been able to present so clear a de-
monstration that the axial cylinder is chemically as well as
morphologically totally distinct from the medullary sheath.

With regard to the cause of the fibroid arrangement of
the medullary sheath, an observation which I happened to
make several years ago, regarding the aggregation of fatty
matter, may perhaps tend to throw light upon the subject.
I submitted to microscopic examination some of the pulta-
ceous slough of a sore affected with hospital gangrene, think-
ing it possible that I might discover in it some fungus which
might account for the peculiar specific character of that dis-
ease; and found in it numerous bodies, each composed of
branching fibres radiating from a common centre, and look-
ing, at first sight, hke some sort of vegetable growth, so that
I made careful sketches of them, one of which is reproduced
in fig. 13. But seeing afterwards, in the same object, some
bundles of acicular crystals of margarine, having a distant
resemblance to the bodies I had drawn, I added ether to the
specimen, and found that it dissolved the latter equally with
the former. This showed that what first attracted my atten-
tion was merely an arborescent form of aggregation of some
fat, probably margarine ; and it seems not unlikely that the
fluid fat which exists in the medullary sheath of a perfectly
fresh nerve, may tend to a similar arrangement of its parti-
cles when passing into the solid form, and so give rise to the
appearance in question. It is to be remarked that the
fibroid character is not peculiar to specimens treated with
chromic acid, but also shows itself, though in a less perfect
manner, in nerves which have been subjected to other modes

* Op. cit., p. 6.
VOU. VIIr. =

34 ON THE STRUCTURE OF NERVE-IFIBRES.

of preparation—for example, after exposure for a few seconds
to a temperature of 212° F,

There is another important statement made by Stilling,
which the use of the method of examination above described
enables me to correct. He speaks of the fibres which con-
nect one nerve-fibre with another as similar in every respect
to those seen in the medullary sheath.* I find, however,
that both in the sciatic nerve and in the spinal cord of the
cat, the connective tissue between the nerve-fibres, like the
neurilemma and pia mater, with which it is continuous,
becomes coloured by the carmine; whereas, the medullary
sheath, as before stated, is quite unaffected by it, proving
that the two structures are chemically distinct from one
another. In both these situations, too, the fibres of the con-
nective tissue are much more delicate than the constituents
of the medullary sheath, which are often comparatively
coarse, as may be seen from fig. 11. In the columnar re-
gions of the cord, the former require a high magnifying
power to be applied to very thin sections, in order to distin-
guish them, and are often present in such extremely small
quantity that, without very careful examination, the nerve-
fibres appear actually in contact with one another. In the
sciatic nerve I have observed occasional elongated nuclei in
the connective tissue.

I may add that glycerine has proved very useful, not only
for permanently preserving the preparations in the moist
state, but also as an aid to investigation; for it renders the
sections much more transparent, without making the white
substance of Schwann invisible, as turpentine does; and
hence the course of the nerve-fibres through the cord can be
traced much more easily, and, at the same time, the propor-
tion between the medullary sheath and axial cylinder can be
readily ascertained. Thus, by examining transverse sections
of the cord in this way, I find that while Kolhker is quite
correct in his statement that the fibres of the roots of the
nerves diminish in size in passing inwards through the
columnar regions,t yet the diminution affects only the white
substance; the axial cylinder often retaining its full dimen-
sions even in the middle of the gray matter, while the medul-
lary sheath is reduced to a very thin crust, so that the nerve-
fibre assumes a character differing but little from that of an
offset of a nerve-cell.

* Op. cit., p.
t Kolliker’s Handbuch der Gewebelehre,’ 3d edit., p. 235.

On some Histotoeicat Features tn the Sue.us of the
Crustacea. By Professor W. C. Witi1amson, F.R.S.

In the Report of the British Association for 1848, Dr.
Carpenter called attention to the fact that the tegumentary
shell of the common crab chiefly consists of a tubulated
structure closely resembling dentine. Since the publication
of that report, the subject has been further investigated by
Professor Quekett (‘Lectures on Histology,’ vol. u, 1854),
and by Professor Huxley (‘Cyclopedia of Anatomy and
Physiology,’ art. Tegumentary Organs, 1855-6). Each of
these later writers have contributed much to our previous
stock of information on this subject. But as discrepancies
exist between the conclusions at which they have arrived, a
new investigation of the matter became desirable ; hence the
present communication.

Dr. Carpenter has described the shell of the crab as con-
sisting of three layers. ‘1st, a horny structureless layer
covering the exterior; 2d, a cellular stratum; and 3d, a
laminated tubular substance.” Mr. Huxley points out in
addition the existence of a soft uncalcified laminated struc-
ture, lining the inner surface of the shell ; consisting, in fact,
of similar layers to those external to it, but not yet calcified.
My examination of the shell of the common crab confirms
Professor Huxley’s conclusion that it consists of four hori-
zontal textures. Both Professors Carpenter and Huxley de-
scribe the outermost one as horny, but it is obviously calca-
reous, disappearing much more completely under the action
of solvent acids than any of the others. The second or
“cellular” layer of Dr. Carpenter is that respecting which
the chief difference of opinion exists. Professor Huxley
denies the “ cellular” character attributed to it by Carpenter
and Quekett, affirming that the cell-like areolze result from
a peculiar additional deposit of calcareous matter in the
uppermost layers of the shell. With this conclusion I
thoroughly agree, since oblique sections of the layer demon-
strate that the areole, which in their superficial aspect so
closely resemble epithelial cells, sink deeply into the sub-
stance of the shell, gradually becoming less distinct and
definite as they descend into its lower lamin.

Dr. Carpenter and Lavalle have designated the outermost
of these layers “the structureless epidermis ;” but I would

36 WILLIAMSON, ON SHELLS OF CRUSTACEA.

prefer applying to it the name of pellicle, since it only con-
stitutes a small portion of the true epidermal tissue of the
crab. In like manner I would designate the second, the
areolated layer, instead of employing Carpenter’s term
cellular, which implies what appears to be erroneous. The
third, tubulated layer, which all the above writers have shown
closely to resemble dentine, may be designated the calcified
corium, whilst the innermost layer described by Professor
Huxley may be called the uncalcified corium.

It is unnecessary again to describe the arrangement of
these layers. Dr. Carpenter has pointed out the tubulated
structure of the corium, and the inflections of its lamine,
which at numerous points ascend like flat-topped cylindrical
pillars, penetrating the areolar layer, and reaching the
pellicle, where they occasion the white spots seen on the ex-
terior of the crab’s shell.

The areole of the second layer, when viewed superficially,
present various aspects. Ordinarily they appear in the form
of dotted hexagonal spaces separated by translucent lines, the
former having defined outlines, which are darkest on the side
remote from the light, indicating projection and the forma-
tion of a shadow. In other cases the areole are of a lighter
hue than the intervening lines, which are dark and defined.
Oblique sections of these latter varieties show that at a very
little depth below their outer surface the dark lines pass
into others which are lighter than the areole; and still
deeper down, the areolz themselves become so merged, that
all distinct areolation ceases to be visible. These facts indi-
cate that the areolation is due to some conditions affecting
the surface of the areolated layer on the line of junction
between it and the pellicle. That this is the case will be
demonstrated by an examination of some other forms of
Crustaceans.

When viewed superficially, numerous vertical tubules are
seen in the areola. When a thin vertical section has been
quickly mounted in hot Canada balsam, so as to prevent the
latter from displacing the air in the tubules, these are suffi-
ciently conspicuous. ‘The entire layer is seen to be composed
of very thin lamin which follow the inflections of the sur-
face of the subjacent corium, and the direction of these
tubules is affected by the curves of the laminz, which they
penetrate nearly at right angles. On approaching the pro-
jecting pillars of the corium, the areolated laminz bend up-
wards, parallel with the sides of the pillars. Whether or
not the former are continued across the circular extremities
of the latter in a very thin and non-areolated state I am

WILLIAMSON, ON SHELLS OF CRUSTACEA. 37

unable to determine, but I am disposed to believe that
they do.

We often find a third modification of the areole, in which
the centre of each is occupied by a dark radiating spot re-
sembling a stellate pigment -cell ; and I have occasionally
seen in the common crab, a form identical with that seen by
Professor Quekett in a species of Portumnus, and which he de-
scribes as consisting of ‘‘ hexagonal cells having thick walls”
(‘Lectures on Histology,’ vol. 1, p. 393). No doubt exists
on my own mind that all these are mere varieties dependent
on slight modifications of the calcific process.

Pl. III, fig. 1, presents a diagram of the arrangement of the
layers in the shell of the crab; a@ being the pellicle; 4, the areo-
lated part with its smalltubules; d,the calcified corium with its
cylindrical pillars and vertical tubuli; and f, the uncalcified
corium. Recalling what I have said respecting the tendency of
the tubuli in the areolated layers to assume directions per-
pendicular to the plane of the lamine which they penetrate,
a glance at the diagram will explain the “ radiated cells” of
Professor Quekett, which he describes as surrounding the
pillars of the corium (loc. cit., vol. ii, fig. 256). In any
horizontal section of these structures, the tubuli at a distance
from the pillars would be intersected at right angles to their
direction, whilst near the pillars, owing to the change in the
plane of the component lamine, the tubules would be inter-
sected nearly in the direction of their length. Hence the
appearance of radiating lines in which Professor Quekett
could detect no cell-wall, and which he found so difficult to
reconcile with his idea of cellular structure.

The upper lamine of the corium are thicker than the
lower ones; and the undulations of the penetrating tubuli,
so characteristic of crustacean structures, appear to be de-
finitely related to the lamine through which they pass.
Towards the upper part of each pillar, the tubul bend
outwards from the same reason that those of the contiguous
areole are deflected from a perpendicular line, viz., the ten-
dency to penetrate the lamin at right angles to their plane.
I have not detected any branching forms amongst these
tubuli, though Professor Queckett thinks that he has observed
such.

Beneath the calcified corium is the thin wn-calcified layer of
the same tissue, which would ultimately have become calcified,
as fresh lamine were applied to its mner surface. When
detached from the calcified shell, which is readily done, it
presents numerous granular specks, which obviously corre-
spond with the tubuli of the calcified tissue. I have found

38 WILLIAMSON, ON SHELLS OF CRUSTACEA.

it impossible to satisfy myself whether or not these present
open apertures prior to calcification ; their minuteness and
the refraction of light which they occasion rendering the
determination of this point one of extreme difficulty. On
the peripheral surface of this membrane are numerous reni-
form specks having a reticulated aspect. The reticulations
resemble cells, and are not unlike the areole of the areolar
layer; but I believe them to be mere corrugations of the
membrane. The specks correspond with equally numerous
calcareous projections from the inner surface of the calcified
corium. On making a horizontal section of this surface, the
projections are seen to be perforated by larger and more
sparse tubuli than the contiguous shell, and which display a
disposition to areolation similar to what occurs in the corre-
sponding parts of the uncalcified corium. In other portions
of the same section, patches are often met with, unconnected
with the specks just referred to, in which there is also a
marked disposition towards areolation, as seen in Pl. III, fig. 2.
These areolz are sometimes hexagonal, but at others so irre-
gular as to preclude all idea of a cellular origin. The trans-
lucent reticulate lines separating the areole being merely
spaces from which the tubuli are absent.

Throughout the entire shell we find dispersed some cylin-
drical bodies which are either fibres or larger tubuli. These
penetrate all the layers of the shell. Tubuli similar to these
are very numerous in the structureless portions of the pellicle
immediately above the flattened summits of the pillars of
corium, from which they ascend to the surface of the
pellicle.

Before discussing the moot questions between the observers
already quoted, I would direct attention to some other
structures calculated to throw light on the debated points.

On making a vertical section of the tegument of the
common shrimp, we find the same number of layers as in
the crab, but in a much more attenuated form; but we
have also some new conditions of interest, some of which
have already been pointed out by Professor Huxley.

The areolar layer displays imnumerable delicate areole
(fig. 3), like those in the crab, but fainter in outline; both
these and the corium appear granulated in the horizontal
sections, either as the result of vertical fibrillation or from
tubuli. M. Lavalle has denied the existence of tubuli even
in the corium of the crab.

Professor Huxley rejects his conclusions in that instance,
but thinks him right in the case of the shrimp, where he
believes the granules merely indicate vertical fibrillation ;

WILLIAMSON, ON SHELLS OF CRUSTACEA. 39

my vertical sections, mounted in Canada balsam, appear to
oppose this idea. Some, at least, of these lines are filled
with air, indicating a tubular structure.

The very thin areolated layer is not so readily distinguished
from the corium in the vertical section as in some other
Crustacea, but I have obtained several evidences of its separate
existence as in the crab. The most remarkable feature in the
integument of the shrimp consists of numerous discs, the
result of a secondary calcification, which becomes incorpo-
rated with the pre-existing tubulated calcific deposit. Each
disc commences as a faint brownish ring, within which the
areole are at first visible, but the centre shortly displays
signs of consolidation, as in fig. 4; in which example the
deposit has commenced at the root of one of the short hairs
so abundant on this tegument.* The small discs thus
originated increase both in breadth and thickness, but
especially the former. Some of them assume the aspect of
figs. 5 and 6, where the dark radiating lines indicate a con-
dition of the calcareous matter resembling what is seen at
the first formation of the disc, and different from what occurs
in the intervening translucent parts, which appear to be more
consolidated. A translucent crucial figure is often seen in
the centre of each disc. But in the majority of instances, as
already pointed out by Professor Huxley, the discs assume
the aspect of fig. 7. Here the centre consists of numerous
small concretionary granules, each commencing as a separate
point, but which grow and coalesce by external concentric
additions until they unite to form a solid translucent
calcareous disc—strongly reminding us of what is seen in
the pulp-cavities of cetacean teeth. In fig. 8 some of these
granules are detached from the disc. When a portion of the
integument of the common shrimp is boiled in a solution of
caustic potass, though the soft chitinous element is not
destroyed by the process, it undergoes some change, revealing
an organic structure which does not hitherto appear to have
been noticed. The areolated Jayer seen in fig. 3 now presents
the appearance represented in figs. 9 and 10. It consists of
at least two layers of minute irregular concretions. Each of
these corresponds in size with one of the unaltered areole,
and I assume them to be identical, though unable to demon-
strate the fact. Each concretion appears to be formed by the
coalescence of a number of minor concretions. On examin-

* These hairs, which are tubular, are planted in uncalcified depressions
in the areolar layer ; a large branching tubule, ascending from below, pene-
trates all the layers of the integument, and, reaching the base of the hair,
communicates with the canal running along its interior.

40 WILLIAMSON, ON SHELLS OF CRUSTACEA.

ing the free margin of any of the segments of the body
after being treated with caustic potass, these granular con-
cretions will be seen in various stages of development
(fig. 10). Those nearest the free margin are small and isolated.
As we recede from the margin the granules coalesce and
become larger, receiving external additions, which cement
them together, and finally producing the structure just
described. The mode of calcification of the small areole
and of the larger discs, though at first glance appearing so
different, are thus demonstrated to be identical in all their
essential features ; though the process resulting in the large
discs is obviously a secondary one, being preceded by that
which forms the small concretions. The essential difference
between the two lies in the greater extent of the calcific
deposition in the former instance than the latter, as is proved
by the effects of heat in occasioning contraction of those
parts from which the larger discs are absent.

On decalcifying a portion of the integument thus treated
by means of hydrochloric acid, it presents precisely the same
appearance as the ordinary examples that have not been so
treated. Two distinct granulations are now visible; one on
the extreme outer surface of the membrane, apparently
belonging to the pellicular layer, and the other in the
areolated layer, if not also in the subjacent corium; the
second being the tissue which I believe to be tubulated. The
concretions represented in fig. 9 are absent from the points
into which the tegumentary hairs of the shrimp are planted.

Many of the smaller species of decapod Crustaceans reveal
modifications of structure throwing additional light on these
tissues so interesting to the physiologist. A few of the more
unportant varieties require notice.

In the British Hyas araneus* we again meet with the four
layers of integument. In the specimens examined, the
pellicular layer alone presented a deep-red colour, and ex-
hibited indisputable evidence that i¢ was composed of numerous
exceedingly thin parallel lamine. The areolated layer was of
a pale-yellow hue, and afforded equally clear proof that each
areola is the dome-shaped extremity of a six-sided prism, the
sides being contiguous with those of its neighbours, whilst
its substance is traversed by longitudinal tubuli. Owing to
the dome-like shape of the outer extremities of these prisms,
the outer non-tubulated pellicle appears to dip down between

* Tam indebted to my valued friend, Mr. Bean, of Scarborough, as well
as to a still dearer relative, whose name has been long associated with
the same place as one of its indefatigable naturalists, for the numerous spe-
cimens of British Crustacea upon which I have operated.

WILLIAMSON, ON SHELLS OF CRUSTACEA. AL

the areole, explaining the apparently intercellular reticula-
tions seen both here and in the common crab, as well as in
numerous other Crustaceans. The calcified and uncalcified
portions of the corium are much more distinct here than in
the common crab; since the former, instead of consisting
of continuous layers of equal thickness, appears in the form
of large hemispherical masses, the confluent bases of which
are directed outwards, whilst their opposite convex surfaces
project inwardly into a thick laminated uncalcified corium.
The parallel laminz of the corium continue their straight
course equally through the calcified and uncalcified portions,
demonstrating that the former are not secretions in the latter
pushing aside its layer, but irregular calcifications of their
substance. Tubular hairs are implanted in superficial de-
pressions in the integument, at which poimts both the
pellicular and areolated layers are wanting. The tube within
the hair is continued downwards through the entire thickness
of the corium, opening at its inner surface. A calcareous
cylinder surrounds this canal, even where it passes through
portions of corium otherwise uncalcified.

Similar, but still more strongly marked, conditions occur
in Pilumnus hirtellus, a vertical section of part of the carapace
of which is represented in fig. 11. @ is the pellicular layer,
which here (as is also the case in Hyas araneus) is the seat
of the deepest colour. 6 is the areolar layer, displaying
the dome-shaped areolz with remarkable clearness. These
domes are obviously portions in which the calcific matter has
assumed different conditions to those under which it has
been secreted in the superimposed pellicular layer. Each
areola displays some very delicate vertical lines.* Whether
or not these are tubes I have been equally unable to satisfy
myself, here and in Hyas araneus ; but, as I think that in
Portumnus depurator there can be no question that the areole
are tubulated, it is the more probable that the structure in
question is also tubular.

Large hemispherical concretions occupy the upper part of
the corium, the centre of each one of which is penetrated by
a vertical canal, prolonged downwards through the uncalcified
corium, but not surrounded in the latter part of its course by
a calcareous cylinder, as is the case with Hyas araneus.
Superiorly, each of these canals communicates with the base
of a large tubulated hair implanted in a depression penetrating

* Seen to the left of the drawing; from the opposite portion of which
they have been omitted, along with similar ones in the corium, to avoid
confusing the other characteristic features of the structure.

42 WILLIAMSON, ON SHELLS OF CRUSTACEA.

the pellicular and areolar layers. These calcareous concre-
tions display a coarse lamination, indicating the direction of
the laminz of the uncalcified corium, with which they are
parallel. They are also penetrated by myriads of the usual
undulating tubules, which appear to be prolonged, though
less distinctly, through the uncalcified corium. I see no
reason for doubting that the latter are tubuli as well as the
former.

In a thin horizontal section of this integument, made
through the upper part of the corium, which has been
decalcified (fig. 12), we see delicate circular areas, with
defined outlines and a central canal, indicate the position
occupied by the calcareous concretions. This is important,
since it shows that cell-like appearances may exist in the
decalcified membrane, which, nevertheless, are entirely due
to peculiarities of calcification ; cells having taken no part in
their origin.

Vertical sections of Portumnus depurator display even still
more distinctly than the last Crustacean the dome-shaped
cylinders of the areolated layer, and remove every possible
doubt that could remain as to the non-cellular origin of this
layer. The conclusion is inevitable, that the whole results
from peculiarities attending the process of calcification. It is
clear that in the Crustacea, two distinct co-existent calcifying
processes are very commonly in operation, the one resulting
in a more intense calcification than the other; their greater
density and higher refracting power giving to the former
the definite outlines seen both in the areolar layer generally.
and in the lenticular discs of the shrimp.

Professor Quekett describes the areolated texture as con-
spicuous in the crayfish. I have only examined young
specimens, but in them it was very indistinct, if not wholly
absent. I found the four layers revealed in the vertical sec-
tion (fig. 13), but the areolar layer (fig. 13 4) and the calcified
corium (fig. 13 d) occupied the greater portion of the sub-
stance, the pellicle (fig. 13 a) and the uncalcified corium (fig.
13) being very thin. That which is the obvious homologue
of the areolar layer in other Crustaceans is thick and very
distinctly tubulated, the tubuli being distributed with the
greatest uniformity. This layer would scarcely be distinguished
from the subjacent calcified corium but for its greater trans-
lucency.

An anomalous example of the common lobster furnished
new and interesting modifications of crustacean integument.
The pellicular layer was so thin as to be scarcely traceable.
The areolated layer, the chief seat of colour, was very distinct

WILLIAMSON, ON SHELLS OF CRUSTACEA. 45

both in the carapace and in the tail, though less so in the
claws; but the chief interest lay in the calcified corium,
especially at its peripheral portion. On looking at a vertical
section, the tubulated structure of this layer was rendered
confused and indefinite by some vague radiating elements.
On making a horizontal section immediately below the
areolar layer, the nature of these radiations became obvious.
The entire section was covered with regular hexagonal areolz
of exquisite beauty (fig. 14). Each areola consisted of
numerous irregular rods, radiating from a solid centre, sub-
dividing like the outspread arms of an encrinite, a resemblance
which higher niagnifiers only rendered more obvious, since
each radiating arm then appeared jointed; but this was an
illusion. The whole was but a congeries of botryoidal rods
(fig. 15), the result of a concretionary process of growth ; the
small tubercles with which each rod was studded being the
homologues of those seen in the large calcareous discs of the
shrimp. This structure was wholly distinct from the areolated
layer of the integument. Between these stellate objects,
there occasionally occur solidly calcified portions, often pene-
trated by a large vertical canal.

When a vertical section was decalcified, all these distinc-
tive features disappeared. I now only saw a series of parallel
chitimous laminze, traversed by undulating vertical tubules ;
the line of separation between the areolated layer and the
corium being very indistinct. Of these laminze I counted
about 60 in a section of the integument of the tail, whilst
there were 120 in the claw of the same individual, showing
that they are not consentaneously developed in all parts of
the animal. On the external surface of the lobster’s shell are
numerous small depressions ; at the hollow of each of these
are the orifices of several vertical tubes which descend through
all the subjacent tissues.

The hard calcified claw of the hermit crab further illustrates
some of these points. A vertical section made through one
of the numerous superficial tubercles (fig. 16) demonstrates
that these latter are the homologues of the white spots on the
shell of the common crab. We here see distinctly that the
uplifted layers of the corium (d) pass through the areolated
structure (4) and are brought into contact with the pellicle (a),
whilst the corresponding thickened portion of the latter, here
considerably thickened, is penetrated by tubuli or fibres (e)
similar to those seen in the homologous portion of the common
crab. This close relation of the upraised portions of the
corium to the pellicle, and the absence of the areolar layer
at such points, is also shown in Hyas araneus, Portumnus

44. WILLIAMSON, ON SHELLS OF CRUSTACEA. P

depurator and pusillus, and numerous other forms, which
illustrate an organization that attains its highest development
in the common crab; whilst in Portumnus depurator, the
diversion of the upper laminz of the corium from their
horizontality appears at its minimum.

Thus far it would appear that in all the Podopthalmous
Crustaceans, the integument consists of four layers. An outer
or superficial, almost structureless pellicle (a). An areolated
layer (4), but from which the areole may be occasionally
absent. <A calcified corium (d), and an inner layer of uncal-
cified corium (f), which may become calcified as newer layers
appear within it. Each of these layers varies exceedingly in
the relative development attained, but traces of each of them
always exist; each one becoming in turn the predominant
element in the integument of the various Crustaceans. The
corium appears to be more or less tubulated, whether calcified
or uncalcified. The areolar layer is often, though perhaps less
frequently so. Areolation does not appear to be confined to
the “areolar” layer, since it occurs on a small scale in the
corium of the crab and lobster; wherever it exists in the
examples which I have recorded, either of corium or areolar
layer, it is unquestionably the result of peculiar conditions
under which the calcific matter is deposited, and not of cellu-
lation. In the calcified corium of Corystes Cassevilaunus, we
find an illustration of the secondary calcification to which
areolation appears due. The lime exists in two distinct con-
ditions ; in the one it is equally diffused through the corium.
But within this are large irregular masses of a totally
different aspect evidently the result of a secondary process.

But Professor Huxley has already pointed out that areola-
tion exists in the uncalcified membranes of the articulations
of the claws of the common crab, where it cannot possibly be
due to any process of calcification. In the latter example
the areole appear to me to be tubulated portions of integu-
ment, and the intervening reticulate lines to be merely spaces
from which the tubules are absent, as is unquestionably
the case in the areolz sometimes seen in the calcified corium
of the common crab. Areolation appears to me invariably
accompanied by tubulation, whilst the variations in the
arrangement of these tubules, and the peculiar calcification
which renders the areolze so visible, appear to be common
results of some single cause. What that cause is, remains to
be ascertained.

There still remains for consideration the question of the
origin of these various layers, and their relations to the
deeper portions of the crustacean integument. Of course it

WILLIAMSON, ON SHELLS OF CRUSTACEA. 45

would be very desirable, were it possible, to examine each
of these species immediately after it had cast its shell,
tracing the various changes the new integument undergoes
in its progress to maturity. Unfortunately, mland students
have not the facilities for such inquiries enjoyed by their
more fortunate fellow-labourers who dwell on the sea-coast ;
but it occurred to me that much of the requisite information
might be obtained from the hermit crab. As is well known,
the claws of this species are as thoroughly calcified as those
of any other Crustacean. The anterior extremity of the
carapace is equally so; the posterior portion of the latter
slightly, if at all; whilst the abdominal segments are as
devoid of calcific matter as any crab that has just cast its
shell. We are thus enabled to ascertain, without difficulty,
the relations between the superficial layers and the subjacent
derm or endoderm of Huxley. The careful study of this
species has satisfied me that a well-marked basement mem-
brane interposes at all stages of development, between the .
cellular endoderm or derm and the tubulated layers, whether
calcified or uncalcified; and that consequently the cells of
the endoderm cannot enter histologically into the outer tegu-
mentary layers forming the crustacean shell.

The true derm or endoderm of Huxley, in the hermit
lobster, is thick and full of nuclei, colourless cells, and red,
blue, and brown pigment-cells. A section of the entire
integument of the soft carapace is represented in fig. 17,
where g indicates the derm, / its cells and nuclei, 7 its
pigment-cells, k the basement membrane, 6 the cortum and
areolar layers blended, and a the pellicular layer. The pig-
ment-cells are sometimes stellate, at others appear as
rounded granular bodies. Fibrous threads often interlace
amongst the cellular elements. The basement membrane is
a thin tissue of the most delicate character. The appearance
represented on looking vertically through this membrane at
the subjacent derm is delineated in fig. 18, where the letters
indicate the same parts as in fig. 17. The uppermost
cells of the derm (18) are larger, more turgid, and more
regularly distributed in the deeper parts of the tissue, remind-
ing us of the aspect of cartilage-cells in growing bone
near the line of ossification. Immediately above the base-
ment membrane is seen a layer of membrane (fig. 17 4)
with a granulated texture. In the wholly uncalcified parts
of the integument this membrane is scarcely visible ; but it
becomes more so as we approach the head, where it pre-
sents a faintly areolated structure, like that seen in the
shrimp, whilst numerous patches occur in which the areola-

46 WILLIAMSON, ON SHELLS OF CRUSTACEA.

tion is very distinct, especially in the anterior parts of the
carapace. This tissue obviously represents both the areolar
layer and the corium of fig. 16. In some parts of the tail,
where I have been unable to detect this tissue, its place is
occupied by a structureless pellicle apparently identical
with that represented in fig. 16 a: since I have distinctly
traced its extension over the granular layer where the latter
exists. On tearing a semi-calcified portion of the carapace
in which the areolee were but faintly discernible, the torn
margin appeared defined and angulated, corresponding with
the inter-areolar lines, proving the latter to be lines of less
perfect cohesion than the rest of the tissue. On decalcifying
the fragment thus torn the areole almost entirely disap-
peared, demonstrating how much they owed to conditions of
calcification.

The above example appears to throw direct light on the
genesis of crustacean integuments. It is clear that no cells
exist external to the basement membrane ; they all underlie it.
Whether or not the basement membrane is cast off along with
the exuviated shell has not yet been determined, but probably
such is not the case. The cellular derm appears to be the secret-
ing organ, producing the tegument, which latter permeates
the basement membrane by exosmosis, when in a fluid state,
and becomes consolidated into a structureless layer external to
the membrane. The laminz first formed are apparently those
constituting the pellicle, then those constituting the areolar
layer, and subsequently those forming the corium. Calcifi-
cation of these layers, both in its primary and secondary
varieties, is a process occurring subsequently to the formation
of the membranous lamelle, and probably due to some
protoplasmic fluid conveyed into the tissues by means of the
tubuli with which they abound. Prior to the formation of
these lamine some of the cells of the derm or enderon
change their form and position. The tubuli themselves pro-
bably exist as such prior to calcification; the latter only
rendering them more distinct.

The process of calcification appears to be identical with
what I have elsewhere shown to occur in the genesis of the
tooth of the Echinus (‘Journal of Dental Science’) and
in the scales and bones of fishes (‘ Phil. Trans.’) Com-
mencing as a granular point, each calcareous atom increases
by concentric additions to its exterior, leading to cohesion of
separate particles, and consolidation of the entire tissue. As
no cells are traceable in the chitinous layers of membrane,
the formation of these granules, it must be admitted, goes on
independently of any direct cellular agency.

WILLIAMSON, ON SHELLS OF CRUSTACEA. 47

The laminated structure of these calcareous concretions 1s
beautifully shown by some examples I met with in a very
small Australian crab. The fleshy substances in the claws
were dried up, but in their interior were numerous botryoidal
concretionary masses, the structure of which, as revealed in
thin sections, is represented in fig. 19. The concentric lami-
nation is here so obvious, that no question can arise as to
the mode of increment, whilst the masses appear manifestly
to be but enlarged illustrations of what we found on a smaller
scale in figs. 7, 8, 9, 10, and 15. Numerous dark points ex-
isted in these concretions, as represented in the lower part of
the figure, but which are omitted in the upper part, in order
to display the completeness of the concentric lamination.

We are thus compelled, equally from an examination of
their mature states, and from their development as traced in
the hermit crab, to reject Dr. Carpenter’s hypothesis of the
cellular structure of the areolated layers of crustacean integu-
ments. At the same time, they illustrate how a cellular pro-
toplasmic structure may secrete a tubulated tissue, closely
resembling dentine, from which it is separated by a struc-
tureless basement membrane, through which neither cells
nor nuclei ever pass. Whether the cells represented in
fig. 18 have anything to do with determining the position of
the areole in the calcified layers I cannot say, though I
doubt their doing even that much, since the spaces they
occupy do not seem to correspond with those of the areole ;
nevertheless, the question is worth further investigation, could
Crustacea, that have just moulted be obtained for examina-
tion.

48

On the MEasuREMENT Of the Stria of Diatoms.
By J. D. Soxurrr, Esq., Hull.

A paper having appeared in the ‘ American Journal of
Science’ for March, 1859, by W.S. Sullivant and T: G.
Wormley, on the ‘‘ Measurement of the Striz of Diatoms,”
I think it necessary to make a few remarks on their obser-
vations, in order to endeavour to prevent the spread of
far greater errors on this interesting point than those which
they consider they have corrected. As the subject now
stands, it is very similar to the men with the chameleon; and
had Messrs. Sullivant and Wormley, before publishing their
paper, made themselves better acquainted with all the varia-
tions in the markings on the Diatomacez, they would have
come to a different conclusion to what they have done. To
show that this is the fact, I will first call attention to the
Pleurosigma fasciola. Of this diatom the kind we find near
Hull are very small, and consequently the markings extremely
fine, the finest being, as I have before stated, 90 in the
tdyoth of an inch; but the Fasciola we get from Boston, in
Lincolnshire, are many of them so large that there are not
more than 50 strize im the z,/j5th of an inch. I have fre-
quently seen the longitudinal and cross striz at the same
time on the largest-sized Fasciola, from Boston, with the
half-inch objective, either of Ross or of Powell and Lealand ;
but the finest we find at Hull will defy even Powell’s one-
sixteenth, with 175° of angle of aperture, to show the same,
use what illumination you may. The length of the finest Hull
Fasciola is under 349th of an inch, whilst some of the Boston
Fasciola measure more than 44 5th of an inch in length.
Again, in the P. strigosum, I may observe that those from
the coast of Sussex have their markings very strong, even
stronger than set down by Messrs. Sullivant and Wormley ;
but those we find at Hull, and which were first named Strigo-
sum by Mr. Harrison, in 1846, have exceedingly fine mark-
ings on them, varying from 72 im the ,,5 5th of an inch
up to nearly 80. With regard to the striz on the Nitzschia
sigmoidea, we have another very striking instance of how
little we know respecting the markings on the Diatomacer.
I have one slide of this diatom, on some of which the mark-
ings are very strong and easily seen, whilst others, in the
same slide, set at defiance every method of illumination to

SOLLITT, ON STRILE OF DIATOMS. 49

bring them out, and I have little hesitation in a. that
the strie on this diatom. vary from 65 in the 755th of an
inch up to a degree of fineness which no lenses that we now
have will show. I have always found the various kinds of
Nitzschia to be the most irregular in the number of their
striz in the inch, of any Diatomaceze that I have studied.

The Navicula rhomboides is another instance of the impos-
sibility to give correct measures .of the number of striz on
any diatom. Our American friends have set the number
down at 70 in the ,,5,th of an inch, Smith says 85.
I have one or two specimens of this diatom that have
not more than 60 in the y455._ I have others, again, so fine
as to defy all means of showing the striz on them, and those
all in the same slide and of the same gathering. I could,
if necessary, apply similar observations to all the different
diatoms of which our American friends have given us the
measurement. Had they been acquainted with those facts,
I think they would never have published what they evidently
consider their standard of correctness, nor would they have
tried to prove that all other observers except themselves were
in error.

Nothing leads to such great mistakes in scientific inquiry
as too hasty conclusions. I consider that all their measures
are correct, as far 2s they have gone. They have played the
air very well, but they have neglected the variations.

I may further observe that our American friends are not
to come to the conclusion that all the measures given in
Smith’s ‘‘ Synopsis” are his own, as I know for a fact that
many of them were communicated to him by others. He
was a most indefatigable observer; but one man cannot do
everything, and the great wonder is the correctness of most
of the measures which he has given for diatoms of a medium
size.

I now come to Messrs. Sullivant and Wormley’s remarks
on the Amphipleura pellucida. They say, “We have not
been able even to ‘ glimpse’ the striz on this diatom. Messrs.
Harrison and Sollitt, in their paper above cited, estimate
the striz at 125 to 130 in the 5,5,th of an inch.” They
further add: “In conclusion, we may remark that our ex-
periments are confirmatory of the generally received opinion
that striez closer than about 85 in the z,/55 have not yet been
resolved.” In their measurement of those diatoms the striz
of which they have been able to see, I have no doubt of their
general correctness; but their remarks on the A. pellu-
cida put me in mind of the fine. double star, » Corona,

VOL. VIIT. E

50 SOLLITY, ON STRIZ OF DIATOMS.

first seen double by Dr. Herschel, and on which a writer
makes the following remark : “ Many a star-gazer has bravely
turned out on a bitter cold night and stared at n Corone
until every particle of his patience and caloric have been
fairly frozen out, and his eyes cried for mercy, without ever
being able to ‘glimpse’ this delicate object; and then he
comes to the conclusion that those who said they had seen it
double had never done so.’

Under the circumstances in which I am placed by the
uncalled-for remarks of our American friends, it will be ne-
cessary for me to show that the striz on A. pellucida have
not only been seen by myself and many others, but by
showing this to prove that their conclusion respecting the
impossibility of seeing striz closer than 85 in the z,55 1s
incorrect.

Many parties in this country have been under the same
false impression with respect to the visibility of those very
close striz, but all that I have met with, and to whom I have
shown the strize on the A. pellucida, have, after seeing them,
altered their opinion.

The clever microscopist, Mr. E. J. Lobb, of 148, Cheapside,
thus writes to me: “ Mr. Ross, Mr. Hewitt, Mr. Roper, Mr.
Powell, Mr. Lealand, and many others, have all seen the striz
on the Amphi. pellucida clearly defined by me at my house.
Mr. Ross told me he came a sceptic, but went away con-
vinced.”” My friend, Dr. Munroe, of Hull, can also bring
out the striz on this diatom very clearly, and he has shown
them to a great many very first-rate microscopists, and whom
he has also instructed in the proper method of manipulation
for showing them. Mr. Harrison has likewise done the same
thing with many others.

If what I have here stated be not sufficient to convince
our American friends that the striz on the 4. pellucida can
be seen, then the only thing I can suggest is for them
just to take a trip across the Atlantic, when we shall have
much pleasure, not only in showing them the stm on this
diatom, but also in giving them such instructions in manipu-
lation as to enable them for the future to see the same things
in America that we can see in England, and I think, also,
to convince them that if the striz, the distance of which is
85 in the z,455, can be seen ; with proper means, those which
are only at half that distance can be seen also. In conclusion,
I send you some of my most recent measures of the distance
of the striz on a few of the better known Diatomacez in
sveoth parts of an inch.

SOLLITT, ON STRIZ OF DIATOMS. 51

P. strigilis : 30 : cross striz.

,, formosum . 32 down to 20 oblique do.

», Balticum =. 40 = 20 cross do.

» quadratum . 60 A 35 oblique do.

.» hippocampus 45 . 40 cross do.

» attenuatum . 46 re 35 ditto.

Spe OpeNcerily ” \. 50 genuine specimen from the late J. W. Bailey.
» strigosum. 80 down to 40 oblique striz.
» angulatum . 51 “ 46 itto.

;, fasciola : 90 x 50 cross do.
N.rhomboides . 111 a 60 ditto.
A. pellucida 2 ESO Es 120 ditto.

My friend Mr. Lobb is of opinion that the estimate of the
strie on the last of those diatoms is even too low, as he
thinks they ought to be set down at 140 in the z,455th of an
inch. From all the above remarks I should like to know
what we are to call authenticated specimens. And I think
the only conclusion we can come to is, that there is here a
very wide field for future observation. The above differences
in measurements of the various diatoms do not make them
the less valuable as test objects for microscopes, but when
used as such, the observer ought always to know what he is
looking at.

TRANSLATIONS.

On the DistincuisHine of Exrvations and Depressions
under the Microscorz. By Dr. H. WrELcKeER.

(‘ Zeitsch. f. ration. Medicin,’ 3 ser., Bd. vii, p. 63, 1859.

Ir cannot be contested that the most important point in
every microscopical investigation is the correct interpretation
of the visible image presented to us. But, as in the latest
classical work by Dr. Harting (‘Das Microskop,’ &c.) the
subject of Microscopic Diagnosis does not appear to me to
have been treated so fully or so correctly as it might have
been, I venture to recur to the subject, which has already
been noticed by me in papers on Microscopic Technology
formerly published in this Journal.*

I. On Diagnosis by oblique illumination.

Dr. Harting considers that minute elevations and depres-
sions on microscopic objects may be readily confounded,
owing to the circumstance that each is indicated under both
transmitted and direct light by a shadow (Schlagschatten),
which may be exactly alike in either case; but whose posi-
tion as regards the source of illumination does not in micros-
copic vision immediately indicate the true form of the
object, as it does in ordinary vision,—for the reason, that the
requisite point of comparison is, in the former case, more or
less wanting. But in the compound microscope a deception
may more readily arise ‘because the whole image here
appears inverted, and the shadows consequently fall in a
direction opposite to the true one ;—that is to say, in the case
of an elevation they are directed towards the source of light,
and the reverse in case of a depression.”

* ‘Zeits. f. rat. Med.,’ 2 ser., vi, p. 172, and viii, p. 241.

WELCKER, ON MICROSCOPIC DIAGNOSIS. 53

In opposition to this, | would remark: that in transmitted
light there are no shadows (Schlagschatten) at all, and in
direct illumination only when the light falls upon an opaque
object. If an opaque object having vertical elevations on its
surface be viewed under the simple microscope by direct light
every elevation will exhibit a shadow on the side which is
turned from the light. But if a transparent object, that is to
say an object which acts as a lens—as for instance, a starch
granule lying on a black surface—be viewed with a lens by
direct light, the less illuminated side of the granule, but
which is obviously not in shade, will be that which looks
towards the light, whilst on the opposite side will be exhibited
its focus. That this distribution of the bright and dark, due
to the lenticular nature of the object, is, it must be confessed,
deceptively similar to the light and shade of ordinary illumi-
nation, I have already (loc. cit.) remarked.

In cases where, by transmitted light, a visible shadow is
exhibited, this is always consequent upon oblique illumination
(whether produced by a lateral position of the mirror or of
the diaphragm, or in any other way, is immaterial), and it is
only to such cases that Harting’s statements above quoted
can refer, although in the section in which they occur the
expression “ oblique illumination” is not employed.* But
when Harting says that the shadows of an elevated object,
owing to the reversal of the image in the compound micro-
scope, fall on the side looking towards the light—it is obvious
enough that that is the side on which a “ shadow” must be
placed. But the phenomenon is not so at all, for we find that
the supposed shadows of elevated objects viewed in the com-
pound microscope are situated on’ the side which looks from
the mirror.

The supposed “shadow” of convex transparent objects, as
I again repeat, is not a shade at all, but it is the less illumi-
nated portion of a body which acts like a convex lens. In
the simple microscope we perceive the focus which is turned
to one side by the oblique illumination, on the side looking
from the mirror, and in the compound microscope on that
which looks towards it.

II. Diagnosis by movement of the tube.

For the distinguishing of elevations and depressions

* Tn § 201 it is expressly stated that oblique transmitted light acts in
exactly the same way as does the oblique position of the object, that is to
say, by the production of shudows.

54 WELCKER, ON MICROSCOPIC DIAGNOSIS.

Harting (§ 885) further recommends the “ changing of the
distance of the object,’ which in most cases suffices, unless
the elevation or depression be altogether inconsiderable.
But it is precisely in the latter case, in which according to
Harting the movement of the tube leaves us in the lurch,
often that the determination appears to be most important
and desirable. In this case, it may be necessary, according
to the same author, ‘‘ to view the object in a direction per-
pendicular to that in which it was first placed ;” and he cites
the acetabular depression of the blood-corpuscles, and the
hollows on lignified vegetable cells, as imstances in which
this kind of profile view affords the wished-for result. But
how often is it not altogether impossible so to place certain
small objects in such a position, or to procure such a section
of them, as would exhibit the elevation or depression in
question, in profile? In these cases, however, I would
suggest as a means of diagnosis the elevation and depression
of the tube, inasmuch as I have proved that the most minute
punctiform elevations and depressions, whilst acting as convex
and concave lenses, exhibit different optical characters. The
course of the rays of light through spherical objects, some of
which act like convex and others as dispersive lenses, is ably
discussed by Harting (§ 275) and illustrated by figures; but
I do not find that he has either confirmed or contradicted
my statement, that all extremely minute convex and de-
pressed objects, as representatives of which I adduced the dry
spermatozoid and the lines on a micrometer, appear black
or light according to the position of the tube (the convex
appearing light on the elevation and the depressed on the
depression of the tube), and that this phenomenon is refer-
rible to the lenticular property of the objects, and affords a
certain, frequently the only means by which to judge of
their figure.

This is not the place again to point out the various pre-
cautions to be observed in the employment of this method,
for which I must refer to my former communications.

In’ conclusion, I give a tabular summary of the various
possible modes in which the light and dark may be disposed
in objects illuminated obliquely.

WELCKER, ON MICROSCOPIC DIAGNOSIS.

ou
Oo

I. Observation by direct light.

Object.

(a) Convex, opaque; e.g.| Shadowonthe sideturned

Opaque, erect papillze

(4) Convex, transparent ;
e.g. a starch-gra-
nule

(c) Hollow on an opaque | Shadow onthe sideturned

object
(d) Hollowona transpa-
rent object

Simple Microscope.

Compound Microsccpe.

from the light
Dark on the side turned
towards the light

towards the light
Dark on the side turned
from the light

Shadowonthe sideturned
towards the light.

Dark on the side turned
from the light.

Shadow onthe sideturned
from the light.

Dark on the side turned
towards the light.

II. Observation by transmitted light.

Object.

Simple Microscope.

Compound Microscope.

(a) Convex, transparent| Dark on the side turned! Dark on the side turned

towards the light

from the light.

(4) Depressed, transpa-| Dark on the side turned | Dark on the side turned

rent

from the light

towards the light.

36

REVIEW.

The Nature-printed British Sea-Weeds ; a history accompanied
by figures and dissections of the Alg@e of the British Isles.
By Wittram Grosart Jounstone, F.B.S.E., and ALEx-
ANDER Croatt, A.B.S.E. Nature-printed by Henry
Brapspury. Vol. I. Rhodospermee, Fam. I —IX.
London: Bradbury and Evans.

Tue success of the production of the British ferns by the
new process of nature-printing has encouraged Mr. Brad-
bury to attempt a much larger family of plants. The sea-
weeds, on account of their membranous nature, presented
peculiar facilities for representing them by nature-printing ;
and in this volume we have an instalment of a work which is
to be devoted to the whole of the British species of this
family.

The process of nature-printing, which has the power of re-
producing with great accuracy the outline and impressions
on the surface of plants, is effected by a kind of modelling.
The plant is first impressed upon a sheet of soft metal, and
from this a copper impression is taken by means of the
electrotype process. Into these copper plates the paper on
which the plants are produced is pressed, the plate having
been previously prepared with colour according to the colour
of the plant. This process, which is so well adapted to
secure the natural outline and superficial markings of plants,
cannot to any extent be employed in the reproduction of
minute points of structure, especially where this involves
anything more than can be obtained from a surface im-
pression. Under these circumstances, the authors in this
work have added to each plate drawings of the structure
and microscopic characters of the fruit of the various species
of algee represented in the plates. It is this part of the
work that will be found more espccially interesting to the
microscopic observer. Every species of sea-weed has its

JOHNSTONE, ON BRETISH SKA-WEEDS. 57

own peculiar power of reproductive organs, and few objects
are more beautiful and more interesting subjects of micro-
scopic research at the seaside than these organs amongst
the alge.

The present volume is only one of four which it is in-
tended to devote to the whole of the British Alge. It con-
tains sixty-six plates, and embraces only a part of the
Rhodcspermee, the remainder of which will appear in the
second volume. The families illustrated in this volume are
Rhodomelacee, Lamenariacee, Corallinacee, Spherococcoidee,
Gelidiacee, Spongiocarpee, Squamariee, Helminthocladiee,
Wrangeliacee. These families are embraced under the divi-
sion Desmiospermez, a group in which the spore-bearing
nucleus consists of tufted spore-threads attached to a cellular
placenta. The spores are formed singly, one in each cell of
the spore-thread, or only one in a terminal cell.

Many of the species illustrated in this volume are amongst
the most elegant and fragile of the alge. We can, however,
from a comparison of tliem with recent specimens at the
sea-side, speak of them as exceedingly accurate in their
forms, and very close to nature in their colours. There is
one group, however, which seems to have defied the nature-
printing process, and that is certain forms of the Corallinacee.
These plants creep along over stones and rocks, something
in the same way as lichens; and as they cannot be removed
without damage from the objects on which they grow, of
course nothing was left but to give coloured drawings or
engravings of them. This has been done with the genus
Meloseira, embracing the various forms of crustaceous alge
known by the name of Nullipores. These plants, which
were at one time regarded as zoophytes, and even described
by the late Dr. Johnstone with sponges, have a great interest
for the physiologist, as indicative of the earliest struggle of
organic forces with the chemical laws of nature. They still
present an interestingsubject for study, although their vegetable
nature has been well made out, and the arrangement of their
reproductive tissues is found to resemble closely many of
_ the higher forms of the red sea-weeds (Rhodospermee).

Although this work is evidently intended for the botanical
student already acquainted with the details of the structure
of the alge, we think it might be made amore widely in-
teresting work if it were accompanied by an introduction to
the study of the structure and functions of the alge. We
know that a good introduction already exists in Mr. Berkeley’s
admirable Introduction to the study of Cryptogamic Botany.
But this work embraces other things, and has been published

58 JOHNSTONE, ON BRITISH SI A-WEEDS.

now several years, and we should be glad to find the authors
of the present volume undertaking such an introduction—a
work for which they are evidently most competent.

The work is very properly dedicated to the memory of the
late Mrs. Griffiths, of Torquay. She was not only a brilliant
example of what her sex may do for the advancement of
science, but her many discoveries of species, and devotion to
scientific pursuits, entitle her to the gratitude and respect of
all who are interested in the progress of natural history
studies.

The description of the plants which accompany the plates
appear to us to be drawn up with care. Of course, exten-
sive use has been made of the works of Dr. Harvey, of
Dublin, to whom algology is so largely indebted. The
authors seem, however, to have had extensive communication
with those best acquainted with British alge, and their re-
ferences to habitats are extensive. The synonymy is also
carefully given, and references made to the works of authors
who have written on the subject of algology. We have
great pleasure in strongly recommending this work to the
attention of all who are interested in the study of the vege-
tation of the seas of Great Britain.

59

NOTES AND CORRESPONDENCE.

>

Cristatella Mucedo.—Where to look for and how to find this
Polyzoon.— Having lately (July 6th) obtained a number of
specimens of this beautiful Polyzoon, after very many in-
effectual but most diligent searches, in a large canal
reservoir, where I had frequently found the characteristic
statoblasts in the greatest profusion, I beg to offer a few
suggestions in the hopes of enabling all those who love a
microscopic treat, to hunt successfully for this exquisite
treasure.

Where to look? then, is the first question. ‘In clear
ponds and lakes,’”’ as Professor Allman tells us. The localities
in which I have found either the mature animal or the
statoblasts are the following :—1. A mill-pond on the Elmdon
road, belonging to Mr. Allston, about two miles from
Solihull. 2. A large canal-reservoir on the Warwick and
Birmingham road. 3. A pool of water in the grounds of
the Earl of Shrewsbury, at Alton Towers. I was rather
surprised to find the statoblasts here, inasmuch as the
water is decidedly somewhat muddy. Now, I am inclined
to believe that Cristatella is as frequently to be met with
as many other of the fresh-water Polyzoa— Alcyonella,
Fredericella, and some of the Plumatellide, for instance;
but while in these cases an upturned stone, or the under
side of a submerged branch or leaf, at once reveals the pre-
sence of the adherent Polyzoa—for the sponge-like masses of
Alcyonella, and the interlacing or branching tubes of the
Plumatellide, are evident to the eye, without the slghtest
effort; it is not by any means so easy a matter to detect the
presence of Cristatella, whose light-yellow ccencecium can
only with much difficulty and continued straining of the
eyes be seen, as the little colony rests upon some sub-
merged weed or stone, which weeds at this time of the year -
are sure to be overspread with scum, Diatomacee, and the
faded filaments of some Alge, of the same colour as the
animal.

Every lake, then, or mill-pond, or reservoir of clear water,
may be suspected to contain these most exquisite of all
the Polyzoa; and as the statoblasts are more easily found
than the developed colony, I would advise the searcher to
look for them in the autumn and winter and spring, as he

60 MEMORANDA.

will then have the satisfaction of knowing that there do
exist, in the pond he is searching in the summer, the mature
animals themselves. In order to obtain statoblasts, I would
say, look out for the sheltered spots in the pool, where are
collected all the floating rubbish, tangled masses of Alge,
decayed roots of grasses, feathers of birds, &c., &c. (it is a
curious fact that I have almost always found a quantity of
Cristatella statoblasts attached to feathers; so that I had
only to find these, and I was nearly sure to be rewarded
with a number of these little round membranous cases
agglomerated in one mass). Carefully examine the rubbish
bit by bit; in your hands if you like; but the best way is to
separate and thin out the rubbish in the water, when the
statoblasts will readily show themselves as dull masses,
sometimes nearly an inch long. The isolated individuals
are not to be depended upon as a rule, if you wish to watch
the germination; for they are generally only the separated
faces of old specimens. I have taken home frozen-up lumps
of rubbish, and have from these obtained statoblasts which
have duly germinated, though I have never been able to keep
the young polypes alive more than a few weeks.

But if the fully developed colony is the object of your search,
then in the months of July and August, and even in June
if the weather has been warm, visit the pond wherein the pre-
viously discovered statoblasts had shown evidence your ma-
tured treasure would be, and be not content with merely
stooping down, and pulling out the weeds of Ranunculus aqua-
trilis andthe Potamogetons, and examining them in your hands
out of the water, for such a search will most probably prove an
ineffectual one—it being almost impossible, amid the con-
fervoid growth which covers the plants, to detect the col-
lapsed form of your much-prized Cristatella; but you had
better lie flat down at once on the edge of the bank (the
-Polyzoa are almost always within a few feet of the bank,
covered by water varying from an inch in depth to about
two feet), flat down in ventrem, with your eyes close to the
surface of the water—then, with as little disturbance of the
water as possible, gently with your hand clear away the
floating weeds, and examine every submerged plant in sidu,
just as it grows in the water, with much patience. Probably,
for a minute or two, you will see nothing like a Cristatella ;
but be patient, continue to gaze, and you will be rewarded
most likely by observing, amid the scum and conferve, an
oblong-shaped feathery object, about an inch long perhaps,
of a pale-yellow colour, bearing a strong resemblance to the
well-known gelatinous egg nidamenta of Limneus stagnalis

MEMORANDA. 61

—only this is transparent, while Cristatella is, as I said,
feathery-looking, like, as M. Gervais has observed, bits of
Chenille—it is impossible, I think, to find a more apt simili-
tude. And now that you have once seen one specimen, you
will have little difficulty in being able to discover any amount
of others.

The extreme beauty of this Polyzoon, the fact of its con-
tinuing in an exserted state, even under rough treatment,
the transparency of the coencecium rendering an anatomical
examination so easy and satisfactory, must always make
Cristatella a great favorite, and one of the most prized and
beautiful of all the beautiful forms of aquatic life—Hoveuton.

Angle of Aperture. — Observing in the ‘ Microscopical
Journal’ of July last, an article on the measurement of
angular aperture of lenses from the pen of P. Gray, Esgq.,
and deeming its recommendations based upon determining
these observations irrespective of any special apparatus, thus
seemingly presenting facilities to individuals who may neither
have such in possession, or ready access thereto, I have ex-
amined the practical merits of the method in question, in
contrast with the known angular aperture of lenses in my
possession determined by other means, as No. 1 = 25°;
Woo NO. 3 —— Ol = No. 4, = 129°; the following
results being ‘obtained, exercising all ordinary care.

Nos

Decimal Number. Logarithm. Tangent.

Lights apart 7 inches : i ;
Distance of lens 16°75 X2 or sa pee

Angle of aperture 23:38
Another experiment gave 26°14

No. 2.
: : Decimal Number. Logarithm. Tangent.
Tights apart = _-15"50 inches _ 6739 «= «828595 or 38°58
Distance of lens 23 x2

Angle of aperture 67°56

The results by this lens were very variable, though not so
by the usual several feet radius.

No. 3.
Decimal Number. ithm. gent.
Lights apart 30°5 inches clarence es ak rp or ee
Distance of lens 144x2 9

Angle of aperture 87:06
Two other experiments gave similar results ; one gave 90°.

62 MEMORANDA.

No. 4.

The rule presented gave no provision for angles exceeding
90°; wherefore the supplement of the bi-tangent is used
through previous knowledge of that required.

Decimal No. Logarithm. Tangent.

Lights apart 44 inches 4545 = 657534 or 24°26
Distance of lens 10 x 2 «x2
Rule ends = 48°52
180—

Angle of aperture 131-08 supplement.
Another experiment gave 131-06
Ditto ditto 12624

Howsoever in theory the proposed plan may be, I am
satisfied that even with common care the results in practice
must prove very variable, and amounting, in some instances,
to differences of four or five degrees; thus not gaining much
upon the quantities ordinarily published by the: makers of
objectives —Witiiam Henpry, Surgeon, Hull.

Diatom-Finder.—I have had a simple little instrument
made for me by Messrs. Field and Co., that answers my
fullest expectation as a diatom-finder. It consists of the
tube of their Arts Society’s microscope, six inches in length,
with the higher eye-piece fitting into one end, and an object-
glass giving 180 and 130 diameters, into the other (the
screw also takes Powell and Lealand’s object-glasses). This
compound body slides into another tube about two inches
short, and is checked by a flange from going too far. On
the end of this second tube is cemented a thin disc of glass,
and over it fits a cap withathicker disc, forming an ordinary
animalcule-cage. When used you remove the cap, place a
drop of the fluid to be examined on the end of the tube, re-
place the cap so as to flatten out the drop, and hold the body
up to the light, adjusting the focus. The contents of the
drop by their own gravity may be made to’cross and recross
the field, simply by moving the body in the hand. The
whole fits into a little telescope-case an inch in diameter.
—Roserr Taytor.

PROCEEDINGS OF SOCIETIES.

June 29th, 1859.
Dr. LankestTeER, President, in the chair.

Henry Judd, Esq., Alfred Canton, Esq., Dr. Prendergast,
Henry Yool, Esq. «> EL. A. -Salver, Hsq., 8: C. Anderson, Esq.,
and the Duke of Manchester were balloted for, and duly
elected members of the Society.

A paper “On a Section and a Mounting Instrument,” by
Mr. James Smith, was read (p. 1).

A paper by G. F. Pollock, Esq., ‘On Granulated Blood-
discs,” was read (p. 4).

The meetings of the Society were then adjourned until
October next.

The following publications, &c., have been presented to

the Microscopical Society since the publication of the last
Journal.

March 31st, 1859.

Presented Ly
Observations on the Genus Unio. By Isaac Lea The Author.
Description of Twenty-seven New Species of Uniones.
By Isaac Tea Ditto.

Journal of the Geological Society, Vol. XV, Part 1
Address of the President of the Geological pecieas

Major-General Portlock : Ditto.
Linnean Society. Supplement to Botany, No.1 . Ditto.
Proceedings of the Academy of Natural Sciences of

Philadelphia. Several Parts . Ditto.

April.—No Meeting.
May 25th.

Musci Alleghanienses sive Spicilegi Muscorum atque
Hepaticarum quos in itinere a Marylandia usque ad
Georgiam. By W.S. Sullivant. 2 vols. 1845 . The Author.

The Mosses of the United States. By W.S. Sullivant.

1856 *. Ditto.
Contributions to the ‘Bryology ‘and Hepaticolozy of

North America. Two Parts. 1849. By Was:

Sullivant . Ditto.
Report on the Botany of the Expedition for a Rail-

road Route from the Mississippi River to the Pacific

Ocean. By W.S. Suilivant. 1856 Ditto.
Notices of some New Species of Mosses from the

Pacific Islands. By W. S. Sullivant. 1856 Ditto.
Musci Boreali Americani quorum specimina exsiccata.

By W. S. Sullivant-et L. Lesquereux. 1856 The Authors.

The Society.

64 PROCEEDINGS OF SOCIETIES.

Presented by

On the Measurement of the Strie of Diatoms. By :

W.S. Sullivant and 'T.G. Wormley. Also ‘I'wenty-

four Slides of Diatoms with the above. The Authors.
The Proceedings of the Academy of Natural Sciences

of Philadelphia. 1857 : . The Society.
The Ohio Agric. Report. 1856 ‘ . Ditto.

June 29th.

Quarterly Journal of the Geological Society, Vol. II,

Part 2 |. . Ditto.
The Journal of the Royal Dublin oats Nos. 12,13 Ditto.
The Photographic Journal, No. 85 Ditto.
The List of the Linnean Society. 1858 . . Ditto.
Journal of the Proceedings of the Linnean Society.

Supplement to Botany, No. 2 Ditto.
Journal of the Proceedings of the Linnean Society,

Vol. II, No. 12. Ditto.

Transactions of the Linnean Society, Vol. XXII, Part 3 Ditto.
Nine Photographs of various Microscopie Objects.
By M.S. Legg, Esq. ; 5 . M.S. Legg, Esq.
June to October.

Thoughts on Animalcules ; or, a Glimpse of the In-
visible World revealed by the a opel By G.

A. Mautell. 1846 F.C. 8. Roper, Esq.
Das Mikroskop. Von P. Harting. 1859. Ditto.
Some Observations on the Diatomacez of the Thames.

By F.C.S. Roper. 1854 . The Author.

Notes on some New Species and Var ieties of British

Marine Diatomacee. By F.C. S. Roper. 1857 . Ditto.
On the Genus Bicdulp'iia and its Affinities. ae ss Os

S. Roper. 1658 : . Ditto.

The following have been taken in exchange for sets of the
original Transactions and back numbers of the Journal.

EXCHANGES.

Construction of Timber from its earliest Growths, explained by the Mi-
croscope. By J. M.D. Hiil. 1724.

Dr. Hassall’s British Fresh-water Alge, 2 vols. 1845.

Kolliker’s Manual of Human Histology, 2 vols. Sydenham Society,
1852-54.

Wedl’s Pathological Histology. Sydenham Society. 1854-55.

Recherches Chimiques et Microscopiques sur les Conferves, Bisses, Tre-
melles, &c. Par Girod-Chantrans. 1802.

Cours de Microscopie complémentaire des études médicales Anatomie
microscopique et Physiologie des Fluides de l’economie. Par Al. Donné.
1844.

Traité anatomique de la Chenille. Par P. Lyonet. 1762.

Species Algarum. Par F. I. Kiitzing. 1849.

PURCHASES.

A Handbook of the Microscope. By W.L Notcutt. 1859.
Dr. Pereira’s Lectures on Polarised Light. 1854.

The Microscope. By Dr. Lardner. 1856.

Professor Quekett’s Lectures on Histology. 1854.

ORIGINAL COMMUNICATIONS.

Osservations on the Structure of Nerve-Fipre.
By J. Locxuarr Crark, Esq., F.R.S.

WHENEVER we wish to ascertain the natural appearance
and structure of the nerve-cells and nerve-fibres, these tissues
should be examined in some transparent part during life, or
on removal immediately after death, and with the addition
only of a little serum of the blood. But when it is intended
to investigate, in the nervous centres of the vertebrata, the
mutual relation of these elementary parts, and their natural
arrangement, such as the grouping of the cells and the course
of the fibres, it becomes necessary to harden the nerve-
substance in some kind of fluid, so that it may be cut into
thin sections, which can then be rendered more transparent
by a further process. The method which I extensively em-
ploy for such investigations is as follows:

The part intended for examination should be as fresh as
possible, and cut into pieces as small as compatible with the
particular end in view. ‘These pieces I formerly hardened
by means of a mixture of one part of spirit of wine and three
parts of water, which, at the end of twenty-four hours, was
replaced by a fresh mixture of equal parts of spirit and water,
and this again, after the same interval, by pure spirit, which
ought to be renewed every five or six days. But for the last
three years 1 have used chromic acid instead of spirit,
in the process of hardening. ‘The spinal cord of man, of
the Ox, Sheep, and other large vertebrata, is steeped in a so-
lution of one part of crystallized chromic acid in two hundred
parts of water, for two or three weeks, and then placed in a
solution of one part of dichromate of potash in one or two
hundred parts of water. For the hemispheres and the

VOL. VIII. F

66 CLARKE, ON NERVE-FIBRE.

cerebrum and cerebellum, and for the spinal cord of Rodentia,
Reptiles, and Fishes, the solution must be three or four times
weaker. Spirit is used to wet the knife in making the sec-
tions, which are placed in spirit for a few minutes, and then,
if thin, floated on the surface of spirit of turpentine. Here
they remain until they are quite or nearly transparent, when
they are removed to glass slides, on which a little Canada
balsam has been previously dropped. If now examined under
the microscope, they frequently show but little traces of cells
or fibres ; but if they be set aside for a time, and treated occa-
sionally with a little turpentine and Canada balsam, the cells
and fibres will reappear, and present a very beautiful ap-
pearance. Before they are finally covered with thin glass,
they should be examined at intervals under moderately high
powers. If the sections be thick, I find it best to place them
in a shallow vessel simply wet with turpentine, which can
therefore ascend from below, while the alcohol evaporates from
the upper surface ; for the principle of the method is this,—to
replace the spirit by turpentine, and this by Canada balsam,
without drying the sections. The method at first presents
some difficulties, and practice is necessary for complete suc-
cess; but when properly conducted, it affords many great
advantages, which no other method that I am acquainted
with can supply.* Not that I wish to imply that this, unhke
every other method, is in every respect perfect ; nor do I
always confine myself exclusively to its use; for whenever I
find that chromic acid, alone, offers greater advantages on
any particular point, I avail myself of it; as I do of any
other means that appear most suitable for the occasion.
Sometimes I find it useful to colour the sections, according
to Gerlach’s plan, before they undergo the process already
described, but I think it rather interferes with sharpness of
the fibres. The sections should be washed free from the
spirit employed in cutting them, and then immersed for a
few hours in an ammoniated solution of carmine of a deep
rose-colour, and previously filtered through paper ; for, with-
out these precautions, a deposit or crust is apt to form on
the object, in consequence of the precipitation of the carmine ;
and for the same reason the section, on being removed from
the carmine, should be again washed in water before bemg
placed in spirit, and then in turpentine.

Such were the carmine-coloured preparations which Messrs.

* This method of rendering sections transparent has been adopted in
Austria by Lenhossék (with some slight modification) ; by Gerlach, in Ger-
many; and quite recently, by Schroeder van der Kolk, in Holland.

CLARKE, ON NERVE-FIBRE. 67

Lister and Turner inspected, and made the subject of com-
ment in the last number of this journal. It is true, that in
the transverse sections the spiral arrangement around the
axis-cylinders is frequently, but not always, very faint, in
consequence, I think, of the aqueous solution of carmine in
which they are immersed, and which probably allows the
turpentine to have a greater influence on the white substance ;
for in the wn-coloured preparations, when properly made, the
spirals, or concentric circles, are most distinctly marked, and
their outlines, as well as the intervening connective tissue,
are more sharply defined than in any sections of the medulla
simply hardened in chromic acid. Preparations of this kind
are in the possession of several eminent physiologists, amongst
whom I may mention Professor Hughes Bennett, of Edin-
burgh; so that Messrs. Lister and Turner will have the
opportunity of mspecting them. While the white substance
of Schwann, however, is thus distinctly observable in trans-
verse sections, it is often but faintly seen, and sometimes
invisible, in longitudinal sections, unless the medulla be
hardened in a peculiar way, by first using a weak, and then
a very strong solution of chromic acid. But even the total
loss of this substance would be of little or no importance in
tracing the course of the fibres and their relation to other
tissues, for their axis-cylinders are rendered more than
naturally conspicuous and strong; while their sharpness of
outline, the fine definition of the other tissues under high
powers, and the advantage of examining them in sections of
amazing thickness, fully compensate for a loss which may
easily be supplied, when necessary, by some other mode of
preparation. But, as already stated, whenever we wish to
ascertain the natural appearance and structure of the nerve-
tissues, we must abstain from all kind of preparation. Before
I proceed further, however, I will briefiy explain the doc-
trines of Stilling on the structure of nerve-fibre.

In 1855, Stilling announced to the Academy of Sciences of
Paris, as the results of his inquiries, that the whole of the
primitive nerve-fibre—the membranous sheath, the white
substance of Schwann, and the axis-cylinder—are composed
of a continuous network of similar “ elementary tubules.’”’*

* *Comptes Rendus.’ He also states that the finest branches into which
the processes of the nerve-cells divide, resemble the “ elementary tubules”
of the primitive fibres, and that the cells are connected with each
other by their processes (p. 899). In the same volume (p. 956), M.
Gratiolet informs the Academy that he described this anastomosis of the
cell-processes as early as 1852. M. Gratiolet was evidently not aware

68 CLARKE, ON NERVE-FIBRE.

In 1856, the detailed inquiries were published in a quarto
volume, and illustrated by figures. The doctrines, though
not refuted, were received with hesitation on the Continent.
Kolliker speaks with caution on the subject. He says that
neither Stillmg’s nor his own preparations have convinced
him that the parts described and represented are tubular
elements. But while he refuses to accept the “ questionable
structure’ as a normal part of the nerve-fibre, he does not
thereby wish to stop any further inquiry, and adds, that
when we consider the researches of Schultze on the olfactory
nerve, and those of Remak, Leydig, and Hiackel on the
nerves of the invertebrata—researches which tend to show
that the contents of the nerve-tubes either wholly or partially
consist of fine fibres—we must be cautious in judging of state-
ments like those of Stillmg.* Mr. Lister attempts to account
for this fibroid arrangement by supposing it to arise from
the crystallization of the fatty constituents of the white sub-
stance during the process of hardening; but to me it does
not appear to resemble anything of this description; for in
form it frequently presents the appearance of a skein of
thread more or less loosely tangled ; whereas, in the crystalli-
zation of fatty substance, the fibres, however branched they
may be, are not twisted and curled in different directions,
but radiate in comparatively straight lines from a common
centre.

For two years after the publication of the work already
mentioned, Stilling had his attention constantly directed to
these nerve-fibres, while engaged in his recent work, in
which we find him reproducing with the greatest confidence
the same doctrines of nerve-structure, and devoting to their
illustration an entire folio plate, contaiming no less than
fifty-one figures, beautifully executed, and representing the
appearances in question with the greatest accuracy. But
before I proceed to the true explanation of these appear-
ances, it will be better to give a little more particular account
of Stilling’s latest descriptions, so that they may be more
clearly seen to admit of this explanation.-

1. The nerve-sheath consists of a thick network of the
finest tubules or fibres, which cross each other, communi-
cate, and take the most varied direction. From this thick
network the fibres run—many of them separately—both

that two years earlier (1850) this anastomosis was described by myself, who,
so far as | can find, was the first to announce the fact. (‘ Philosophical
Transactions,’ 1851, part, ii, p. 614.)

* *Gewebelehre” Dritte Auflage, 1859, p. 277.

CLARKE, ON NERVE-FIBRE. 69.

inwards and outwards. Those which run outwards become
connected with the sheaths of the neighbouring nerve-fibres ;
while those running inwards come into connexion with the
medullary sheath (white substance of Schwann) and the
axis-cylinder.

2. The white substance of Schwann consists of a number-
less multitude of the finest fibres, which take the most
varied course, but run mostly in oblique or in transverse
directions, and establish a communication between the
external sheath and the axis-cylinder.

3. The axis-cylinder consists of three layers, one within
the other, each of which sends out, in horizontal and oblique
directions, numberless ramifications, which cross the space,
and so constitute the fibres of the white substance, and
come into connexion with the so-called (external) sheath.
Whether the inner or central portion of the axis-cylinder is
hollow, or composed of the finest fibrils, is uncertain, but the
latter is more probable.

Besides the parts just described, each primitive nerve-fibre
contains an oleagimous fluid, which hitherto was considered
to be included between the external sheath and the axis-
cylinder, as in a hollow space or vessel. But this fluid is,
in all probability, contained in the finest tubules of the white
substance, as well as in those of the axis-cylimder and the
sheath.*

The “elementary tubules” of which each primitive nerve-
fibre is said to be composed are exceedingly small, varying
from the 745th to the 355th of a line in diameter.

Now it would be very difficult to account for the produc-
tion of such elementary fibres as these under the influence
of chromic acid, however disinclined we might be to acknow-
ledge them as parts of the normal structure, until further
proofs were adduced; and therefore, if we really admit
their existence—whether they be tubules or only simple
fibres,—and consider, atthe same time, the prolonged attention
of Stilling to the subject, as well as the facts brought to light
by Remak and others, we ought, I think, with Kolhker, to
be cautious in pronouncing a decided judgment. But the
question may be completely set at rest, for, as will presently
be seen, these supposed elementary tubules, or fibres, have
no actual existence whatever,—the appearances from which
they have been inferred resulting solely from corrugations,
ridges, or folds produced in the white substance by the
action of the chromic acid.

* ‘Neue Untersuch.,’ 4te Lieferung, p. 708.
VOL, VIII. G

70 CLARKE, ON NERVE-FIBRE.

The medullary sheath, or white semi-fluid, is semi-fiuid
and exceedingly pellucid, of great refrangibility, extremely
extensible, but inelastic, and of a peculiarly viscid nature, so
that when its continuity is interrupted, or whenever it is in
any way disturbed, it has little or no tendency to return to
its original position; and, like other semi-fluid and viscid
substances, may be drawn into fibres or into delicate expan-
sions of extreme tenuity. In its natural position around the
axis-cylinder (PI. IV, fig. a), its outer and inner surfaces (4, ¢),
where they are seen side by side at the lateral parts of the
fibre, give rise respectively to the outer and mner contour or
line; but if it constituted the entire fibre, instead of only a
layer around the axis-cylinder (a), it is evident that it would
be bounded only by a single, outer contour, or dark line, on
each side. Now a fold or ridge (fig. 1) raised up from the
white substance presents to an eye looking down on its
convex surface the same appearance as such a fibre would
present; that is, it appears as a fine tubule or fibre bounded
on each side by a single dark outline. When I directed my
attention to nerves hardened in chromic acid, with the
special view of ascertaining the cause of the fibroid appear-
ance, I soon became convinced, from many reasons, that
these so-called fibres are produced in the way I have just
stated. The first peculiarity likely to strike an observer is
the unnatural thickness of the layer of white substance, and
consequently of the entire fibre (fig. 2). This increase in
diameter would of course be attributed by Stillmg to the
separation from each other of the so-called “ elementary
tubules,’ which on that account have a more striking
resemblance, at first sight, to actual fibres. But if these
were really fibres, there would be vacant spaces between
them, whereas they are all connected together by inter-
vening portions of the hardened and brittle, but extremely
transparent white substance. Nothing at first sight can
look more like fibres or tubules than the loops at a a, fig. 2;
and yet, on closer examination, they were found to be only
the rounded borders of portions of the white substance pro-
jecting from the surface; for they imclose a transparent
layer which connects their edges with the rest of the primi-
tive-fibre. On the opposite side, at 6, is seen what might
easily be mistaken for a broken fibre; but it is nothing more
than the broken edge of a projection similar to those at a a,
with a transparent and almost imperceptible layer of white
substance connecting it with the general surface. In fig. 3,
at a, the same appearance is still more satisfactorily ex-
plained ; for here a piece of the rounded border of the pro-

CLARKE, ON NERVE-FIBRE. 71

trusion, with part of the transparent interior, has been
broken off. It will be understood, then, that all the folds,
ridges, or apparent elementary fibres represented in fig. 2,
are connected together by an intervening layer of the white
substance, which has a convex, concave, or some other kind
of plane, surface. Sometimes the surface of a primitive-
fibre, hardened in chromic acid, resembles a piece of parch-
ment crumpled into a multitude of folds of different shapes
and lengths, and loosely arranged around a central axis; and
sometimes it presents very much the same appearance, and
is indeed in the same condition, as the fissured bark of an
old tree, or the shrivelled bark of a young twig torn while
green from the parent stem. At the upper and broken end
of fig. 2 the superficial parts of the folds or ridges have
been brushed away, but the sharp edges of their bases may
be distinctly seen. Fig. 3 represents a primitive-fibre
deprived, in the same way, of the superficial parts of the
folds, except at a; but the sharp and fractured edges of the
subjacent substance from which they have been swept are
very conspicuous, and have, in one place, a kind of spiral or
concentric arrangement around the axis-cylinder, which axis
is probably the cause that determines such an arrangement,
under the corrugating influence of chromic acid. Figs. 4
and 5 represent two detached pieces brushed from the
surface of a primitive-fibre. In both, the apparent ele-
mentary tubules or fibrils are connected by a thin layer of
white substance ; and in fig. 5, where this substance is bent
in different planes, it is evident that every angular deviation
from the plane surface gives rise to the appearance of tubule
or fine fibre.

Although quite satisfied with the above explanation of the
appearances in question, I thought that if similar or nearly
similar results could be produced in the fresh nerve-fibre by
simple mechanical disturbance or manipulation, and without
the use of any chemical agency, the facts would be un-
deniably established. For the purpose of this inquiry, I
examined on several occasions under the microscope some
spinal nerves of the ox and of other animals, immediately
after death, and moistened only with fresh serum of the
blood. The primitive-fibres, when uninjured, had the well-
known semblance of translucent tubes with double contours
(as shown in fig. 6); and no traces of finer elementary
tubules or fibrils could be discovered in them, even under
high magnifying powers. But when the bundles of nerves
were torn asunder, and finely separated by means of needles,
the white substance assumed a great variety of appearances,

72 CLARKE, ON NERVE-FIBRE.

which were manifestly due to nothing but simple mechanical
disturbance. The injury was often limited to the sides of
the fibre, and consisted only of indentations or fissures,
which were sometimes plain and smooth, as in fig. 7, and
sometimes, as in fig. 8, more or less twisted into spiral
ridges, which had a considerable resemblance to fine ele-
mentary fibrils. The white substance between the two
contours, represented in fig. 9, had a completely spiral
arrangement, and might, if insufficiently examined, have
been compared to the fibres of a partially untwisted rope ;
but it evidently consisted of a continuous mass, in the same con-
dition as a twisted cylinder of glass, so that the appearance
of fibrils or tubules was caused by the prominent edges of
the spiral. Sometimes (as in figs. 10 to 15) two portions of
the white substance between the double contour was drawn
asunder to a variable distance, and in such a manner that
the intervening and viscid lamina, or expansion, was thrown
into a series of folds which might readily have been mis-
taken for tubules. But these ridges or folds (represented
by the light lines) were obviously continuous at their sides
with the pearly transparent substance in the spaces between
them. In fig. 16, a similar state of the fibre is very satis-
factorily seen ; for the lower portion (a) between the separa-
tion consists of fibre-like ridges, while the upper expansion
(4) is only slightly undulated.

When the nerve-fibre was stretched and dragged, or other-
wise rudely handled, the wrinkles and undulations were not
confined to its sides, but extended over its entire surface, as
represented in fig. 17. Sometimes they originated from
between the double contour, where the white substance was
frequently fissured or indented, and after a short but various
course, they flattened and subsided into the surrounding
surface, or intercommunicated as apparent fibres in a kind of
anastomosis. This last-mentioned appearance is remarkably
well seen in fig. 18. At the upper part of the fibre, on the
left side, the white substance was thrown into a convolution,
which gave it the appearance of having two double contours
at that spot. Lower down was a thick convex elevation or
fold, which stretched transversely across from one double
contour to the other; and on either side of this were nume-
rous smaller folds of precisely the same kind, and having a
remarkable similitude to anastomosing fibres. In some parts
(see fig. 19) the surface of the fibre consisted entirely of
large convolutions like those of the cerebral hemispheres ;
while in other parts, as in fig. 20, these convolutions sub-
divided into apparent fibres or tubules. Even when the

CLARKE, ON NERVE-FIBRE. 73

contents of the nerve-fibre were squeezed out, they assumed
the same diversity of form. Fig. 21 @ is a large globule
of white substance variously wrinkled ; in two other globules
(6 6) the surfaces have been thrown into a kind of network
of wrinkles or folds, like the surface of the fibre, fig. 18. In
the globule (c) the ridges have a spiral arrangement ; and at
d, a fold or ridge arising from the inner contour, has
exactly the appearance of a tubule or fine fibre ; but near the
centre of the globule, it subsides into the smooth convex
surface which surrounds it.*

After I had observed all these appearances as the effects of
manipulation, I carefully dissected another fresh nerve, and
having selected some uninjured primitive-fibres, like the one
represented in fig. 6, I introduced under the thin covering-
glass a little acetic acid, and watched the result. The imme-
diate effects were a multitude of very small depressions or
pits, which showed like the fine marks of a mezzotinto
engraving (see fig. 22). These were succeeded by deeper and
larger depressions prolonged in different directions, so that
the intervening elevations might have easily been mistaken
for tubules. Sometimes these ridges were more or less
longitudinal, but short, and resembled the elevations in the
fissured bark of a tree (see fig. 22). Sometimes they ran
transversely and obliquely, and joined in a complete network ;
or turned about in loops, or in spirals like the spirals seen at
the cut ends of fibres hardened in chromic acid (see figs. 22
and 23). It was evident that all these appearances were due
to the same state of the white substance as that which has
been shown to be produced by mere mechanical disturbance.

* Stilling maintains that in the /resh nerve-fibre, the inner, like the outer
contour, does not form a continuous or uninterrupted line, but splits in
various ways, and sends processes to the axis-cylinder ; and that under a low
power (his figures are magnified 1100 diameters) it seems to have a con-
tinuous boundary line only because the “ elementary tubules or fibres” pro-
ceeding from it cannot be seen on account of their extreme transparency in
the fresh state. ‘“ Wenn man aber bei starkeren Vergrésserungen sorefaltig
untersucht, so wird man finden, dass die innere Contour, eben so wie die
fiussere, nicht stets eine linienformige Begranzung bildet, sondern vielfach
unterbrochen ist, sich theilt, Fortsatze gegen den Axencylinder hin aus-
sendet, und nach kiirzerem Verlaufe in Continuitat abgebrochen anscheinend
aufhdrt, und dass sie nur deshalb den Auschein emer Begranzungslinie giebt,
weil die nach innen wie nach aussen auslaufenden Fasern oder Rohrehen,
wegen ihrer Durchsichtigkeit im frischen Zustande, nicht erkannt werden
kénnen.” (* Neue Untersuch.,’ 4te Lief., pp. 730-31.) These divisions of
the inner contour, as well as the processes or fibres which he believes it
sends to the axis-cylinder, are nothing more than the indentations, cor-
rugations, and folds shown in figs. 17 aud 18 to result from mere mecha-
nical injury.

74 CLARKE, ON NERVE-FIBRE.

With regard to the structure of the external or mem-
branous sheath of the primitive nerve-fibre, there is some
difference of opinion amongst anatomists. According to
Schwann, and Todd and Bowman, it is a structureless, homo-
eencous, and finely granular tissue; while Fontana, Valentin,
Remak, Henle, and others, have described it as composed of
fibres which cross each other in different directions. Ac-
cording to my own observations, it consists of fibres of
different shapes and sizes, but sometimes of such extreme
delicacy, that when in close apposition they appear to be
fused, as it were, into a homogeneous, finely granular, but
nucleated membrane. Some of these fibres are broad, flat or
riband-shaped, of a faint or shadow-like aspect, and spotted
at intervals with exceedingly pale and delicate granules ; they
are joined together at their edges and proceed from the whole
breadth of their nuclei, which are occasionally oval, but
generally very elongated and spotted with the same kind of
granules as the fibres; they are frequently found covering,
as with a continuous nucleated membrane, the entire surface
of many of the smaller primitive-tubules. Other fibres
composing the external sheath are of smaller diameter, but
sometimes less delicate and branched; they proceed from
the ends of their nuclei, which are also occasionally coarser
and of darker outline.

About two years back, while examining some sections of
the spinal cord of the Calf and of other young animals, pre-
pared according to my own method, I was surprised at
finding that the whole of the white columns were studded with
nucleated cells which adhered to the sheaths of the primitive-
fibres, and occupied the spaces between them. Now, there
is reason to believe that in the adult these ce//s become
developed into filamentous tissue; for in the ox and other
full-grown animals I found that the ced/s had disappeared,
but that their nuclei were still present between the primitive-
fibres.* In a short exposition which I gave, last summer, at
the University of Edinburgh, of some of the most important
points in the anatomy of the spinal cord, I alluded to the
presence of these nucleated cells in the white columns. It
appears, however, that Messrs. Lister and Turner were not

* For further information on this subject, see my late Researches, read
before the Royal Society in 1858, and published in the first part of the
‘ Philosophical Transactions’ for the present year. I may also take this
opportunity of calling attention to an Ouéline of the Anatomy of the Spinal
Cord, published in No. iii, 1858, of Beale’s ‘Archives of Medicine,’ and
written for the use of those who have not time for reading the more detailed
treatises.

ARCHER AND DIXON, ON DESMIDIACER. 75

able to find them or their nuclei in sections simply hardened
in chromie acid, but noticed occasional nuclei on the sheaths
of the fibres in the sciatic nerve. In most parts of the cord,
when simply hardened in chromic acid, it is certainly very
difficult to detect them ; for, being about the size of the cut
ends of the smaller fibres and blood-vessels, they are scarcely
distinguishable in the confused and badly defined matrix in
which they are imbedded. Stilling, even with a magnifying
power of 1100 diameters, has failed to detect these bodies
in the cord of the Calf. But in preparations made according
to my method they may be seen with the greatest facility
under a power of 400 diameters, in consequence of the
superior definition. Even with the simple use of chromic
acid, however, they may be very readily found towards the
lower end of the cord,—in the coccygeal region; for here
the white columns are very much subdivided by numerous
ramifying fissures containing pia mater and connective
tissue, in which the cells or their nuclei abound.

Description of Two New Srvsctres of Stavrastrem, by W.
Arcuer; @ New Genus and Sprrctiss of Drsmipiaces,
by the Rev. N. V. Dixon ; and some cases of ABNORMAL
Growtu of Desmipiacex, by W. ARcHER.

(Read before the Dublin Natural History Society, on Friday, June 3d,
1859; extracted from the ‘Natural History Review and Quarterly Journal
of Science,’ for Oct. 1859.)

In these days of cancelling from our lists, and their con-
solidation with others, of numerous species, or reputed species,
in the various walks of natural history,—and this, no doubt,
in many cases, with much reason,—it may appear unjustifiable
rashness and temerity on my part to come forward for the
purpose of describing the following two new forms to be added
to our lists of Desmidiaceze. But im a more extended point of
view, in regard to what is a species and what is not, it seems
to me that naturalists are prone to err in one of two direc-
tions: they either restrict the number of species in their lists
within too narrow limits, or imordinately imerease their
number by giving a name and specific rank to almost every
variation which they encounter. On the one hand, because,
between two hitherto recognised distinct, but allied species,

76 ARCHER AND DIXON, ON DESMIDIACE.

there are occasionally found forms, as it were intermediate,
connecting them, it 1s assumed that these two original forms
must necessarily make but one species. On the other hand,
those naturalists might possibly be not wanting who would
feel inclined to consider not only the two original, but also
one or several of those intermediate forms, as themselves
species. Both extremes, as it seems to me, may be wrong.
Might it not be expected to be the case that the limits of
variation of each of the two original species, so nearly allied,
might, so to speak, so touch each other at the margin, as to
seem to unite them together, and give rise to the assumption,
always plausible, but perhaps not always correct, that one of
the original species could (and does), by aseries of transitions,
pass into the other? If any one species become modified, is
it not to be expected that the characters of the most nearly
allied form, and not those of one remote in affinity, will be
those which, to a greater or less degree, it will be likely to
simulate? Under this hypothesis, the two original forms
would still justly be considered true and distinct species—in
contradiction to the opinion of the former class of naturalists
—while the forms intermediate would be but variations
(perhaps but of a temporary or local nature), some derived
from one species, some perhaps from the other, and could by
no means be looked upon as true species—in opposition to
the views of the latter class of naturalists. I do not mean to
intimate, when a hitherto acknowledged species is rejected,
that I imagine the step always to be an erroneous one, for he
who successfully demolishes the spurious claims of a mere
book-species does science a good service ; but it seems to me
that what I have tried to express is a state of things, the pos-
sibility of the existence of which, by those who are anxious to
suppress species, may sometimes be lost sight of or ignored.

There can be no doubt, however (and especially amongst
microscopic forms), that our lists are more or less encumbered
with the redundant names of false species, which further
research will doubtless eventually prove. Many forms which
now pass under distinct names may hereafter be found not
worthy to take specific rank in our systems. And here it is
that the difficulty hes. In order to prove the identity of two
reputed species, over which there hangs a doubt, not only
must the happy opportunity be afforded of tracing the or-
ganism through its whole course of life, but, on the part of
the observer, the requisite leisure and patient assiduity must
not be w anting.

No doubt it is much easier to describe a new species than to
demonstrate that two, or perhaps more, familiar forms are but

ARCHER AND DIXON, ON DESMIDIACER. 77

different states or phases of one and the same organism.
Nevertheless, when a form undescribed and quite distinct
from any of its nearest allies in the same genus, and distin-
guished by marks as decided and striking as those by which
species, which are universally acknowledged, are separated,
presents itself occasionally, perhaps abundantly, and which
may as hkely be met with by other observers, it seems to me
‘right, nay essential, that it should be distinguished by a
name, and its diagnostic characteristics carefully recorded.

I offer the foregomg remarks,-which it may be proper to
state were written considerably before the Hymenophyllum
discussion arose, as apologeticformy venturing to bring forward
the following description of two species of Staurastrum ; and
yet, perhaps, they are not strictly applicable, for these new
forms appear to me abundantly distinct from every other
species, and in no way to be mistaken for mere mtermediate
or gradational variations. 'To some, however, it may seem
premature to describe them without knowing the sporangial
state. It will be recollected, however, that, of very many of
the species, as described in Ralfs’ ‘ British Desmidiez,’ the
sporangium is not known, nor, when known, can there usually
be important distinctions drawn from it. I trust the follow-
ing may serve as a description of the new forms:

Family DesMipiacE&.
Genus Staurastrum, Meyen, Bréb., Ralfs, &ce.
Staurastrum oxyacantha (sp. nov.)

Specific characters: Frond rough with minute granules ;
segments broadly fusiform, with incurved processes ; end view
tri-radiate, each side having, disposed at equal distances, a
pair of depressed, slender, subulate, acute spines.

Locality: Pools near “ Sugar-loaf’ Mountain, on the
Roundwood road ; rare.

General description: Frond nearly as long as broad ; seg-
ments rough, with minute granules, broadly fusiform, inner
margin somewhat more turgid than the outer, and forming
at constriction a broadly triangular notch, tapering at each
side into a colourless process incurved or converging with
that of the opposite segment, having the granules theron
arranged in transverse lines, and cleft at the extremity ito
three or four minute subulate spmes; frond furnished at ends
upon each side with a pair of slender subulate, acute,
depressed spines, which are apparent in the front view. End

78 ARCHER AND DIXON, ON DESMIDIACER.

view tri-radiate, having projecting from each side at equal
intervals the parallel pair of spmes unaccompanied by others ;
processes terminating each angle in this view, straight, elon-
gate ; endrochrome restricted to the centre, triradiate.

Length of frond, 745 of an inch; breadth, =4, to ;1,;;
breadth of constriction z5,.

Plate VII. Fig. 1, front view; fig. 2, end view.

This form appears to me very distinct from any described.
The presence of the conspicuous pair of acute spines pro-
jecting from each margin at end view distinguishes it from
all but Staurastrum vestitum, but in that species the spines,
which are apparent only in the end view, are emarginate at
the ends, and often accompanied by others of considerable
size; and indeed, even the smaller are themselves often
emarginate ; moreover, in the front view it differs by its
converging process. It is also considerably smaller than
Staurastrum vestitum, bemg not more than half its width,
which diameter in that species greatly exceeds its length.
The conyerging processes in front view are somewhat like
those of S. cyrtocerum ; but in that species there are no spines
at the ends of the fronds, and the processes in end view are
not so much prolonged, and are curved in place of straight.
The presence of the marginal spines in end view, and the
incurved, not divergent, or parallel processes in the front view,
distinguish this from S. paradoxum, S. gracile, and S. poly-
morphum.

Staurastrum nitidum (sp. nov.)

Specific characters: Frond rough at the ends, with a series
of papilla-like granules ; segments broadly elliptic; end view
triangular; sides convex, with a submarginal series of
papillz ; angles not inflated, mucronate.

Locality : Pools near “ Sugar-loaf;” rare.

General description: Fronds about as broad as long; seg-
ments broadly elliptic, inner margin somewhat more turgid
than the outer, sub-mammillate at each side, terminated by a
mucro, and on the outer margin rough with a series of
minute papillae, otherwise smooth; constriction forming a
broad notch, with an acute angle ; end view triangular, sides
convex, with an inwardly curved sub-marginal series of
papillxe, their summits directed somewhat towards the angles ;
angles not inflated, the last papilla forming a terminal mucro ;
endochrome in both views disposed in a radiate manner ;
gelatinous investment evident.

ARCHER AND DIXON, ON DESMIDIACEA. 79

Length of frond, 34, to z4,; breadth of frond, ~1,;
breadth at constriction, 74,5 of an inch.

Plate VII. Fig. 3, front view; fig. 4, end view.

This, although not a complex form, owing to its brilliant
and beautifully radiately-disposed endochrome (in front view
almost in fillets), is an extremely pretty species. In end view
its non-inflated mucronate angles and series of papille dis-
tinguish it, I think, from every other Staurastrum. In
front view it somewhat resembles S. asperum, Bréb., a, but
the minute spines on the outer margin, in that species, are
usually emarginate or cleft at the ends, or dilated, and the
segments are not mucronate at each angle, nor is the endo-
chrome radiately disposed. In the form in question, the
convex sides, mucronate angles in end view, and granules
not scattered, distinguish it from S. punctulatum. I do not
think I need contrast it with any other species, and I believe
that both the foregoing forms have only to be seen, when
their perfect distinctness would be at once apparent.

New Genus and Sreciss in the DESMIDIACER.

I beg leave to submit to the notice of your Society the
following account of a form of Desmid, which I have lately
met with in this neighbourhood, and which I believe has not
hitherto been described. The frond, as represented in Plate
VII, figs. 5—7, is simple, compressed, with a deep and acute
gaping constriction between its segments, which are three-
lobed, the line separating the extreme from the basal lobes
being parallel to the line of separation of the segments. It
has no inflation on its surface, but exhibits on its margin a
few mucronate spines. This form appears to me to be gene-
rically distinct from both Micrasterias and Euastrum: from
the former in the direction of the separation of its lobes, from
the latter in the absence of inflations. In these characteristics
it agrees with Micrasterias oscitans and M. pinnatifida, Ralfs,
as well as with the form Holocystis oscitans, Hassall, de-
scribed by Dr. Hassall, and referred to by Mr. Ralfs (‘ Bri-
tish Desmidiex,’ pp. 69—77), and it is worth considering
whether these forms should not be all grouped together in a
new genus. Before proceeding, however, to give the com-
plete description of this proposed genus and the three species
which it would contain, I beg leave to offer a few remarks on
the different manner in which the segments are divided in
those Desmids which have lobed or divided segments, and

80 ARCHER AND DIXON, ON DESMIDIACER,

which for this reason I take the liberty of calling Schizomerous
Desmids.

The typical mode of division (as exemplified in Huastrum
pinnatum, E.. oblongum, &c.) appears to be into three portions
or subdivisions : the first, next the line of separation of the
segments, extending across the frond, and embracing the two
basal lobes; the second, including the median lobes; and
the third, the extreme or end lobe. This last, or third sub-
division, is the most constant. The two former are frequently
represented by a mere sinuosity or shallow indentation where
the third is distinctly developed, but we never find the first
subdivision distinct, and the second and third imperfectly
separated. The whole three, indeed, may be merely marked
by shght sinuosities, as in Huastrum cuneatum, but if any one
is separated, it is the third; and this, I may observe, is the
order of development of the subdivisions in the growing seg-
ment of the typical Micrasterias. The new segment is first
hemispherical ; the third subdivision is then developed ; and
afterwards the first and second are separated.

For the purposes of description these three subdivisions
might be denoted by the letters a, 6, ¢; and their partial or
complete development marked as follows :—When the subdi-
visions are distinctly separated, their symbols might be
separated by commas, thus, a, b,c; when any two or more
are merely marked by a sinuosity, they might be represented
thus, a ~6; and if there is no trace of separation, thus, ad ;
and if, at the same time, the direction of the lines separating
the subdivisions were noted, the full description as regards
the divisions of the segments would be given. Thus:

Euastrum cuneatum would be represented by a~~b~ce.
us pinnatum “ “s a, b, ce, parallel.
i oblongum M3 < a, 6, ce, subraidal
Micrasterias denticulata ,, a a, 6, ¢, radial
Luastrum pectinatum : 3 a~b, cc, parallel.
And our new form a 2, ab, c, parallel.

The direction of the lines of separation of the subdivisions in
the Schizomerous Desmids varies from parallelism to true
radiation, and at the same time the intervals between the
subdivisions close, so that in Micrasterias denticulata, rotata,
and fimbriata, the frond appears almost entire with radial
lines on its surface. I think regard ought to be had to this
characteristic in placing the genera and species of Euastrum
and Micrasterias between the filamentous forms on the one
hand and the Cosmaria on the other; that the forms with
parallel subdivisions should come first ; the Euastra, so well

ARCHER AND DIXON, ON DESMIDIACES. 81

marked by their peculiar inflations, a few of which are
parallel, but the majority subradial, next; and the Micras-
terias last, terminating with the radial closed species, from
which the transition would be easy to the Cosmaria, among
which traces of radiation still appear im the endochrome of
C. Ralfsii, in the ridged surface of C. undulatum, and the
crenated margin of other species. The whole group of
Schizomerous Desmids then might be distributed among
three genera—the first containing MW. oscitans, M. pinnatifida,
Ralfs, Holocystis oscitans, Hassall—if this be distinct from
M. oscitans, which appears doubtful—and our new form ; the
next being Euastrum, and the last Micrasterias. In conclu-
sion, I beg to mention that I owe the drawing which accom-
panies this paper to the kindness of Mr. Archer, whom I
consulted when I first met with the new form under discus-
sion, and to whom I forwarded the gathering in which it
occurred for further examination; and that the following
detailed generic and specific descriptions have been drawn up
by the same gentleman.

Family Dusmiviacez.
TETRACHASTRUM (gen. nov.)*

Generic characters: Frond simple, compressed, deeply
divided into two three-lobed segments; the basal lobes pro-
jecting horizontally, broadest within and attenuated outwards ;
end lobe expanded into two lateral attenuated projections
parallel in their direction with the basal lobes ; ends straight,
or convex, or having at the middle of the rounded ends a
very slight concavity.

General generic description: The fronds are simple, as
long as or longer than broad, compressed, without inflations,
deeply divided into two segments by a constriction, forming a
broad acute-angled notch; each segment constricted by a
broad notch or sinuosity upon each side into two subdivisions
forming three lobes, the basal lobes broadest within and
attenuated outwards, not radial, but extending horizontally

* From rérpaya, in four parts, in reference to the fourfold division of
the fronds, which is most conspicuous in 7. oscitans and 7. pinnatifidum, and
dorpov, a star. This latter term, in its usual sense of a radiate form, is
not a descriptive one, as applied to our new genus; but I adopt it because
it occurs in the names of the other two genera of the same group, and 1
wish to mark their mutual affinity. Moreover, the term dorpoy is not more
inapplicable, on this ground, to the fronds of the proposed genus than it is
to those of several species of Euastra,—Z. cuneatum, &c., for instance.—

R. V.D.

82 ARCHER AND DIXON, ON DESMIDIACEX.

and parallel in their direction with those of the opposite seg-
ment; the end lobe expanded laterally into two attenuated
projections, which are horizontally disposed, and parallel in
their direction with that of the basal lobes, so that the entire
frond is of a pimnatifid character; the ends of the fronds
convex, straight, or having at the middle a very slight con-
cavity or depression, not emarginate.

Tetrachastrum mucronatum (sp. nov.)

Specific characters: Frond longer than broad; ends
rounded, having a slight central concavity; end lobe having
its lateral projections terminated by a mucro; basal lobes
broadly and bluntly triangular, having at their magin at each
side either one, two, or three minute mucro-like spines ;
empty frond punctate, the puncta scattered.

Symbol: ad, ¢, parallel (vide supra).

Locality : Bog near Carrickmore, Co. Tyrone.

Measurement: Length of frond, ;3,; greatest width, 4; ;
width of neck, 54; ; diameter at constriction, s$>; greatest
depth, 3345 of an inch.

Plate VII.—Fig. 5, front view with endochrome ; fig. 6,
empty frond; fig. 7, outline of side view; fig. 8, outline
of transverse view.

General description: The frond in this species is large,
smooth, entire, about one fourth longer than broad; in the
front view divided into two segments by a deep constriction,
forming an acute-angled straight-sided notch, not linear, but
broadest at the outside. The segments are constricted about
two thirds of the way from the base by a rounded sinuosity,
causing the basal lobes to be of a bluntly triangular outline,
straight on the lower, turgid or convex on the upper margin,
and furnished thereon with one, two, or three minute mucro-
like spines, one always at each basal angle. The basal lobes
slope upwards to form a broad neck, wniting the terminal lobe
to the basal portion: supposing the end to be absent, the
frond would be orbicular. The lateral projections of the end
lobe have their extremities tipped by a mucro, and somewhat
projected downwards. Ends of the fronds conyex with a
gentle central concavity. In the side view the frond is
smooth, about four times longer than its greatest depth; the
central constriction is rather deep; the segments in this view
ovate, turgid near the constriction, somewhat tapered towards
the ends, which are rounded. ‘The transverse view is broadly
fusiform ; the endochrome rich green, with scattered granules.
The empty frond is punctate, the puncta scattered.

ARCHER AND DIXON, ON DESMIDIACEA. 83

By attention to the generic characters as given above, this
species can of course be readily distinguished from every other
Desmidian, Micrasterias oscitans, Ralfs, and M. pinnatifida,
Ralfs, excepted. The presence of the marginal mucronate
spines, and of those terminating the lateral projections of the
end lobe, combined with the absence of the incised extre-
mities, as well as the frond being longer than broad, at once
distinguish this from both those species, which, as a matter of
course, I here include in this genus. It may be advisable
here to transcribe from ‘The British Desmidiez’ (pages 76,
77) the specific characters of both those two species, the
first under the name of—

Tetrachastrum oscitans = Mic. oscitans, Ralfs, Holocystis
oscitans, Hassall.

“Frond with convex ends [segments constricted], lobes
[horizontal] conical, bidentate.”

The characters here placed between brackets become
generic by transferring this species to this new genus, but as
it was included in Micrasterias by Ralfs, they were necessarily
introduced as specific distinctions from the proper species of
that genus. From the remarks in the preceding part of this
paper on the new genus, it will, I hope, be admitted that
they are really generic. In order to distinguish this species
from Tetrachastrum mucronatum, they are not requisite, as
the bidentate extremities to the lobes, with the absence of
the mucros, and the frond being nearly about as broad as
long, readily do so.

The remaining species will be—

Tetrachastrum pinnatifidum = Micrasterias pinnatifida,
Ralfs.

“Frond plane, its ends straight [segments deeply con-
stricted], lobes [horizontal] triangular, bidentate.”

The same characters which distinguish the preceding species
from Tetrachastrum mucronatum also separate this, which is
moreover much smaller. It appears to differ from the pre-
ceding by its much smaller size, straight or slightly concave
ends, more tapering lobes, and paler colour.

There can be no doubt, it is imagined, that the view taken
above is correct in defining this genus as three-lobed, that is,
with two basal lobes and a laterally expanded terminal lobe,
and not four-lobed, that is, counting the lateral projections of
the end lobe as two, which would involve the necessity of

84 ARCHER AND DIXON, ON DESMIDIACE.

describing these forms as truncate, and without a terminal

lobe. The end lobe in these forms is equivalent to the same

portion in Micrasterias rotata, or M. Crux-Melitensis, and
differs by having its more extended lateral projections not
divergent, but, as above described, projecting horizontally and

. parallel in direction with the attenuated basal lobes.

The following synopsis of the Schizomerous Desmidian
genera, and of the species of Tetrachastrum, will, it is hoped,
assist I conveying, in a succinct manner, the views put
forward above, as well as the end sought to be accomplished
in the present paper by the institution of the genus.

Frond lenticular, as long as or longer
than broad ; segments usually semi-
orbicular, five- or rarely three-lobed
(with three, or rarely two subdivi-
sions, a, b, c, or a~~b, c); lobes
radiant, incised or dentate, rarely
only sinuate, widening outwards ;
central constriction usually linear.

Micrasterias.
(Vide ‘ Brit. Desmidiez,’ p. 68,
et seq.)

Frond longer than broad ; segments
more or less conical, five- or three-
lobed, or sinuated (with three or
two subdivisions, either a, b, c, or
a~~b, c, or ab, c, or rarely abe),
possessing variously disposed, cir-
cular, inflated prominences; ends
emarginate, or rarely with merely
a concavity; central constriction

Frond simple, com-
pressed, deeply con-
stricted, segments
lobed or sinuate
(Schizomerous) ;
lobes either incised,

sinuate, or entire. iste! Eugesiiee
(Vide ‘ Brit. Desmidiez,’ p. 78,
et seq.)

Frond about as long as or longer
than broad ; segments three-lobed
(with two subdivisions, ad, c),
without inflated prominences; basal
lobes horizontal, attenuated out-
wards, end lobe expanded laterally,
its lateral projections parallel in
direction with the basal lobes ;
ends straight or rounded, entire ;
central constriction forming an
acute-angled spreading notch :

ARCHER AND DIXON, ON DESMIDIACE, 85

Tetrachastrum.

Frond longer than broad; segments constricted about two-
thirds of the way from the base; lobes mucronate, their
extremities not bidentate. Mucronatum.

Frond as broad as or slightly broader than long; segments
constricted about half-way from the base; lobes not
mucronate, their extremities bidentate.

Frond with convex ends ; lobes conical; colour rich green.

Oscitans,
Frond with straight ends, plane; lobes triangular; colour
pale. Pinnatifidum.

Noricr of some Casrs of ABNoRMAL GrowtH in the
DeEsMIDIACES.

Ir has occurred to me that the accompanying sketches,
representing an abnormal mode of growth in the Desmidiaceze,
exhibiting, as they do, an appearance so curious and unusual,
might possess some interest for the students of that family.
I am aware that, in Mrs. Herbert Thomas’s interesting
communication (‘ Quarterly Journal of Microscopical Science,’
vol. ii, plate v, figs. 17 and 18), that lady has figured a
very similar case in Cosmarium margaritiferum to that shown
’ in my drawing of Staurastrum dejectum; yet I have thought
it might be worth while to figure some examples of the
phenomenon still farther carried out in other genera, al-
though it may he quite possible that even more curious
aberrations may have been met with by other observers.

The first case of this mode of malformation to which I
shall direct attention is a monstrosity of a variety of
Micrasterias Jenneri (Plate VII, fig. 9). Here the inter-
vening growth, produced after the mode which prevails in
the Desmidiacez, between the two older segments of the
original frond, and which, in the normal condition, ought to
have formed two new segments, forms a somewhat quadrate
expansion, but has not assumed any definite outline. We
find it within filled with endochrome, similar to the parent
segments, to about the dimensions of one of which it has
attamed. It is about the simplest form of the irregularity
under consideration which I have to bring forward; the
intervening new portion forming only an irregular, shapeless
growth.

I here wish to draw attention in passing to the form itself

VOL. VIII. H

86 ARCHER AND DIXON, ON DESMIDIACEX.

(fig. 9), a fair idea of which in the normal state can be
obtained by imagining the irregular central growth as absent,
and the two older segments in apposition. It will be seen
that this variety agrees with Micrasterias Jenneri, Ralfs,
variety 3, in the superficial granules being somewhat large,
giving a somewhat dentate or roughish appearance to the
margin, but it differs from both varieties, a and 8, by its
lateral lobes not beg bipartite, and of course wanting their
emarginate subdivisions. Thus, if Mr. Ralfs justly “called
this species, both a and £, puzzling, the drawing before us
exhibits a form even more so (vide ‘ British Desmidiex,’ p-
76). On account of the lobes not being incised, as just
pointed out, this form (of course I need not repeat that I
do not allude now to its abnormal irregularity) becomes, I
think, likely to be mistaken for an Euastrum, to which genus
it closely approaches through E. oblongum. Nor is the
resemblance lessened by there occurring occasionally speci-
mens with the incisions between the segments, not linear, and,
therefore, the lobes not closely approximate, but spreading
and sinuously lobed. However, the absence of any infla-
tions, when viewed laterally, as well as the want of a
terminal linear notch, though there is a slight concavity or
depression at the ends, whilst the lobes are cuneate and more
radiant, exclude this form from Euastrum. I would here
then, take the opportunity to characterize this plant thus :—

Micrasterias Jenneri, Ralfs, var. y.

Granules giving a rather rough appearance to the margin,
lateral lobes concave, not bipartite, without emarginate sub-
divisions.

Locality: Bog, near Carrickmore, county of Tyrone.
This very interesting variety occurred in the gathering kindly
forwarded to me by the Rev. R. V. Dixon, and which also
contained his new form, Tefrachastrum mucronatum.

In the monstrosity of Staurastrum dejectum, as shown in
the drawing (fig. 10), we have both the new segments well
developed, ‘and each possessing im the front view its own
proper laterally projecting spines; but the interposed seg-
ments remain confluent throughout a portion of their ter-
minal margins, forming a bluntly triangular notch at the
sides, the whole making but one entire cavity, with the
endochr ome loosely scattered within. In the next case, that
of Arthrodesmus incus (fig. 11), the resulting fusion of the
new growth, which ought to have formed two new segments,
is even greater than in the preceding instance, so that the

ARCHER AND DIXON, ON DESMIDIACES. 87

monstrosity almost represents an individual of three seg-
ments, so to speak. Here the interposed new growth has
formed, projecting to each side, but one angle, looking as
if but one new segment only had been formed, whereas,
it must be due really to both segments and spines of the
recently-grown portion being confluent. Of this malforma-
tion of A. incus I have on several occasions scen specimens.

In the next drawing, showing a remarkable monstrous
erowth of Huastrum didelta (fig. 12), we have a case some-
what similar to the preceding, but presenting additional odd
aberrations. The upper and lower portions of the figure
represent the side view of the older segments; between them
the new growth has been formed; but here not only does the
direction of the axis of growth assume a course at right angles
to the older segments, but, what is curious, the plane of the
new growth is at right angles to that of the older. In other
words, the new growth, which has formed almost what might
be called a new frond, not only has its ends projecting at right
angles to the ends of the original one, but it also presents a
front view, while the older segments show a side one. The
interposed new growth, projecting laterally, has formed the
usual linearly notched ends of the species, but one of them
has assumed a twist obliquely out of the straight direction.
The irregular space towards the centre of the specimen, as
represented in the figure, denotes a portion of the side of the
boundary wall, which, upon its inner surface, is there desti-
tute of chlorophyll granules, affording an opportunity to look
mto the central cavity, which thereabouts is more or less
empty, but the entire specimen beig otherwise, and to all
extremities filled with endochrome, in the ordinary manner,
as In a normal individual.

I exhibit a nearly similar case in Ewastrum insigne (fig. 13) ;
but the new growth has not assumed a different plane from
the old, and it is not so deformed in appearance. Of this
monstrosity I have met with two examples. The remaining
case 1s represented by the two drawings which show a state
of Tetmemorus Brebissonii (figs. 14 & 15), somewhat similar
to the preceding condition of Huastrum didelta and E.
insigne. In one the intervening growth has caused the old
segments to become somewhat twisted in regard to each
other, and, as in the preceding instances in Euastrum, it has
assumed a direction at right angles to the axis of the older
segments. The last sketch, (fig. 15,) which represents a
second instance met with by me of this phenomenon in the
same species, shows that the lateral extremity to the right is
really what ought to have been normally the new segment on

88 ARCHER AND DIXON, ON DESMIDIACEZ.

a line with the lower older segment, and that projecting to
the left the same for the upper, by reason of the fresh acces-
sion to the mass of endochrome, with its central series of
corpuscles, being continued in an uninterrupted, curved man-
ner from each of the older segments into the new. But the
new laterally projecting segments do not in either instance
form an equally armed cross, for what is wanting in their
length as well as breadth, as compared with the old, goes to
make up a somewhat quadrate central inflation. Tetmemorus
not being a compressed form like Euastrum, there is not the
same opportunity for the change of plane of growth shown
by the case in that genus (fig. 12), but that the new growth
has assumed a slight twist, is shown by the different relative
positions of the terminal emarginations.

The first figure of an abnormal Tetmemorus (fig. 14),
shows another state, though not bearing any connexion with
the curious aberration of the external form, and that is the
disposition of the cell-contents. The entire endochrome has
become transformed ito four green and four brown bodies,
the latter the smaller, and smooth in outline. This, how-
ever, does not appear to have any dependence on the external
abnormal condition, for I have frequently noticed the same
transformation of the cell- contents, especially in this species,
in the ordinary normally formed individual, as well as in

many other species—for instance, in Te¢memorus levis, Micras-
terias denticulata, Euastrum didelta, several Closteria, and
many others ; and often to the entire absorption of the cell-
contents to produce these spore-like bodies. In Tetmemorus
Brebissonii! have seen from one to a dozen or soof these bodies,
more often four only, sometimes green, sometimes red, and
sometimes alternately red and green. JI have not been able to
see any further development of those spore-like bodies. The
abnormal specimen from which the figure was taken I kept
on a slide moistened for many weeks, but no alteration took
place in this or any other respect, save that the red bodies,
from being undefined, grew more and more smooth in out-
line. These are, doubtless, similar productions to those
figured in the ‘ British Desmidiew,’ pl. iv, fig. f, as oecur-
ring in Desmidium Swartzii. There, however, there is but
one spore-like body formed in each joint. I have myself
met with this species in the state so admirably figured in
Ralfs ; and though I kept the specimens for some time living
no further alteration took place beyond the decay of the old
filament ; and the spore-like bodies themselves subsequently
perished. Bodies, which I suppose are of a similar nature,
as is well known, are occasionally met with im species of

ARCHER AND DIXON, ON DESMIDIACEZ. 89

Spirogyra, and which, as here, not being the result of con-
jugation, are formed by either a portion or the whole of the
green contents of a single joint being absorbed in their pro-
duction, and are spherical and spinous. My friend, Mr.
Edward Crowe, lately showed me specimens of Zygnema, in
which the entire cell-contents of many joimts of the fila-
ments had become consolidated into a globose or somewhat
pear-shaped and smooth spore-like body, which, by expansion
in one direction towards one side, eventually burst through
the boundary-wall, emerging into the surrounding water by
the rupture thus effected. Mr. Crowe informs me that he
was not able to trace their ultimate destiny, as they indeed
perished before undergoing any further development. It is
probable that these bodies, both in the Desmidians to which
I have above alluded, as well as the similar productions in
the above-mentioned Zygnemacze, in each case formed with-
out conjugation, are Gonidia, by which the organisms may
be severally propagated.—It may not be out of place to men-
tion here that I have several times noticed in Clostertum
lunula the entire cell-contents transformed into a dense longi-
tudinal series of flask-shaped bodies, with their narrow necks
projecting to the outer wall, precisely similar to those figured
by Carter (‘Annals of Natural History,’ 2d series, vol.
xvii, p. 114, pl. ix, fig. 9), as occurring in Spirogyra, also
by Henfrey (‘ Quart. Journ. Mic. Sci.,’ vol. vii, p. 27,
pl. ili, fig. 12), as occurring in his Chlorosphera Oliveri,
equivalent, I think, to Eremosphera viridis (de Bary) ; and
T imagine also the same as the unicellular alga mentioned by
Hofmeister in his paper ‘ On the Reproduction of the Des-
midiz and Diatomez,’ translated im ‘ Annals of Natural
History’ (vol. i, 3d series, p.1, January, 1858). In my
specimens of Closterium lunula alluded to, the longitudinal
mass of these flask-shaped bodies more than once has sug-
gested to me the hanks of onions as seen hanging up in the
market. I have never seen them, however, to produce what
Professor Henfrey considered the spermatozoids in his
Chlorosphzra, which plant, as I have before elsewhere stated
(‘ Natural History Review,’ vol. v, p. 258), though then
without knowing that De Bary and Henfrey had named it, is
of common occurrence in our district—Another curious
growth in the interior of Closteriuwm lunula I would just
notice. I refer to the production, within the otherwise empty
frond, of a slender jointed filament, contorted and twisted in
every direction, and occasionally inosculating; the joints
without any apparent contents, save a very few green granules,
scattered at considerable intervals. This I should imagine a

90 ARCHER AND DIXON, ON DESMIDIACEX.

parasitic growth, possibly at the expense of the original cell-
contents, though it is questionable how the germ could find
an entrance into the apparently uninjured cell. Such I also
thought the flask-shaped bodies above-mentioned, until I
met with Professor Henfrey’s remarks on the phenomenon
in Chlorosphzra, nor does it quite appear that his conjecture
is altogether proven.

Before attempting, in a measure, to account for the above
described curious external aberrations from the normal form,
it will, I think, be well briefly to draw attention to the mode
of division in this family of Desmidiaceze. So far as I can
make out, there can be little doubt that in these plants the
first step in the process of division is the formation of a sep-
tum at the central space or isthmus, whereupon the segments
become gradually removed more distant from each other by
the growth of a new cell-wall being interposed between them,
eventually forming two new segments. At first the new
growth is simple in outline, and pale in colour, but afterwards
assumes the characteristic, more or less complex form and
degree of tint of the species, and becomes filled with endo-
chrome, exactly similar to the older segments; in the free
species separation taking place, each older segment bearing
with it a new one, to replace that from which it has been
separated by the above-mentioned process of growth. Ac-
cording to Hofmeister (loc. cit.), “the new halves are at first
lined only by the protruded portions of the pellicle of the con-
tents belonging to the older half cells,” and “it is the margin
of the half shells which constitute the rings evident in many
species, e.g. Closterrum, Docidium,” &c. I believe that the
portion of each new segment first formed to be the end-lobe,
beneath which, at each side, are then gradually evolved the
lateral lobes. Nor can it be that certain specimens in
Micrasterias and Euastrum, occasionally met with, are more
than an apparent exception to this, in which the end-lobe is
not only seemingly absent, but in which, in its place, a more
or less deep sinus exists. For I should think the phenomenon
referred to is due to the arrest of growth of the end-lobe, and
which, not keeping pace with the expansion of the lateral
lobes, is left behind, thus producing the sinus.

I would here like to remark, parenthetically, that I do not
find that Hofmeister, in his paper alluded to, makes any refe-
rence to the circumstance of there being, occasionally at least,
cast off, immediately after division, from each of the new
segments a loose transparent coat, sometimes looking almost
like two empty segments, with their ends towards each other,
or back to back. What I refer to is well shown by Mrs,

ARCHER AND DIXON, ON DESMIDIACE. 91

Herbert Thomas (loc. cit., plate v, figs. 13 and 21) in the
object of her study, Cosmarium margaritiferum and C.
Thwaitesii. I have seen similar in other species, especially
smooth ones, such as Cosmarium Ralfsii, Cosmariumundulatum,
&ec. It does not appear to me evident what this pellicle-hke
production may be. It seems to me to be possibly only, as it
were, the matrix of gelatine formed during the act of division
and fresh growth, which may have become denser and firmer,
and from which the fronds then emerging and leaving it
behind, gives rise to a membranous appearance with the
doubly cup-shaped outline; or it may possibly be a secretion
deposited superficially during growth, even more comparable
than the usual gelatinous investment to what in the higher
plants is called “cuticle,” and which in them is occasionally
separable by peculiar treatment. In the growing Desmidians
referred to, however, this investing pellicle-like production
does not extend beyond the new segments, ceasmg at the
sutures. It is sometimes particularly remarkable m Docidium
(in D. clavatum I have noticed it), because it forms two
lengthened tubes (each, indeed, as long as one of the new
segments, and closely applied thereto), in apposition at the
closed ends and open at the opposite, from out of which the
fronds are to emerge, and indistinguishable till the process has
commenced. ‘This may be witnessed under the microscope
during its accomplishment, when it is seen that near the open
ends the cast-off tube is of a slightly undulated outline; being,
in fact, a cast from the new segments. In this species the
segments appear to me to possess one or two slight basal
inflations, though described as with only one in ‘ British
Desmidiee.’ I believe it, however, to be quite distinct from
D. Ehrenbergii. Whether a hyaline pellicle-like investment,
sometimes met with, entirely surrounding certain single indi-
viduals, and apparently like a loose tunic, is anything analo-
gous to the above-mentioned production, I cannot pretend to
say; but I have occasionally seen such in some species,—for
example, Euastrum didelta. 'This mvolving cyst does not
follow the boundary of the form, but is of a rounded or oval
outline, and generally, when I have noticed it, the contained
frond seemed to have lost vitality, the endochrome being
brownish. What I allude to is not to be mistaken for the
gelatinous investment surrounding the frond in so many Des-
midian species, being altogether different from anything of
the sort seen in fresh specimens. Possibly, like the former,
it may be due to its consolidation—here producing, by a pro-
cess of superficial condensation, as it were, a kind of skin,
from beneath which the intervening gelatinous substance has

92 ARCHER AND DIXON, ON DESMIDIACE®,

been absorbed. I hazard such a conjecture the more, because
something very like this seems actually to occur in some
species of Gleeocapsa, or alhed forms, in which the concentric
gelatinous layers seem to harden into so many frangible
investments.

In the foregomg very brief account of the mode of cell-
division which occurs in this family, it will be noticed that I
look upon the formation of a septum at the isthmus as the
preliminary or initial step in the process. Now it appears to
me that the accompanying figures represent individuals,
which, having taken on them the vegetative growth, or effort
to repeat themselves by transverse division, through some
inexplicable cause have omitted the formation of a septum. This
not having taken place simultaneously with the vegetative
activity being aroused, which, being in full energy, the frond
in each case proceeded to the development of new growth,
which, according to the law which prevails in this family, took
place, as usual, between the older segments. In consequence,
therefore, the resulting formation consisted of but one cavity,
and fresh endochrome being added,they each became entirely
filled. Nor do I think some instances lately under obser-
vation, and to which I will just allude, are a contradiction to
this. Specimens of Pentium cylindrus, to all appearance per-
fectly healthy, and manifestly undergoing growth, lately
occurred to me; of these, a few individuals presented them-
selves, in which various stages of the new growth, produced
in the usual manner in this species on a line with the older
segments, had been accomplished, m some cases the fronds
having attained to double the ordinary length—but im none
of the instances referred to was any appearance of a septum
evident. That the fronds had added to their length by recent
new growth was proved by its usual colourless cell-wall, as
compared with the red-tinted older segments. That there
was no septum was proved by the granular particles partaking
of a circulatory motion at and past the central point; and
indeed, when present, it is readily seen as a transverse line.
No further alteration took place in these specimens kept for
some time on a slide. Notwithstanding their not very
unusual appearance, for the absence of the central septum was
not very striking, and might not be noticed at first sight,
unless closely looked into, as well as there bemg no external
aberration in form, it appears to me that the specimens of
Penium cylindrus alluded to were so many illustrations of the
same abnormal mode of growth, extreme cases of which I
have tried to depict in the drawings. For I cannot easily
understand, without the original separation of the primordial

BRIGHTWELL, ON DIATOMACE. 93

utricle with the contents, and the formation round it at the
ends of new cell-wall, how an articulation could exist to allow
of the ultimate separation into two fronds of the old segments
with the portion that should appertaim to each of the newly
grown structure.

What causes the change in the direction of the axis of
growth in the specimens represented by some of the figures,
does not appear to me so readily to be accounted for. In
each case I should suppose the plant would cease to grow,
and the abnormal individual perish, unless, deed, each or
any might be supposed to possess the power of afterwards
forming a septum at the suture connecting the newly-grown
portion with the older segments, a second new growth
becoming then interposed, and the central misshapen structure
thus becoming eliminated.

On some of the Rarer or Unvescrisep Species of D1aro-
mMacem. Part II. By T. Bricutweut, F.L.S:

16. Actinocyclus areolatus.—Valve with a single spine or
projection on the upper margin of each area of the disc.
Varies in size from -023 to ‘043. (Plate V, fig. la, 16.)
The latter an assumed diagram of a front view.

Omphalopelta areolata, Ehr.—In shell cleanings and guano
not unfrequent.

Closely allied to A. wndulatus—Myr. T. West says the
spines or projections are often seen on alternate areas of the
dise only.

17. Actinocyclus trilingulatus.— Valves very convex, divided
into six segments, alternately elevated and depressed. The
elevated segments gradually rise from the circumference to
near the centre, where they are rounded off; each alternate
segment has a sub-marginal row of dots, or truncated pro-
cesses. Surface delicately punctato-striate, ‘035 to -073.

(Pl V, fig. 2; 2a, front view; 26, front view, in self-
division.) Of this large and beautiful species a few specimens
have been found in shell cleanings, West Indies.

“ 18. Actinocyclus spinosus, n. sp.—Convex, valves of. six
segments, alternately slightly elevated and depressed; a few

94 BRIGHTWELL, ON DIATOMACEX.

spines are occasionally detected in the margin ; each segment
with one or two elevated processes ; umbilicate, with the sur-
faces of the valve, except the umbilicus, punctate. Diameter
‘064 to ‘077. Shell cleanings.

19. Actinophenia splendens, Shadbolt.—Valve with two
plates, one with very fine oblique markings, the other with
much coarser markings, arranged in a somewhat pinnate
manner. (Pl. VI, fig. 15.)

A common species, varying greatly in size and number of
segments. Brick fields, Caermarthen, Mr. Okeden. Very
fine.

Syn.—Actinocyclus octodenarius,and numerous other species
of Ehrenberg :—Actinocyclus duodenarius, sedenarius, octode-
narius. Actinocy yclus sedenarius, Roper (‘ Mier. J ourn.,’ vol. 1,
pl. VI, fig. 2).—Mr. Roper’s fieure is unsatisfactory, giving
only the fine markings. (Smith, ‘Syn. Brit. Diat., ” vol. il,
Appendix, p. 86.) Professor Smith has published, with
doubts as to their distinctness, the three species named
above, which are certainly only varieties. It is unfortunate
that he should have transferred these names from the genus
Actinoptychus, in which they were placed by Ehr., to that of
Actinocyclus, creating thus the greatest confusion. Ehren-
berg’s Actinoptychus duodenarius, sedenarius, bioctodenarius,
we believe to be totally different from the form in question.

20. Actinoptychus interpunctatus, n. sp.— Valves with an in-
definite number of double rays, running from the centre to
near the circumference, the rays composed of short broken
lines, the imterstices between the pairs of rays filled up with
minute puncta, or dots. (Pl. VI, fig. 17.)

Hab. West Indies ; Monterey; New Zealand.

Not an uncommon marine species, from various localities,
and allied to Hupodiscus Ralfsii and Eup. sparsus.

The true species of this and the preceding genus we
believe to be few, while Ehrenberg, falling mto the extra-
ordinary error of viewing every variety in the number of
rays or septa as a species, has made a fresh nomenclature
and a new description of nearly all the species necessary.

21. Asterolampra Marylandica.—A variety with six seg-
ments, the normal number being eight. (Pl. V, fig. 3.)

22. Aulacodiscus sculptus (Eupodiscus sculptus), Smith.—
(Pl. V, fig. 5, a front view.)

Not often seen; and not before figured in this aspect, to
our knowledge.

BRIGHTWELL, ON DIATOMACE®. 95

23. Aulacodiscus radiatus, Bailey. — This is the true
Eupodiscus radiatus of the late Professor Bailey, as ascer-
tamed by authentic specimens. (See Mr. Roper’s remarks in
‘Micro. Journ.,’ vol. xix, pp. 19 and 262.) (Pl. V, fig. 10a,
side view ; 4, diagram of front view.)

24. Aulacodiscus levis.—A variety with eight, instead of four
processes. Alhed to Scader, but differs in the surface, being
perfectly smooth. (Pl. VI, fig. 13.)

25. Hyalodiscus cervinus, n. sp.—Valve, with exceedingly
minute puncta, or dots, scattered over the whole surface ;
centre, convex; valves, fawn coloured. Diameter, *054 to
7085. (Pl. V, fig. 9.) Arctic regions, Dr. Sutherland.
Shell cleanings, West Indies. Not uncommon.

The peculiar lines mentioned by Bailey in his description
of H. subtilis, as characteristic of that species, cannot be
detected in this, which, in other respects, agrees with it. Mr.
T. West says, with the greatest care and best sight, he cannot
detect these lines.

26. Craspedodiscus pyxidicula, Ehr.—Diameter of the
valve, ‘049; of the inner punctate portion, ‘021. (Pl. V,
fig. 4.) Guano, South America.

We take this to be the species referred to. The central
third part of the valve is slightly punctate, the puncta
diminishing till they almost disappear in the centre. The
residue of the valve with regular hexagonal reticulations.

27. Craspedodiscus marginatus, n. sp.—Valve, with a broad
impunctate margin, having about twenty rays, terminating
outwardly in small semicircles; residue of the valve
minutely punctate. Diameter, ‘037. (PI. V, fig. 7.) Bar-
badoes earth.

28. Craspedodiscus semiplanus, n. sp.—Margin very broad,
with faint radii and puncta. One-half of central part of the
valve smooth, the remainder with four or five radu. Dia-
meter, (024 to ‘035. (Pl. VI, fig. 12.) Barbadoes earth.

The margin is sometimes found impunctate.

29. Craspedodiscus coronatus, n. sp.—Centre of the valve a
small circle, enclosed by a rim of large square puncta, and
having within smaller puncta, diminishing in size towards the
central point. Outer portion of the valve minutely punctate.
Diameter, ‘022 to ‘068. (PI. V, fig. 6.) Barbadoes earth.

96 BRIGHTWELL, ON DIATOMACEX.

This very beautiful species has occurred occasionally, but
only in a broken state.

30. Cyclotella stylorum, n. sp.—Valve with the central circle
punctate, and with styliform rays diverging from it, each
ending near the margin in a large circular head. Diameter,
‘019 to 0°3, the former the common size. (Pl. VI, fig. 16a,
side view; 6, front view.) River Rohelle, Sierra ‘Leone.
Common.

31. Cyclotella radiata, n. sp.— Valve, end view, with simple,
strongly-marked radii, about 14 in -001. Front view, with
the ends of the radii appearing as puncta. Diameter, ‘018
to ‘023. (Pl. VI, fig. lla, end view; 4, front view.) Shell
cleanings, West Indies.

As many as ten frustules have been found in union, leaving
it doubtful whether this may not belong to the next genus.

32. Orthosira oceanica (Endictya oceanica), Ehr.—Dia-
meter, ‘027 to ‘035. (Pl. VI, fig. 16a, end view; 4, front
view.) Common in various gatherings, but not yet recog-
nised as British, unless the valve figured by Dr. Gregory
(Clyde Diat., pl. 1, fig. 47) be this form, which appears pro-
bable. A large and coarse species: it is seldom that more
than two or three valves are found united, and these are not
of the same frustules, so that the union by the connecting
membrane would seem to be the strongest.

33. Stephanogonia polygona, Ehr.—Valve, with central
portion impunctate and much elevated, united to the margin
by an indefinite number of rays, the spaces between which
are sometimes found to be very faintly punctate. Diameter,
015 to ‘025. (PL. V, fig. 8a, side view ; 4, front view.)

Richmond Earth, Virginia, N. A. Common.

From the peculiar form of this imteresting species, it
happens that it is seldom seen in any but an oblique position.

TRANSLATIONS.

Tur Mycerrozoa.—A contribution towards the knowledge of
the lowest Animals. By Dr. Anton De Bary.

Dr. De Bary’s object in the above paper, is to prove that
the tribe of organisms, heretofore brought together under the
general name of Myxogastric fungi, are not fungi; that they
are, in fact, not vegetables, but animals. The author does not
undertake, at present, to fix exactly their systematic position,
but he assigns them a place provisionally, between the Rhizo-
pods and the Gregarinze. Should his views be ultimately esta-
blished, the Zoologists will (as M. Tulasne has remarked),
thereby receive compensation in respect of the Corallines,
which the botanists have appropriated ; but we cannot help
thinking, that a great deal more evidence will be required,
and much more discussion will have to be gone through,
before botanists will be content to assent to the transfer of
the Myxogastric fungi to the animal kingdom.

Dr. De Bary’s paper is of great length, and we may add, of
great interest, but want of space forbids us from attempting
anything like a complete analysis of it. At the same time,
so far as regards the arguments in favour of the animal
nature of the creatures in question, it wil] be quite possible,
in a short space, to give a summary of the author’s contention.
To those readers of the ‘ Microscopical Journal’ who are
altogether unacquainted with the Myxogasteres, we should
strongly recommend a careful perusal of the entire paper,
premising that such perusal would be much facilitated by a
previous reference to Mr. Berkeley’s excellent remarks upon
the subject in his introduction to Cryptogamic Botany.

Dr. De Bary divides his paper into six chapters, or parts.
The first of these contains some general remarks upon the
structure of the tissue, and on the fructification in fungi;
and the second, an account of the peculiar characteristics of
a certain number of the more important genera into which
the Myxogasteres have been divided, such genera having been
founded principally upon the structure of the ripe spore-cases.
In speaking of the elaters or spiral threads in the genus

98 DE BARY, ON THE MYCETOZOA.

Trichia, the author observes, that the only correct account of
their structure is that given in this Journal in October, 1854,
and April, 1857.

In the third part, an account is given of the formation and
development of Aithalium septicum, and one of the principal
arguments in favour of the animal nature of the Myxogasteres
is grounded upon the supposed fact that the creeping threads
of mucilaginous matter, by the confluence of which the fruc-
tifyimg mass of Aithalium is formed, consist of sarcode. 'The
author says—“ The main substance of the threads is formed
“of that structureless, colourless, transparent, half-fluid
“ matter, called by Dujardin, sarcode, and by Ecken, shapeless
** contractile matter.

“The principal peculiarity of sarcode, viz., its high degree
“of independent contractility, is very remarkable in the sub-
“stance of these threads. It exhibits continual changes of
“form and fluctuating motions, such as are known to occur
“in the bodies of the Rhizopoda.

“Tts chemical nature also agrees essentially with the sar-
‘code of the lower animals. The rose-red colour produced
“by sugar and sulphuric acid, and by Millon’s test, and
“the brown colour produced by iodine, testify to its nitro-
“venous nature. It contracts and hardens in alcohol and in
“nitric acid, and becomes pale and transparent in acetic acid,
“without however becoming dissolved. On the other hand,
“it dissolves in liquor ammonie, in solution of caustic potass,
“even when very weak, and in solution of carbonate of
** potass.”

The spore-cases of all Mycetozoa are stated to be formed
of sarcode threads, essentially like those of dithaliwm. Dr.
de Bary has noticed in dithalium septicum, as well as in
Didymium serpula, and in a species of Physarum that when
the moisture is allowed to evaporate very slowly, and espe-
cially at a low temperature, the threads break up, by con-
traction, into irregularly shaped bodies, which, as_ the
desiccation continues, assume a waxy or horny consistence.
The whole substance of each of these bodies again suddenly
breaks up into numberless globular or oval cells, sur-
rounded by a double-outlined membrane, which exhibits,
under iodine and sulphuric acid, or under Schulze’s solution,
active and intense cellulose reaction. All these cells in a
mass are imbedded in a homogeneous hyaline substance not
exhibiting cellulose reaction. This substance is more
strongly developed at the outer surface of the mass of cells.
It softens in water, so that the cells can be separated by
pressure, and then surrounded by a thin layer of the inter-

DE BARY, ON THE MYCETOZOA, 99

cellular substance. These waxy bodies change back again into
the ordinary sarcode threads under heat and moisture, and
Dr. De Bary considers that, by passing into this waxy cel-
lular state, the sarcode threads are enabled to retain their
vitality during dry hot weather, and through the winter.

In speaking of the ordinary spore-formation, the author
states that the formation of spores in the Mycetozoa always
takes place by division of the plasma around previously-
formed nuclei, and never directly from the threads of the
capillitium. He alleges that Berkeley’s observations on
Enerthenema are incorrect, and doubts also the accuracy of
the latter’s account of the structure in Badhamia ; admitting,
however, that he (Dr. De Bary) is not acquainted with the
latter genus.

The history which is given of the germination of the
spores of the Myxomycetes is of considerable interest, and
has been confirmed to some extent by the observations
of Hoffmann in the ‘ Botanische Zeitung,’ for June 17,
1859. When placed in water, and protected from evapora-
tion, the membrane of the spore opens, and its contents
escape in the form of a cell, clothed only by a very thin pri-
mordial utricle, thus resembling the reproductive cells of
many alge. ‘These escaped cells undergo changes of form,
eventually exhibiting one or two cilia, and two or three
vacuoles, of which one at least always pulsates. They have
also a motion of progression and rotation, as in the case of
ordinary zoospores.

After a few days, bodies appear, differing from the zoospores
in their larger size, the greater number and irregular dispo-
sition of the vacuoles, the want of cilia, and of oscillating and
rotating movements, and by the protrusion of parts of the
body, precisely as in the Amzebe ; like which they have also
a creeping motion, and are perpetually changing their form.
The author states that these singular bodies are not inde-
pendent productions, but that they are produced from the
zoospores, and that by the further development of them,
the spore-cases are eventually formed. He says—

“Tf, therefore, on the one hand, the development of Amebe
from the products of the germination of the spores, and, on
the other, the production of the sporangia from the sarcode-
threads, which, as regards structure and movements, might
be described as colossal filamentary dmeée, be established,
it is an obvious conclusion that the latter arise from the
farther development of these dmebe. And this has been
confirmed by direct observation in A’thakum septicum,
Lycogala, and Stemonitis obtusata ....... Direct develop-

100 DE BARY, ON THE MYCETOZOA.

ment of the fructifying threads from the Amzbe, produced
by the growth of the zoospores, appears to me beyond a
doubt. And, in accordance with this assumption, is the fact
of the frequent occurrence of common Ameebee (radiosa, verru-
cosa, Ehr.) in tan, rotten wood, &e., the habitats of the Myce-
tozoa. It remains doubtful, however, whether the sarcode-
threads, which directly form the spore-cases, are the product
of a single Ameeba, or arise from the confluence of several.”

Dr. De Bary lays some stress upon the fact that the Myce-
tozoa, when in the amzboid condition, exhibit in the sub-
stance of their bodies (like the aquatic Amebe) solid matter
taken in from without, such as cells of algze, spores of fungi,
&e. He says that if these “ ingesta” can be considered to
be food, the fact would establish the animal nature of the
Mycetozoa, because, if an organism eats, it must be an
animal. He admits, however, that there is no proof that
the ingesta are food, and that there is nothing to show that
they may not find their way accidentally into the bodies of
Amebe, as Dujardin has suggested. Considering, however,
that the movements of the Amebe resemble those of Acti-
nophrys, and that the movements of Actinophrys are cer-
tainly made in quest of food, the author considers it pro-
bable that the aquatic dmebe and the amzboid Mycetozoa
do really eat.

After noticing the affinity of the Mycetozoa with the Si-
phone and Saprolegniez, especially with Pythiwn amongst
the latter, Dr. De Bary says—

“ But, notwithstanding all these analogies, and eyen as-
suming that the vegetable protoplasm in its composition
and movements is closely allied to sarcode; assuming also,
that many plants, whilst in the condition of zoospores,
have the capacity of spontaneous locomotion, and are also
contractile ; assuming also, that the difference in the moye-
ments of the Mycetozoa and of divers plants is only quanti-
tative ; nevertheless, free motion exists in the Mycetozoa
with an intensity and duration unequalled in any plant ....
.... We should be content to leave the Mycetozoa in the
vegetable kingdom if nothing analogous to them could be
found amongst animals. But, inasmuch as their structure,
their mode of life, their motion from the time of the appear-
ance of the zoospores accord most fully with those of certain
animals; inasmuch also as the perfect sarcode-threads hardly
differ, except in size, from the sareode-threads of the Rhizo-
poda, the result is that the ‘Mywxomycetes’ must take
their place as ‘ Mycetozoa’ in the animal kingdom.”

In the above remarks, we have given what we believe to be

DE BARY, ON THE MYCETOZOA. 101

a full and fair account of Dr. De Bary’s argument in support
of his proposition. We have not time or space to dwell at
any length upon the weak parts of his case. One or two
points, however, may be mentioned. The fact of the formative
threads containing sarcode would not go far to prove their
animal nature. Sarcode and vegetable protoplasm are admitted
to be nearly allied ; and the author himself brings forward the
fact of our imperfect knowledge of the chemical natnre of
sarcode, by way of explanation of an unexpected chemical
reaction which he found in the sarcode-threads. (See p. 125.)
We would further observe that his views of spore-formation
in the Myxomycetes generally, are in direct opposition to those
of Berkeley, Corda, and Tulasne.

The careful conclusions of so eminent an observer as Mr.
Berkeley cannot be set aside by a mere allegation of their
inaccuracy, as has been done by Dr. De Bary in the instance
of Enerthenema. In Badhamia, again, in which Dr. De Bary
throws doubts upon Mr. Berkeley’s opinions, we can state
from our own observation, that the spores are certainly not
formed in the manner described by the author as occurring
in the other Myxogastric genera; and Mr. Berkeley’s obser-
vations, if correct (which we see no reason to doubt), would
almost suffice to upset Dr. De Bary’s theory ; for ifit be once
admitted that Badhamia is truly fungoid, no doubt could
exist as to the nature of the rest of the Myxomycetes. With
regard to the development of the amzboid bodies out of the
zoospores, we may call attention to a paper written a few
years since by Dr. Hartig (an abstract of which was given in
a former volume of this journal), containing the result of some
observations on the Phytozoa of the Antheridia of Marchantia,
tending to show that those Phytozoa become ultimately
transformed into Amb. The inference from the latter
observations would be that Dr. Hartig’s amzbe were vege--
tables ; for if they were really formed from the substance of
the Phytozoa, they must necessarily partake of the nature of
the latter. On the other hand, Dr. De Bary, assuming the
animal nature of Amebz generally, and finding Ameeb:ze pro-
duced from the spores of the Myxogasteres, draws the con-
clusion that the Myxogasteres are animals. Whatever may
be the result of the discussion which Dr. De Bary has origi-
nated, good service will be done to science if it should lead,
as we hope it may do, to a careful and accurate investigation,
both by botanists and zoologists, of what we think we may
still call the Myxogastric fungi.

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103

NOTES AND CORRESPONDENCE.

On the Universal Screw.—The remarks of Mr. Brooke, ap-
pended to my paper on the universal screw, which was pub-
lished in a previous number of the ‘ Journal,’ are so entirely at
variance with my owu experience, that I venture to give
somewhat of an answer to each of his paragraphs, excepting
the first, which is merely introductory.

In the first place, then, no workman, be he ever so
“ practised,’ can cut up a screw-tool by hand, that, as an
exact counterpart of the “hob,” shall be equal to one made
by a screw-cutting lathe; and there are plenty of shops in
London and other places where screw-tools can be properly
cut up, by comparatively inexperienced workmen.

“The practical difficulties” next mentioned by Mr. Brooke
are entirely illusive. Ifthe method of gaugimg the tops of
the threads were sufficient, nothing would be easier than to
make both inside and outside screws fit easily and pleasantly
in the gauges, and they would screw together in a similar
manner; the variations which really occur in the screws
made by different makers, to cylindrical gauges of the same
size, are at the bottom and sides of the threads.

Mr. Brooke, in the next paragraph, states, that ‘ the
bottom of the outside screw can be most easily gauged ;”
but I am convinced that he cannot have tried it; for he goes
on to say, that if screws “ enter easily and pleasantly,” they
must “necessarily” differ in size some “ two or three thou-
sandths of an inch,” whereas Mr. Whitworth has shown that
a variation of one ten-thousandth of an inch is most dis-
tinctly perceptible.

The reason why the adjustible screw-cutting gauge pos-
sesses an “immunity from the same wear as that to which
the screw-tool is liable,” is because it has so very little to do.
The screw-tool cuts up the whole depth of the thread, the
cutting-gauge only removes that which is left by the wear of
the screw-tool.

I thmk many persons will find it difficult to understand
My. Brookes’s next paragraph, and the only explanation I

104. MEMORANDA,

can give is this: The “ gauge-taps” issued by the Micro-
scopical Society are slightly taper and differing in size, con-
sequently, when they are sent out to the makers, there are
directions with them, as to how far each one is to screw up
the nose-piece of the microscope, and that if the screw is made
only °125 in length, it may prevent some of the taps from
screwing up as far as they should. On my own part, I see
no objection (if proper means be employed) to the maker
cutting the screw in whichever way he pleases. I perfectly
well remember pointing out to Mr. Brooke the assistance it
would be to the workman when cutting the mside screw
by hand, to make it a greater length than *125, but, if the
work be done in a machine, this difficulty ceases; and it is
important to save the wear of the screw-tool as much as
possible.

And now, in conclusion, may I also tell what I know as to
how “the plan recommended by the Microscopical Society
has been found to work well amongst those who have adopted
it.’ Of the three houses besides our own who are using the
“universal screw,’ one has ordered a set of the cutting-
gauges. Another firm are making their outside screw con-
siderably smaller than Whitworth’s gauge, and their inside
screw to the Society’s tap. The other firm are also using
the Society’s tap, but they are making their outside screws
considerably larger at the bottom than Whitworth’s gauge,
and it is this firm, so far as I can ascertain, who have altered
the nose-pieces of our microscopes, but, in one instance which
has come to my knowledge, after having made the alteration,
an object-glass which they sent subsequently, proved too
large, and would not screw into the microscope at all.—
Ricuarp Buck, Upper Holloway.

Harrison on a new Pleurosigma. — Somewhat better than
twelve months ago I was visiting a friend in Lincolnshire
(W. Parker, Esq., of Thornton House), and he showed me a
slide containing a few frustules of a Pleurosigma which I
had not before seen; I enquired where he had obtained them,
and he went with me to the drain (a run of fresh water), but
we could not find any at that time, I was paying another
visit, to the same friend, about three weeks ago, and we pro-
cured a pretty good gathering of them, and as I could not
find any account of it in any previous work, I have named
it Pleurosigma Parkerii. It is about the same size as the P.
fasciola, but broader in proportion to the length, and the
ends not so much contracted,

MEMORANDA. 105

Length -0040” to -0045” of an inch; striz 50 to 55 in
001."
I enclose a drawing magnified 400 diameters.

{iT 2
oes

= ee
pa

Pleurosigma Parkeru.

Valve broadly lanceolate, acute extremities produced,
flexure considerable ; colour pale yellow. Length of valve
0038" to ‘0040"; transverse striz ‘0060’, and stronger than
the longitudinal. Fresh water. Thornton-le-Moor, Lincoln-
shire, Mr. W. Parker.

106

PROCEEDINGS OF SOCIETIES.

Microscoricat Society, Nov. 9th, 1859.
Dr. Lanxesrer, President, in the chair.

John Stainton, Esq., Longbridge, near Warwick; M.
Foster, jun., Esq., Huntingdon; J. Burge, Esq., Fulham ;
J. L. Bennett, Esq., Pentonville-road; Thos. Hunt, Esq.,
23, Alfred-place, Bedford-square; and Jas. Smith, Esq.,
Soley Terrace, Pentonville, were balloted for and duly elected
members of the Society.

Two papers were read—one by Dr. Greville, ‘On Campylo-
discus’ (‘' Trans.’ p. 29) ; the other, ‘On Diatomacez from the
Ohio,’ by Professor Hamilton Smith (‘ Trans.’ p. 33).

Mr. Loss said—It is with much pleasure I bring before
the notice of the meeting the latest production of Messrs
Powell and Lealand ; and we are all of us aware how back-
ward our friends are to make public their own doings. It is
a new achromatic condenser of 170° aperture, having, as in
the old one, three combinations, so arranged as to be
used separately when required. The diaphragm has eleven
apertures, and there are three stops and two semicircles.
The stops and semicircles can be placed in any portion of the
field, so as to produce the best definition. The movements
of the diaphragm and stops are so contrived as to be adjusted
with the greatest ease and freedom, and not, as in all former
condensers, placed so as to give the manipulator the greatest
trouble to effect the desired end. One thing is required
when using this condenser with the full aperture—yiz., to
have the objects mounted on, as well as covered over with,
thin glass; and I think if our object-mounters were to
mount all objects in this way on mahogany slides ; it would
be far better, and they would be less lable to break
than those mounted on glass slides. The delicate markings
of the Diatomacez are beautifully defined; with this new
condenser, using the 3, 7, and #s object-glasses; the mark-
ings on the Amician test are made as fully apparent as are
those of the Hippocampus; and the delicate lines of P.

PROCEEDINGS OF SOCIETIES. 107

Acus are easily defined. The price of the condenser is eight
guineas, being only one guinea more than the old one of 100°
aperture.

I have also to bring before the notice of the meeting, a
method which I have some time adopted for showing the
phenomena of the rings round the optic axes of crystals,
and which is chiefly my own invention. Mr. Woodward, the
author of a treatise on polarised light—Professor Potter, of
the London University—and Mr. Darkin, of Lambeth, have
all seen it; and all agree.that they have never seen the phe-
nomena so beautifully displayed. It consists—

1. Of an eye-piece with lenses about the depth of those
usually put in the third eye-piece. There is no diaphragm
between the lenses, which are so adjusted that the field-lens
may be brought nearer to, or farther from, the eye-lens, as
occasion may require, thus giving different powers and
different fields; and when adjusted for the largest field it
will be full fifteen imches, and take in the widest separation
of the axes of the arragonite ;

2. A crystal stage to receive the crystals, and of the usual
construction, into which is screwed a blue tourmaline ;

3. A large Nichol’s prism as a polariser ;

4. A common single double convex three or four-inch
lens, set in the middle of a brass tube, long enough, when
screwed into the body of the microscope, to reach the pola-
riser, so that all extraneous light may be excluded. At the
bottom of this tube there is a blue glass, for the purpose of
giving white light when a lamp is used. The concave mirror
should be used with a bull’s-eye condenser by lamplight;
the condenser may be dispensed with by daylight. Messrs.
Powell and Lealand are well acquainted with the above
apparatus.

The crystals best adapted to show the phenomena of rings
round the optic axes are—

Quartz, a uni-axial crystal, one system of rings, no entire
eross of black, only the ends of it, the centre being coloured;
and as the tourmaline is revolved, the colour gradually
changing into all the varied tints of the spectrum, one
colour only displayed at once in the centre ;

Quartz, cut so as to show right-handed polarisation ;

Quartz, cut so as to show left-handed polarisation—that
is, the one shows the same phenomena when the tourma-
line is turned to the right, as the other does when turned to
the left ;

Quartz, cut so as to show straight lines ;

Cale Spar, a wni-axial crystal, one system of rings, and a

108 PROCEEDINGS OF SOCIETIES.

black cross, which changes into a white cross, on revolving
the tourmaline, and the colours of the rings mto their com-
plementary colours.

Topaz, a bi-axial crystal, although it has two axes, only
exhibits one system of rings with one fringe, owing to the
wide separation of the axes; the fringe and colours change
on revolving the tourmaline; this is the case in all the
erystals ;

Borax, a bi-axial crystal, the colours more intense than im
topaz, but the ri ngs not so complete, only one set of rings
taken in, from the same cause as topaz;

Rochelle Salt, a bi-axial crystal, the colours more widely
spread, very beautiful, only one set of rings taken in;

Carbonate of Lead, a bi-axial crystal, axes not much sepa-
rated, both systems of rings exhibited, far more widely spread
than those of nitre ;

Nitre, a bi-axial crystal, axes very closely approximated,
colours intense and “beautiful, the rings are also closely
united ;

Arragonite, a bi-axial crystal, axes rather widely separated,
but both systems of rmgs exhibited, and decidedly the best
erystal for displaying the phenomena of bi-axial crystals.

‘The field-lens of the eye-piece requires to be brought as
close as possible to the eye-lens, to see properly the pheno-
mena in quartz and arragonite; it must be placed at an-inter-
mediate distance for viewing topaz, borax, Rochelle salt, and
carbonate of lead ; it must be drawn out to its fullest extent
to view nitre and cale spar.

The powers of the micro-polariscope cannot be better
displayed than in the exhibition of the foregoing pheno-
mena; there is nothing more beautiful, and few studies
more interesting and enlarging to the mind, than that of
light, whether common or polarised, which must be entered
upon, if the phenomena are to be understood.

The crystal eye-piece, with an artificial tourmaline as an
analyser, will be found very useful for polariscope objects
generally. There is some spherical aberration, but the
largeness of the field far more than compensates for the same.
It does best for those objects that require the two-inch
object-glass.

I have brought with me this evening two objects—a flea
and an insect named Chalifer. They were mounted by one
of the members of this society, Mr. Farmer, of Hornsey ; and
are remarkable for the clear manner in which the muscles
are brought out, as also the striated fibre of the same; and
which, at the instigation of our much-esteemed president,

PROCEEDINGS

OF SOCIETIES. 109

Dr. Lankester, I present to the Society, to be placed in their
cabinet of curiosities.

December \4th, 1856.
Gro. Busx, Esq., in the chair.

Sir William Dennison, Governor of Sydney, Australia ;
C. J. H. Allen, Esq., 28, Woburn-place; Matthew Marshall,
_jun., Esq., 12, Lyndhurst-grov e, Peckham ; Benjamin

Standring, Esq., 152, Minories; Thomas Ross, Esq., Feather-
stone-bridge ; and George Andrews, jun., Esq.. 55, Friday-
street, were balloted for, and duly elected members of the
Society.

Dr. Wallich read a paper ‘On Siliceous Organisms’
(‘ Trans.’ p. 36).

Mr. Roper read a paper ‘ On Triceratium’ (‘ Trans.’ p. 55).
November 9th, 1859.

The following publications, &c., have been presented to
the Microscopical Society since the publication of the last

Journal :
PRESENTATIONS.
Books.

Professor Huxley’s Oceanic Hydrozoa_

Recreative Science, a Monthly Journal of Intellectual
Observations, 5 Nos.

Smithsonian Contributions to Knowledge, Vol. X.

Smithsonian Report for 1857.

Boston Journal of Natural History

Proceedings of the American Philosophical Society,
Vol. VI.

Canadian Journal of Industry, Science, and Art

Academie Royale de Belgique Bulletins, 1858

Ditto, Annuaire, 1858

Bericht tber die V erhandlungen der Botanischen,
1858. F. Cohn 3

The Fauna of Blackheath and its vicinity .

Reply to the “Statement of the Trustees of the
Dudley Observatory.”” By B. Apthorp Gould, jun.

Defence of Dr. Gould by the Scientific Council of the
Dudley Observatory

Quarterly Journal of the Geological Society, No. 59 .

On the Nomenclature of the Foraminifera. By
W. K. Parker and T. R. Jones, Part 1 .

Journal of the Proceedings of the Linnean Society,
Nos. 13 and14_ 4

British Journal of Dental Science, Nos. 37 ‘to 40

The Photographic Journal, several Nos. .

On the Meterology of England, 1857 to 1859

‘The Institutes of the British Meteorological Society .

Reports of the Council of ditto . :

Presented by

Ray Society.

The Editor.
The Society.
Ditto.

Ditto.
Ditto.
Ditto.
Ditto.

The Author.
The Society.

The Author.

Ditto.
The Society.

The Author.

The Society.
The Editors.
Ditto.

Jas. Glaisher.
Ditto.
Ditto.

110

On the Determination of the Mean Temperature of
every Day in the i from 1814 to 1856. By J.
Glaisher

The Meteorological and Physical Effects of the Solar
Lclipse of March 15th, 1858. By J. Glaisher

On the Meteorology of Scotland for 1857. By J.
Glaisher..

Several Meteorological Tables. By J. Glaisher

Quarterly Return of Marriages, Births and Deaths
for 1856 and 1857 .

Notices pour servir a Petude des Polypiers nageurs ou
Pennatulides. J. A. Herklots ,

Musée Royal d’Histoire Naturelle a Ley de

Two Slides of Insects to show the Miiscilae Strie.

December \Ath.

On the Nomenclature of the Foraminifera.
K. Parker and T. R. Jones. Part 2 :

Canadian Journal of Industry, Science, and Art.
No. 24 .

The Journal of the Royal Dublin ‘Society. No.15

The Quarterly Journal of the Geological one:
No. 60 . ;

Journa] of the Proceedings of the Linnean Society

Photographic Journal. 3 Nos. .

Note sur une espéce de Dothidea M_ le Pasteur Duby

By W.

Microscopic Portralts.

Professor Quekett. Charles Woodward.
— Brand. KE, E. Meeres

PURCHASES.

Nouvelles suites 4 Buffon, formant, avec les muvres de cet auteur, un

PROCEEDINGS OF SOCIETIES.

Presented by

Jas. Glaisher.
Ditto.

Ditto.
Ditto.

Ditto.

The Author.
Ditto.
KE. G. Lobb.

The Authors.

The Editor.
The Secretary.

The Society.
Ditto.

The Editor.

The Author.

Presented by Geo. Jackson, Esq.
Andrew Ross.

cours complet d’historei naturelle collection accompagnée de Planches.

Evenings with the Microscope. By P. Gosse.

The following copies of British Museum publications were

also presented to the Society :

Catalogue of Lepidopterous Insects. Part 1.
List of Lepidoptera set Lito.8
18 Parts.

», Hymenoptera
Catalogue a
List of Diptera
», Homoptera
» Hemiptera
», Coleoptera
Guide to the Mollusca
Catalogue of Entozoa
List of British Animals
Catalogue of British Hymenoptera
4 Fossorial Hymenoptera
>. Marine Polyzoa

_—
SR RNR Re Oe Or 59 0

”

Papilionide.

W. G. Searson, Curator.

PROCEEDINGS OF SOCIETIES. Tit

HISTORIC SOCIETY OF LANCASHIRE AND CHESHIRE.

On the Diatomacee of the Neighbourhood of Liverpool.
By Tuomas Comser, Esa.
(Read 16th December, 1858.)

In laying before the Society the following contribution to
' the Liverpool Flora, I have been influenced by a wish to
increase, in some degree, the knowledge of the Natural
History of the neighbourhood, towards which so much has
been done by other Liverpool naturalists; and although I
have confined myself to a single order I trust the subjoined
list will be of some use in this respect. Iam also not without
hope that it will assist those whose researches have been
extended over a wider field than my own, in their investiga-
tion into the geography of the order, at present in a very
unsatisfactory state.

i have adopted the limits established by Dr. Dickenson in
his Flora of Liverpool, extending to the north as far as
Southport. In this district there are found as many as.257
described species of Diatomacez, affording representatives of
51 genera. Of these 120 are fresh water, 64 brackish, and
73 marine species: these last numbers are, however, only
approximate, in consequence of many species being some-
times found in both fresh and brackish, and others in marine
and brackish, localities. For instance, I have gathered
Navicula Westit and Stauroners salina, both generally con-
sidered altogether marine species, in a living state in a pool
to which no sea water could possibly have got for at least
eight months.

Those species usually found in Alpine situations, such as
Navicula crassinervia, N. serians, some of the Pinnularie and
Odontidia, Tabellaria flocculosa, and several of the Melosire
and Orthosire. are absent; but this is only what would be
expected: another deficiency for which I cannot account
occurs in the allied genera of Podosphenia, Rhipidophora and
Lichnophora, containing in all ten species, of which the only
representative found in this neighbourhood is 2. Dalmatica

I have used Professor Smith’s nomenclature, as being the
best known, even in many instances where it is opposed to
my own views. Only twenty of the species, discovered since
the publication of the second volume of that work, are not
described in his synopsis.

My best thanks are tendered to three members of the
Microscopic Club of this town, Messrs. G. M. Browne,

112 PROCEEDINGS OF SOCIETIES.

T. Sansom and L. Hardman, who have very greatly assisted
me ;. how much, their initials, attached to the Jocalities given
on their authority, will show. For the other localities and
for the naming of all, I am myself answerable.

Epitnemtia, Kitzing.

L. turgida, Sm.—Frequent. Well at Sefton, August, 1856,
and July, 1857; Bidston marsh, October, 1856, and
many other localities

F.. Zebra, Kiitz.— Bidston marsh, October, 1856.

E. Argus, Sm.—Railway bridge at Spital, September, 1858,
L. H.—Well in Brombro’ wood, September, 1858.

FE. alpestris, Sm.—Well at Sefton, August, 1856, and July,
1857; railway bridge at Spital, April, 1857.

E. Sorex, Kiitz.—Sefton well, August, 1856, and July, 1857;
Bidston marsh, August, 1858, &c.

EL. Westermanii, Sm.—Bidston marsh, October, 1856, and
October, 1857—Birkdale marsh, G. M. B.

EL. rupestris, Sm.—Bridge at Spital, Sept., 1858, L. H., &e.

E. gihba, Wiitz.—Frequent. Bidston marsh, Oct., 1856, &c.

L. ventricosa, Kiitz.—Railway bridge, Highfield, L. H.

Kunomia, Ehrenberg.
E. Arcus, Sm.—Pit at Rock ferry, June, 1856.
CymMBELLA, Agardh

C. Ehrenbergii, Kiitz.— River Alt, near Sefton, July, 1837.

C. cuspidata, Kiitz.—Always occurs sparingly. Thornback
pool, Crosby, September, 1856—Southport, June, 1857,
G. M. B.

C. maculata, Kiitz.—Patrick’s well, Spital, March, 1857.

C. Helvetica, Kiitz.— Well at Sefton, July, 1857.

— Var B.—Thornback pool, Crosby, Sept. 1856.

Ampuora, Ehrenberg.

A. ovalis, Kiitz.—Frequent. Canal bridge over R. Alt, &c.

A. affinis, Kiitz—Not uncommon. Bidston marsh, July,
1856, and October, 1857, &c.

A. salina, Sm.—Bidston marsh, July, 1856; Great Float,
April, 1858.

Cocconets, Ehrenberg.

C. Pediculus, Khr.—Lock at Sefton, July, 1857; stream near
Shotwick, Cheshire, June, 1858.

C. Placentula, Ehr—Very common; in fact in almost all
fresh water gatherings.

C. Thwaitesii, Sm.—Rock in Dingle, March, 1857.

C. Seutellum, Ehr.—New Brighton, March, 1857, L. H.

C. eccentrica, Donk.—New Brighton sands, September, 1858.

PROCEEDINGS OF SOCIETIES. 113

Coscinopiscus, Ehrenberg.

C. radiatus, Ehr.—Common. New Brighton in several
gatherings, &c.

C. eccentricus, Khr—Common. New Brighton, &e.

C. concinnus, Sm.—R. Fender, Bidston marsh, June, 1856;
New Brighton, April, 1858—Southport sands, August,
1858, G. M. B.

Kupopiscus, Ehrenberg.

Li. fulvus, Sm.—Bidston marsh, October, 1857.

£. crassus, 8Sm.—New Brighton—Southport sands, August,
1858, G. M. B.

Lf. radatus, Sm.—Southport marsh, June, 1857; New
Brighton, April, 1858.

£. Ralfsii, 8Sm.—Southport marsh, June, 1857; New Brigh-
ton, April, 1858.

Actinocycuus, Ehrenberg.

A. undulatus, Kiitz—Common. New Brighton, &c.

Ae dughenariity ) wes Brighton; April 1858: Bidston marsh
A. sedenarius, Ovtober: 1857 2
A, octodenarius, : : ;

TRICERATIUM, Ehrenberg.
T. Favus, Ehr.—New Brighton, April, 1858—Southport
sands, August, 1858, G. M. B.
T. undulatum, Khr.—New Brighton, April, 1858—Southport
sands, August, 1858, G. M. B.
CycLore.ua, Kiitzing.
C. Kutzingiana, Thw.—Aintree pit, June, 1857; Bidston
marsh, August, 1858.
——_—__— Var 3.—Thornback pool, Crosby, Sept. 1856.
C. operculata, Kiitz—R. Dee, near Queen’s ferry, June, 1858.

Campytopiscus, Ehrenberg.

C costatus, Sm.—R. Alt, Sefton, July, 1857; well in Brom-
bro’ wood, May, 1857.

C. spiralis, Sm.—Bidston marsh, October, 1856.

C. cribrosus, Sm.—Bidston marsh, October, 1857.

C. parvulus, Sm.—Head of Wallasey pool, May, 1857; great
float, April, 1858.

SURIRELLA, Turp.

8. biseriata, Bréb.—Hoylake, October, 1856, G. M. B.

S. linearis, Sm.—Patrick’s well, Spital, March, 1857; pit at
Aintree, June, 1857.

S. constricta, Sm.—Bidston marsh, October, 1857.

S. data, Sm.—New Brighton, September, 1858.

114. PROCEEDINGS OF SOCIETIES.

S. splendida, Kiitz.—Bidston marsh, October, 1856.

8. striatula, Turp.—Frequent in brackish water. Bidston
marsh, &c.

S. Gemma, Ehr.—Primrose hill, New ferry, July, 1856;
Bidston marsh, October, 1857.

S. fastuosa, Ehr.—New Brighton, April, 1858.

S. Craticula, Ehr.—Bidston marsh, October, 1856.

S. ovalis, Bréb.—Frequent, Railway bridge, Spital, May,
1857, &c.

8. panduriformis, Sm.—Rock at Storeton, March, 1857.

S. ovata, Kiitz—Common in fresh water.

S. salina, Sm.—Sands at Great Meols, May, 1857.

S pinnato, Sm.—Pit at Rock ferry, March, 1857—Railway
bridge, Highfield, L. H.

S. angusta, Kiitz—Rock at Storeton, March, 1857.

S. minuta, Bréb.—Lock at Sefton, July, 1857.

S. Crumena, Bréb.—River Fender, June, 1856; near Wallasey
pool, Seacombe, April, 1857; River Alt, July, 1857, &c.

TRYBLIONELLA, Smith.

T. gracilis, Sm.—Not uncommon in brackish water Fre-
quently from Bidston marsh.

——— Var (3.—Primrose hill, New ferry, July, 1856.

T. marginata, Sm.—Not uncommon in brackish water. Bid-
ston marsh, October, 1857; Seacombe, April, 1858, &c.

T. punctata, Sm,—Primrose hill, New ferry, July, 1856.

T. acuminata, Sm.—Frequent in brackish water. Bidston
marsh, &c.

CyMATOPLEURA, Smith.

C. Solea, Sm.—Bidston marsh, Oct. 1856, and Oct. 1857.

C. apiculata, Sm.—F requently met with, R. Alt, &c.

C elliptica, Sm.—Bidston marsh, October, 1857; R. Alt,
July, 1857, &c.

Nirzscuia, Hassall.

N. sigmoidea, Sm.—Not uncommon. R. Alt at Sefton, July,
1857, &e.

N. Brébissonii,Sra.—Bidston marsh, July, 1856, and Mar. 1856.

NV. Sigma, Sm.—Not uncommon in brackish water. Bidston
marsh, frequently.

N. linearis, Sm.—Rather common. R. Alt, &c.

N. angularis, Sm.—New Brighton, March, 1857, L. H.

N. Amphioxys, Sm.—F requent, though generally but few in a
gathering. Moss from Rock ferry, October, 1857.

N. minutissima, Sm.—Patrick’s well, Spital, March, 1857.

N. vivax, Sm.—Bidston marsh, October, 1857—Birkdale
marsh, June, 1857, G. M. B.

PROCEEDINGS OF SOCIETIES. 115

_N. virgata, Roper.—Sands at Great Meols, May, 1857; New
Brighton, September, 1858.

Sp. (Zpithemia marina, Donk.) Sands at New
Brighton, September, 1858.

N. dubia, Sm.—Eastham marsh, September, 1858; Skew
bridge, Bebington, May, 1856.

N. bilobata, Sm.—Bidston marsh, October, 1857.

N. plana, Sm.—Not uncommon. Bidston marsh, &c.

N. birostrata, Sm.—Kastham marsh, September, 1858.

N. Closterium, Sm.—Not uncommon. Southport sands, Au-
gust, 1858; Eastham marsh, September, 1858; Bidston
marsh on several occasions.

N. Tenia, Sm.—Southport sands, August, 1858.

Ampuiprora, Ehrenberg.

A. alata, Kiitz.—Not uncommon in brackish marshes. East-
ham marsh, September, 1858, &c.

A. Ralfsii, Arnott.—New Brighton sands, September, 1858.

A. paludosa, Sm.—Near Wallasey pool, Seacombe, April, 1857.

A. duplex, Donk.—New Brighton sands, September, 1858.

A. vitrea, Sm.—Eastham marsh, September, 1858; New
Brighton sands, September, 1857.

A. pusilla, Greg.— New Brighton sands, September, 1858.

‘A, complexa, Greg.—Great Float, April, 1858.

AMPHIPLEURA, Kiitzing.

A. sigmoidea, Sm.—Great Float, April, 1858—Canning Grav-

ing Dock, August, 1857, R. Daw.
Navicu.a, Bory.

N. rhomboides, Ehr.— Bridge at Spital, May, 1857.

N. lanceolata, Kiitz.—Bidston marsh, May, 1856.

N. cuspidata, Kiitz.—R. Fender, Bidston marsh, June, 1856.

N. Liber, Sm.—Great Float, April, 1858—Canning Graving
Dock, August, 1857, R. Daw.

N. firma, Kiitz.— Not unfrequent, but always occurs sparingly.
Rock in the Dingle, March, 1857, &c.

N. estiva, Donk.—New Brighton, September, 1858.

N. elliptica, Kiitz.-—Common.

N. pygmea, Kiitz.—Seacombe, April, 1851; Primrose hill,
New ferry, July, 1856.

N. Jennerii, Sm.—Bidston marsh, October, 1857; Seacombe,
April, 1858; Southport sands, August, 1858, &c.

N. Westii, Sm.—Seacombe, April, 1858.

N. convexra, Sm,—New Brighton sands, September, 1858.

N. elegans, Sm.—Pretty frequent in brackish water. Wal-
lasey pool, Seacombe, April, 1856; Bidston and East-
ham marshes, &c.

116 PROCEEDINGS OF SOCIETIES,

N. palpebralis, Bréb.—New Brighton sands, September, 1858,

N. Semen, Kiitz.—R. Alt, near Sefton, July, 1857.

N. affinis, Khr.—Wall on Dingle shore, March, 1857; rail-
way bridge, Spittal, May, 1857.

N. inflata, Kiitz.—R. Alt, near Sefton, July, 1857.

N. gibberula, Kiitz.—Frequent, but always much mixed with
other diatoms.

N. amphirynchus, Ehr.—R. Alt, near Sefton, July, 1857—
Storeton, June, 1856, L. H.

——Var. [3.—F requent, generally in brackish water.

N. spherophora, Kiitz.—Hoylake, October, 1856, G. M. B.

N. tumens, Sm.—Bidston marsh, July, 1856; October, 1856;
and October, 1857.

N. punctulata, Sm.—Primrose hill, New ferry, July, 1856;
Eastham marsh, September, 1858.

N. pusilla, Sm.—Sands at Great Meols, May, 1857; Bidston
marsh, October, 1856, and October, 1857.

N. tumida. Sm.—Moss at Rock ferry, October, 1857.

N. dicephala, Kiitz.— Birkdale marsh, June, 1858, G. M. B.

NV. cryptocephala, Kiitz.—Bidston marsh, May, 1857; rock at
Storeton, March, 1857, &c.

N. lineata, Donk.—New Brighton sands, September, 1858.

N. didyma, Kiitz.— Frequent, Bidston marsh, Oct. 1857, &c.

N. binodis, Ehr—Thornback pool, Crosby, September, 1856;
Hoylake, October, 1856, G. M. B.

N. levissima, Kiitz—'Lhornback pool, Crosby, September,
1856—Southport, June, 1857, G. M. B.

N. pectinalis, Bréb.—Sands at Great Meols, May, 1857, R,
Fender, Bidston marsh, August, 1858; Dee marsh, near
Queen’s ferry, June, 1858.

N. retusa, Bréb.—New Brighton sands, September, 1858;
Southport sands, August, 1858, G. M. B.

N. Lyra, Yhr.—Seacombe, April, 1858; Southport sands,
August, 1858.

N. humerosa, Bréb.—Sands at Great Meols, May, 1857; New
Brighton sands, Sept. 1858; Southport marsh, June, 1857.

N. Trochus, Greg.—Hoylake, October, 1856, G. M. B.

N. lacustre, Greg. —River Alt, Sefton, July, 1857.

—— var. [3, with var. a.

N. quadrangularis, Greg.—New Brighton sands, April, 1858 ;
Leasowe sands, October, 1858; Southport sands, Au-
gust, 1858, G. M. B. Generally much elongated, with
a curved median line.

N. apiculata, Bréb.—Southport sands, August, 1858.

PiInNULARIA, Ehrenberg.
P. major, Sm.—Storeton, June, 1856, L. H.

PROCEEDINGS OF SOCIETIES. dvi

viridis, Sm.—Common. Patrick’s well, Spital, &c.

. oblonga, Sm.—Well in Brombro’ woods, May, 1857; well

at Moreton, Cheshire, May, 1857.

. distans, Sm.—New Brighton sands, April and Sept. 1858.

. peregrina, Khr.—Very common in brackish water.

acuta, Sm.—Bidston marsh, October, 1856; Rock ferry,

March, 1857.

. directa, Sm.—New Brighton, October, 1858.

. radiosa, Sra.—F requent. Bidston marsh, &c.

. gracilis, Ehr.—Common in Bidston marsh, and other

brackish water localities.

P. viridula, Sm.—Bidston marsh, July, 1856.

P. Cyprinus, Ehr—Common in many localities subject to
marine influence.

P. Johnsonii, Sm. var. [3.—Bootle shore, Dec., 1858, G. M. B.

P. stauroneiformis, Sm.—Hoylake, October, 1856, G. M. B.
Highfield, L. H.

P. mesolepta, Ehr.—Patrick’s well, Spital, March, 1856; well
at Moreton, Cheshire, May, 1857, &c.

P. interrupta, Sm.—Storeton, June, 1856, L. H.

—— var. [3.—Storeton, June, 1856, L. H. Bidston
marsh, October, 1856.

P. borealis, Ehr.—Thornback pool, September, 1856; Moss
at Rock ferry, October, 1857.

P. integra, Sm.—Not uncommon. Thornback pool, Sep-

tember, 1856; River Alt, near Sefton, July, 1857, &c.

STrauroners, Khrenberg.

S. Phenicenteron, Khr.—Not uncommon. Well in Brombro’
May, 1857, &c.

S. gracilis, Ehr.—Well at Moreton, May, 1857; Storeton,
June, 1856, L. H.

. acuta, Sm.—Well in Brombro’ woods, May, 1857.

. salina, Sm.—Seacombe, April, 1858.

. erucicula, Sm.—Wallasey pool, April, 1856; and April,
1857 ; Southport marsh, June, 1857.

. anceps, Khr.—Not uncommon. Rock ferry, March, 1857;
well at Moreton, May, 1857, &c.

. linearis, Ehr.—Thornback pool, Crosby, September, 1856;
Moreton well, May, 1847.

. pulchella, Sm.—New Brighton, September, 1858 ; South-
port sands, August, 1858, G. M. B.

var. (Navicula angulata, Bréb.) New Brighton

sands, May, 1859.

PLEUROSIGMA, Smith.

P. rigidum, Sm.—Southport sands, August, 1858, G. M. B.
VOL. VIII. K

Oey eho se

RR RAM

(Pa)

118 PROCEEDINGS OF SOCIETIES.

elongatum, Sm.—Bidston marsh, July, 1856, and October,
1857; Southport sands, August, 1858.
. intermedium, Sm.—Bootle, December, 1858, G. M. B.
. delicatulum, Sm.—Bidston marsh, May, 1856, L. H.
. strigosum, Sm.—New Brighton, April, 1848.
. angulatum, Sm.—F requent. Bidston marsh, several times;
Primrose hill, &c.
. Lstuarii, Sm.—Southport sands, August, 1858; New
Brighton sands, September, 1858.
. obscurum, Bidston marsh, May, 1856, L. H.
. Balticum, Sm.—Bidston marsh, October, 1857; Eastham
marsh, September, 1858.
. Wansbeckii, Donk. (P. Balticum var. 3. Sm.)—Southport
sands, August, 1858. .
. strigilis, Sm.—Bidston marsh, October, 1857.
. acuminatum, Sm —Primrose hill, July, 1856; Bidston
marsh, October, 1857.
. Fasciola, Sm.—Primrose hill, July, 1856; Bidston marsh,
October, 1857 ; Eastham marsh, September, 1858, &c.
. macrum, Sm.—Bidston marsh, October, 1857.
. tenuissimum, Sm.—Wallasey pool, near Spital, April, 1858.
. littorale, Sm.—Primrose hill, July, 1856.
Hippocampus, Sm.—Not uncommon. Bidston marsh ;
Ditton marsh, &c.
. attenuatum, Sm.—Brook near Shotwick, Cheshire, June,
1858.
P. lacustre, Sm.—Not unfrequent. River Alt, near Sefton,
July, 1857, &c.
P. Spencerii, Sm.—Storeton, June, 1856, L.H.; River Fender,
June, 1856; Canal bridge over River Alt, June, 1857.
P. lanceolatum, Donk.—New Brighton sands, Sept., 1858.
P. marinum, Donk.—New Brighton sands, September, 1858.
ToxonipEA, Donkin.
T. Gregoriana, Donk.—Southport sands, Aug. 1858, G. M.
B.—Stomach of Noctiluca, Southport, Aug. 1858, T. S.
S. insignis, Donk.—Stomach of Noctiluca, Southport,
August, 1858, T. 8. '
Synepra, Ehrenberg.
S. pulchella, Kiitz.—Wallasey pool, April, 1857 ; Southport
marsh, June, 1857.
S. minutissima, Kiitz.—“ Birkenhead, Cheshire. G. Shadbolt,”
Sm. Synops.
S. radians, Sm.—Almost universally present in fresh-water
gatherings.
S Ulna, Ehr—Common, though not so much so as the last.

mitt oy

mow ty tut ty OD

PROCEEDINGS OF SOCIETIES. 119

S. Oxyrynchus, Kiitz.—Bidston marsh, October, 1857.
S. obtusa, Sm.—Thornback pool, Sept., 1856; Moreton well,
May, 1857.
8. capitata, Ehr—Hoylake, October, 1856,.G. M. B.—
Bidston marsh, October, 1857.
S. tabulata, Kiitz.—R. Fender, June, 1856; Dee Marsh, near
Queen’s ferry, June, 1858.
S. affinis, Kiitz—Bidston marsh, October, 1857.
S. Arcus, Kiitz—Dingte bay, February, 1857; Rock ferry
slip, February, 1857, L. H.
Cocconema, Ehrenberg.
C. lanceolatum, ¥hr—Frequently. Well in Brombro’ woods,
May, 1857, &c.
C. cymbiforme, Hhy.—Frequent. Rock in Dingle, March, 1857.
C. Cistula, Ehr.—Canal bridge, over R. Alt, June, 1857.
C. parvum, Sm.—Rock in Dingle, March, 1857.
Doryrnora, Kutzing.
D. Amphiceros, Kiitz.—Sparingly in many localities subject
to marine influence. New Brighton sands, Sept. 1858.

GomPuonema, Agardh.
G. geminatum, Ag.—Patrick’s well, March, 1856, L. H.
G. constrictum, EKhr.—Frequent. Rock ferry, March, 1857, &e.
G. acuminatum, Ehr.—Frequent. Well at Moreton, May,
1857, &c.
G. cristatum, Ralfs.—Canal bridge over R. Alt, June, 1857.
G. dichotomum, Kiitz.—Well at Moreton, May, 1857.
G. tenellum, Sm.—Frequent. Rock ferry, March, 1857, &c.
G. capitatum, Ehr.—Var. y. Well at Moreton, May, 1857.
G. oliwaceum, Khr.—Rock ferry, March, 1657.
G. intricatum, Kiitz.—Rock in Dingle, March, 1857.
G. curvatum, Kiitz.—Frequent. Sefton lock, July, 1857, &c.
RuiprpopHora, Kutzing.
R. Dalmatica, Kitz.—Dingle bay, February, 1857..
Meripion, Agardh.
M. circulare, Ag.—Not unfrequent, but alwaysmuch mixed with
otherdiatoms. Near Wallasey pool, Seacombe, A pril, 1856.
BaciLuARia, Gmel.

B. paradoxa, Gmel. In most brackish localities. Bidston,
Eastham, Ditton, and Dee marshes.
B. cursoria, Donkin.*—Sands at New Brighton, Sept. 1858.

_ * In my specimens the F.V. is always presented to the eye when in the
living state. I consequently name it with a little doubt; it is certainly not
. B. paradoza.

120 PROCEEDINGS OF SOCIETIES.

Himantipium, Ehrenberg.

H. pectinale, Kiitz. Frequent. Well at Storeton, March.
1857, &c.

H. undulatum, Sm.—Well at Storeton, March, 1857.

H. Soleiroli, Kiitz—Well at Storeton, March, 1857.

H. gracile, Ehr.—Rather common. Bidston marsh, May,
1856; rock in Dingle, March, 1857, &c.

OpontipiuM, Kiitzing.

O. mutabile, Sm.—Patrick’s well, Spital, March, 1856; Skew
bridge, Bebbington, May, 1857; railway bridge, Spital,
May, 1857. ;

O. parasiticum, Sm.—Bidston marsh, October, 1857; in
Rivington Pike water supplied to the town.

DenTICcULA, Kiitzing.

D. obtusa, Kiitz.—Canal bridge over R. Alt, June, 1857.

D. sinuata, Sm.—Railway bridge, Spital, May, 1857; rock
in Dingle, March, 1857; canal bridge over R. Alt,
June, 1857.

’ FRAGILLARIA, Lyngbye.
F. capucina, Desm.—Rock ferry, March, 1857; a curious

variety from Bidston marsh, October, 1857.
F. virescens, Ralfs.—Patrick’s well, March, 1856.

Eucampra, Ehrenberg.

F. zodiacus, Ehr.—Rock ferry slip, July, 1856—Stomach of
Noctiluca, Southport, August, 1858, T. S.

ACHNANTHES, Bory.

A. longipes, Ag.—New Brighton, March, 1857, L. H.
Canning Graving Dock, July, 1857, R. Daw.

A. brevipes, Ag—Common in the Mersey. Rock ferry slip,
July, 1856; Dingle Bay, February, 1857, &c.

A. subsesslis, Kiitz.— Bidston marsh, May, 1856; July, 1856;
and Oct. 1857.

A. ezxilis, Kiitz—Rock in Dingle, March, 1857; railway
bridge, Spital, May, 1857; canal bridge over R. Alt,
June, 1857.

ACHNANTHIDIUM, Kiitzing.

A. lanceolatum, Bréb.—Not uncommon. Rock near Storeton,
March, 1857, &c.

A. coarctatum, Bréb.—Skew bridge, Bebbington, May, 1857;
moss from Rock ferry, October, 1857.

A. microcephalum, Kiitz.—Canal bridge over R. Alt, June, 1857.

PROCEEDINGS OF SOCIETIES. 12h

RHABDONEMA, Kiitzing.

A. arcuatum, Kiitz.— Woodside slip, May, 1857; New
Brighton, February, 1857, L. H.

ft. minutum, Kitz.—Dingle bay, February, 1857—Rock
ferry slip, February, 1857, L. H.

STRIATELLA, Agardh.
S. unipunctata, Ag.—Primrose hill, New ferry, July, 1856.
Diatoma, Dec.

D. vulgare, Bory—Common. Canal near Aintree, June,
1858, &c.

D. elongatum, Ag—Common. Generally in brackish water.

Var. [(3.—Hoylake, October, 1856, G. M. B.

Var. y.—Aintree, June, 1857.

GramMaAToPHORA, Ehrenberg.

G. marina, Kutz.—New Brighton, February, 1857, L. H.—
Woodside slip, May, 1857.

G. serpentina, Kiitz—New Brighton, April, 1857.

TaABELLARIA, Ehrenberg.

x Sapa Kiitz.— Well opposite Bebbington Church, July,

1850.

—

Brippuupuia, Gray.

B. aurita, Bréb.—R. Fender, June, 1856—Southport sands,
August, 1858, G. M. B.

BL. Rhombus, Sm.—Common. New Brighton, frequently ;
Leasowe, Southport, and Hoylake.

B. Bailey, Sm.—New Brighton, April and October, 1858—
Stomach of Noctiluca, Southport, August, 1858, T. S.

B. turgida, Sm.—Leasowe, September, 1858, G. M. B.

B. granulata, Rop.—New Brighton, April, 1858—Leastowe
September, 1858, G. M. B.

Poposira, Ehrenberg.

P. Montagnei, Kitz —Common.—Bidston marsh, Southport,
&e.
P. maculata, Sm.—Not uncommon. New Brighton, &c.

Me vosira, Agardh.

M. nummuloides, Kiitz.—Common. R. Mersey, frequently ;
Dee marsh, near Queen’s ferry, June, 1858.
M. Borreriit, Grev.—Bootle shore, December, 1858, G. M. B.
M. varians, Ag —Extremely common.
M. Westii, Sm.—Bidston marsh, October, 1857.
Ortuosira, Thwaites.

O. marina, Sm.—New Brighton, several times.

122 PROCEEDINGS OF SOCIETIES.

O. orichalcea, Sm.—Bidston marsh, October, 1856; well at
Sefton, July, 1857; and June, 1858.
Mastroc.toia, Thwaites.
M. lanceolata, Thw.—Southport marsh, June, 1857; Birk-
dale marsh, June, 1857, G. M. B.
M. Smithii, Thw.—Birkdale marsh, June, 1857. G. M. B.

Encyonema, Kiitzing.

L. prostratum, Ralfs.—Sefton lock, July, 1857; canal bridge,
over R. Alt, June, 1857.

CoLLETONEMA, Brébisson.
C. eximium, Thw.—Bidston marsh, October, 1857.
C. vulgare, Thw.—Storeton well, March, 1857.
C. neglectum, Thw.—R. Alt, near Sefton, July, 1857; R.
Fender, Bidston marsh, August, 1858.
Scu1zoNeMA, Agardh.
S. cruciger, Sm.—Bidston marsh, May, 1856; New Brighton,
February, 1857; Canning Graving Dock, August, 1858.
S. helmintosum, Chauv.—Rock ferry slip, February, 1857,
L. H.—Dingle Bay, February, 1857.
S. Smithii, Agardh.—Rock ferry slip, February, 1857—New
Brighton, March, 1857, L. H.
S. Grevillii, Agardh.—New Brighton, March, 1857, L. H.;
and October, 1856, G. M. B.
Homaocrapia, Agardh.
Hl. filiformis, Sm.—Canal bridge over R. Alt, June, 1857—
Canal at Aintree, June, 1858, L. H.
H. sigmoidea, Sm.—Pit at Aintree, June, 1857; Bidston
marsh, October, 1857.

ASTERIONELLA, Hassall.

A. formosa, Hass.—In Rivington Pike water supplied to the
town.

123

ZOOPHYTOLOGY.

Descriptions of New Sprxctes of Potyzoa. Collected by
GeEorRGE Barer, Esq., in Shetland.

THE assiduous dredging labours of Mr. Barlee, more espe-
cially in the Northern seas of Scotland, have, as is well
known, been the means of introducing numerous additions
to the British Marine Fauna, among which, those belonging
to the domain of Zoophytology are by no means the least
considerable. Having been favoured by Mr. Barlee with the
opportunity of examining the Polyzoa collected by him,
within the last two years, we here commence the description
of the new or imperfectly known species comprised among
them. As these are numerous, and our limits, so far as
illustrations are concerned, circumscribed, the description of
these species will occupy several numbers of the journal,
although, in the meanwhile, brief descriptions of most of the
new forms were presented to the British Association at its
late meeting.

Sub-order. Cheilostomata.
Fam. 1. Flustride.
Gen. 1. Flustra. Linn.
1. F. Barlei, nu. sp. Pl. XXV, fig. 4.

TF. polyzoario foliaceo, diviso, lobato ; cellulis oblongis, margine simpliet ;
ovicellults cucullatis ; aviculariis intercellulas sparsis, oblique positis, man-
dibulo semicirculart.

Cells oblong, with a simple margin; ovicells shallow, cucullate ; avicularia
few, scattered, placed obliquely, and having a semicircular mandible. Poly-
zoarium foliaceous, divided, lobate.

Hab. Shetland, Barlee.

The polyzoarium of this species bears a close resemblance
to some conditions of Flustra foliacea ; but, when examined, it
will at once be seen to be wholly distinct from that and all
other hitherto described species. The cells are of the same
oblong, rectangular shape as those of FP. papyracea and F.
truncata, and, as in those species, wholly membranous in
front. F. Barlei differs, however, from both, in the far
larger size of the cells, which is at least double that of the
cells in either of the species named. The margin is wholly

124 ZOOPHYTOLOGY.

unarmed, as in F, truncata, from which F. Barlez, is however
distinguished, not only by the far smaller dimension of the
cells, but also by the oblique position of the avicularia, and
the widely different habit of its growth. fF. papyracea,
besides its having a small marginal spine on each upper
angle, has no avicularia, so far as [ am aware, and also differs
from F. Barlei very widely in habit.

This is an important addition to the British Zoophy-
tological Fauna; and it is curious that so large and well-
marked a species should have hitherto escaped recognition.

Fam. 2. Membraniporide.
Gen. 2. Membranipora. Blainv.
1. MW. cornigera, nu. sp. Pl. XXV, fig, 2.
M. incrustans ; cellulis pyriformibus, superne angustatis, margine glabro

spinis 6 armato quarum infimis bifurcatis ; lamind subgranulosd. Aviculariis
crebris, inter cellulas sparsis, mandibulo semictreulart instruetis.

Incrusting; cells pyriform, contracted above, expanded below, with a
smooth margin armed with three pairs of spines, of which tie lowest are
forked; lamina subgranular. Avicularia numerous, interspersed among the
cells, with a rounded or semicircular mandible.

Hab. Shetland, Barlee.

When in a state of tolerable preservation, no confusion
can be made between this species and any other. Its nearest
ally, perhaps, is M. Flemingii, in which the form of the cell
is pretty nearly the same, and the number of marginal spines
equal; but the disposition of the aivcularia differs, so that
even in much worn specimens, sufficiently distinct characters
may in most cases be perceived. When the marginal spines
are uninjured, the peculiar forked form of the lowest pair
will at once suffice to distinguish the present from any
other British species. In M. Flemingii also, the mandible of
the avicularium is acutely pointed, whilst in M. cornigera it
is rounded and obtuse. ,

M. vulnerata,n. sp. Pl. XXV, fig. 3.

MM. incrustans ; cellulis subpyriformibus seu ovalibus, superné angustatis ;

a” 46 a” et Pa * nn . “

apertura parvd, semicirculariad ; lamind granulosd, utrinque fissurd sigmoided
plerumque ornatd ; margine granulosd, inermi ; vibraculis intercellulas sparsis.

Incrusting; cells subpyriform or suboval; aperture small, semicircular
lamina granular, usually with a narrow sigmoid slit on either side; margin
granular, unarmed. Vibracula scattered among the cells.

Hab. Shetland, Barlee ; on stone.

This, so far as I am aware, is the only Membranipora
furnished with vibracular instead of avicularian organs.

ZOOPHYTOLOGY. 125

3. M. minaz,n. sp. Pl. XXV, fig. 1.

M. adnata ; cellulis pyriformibus inferné angustatis ; area ovali, apertura
trifoliatd ; lamind glabra ; margine tenui spinis elongatis, gracilibus, 4
armato. Aviculario magno, sessili,in parte anteriori cellule, medio posito,
mandibulo, rostroque peracutis ; ovicellulis rotundatis, magnis.

Adnate; cells pyriform, contracted below; area occupying about half the
front of the cell of an oval form, with asmooth thin margin armed with four
slender, elongated spines ; lamina smooth; aperture obscurely trifoliate in
form. A large, prominent, (but not pedunculate,) avicularium placed on
the middle of the cell in front, below the area,and having a very acute

mandible and rostrum, which are placed transversely ; ovicell rounded, pro-
minent.

Hab. Shetland, Barlee ; on stone.

The strong, prominent avicularium is a striking charac-
teristic of this species. Its mandible and rostrum are both
pointed, and the organ is placed transversely with respect to
the axis of the cell.

Gen. 3. Lepralia. Johnst.
1. L. sinuosa,n.sp. Pl. XXIV, figs. 2 and 3.
L. cellulis subrhomboideis, subplanis, lined elevatd, sinuosd sejunctis, porosis;
orificio suborbiculari, infra sinuato, peristomate tenui, elevato.
Cells subrhomboidal, flattened in front, perforate, separated by a wavy,
sinuous line ; orifice suborbicular, sinuated below; peristome thin, raised.
Hab. Shetland, Barlee ; on shell. Cornwall, Peterhead, Ipswich. Peach.

My friend Mr. C. Peach is of opinion that this species is identical with
one found by him in thie localities above cited, and described with a figure
in the “ Report of the Royal Institution of Cornwall for 1851,” But I

must confess that his figure leads me to doubt the correctness of Mr.
Peach’s surmise.

2. L. Malusii, Audouin.
Var, Spinis marginalibus armata.

In the ‘ Brit. Mus. Catalogue,’ L. Malusu is placed among
the unarmed species, but subsequent observation has shown
that the form furnished with marginal spines, there cited as
a variety, may be more properly regarded as the typical
aspect of L. Malusii, of which a figure is here introduced,
taken from a specimen, in which the mode of origin of a patch
from a single, central, abnormal cell is well shown.

ZOOPHYTOLOGY.

DESCRIPTION OF PLATES XXIV & XXV.

PLATE XXIV.
Fig.
1.—Lepralia malusii, p. 125.
9— ,, . simuosa, X 25 d., p. 125.
3— » as x 50d.

PLATE XXV.

1.—Membranipora rhynchota, p.- 125.
a. Avicularium, open.
b. bs closed.
2.—WM. cornigera, p. 124.
3.—WM. vulnerata, p .124.
4.—Flustra Barlei, p. 123.
a. Natural size of small fragment.
4. Avicularium, xX 50 d.
c. Portion, X 25. d.
5.—F’, truncata

6.—F. papyracea } x 25 d., for comparison.

ZOOPHYT OLOGY.

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ORIGINAL COMMUNICATIONS.

On American Diatomacex. By Artuur M. Epwarps, Esq.,
New York, U.S.

A paPeR of mine, on American Diatomacex, was read
before the London Microscopical Society, March 30th, 1859,
and published in their Transactions, in which an omission
occurred which I herein wish to rectify. A mistake occurred
in re-writing, so that the description of the species found at
Charleston harbour, 8S. C., was left out. A paper on this
subject, by the present writer, was read before the New York
Lyceum of Natural History, February 21st, 1859, a copy of
which is annexed :-—

On the Microscopic forms of the Harbour of Charleston, South
Carolina.

In the year 1850, Professor Bailey published in the ‘Smith-
sonian Contributions to Knowledge,’ a list of the microscopic
organisms which he had found in mud collected from the logs
of wharves, and from other situations in the harbour of
Charleston, 8. C., which contained two new species, besides
many other curious forms; and in the year 18538, he de-
scribed four species of Ehrenberg’s genus Auwliscus, three of
which are also found at Charleston, though Bailey failed to
detect them. Bailey’s list is as follows :—

Actiniscus sirius, hr. Navicula sigma, Ehr.

Actinoyclus bioctonarius, Lhr.
Actinoptychus senarius, hr.
Biddulphia pulchella, Gray.
Cocconeis scutellum, hr.

Coscinodiscus eccentricus, LAr.

Dictyocha fibula, Zir.

boas Rogersii, Hhr.
radiatus, B.

* Gaill?nella suleata, Hhr.

Pinnularia interrupta, HAr.
af didyma, hr.

C lyra, Lhr.
Raphoneis rhombus, Zhr,
Stauroptera aspera, Lhr.

*Surirella cireumstuta, B.
Terpsina musica, LAr.
Triceratium favus, hr.

ee alternans, 2.

Certain of these have been re-named by later observers,

VOL. VIII.

L

128 EDWARDS, ON AMERICAN DIATOMACEZ.

or have been found to be synonymous with already described
species, and should be designated thus :—

Actinocyclus bioctonarius, Pr.
Actinoptychus senarius, Zhr.
Eupodiscus Rogersii, Lhr.
Pinnularia didyma, Ehr.

es lyra, Lhr.
Raphoneis rhombus, Zur.
Stauroptera aspera, [hr.
Surirella circumstuta, B.
Gaillionella suleata, Phr.

Coscinodiscus actinoptychus, Zdw.
Actinopheenia splendens, Shad.
Kupodiscus argus, Lhr.
Navicula didyma, X.

ps Ayres
Doryphora amphiceros, KX.
Stauroneis pulchella, W. S.
Tryblionella scutellum, VW. S.
Orthosira marina, Hhr.

Hui uo da dea

Actiniscus sirius, Ehr., and Dictyocha fibula, Ehyr., are
neither of them Diatoms, and are most probably portions of
the skeleton of a Holothuria.

Some two years back, I received from a friend residing at
Charleston some of the so-called black “ pluff”’ mud, taken
from between watermarks, and which I found to be extremely
rich in Diatomaceous forms. The following species were
observed :—

Actinocyclus undulatus, Zhr. Epithemia Hyndmanii, W. S.
Actinopheenia splendens, Shad. * musculus, K.
Auliscus celatus, B. Navicula didyma, K.

» pruinosus, B. eer maculata, 2. sp.

» punctatus, 2B. permagna, 2. sp.
Biddulphia rhombus, V7. S. “NitZachia scalaris, W. S.

Pn aurita, Bréb. Pleurosigma angulata, W.S.
Campylodiscus cribrosus, W. 8. Triceratium alternans, B.
Cocconeis scutellum, hr. favus, Ehr.
Coscinodiseus actinoptychus. Hdw. punctatum, 7. B.

55 eccentricus, Lhr. Tryblionella seutellum, VS.
3 lineatus, Lhr. 4 punctata, WS.
ms oculus-iridis, Zhr.

* radiatus, Hhr.

3 subtilis, Hhr.

The Navicula sigma, Ehr., of Bailey’s list, is most probably
synonymous with the Pleurosigma angulata, W.S., of mine.
Those species marked with an asterisk (*) are new, and are
characterised as follows :—

Navicula maculata, n. sp.=Stauroneis maculata, B., 1850.

“Tanceolate or elliptical; ends slightly produced and
rounded ; surface punctato-striate, with a lar ge smooth cen-
tral space.” Bailey. To this description I haveto add a
following measurements : length -055 in. ; breadth ‘00216 in.
strize coarsely moniliform, 12 in. ‘001 re

Navicula permagna, n. sp.=Pinnularia permagna, B., 1850.

“Large, lanceolate on the ventral faces, with punctato-
striate marginal bands, and a broad, smooth central stripe ;

EDWARDS, ON AMERICAN DIATOMACE. 129

ends slightly rounded.” Bailey. I have as yet only found
this species in small quantities, and have been unable to
make its measurements. There can be no doubt that these
two species should be placed in the genus Navicula, as the
seeming stauros in the first, the presence of which would
seem to rank it in that of Stauroneis, is only a blank space,
such as is seen in many species of Navicula, as N. elegans,
&c. The presence of moniliform striz in the second species
removes it from Pinnularia, which is characterised by its
markings being coste, not resolvable into dots. Of N.
macuiata, | have specimens from Duval’s Creek, near Enter-
prise, Florida, for which I am indebted to Dr. Christopher
Johnston, of Baltimore, Md.

I here mention a fact that has come within my notice
while examining this gathering. Smith’s Kupodiscus radiatus,
as described and figured in the first volume of his ‘ Synopsis,’ is
not the same as the form described under that name by
Bailey in 1850. Roper has remarked this same fact (‘‘Trans. |
Mic. Soc.,’ London, vol. vii, p. 19), but was in some doubt
until I had the pleasure of forwarding him authentic
specimens of it from Bailey’s cabinet, when he wrote to me
that the examination of them confirmed his opinion that
Smith was in error in referring the Thames diatom to that
species. It is perfectly distinct, and a true Eupodiscus.

Since the above article was written, I have been lead, by
the advice of Dr. Arnott, to reconsider the subject of the
species, which I, in my paper on American Diatoms, called
Coscinodiscus actinoptychus. This belongs to Ehrenberg’s
genus Actinocyclus, the species of which are characterised by
the number of rays,—a loose character. It should therefore
be placed in that genus for the present, the specific name
being left blank until more is known of its natural history.

130

TRANSLATION.

ArmosPHERIC MicrocrarpHy. OssEervatTions on the Cor-
PUSCLES suspended in the AtMosPHERE. By M. Povucuer.

(‘ Comptes rendus,’ March 21st, 1859.)

THE atmosphere contains, in suspension, numerous cor-
puscles, consisting of the detritus of the mineral crust of the
earth, animal and vegetable particles, and the minutely
divided débris of the various articles employed in our wants.
These various kinds of corpuscles are more numerous and
more voluminous in proportion to the degree in which the
atmosphere is agitated by the wind; and they constitute
what we term “ dust.”

This ‘ dust”? being simply the deposit of the corpuscles
carried in the atmosphere, it is evident that the attentive
study of its composition is simply a microscopic analysis of
the air.

The granules of mineral origin, partly going to form the
dust, present but little variety. They are derived essentially
from the detritus of the rocks which are exposed in the
country where the dust is observed.

The débris derived from the animal kingdom consists
chiefly of the following articles :—various animalcules in a
dry state and of extreme minuteness, such as entozoa be-
longing to the genus Oxyuris and Vibriones of several
species. I have often also noticed the skeletons of siliceous
Infusoria, especially of Navicule, Bacillarie, and other
diatoms; fragments of the antennze of Coleoptera; scales of
diurnal and nocturnal Lepidoptera; fibres of wool of various
colours derived from our clothes, often of a beautiful blue,
bright red, or green; hairs of the rabbit, bat, &c.; the
barblets of feathers; fragments of the tarsi of imsects ;
epithelial cells; fragments of the skin of various insects ;
particles of cobweb. ‘Twice only, in more than a thousand
observations, have I observed one of those large ova of
Infusoria having a diameter of 0°0150mm., denominated by
naturalists ‘ cysts.”

The corpuscles contained in “ dust’? belonging to the vege-
table kingdom, observed by me, are the following ;—frag-

POUCHET, ON ATMOSPHERIC MICROGRAPHY. 131

ments of the tissue of various plants; a few ligneous fibres ;
more frequently fragments of cells and vessels ; often hairs of
the nettle and other plants; numerous filaments of cotton,
usually white, but sometimes of various colours, also derived
from articles of dress; some fragments of anthers and pollen-
grains of malvaceous plants, of Epilobium and Pinus ; spores
of cryptogamous plants, but in very small number. Lastly,
I have constantly noticed, and almost invariably where my
observations have been extensive, a very notable quantity of
wheat-starch mixed with the dust, whether recent or old;
and, in rare instances, may be found the starch of oats,
barley, and the potato.

It is evident, therefore, that the atmosphere holds in sus-
pension a certain quantity of wheat-starch among its dust-
corpuscles. This substance is met with in all places where
it enters into articles of food, and it may readily be distin-
guished by its physical and chemical characters. The grains
of which it consists are sometimes ovoid, sometimes spherical ;
in diameter they usually vary from 0:0140 to 0:0280mm.
Besides these numerous extremely minute incipient granules,
may be seen others less than 0-0028mm. in diameter. The
larger grains are very rare; those of a medium size far
more common, and the very minute ones extremely abundant.
In the large granules the concentric layers and hilum may
sometimes be readily distinguished. It is rather curious to
remark that this starch, notwithstanding, in some instances,
its secular existence, still affords all the physical and chemical
properties of the recent substance. The only difference
being that the very ancient presents a light-yellow tint.
When boiled in water it swells and dissolves. Very weak
hydrochloric acid has no effect upon it; it is coloured blue
by iodine with greater or less intensity; and sometimes its
colour disappears under the influence of light. One circum-
stance which has struck me, is, that among starch found in
dust several centuries old, I have, from time to time, met
with grains which had spontaneously assumed a beautiful clear
violet colour. Was this due to the influence of time, or to
the vicinity of the sea, or, lastly, according to M. Chatin, to
the traces of the vapour of iodine contained in the atmo-
sphere? Finally, that no doubt may be entertained with
respect to the identity of this aérial fecula with ordinary
starch, I would add, that its effect upon polarized light is
the same, except that, when procured from a very ancient
deposit, its polarizing property is less energetic.

It is evident that it is this fecula thus perfectly charac-
terised by its physical and chemical properties, that M. De

132 POUCHET, ON ATMOSPHERIC MICROGRAPHY.

Quatrefages has taken for the ova of microzoa. It is the
most minute grains of this substance to which he refers when
he states, that he “ could easily recognise in the dust” several
of those minute corpuscles of a spherical or ovoid form, well
known to all micrographers, and which involuntarily suggest
the idea of an extremely minute ovum.* This image is
correct, but the illusion is at once dissipated by the slightest
chemical test, which proves that the granules in question
can be nothing else than either extremely fine amylaceous
grains or siliceous particles, which I have frequently ob-
served, and which are of such extreme tenuity, as under the
microscope to present the appearance of transparent spherical
granules.

Astonished at the comparative abundance of the amyla-
ceous particles which I found among the atmospheric cor-
puscles, and in order to obtain a rigorous demonstration of
the fact, I determined to examine dust of all ages and from
all localities. I have investigated the monuments of our
great cities, others on the sea-shore and in the desert; and,
in the midst of the immense variety of corpuscles universally
floating in the air, have almost everywhere met with starch
in greater or less abundance. Gifted with an extraordinary
self-conservative power, time seems scarcely to affect it.

However remote may be the antiquity of the atmospheric
corpuscles, starch still recognisable is found among them. I
have discovered its presence in the most inaccessible recesses
of our old Gothic churches mixed with the dust, blackened
by an existence of from six to eight centuries. I have even
found it in the palaces and subterranean chambers of the
Thebaid, where it would date probably from the epoch of the
Pharaohs.

It may be affirmed, as a general proposition, that in all
countries where wheat constitutes the basis of food, its
starchy element penetrates everywhere with the dust, and is
found mixed with it in more or less considerable quantity.
It is more abundant in situations pear the centre of towns
and at a low level, whilst, in proportion as we go to greater
distances from the great centres of population, and explore
the more isolated monuments, does the starch become less
and less abundant, and its grains more and more minute.
I have been unable to detect any either in the Temple of
Jupiter Serapis, situated on the shores of the Gulf of Baiz,
or in that of Venus Athor, placed on the confines of Nubia.
Nevertheless, I have collected some in subterranean temples
of Upper Egypt.

* «Comptes rend.,’ Paris, 1859, t. xlviii, p. 31.

POUCHET, ON ATMOSPHERIC MICROGRAPHY. 133

It is remarked also, that in proportion to the elevation
reached on mountains or on buildings, the amount of fecula
mixed with the atmospheric detritus is diminished. In the
Abbey of Fécamp, which is below the level of the ground,
and situated in the middle of the town, starch abounds in
the dust of its chapels. In the Cathedral of Rouen a con-
siderable quantity is met with in the lower part of the
tower of Georges d’Amboise, the proportion gradually dimi-
nishing as we ascend. Whilst still abundant in the ancient
dust found in the roof of the choir, it becomes more and
more rare when we mount into the spire. Very little is
found at the base of the cast-iron pyramid, and not a single
grain at its summit.

In an isolated chapel situated on the sea-shore, and built
on a beach about 110 metres in elevation, the dust lodged
on a statue was composed, in great part, of calcareous
particles, derived from the sides of the mountain, and con-
veyed by the wind to the floor of the building, which is open
day and night to pilgrims. In the same situation were also
found a great number of scales of lepidopterous insects, which
had, doubtless, often sought shelter there ; but very rarely was
a grain of starch perceived in the field of the microscope ;
whilst in the detritus of towns, on every trial, several grains
of a medium size, and a considerable number of more minute
dimensions, would have been noticed.

A battery also placed on the shore, and in an isolated situa-
tion, and which had not been opened for sixty years, afforded
a black dust, which was as poor in starch as that of the
chapel above mentioned. But the dust itself was of a wholly
different nature, being composed almost entirely of very
angular, transparent, colourless particles of silex. The
starch was so scarce in this dust, that often not more than
a single grain could be discovered in a dozen observations.

This dissemination is a phenomenon so general and so
widely diffused in places where wheat is used for food, that
there is no nook or corner into which starch does not in-
sinuate itself with the air. It is found in everything, and in
all situations into which the latter penetrates. The most
obscure corners of our Gothic buildimgs have afforded this
substance in the ancient dust which had never been dis-
turbed in the memory of man. I have even found it in the
interior of the eavity of the tympanum in the skull of a
mummified dog which I procured from a subterranean
temple in Upper Egypt. M. Ch. Robin, whose observations
accord with mine, has discovered starch on the surface of
the human skin, whence it may be procured by scraping

134 POUCHET, ON ATMOSPHERIC MICROGRAPHY.

with a sharp instrument either in the dead body or of a
living person.

All these observations, if it were needed, might be sup-
ported by biological proofs. Until the contrary can be
shown experimentally, it may be said that the air is so
rarely the vehicle of ova, and the dust so rarely their recep-
tacle, that when the latter is subjected to an elevated tem-
perature, it is no less fecund in animalcules than that which
has not been heated; which would not be the case, were the
hypothesis of aerian dissemination of ova founded in truth.

I have often repeated the following experiment. I have
taken 3 grammes of an ancient dust, and placed it in a
thin tube, heated to 215° C., in an oil-bath, for an hour and
a quarter. The dust has afterwards been put into 30
grammes of artificial water, and the whole covered with a
bell-glass. At the end of five days, and at a mean tem-
perature of 20° C., the water was crowded with animalcules of
large size—Colpoda and Paramecium. The same result takes
place with dust which has not been heated. What has been
taken, therefore, for ova deposited from the atmosphere, was
not really such; for, in that case, the dust which had been
heated would have been infertile, the germs contained in it
having been killed by a temperature of 215°C.

Another very simple experiment also proves that it is
impossible to discover any living germ in the atmosphere.
By means of an inhaling flask I caused 100 litres of air to
pass through a safety tube whose bulb contained two cubic
centimetres of distilled water. At.the end of eight days I
was unable to discover a single animalcule or ovum in this
small quantity of water, in which the latter, themselves, could
not escape observation, now that they have been completely
described and measured, and are well known in several species.
On the contrary, if I place in a cubic decimetre of distilled
water 5 grammes of a fermentable substance, sheltered
by a bell-glass having a capacity of one litre, at the end of
eight days, and at a temperature of 18° C., the whole surface
of the water is occupied by incalculable myriads of ani-
malcules.

The memoir concludes with the detail of particular observa-
tions on dust collected in the following localities :

Tower of Georges d’Amboise, at Rouen. Interior of the
Abbey at Fécamp. Ruins of Thebes. Tomb of Ramses II.
Sepulchral chamber of the Great Pyramid. ‘Temple of Venus
Athor, at Philoe. Temple of Serapis, at Puzzuoli. Skull of
a mummified dog, from the subterranean yaults of Beni-
Hassan. The cabinet of a Jewish antiquarian at Cairo.

135

NOTES AND CORRESPONDENCE.

Angular Aperture——My object in the paper on the subject of
angular aperture, which you were good enough to insert
(p. 256, last volume), was simply to facilitate the application of
Mr. Lister’s method of measurement, by showing how that
method might be made available independently of the special
apparatus usually considered requisite for this purpose. Mr.
Hendry, therefore (p. 61, present volume), is mistaken if he
supposes, as he seems to do, that I claim for the method, as
described by me, superiority in point of accuracy to the
method as usually practised. I do not do that, but I claim
for it equality im this respect. An angle is determined quite
as accurately by measurement of the sides of the triangle to
which it belongs, as by measurement of its subtending arc.
The use of two candles saves the trouble of moving the one
candle, if one only is used, from one side of the field of view
to the other; and the indication of these being properly
placed will easily be found to be in exact accordance with
the corresponding indication m Mr. Lister’s method, as
usually described.

But I am surprised at Mr. Hendry’s statement, that “ my
rule gave no provision for angles exceeding 90°.” I know of
no ground for this statement. Take his fourth example :

Lights apart, 44 inches; distance of lens, 10 inches.

Hence 44 + (10 x 2) = 2:2. On reference to Hutton’s
Tables, I find this to be the tangent of 65° 33’. The aperture
therefore is 131° 6’.

Mr. Hendry, perhaps, has only a table of logarithmic
tangents. Very well. The logarithm of 2-2 is 0°3424, to
which adding 10, to accommodate it to the tabular radius, it
becomes 10°3424; and this is the logarithmic tangent of
65° 33’, as before —M. Gray, 7, St. Paul’s Villas, Camden
Town, December 5th, 1859.

A New Cement for mounting Objects for the Microscope, either
in dry cells or in fluid—I have found that great rapidity is
obtained in mounting objects in a cement made with as-

136 MEMORANDA.

phaltum dissolved in Benzine or Benzole instead of turpentine,
because it dries so quickly that a great many more objects
can be mounted and finished in a day with it than with any
other cement. I finish it off with a coat of asphalt in tur-
pentine, to give it a smooth appearance.

It should be kept, like all cements for the mounting of
microscopic objects, in a capped bottle, so that the brush is
always soft and ready for use.

Benzole is also the most convenient solvent for removing
superfluous balsam from the outside of the glass covers under
which objects are mounted in that medium.—J. W. Law-
RANCE, Peterborough.*

Registration of Objects——I beg to subjoin notice of a simple
mode of registermg objects on slides, which was devised by
me in India, and has answered all ordinary purposes so effici-
ently as to induce me to hope it may prove useful to micro-
scopists.

It possesses three great advantages,—in requiring no sepa-
rate apparatus, no special adjustment of slides or stage, and
costing nothing. It is adapted for use with all the higher
powers of the microscope. Although more readily available
where the body of the instrument admits of lateral displace-
ment, it may nevertheless be used where no such arrange-
ment exists, by simply elevating the body to a sufficient
height to allow of the bearings of the spot of light given off
from the illuminator being accurately taken by the eye and
hand.

Suppose an object to be in the centre of the field of vision.
The body of the microscope is either turned aside or raised,
as the case may be. The slide being securely clamped in
position, two minute marks are made, with a writing diamond,
perpendicularly above, and in a line horizontal with, the spot
of light thrown upon the object by the condenser. The
smaller the spot of light, of course, the more easy will it be
to denote the situation of an object accurately. ‘The slide is
now removed, and the scratches are converted into short
vertical and horizontal lines, varying in length according to
convenience. ‘These two lines are now joined together by a
third line; and, lastly, a number is attached, at either angle
thus formed, for entry in the note-book or catalogue of the
observer.

To find the object again, all that has to be done is to place
the slide on the stage, and the body of the microscope being

* The addition of a little gold size to the solution of asphaltum in benzine
will be found useful in rendering it less brittle —[Eps.]

MEMORANDA. 713)

either turned aside or elevated as before, to move the slide to
and fro, either by hand or stage movements, until the spot of
light from the condenser indicates the spot at which the
vertical and horizontal lines beyond the margin of the cover
would intersect each other, if produced.

Of course, upon the accuracy with which the bearings have
been taken will depend the facility of finding an object. But
with ordinary care and a tolerably true eye, there is no diffi-
culty.

The following diagram will show the mode of registry, and
how it may be applied to any number of objects on the same
slide—

6

The dots, it is almost unnecessary to remark, are appended
merely with a view to indicate the points at which the objects
to be registered occur.—G. L. Watuicn.

Improvement of the Camera Lucida.—One of M. Nachet’s
ingenious applications of the prism to the microscope fur-
nishes a hint for the improvement of the camera lucida,
which I desire to bring under the notice of yourself and your
readers. I refer to the arrangement described and figured
on p. 706 of the second edition of Dr. Carpenter’s work on
the microscope. A prism of peculiar form is there seen, ap-
plied as a camera lucida to a vertical microscope.

To the arrangement in question, as a whole, I do not attach
much importance; for, first, our English microscopes are
generally of too tall a dwi/d to admit of being at all commo-
diously used in a vertical position for any length of time;
and, secondly, if they could be commodiously so used, the
stage would be in the way of the hand; while, moreover, the
paper not bemg in the place where 7¢ seems to be, but away
in front of the instrument, I venture to think that this would
seriously interfere with the free use of the pencil in tracing
the image.

It is to a small adjunct of M. Nachet’s prism that I
refer, as holding out a prospect of advantage; I mean the
piece, marked 8, in Dr. Carpenter’s figure. It is well known
that many—perhaps most—microscopists find considerable

SE7

138 MEMORANDA.

difficulty in using the camera lucida as at present constructed,
owing to the constrained position in which the eye must be
held, half the pupil over and half beyond the edge of the
prism. A partial remedy for this difficulty would be found in
discarding the present form of prism, with its two reflecting
surfaces, and using a prism having only one such surface, and
drilling a small hole through it vertically. Through this hole
the paper would be seen, while the image would be visible by
the rays reflected from the inclined surface of the prism.
The objection to this is that the hole would act, as regards
the rays entering the prism, as an opaque rod, and so render
useless the portion of the reflecting surface immediately
behind it. A complete remedy for the difficulty is suggested
by inspection of Dr. Carpenter’s figure. Instead of making
a hole in the prism, let there be attached to the centre of
its inclined surface, by Canada balsam, an oblique segment
of a small glass cylinder,* so that its base should be pa-
rallel to the upper surface of the prism. The effect now,
on looking into the prism, will be precisely that of a
a hole through it, without the drawback attendant upon an
actual hole. The paper will be clearly seen through the
prism and the cylinder, and the image by reflection from the
inclined surface of the prism, the whole of which surface will
now be available, with the exception of the spot where the
cylindrical segment is attached, which, however, will be so
small as not to be productive of any injurious effect. In fine,
so far as I at present see, I feel warranted in expressing a
belief that by the adoption of the arrangement now suggested,
the difficulty hitherto attendant on the use of the camera
lucida would be entirely prevented.

It has often been matter of wonder with me why our
opticians continue to supply, for microscopical purposes, the
prism with ¢wo reflecting surfaces. These are requisite in
other applications of the camera, for the erection of the
image. But in its application to the microscope we do not
want this.t| What we want, if we had a preference in the
matter, is that the inversion caused by the first reflection be

* Dr. Carpenter calls Nachet’s “ piece EB” a prism. I think he must be
wrong. The gwasi hole will be of the form of a direct section of the piece
employed. A square prism would give a square hole, and a cylinder a cir-
cular one.

+ A polished steel dise (Amici’s disc) has sometimes been employed
instead of the more usual Wollaston’s camera. But the latter will always
be preferred by those who draw from the microscope, simply for the reason
that the image thrown on the paper by it corresponds in position with that
viewed through the microscope.—{ Eps. ]

MEMORANDA. 1389

left alone. I should think that a prism with only one re-
flecting surface would be much more easily worked than one
with two. A prism of the latter form, however, is spoiled
by the slightest clipping of the edge; while, in the arrange-
ment I have proposed, the edge does not come into use—and
it might perhaps be found more advantageous in the working

to have the edges truncated.—P. Gray, 7, St. Paul’s Villas,
Camden Town, N.W.

On the Rarer and Unpescripep Species of DIAtoMACcEs.
By T. Brieutwei., F.L.S. Part II.

ERRATA ET CORRIGENDA.

I regret to find the followmg errors have crept mto my
last paper which need correction.

TEXT.

Page 94, line 4, czser¢ reference to plate “ (Pl. VI, fig. 15).”

G4 a5) 8, for “fie. 15,” read “ 18."

» 94, 4, 4 from bottom, txstead of ‘‘Aulacodiscus,” read “Auliscus
sculptus = A. celatus, Bailey.”

» 95, line 1, for “ Aulacodiscus,” read ‘* Eupodiscus.”

» 95, 4, 6, “ dulacodiscus levis.’ I find this form has been named
and distributed by Dr. Arnott as “4 K7¢/oni;” the specific name
of wale must, therefore, be cancelled, and ‘‘ Az¢tonz”’ substi-
tuted.

» 95, line 19, the specific name should be “ coscinodiscus,” instead of
* nyaidicula.”

» 96, line 6, for “ ‘019 to 0:3,” read “:0019 to :0030.”

One general error runs through all the measurements ; they require an
additional ‘0 in front.

DESCRIPTION OF PLATES.

Plate V.

Fig. 2, insert specific name “ trilingulatus.”
» 4, for “pyxidicula,” read “ coscinodiscus.”
5, for “ Aulacodiscus,’ read “ Auliscus.”
» 2

», 6, disert specific name “ coronatus.”
hy Came = » “marginatus.”
9 “ cervinus.”? .
” 5) 2 2» ” eTvLnUs.
», 10, for “ Aulacodiscus,” read “ Eupodiscus.”
Plate VI.

Fig. 11, czsert specific name “ radiata.”

2 i) ae _ » * semiplanus.”

2? 13, ” ”» »” se Kittoni.”

ce :, >
By kDa | 35 33 3 ‘ spinosa.”
» 16 “ s/ylorum.

3 ” 3? »”
» 17, for “ Eupodiscus,” read “ Actinoptychus interpunctatus.”

140

PROCEEDINGS OF SOCIETIES.

Microscopicat Society, January 11th, 1860.
Dr. Lanxester, President, in the chair.

Tur minutes of the preceding meeting were read and
confirmed.

J. A. Tulk, Esq., 5, East Preston-street, Edinburgh ;
J.C. Forsyth, Esq., Stoke-upon-Trent ; and George Kelly,
Esq., 9, Sutherland-gardens, Maida-vale, were balloted for,
and duly elected members of the Society.

The following papers were read :

1. ‘On the Localities of Diatomaceze,’ by Mr. Norman.
(“Trans p. 59.)

2. ‘On the Reproduction of Confervoid Algz,’? by Mr.
Oruce, ( lrans.., p. 71.)

The following letter, addressed to the President, was
read :—

“My pear Srr,—lI send you three slides of the same object.

‘No. 1, mounted in balsam, without any preparation except
washing away the salt water.

“No. 2, the same burned on the cover, and mounted dry.

““No. 3, the same neither boiled nor burned, and mounted

in fluid. It is probable that, im this last, all the objects may,

during the transit, be deposited on one side of the cell, but a
little shaking will perhaps cause them to become again
scattered, as they were when mounted.

“The first time that it came under my notice, it was sent me,
11th September, 1858, by the Rev. R. Taylor, of Bedlington,
from the coast of Northumberland. I afterwards received it
from Mr. Mansfield Browne, of Liverpool, collected on that
coast. Thereafter it was sent me by Mr. Roper, from the
Norfolk coast ; by Mr. G. Norman, of Hull, from near the
mouth of the Humber; and the other day, I received an
immense quantity of it from Mrs. Macdonald, of St. Andrews,
Fifeshire.

“Tn all these cases it is found on very shallow pools among
the sands; it floats on the surface and forms extensive patches.
If sand adheres, it is easily separated by a slight shaking in
the bottle in which it is collected.

PROCEEDINGS OF SOCIETIES, 14]

“Some have supposed it a diatom allied to Biddulphia
Bayleyi. From its filamentous nature, and having long spines
or cilia, it might, if diatomaceous, be approached to Biddul-
phia; but it takes in turpentine and balsam when dried without
being boiled or burned. Now this can only take place on the
supposition either that there are no partitions (or valves at
the joint—in other words, that the tube is continuous), or that
the wall is porous; either of which is contrary to its being a
diatom at all.

“Some of my correspondents suppose it to be the exuvie of
an annelid; but no one can point out either genus or
species.

“An object of such abundance on our coasts (at St. Andrews
I am informed that a pint of it could have been collected in a
few minutes) must surely be well known to the London
microscopists; and therefore I send you the slides in the hope
that, through its members, you will be able to throw some
light on the point.

“T shallsend a supply of the object itself to Mr. J.T. Norman,
the well-known preparer of microscopic objects ; so that any
one requiring slides may have them from him. They are
best seen on the cover, dry, and not burned; but, unless
burned, they are apt to imbibe damp, and the slide becomes
useless in a year or two. I therefore, myself, prefer them
when mounted dry, after being burned.

“Yours truly,

“<G. WaLKER ARNOTT.’’

** Victoria-terrace,
* Dowanhill, near Glasgow.”

Josh. Gratton, Esq., and R. Beck, Esq., were appoimted
auditors of the Treasurer’s account.

February 8th, 1860.
ANNIVERSARY MEETING.
Dr. Lanxester, President, in the chair.

The minutes of the preceding meeting were read and
confirmed.

Reports from the Council and the Library Committee were
read, together with the Auditors’ Report on the Treasurer’s
accounts; there remaining in his hands a balance of
£25 16s. 10d.

Resolved that these Reports be received and adopted.

142 PROCEEDINGS OF SOCIETIES.

R. Lloyd, Esq., 69, Holborn-hill ; and H. W. Elphinstone,
Esq., 45, Cadogan-place, were balloted for, and duly elected
members of the Society.

The President delivered an address on the progress of the
Society, and of microscopical science generally, during the
past year.

Resolved, that the address now read be printed and circu-
lated in the usual manner, with the Reports of the Council,
the Library Committee, and the Auditors.

March \4th, 1860.
GrorGe Jackson, Esq., in the chair.

John Shepperd, Esq., 11, Sussex-place, Regent’s-park; and
Thomas Kettermgham, Esq., 51, Coleshill-street, Chelsea,
were balloted for and duly elected members of the Society.

The following papers were read :—

‘On the Development of the Diatom-valve,’ by Dr.
Wallich. (‘Trans.,’ p. 129.)

‘On Asterolampra, and some other species of Diatomacee,’
by Dr. Greville. (‘ Trans.,’ p. 102.)

‘On the Ameeboid Conditions of Volvox globator, by Dr.
Hicks. (‘Trans.,’ p. 99.)

‘On a New Zoophyte,’ by Dr. Allman. (‘ Trans.,’ p. 125.)

143

ZOOPHYTOLOGY.

SuetTtanp Poryzoa. Collected by Mr. Barxer. (Continued.)
2. L. Barleei, nn. sp. Pl. XXVI, figs. 1, 2.

L. cellulis ovoideis, convexis, superficie granulosd ; orificio orbiculari tnfra
sinuato, peristomate simplici elevato ; ovicellulis decumbentibus adnatis, ad
marginem supra perforatis.

Cells ovoid, convex; surface granular; orifice orbicular with a sinus
below, peristome thin, raised ; ovicells adnate, decumbent, punctured round
the border above.

Hab. Shetland, Barlee ; on shell.
3. L. canthariformis, n. sp. Pl. XX VI, figs. 3, 4.

L. cellulis late ovoideis, superficie granulosd, punctatd, nitida ; orificio
magno, suborbiculari seu irregulari, peristomate producto, sepius infundibuli-
Sormi, tntegro.

Cells broadly ovoid, surface granular, punctate, shining; orifice large,

suborbicular, oblong, or irregular ; peristome much produced, often infundi-
buliform, entire.

Hab. Shetland, Barlee ; on shell.

4, L. umbonata, un. sp. Pi. XX VI, fig. 1.

L. cellulis oblongis, seriatis, lined elevatd sejunctis ; ad latera perforate,
medio umbonatis, et juxta orificium medio aviculurium mandibulo semicirculart
horizontali gerentibus ; oryficio suborbiculari, infra paullulum constricto,
peristomate simplici spinis 4; supra armato ; ovicellulis umbonatis vittamque
parvam utringue ostendentibus.

Cells oblong, serial, parted by a narrow raised line, punctured on the
sides, and sometimes in front, with smaller pores; furnished with a central
umbho, and having a prominent avicularium with a semicircular horizontal
mandible immediately below the orifice; orifice suborbicular, or sometimes
contracted below; peristome simple, with four spines above; ovicell large,
rounded, umbonate, with a small vitta or depressed area placed obliquely on
each side below.

Had. Shetland, Barlee; on stone.

The only species with which this can well be confounded is
L. verrucosa, which possesses a similar -suboral avicularium,
but always wants, I believe, the central umbo on the cell and
on the ovicell, as well as the vittee on each side of the latter,
which are not unlike those on the ovicell of L. figularis, only
smaller. In Z. verrucosa, also, the ovicell is punctured,

VOL. VIII. M

14.4 ZOOPHYTOLOGY.

whilst in L. umbonata its walls are apparently entire. The
umbo on the ovicell, it may be remarked, is merely that be-
longing to the cell in front of which the ovicell rises.

5. L. bella, n. sp. Pl. XXVII, fig. 2.

L. cellulis ovoideis, perforatis ; orificio suborbiculari, infra sinuato, denticu-
lum internum bifidum ostendenti; peristomato, elevato, subinde incrassato,
inermt ; ovicellulis rotundatis perforatis.

Cells ovate, punctured; orifice orbicular, with a spout-like sinus below,
within which is a rather large, bifid denticle; peristome raised, often
thickened ; ovicell subglobose, punctured.

Hab. Shetland, Barlee ; on shell.

This is the species which I doubtfully termed L. Landsbo-
rovii, when the account of Mr. Barlee’s species was read at
the British Association. It is clearly, however, not that
species as now understood, however much the figures here
given may seem to correspond with that of L. Landsborovit,
in Plate LXXXVI, of the ‘ British Museum Catalogue.’ That
figure was taken from the only specimen of L. Lundsborovit
contained in the Johnstonian Collection, and which was the
sole representative of the species I had then seen. Since
then, however, having received numerous and more perfect
specimens, I have been able to determine the characters of
the species more precisely ; and Fig. 1, Plate CII, of the
‘ British Museum Catalogue,’ erroneously referred to L. reti-
culata, may perhaps be taken as representing its typical form.

The differences between L. bella and L. Landsborovii con-
sist—

1. In the absence in the former of the intercellular raised
line, and

2. In the absence of any avicularian organ on the lower
border of the orifice.

From L. reticulata and L. pertusa the differences are too
obvious to require more particular notice.

The other species of Lepralia which occur in Mr. Barlee’s
collection are—

6. L. Pallasiana, Moll.

7. L. bispinosa, Johnston.
8. L. granifera, Johnston.
9. L. ringeus, Busk.

10. L. discoidea, Busk. Pl. XXVII, figs. 4, 5.

The figure of this species, which in some respects closely
approaches an Alysidota, was inadvertently placed on the
stone, before I remembered that it had been already figured
in (‘ Zoophytology’) Pl. XXII, figs. 7, 8, from specimens

ZOOPHYTOLOGY. 145

collected in Madeira by Mr. J. Y. Johnson. As I am unable
to discover any satisfactory specific distinction between the
northern and southern forms, I am induced to consider them
identical.*

Other species belonging to the family Membraniporide,
which occur in Mr. Barlee’s collection, are—

1. Membranipora Rossel, Savign.

2. BS Pouilletit, Savign.

3. 3 spinifera, Alder.

4. Alysidota Alderi, Busk, which appears to be very abundant.

* In the paper read at the meeting of the British Association, this species
was termed Alysidota conferta.

(To be continued.)

ZOOPHYTOLOGY.

DESCRIPTION OF PLATES XXVI & XXVII.

PLATE XXVI.
Fig.

1 and 2.—Lepralia Barleei, p. 143.
3 and 4.—L. canthariformis, p. 143.

PLATE XXVIII.

1.—Lepralia umbonata, p. 143.
2 and 3.—L. bella, p. 144.
4 and 5.—L. discoidea, p. 144.

JOOPHYTOLOGY.

Plan e XXV

C Busk del.

W West imp

wg

A
7

ZOOPHYTOLO

Plate XXVIL

W West imp

CBusk del

ORIGINAL COMMUNICATIONS.

On the Emrrorment of TRanspareNT InJEections in the
Examination of the Minute Structure of the Human
Pancreas. By Wma. Turner, M.B. (Lond.), Senior
Demonstrator of Anatomy, University of Edinburgh.

THE investigation of the relations of the minute gland ducts
to the ultimate gland follicles in the human pancreas presents
considerable difficulties. This is owing, partly, to the great
delicacy and transparency of the structures, and partly, be-
cause from the close manner in which the minute lobules of
the gland are crowded together, it is difficult to obtain a
satisfactory view of a single isolated lobule. Thus, the mode
of connection of the fine excretory duct of the lobule with
the sacculated gland follicles at its extremity cannot clearly
be estimated. Moreover, if it is attempted to separate the
lobules from each other by tearing them asunder with needles,
the relations of the parts become so disturbed, that the ex-
amination does not afford any very decided results. For
these reasons, it has been customary, in describing the minute
structure of this gland, to refer especially to the appearance
which it presents in the smaller and more common Rodents,
such as the Rat or Mouse.

In these animals the pancreas is spread out in a thin
arborescent manner between two layers of peritoneum, so that
the different lobules lie mostly on the same plane. Their in-
vestigation is on this account comparatively easy, even with-
out the aid of any dissection.*

Being engaged some months ago in making a series of pre-
parations of the human pancreas for the sake of illustrating
the structure of this gland to my microscopic class, I
succeeded in forcing an injection through the excretory duct
into the ultimate follicles of the gland. Ihave been enabled
in this manner to obtain, much more satisfactorily than by
any other process, definite views of their relations to each

* See ‘ Todd’s Cyclopedia,’ Article “ Pancreas.”
VOL. VIII. N

148 TURNER, ON TRANSPARENT INJECTIONS.

other. The injecting fluid which I used was of the same
composition as that recommended by Dr. Lionel Beale, and
employed by him with such success in his investigations into
the minute structure of the liver. It is composed of a mix-
ture of glycerme, spirits of wine, and water, in which Prussian
blue, obtained by precipitation, is suspended.

This injection possesses the great advantage of flowing
easily when cold along the ducts, and, from its great trans-
parency, the organ into which it is thrown can be examined
by transmitted light, and by high magnifying powers, so that
the connections and relations of its component structures can
be much more readily traced than in those cases where
Opaque injections are employed. It is hardly possible, how-
ever, to make a complete injection of all the ultimate lobules
throughout the pancreas ; for in many parts they appear to be
so filled with secreting cells, and the fine ducts proceeding
from them are, in a similar manner, so blocked up with
closely packed epithelium, that the injection cannot flow
along them. But this does not throw any obstruction in the
way of an examination of those lobules into which the injec-
tion has passed ; it rather tends to facilitate it, for the outline
of the ultimate follicles, distended by the blue fluid, comes
out more distinctly, by the contrast which it presents to the
paler non-injected portions.

It will be frequently found advantageous to examine those
lobules, the sacculated follicles of which are only partially
filled by the injection; for in them the general and relative
arrangement can be more distinctly seen than in those lobules
which are completely distended, as in the latter case, owing to
the amount of injection in them, a degree of opacity is pro-
duced which renders the outline of many of the follicles some-
what indistinct. Most of the sections which I have ex-
amined have been made with a Valentin’s knife, and the pre-
parations have been soaked for a short time in glycerine,
which facilitates the investigation of the pancreas, as of many
other animal textures, by increasing the transparency.

The large excretory duct of the pancreas extends along the
centre of the gland from head to tail, and is enclosed on all
sides by the large lobules. From it, at frequent intervals,
smaller ducts proceed, which pass into these large lobules,
and in them divide and subdivide into fine branches,
for the ultimate lobules. Of these fine branches some
arise at right angles, others at a more or less acute angle,
and after a very short course they become connected
with the ultimate gland follicles of the lobule to which they
belong. Each duct, as a general rule, preserves the same
calibre from the point at which it commences, to that at

TURNER, ON TRANSPARENT INJECTIONS. 149

which it either gives off a branch, or terminates in an ulti-
mate lobule. In some instances the ducts possess dilatations
on their walls, which may either be confined to one side, or
may exist at corresponding points on both sides. The same
mode of termination of the fine ducts in the ultimate lobules
does not appear to exist in all cases, but admits of shght dif-
ferences. In some instances the duct passes to the base of
the lobule, and then from it, as from a centre, the saccular
dilatations of the ultimate follicles spring. In others the
duct runs for a short distance along the base of the lobule,
giving origin in its course to the follicles, which are connected
to its sides and extremity. In either case the fine membrane
forming the wall of the duct is continuous with the mem-
brane constituting the wall of the follicles, so that the cavities
of the follicles are continuous with that of the duct. The
number of follicles present in an ultimate lobule varies con-
siderably in different specimens. There are also great dif-
ferences in their shape and size. Some are spheroidal, others
laterally elongated, so as to present a more or less oval form ;
others again are more pyriform. When distended by injec-
tion, they all present convex, smooth, and well-defined out-
lines. On account of the general shape of the follicles, and
the mode in which they are grouped together in the lobule,
they resemble in appearance a bunch of grapes, with which
they have frequently been compared.

The epithelial contents of the follicles are of course com-
pletely concealed in the injected portions of the gland; but in
those lobules into which the injection has not passed, the
shape and general arrangement of the secreting epithelium
may be conveniently studied. It frequently happens that, in
examining sections of the gland, isolated follicles may be seen,
lying perhaps closely together, as if they had originally
formed parts of the same lobule, but still separated by slight
intervals from each other, having probably become detached
from their original connections in the act of making the
section. (Pl. X, fig. 3.) In these isolated follicles the secreting
cells may be generally very distinctly seen. They form a
closely packed layer, liming the inner surface of the membrane
forming the wall of the follicle. Their shape is spheroidal,
so that they form a true glandular epithelium.

Professor Kdlliker, in his ‘ Microscopic Anatomy,’ describes
the pancreas as belonging to the compound racemose group of
glands, of which the salivary glands and the mucous glands of
the mouth may be taken as the type. In his description of
the last-named glands, he states that the grape-like appearance
of the ultimate follicles is owing to the fine ducts being
coiled upon themselves, presenting at intervals numerous

150 TURNER, ON NERVE-FIBRES.

simple or compound dilatations or diverticula. He con-
siders the glandular vesicles to be nothing more than these
dilatations. In my examination of the injected pancreas, I
have not succeeded in sufficiently separating from each other
the various follicles making up a lobule, so as to state whether
the view of Professor Kolliker can be applied to the pancreas.
Whether we hold, however, with the more generally accepted
doctrine, that these follicles are saccular dilatations at the
extremity of the duct, or with Professor Kolliker that they
are produced by a coiling of the duct upon itself, the impor-
tant fact still remains, that the membrane forming the wall
of the follicles is connected with that forming the wall of the
duct, and that the cavity of the one is continuous with that of
the other.

In this communication I have avoided the use of the term
acini, as it has been employed by different observers to express
different structures, so that its use is liable to lead to con-
fusion of ideas; some applying the term to express the ulti-
mate lobules of the gland, whilst by others it is used to signify
the ultimate follicles of these lobules.

Furtuer Oxsservations on the Structure of NeRve-FIsREs.
By Wn. Turner, M.B. (Lond.), Senior Demonstrator
of Anatomy, University of Edinburgh.

In the number of this Journal for October, 1859, appeared
a communication by Professor Lister and myself, ‘On the
Structure of Nerve-Fibres.’? In it we directed attention to
the great benefits to be derived from the use of chromic acid
and carmine in the examination of these fibres. We espe-
cially pointed out the different action of these two substances
upon the constituent structures of the fibres, the axial
cylinders alone being coloured by the carmine, whilst the
medullary sheaths assumed under the action of the chromic
acid a peculiar fibroid appearance. Our observations were
made especially upon transverse sections through the fibres,
not only as they exist in an ordinary spinal nerve, such as
the sciatic, but also as they lie in the columnar portions of
the cord. In addition, we described and figured certain
fibres, views of which were obtained by making longitudinal
sections of the columnar portions of the cord. Since this
paper was printed, I have continued my observations on the
subject, and, by a slight modification of our former process

TURNER, ON NERVE-FIBRES. 151

have succeeded in obtaining extremely satisfactory views of
the axial cylinder, and of the proportion which it bears to
the medullary sheath. From the great simplicity and pre-
cision of this process, I am induced to make the following
communication.

Portions of an ordinary spinal nerve, previously hardened
by immersion in chromic acid, were placed for a few hours in
an ammoniacal solution of carmine. After being removed
from this solution, they were washed with water, spread
out on a glass plate, and then treated with spirit, turpentine,
and Canada balsam in the ordinary way. They were then
examined under a good one-fifth imch object-glass in their
entire state, without sections bemg made through them,
either in one direction or another, the fibres lying in their
natural position parallel to each other.

In the various fibres of the bundle, the axial cylinder was
seen to be deeply tinted by the carmine. It could be traced
along the centre of the fibre, occupying its middle third, and
presenting a perfectly clean and sharply defined outline.

In none of my preparations have I been able to see any of
those “ ramifications ”’ of the axial cylinder into the medul-
lary sheath, which have been so elaborately figured and
described by Stilling.

A careful examination of the numerous figures given by
him in the twenty-fourth plate of his great work, and a com-
parison of these figures with my own preparations, convince
me that the structures which he has described under that
name are nothing more than small fibroid particles of the
medullary sheath itself, and quite distinct structurally from
the axial cylinder. If they had been actual prolongations of
the axial cylinder, they would, like it, have received the car-
mine colour, which, so far as I have seen, never takes
place.

I cannot agree, either, with the opinion expressed by Stil-
ling of the connection of the different fibres im a bundle by
means of fine elementary tubules passing between them.
Each fibre in my preparations possessed a distinct and well-
marked unbroken outline, the only imtermediate material
that I have seen being an extremely delicate, wavy con-
nective tissue, which, although lying between the fibres, does
not in any sense form a part of them. Nerve-fibres, examined
in this manner in their entire condition, afford to the ob-
server, in a more satisfactory way than is permitted by any
other process with which I am acquaimted, a means of arriv-
ing at precise conclusions respecting the absolute differences
between the axial cylinder and the medullary sheath. In
them the almost perfectly homogencous axis contrasts strongly

152 BROWN, ON MICROSCOPICAL MANIPULATION.

with the fibroid appearance of the sheath. This is very
strikingly brought out by the difference of tint, in the pro-
duction of which it must be remembered the carmine has to
soak through the medullary sheath, before it can possibly
reach the axial cylinder. The former is thus placed in a
position most favorable for being tinted by the colouring
material, did it possess any attraction for it. This is not,
however, the case. The latter alone receives the tint. By
this process the continuity of the axial cylinder along a
lengthened portion of nerve-fibre, as long in fact as can con-
veniently be placed upon the glass slide, may satisfactorily
be traced. As one looks at a preparation of this kind, the
comparison between the nerve-fibres in a bundle, each axial
cylinder of which is invested by its own medullary sheath,
and the various strands of an electric cable, each wire of
which is surrounded by its independent insulating invest-
ment, almost involuntarily suggests itself.

rel

Upon Microscoric Maniputation. By Henry Horr
Brown. M.R.C.S.L.

In preparing and mounting objects for the microscope, so

) on i

co

J “A
MN IL ith i

(4)

a
i”

usuch of successful manipulation depends upon system and
order in the detail of operations, that I have ventured to
record some few appliances I have from time to time invented,
with a view of obtaining more uniformly successful results
in this branch of science.

The ‘‘ mounting board” that I use is of 3-inch pine, 21
inches long by 7 inches broad, made according to the
accompanying plan (which is on a scale of + inch to ‘the foot).
The central space (1) is for holding the necessary tools for

Sinaia

f

Sdn A’ MMMM

BROWN, ON MICROSCOPICAL MANIPULATION. 153

preparing and mounting objects; these are kept in their
place by a raised half-inch bead. The circle (at 2) are per-
forations to half the thickness of the wood, for the reception
of pill-boxes, which contain various sizes of cylinder glass,
glass cells, &c., the contents of each box being specified on
the outside. At 3 will be seen three separate pieces of
coloured paper, pasted upon the board, with the length and
breadth of a slide (8x 1) traced upon them, as also a circle of
half and three-quarter inch, for fixing down the cylinder glass
upon the slide after the application of heat. I place it upon
the colour that will best show the object, and holding the
slide true to the square lines, the thin glass can be applied
exactly central by using the circle, as a guide. At 4 are
two compresses made of “spring brass,” (a description of
thin brass, varying in thickness, to be procured from printers,
who use it to separate type). These are for mounting either
in balsam or fluid, and both correct centering and permanent
compression may be kept up ad libitum. Another species of
self-acting compress, and one that I have found most useful,
is made of the same description of brass, and figured below
in the diagram. This is slid on to the end of the glass,

generally with a thin piece of kid to protect the slide, and
by raising the hooked portion it may be dropped upon the
thin glass, the amount of pressure dependent upon the
thickness of the brass.

The microscopic cell-plate is a circular plate of brass one

twelfth of an inch thick, perforated to the diameter of the

154 BROWN, ON MICROSCOPICAL MANIPULATION.

cell, and counter-sunk to the diameter and thickness of the
cylinder glass.

In using this plate I apply sufficient indirect heat to it, and
rub over each of the counter-sunk portions some sealing wax
or shellac; immediately pressing down into each, upon the
softened wax, the thin glass circles. When cold, the centres of
each may be easily removed by perforation with a rat-tailed
file, and trimmed round with a finer (watchmaker’s) file to

the exact diameter of the perforation, the counter-sinking
giving the exact centering. The plate may again be heated
and the cells slid off into
ether, in order to remove
the wax and cleanse them.
This plate is made with
tolerable rapidity and ac-
curacy on a lathe with an
eccentric chuck. I have
also drawn a description of
forceps that I find very
useful in preparing micro-
scopic objects, where it is
of importance to have
gentle pressure, easy of ap-
plication, with, at the same
time, a facility for occa-
sional inspection, as, for
instance, in preparing the
proboscis of a fly for
mounting, and in cases
requiring the lke treat-
ment. These are almost
identical with the forceps
used in artificial fly-dres-
sing, but having cemented
to their extremities two
slips of thin glass, may be
brought at any time under
the field of the microscope.
I have obtained the same
result from an American
athe: peg, fitted with wile in the same way.

BROWN, ON MICROSCOPICAL MANIPULATION. 155

The microscopic stand and mounting apparatus has for its
object the direct and indirect application of heat; facilities
for mounting objects, and also of carrying lenses for dissection
a represents the stand or pediment, f being the receptacle
for the screwed end of the upright (4) and # a sunk portion
of brass, in which works the point (k) of the shank of e.
Upon the upright (0) is first slid the apparatus for indirect

=

ad

heat (c), and fixed at a convenient height by the milled screw
(z). The shank (4) of (e) the “turn-table” is then passed
through the perforation of ¢ at g and its point resting in
h of the pediment ; a rotatory motion may then be given it,

156 NACHET, ON THE CAMERA LUCIDA.

for the purpose either of making varnish cells, or of mounting
preparations in fluid, that have been already fixed by hand.
A circular ring of brass, of sufficient diameter to hold a
watchmaker’s or other lens, is also fitted to the under surface
of c, which may be raised or lowered by the milled head, as
required. Over this upon the upright (d) slides the apparatus
for direct heat (d@), having two catches to fall on the point (/)
of c and retain it in either direction; e is the turn-table
before alluded to, having the half and three-quarter circles
marked upon it, and also two stops (m n), in order that in case
of the removal of the slide before the mounting is complete,
it may be replaced without causing eccentricity.

On the Camera Lucipa. By M. Nacuet, Jun.

In the last number of this journal, Mr. Gray has published
some suggestions on the subject of the Camera lucida, which
lead me to suppose that the various descriptions hitherto
given of our camera, to be employed with the microscope in
the vertical position, have not been well understood by those
who have not seen the instrument. It will not therefore be
useless to offer some considerations, in order to show the
reasons which have induced us to adopt the arrangement in
question. All the forms of camera employed with the
microscope in the vertical* or inclined position may be
arranged in two classes; the first containing those forms in
which the camera gives the image of the object directly, and
that of the pencil by reflexion ; and the second, those, on the
other hand, in which the image of the object is given by
reflexion, and the pencil yiewed directly. The best instance
of a camera belonging to the former category is that of
Amici, formed of a perforated steel mirror, and of a
prism ;+ the object being viewed through the opening, a,
of the mirror, and the pencil reflected by the prism being
seen on the annular surface, c, 6. The inconveniences of

* I may here remark that the vertical camera in itself (as a whole) is not,
as Mr. Gray thinks, to be despised. Micrographers, who work in earnest,
often having to draw objects almost always immersed in fluid, and not
having to delay in order to remove a portion, as is done when objects are
prepared for preservation.

+ The arrangement of this camera has been altered by Chevalier, to
adapt it to the horizontal microscope.

NACHET, ON THE CAMERA LUCIDA, 157

this form of instrument
arise from the nature
itself of the mirror, its

easy destruction, and
the loss of light.

Another instrument
of the same class, and
which affords very
beautiful effects, is the
camera of Doyére,
which is formed of a
very small prism placed
above the ocular, and
of the reflecting prism of Amici’s camera. Its inconveniences
are a certain “delicacy of construction, and the difficulty
of using it; or as observed by Mr. Gray, it is rather difficult
to adjust the eye to the angle of a prism.

Nobert conceived the idea of replacing Amici’s mirror by an
inclined slip of glass; but with this it is difficult to equalize
the hght between the field and the paper, and the two sur-
faces of the glass give a double image of the pencil.

We now come to the second class of cameras, or to those
which give the image of the object by reflexion. These,
after mature consideration, we are of opinion should be
wholly abandoned. They have the grave inconvenience of
reversing the image, so that when it is wished to retouch the
drawing by the eye after the first sketch, it is requi-
site to allow for the reversal of the image, without which,
the draughtsman is always liable to place ‘what should be
above below, and the reverse. Errors of this kind are
especially easy to make when the body designed has a
rounded or symmetrical contour,—such as embryonic
cells, &. Wollaston’s prism, which belongs to the present
class, affords, it is true, an image in the same position as that
in the microscope, but most often it does not take in the
whole field ; and besides, in order ‘to use it, the microscope
must be nearly horizontal.

The problem to be solved therefore being, that itis required
to see first the object, and indirectly the pencil, we have re-
solved it in the following manner. For the vertical microscope
we have adopted the form already described in Dr. Carpenter’s
work on the microscope. The objections made to its use
by Mr. Gray arise from his not having employed it. Thus,
with respect to the sensation produced by the appearance of
the hand in the field of vision, there is nothing disagreeable
or annoying in this ; but, on the contrary, the motions of the

VOL. VIII. )

-

158 NACHET, ON THE CAMERA LUCIDA.

pencil acquire a resolution and firmness rarely met with in
the use of this kind of instrument. Some precautions should
be taken in the construction. The angle of the small at-
tached prism, £, should be
equal to the angle a, so that
the surfaces presented to the
eye are well parallel. The
surface B should be slightly
inchned, so that the pencil
may be seen at some dis-
tance from the mstrument,
in order not to come in con-
tact with the stage. The pro-
jection of the image is thus
rendered a little oblique,
but to so very trifling an
extent that the deformity is
almost inappreciable; and besides, if the paper be a little
inclined, this defect is removed.

The arrangement adopted for the inclined microscope is
based on the same principle as the foregomg. A prism
giving two total reflexions
1S placed above the ocular,
so that the rays coming
perpendicularly from the
table are reflected by 3, c,
and then by c, D, so as to
issue by the same surface,
B, C, which is at the same
time a surface of reflexion
and of transmission. An
image is thus afforded of
the object viewed by the
small prism 8, whilst that of the pencil comes from c, vp. It
follows that, by this prism, Ist, the image of the pencil
appears to be transported into the field of view, and that the
object is viewed in its true situation; and 2dly, that the
observer, looking into the ocular, enjoys the advantage of the
comfortable inclination of the instrument, whilst in the other
systems of cameras the inclmation of the microscope is with-
out advantage, because it is necessary to look vertically upon
the table.

TRANSLATIONS.

The Zoosrores of Curooiyrus, Ag.*

Tue first of the plants to which the observations refer is
Chroolepus aureum, Spr. var. tomentosum, Kg. Under the
microscope, the plant is seen to be formed of erect threads,
intermixed with branched threads, each consisting of a single
row of cells. The walls are colourless, but with a glittering
appearance. (PI. IX, fig. 1,s.) The apical cell of the threads
often has a globular or pulvinate appendage, of a highly re-
fractive nature, furnished with transverse wrinkles, and fre-
quently also with a protuberance at the top. (Figs. 1, 2, 3, 5,
6, 7, 8,9, g.) The whole cavity of the cells is filled with
granular matter, mostly of a brownish-red colour ; but it fre-
quently happens that the inner granules only are brownish
red, whilst the outer ones are green. (Figs. 3, 16, 17, 18.)
The reddish-brown granules seem to be oil-drops. Iodine
seems to turn them to a dirty blue. From the effect of dif-
ferent reagents, the author considers the cell-wall to be
formed of an amylaceous cellulose ; the wrinkled apex, on
the other hand, of some different substance, probably gela-
tine. A great number of the threads terminate with a
globular, much-thickened cell, which subsequently becomes
the mother-cell of the zoospores. (Fig. 3, m.) This mother-
cell is rarely found in the middle of the threads. (Fig. 4, m.)
Occasionally, but still more rarely, the cell immediately
under the mother-cell elongates itself sideways and upwards
into a thread. (Fig. 14.) The mother-cell of the zoospores,
when it forms the terminal cell of the thread, bears a conical
mass of gelatine, often of considerable size (figs. 5, 7, 9, g,),
which, however, is seldom on the crown of the cell, but usu-
ally at its side. (Figs. 3,5, 7,9.) In those mother-cells in

* Condensed from the German of Dr. Caspary, in the ‘Resensburg,
Flora,’ for September 28, 1858, by F. Currey, Esq., M.A., F.R.S., F.L.S.

160 CASPARY, ON THE ZUOSPORES OF CHROOLEPUS.

which the zoospores are about to escape, a division of the
contents into small oval cells is clearly perceptible, (fig. 5),
and at the side, or near the top, the wall is extended into a
short papilla. (Figs. 5, 7, p.) The contents emerge in the
form of a well-defined vesicle, with the zoospores, penetrating
through the ruptured papilla (figs. 6, k, 8, *) ; sometimes,
however, no vesicle is formed. A few moments after emerg-
ing, the vesicle bursts, doubtless by absorption of water, and
the zoospores swim about in every direction. The remnants
of the vesicle are of a gelatinous nature. The escape of the
zoospores was observed from nine in the morning till four in
the afternoon, and seems to depend, not upon the influence
of light, but solely upon the effect of moistening with water.
The zoospores are very small, 0:0035 to 0:0033 mm. They
are filled with reddish-brown granular matter, the apex alone
being free and hyaline; there are two cilia, about three or
four times as long as the spore. The apex, with the cilia,
is directed forwards. They rotate perpetually whilst swim-
ming ; their motion being so rapid as to prevent a clear view
of them, except when stopped by some obstacle, or when
their motion is becoming retarded. When killed by con-
centrated solution of iodine, or iodide of potash, the zoo-
spores appear brown, with the exception of the apex, which is
hyaline as before; the cilia are very little browned, but be-
come more distinct. The cell is surrounded by a clear,
highly-refractive border (figs. 10, 11, 12), looking like gela-
tine, but which may be only an optical appearance. Treated
with iodine and diluted sulphuric acid, the whole zoospore,
apex and cilia, become deep brown. (Fig. 13.) After con-
tinuing in motion for about an hour, the zoospores become
sluggish, sink, become globular (fig. 15), elongate them-
selves (fig. 16, a, 6, c), and shortly a division of the cell
takes place by a transverse septum. (Figs. 17, a, 4, c, d.)
Some reddish-brown granules usually remain behind in the
empty mother-cell, and in the remnant of the vesicle. (Fig.
9, k.) Oftentimes some zoospores cannot emerge from the
mother-cell, and then they sometimes geminate in it.

Chroolepus umbrinum, Kg.

Chrovlepus umbrinum, Kg. ‘ Phycol. gener.,’ 1842, p. 288. ‘ Raben-
horst Deutsch. Kryptog.,’ 1845, ii, 2, 87.

_ This plant is common about Bonn, on the bark of trees,
in the form of a reddish-brown, scentless, thin stratum, prin-
cipally on the northern side of the tree. The zoospores were

CASPARY, ON THE ZOOSPORES OF CiITROOLEPUS, 161

observed in the middle of July, 1856, and in May, 1857 ; but
after the dry and hot spring of 1858, were sought for in vain.
They have never been found in the autumn, or late in the
summer. In order to find them, it is a good plan to leave a
piece of the bark covered with the plant in a damp vasculum
for a night. Chroolepus umbrinum usually forms solitary’
globular cells, frequently, however, exhibiting two or three
together (figs. 18 and 19), and rarely as many as from four
to seven. The gobular or sub-globular cells are 00071 to
0:0098 mm. in diameter. The membrane is thick, and con-
sists of cellulose; it is not coloured, however, by iodine, but
it becomes of a beautiful blue under iodine and sulphuric
acid. (Fig. 20.) The contents consist of small granules,
coloured reddish brown by the colouring matter adherent to
them ; they are turned to a dirty blue by iodine, and con-
sist of starch and of large, reddish-brown, highly refractive
oil-drops. Strange to say, the oil-drops are coloured a deep
dirty blue by iodine. The zoospores are not so numerous
as in C. aureum. The mother-cells of the zoospores are some-
what larger than the vegetative cells, but not otherwise dis-
tinguishable. The spores are larger than in C. aureum (figs.
21 and 22), and 0-0042 to 0:0043 in length. They are oval
on one side (fig. 21), but quite flat on the other (fig. 22), and
rotate perpetually in swimming. They have a clear border
(figs. 21 and 22, s) (? substantial or an optical appearance),
which remains after treatment with iodine, or with iodine
and diluted sulphuric acid. The apex of the zoospores is
colourless, the expanded hinder portion being filled with red-
dish-brown granular matter. They have two cilia at the apex,
which are two or three times as long as the cell. When treated
with iodine, the apex remains colourless and hyaline; the upper
part, however, becomes of a dirty bluecolour. (Figs. 25 and
26.) If diluted sulphuric acid is employed after iodine, the
whole cell, including the apex and cilia, becomes of a deep
brown colour, but a tinge of dirty blue is still visible in the
middle of the cell. (Fig. 27.)

The zoospores, therefore, of Chroolepus umbrinum, are acted
upon by reagents very similarly to those of C. aureum, the
difference being that the reddish-brown granular contents of
C. umbrinum are somewhat firmer, whilst the contents of
C. aureum consist of a substance not coloured blue by iodine.
It is particularly worthy of notice, that the hyaline apex of
the zoospores of both plants is not rendered brown, but re-
mains colourless under iodine, proving, it would seem, the
absence of nitrogenous matter in the covering of the zoospores
of Chroolepus, or at least in the apical portion of it. The
author was unable to separate the covering from the cell-:

162 CASPARY, ON THE ZOOSPORES OF CHROOLEPUS.

contents ; and therefore in Chroolepus aureum, where the cell-
contents are rendered brown by iodine, he cannot say whether
the whole of the covering, or only its apex, is unaffected by
the iodine. But inasmuch as, in C. umbrinum, the zoospore,
even after treatment with a strong solution of iodine and
iodide of potassium, exhibits, on account of its amylaceous
nature, only a dirty blue colour, and not a brown, it seems
probable that the whole remaining portion of the cell-cover-
ing is of the same nature as its apex, that it is not coloured
brown, and consequently is not nitrogenous. From its
behaviour under iodine and sulphuric acid, the cell-covering
probably does not consist of cellulose, although in the present
state of microscopical chemistry it is not easy to say accurately
of what it does consist. The observation, however, is an
interesting addition to our knowledge of the nature of the
covering of zoospores, which covering has hitherto been sup-
posed to be always coloured brown by iodine, and to be there-
fore nitrogenous. At all events the cell-covering, or at least
the apical portion, cannot in Chroolepus be looked upon as a
primordial utricle. It would seem that the subsequently
formed cellulose membrane of the cells of Chroolepus is pre-
sent in the zoospores at the period of swarming, but that in
this condition the young membrane does not exhibit the con-
sistency or the reactions which are afterwards visible in it.
The author then proceeds to observe, that the existence of so
peculiar a membrane is less surprising, as there are several
other algee which exhibit unusual chemical peculiarities in
their cell-coverings ; and after noticing several instances of
such alge, he concludes that there are modifications of
cellulose dependent upon the age and the species of the plant,
which do not exhibit the usual reactions ; and that it is there-
fore fair to-assume that the membrane of the zoospores of
Chroolepus, or at least the colourless apex of the membrane,
consists, at the period of swarming, of a modification of
cellulose not exhibiting the usual reactions, whilst the zoo-
spores of other plants are only clothed with a nitrogenous
primordial utricle.

The young membrane of the zoospores of C. umbrinum is
very delicate, and disappears soon after the death of the
zoospores, of which a few only lived to vegetate. The brown
granular contents of those which died escaped in all directions
(exhibiting active molecular motion) very shortly after the
cessation of the motion of the zoospores, showing that the
cell-wall did not burst, but dissolved. (See fig. 24.) Fig. 23
shows the remnants of a zoospore, consisting of a heap of
granules surrounded by a gelatinous mass (s) which belonged
to the cell-contents, not to the membrane. Iodine did not

WELCKER, ON SARCINA. 163

colour these granules blue, but it rendered the cilia visible,
the latter appearing to be able to resist dissolution for a longer
period than the cell-membrane. The granules had all a
border (s) around their nucleus (k). (See fig. 23, 6.) The
author did not see the zoospores attach themselves to any
foreign body; they simply sank. Some of the zoospores of
C. aureum, which were kept moist under glass, increased by
cell-division.

Agardh rightly placed Chroolepus amongst the algze; he
considered it to belong tothe Confervoidez. Kiitzing, in his
‘ Phycologia generalis,’ placed it with the Chantransiz, and in
his ‘Species Algarum,’ with the Confervee. The author
considers the latter its proper place, in juxtaposition with
Cladophora.

On Sarcina, and especially on its occurrence in the Unie of
Man. By Dr. Hermann WELcKER.

Tue following is an abstract of Dr. Welcker’s communi-
cation, which has appeared in Henle and Pfeuffer’s ‘ Zeitsch. f.
Rat. Med.,’ 3d ser., vol. v, p. 199 (1859).

The most usual situation in which the sarcina occurs is,
as is well known, in matters ejected by vomiting from
the stomach, and it appears to be a common concomitant of
chronic vomiting. It appears, however, to be occasionally
present in the stomach, in cases where no symptoms of
gastric derangement had existed.

Its occurrence in the urine has been frequently noticed ;
thrice by Heller, once by Dr. Mackay, twice by Dr. Johnson,
and twice also by Dr. Beale.

Notwithstanding the hesitation with which Zenker admits
the probability of the occurrence of sarcina in the urinary
secretion, no doubt can be entertained, that in the cases about
to be detailed, the Sarcina originated in the urinary organs
themselves, and did not gain admission through any fistulous
passage, nor had become accidentally mixed with the urine.
But whether the sarcina were confined solely to the bladder,
or occurred also in the pelves of the kidneys and tuduli
urinifert, roust still be left undetermined,

164 WELCKER, ON SARCINA.

With respect to other situations m which the occurrence
of sarcina has been noticed, may be mentioned, in the feces
and intestinal canal, by Bennett and Hasse; in cholera-stools,
by Wedl and Mensonides; in the contents of portion of
gangrenous strangulated intestine, by Demme; in the bron-
chia, by Virchow and Friedreich; in the substance of the
lungs, by Zenker, Virchow, and Demme; in the fluid of the
cerebral ventricles, but under doubtful circumstances, by
Jenner.* In animals, it has been found by Virchow in the
stomach of the rabbit, and in that of the dog by Frerichs;
whilst, more lately, Eberth has found it in the intestine of
the ape, and in the czecum of the common fowl, &c. .

No specific distinction has hitherto been drawn between
the kinds of Sarcina derived from these various localities,
although diversities in the size and colour of the corpuscles
have been incidentally noticed.

The case in which I observed the occurrence of Sarcina in
the urine, was that of a medical man, forty-seven years old,
who had been ailing for some years, and was consequently
somewhat emaciated, and had lost much strength. He
suffered much from nervous excitability and depression of
spirits, and entertained a vague suspicion that he was
labouring under some renal affection, even before the dis-
covery of the sarcina in his urme. He never vomited, and
there was no evidence of the existence of Sarcina in the
stomach.

I first examined the urine on the Ist, 2d, and 5th July,
1857. It was strongly acid, and very shortly after its emis-
sion presented, when contained in a test-tube three fourths
of an inch in diameter, a light-whitish cloudiness. ‘This,
when the fluid was closely examined by the naked eye, by
transmitted light, was seen to be caused by the presence of
very minute grayish-white corpuscles, which microscopic
examination proved to be nothing but sarcina. At the end
of about an hour these corpuscles had subsided, and formed
a grayish-white, light sediment, occupying about one tenth
of the length of the tube.

In the urine just passed into a perfectly clean glass, the
microscope detected—

1. Very numerous specimens of sarcina.

2. Crystals of oxalate of lime.

* To these instances may be added two or three in which the occurrence
of Sarcina was noticed by ourselves in the contents of the stomach—
especially in one remarkable case of rupture of the diaphragm, in which the
stomach was forced into the left side of the thorax, and became distended
with an enormous quantity of brown grumous fluid, consisting almost
entirely of Sarcina ventriculi. [G. B.]

WELCKER, ON SARCINA. 165

3. A few pus- or mucus-corpuscles, and some traces of
epithelium (but no fibrinous casts, and the urine was never
albuminous).

As nearly as could be estimated, the Sarcina constituted
95, the crystals 4, and the other corpuscles 1 per cent. of
the morphological elements in the urime .

The Sarcina presented the following diversities of form in
the corpuscles :

1. Isolated cells, 0:°0010 to 0:0018 mm. in diameter, which,
although, on the whole, of a rounded form, in larger specimens
were more angular and cubical. That these were reaily
sarcina-cells, elements of the cubes to be presently described,
is shown, in the first place, by their size, which much exceeded
that of colourless blood-corpuscles or pus-cells. On the
application of acetic acid also, no nucleus was rendered
apparent in the sarcina-cells, as in the bodies just men-
tioned ; whilst iodine produced in them the same yellowish-
brown colour as in the entire sarcina-cubes.

2. Cubical masses, exhibiting on each face four cells, and
which consisted therefore of eight cells. The sides of the
smaller of these cubes measured 0°0020 mm., and of the
largest 0:0027 mm.

3. Cubes with four cells on each side, that is to say, con-
stituted of sixteen cells in each face, and consequently
forming packets of sixty-four cells. Each side of these cubes
was 0:0042. mm. to 0:0052 mm. long. Larger cubes than these
were never observed in the urme. On the other hand, in
some specimens of the sixty-four celled packets, it might
very readily be seen that these bodies were to some extent not
mathematical cubes. In these instances the face presented
to the observer was for the most part an oblong, 0:0052 mm.
in length, and 0:0050 mm. in breadth. The illuminated
cross, constituted of two lines bisecting each other in the
middle, and by which the sixteen cells are divided into four
groups, exhibited in these cases a longer and shorter limb;
a condition which probably indicates the first line of fissure
of the entire bundle. Lastly, the urine presented :

4. Columnar sarcina-masses, 0°0050 mm. long, 0°0025 mm.
broad, and exhibiting on the four larger faces eight, and
in the two smaller four, and consequently, in the whole,
sixteen cells. These masses, in all probability, arise from
the division of the sixty-four cell bundles.

By far the majority of the sarcina-masses in the urine
belonged to the second and third forms, that is to say, were
cubes composed of eight or of sixty-four cells.

It at once occurred to me that the sarcina-masses ejected
from the stomach are of far larger dimensions than those just

166 WELCKER, ON SARCINA.

described. With respect to this, I am able to avail myself
of six observations of Sarcina ventriculi, as affording materials
for measurement; and, in the following table, I give their
mean dimensions in these instances, with those of the
ss si in the case I am describing, placed opposite each
other :

URINE. STOMACH.

Primitive cell . ; - | 0°0012 mm. | 0°0025 mm.
Cube of 8 cells . . | 0°0023 mm. 0:0050 mm.
AMOR OAT UE. Bue 00048 mm. | 0:0100 mm.
Nace ail eee ree. none. / 00200 mm.
| - HOkA0SG Dent = . none. | 0:0400 mm.

With respect to the measurements given by various
authors of the Sarcina met with in the stomach and intes-
tinal canal, they appear, when allowance is made for the
different modes in which they have been made, to show
sufficiently well that the objects described by these authors
are, as regards their dimensions, identical with those placed in
the second column of the above table, but not with the
urine sarcina.

It appears to me, therefore, that we have to do with two
distinct species. The sarcina of the urine is, in all respects,
smaller than that ejected from the stomach. Cubes contain-
ing 512 cells do not appear to occur in the urine; and
whilst the stomach-sarcina consists chiefly of bundles con-
stituted of 512 and 4,096 cells, in that form which occurs in
the urine, the bundles, when the number of cells reaches
sixty-four, break up into their elements, which separate and
represent new, isolated individuals.

It would be interesting to inquire, whether in the sarcina
previously observed in the urine, the dimensions were as
small as in the preceding instance; but to determine this
no materials exist.

That the early disintegration of the Sarcina urine, as
well as the smallness of its cells, are merely accidental and
dependent upon the condition under which it exists, and
that, if introduced into the stomach, it would reach the
same size, appears to me hardly probable.

The determination of the question, whether the sarcina of
the urine be a distinct species, or, at any rate, a variety
of the common sarcina, is not without interest ; and I much
regret that no opportunity, owing to the unexpected de-

WELCKER, ON SARCINA. 167

parture of the patient, was afforded for further experiments
than those I shall now mention, for its determination.

The author then proceeds to detail some experiments, in
which he injected some of the urine, containing sarcina, into
the bladder of a rabbit and of a dog, without any result.
Its introduction also into the stomach of the former animal,
with its food, was also unattended with any result; no
trace of the sarcina being found in either case, either in the
urine during life, or in the organs after death.

Some observations are then made on the mode of develop-
ment and systematic position of the Sarcina; but, as these
do not appear to contain anything of importance, we pass
them over, and conclude with the following list of queries,
which are suggested by Dr. Welcker, as demanding atten-
tion.

1. Does the Sarcina urine always exhibit the small dimen-
sions above indicated, of the isolated cells, as well as of the
entire bundle ?

2. Hasthe Sarcina found in other situations also, as in the
lungs, for instance, the same or very similar characters ?

3. Is the transplantation of Sarcina urine into the
stomach always without result? Or, does it, under these
circumstances, retain its peculiar characters, or assume those
of Sarcina ventriculi ?

4. What is the result of the imtroduction of Sarcina
ventriculi into the urimary bladder ?

5. Is Sarcina urine never, or at any rate so rarely accom-
panied by Sarcina ventriculi, that even in this respect the
two forms appear to be independent of each other?

6. Is the urmary bladder the only habitat of Sarcina
urine ; or, is it also to be found in the pelvis of the kidney
and the tubuli uriniferi ?

7. Is the presence of sarcina in the urime accom-
panied with any special morbid condition of the uro-genital
system ?

8. In case the last question should be answered in the
affirmative, in what way does the infection with Sarcina
urine take place ?

9. What means have we, and especially by injection, for
the destruction of the Sarcina ?

168

On the Marure Conpition of TRICHINA sPIRALIS. By
Dr. Ruvotew LevcKarr.

Some months since I communicated to my friend, Professor
Van Beneden, at Louvain, the results of a helminthological
experiment, which appeared to establish the connexion of
Trichina with Trichocephalus, already supposed to exist by
Meissner, Kiichenmeister, and others. In this experiment,
I fed a young pig with a quantity of trichinised flesh, for
which I had been indebted to the kindness of Professor
Nasse of Marburg; and on dissection, after the lapse of four
weeks, I discovered in the large intestine a very considerable
number of Trichocephalus dispar, probably thirty or forty
specimens, some of which were in a state of perfect sexual
maturity, and some nearly in that condition.

Professor Van Beneden communicated the result of this
experiment to M. Milne-Edwards, who regarded it of such
importance that he considered it worthy of a brief notice
before the Academy of Sciences in Paris.

Shortly afterwards a letter from Professor Virchow was
read in the same place, in which it was stated that in the
intestine of a dog fed with flesh containnmg Trichina, at the
end of four days a vast number of minute free vermiculi were
found, which were manifestly sexually mature Trichine, or
which, at any rate, were in a condition approaching matu-
rity. With respect to the ultimate destiny of these vermi-
culi the observer remained in doubt, not regarding it as
altogether impossible that they might become Trichocephali ;
he was, however, more inclined to assume that they had some
relation to Strongylus.

I must confess that on reading this letter I suspected some
error on Virchow’s part, chiefly because, according to all ex-
isting experience, it appeared incredible that a previously
asexual worm (for such is the Trichina, although already pre-
senting the rudiments of a sexual organ) should, so early as
on the fourth day after importation, “be found to contain
fully developed ova.”

But I must hasten to retract this supposition of error, as
totally unfounded.

According to my present researches, there can be no doubt
that Virchow is perfectly right. T'richina spiralis, in the
intestine of the po, assumes, in a very short time, the con-
dition of sexual maturity, but independently of a previous

- transformation into any already known form of thread worm.

A short time since I obtained from Professor Welcker, of

LEUCKART, ON TRICHINA SPIRALIS. 169

Halle, a large quantity of human flesh, containing a great
abundance of Trichina. With this I fed a number of puppies
and two young pigs; and examined one of the former on the
fourth, and one on the seventh day afterwards. In both I
found innumerable free Trichine, which, however, in the first
case were intermixed with others still in the encysted con-
dition. The free worms were full grown. In the second dog
some of them were 3 mm. (about 4 inch) long, and, at any
rate in that animal, were all sexually mature.

As I do not intend, on this occasion, to give a complete
account of my observations, it will be sufficient to say a few
words respecting these mature Trichine.

The females were by far the more numerous, being in pro-
proportion to the males, perhaps, as forty to one. They were
found between the villi of the intestine, as well as in the
intestinal mucus and in the feces ; in the colon, cecum, and
second half of the small intestine, but especially.in the former
situations, in such numbers, that in a portion of mucus, or of
mucous membrane, about the dimensions of a lentil bean
there would be found, on the average, from six to ten spe-
cimens.

Of the organs in the female body, the uterus is by far the
most considerable. It is a simple, very thick canal, occupy-
ing in the posterior half of the worm nearly the entire cavity
of the body, and opening with a constricted neck at the
posterior border of the anterior fourth. Its contents consist
of ova of comparatively very large size, and exhibiting all
stages of segmentation and embryonic development. The
female Trichine are viviparous nematodes, whose embryos are
of disproportionate length. The number of ova and embryos
in the largest specimens (the smaller, for the most part, contain
none) may be estimated at about a hundred or more.

With the exception of this uterus and their size, the
mature Trichine differ in no respect from the well-known
T. spiralis.

The male Zrichine are smaller than the female, rarely
measuring more than 2 mm. (about 0:1 inch) in length.

This deficiency in length is referrible more particularly to
the posterior half of the body, beginning at the commence-
ment of the chyle-stomach, and constituting the portion in
which are included, besides the stomach, the simple tubular
testes, containing innumerable very minute spermatic cor-
puscles (which might also be perceived in the genital tube of
the female). The opening of the testis is placed at the
hinder extremity of the body, immediately in front of the
anus. This extremity of the worm is not curved, but, on the
other hand, is characterised by the presence of two short.

170 LEUCKART, ON TRICHINA SPIRALIS.

conical eminences placed on either side of the genital orifice,
and much resembling the well-known conformation of the

egenus Protecosacter. Spicule are everywhere present, but of
extreme delicacy.

The Trichine above described are, as is obvious at a glance
(and as is shown more especially by the presence of the
embryos in the female), full-grown. Moreover, there can be
no doubt that they do not undergo any further metamorphosis
(into Trichocephalus or Strongylus, &c.)

Notwithstanding the vast numbers in which they occurred
in the animals examined, and in which they must exist in
other cases, these nematodes have hitherto escaped the notice
of helminthologists. The generic appellation of Trichina
might be retained for them, although the specific term
“ spiralis” is hardly applicable to the fully developed
worm.

In what way man becomes infected with the embryos of
this Trichina I shall not here describe in detail. That he
derives his Trichina, like the Echinococcus, from the Dog,
can scarcely be doubted. I will in addition merely remark
that I have, perhaps superfluously, instituted an experiment
in elucidation of this point, having administered to a young
pig the intestine of the last-mentioned dog, with its contents.
We know that the Zrichina in the encysted condition also
occw's in the Pig; the experiment consequently may be ex-
pected to prove successful.

Under these circumstances I shall probably have an oppor-
tunity of communicating further observations on the
subject.

A third dog, which was examined twelve days after feeding,
afforded only a few Trichine, which differed in no respect from
the preceding. They were found exclusively in the colon—a
circumstance inducing the belief that the mature Trichina,
notwithstanding the abundance in which it is at first found,
nevertheless remains only a short time in its nest. And it
may also be stated, that in previous experiments, in animals
examined some weeks after feeding, no vestige of Trichina
was ever met with.

The pigs referred to are still alive, and have in the mean-
while served for experiments of another kind. Their feces,
on the sixth day after the feeding, contained no Trichina.

[The further results of Professor Leuckart’s observations on
Trichina are communicated in the ‘ Géttinger Nachrichten’
for April 30th, and may be thus briefly summed up. |

That the Trichina spiralis, as met with in the muscular
tissue, represents the immature condition of a nematoid

KOLLIKER, ON VEGETABLE PARASITES. 171

worm, which becomes fully developed in the intestinal canal
of many warm-blooded animals, both mammalia and _ birds ;
amongst which are enumerated the dog, cat, pig, sheep,
mouse, man, and the common fowl. The 7vichina attains full
sexual maturity in about two days after its introduction into
the intestine. It is viviparous, and the minute filaria-form
embryos which are produced in about six days more, imme-
diately commence their migration by penetrating the walls
of the intestine, in order to reach the striped muscular tissue.
The greater part of the embryos remain in the muscles
immediately surrounding the visceral cavities. They make
their way through the intermuscular connective tissue, but
ultimately penetrate into the interior of the muscular fasciculi,
where they reach, in about fourteen days, the size and assume
the structure of the well-known Tvichina spiralis. It would
appear also that the immigration of the young Trichine in
great numbers may cause very serious symptoms, either from
peritonitis caused by their passage through the walls of the
intestine, or great debility in consequence of the disintegra-
tion of the muscular tissue.

On the frequent OccuRRENCE of VEGETABLE PaRasiTEs in
the Harp Tissurs of the Lowrr Animats. By Prof. A.
KOLLIKER.

(Abstracted from the ‘Zeitsch. f. Wiss. Zoolog.,’ vol. x, p. 215; 1859.)

In examining the scales of Beryx ornatus, Ag., from the
chalk formation in England, I noticed peculiar tubular
structures, presenting an elegant stelliform figure, of which
I was at first at a loss what to make. ‘Their similarity
in form to pigment-cells led me at first to think they
might be of that nature, but this idea was abandoned when
I found that the structures in question occurred not merely
in the external layers of the scales, but in the interior as
well. At the same time I was unable to entertain any
other supposition, since the structure exhibited no points of
resemblance with any of the known forms of tubular and
cellular structures of bones and scales.

Shortly afterwards, on proceeding to the investigation of
the skeleton of the stony Corals and Sponges, I was again
struck with the occurrence of curious elongated, delicate
systems of canals, the further examination of which soon
opened my eyes, and finally led to the conviction that in all
those cases the appearances were due simply to the presence

172 KOLLIKER, ON VEGETABLE PARASITES.

of vegetable parasites in the interior of the hard tissues under
examination.

I was at once reminded of the observations of Bowerbank,
Carpenter, Rose, and Claparéde, respecting the occurrence
of peculiar tubes in the shells of Lamellibranchs, and of
Neritina, and in fossil fish-scales; and which tubes had
also been regarded by the two last-named authors, as of
parasitic origin. I found also, on comparison with the pre-
parations of shell for which I have been indebted to Dr.
Carpenter, that the canals observable in them also belonged
to the same category.

‘These circumstances, and further investigation, carried
as far as I was able, gradually opened up a wide circle of
facts and appearances, at any rate of such importance as to
induce me not to delay their publication, though still in-
complete.

First and foremost, it is in any case, physiologically, a cir-
cumstance of no little interest, to learn that even such hard and
compact structures as corals, shells, the scales of fish, and horny
skeletons of sponges are bored and frequently pervaded in
an incredible manner by lower forms of plants ; in fact, as I
would at once remark, by fungi. And here the question—
not easily to be answered—arises as to the means by which
these organisms are enabled to remove or displace the car-
bonate of lime and the organic substance of the tissues thus
invaded. But besides this, the correct knowledge of these
phenomena is of importance to zoologists, who would thus be
protected from great errors in the explanation of the struc-
tural conditions of the hard tissues in question. It is well
known that Carpenter, under the term “ tubular structures,”
has designated as a special histological formation in bivalve
shells, those portions which contain tubuli—a notion which
has obtained pretty general acceptance, and which has been
combated by no one (vid. Quekett, ‘ Histol. Catalogue,’ vol. i ;
Leydig, ‘ Lebrb. d. Histol.,’ p. 108 ; Siebold, ‘Comp. Anat.’),
and which I have myself also adopted in my memoir upon
“ Pore-canals and Cell-secretions,” at least as respects cer-
tain genera. At the same time, however, I have always ex-
cepted the horizontally spreading and anastomosing systems
of tubes, with respect to whose true nature I have invariably
reserved any expression of opinion. But it is now clear,
that when the parasitic nature of certain systems of canals
in shells is established, as is actually the case, the occurrence
of a true “ tubular structure” is at once brought into ques-
tion; and the same may be said also with respect to the
allied conditions in other hard tissues. With regard to the
tubuli in the skeleton of the stony corals, seen, so far as I

KOLLIKER, ON VEGETABLE PARASITES. 173

know, only by Quekett, I myself at first regarded these as a
peculiar plasmatic canal-system, and congratulated myself
upon being able to add something to the knowledge of the
organization of this skeleton, until further imvestigation
taught me better.

From Dr. Bowerbank I have received sponges infested
with fungi, with the statement that these sponges exhibited
a special tubular system. As regards Rose and Claparéde,
these authors, although they conjecture the foreign nature
of the tubes in fish-scales and shells of Neritina, were not
in a position to express any definite opinion regarding their
nature and origin. If to this it be added, that systems
of tubuli, whose nature is not so easily explained, are met
with in several other tissues besides those already men-
tioned, as in the chitinous structures of the Articulata,
in the axis of Virgularia, in the hard tissues of the Echino-
dermata, the scales and bones of living Ganoid fishes, it is ob-
vious that a careful comparison and investigation of these con-
ditions is an indispensable and important zoological problem.*

With these preliminary remarks, I will now proceed to
give an account of the special observations I have made.

1. SPonGEs.

During my last stay in England, in the spring of 1859,
I obtaimed, through the kindness of Dr. Bowerbank, a
series of sponges, amongst which were two having tubular
structures in a horny skeleton. The more marked one
of these was described by Dr. Bowerbank as a “ sponge
from Australia, nearly allied to the fossil genus Choanites ;’?
and he added, that “it presented a peculiar form of horny
skeleton, whose fibres are covered with a network of tubules.”
The close investigation of this sponge afforded the following
results.

The skeleton of the sponge itself, to judge from the small
fragment at my disposal, was wholly composed of a network
of the well-known yellowish, horny fibres, as they are
termed, which presented no peculiarity, except that the
fibres were of very various dimensions. Whilst the smaller

* Since the above was written, I have received a work by Weld, “On
the Nature of the Canals which exist in the Shells of several Acephala and
Gasteropoda,” contained in the ‘ Sitz. bericht. d. Wien. Akad.,’ Bd. xxxiii,
p- 451, 1859. Wedl communicated his observations to the Academy on
the 14th October, 1858, and they consequently have precedence of mine;
but as they refer only to two divisions of the lower animals, I still regard
the publication of my researches as not superfluous, and the more so because,
in the explanation of the nature of -the parasites, I am not wholly in
accord with Wedl.

VOL. VIII. > e

174 KOLLIKER, ON VEGETABLE PARASITES.

fibres, besides the fungoid structures, presented no other
elements, in the larger might be observed a certain number of
‘silicious spicule, some of which were simple elongated
needles with a club-shaped, thickened end at one extremity ;
some in the form of a trident, and disposed sometimés
heaped together in the axis of the fibre, sometimes with
their points projecting more or less above its surface.

Now, with respect to the vegetable parasite, this growth is
visible, in my specimen, on all the fibres, without exception,
in the greatest profusion. (Pl. VIII, fig. 1.) It isa unicellular
fungus, whose filaments measure, for the most part, between
0:001'"" and 0:002" ; and, in my dried preparations, all contain
‘air, which renders it very easy to trace them. But even when
the air is expelled by water or hydrochloric acid, they are still
very readily seen; whilst glycerine and balsam render them
“so indistinct that, at any rate, all the ramifications are not
well shown. As regards their disposition and course, in
general two kinds of filaments may be distinguished; a
deeper set, which are longer and straighter, and a super-
ficial, which are much branched. The former, usually of
rather larger size, run in a straight or slightly serpentine
course, sometimes in the axis of the horny fibre, though,
in the thicker fibres, on the outside of the spicule there
assembled, but sometimes, at any rate, at a certain distance
from the surface. They ramify but very sparigly, except
‘that they give off a good many branches, which proceed to
‘the surface of the fibre at a right angle. Occasionally, how-
ever, in preparations well filled with air, I have noticed
tubuli furnished with ramuscules running out to a fine
point, frequently assembled into bundles, and so numerous,
as to give the tubule from which they spring the appear-
ance of the stem of a rose. Widely different was
the habit of the superficial filaments which exist in such
abundance in the outermost layers of the horny fibres, as
to afford, when the surface is brought into focus, the
appearance, as stated by Bowerbank, as if the filaments were
‘surrounded with a network of tubules. When these fila-
ments are examined more closely, it will be seen that they
are prolongations from the inner filaments, and are some-
times richly branched, and sometimes also anastomosing.
The branches are, for the most part, spread out hori-
-zontally ; and it is these, as I thik I have certaimly con-
vinced myself, which, in some cases, are connected together ;
‘a condition which, it is well known, is observed in the
mycelium of various fungi. But, besides these, numerous
very short offsets arise from the superficial filaments, most
of which proceed directly outwards, and appear, in fact,

KOLLIKER, ON VEGETABLE PARASITES. 175

to open on the surface of the horny fibre. At any rate,
there may often be perceived on the fibres, when viewed on
the surface, and in side-views, pretty distinct openings ; and
moreover, especially on the addition of acid, the air always
escapes from the fungus filaments at certain determinate
spots.

My justification, in regarding all the above-described
filaments as belonging to a fungus, lies in the circumstance
that I have succeeded in demonstrating, together with them,
the existence of numerous sporangia. (Figs.2, 3.) The fertile
filaments are, as it seems to me, all, or the majority of them,
short ramuscules of the superficial network, passing inwards,
and supporting at the extremity rounded sporangia, from
0:91’” to 0:015'" in size, and when viewed on the side, of a
hemispherical form. The minute structure of these bodies
could not be ascertained, owing to the appearances being
obscured by the air among the spores. Even when the air
was expelled by means of balsam, little was gained, inasmuch
as the transparency of the whole was then too great to allow
anything to be seen beyond an indistinctly areolar substance.
In a good many sporangia the spores were in a germinating
condition, and not unfrequently presented delicate branch-
ing figures.

A second sponge also given to me by Dr. Bowerbank, and
described by him as “a true sponge with tubuli in the
fibres,” has a horny skeleton without spicules, and numerous
anastomosing fibres pretty nearly all of the same diameter.
The fungus-filaments in this sponge are found by no means
in all the fibres of the skeleton, entire portions occurring
wholly free from them; an important fact, inasmuch as in
this case the adventitious nature of the enclosed tubuli is
not shown by the same decided proof as in the former instance,
viz., by the presence of sporangia, none of which were met
with. The constitution, however, of the tubuli was in this
case such, that even had they existed in all the horny fibres,
I should not have hesitated in referring them to fungus-
filaments. They present the appearance of rather wide canals,
usually in the number of 1, 2, 3, rarely more, penetrating
into the interior of the horny fibres, and giving off in their
course, at an acute angle, rather numerous branches, which
also continue to run ina longitudinal direction. Itis peculiar
that all these principal trunks give off, at right angles, a
greater or less, and sometimes a very considerable number of

-ramuscules, which run straight to the surface of the fibre,
where most of them open externally, as may be plainly seen
by the escape, in dried specimens, of the air contained in the
filaments. I could perceive no trace of sporangia within the

176 KOLLIKER, ON VEGETABLE PARASITES.

horny fibres, but on their exterior, in a few instances, opaque
rounded bodies were seated, which were probably sporangia,
but this I was unable definitively to determine. It was
remarkable also that in many places the fungus-filaments
presented large, simuous, elongated dilatations which occupied
nearly the whole thickness of the fibre.

2. PoLYTHALAMIA.

The close examination of a considerable number of sections
of Polythalamia, for which I have been indebted to the kindness
of my friend Dr. Carpenter, afforded the definite result that
in these delicate organisms also a parasitic vegetation is not
wanting. Owing, moreover, to the circumstance that in
certain of these creatures the shells, also typically contain
special systems of tubuli, it is often extremely difficult to
decide as to the true nature of the tubuli. The genera in
which vegetable parasites, which I also look upon as fungi,
have been noticed, are the following :

1. OpeRcuLtina. (Fig. 7.)

In the shells of this genus Dr. Carpenter has described two
kinds of tubes, the one fine and closely placed, which run
vertically and unbranched, in the upper and lower walls of
the chambers, and the other usually constituted of somewhat
larger anastomosing canals, which are found in the marginal
layer of the shell, whence they penetrate into the vertical
dissepiments of the chambers. That the former represent a
normal structure does not admit of the least doubt, but with
respect to the others any decision is rendered very difficult
owing to the circumstance that, together with them, very
numerous parasitic structures certainly occur. One circum-
stance, however, may be noticed which throws light upon the
matter; the fact, namely, that im certain individuals the
parasites are entirely absent, and that there are genera
possessing essentially similar structural conditions, which also
exhibit nothing of the sort. Of six preparations of Operculina,
parasites appear to be entirely absent in five, whilst in the sixth
they occur in enormous quantity. Two preparations of the allied
Cycloclypeus Australis present no structures whatever of the
parasitic kind, and the same was the case in four sections of
Nonionina Germanica. It was thus definitively proved that the
second system of tubuli noticed by Carpenter in the species
is, as it is described and figured by that naturalist, typical.

Now with respect to the parasitic fungi which were met
with in the one specimen of Operculina, they were found, in

KOLLIKER, ON VEGETABLE PARASITES. 77,

the first place, in the dissepiments, accompanying and running
among the larger tubuli of Carpenter, but secondly, also
among the finer tubuli in the thick walls of the chambers.
They everywhere presented the aspect of more or less
sinuous, irregular, branching, and also frequently anastomosing
tubes. But whilst in the former situation the canals were
rather wide, so as to measure even 0:002” to 0:003’" and more
in diameter; in the latter, fine tubuli of the same diameter as
those of the shell were the more numerous. The adventitious
tubuli, however, were readily distinguishable from the others
by the circumstance that they were spread out in a horizontal
network, and consequently ran at right angles with the proper
tubuli of the shell. Of sporangia J noticed only in one spot
some indications on a rather wide canal, upon which were
visible two rounded, opaque swellings ; but I would not venture
to assert that these bodies were really sporangia.

2. AMPHISTEGINA. (Fig. 5.)

Five sections of this genus contained fungi. They oc-
curred principally in the marginal parts of the shells, and
appeared as branched canals, about 0:002"" or 0:003'" in dia-
meter. Besides these wider canals, others of less dimensions
also occurred, which I thimk must be regarded as of the
same nature, especially on account of their horizontal and
often much lengthened course. No sporangia were observed
in this case, whilst in certain spots in those parts of the shell
which bounded the chambers very young individual fungi
might be observed, under the form of short pyriform vesicles,
whose narrow extremity was directed towards the cavity of
the chamber.

3.. HETEROSTEGINA

Contains fine-branched and, as it would appear, occa-
sionally anastomosing fungus-filaments, running chiefly in
a horizontal direction between the fine tubuli of the shell
which they thus crossed. No sporangia.

4. CaLCARINA.

Three sections of this genus contained a few fungi, repre-
sented by sometimes fine and branched filaments, some-
times by wider, short, pyriform, and elongated tubules,
aggregated in the most superficial layers of the shell, and
which probably represented a younger condition of the
other filaments. No indication of sporangia.

178 KOLLIKER, ON VEGETABLE PARASITES.

5. ORBITOLITES COMPLANATA. (Fig. 6.)

Ten vertical and horizontal sections of this genus all con-
tained numerous fungi, generally speaking of the same two
kinds as in Amphistegina. In general the wider canals were
the more numerous, and these also presented frequent dila-
tions, and were more serpentine than in the last-named genus.
The parasites were in this case also situated more in the
superficial layers of the shell, though some penetrated through
its entire thickness. Numerous young fungi were seated in
the walls of the chambers, in the layers immediately bound-
ing them, in the form of pedunculated, roundish, and pyriform
vesicles,

6. PoLYsTOMELLA.

Nine sections of shells of this form all contained numerous
fungi of the same two kinds as those in Amphistegina. Young,
undeveloped individuals might also be observed.

7. ALVEOLINA Boscit

Contained numerous, far finer fungus-filaments, with some
of greater size. Numerous young forms.

3. ANTHOZOA.

In the great division of the Anthozoa, the calcareous
skeleton of the stony corals is very frequently pervaded by
fungi, whilst in other divisions of the class I have not yet
certainly met with any parasites. My researches have
hitherto been extended only to the following genera and
species :

(a) Porites clavaria

Contains numerous, moderately-branched, fine and coarser
fungus- filaments, from 0:002” to 0:0025'", or even 0°003'”, in
diameter, and very often supporting sporangia. These occurred
only in the thicker filaments, and appeared to be rarely or
never only terminal, but some always lateral as well. So that
one filament of this kind would often be seen supporting
4 to 6 or even 8 to 10 sporangia in tolerably close appo-
sition. In a few instances the lateral sporangia were shortly
pedunculate.

(b) Astrea annularis (fig. 8)

Presents the same form of fungus, also abundantly fur-

KOLLIKER, ON VEGETABLE PARASITES. 179

nished with sporangia. The calcareous skeleton, moreover,
contained numerous elongated cavities, placed im rows, and
forming elegant feather-like figures. These appeared to be
typical of the species, since they were always present, and
were too regularly disposed to allow of their being possibly
referred to a fungus.

(ec) Oculina diffusa.

Fungus-filaments fine, scarcely exceeding 0:001’” in dia-
meter, in places much branched, so as to constitute figures
resembling a stag’s horn. Sporangia indistinct, sometimes
round, sometimes appearing to occupy long tracts on the
filaments. A great many small cavities, of irregular dispo-
sition and form, existed, which are necessarily to be referred
to the fungus-filaments, and must not be taken to represent
sections of them.

(d) Oculina. Sp.

Fungus-filaments fine, some very minute, which latter
were frequently undulating in their course. No sporangia.
Numerous opaque, minute points were noticed, which, as in
the preceding species, are also probably to be referred to the
parasitic growths.

(e) Millepora alcicornis.

As in Porites, except that the filaments, and sporangia
were less numerous.

(f) Lobalia prolifera.

Fungus-filaments very numerous, but extremely minute, so
that in most of them the canal and double contour could not
be distinguished.

Course straighter. Branches rarely seen; and the only
traces of sporangia consisted in irregular protrusions at the
extremities of the thicker filaments.

(g) Alloporina mirabilis.

Filaments still more minute, but numerous. More intimate
condition unascertainable. No sporangia.

(h) Meandrina.

Fungi sometimes rare, sometimes very abundant. Fila-
ments thick, even of considerable dimensions up to 0:006, or
even 0-008", branched. Sporangia apparently elongated,
but in my sections nowhere quite perfect.

180 KOLLIKER, ON VEGETABLE PARASITES. °

(7) Fungia.

Delicate, rather numerously branched filaments, from 0-001"
in diameter to some of extremely minute dimensions. No
sporangia.

(k) Corallium rubrum.

In four sections, only in one were observed a few fine,
evidently fungus-filaments without sporangia.

(1) Isis hippuris

Also contained only a few of rather thick fungus-fila-
ments.

(m) Madrepora muricata

Exhibited rather numerous fine, beautifully branched fungus-
filaments, with indications of sporangia.

(n) Tubipora musica.

The substance of this calcareous skeleton was everywhere
pervaded with very numerous finer and coarser fungus-fila-
ments, whose ramifications, however, presented no sporangia.

In the hard structures of other polypes, I have not yet
succeeded in detecting any parasites. Among these were
various species of Antipathes, Gorgonia, Pavonaria, Pennatula,
and Virgularia. In the two latter genera, it is true that
tubular structures occurred in the calcified axis, which have
been already noticed and figured, by Quekett, form Virgularia
(‘ Histol. Catal.,’ 1, p. 221, Pl. XIII, fig. 11), but these are
unbranched, and so regularly disposed that they can scarcely
be looked upon in any other light than as typical struc-
tures.

4, ACEPHALA.

The well-known researches of Dr. Carpenter have esta-
blished the fact that in the shells of many bivalves special
tubular systems exist, which have been regarded by that
author as typical. These tubuli have subsequently been
mentioned by Quekett, in his ‘ Histological Catalogue,’ part i,
in describing the preparations presented to the College of
Surgeons by Dr. Carpenter, but without any further expres-
sion of opinion as to their nature. In another place, however
(‘ Lectures on Histology,’ vol. 11, pp. 153, 276, 277), Professor
Quekett compares them with Conferve, though ultimately
agreeing with Carpenter, and supposing that, like the canals

KOLLIKER, ON VEGETABLE PARASITES. 181

in dentine, they have some relation to the nutrition of the
shells. In my work upon cuticular formations and pore-
canals, I remarked with respect to this subject, that certain
of the tubuli described by Carpenter very closely resembled
the pore-canaliculi of cuticular structures, among which
I placed the bivalve shells; but at the same time, I stated
that the horizontally spread and anastomosing canals
of other genera must be differently explained. Lastly, the
latest author who has occupied himself expressly with this
subject, Wedl, has described the tubuli in all bivalves as
vegetable parasites, with which opinion I now entirely coin-
cide.

The genera and species examined by me are the following:

(a) Anomia ephipprum.

To Dr. Carpenter’s description I have chiefly only this to
add, that m most of the coarser fungus-filaments rounded
sporangia, and, as it appears to me, principally terminal,
are placed. ‘To judge from two of Dr. Carpenter’s prepara-
tions, the fungus-filaments in the most superficial layers
of the shell constitute a close network, from which straighter
and less branched filaments, of greater or less size, run in very
oblique directions into the inner layers. The sporangia are
situated principally in the neighbourhood of the mycelium-
plexus above mentioned, and measure as much as 0:02” or
more.

(b) Cleidotherus chamoides

Contains, throughout the entire thickness of the shell,
numerous fungus-filaments, usually of no inconsiderable size
(0:003” or even 0:005’"), which in certain layers are much
branched, and in the outermost coloured lamina present
elongated enlargements, which can scarcely be regarded as
anything but sporangia.

(c) Lima scabra.

A horizontal section, procured from Dr. Carpenter, afforded
no distinct evidence with respect to the distribution of the
fungus. The filaments, having an average size of 0:001’” and
0:002"",ran forthe most part horizontally, some much branched
and, as it appeared, also anastomosing, some straighter and
supporting terminal sporangia, and in certain spots enlarge-
ments probably of the same nature.

(d) Arca Noe.
A section of this shell, procured in England, presented only

182 KOLLIKER, ON VEGETABLE PARASITES.

straight and tolerably regularly disposed tubuli, which agreed
in all essential points with those of the shells above noticed,
but exhibited neither branches nor sporangia, and conse-
quently could not be so definitely referred to a fungus-
mycelium. But if Wedl’s observations are taken into account,
it may be confidently stated that this is the only correct in-
terpretation they admit of.

(e) Thracia distorta

Contained a good many fine fungus-filaments, with numer-
ous ramifications. Close to many of the filaments were
large, round, finely granular bodies, which are probably
sporangia.

(f) Astrea edulis.

In a shell much excavated by Clone, the portions yet
retaining their integrity were pervaded by a greater abund-
ance of fungus-filaments than I have as yet observed else-
where. The filaments were rather closely branched, and
occasionally presented terminal enlargements, which could
perhaps be regarded only as sporangia.

(g) Meleagrina margaritifera.

A beautiful vertical section of this shell was particularly
interesting, from the circumstance of its showing that shells
with a perfect prismatic layer might also contain parasites.
These were most developed in the outermost layers of the
prismatic stratum, but in many instances through its
entire thickness, and beyond it to a greater or less depth into
the nacreous layer. The filaments were some 0:002
and 0:003’, some finer, and no sporangia were visible upon
them.

Many other bivalve shells presented no trace of parasites.
Among which may be enumerated—Pinna ingens, Pinna
nigrina, Mya arenaria, Unio occidens, the prismatic layer of
Perna ephippium, Avicula, Crenatula, Malleus albus.

5. Bracuiopopa.

The shells of certain Terebratule, besides the well-known
coarser tubes, are also penetrated by extremely minute canali-
euli, which, in respect to appearance and diameter, closely
resemble the tubuli of dentine, and can scarcely be regarded
except as fungus-filaments.

They were seen in Kraussia rubra, Terebratula Australis,
and 7’, rubicunda, for sections of which I am indebted to Dr.

KOLLIKER, ON VEGETABLE PARASITES. 183

Carpenter. The tubuli, which appear to commence on the
exterior, are rare, usually run in a ventical direction through
the fibres, but, nevertheless, present such irregularities in
their course as, together with the circumstance that in some
spots they are wholly wanting, seem to indicate that they do
not belong to any typical structure.

In Rhynchonella nigricans, Terebratula Caput Serpentis,
and T. resupinata, no vestige of these fine tubules was per-
ceptible. On the other hand, in Leptena lepis, from the
transition-formation, Wedl has found vegetable parasites.

6. GASTEROPODA.

The canals in these shells, which were first noticed by
Claparéde, have been referred by Wedl to a vegetable para-
sitic growth—an explanation whose correctness admits in
part of easy proof, inasmuch as, in certain cases, distinct
sporangia may be observed on the canals. I have examined
the following shells :

(a) Murex trunculus.

In the outermost layers of the shell may be observed a
horizontally spreading mycelium, constituted of anasto-
mosing fungus-filaments, of whose delicacy it is difficult to
form any idea, since the meshes of the plexus are in many
places hardly double the diameter of the filaments.

Very numerous straighter filaments arising from this
layer of mycelium passed inwards, penetrating all the lamine
of the shell either vertically or obliquely, and throwing off
frequent branches. On arriving at the innermost lamina,
and not unfrequently even before doing so, these filaments
would again spread out in a horizontal plexus. No sporangia
could be perceived. The fungus-filaments measured, for the
most part, about 0-001", though some reached a diameter of
0-002”.

[Other species of gasteropod shells examined by the author,
and which presented appearances more or less similar to the
above, are :|

Murex brandaris. Hahotes, sp.
Vermetus, sp. Tritonium cretaceam.
Turbo rugosus. Litorina litorea.

Aphorrhais pes Pelecani. Terebra myurus.

Whilst in species of Oliva, Cyprea, Nautilus pompilius,
and Aptychus, he was unable to detect any growths of the
fungus character.

184 KOLLIKER, ON VEGETABLE PARASITES.

7. ANNELIDA.

The tubes of two undetermined Serpule, from the coast of
Scotland, were pervaded most abundantly with fungus-
filaments, in which, however, neither anastomoses nor
sporangia could be perceived.

8. CIRRHIPEDIA.

In this division I have found structures which could with
certainty be described as fungus-filaments, only in a large
Balanus. They occurred both in living and dead shells, were
extremely abundant, usually branched, and occasionally con-
nected at the extremity with elongated, curved, widish spaces,
probably sporangia. In one instance the filaments formed
beautiful anastomoses. Besides these fungus-filaments, it
would appear, at any rate from Quekett’s description (‘ Histol.
Catal.,’ i, pp. 263—265, Pl. XVII, fig. 12), that other tubuli
occur in the shells of Balani, which are probably of a typical
nature, although from the representations of that author it is
not clear whether, among the structures described by him,
there might not be some corresponding with those I have
noticed above. Moreover in Pollicipes, as is also remarked
by Quekett, tubuli exist which, from their regular course in
distant rows, in all respects resemble a typical structure. In
the opercular pieces of Tubicinella, also, I have found tubuli
which, from their being unbranched and running parallel to
each other, resembled a normal structure. They were placed,
however, far closer together than the tubules in Pollicipes,
and I am compelled, for the present, to suspend my judgment
respecting them. The statement made by me in another
place (‘Wurtzb. Verh.,’ Bd. x), that fungi occur also in
Diadema, I must retract as erroneous. The mistake arose

from the wrong ticketing of the preparation of a gasteropod
shell.

9. Fisu.

As stated above, the observation of parasites in the scales
of Beryx ornatus, from the Chalk, was the starting point of the
investigation here recorded. The parasites of these scales are
by far the most elegant of any hitherto met with (fig. 9), and
correspond essentially with those figured by Mr. Rose. They
are unicellular organisms, constituting stars with 8, 16, or 32
rays, at the extremities of which the sporangia appear to be
developed, inasmuch as in large individuals the rays are not
unfrequently slightly clavate. Although usually there are

KOLLIKER, ON VEGETABLE PARASITES. 185

not more than thirty-two rays, cases nevertheless occur in
which the growth appears to advance still further, although I
have not yet succeeded in obtaining good views of such indi-
viduals. This form of fungus might, as I am informed by my
colleague, Professor Schenk, constitute a new genus; but I
willingly leave this to the botanists.

In the scales of living Ganoid fishes, in many of those from
fossil genera belonging to this division, which have been
placed at my disposal by Professor Williamson, as well as in
the scales of Teleostei, I have up to the present time in vain
sought for fungus-filaments, although it would seem, at any-
rate from Mr. Rose’s researches, that they do prevail to a
certain extent in these organs also.

This is the extent of my present researches. Taken
together with those of Wedl, which have also been extended
over a certain number of fossil molluscous shells, they serve
to show that in any case the occurrence of vegetable parasites
in the hard structures of animals is very frequent, and that
this phenomenon must henceforth take its place among the
certain acquisitions of science. Nevertheless, with respect to
particulars, much remains to be ascertained, and I would
direct attention principally to the following points.

1. The parasitic growths are very frequent in marine
animals, whilst they are almost wholly wanting in those
belonging to fresh water. In the latter, they have been
noticed only in Cyclas (Carpenter), Neritina fluviatilis
(Claparede), in the scales of an undetermined fish (Rose),
and in Neritina croatica and Melania Hollandrii (Wed)l) ;
whilst in five fresh-water bivalves and eight gasteropods
examined by Wedl, these growths were absent. The reason
of this is not clear. It is either to be sought in the circum-
stance that the appropriate lower plants occur only sparingly
in fresh water, or that such a difference exists in the con-
ditions of vegetation of the two kinds of plants, that those
belonging to fresh water are incapable of disintegrating the
hard parts in question. But this is an inquiry whose answer
may properly be left to the botanist.

2. Among marine animals also, the parasites are not found
indiscriminately in all. In the mollusca they are indeed so
abundant that it would almost appear that it is only by
chance that they are absent. Nevertheless it seems, as has
already been noticed by Wedl, that a thick periostracum and
the prismatic layer present difficulties to the penetration of
the mycelium which, in many cases, it cannot get over.
Moreover, the parasites are absent in chitinous structures
almost without exception, especially in those that are less
calcified (Decapods). In the strongly calcified forms also,

186 KOLLIKER, ON VEGETABLE PARASITES.

they appear to occur only in cases where an external uncal-
cified layer is not present, as in Balanus and Serpula ; whilst
in the opposite case they are absent. In corals and forami-
nifera again parasitic growths are very general, whilst in the
Spongiadee they are often wanting.

3. The penetration of the parasites appears to take place
in two ways—a mechanical and a chemical. The latter
is doubtless the case in all calcareous skeletons, in which
scarcely any other supposition can be entertained except
that the parasitic growth, as it advances, dissolves the car-
bonate of lime contained in the tissue, by the secretion of an
acid. Whether this be carbonic acid, or one of an organic
nature, must be determined by future inquiry. All that can
now be remarked is, that the supposition of the agent bemg
carbonic acid is hardly supported by the fact stated by
Bischoff (‘Lehrb. der Chemischen Geologie,’ 11, p. 1136), that
oyster shells are far more difficultly soluble in water contain-
ing carbonic acid than are chalk or powdered calespar ; and-
which is in accordance with the preservation of shells and
the other hard tissues in question in sea-water which con-
tains carbonic acid. Were it the case that the hard struc-
tures concerned contained more organic material than
at any rate the bivalve shells and stony-corals actually pos-
sess, it might also be supposed that the fungi first attacked the
organic substance (which, it is true, is very doubtful), and then
removed the carbonate of lime by the secretion of carbonic
acid. However this may be, it appears that in any case the
solution of the calcareous matter takes place only at the ter-
minal, growing end, since the fungus-filaments are never
lodged in wide vacuities, but, on the contrary, throughout their
course are closely surrounded by the hard tissue. It is also to
be remembered, that it is difficult to perceive what becomes of
the dissolved carbonate of lime. It cannot well remain in
the fungus-filaments ; whilst, on the other hand, when their
often very considerable length is considered, it is difficult to
suppose that it is conveyed through them and deposited on
the exterior; and yet any other supposition seems scarcely
possible, and the more especially as the probable existence
of a continuous reciprocal action between the water and
the filaments at the surface of the shell should not be lost
sight of.

In the case of the sponges, a mechanical penetration of the
fungi may be supposed to take place, since it is impossible
to conceive in what way they can be enabled to dissolve
such a resistant substance as the horny skeleton of these
creatures. An analogous mechanical penetration is wit-
nessed in the passage of parasites through cellulose-mem-

KOLLIKER, ON VEGETABLE PARASITES. 187

branes, and would require merely a certain displacement of
the molecules of the tissue, which certainly takes place in
moist sponge-fibres, as is obvious from their powerfully ab-
sorbent property.

4. With respect to the nature of the parasites, Wedl and
I are so far not in accord, that he describes them as multi-
cellular plants, and, indeed, as alge, whilst I regard them
as unicellular fungi. With respect to the uni- or multi-
cellular nature of the growths, I think my view is supported
by the circumstance, that on the close survey of numerous,
and more particularly of the wider canals, no trace of a
partition-wall has anywhere been perceptible. Whilst, as
to the question of their being Algze or Fungi, it is not for
me to give a reply, inasmuch as it is well known that
botanists do not find it easy to draw good lines of distinction
between the two divisions, and that the first botanical
authorities entertain opposite views with respect to certain
divisions. (Vide Nageli, ‘ Gattung. einzell. Algen,’ Ziirich,
1849, pp. 1, 2; and Verhandl. d. Deutsch. Naturf. in Bonn;
Cohn, ‘Entwicklung der niedern Algen und Pilze,’ Berlin,
1850, p. 1389 e¢ seg.; and Pringsheim in Jahr., f. wiss.
Botan. 1, 2, p. 284 et seq.) It cannot be denied that the
beautiful networks observed in many situations, and analogous
to those of the mycelium of fungi, and the mode of fructifica-
tion, appear to indicate the fungoid nature of the parasitic
growths; and I shall, therefore, for the present, describe
them as such. The naming of them I willingly leave to those
who are alone entitled to undertake it.

Norte to the above. By Dr. J. S. Bowrrsank, F.R.S., &e.

I cannot concur with Professor Kolliker in the belief he
entertains that the tubular fibrous tissue surrounding the
skeleton fibres of the pieces of sponge I gave him are ori-
ginated by vegetable parasites.

The Sporangia, figure 3 in his paper, and other similar
forms, are of common occurrence on sponge fibres, where no
such network of tubular fibre occurs, the saline matters
remaining in sponges always attracting so much moisture,
as to cause them to be abundantly infested with parasitic
forms of vegetation; but, notwithstanding these favorable
circumstances, I have never met with this curious network
but in three species of recent ceratose sponges, although
. -] have examined many hundred specimens of them. Another
fact in favour of their being really organic tissues of the
sponges is, that very similar canals occur in siliceous sponge

188 POUCHET, ON ATMOSPHERIC MICROGRAPHY.

spicula in my possession, and in these cases we cannot
reasonably attribute them to the action of parasitic forms
of vegetation.

When these minute tubuli are completely separated from
their matrix, they still preserve all the characteristic appear-
ance of ceratode, and their thickened glue-like aspect is
very dissimilar to the delicate translucent forms of minute
vegetable tissues.

The young and immature fibre of the true sponge, much
less in diameter than the adult fibre, are usually destitute of
the network of tubular structure that surrounds the others; but
this we can scarcely imagine would be the case, if it were
due to a parasitic vegetation. The adult fibres are also often
partially destitute of the tubular fibre, in consequence of
its having been stripped of the sheath that surrounds it, on
the inner surface of which these minute tubular fibres are
embedded. The stripped fibres of the skeleton may easily
be recognised by the faint diagonal lines upon them, which
are not visible through the external coat of the vegetable
fibre.

Similar tissues to those in sponges which I gave to
the author occur also in siliceous fossil sponges. These
I have figured and described in the ‘ Annals and Magazine
of Natural History,’ vol. x, pp. 18 and 84, Plate III, figs.
2 and 6, from green jaspars from India, and 3 and 4
from chalk flints. An identity of organization may naturally
be expected to occur between the recent and fossil sponges ;
but it is difficult to conceive these tubes to be effected
by parasites under such widely different circumstances of
time and place as those of the fossil and recent specimens.

ArmospHertc Microcrapny. On the Means by which all the

CoRPUSCLES NORMALLY INVISIBLE, contained in a DeterR-

“mInAaTE VoLuME of Arr, may be collected into an infinitely
SMALL Space. By M. Povucuet.

(‘Comptes rendus,’ April, 1860, p. 748.)

I wave succeeded, by means of a very simple instrument,
in concentrating, upon an infinitely minute surface, all the
solid and normally invisible corpuscles floating in the atmos-
phere, so as to allow of their being strictly appreciated and
counted. By this means we can, if we please, concentrate on

POUCHET, ON ATMOSPHERIC MICROGRAPHY. 189

a glass, and within a space of two square millimetres, all the
particles disseminated in a cubic métre of the atmosphere, or
even more.

By this new method we have proved once more a fact
which we had previously advanced. We have been enabled
to see that the spores of plants and the ova of Infusoria, as
has been equally recognised by MM. Joly and Ch. Musset,
were infinitely rare, even in situations where they might have
been expected to occur. ‘Thus, in our laboratory, where
almost throughout the year microzoa and mucedinous fungi
are continually pullulating, I have been unable, in 1000 cubic
décimétres of the air of which I have concentrated the invi-
sible corpuscles by the aid of my instrument, to find a single
infusorial ovum, nor a single spore.

The volume of air, however, just stated is erroneous, when
compared with the small quantity necessary to produce an
abundance of proto-organisms. In fact, whenever a suitable
infusion is employed, and placed in contact with not more
than a cubic décimétre of air, that is to say, with the
thousandth part of the volume explored, millions of Infusoria
or of Cryptogamia are almost always sure to make their
appearance in it.

The instrument which we employ to concentrate the
atmospheric corpuscles is constructed as follows. It is
formed of a glass tube, closed hermetically at each end by
copper stop-cocks. The upper stop-cock, which is fixed,
receives a copper tube, terminated exteriorly by a very small
funnel, whilst internally it is drawn out into a very fine point,
the opening of which does not exceed 0°50 mm. in diameter.
By the lower stop-cock a flat, circular dise of glass is intro-
duced into the apparatus, which is placed at the distance of
one millimétre from the elongated point of the tube. The
apparatus is then closed, and the interior is placed in com-
munication with an aspirator, by means of a tube which
traverses the lower stop-cock.

When the aspirator is put into action, the surrounding air
being sucked in, passes through the tube, and issuing from
its poited extremity, strikes upon the glass disc, and deposes
on its surface all the atmospheric corpuscles contained in it,
precisely in the same way that in Marsh’s apparatus the
metallic particles, issuing from it, are deposited on the plate
of porcelain. The more bulky particles all collect into a
small, central heap, which, however, does not exceed a milli-
métre in diameter ; whilst the others only radiate at a little
greater distance around it.

When the glass which has thus received the jet of air is

VOL. VIII. F Q

190 POUCHET, ON ATMOSPHERIC MICROGRAPHY.

extracted with care and examined under the microscope, there
will be found concentrated upon it, and on a surface of
extreme minuteness, all the corpuscles which float invisibly
in a volume of the atmosphere relatively immense, and which
can be accurately determined by calculation from the known
capacity of the aspirator.

In order to give the apparatus still greater precision, and
to preclude the possible escape of any corpuscles, even among
the most minute and lightest, the glass disc may be covered
with some adhesive substance. By this means every particle,
without exception, will be attached to the surface at the very
spot to which the current of air conveys it.

If it be preferred, the corpuscles may be disseminated upon
the glass disc, if the tube be terminated not by a single
minute orifice, but by a small flat diaphragm, perforated like
the rose of a watering- pot.

On the other hand, whilst my aeroscope, as it may be
termed, clearly demonstrates that that abundance of germs of
which so much talk is made, but which has never been shown,
nowhere exists in the air: by a series of comparative expe-
riments in sowing the atmospheric corpuscles, under circum-
stances favorable to the development of the proto-organisms,
I have never seen that the soil thus sowed was more fecund
than that which had not.

Nevertheless, if we were able, as is pretended, to sow
cryptogams or microzoa collected from the air by means of
balls of cotton, it is evident that every time these atmospheric
corpuscles were placed in suitable circumstances, a quantity
of proto-organisms would also be developed proportionate to
the amount of atmospheric detritus employed. But, I repeat,
experience has refuted all such pretensions.

In similar vessels, under glass-bells of the same capacity,
at identically the same temperatures and degrees of pressure,
and in equal quantity, flour-paste, sowed with atmospheric
corpuscles, has never shown itself more fecund in orga-
nisms than that which had not undergone this preparation.
This sowing was very readily effected, either by the aid of a
fine muslin tamis, to disseminate the spores, if there had
been any; or simply by the exposing of the vessels in situ-
ations where the air had been agitated, in order to secure an
abundant deposit of its corpuscles. Vessels thus sowed, and
those carefully covered over, were equally fertile. Further
than this, some Nile mud, heated for an hour to 160° C., and
reduced to powder, was not less prolific than that which had
not been submitted to that temperature. Nevertheless, ac-
cording to the opinion opposed to us, the contrary of what
we observed should have taken place. We have, moreover,

POUCHET, ON ATMOSPHERIC MICROGRAPHY. 191

sowed many other bodies, and have found, in all these cases,
that the atmospheric dust was never more productive than
they, and often even not so much so.

It seems to me, I would say im conclusion, that whenever
an experimenter asserts that he collects in the atmosphere
ova or spores of proto-organisms, he should be required to
show them. Several of these germs, in fact, are perfectly
well known. Such, especially, as divers spores of Muce-
dineze, in which certain modes of illumination discover
microscopic characters altogether peculiar; and the same
with the ova of several Polygastrice.

[The author proposes to employ his instrument for the
microscopic analysis of the air of hospitals and marshes, &c.,
and promises to communicate the results on a future occa-
sion. |

192

REVIEWS.

A Manual of the Sub-kingdom Protozoa. By JosrpH ReEay
Greene, B.A. London: Longmans.

WE learn from the preface to this little volume, that it “is
the first of a series of similar treatises on the several depart-
ments of the animal kingdom;” and from the cover of the
book we find that it is intended to herald a series of scien-
tific manuals. A manual of systematic botany is in pre-
paration by the distinguished professor of botany in the
University of Dublin. Professor Greene’s work is a capital
commencement of the series. In beginning with the Pro-
tozoa, the author had a subject of some difficulty with which
to commence, but just such a one as an ardent and in-
dustrious student would be glad to deal.

Mr. Greene does not stop to theorise, but, after a short
introduction on the general principles of zoology, he at once
proceeds to define the group Protozoa, which he makes to
include the following families :—

1. Rhizopoda, 4. Thalassicollide,
2. Polycystina, 5. Gregarinide,
3. Spongiade, 6. Infusoria.

All these groups are of especial interest to the micro-
scopist, and constitute, in fact, the great zoological field in
which he is called to labour. We cannot follow Professor
Greene through these groups to give his views of their con-
stitution, but we can cordially recommend the volume, as
giving by far the most advanced account that we know of
amongst manuals devoted to zoology. Although the author
shows that he is quite conversant with the recent literature
of Protozoa, the work bears indications of original inves-

tigation in many of the forms of animals to which it is
devoted.

1938

The Nature-printed British Sea-weeds, a History, accompanied
by figures and dissections, of the Alge of the British Isles.
By W. G. Jounstone and ALEXANDER Croat. Nature-
printed by Henry Brapsury. Vol. II, Rhodospermee,
Fam. x—xili. Vol. III, Melanospermee. Vol. IV,
Chlorospermeee. London: Bradbury and Evans.

Iw the first number of our present volume we noticed the
first volume of this beautiful work, and it is a matter of
surprise that we should be called upon to notice not only a
second, but a third volume, before the close of the year.
Such good speed is both creditable to publisher and authors,
for the work that has been done must not be measured by the
size of the volumes, but the care that has been bestowed both
on the letter-press and illustrations. The second volume
brings us to the end of the Rhodosperms, and is equally
successful with the first in giving the correct forms of these
charming sea-weeds. The third volume is devoted to the Mela-
nosperms, and here the nature-printer has had more than ordi-
nary difficulties to contend with, the thick and leathery forms
of bladder wracks, with the gigantic fronds of Laminaria,
seemed as if they would defy any attempt to induce them to
produce a presentable picture of themselves. But by selecting
young and delicate specimens, even Fucus nodosus and Lami-
naria digitata are made fit companions for those who trust
to artistic skill for a place on the drawing-room table. As in
the former volume, each nature-print is accompanied by
drawings of microscopic structure, which will be found of
great value to those who pursue their sea-side studies by the
aid of the microscope.

The second volume is dedicated to Dr. R. K. Greville, of
Edinburgh, whose classical work on the ‘Cryptogamic Flora
of Scotland’ is known wherever the science of botany is pur-
sued; and the third is appropriately inscribed to Dr. W. H.
Harvey, of Dublin, to whom all writers on the family of
Algz are so greatly indebted. Whilst going to press we
have received the fourth volume of this beautiful work, which
now forms the most complete monograph we possess of the
Algze of Great Britain. The last volume contains a synopsis,
an index, an introduction, and a bibliography.

194

Memoir on the Spermocones and Pycnipes of FiLtaAMENT-
ous, FrRuticutosz, and Fouiacrous Licuens. By W.
Lauper Linpsay, M.D., F.L.S.

Tuts very able and laborious memoir was published in the
‘Transactions’ of the Royal Society of Edinburgh, and we
call the attention of our readers to it, as affording by far the
most exhaustive account yet published of the minute struc-
ture of the lichens. Dr. Lindsay, in his papers in this
Journal, on the genus Abrothallus, and on the structure of
Lecidea lugubris (vol. v), commenced that line of investiga-
tion, which he has carried out in this memoir to a large
section of the whole family of lichens. In his introduction,
the author draws attention to some of the difficulties which
impede the progress of the inquirer in the path he has
chosen for investigation.

“ Spermogonological investigations are surrounded by many
and serious difficulties; and it is, perhaps, but justice to
those botanists who have hitherto avoided the study of the
reproductive organs of lichens here to state what some of
these difficulties or obstacles are. Prior to the introduction
of the microscope, bodies so minute as spermogones and
spermatia could not possibly have been properly studied.
But even at the present day, when microscopes abound, it
is to be feared that few of our best lichenologists are well
versed in histology and the use of the microscope. It can
scarcely be denied, further, that many botanists have been
too much mere classificators or name-givers; they have
devoted attention too exclusively to the discrimination of
species and varieties, to the neglect of minute anatomy and
physiology, as studied by the aid of microscopy and che-
mistry. Continental botanists are infinitely before us in the
latter respect; we can show little or nothing in botanical
microscopy comparable with the productions of the French
school of observers, as published in the ‘ Annales des Sciences
Naturelles,’ or to those of the German school, as given in the
‘Botanische Zeitung.’ But the possession of a good micro-
scope, facility in microscopical manipulation, and a fami-
larity with the general principles or facts of physiological
botany, are not the only requisites or qualifications for in-
vestigations in spermogonology. The observer must be pos-
sessed of unwearied patience and perseverance ; he must
expect to meet, and he must bring to his task a deter-
mination to surmount and conquer, endless difficulties
and disappointments. I have now examined carefully,

LINDSAY, ON LICHENS. 195

under the microscope, as I have already stated, many
thousand specimens of lichens from every part of the known
world, and, in a large proportion of cases, with negative or
unsatisfactory results. I have frequently examined most
anxiously several hundred specimens of a particular genus or
species—for instance, Peltigera and Siphula—without once
having the good fortune to meet with its spermogones or
pycnides. But, on the other hand, in the midst of dis-
appointments of this nature, I have been rewarded occasionally
by the discovery of spermogones or pycnides hitherto unob-
served and undescribed. It were desirable, further, that the
observer should possess an almost unlimited leisure. The
time consumed in manipulations so delicate—researches so
intricate—is incredibly great. Koerber candidly speaks of
leaving such investigations to those “die bei grésserer
Musse solche subtile Studien verfolgen konnen.* It fre-
quently happens that even a small portion of tree-bark or
rock contains several lichens belonging to the families of the
Graphidee, Verrucariea, and Lecidee. Intermixed with the
apothecia of these lichens, and with each other, may be a
variety of spermogones and pycnides. The spermogones and
pycnides may closely resemble each other in external cha-
racter, or they may differ considerably. In either case it is
often most difficult, if not impossible, at the present stage of
our knowledge on the subject, to determine to what species
of lichen each kind of spermogone or pycnide is to be referred.
This is more especially the case when the organs in question
are very minute, black, and cone-like, as in the old genus—
erroneously so constituted—Pyrenothea, which is now found
to consist almost entirely of the spermogones of other lichens.
Such spermogones and pyenides are frequently indistinguish-
able from certain Verrucaria, parasitic fungi, and even para-
sitic lichens ; and the only means of deciding as to their real
nature is by microscopical examination. Again, the sper-
mogones of some lichens, as Ricasolia herbacea and R. glo-
mulifera, and the pycnides of others, as Peltigera, so closely
resemble in external appearance the nascent apothecia of the
same species as to be indistinguishable therefrom without the
aid of a microscope.”

Dr. Lindsay defines the Spermogones as follows :

“\. External Form.—They are generally more or less oval
or spherical bodies ; sometimes wholly immersed in the sub-
stance of the thallus; more frequently partly immersed and
partly projecting on the surface of the cortical layer ; in some

* «Systema Lichenum Germanis, von Dr. G. W. Korrser.’ Breslau,
1855, p. 152.

196 LINDSAY, ON LICHENS.

cases, naked and sessile, seated on the surface of the hori-
zontal thallus, or forming the terminations of the ramuscles
in the erect fruticulose one. The immersed and semi-
immersed spermogones are plunged in the substance of the
medullary tissue of the thallus, and they are usually partly
covered by the cortical layer, and partly encircled by the
gonidic layer.”

The other organs to which he more especially calls atten-
tion in bas memoir are the Pycnides. These are described
as follows

ite Be enides of lichens may be described generally as
externally resembling in form, colour, site, &c., the spermo-
gones, from which they can be distineuished only by micro-
scopical examination. The essential difference lies in the
character of the contained corpuscles—the stylospores, though
the sterigmata also differ from those of the spermogones to
this extent, that they are almost always simple, shortish, and
stoutish, generating the stylospores only at their apices. The
pycnides consist, like the spermogones, of a —1. Capsule ; 2.
Nucleus, made up of sterigmata, with stylospores instead of
spermatia however; 3. Cavity; and 4. Ostiole. They re-
semble outwardly, and are frequently mistaken for—a. Sper-
mogones ; 6. Minute Verrucarias ; c. Parasitic Fungi; and
d. Parasitic Lecidee, such as those mentioned under the head
of spermogones. From all of these bodies they can only be
distinguished by careful microscopical examination.

ef They resemble the organs known as Phoma, Septoria,
Diplodia, &c., which, according to Tulasne, belong, as secon-
dary reproductive organs, to various thecasporous fungi.
Their occurrence, alike in fungi and lichens, is a strong link
binding together in close alliance these two great cryptogamic
families. ‘They are more plentiful in the lower than in the
higher,—in crustaceous than foliaceous, lichens,—or, in other
words, in those species most nearly approaching, in other
particulars of their organization, the fungi. __In_ crustaceous
species they usually occur as very minute, black perithecia,
resembling the apothecia of Verrucaria. But in the higher
lichens, they are frequently much larger, more closely
resemble the spermogones, and are variously coloured, as in
Peltigera and Alectoria. In the first- named genus they are
marginal, like the apothecia; in the other, they are seated
sometimes as warts on the thalline filaments, or in the axils
of their ramifications.

“ Pyenides are sometimes associated both with spermogones
and apothecia ; sometimes with apothecia alone, no spermo-
gones being present. Occasionally, pyenides and spermogones
occur without apothecia, as in some species of Strigula ; and

LINDSAY, ON LICHENS. 197

sometimes pycnidiferous states of lichens are found just as
spermogoniferous states are— without either of the other
forms of reproductive organs.

“The distinction between pycnides and spermogones is, to a
certain extent, one of convenience—one depending on the
difference in character of the contained corpuscles—not one
as yet founded on essential differences in function, inasmuch
as the function of neither can yet be said to be thoroughly
established or understood. Hence it may hereafter appear
that some organs now denominated pyenides should be really
regarded as spermogones, as those of Peltigera and Alectoria,
and perhaps, though less likely, the converse,—that some
organs now regarded as spermogones should be looked upon
as pyenides, as those of Lichina !”

The spermogones and pycnides of the crustaceous lichens
will be treated of in a future memoir. In the mean time we
are glad to find that Dr. Lindsay has undertaken to publish
a € Synopsis of British Lichens,’ in which we understand the
lichens will be nature-printed, and accompanied with drawings
of their microscopic structure, by the author.

198

NOTES AND CORRESPON DENCE.

Another Object Finder.—As a subscriber to your Journal
from its commencement, and having never before troubled
you with a communication, I hope you will not refuse
admission to one upon a subject that has repeatedly been
brought before your readers already, but which, in my
opinion, will still bear a little further consideration.

I allude to the article of “Object Finder.” Almost every
microscopist must be too well aware of the difficulty of
quickly finding some particular scale, hair, desmid, diatom,
&c., &c., with a very high power, say a twelfth or sixteenth,
when the atom which we especially desire to examine is sur-
rounded by hundreds of others, which, as we slowly roll
them over the field by means of the traversing-plates, &c.,
confuse and weary the eye, until the operator’s patience is
completely exhausted.

The difficulty, of course, is greatly enhanced when, as
is frequently the case, the embarrassed seeker is eager to
exhibit the minute particle to friends who are anxiously
awaiting his success. It is, therefore, no wonder that so
much ingenuity has been exerted to devise various means
to enable us to pounce at once upon the desired object,
without that almost interminable bungling that I have de-
scribed. But I believe they have all, more or less, been
found unsatisfactory; some depending on unsightly circles,
&c., scratched, or otherwise marked, on the object-slider
itself; others consisting of various kinds of plates, finely
graduated, the said graduations requiring to be found,
focussed, adjusted, &c., and the said plate, moreover, being
itself a separate piece of apparatus, to be looked for, and
adapted to the instrument, whenever its use may be required.

Now, all this time, there has been in existence an appa-
ratus that forms (or should form) part of every complete
microscope; and which I verily believe to be the best
“finder” that can be used.

I allude to the instrument called, in opticians’ catalogues,
a “ double ifose-piece.”

In order to shorten the labour of finding an object with a

MEMORANDA. 199

very high power, I have, for years, been in the habit of
using a low power as a finder, and then bringing the
object into the exact centre of the field (which is greatly
facilitated by the use of that neat contrivance, the moveable
pointer, without which no eye-piece is complete), change
the powers by screwing off the low power, and screw-
ing on a high one; then, on bringing down the high
power to focus, if the achromatics are truly centred (which,
of course, they will be, if the maker has done his
duty), the desired object will still be found in the centre
of the field. This mode of finding, as I can amply
testify, is perfectly effective; but the heavy objection to it is
the figgle-niggling (I like expressive words) process of screw-
ing and unscrewing. Still 1 found it far better to do it than
to waste time in the tedious hunting I have described.

Matters stood thus with me when I first heard of the
aforesaid ‘ nose-piece.” Its construction was described to
me, and it was recommended merely for what it is in the
catalogues, viz., “a ready mode of changing one power for
another, without the trouble of screwing and unscrewing.”
But I immediately saw further than that; “for,” said I, “ it
is evident to me that, if properly made, it must also be the
best ‘finder’ that can be used.”

Accordingly, having procured one, I was greatly pleased
to find my expectations amply borne out by fact; and ex-
claimed, ‘This is the very thing I have so long been wanting:
EUREKA !”

And I am in hope that I am the first who has “ found it
out ;’” I mean, this particular application of it; for, as to
the said nose-piece itself, it 1s really nothing new, being, in
fact, merely a slight modification of the venerable old “ six-
lens wheel,’ with which what we now call the “ante-
diluvian microscopes” were usually supplied. I have one
still by me, purchased more than thirty years ago; and
I have no doubt that, as the “march of improvement”
advances, we shall, in due time, have the full complement of
two-inch, one-inch, half, quarter, one-eighth, and one-
sixteenth, mounted and acting exactly on the principle of
a six-barrelled revolver.

But to come to the practical application of the matter in
hand,—the power I recommend as a finder is one of those
luxurious one and a half inch powers made by Mr. Ross,
which exhibits a beautifully flat field, of great extent; and
which I consider as low a power as we ever, practically,
require.

On focusing with this, we shall, in many cases, see at one
view all the objects on the slider; but, if not, a slight move-

200 MEMORANDA.

ment of the traversing-plates, &c., will exhibit them. We
have then merely to place the one we wish to subject to an
enormous power at the end of the “ pointer.” Change the
powers (which, by means of the nose-piece, is done literally
in the twinkling of an eye), brmg down the high power to
focus, and instantly we see the tiny speck (which before
seemed sticking on the point of the needle in the centre of
the field), now swelled out so as to fill the entire field, and in
many cases far beyond its limits; so that we must “ traverse”
it, and examine part at a time.

Oh, it is admirable! and the velocity with which it may be
done must be seen to be duly appreciated. Let any doubtful
amateur call on me, and bring his circle-finder, his angle-
finder, or his graduated plate-finder, &c., &c., and I will
undertake to convert him to the nose-piece finder in a very
short time, and so perfectly, that he will not have the least
desire to fall back upon any other.

Indeed, it would be a very amusing contest to see a meet-
ing of several sharp-eyed and nimble-fingered microscopists
trying their finders against time; each using, of course, the
same olject, and timed by the same observer from the second-
hand pointer of a watch; the watchman saying, ‘‘ Now,”
when the operator was to commence his search, and the
searcher exclaiming, “‘ Found!”’ the imstant he had centred
the object, and brought it to focus with the high power. In
order, however, to give a plate-man some idea of the superior
speed of the nose-piece finder, I will give a single example.

I took a slider of fossil animalcules, the part contaiming
the objects exposing a circle of full seven tenths of an meh
in diameter; the whole of that extent being crammed with
débris of various kinds, among which is a very fine specimen
of that beautiful object, the Craspedodiscus elegans of
Ehrenberg. Placing this slider on the stage, and focusing it
with a one-eighth, I began to “traverse” the circle; and I
may truly say, with as much care as if anxious to exhibit the
object to a waiting friend, whose time was “almost ex-
pired,” &c.

After spending full five minutes in vain, I reversed the
nose-piece, thus applying the inch and half; and I found
that I could focus the objects, find out the desired one,
move it to centre, reverse the nose-piece, and bring the one-
eighth to focus, within ten seconds. In a subsequent trial
I did the same in six seconds, or the time in which one can
moderately count ten.

I do not believe that any one of the methods usually
employed can be made to equal this.

But here an objector may say, “ Well, but after all, this

MEMORANDA. 201

nose-piece finder is not without objection; for it is “a
separate piece of apparatus, to be looked for, and adapted to
the instrument whenever its use may be required ;” and,
moreover, the screwing of it on and off will surely cause
much more of what you are pleased to term “ figgle-niggling,”
than the use of a graduated finder, &c. To this I answer,
““No,. such is not the case. There is no occasion, at any
time, to remove the nose-piece, any more than to remove
the stage or the reflector. I keep mine on at all times,
with its finding-lens, the 13inch, firmly screwed to it as
a permanent fixture; any higher power being adapted to
the other end of the revolving arm.”

This is all I have to say upon a subject which, I fear,
is very much lke that of Columbus’s egg; for I fully expect
to be told, that “any one might have seen the applicability of
the nose-piece as a finder,’ &c. No doubt of it; but the
question is, has “any one” seen it? Meanwhile, I rest in
hope that it is a new idea.

Before laying down the pen, I should like to take this
opportunity of entreating microscopists in general to urge our
opticians to direct their attention more to the Binocular
Microscope than they have hitherto done. I am persuaded
that it is capable of being brought far nearer perfection
than it has yet been. For Nachet’s instrument, though
praised by a great authority, is sadly wanting in definition ;
and the flaming account of the American improvements
(given in your Journal, No. V, p. 28), is I am informed,
fearfully overdrawn! Our English makers say the difficulty
is caused by the binocular principle reducing the angle, and
thus causing indistinctuess.

But may there not be some way discovered of getting
over this? ‘To those whose eyes are equally perfect, it is
very annoying to have to peep with one only at a time,
instead of using both at once, with as much ease and comfort
as we use an ordinary pair of spectacles. It is also the cause
of that injury to the sight of which so many microscopists
complain.—Hernry U. Janson, Pennsylvania Park, near
Exeter.

The Object Cabinet.—I have endeavoured, in the accompany-
ing drawings, to give some idea of a cabinet for microscopical
preparations that I have now had in use for some time, and have
found exceedingly convenient, from the great ease with which
any particular slide may be found, and from other advantages
which [I shall briefly point out. It may be described as
follows. Drawing No. 1 exhibits the cabinet opened out

202 MEMORANDA.

for use; and shows, in scme measure, one of its principal

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features, namely, facility of reference, which is further in-
creased by the quickness with which the several leaves can
be turned over. Drawing No. 2 is an end view of the seme,

showing some of the details of its construction, and the
manner in which the slides lie on both sides of each leaf.
It consists, as represented in these drawings, of four pieces
or leaves of thin wood, or other suitable material, having
thicker slips fastened at either side, for the purpose of keep-
ing the slides from touching one another when the cabinet
is closed. Each leaf has also, as shown in the first drawing,
three pieces of narrow elastic banding, fixed across it from
side to side; and these are divided off into the requisite
number of spaces by thread or silk passing through the
boards, thus making a separate compartment for every
object, which is kept firmly in its place by having the band
somewhat stretched in putting on. The cabinet, which from
its form may be properly called a “book cabinet,” has two

MEMORANDA. 203

light covers, and may either be fastened by an ordinary
brass clasp, or by a lock, as in the drawing; at either end is
a small leather or cloth flap to keep out the dust. The one
figured as above will contain twelve dozen objects; but by
putting eight slides in a row, anddoubling the number of
leaves, a single cabinet would hold 384 specimens: but both the
size of it, andthe number of objectsit may be made to con-
tain, is more a matter of individual convenience than other-
wise ; and where the quantity of any particular class of objects
is sufficient, separate cabinets might be had for each, as for
instance, Diatomaceze and Desmidiaceze insect prepara-
tions, &c., &c. Besides the ease of reference, which may be
further facilitated by an index (each space being numbered),
and by having particular classes of objects in separate books,
as above proposed, the cabinet can be carried about from
place to place, without in any way disturbing or moving the
specimens ; and this is sometimes an advantage, although but
a trifling one.

I have lately been given to understand that this form
of cabinet is not altogether new, and that I cannot lay claim
to having been the first to propose it; yet I have ventured to
put forward the above drawings and description, from the
circumstance of my own having met with so much approval
from every one who has seen it, and as I am not aware that
the plan has as yet been adopted or brought specially forward
in any way.—JameEs Suitu, 21, Soley Terrace, Pentonville.

A new Polarising Stage —The accompanying drawings show
two different constructions of a selenite or polarising stage,
which I have designed to obviate a slight difficulty in the
examination of objects by polarised light, viz., that of
having to alter the focal adjustment of the microscope every
time the selenite is placed under the object to be examined,
or removed from it; but by the use of either of the above
forms of stage, the particular object to be examined having
been once found and properly focused, it can be viewed, in
the first place, by the polarising prisms alone, and after-
wards with the selenite interposed, which can be exchanged
for one or more of different tints, without in any way moving
or disturbing the slide; and thus I conceive that, in instru-
ments that are not otherwise specially adapted for the pur-
pose, the various phenomena of polarised light (as applied
to the microscope) may be more easily and satisfactorily
observed.

Drawing No. 1 shows the simpler form of the stage (which,

204. MEMORANDA.

from its construction, will be of very trifling cost). It con-
sists of an upper plate with raised edges, for the purpose of

Nos I:

holding the object-slide, and an under plate on which to
place the selenite, while to it are fixed two small pins, cor-
responding to two holes in the stage of the microscope, to
attach it, when in use, to the instrument; the same object
can, however, be effected by the ordinary clamping bar or
spring, where the microscope has them, in which case the
pims would not be required. In the second form, as shown
in drawing No. 2, the selenite holder is fixed on to a small

piece of tube, which turns round in another piece fastened to
the bottom plate, and in this way the rotation of the film is
effected. A very slight modification of this form will allow of
two or three selenites being superposed where required. The
selenite stage being fixed to that of the microscope, as before
described, the necessary motions can be given by the proper
screws, when the instrument has a rackwork stage ; but where
this is not the case, the horizontal motion must be given to
the object itself, by sliding it along the top plate on which it
rests.—James SMITH.

The Collecting Bottle—The accompanying drawings show the
design of a collecting bottle for aquatic larvee, infusoria, &c.,
which may possibly be found convenient by microscopists
pursuing that line of study. It may be briefly described as
follows :

Drawing No. | shows a wide-mouthed glass bottle, round
the neck of which a strip of gutta percha is fixed, so as to

MEMORANDA. 205

form a ring, a, while attached to it is a small socket of the
same material, 8, in which the rod or walking-stick is in-

serted, as shown in drawing No. 2. A stopper or cork, also
of gutta percha, c, formed so as to admit of its easy with-
drawal when the bottle is in use, is fixed to the socket by
a piece of string of adequate length.

The bottle, when used for collecting, is fitted to the rod or
stick, as shown in drawing No. 2, and the stopper inserted in

its mouth, while the string is held on a finger of the hand

carrying the stick. The bottle may then be plunged in the

water, in any position most convenient, and guided to the

place from which the sample is required, when a slight pull

at the string removes the stopper, allows the water to enter,

carrying with it any small insects, &c., that may be near the
VOL. VIII. R

206 MEMORANDA.

bottle at the time. It will be observed that the string is
passed through a small ring at the top of the socket: this
answers the double purpose of preventing the loss of the cork
by its becoming detached from the bottle, and also of saving
the bottle itself, should it by any chance become loosened
from the stick while in the water ; for in this case, as will be
seen, it will still be held by the string and the cork to which
it is fastened. I find, however, that practically there is no
probability of this happening, as the gutta percha socket
holds the end of the stick with a considerable degree of
firmness, requiring some little force to detach it. The bottle
can, of course, be used at any time without the cork, by
simply drawing the string sufficiently tight to keep it out of
the way. I have used gutta percha in the construction of
the various parts, on account of the extreme facility with
which it can be moulded into the required shape, and as any
one can with it fit up a bottle in a short time, and at the cost
of a few pence. But, doubtless, several other materials will
suggest themselves, as convenience might place within reach ;
the socket, B, for instance, might be made of metal, with a
screw corresponding to one at the end of the stick or rod, so
as to allow of the substitution of a small net or a knife, for
cutting off pieces of aquatic plants, &c. It might be found
convenient by some to have the cork permanently fixed to
the mouth of the bottle by means of a shght spring (which
may be applied in various ways) ; it would thus be always
ready for use, and the pulling of the string would only lift up
or draw aside the cork, which, returning immediately to
its place on slackening the string, might keep in some of the
larger insects that would perhaps otherwise escape.—JameEs
Situ.

On an Erecting Prism.—The instrument represented in the
annexed cut is intended to
supply the place of the first
erecting prism constructed
by us, the use of which is
attended with some incon-
veniences. Being placed
above the upper lens, it
obliges the eye to be held
at some distance from the
focus of the ocular; sp that,
in order to obtain a view of
the entire ficld, it is neces-
sary to alter one’s position.

In the new instrument, the prism is placed between the

MEMORANDA. 207

two lenses of the eye-piece. It is formed with two penta-
gonal faces, a, B, C, D, E, and A, B, H, G, F, jomed at a
common edge, A, B, and connected at the opposite end by
two facets, c, D, G, H, and pb, £, F, G& The solid formed
by these surfaces represents pretty nearly a double wedge,
of which the edges, a, B, and pb, e, are perpendicular to each
other. The way in which the erection of the image is ef-
fected may be readily conceived. The rays emerging from
the field-glass enter by the lower surface, and are reflected at 1
upon the face A, B, H, G, F, from which they are again re-
flected upon the lower surface at the point kK, and thence to the
point 1 upon the vertical face c, p, 6, H, and lastly at the
point mw upon the other vertical face, D, E, F, G, from which
the image, normally and completely erected, is again sent
back to issue by the superior surface upon which the eye-
glass is placed. Consequently the
two surfaces, looking towards the
lenses of the eye-piece, are at the
same time surfaces of reflexion and
of transmission. All the reflexions
are total, except the first at 1.
The upper surface is coated over
the space between 4, B, H, F, and
left free between F, G, H, to allow the
image to pass.

The loss of light is inconsiderable,
owing to the energy of the con-
vergent pencil put in action in this prism, which may
be applied to magnifying powers far greater than those usu-
ally employed in the minutest dissections. The combination
represents a weak ocular; so that when the eye-piece is ap-
proached to the objective, as small a magnifying power as
may be wished is obtained.—NacuHet.

On a Dark-Ground Iluminator.—I have found, that with the
little imstrument here represented,
effects may be obtained as remarkable
as those produced by the ingenious
paraboloid of Mr. Wenham, which in
its construction demands so much care,
and is too large to be applied to certain
instruments.

Our apparatus consists of a simple
cone of glass, whose summit is di-
rected towards the mirror, and base towards the object.
This base forms a segment of a sphere, and the centre

208 MEMORANDA.

is blackened so as to prevent the passage of all direct
light to the object. The arrangement is the same as that
employed by M. Amici for the illumination of objects with
one of the colours of the spectrum, by making use of the
solar light, and making the cone more pointed, and of flint-
glass, in order to disperse the light sufficiently. Im the cone
here represented, which is made of crown-glass, the dispersion
is not sufficiently great to give coloured rays, and the images
consequently are perfectly colourless —NacuHer.

On an Oblique-Light Iluminator—In cases where a very
oblique light is required in order to see very delicate lines,
the mirror and prism of Amici are often insufficient ; or at any
rate, they demand long and tedious adjustment, even with
objectives which bring out with tolerable facility the most
difficult tests. I have found that a very simple means of
effecting this object consists in a slight modification of the
old illuminator of Mr. Kingsley. The upper lens should be
covered with a thin plate, having a perforation at the margin
of the lens, so as to allow only a very sharp pencil to strike
the object. I would remark that a notable difference exists
between the diaphragm placed below the éclairage, as is gene-
rally done, and the arrangement now proposed, which has
the advantage of cutting the luminous pencil after it has
undergone all its evolutions in crossing the lenses. This
combination has the focus sufficiently long to allow of its
employment on preparations mounted on glass of the ordi-
nary thickness. -

With the objectives Nos. 7 and 8 (7;th and th inch), the
lines on Grammatophora subtilissima, the undulating lines of
Surirella gemma, and those of Navicula affinis (Amici’s test),
are immediately resolved with the aid of this arrangement of
the illuminator. It moreover possesses the advantage of
being readily applicable to instruments in which the,stage is
so thick that it is impossible to obtain an illumination sufli-
ciently oblique for delicate researches.—N AcHET.

Amphipleura pellucida.—In examining a series of fourteen
slides of this diatom with an eighth objective, without any
accessary apparatus, I have been enabled to come to a satis-
factory conclusion that it is a sad misrepresentation to set
down the lines so high in the scale as 180 in ‘001”.

That the lines of some are exceedingly fine, and beyond
my present means of giving a numerical limit, yet a few
shells may be counted at 42, and many at 60, 70, and 80, in

MEMORANDA. 209

‘001; and I have but little doubt that Amphipleura pellucida

may be found to take rank, in point of striation, as the alpha
and omega of the lineated diatoms. Mr. T. G. Rylands, I
relieve in the ‘ Microscopical Journal,’ for October, 1859,
ery correctly observes, “‘ Having seen Amp. pellucida with
gansverse lines much more distant than the 130 to :001”
bserved in that species by the Hull microscopists.”

In the same Journal an article appears from Mr. Sollitt,
sho estimates the number at 130, along with several other
aicroscopists; but no allusion is in any place made to the
sxistence of any coarser striation.

It is hence evident, from the frequent occurrence of lower
numbers, that even Amphipleura pellucida cannot be taken
as any test of the quality of a high-power objective, since
the striation may be seen, mm some instances, with the }th,
the ith, the ith; and, I think, a 34th objective might even
resolve some of the same; with a ith I can readily resolve
some into squares of 60 or 70 in ‘OO1”.

My attention to the subject was first arrested through a
beautiful slide presented to me by George Norman, Esq., of
Hull, in which I accidentally found one Acus measuring 42
strie in 001”, the length of which was 0041". Having
also a gathering of the same, I subsequently put up a few
slides and found several others, one or two upon a slide of
similar measure, with others somewhat finer, and quite suffi-
cient to satisfy myself that a comparative coarse striation,
compared to 130, was by no means an exception ; and that,
could all the gathering be fairly resolved, I know not how
far might rather even constitute the rule, and the very fine,
perhaps, the exception.

I am apprehensive that the 130 to ‘001” is not legitimately
arrived at; that to half and quarter is not a fair means; that
vision and judgment are not matured upon this point, through
want of proper objects of comparison ; and that microscop-
ists, generally, are not yet masters of the relative develop-
ments between Nobart’s test-plate and the lined diatoms;
as, for example, whether 60 lines on the diatom are seen in
exact degree with 60 upon the test-plate, so as to decide the
question of the term of visibility—-W™m. Hernpry, Surgeon,
Hull; June, 1860.

210

PROCEEDINGS OF SOCIETIES.

MicroscoricaL Society, April 11th, 1860.

Tue ordinary meeting of the Society was not held, in con
sequence of the annual soirée having been fixed for this
evening. The company assembled in the library and hall of
King’s College. About 700 persons were present on the
occasion. There were about 150 microscopes exhibited, and
many interesting objects displayed. The walls of the suite
of rooms were covered with diagrams of microscopic objects
lent by Mr. Busk, Dr. Carpenter, Mr. Mummery, Dr.
Lankester, Dr. Wallich, and other members.

May 9th, 1860.

Dr. LANKESTER in the chair.

Col. Hennell, Rev. Edw. Crofton, and Henry Black, jun.,
Esq., were balloted for and duly elected members.

Several short communications were made, and discussions
took place.

June 13th, 1860.

Grorce Jackson, Esq., in the chair.

J. H. Dallmeyer, Esq.; J. B. Fletcher, Esq.; W. A. Har-
rison, Esq.; Geo. A. Ibbetson, Esq.; Geo. Boulton, Esq. ;
W. Vanner, Esq.; Jno. Hollingsworth, Esq. ; Capt. W. D.
Lowe; Rd. Stileman, Esq.; Albert Savory, Esq.; and Jas.
Taylor, Esq., were balloted for and duly elected members.

The following papers were read :—‘ On an improved Bino-
cular Microscope,” by F. H. Wenham, Esq. (‘Trans.,’ p. 154),
“On some New or imperfectly described Forms of Diatoma-
cee,” by Tuffen West, Esq. (‘Trans.,’ p. 147).

PROCEEDINGS OF SOCIETIES. 211

Presentations to the Microscopical Society since the Ist of
January, 1860:

January 11th.

PRESENTATIONS.
Presented by
Report of the Gonicit of the Art Union of London
for 1859 : . The Society.
Comber, On the Diatomaces “of the Neichbour-
hood of Liverpool. Paper. : . The Author.
S. Andrews,
Four Slides of Diatoms : : 9 Wo ansort
February 8th.
Woodward’s Manual of the Mollusca, and a re
plement : F. C. 8. Roper.

March Ath.

Transactions of the Tyneside Naturalists’ Field Club,

Vol. IV, Part 2 =. The Society.
Quarterly Journal of Geological Society, Nos. 60, 6 Ditto.
Journal of the Proceedings of the Linnean Society,

Wok dV. Nou . Ditto.
The Annals and Magazine of Natural History, Vol. V.

No. 27 . . The Editors.
Recreative Science, Nos. Osis and 8 ; . Ditto.
The Photographic Journal, No. 94 5 . The Editor.
Journal of Dental Science . Ditto.

Observations on the Distbation and Habits of the
Pelagic and Fresh-water Floating Diatoms. Two

Papers by Dr. G. C. Wallich . The Author.
A ator aph of the Fossil Polyzoa of the ‘Crag. By

G. Busk fe Ditto:
Quekett’s Practical Treatise on the Use of ‘the Micro-

scope. Second Edition ‘ . Purchased,
Histoire des conferves d’eau douce. Par Jean-

Pierre Vaucher : A : Se Ditto:

May 19th.

Acta Academie Novorum Actorum Academis Cxsaree
Leopoldino Caroline Germanic nature curiosorum, ¢ The Academiz.
Vol. XXVIT
The Annals and Magazine of Natural History, Nos.
28 and 29 . The Editors.
Catalogue “ British Museum” List of British Diatoms F.C.S. Roper, Esq.
Journal of Recreative Science, Nos. 9 and 10 . The Editors.

212 PROCEEDINGS OF SOCIETIES.

Presented by

Transactions of the Linnean Society, Vol. XXII,

Part4 . : . The Society.
Proceedings of the Linnean Society. Supplement to

Vol. IV, Botany . ; . Ditto.
Photographic Journal, Nos. 95 and 96 ; - The Editor.
M. P. Coulier, Manuel pratique de Microscopie . Purchased.
Gerber’s Minute Anatomy, Text and Plates . Ditto.

June 13th.

Journal of the Proceedings of the Linnean Seeiety,

Vol: Ver Neliy t : ; The Society.
Photographic Journal, No. 97 . : . The Editor.

Systema mien par C, A. Agardh : . E.C.S. Roper, Esq.

ZOOPHYTOLOGY.

SHETLAND Potyzoa. Collected by Mr. Bar.et.

(Continued and concluded.)

Fam. Bicellariide, Bk.
Gen. |. Bicellaria, Blainv.
1. B. Alderi,n.sp. Pl. XXVIII, figs. 1, 2, 3.
B. cellulis turbinatis, inferne valde attenuatis ; aperturd ovali, spind.
unica angulo externo positd instructa.
Cells turbinate, much attenuated downwards; aperture oval, a single
marginal spine at the outer angle.
Hab. Shetland, Barlee.
B. Alderi, Bk. Rept. British Association, 1859. Trans. of Sect. p. 145.
Gen. Onchopora, Bk.
1. Onchopora borealis, n. sp. Pl. XXVIII, figs. 6, 7.
O. cellulis immersis, circa marginem perforatis ; poro centrali elevato sig-
natis ; superficie subsulcato.
Cells immersed, punctured at the sides; a central raised pore on the
front of the cell; surface faintly and irregularly sulcate.
Hab. Shetland, Barlee.

As only a very minute fragment of this species occurs in
Mr. Barlee’s collection, its fuller description must be re-
served to a future occasion, and for more perfect specimens.

6. Lepralia monodon, n. sp. Pl. XXIX, figs. 3, 4.

L. cellulis, subpyriformibus, ovatis, seu ventricosis, superne libera, suberecta ;
superficie punctata seu scrobiculata ; orificio rotundo, peristomate incrassato,
sepius superne dentato.

Cells pear-shaped, ovate or subventricose below, free upwards, and raised ;
surface knitted; orifice round, peristome entire, thickened, often raised
into a central blunt tooth at the summit.

Hab. Shetland, Barlee; on shell.

On further inspection of some of Mr. Barlee’s specimens,
I have met with the above form of Lepralia, which I am
unable to reconcile with any hitherto described. From the
single specimen in my possession, the nature of the tooth-
like projection on the upper border of the mouth is not very

214 ZOOPHYTOLOGY.

clear. In some instances it would appear to be perforated in
front, as if for an avicularium, but in others it is smooth and
entire.

Sus-orp. CycLosToMATA.
Fam. Idmoneide, Bk.
Gen. Pustulopora, Blainv.
1. Pustulopora Orcadensis, n. sp. Pl. XXIX, figs. 1, 2.
P. polyzoario irregulariter ramoso; cellulis numerosis, undequague sur-
gentibus.
Polyzoarium irregularly branched; cells numerous, arising irregularly on
all sides.
Hab. Shetland, Barlee.

As this form is clearly neither P. proboscidea of Forbes,
which, in fact, from the specimen so named in the British
Museum, would seem to be not a Pustulopora at all, but a
variety of Cellepora ramulosa, nor the P. deflexa of Mr.
Couch, which appears to have a simple embranched polyzoary,
I am induced to erect it into a distinct species. But since
the species of this genus are as yet but little known, and
very difficult to distinguish, except from numerous speci-
mens, I am not sure it may not be identical with a Pus-
tulopora which occurs in the Atlantic and in the Australian
seas.

ZOOPHYTOLOGY.
Plate XXVIII.

G-Busk, del ‘W.West, imp.

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ZOOPHYTOLOGY.

DESCRIPTION OF PLATES XXVIII & XXIX.

PLATE XXVIII.
Fig.
1.—Bicellaria Alderi, nat. size. (p. 213.)
2.—Anterior view of B. Alderi.
3.—Posterior view.

(These figures are taken from drawings by Mr. J. Alder.)
4.—Salicornaria Johnsoni, Bk., nat. size.
5.—Avicularium of Sal. Johnsoni.

(From drawing by Mr. Alder.)
6.—Onchopora borealis, nat. size. (p. 213.)
7.— > 3 < 25 diam.

PLATE XXIX.
Fig.
1.—Pustulopora Orcadensis, nat. size. (p. 214.)
2— 53 aa x 25 diam.
3.—Lepralia monodon, X 25 diam. (p. 213.)
4— 4, 3 x 50 diam.

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cd »_

ORIGINAL COMMUNICATIONS.

On the OccuRRENCE Of Zoospores in the Famity DresMIDIACEA.
By Wiriiam ArcHeEr.

(Read before the Natural History Society of Dublin, Friday Evening,
February 3, 1860; extracted from the ‘Natural History Review and
Quarterly Journal of Science,’ for July, 1860.)

In bringing forward the accompanying drawings, illustra-
tive of the production in the family Desmidiacez of what I
believe to be Zoospores,—while I have to express my regret
that so many links are wanting in the history of their
formation and production,—I nevertheless feel confident
the observations will be found, even so far as they go,
of abundantly sufficient novelty to warrant my drawing
attention tothem. The singular condition which the figures
represent seems to be one of such rarity, so far as I can learn,
as to lead me to believe that this will be the first time of any
similar phenomenon being either figured or recorded in
this family—A. Braun’s account of what takes place in
Pediastrum (I believe not truly a Desmidian at all) excepted.
And although I cannot, perhaps, add much to their value by
any accompanying remarks of mine, I shall, however, have
indicated, as it appears to me, the direction in which we are
to look for, and the mode in which we are to expect here-
after, the production of zoospores, at least in Docidium,
which genus furnishes us with the example in question, as
well as perhaps in any other Desmidian genus.

This consideration leads me to believe that, before offering
anything in the way of explanation of the figures, it would be
of importance to draw attention to what is stated in books
on the subject of the occurrence of zoospores in this family.
I believe every writer in our text-books on microscopic
organisms, when touching on Desmidiaceze, states it as a fact,
that, like various other alge, they are propagated by zoo-
spores; while some go more or less into details, I am in-
duced to say, very deferentially, that I think the descriptions

VOL. VIII. S

216 ARCHER, ON DESMIDIACEZX.

or statements often given are based rather on assumption
than on actual experience, because (Pediastrum excepted) I
do not find authorities given or references made to published
figures or recorded observations. Indeed, I am disposed to
think it not improbable that, in several instances, what is
meant by the authors alluded to is another and, I appre-
hend, a distinct phenomenon, but which is described as, and,
as I imagine, erroneously called, the formation of the motile
bodies or active gonidia, known amongst the alge as “ zoo-
spores.”

It is indeed likely that, by some, arguing from analogy,
the assertion is based on the history of the propagation by
zoospores, as it occurs in Pediastrum, as described by A.
Braun (vide “ Rejuvenescence in Nature,’ ‘ Ray Soc. Pub.,’
1853). In that genus this process occurs in the followmg
manner, of which it may not be out of place very briefly to
remind my hearers :—In this plant the frond consists, as is
well known, of a cluster of cells, disposed in a single plane,
generally concentrically—the marginal ones laterally and ex-
ternally, and in some species the innermost also laterally
notched. From the cells of this frond the zoospores are not
emitted singly, as in numerous other alge, but the entire
number, formed by the subdivision of the endochrome of
each into four, eight, sixteen, thirty-two, or sixty-four, or
even one hundred and twenty-eight portions, escape from the
parent cell, still involved in its immer membrane; and it is
within this that they eventually settle down and arrange
themselves into a flat cluster, resembling that from a cell of
which they themselves originated, each zoospore becoming
one of the component, mostly more or less notched or
bidentate, cells of the new frond. These spores are called by
the German writers ‘ macrogonidia.”’ Other fronds, how-
ever, give birth to smaller, more numerous, and more active
spores, called ‘ microgonidia,’ of which the further history
after their escape is unknown. Notwithstanding that in all
our text-books, in which this genus is spoken of, it is referred
to the Desmidiacez, I have myself some time since come to
the conclusion that Pediastrum is not a Desmidian at all, and
I shall endeavour briefly to bring before you the considera-
tions which seem to lead to such a conclusion.

I am, of course, aware of the difficulty sometimes met with
in satisfactorily embracing certain organisms within the terms
of what may occasionally appear as perhaps somewhat
arbitrary diagnostic characteristics; and, while the ac-
knowledged fact cannot be overlooked, that no linear arrange-
ment can ever properly express the whole of the natural and

ARCHER, ON DESMIDIACES. 217

mutual affinities of organic objects; and while at the same
time I will not deny, in regard to certain organisms which
seem to be imcongruously united with certain groups or
families, that it sometimes happens, while our present state
of knowledge as to their nature and history is deficient, that
it is more advisable to allow the puzzling forms to remain
combined with such groups as may appear temporarily the
most convenient; nevertheless, if any organism be found
really not to agree with the characters which are common to
and appear to pervade an apparently perfectly natural assem-
blage, it would seem to me to be repugnant to a proper
classification, if it could be avoided, that it should be there-
with associated.

I shall, then, venture to delay, before entering on the sub-
ject proper of this communication, by drawing attention to the
diagnosis of this family, as given in Ralfs’ monograph, “The
British Desmidie :’’—“ Fresh-water figured mucous and
microscopic alge of a green colour. Transverse division
mostly complete, but in some genera incomplete. Cells or
joints of two symmetrical valves, the junction always marked
by the division of the endochrome, often also by a constric-
tion. Sporangia formed by the coupling of the cells and
union of their contents.” Although I have no new obser-
vation in regard to the history of Pediastrum to add, I
shall just briefly compare that genus with the foregoing
definition.

That Pediastrum agrees with the first clause of Ralfs’
diagnosis is indeed apparent.

In regard to the second clause, so far as I can make out, I
believe the complete fission into two distinct cells of any of
the component cells has not been observed ; that is to say, I
believe the number of component cells in any particular
frond is not increased after their first formation; in other
words, there does not appear to be any extension of the cell-
wall of any cell accompanied by a transverse fission. Mr.
Ralfs mentions that he did not see cell-division. I have
certainly myself, so far as my own limited experience in this
genus goes, never noticed anything to indicate the mode of
division characteristic of the Desmidiacee. By this, of
course, is not meant to be denied the subdivision of the
endochrome within the parent cell,—the necessary prelude
to its conversion into zoospores. The number of constituent
cells in a frond, of often indeed even the same species, seems,
therefore, to depend on the number of times the original
endochrome of the parent cell had become segmented, and
the consequent number of zoospores. Occasionally a frond

218 ARCHER, ON DESMIDIACEX.

may be met with in which one of the component cells is
about double the dimensions of the others, while the normal
number is deficient by one; indicating, not the special in-
crease in size of one of the cells, as compared with the others,
but rather that the ultimate segmentation of the endochrome
within the original parent cell, preparatory to being con-
verted into zoospores, was in this one instance not fully
carried out. Sometimes a few marginal cells are wanting,
which may, perhaps, be explained in the same manner ; some-
times, however, they become accidentally removed by ex-
ternal forces. Indeed, it is hard to suppose an increase in
number of the constituent cells of a frond without its becom-
ing altered from a plane to an irregular structure, such as
takes place in Monostroma, Ulva, &c., the dimensions of the
frond itself, however, expanding by a simultaneous imcrease
all over. If I be right, then, Pediastrum does not coincide
with the second clause of Ralfs’ diagnosis.

As to the next clause, an inspection of any species of
Pediastrum will manifest that the cells are not composed of
two symmetrical halves, and that in the empty cells there is
no evidence of a suture; unless, indeed, the slit or gash
occurring in those cells which have produced zoospores, and
by which they have escaped, be an indication of its existence,
while they are characterised by merely being bidentate at the
external margin of often the outside row of cells only, the
internal being frequently of undefined outline.

Lastly, so far as I am aware, conjugation has never been
seen in this genus. I have myself noticed in Pediastrum
Boryanum the cell-contents of certain marginal cells retracted
from the external wall, and massed together into a green,
smooth, orbicular, spore-like body [resting spore?] in the
centre. But as this took place, not in the neighbouring cells,
and no cells being empty or disturbed in form, it could not
be imagined to be any process of conjugation effected by the
transmission of the contents from one neighbouring cell to
another.

The diagnosis given by Berkeley, in his ‘ Introduction to
Cryptogamic Botany,’ is as follows :—“ Cells void of silex,
free, or forming brittle threads or minute fronds, increased
by the formation of two new half cells in the centre, so that
the two new cells consist each of a new and old half cell.
Spores generated by the conjugation of two distinct indi-
viduals.” The only point of difference in the above definition
from Ralfs’ is the introduction of the characteristic of the two
new half cells during division being interposed between the
old ones; but as ina few species this can only be a matter of

ARCHER, ON DESMIDIACES. 219

just inference, not of direct proof, but of which indeed there
cannot be any reasonable doubt, it cannot always be insisted
on. But as to Pediastrum, I have before intimated that, so
far as I can see, the component cells do not increase m
number at all, and therefore in that respect cannot agree with
the terms of either diagnosis.

The figured outline of the cells, often, however, confined to
the marginal series, yet wanting as they do bilateral symmetry,
seems then the reason why Pediastrum has been placed
amongst the Desmidiacee. But, whilst arguing against the
claims of this genus, as such, I own I am myself unaware of
where else to place it. Its affinity with Hydrodictyon utricu-
latum seems sufficiently striking. That plant, with what,
however, must appear questionable propriety, has been
associated with the Siphonacez (‘ Micrographic Dictionary’),
a family of which Vaucheria may, perhaps, be assumed as
typical. Possibly Pediastrum and its allies, with Hydro-
dictyon, may prove a distinct family near Volvocinacez, with
which they seem perhaps connected through Pandorina and
Gonium, by certain points of similarity in their development,
or in which at least certain parallel phases seem noticeable.

Thad written so far of the present paper some months
back, and have read it as I then wrote it. Since then I have
met with Nageli’s ‘Gattungen einzelliger Algen,’ also Al.
Braun’s ‘Algarum Unicellularium Genera nova et minus
cognita,’ where I learn that the views of Nageli and Braun
were identical with the conclusions that had forced themselves
on myself, and that those distinguished algologists had
actually long since seen fit to remove Pediastrum and its
allies from Desmidiacez, and have transferred then: meantime
to the more humble family, Palmellacece.

While, then, the object of this paper is to prove that what I
think must be looked upon as zoospores do occur in at least one
species im this family, and, consequently, may occur through-
out, and that our books are therefore not wrong in assuming
it (leaving Pediastrum out of the question), still I am inclined
to think, as I before indicated, that the statements alluded to
are founded rather on the occurrence of what I am disposed
to imagine a distinct but, perhaps, more unaccountable phe-
nomenon, than on any published record of what can be looked
upon as true zoospores, Pediastrum excepted. I allude to
what has been called the “swarming movement ” of the ulti-
mate granules of the cell-contents, a phenomenon of common
occurrence in this family. Indeed, I believe I have myself
noticed it more or less frequently in nearly every species I
have seen, and even in those undergoing division. It seems

220 ARCHER, ON DESMIDIACEX.

of more general occurrence in specimens for some time ke}, *
in the house; yet, frequent as it is, it is difficult to describe,
and almost requires to be seen to be understood. It consists
of an active, tremulous, vibratory, dancing kind of motion of
the disintegrated endochrome, broken up into an immense
number of ‘exceedingly minute non-ciliated granular particles,

at once innumerable and, I apprehend, immeasurable. Not-
withstanding all the commotion, there is no very great change
of place in the active granules themselves. They not unfre-
quently form a dense cluster together, so crowded as to ap-
pear a black mass. Sometimes I have seen these masses of
active granules abruptly bounded on one side by a straight
line, as if there were some invisible barrier preventing their
assuming a more scattered appearance (I have tried to repre-
sent this in Fig. 1); but shortly thts abrupt line becomes
broken, and the cluster loses this appearance, and becomes
gradually thinner. I have noticed a very similar movement,

though less active, in various other algze, and in @erminating
spores, which had already commenced to elongate. Amongst
the Diatomaceze (in Hpithemia turgida, and im a species of
Cymbella), I have seen the endochrome throughout the frus-
tule to each extremity entirely disintegrated into nearly equal
and extremely minute and free particles, and these exerting a
very vigorous, tremulous, dancing movement, perfectly iden-
tical with what is alluded to in the Desmidiacez, and, so far
as I can see, in no way to be mistaken for the movement of
the bodies described by the Rev. E. O’Meara in Pleurosigma
Spencerii—(vide Proceedings of last session, ‘Nat. Hist. Rev.,’

vol. v, p. 192), alluded to, “howev er, as anthozoids, but more
probably zoospores), and in Epithemia Argus, E. gibba, and
Cocconeis pediculus, at our last meeting. A similar movement
of the ultimate granules, which appear brown and quite dead
in various organisms, is sometimes noticeable. This, then, in
all such examples I should be inclined to imagine is a mani-
festation of the phenomenon called “ molecular movement,”
similar to that noticeable in the granules of the fovilla of
pollen in the flowering plants, or to that seen when a small
portion of the substance of the common fresh-water sponge
is crushed down and viewed under the microscope (and of this
other examples might be cited), and rather in the cases so
common in the Desmidiacez, and in the very rare examples
referred to in the Diatomacez, indicative of decay, than as
the precursor of a further developmental change. I do not,
of course, include the singular movement of the free, active
particles at the extremities of Closterium, Docidium, &c.,
which, as every specimen of the species in which it occurs

ARCHER, ON DESMIDIACEZ. 221

exhibits it, must be normal; this may, however, possibly be
due to some modification of the same molecular law, com-
bined with internal currents.

In alluding to mternal currents I may mention that I
believe this phenomenon occurs in a greater number of
Desmidian species than is generally supposed, bat ordinarily
in very many it seems to be very rare. Clostertwm Lunula
and Penium digitus, as is well known, scarcely ever fail to
show it. But, besides, I believe with care it can be some-
times seen in other species of Closterium, as well as other
genera besides. I have never seen the rotation, as it is
called, more vigorous or more active in any vegetable cell
than I have sometimes, though by no means always or often,
seen it in Closterium didymotocum, where the granules, car-
ried onwards by the current, chased each other, with great
vigour, round and round the margin of the cell, up one side
and down the other, in a manner scarcely comparable to the
fitful and irregular currents in Closterium Lunula. Again, in
Micrasterias denticulata I have noticed a few loose granules
carried by the current, to travel up and down from one sub-
division of a lobe to another, following thus the very zigzag
course produced by the deeply incised margin of this species
for two or even three of the subdivisions; when, not being
then carried any further round the margin, they were diverted
again towards the middle of the frond and joined in the
guadrille (I can think of no better word) there performed by
other free granules, until, perhaps, again carried off to the
margin, or a few different granules being drawn off in their
place. I have noticed similar circulating currents in Cosma-
rium Ralfsii; in this species, however, the segments, unlike
Micrasterias, being not incised, the granules were carried
round and round in an uninterrupted stream. This vigorous
current, however, is very rare; yet I half think I have been
able to see currents of the fluid contents im certain Closteria
and others, where, at least, it was not evidenced by its car-
rying any granules with it. But, be this as it may, although
I have very frequently witnessed the phenomenon of the
active vibratory particles alluded to in very many species, I
have never once seen them escape by any normal process.
It is true, that when the frond is artificially ruptured, they
still, for a time, maintain their movement, though generally
less actively; but I have also noticed many of the granules
of the general mass of cell-contents, broken up by pressure,
themselves to set up a very similar movement, perhaps not so
active, though before, of course, they were still.

But if further evidence were wanting to prove the point in

222 ARCHER, ON DESMIDIACES.

question, I will mention what to me appears to be conclusive ;
and that is, that in a number of specimens of Cosmarium
(Euastrum ?) sublobatum, also of Cosmarium Botrytis, which
had been ‘ mounted” a fortnight, and which we must sup-
pose to have been dead, I have witnessed the granular cell-
contents exhibiting the “ molecular” movement as actively
as it occurs in the living frond; and this might have been
kept up while I write, possibly, had not the preparation be-
come spoiled at the end of the period mentioned.

Such, then, is, I apprehend, the phenomenon which may
have given rise to the following passages: ‘ British Desmidie,’
p- 9, Introduction: ‘ When the cells approach maturity,
molecular movements may be at times noticed in their con-
tents, precisely similar to what has been described by Agardh
and others as occurring in the Conferve. This movement
has been aptly termed a swarming. . . . When released
by the opening of the suture, the granules still move, but
more rapidly and to a greater distance. With the subsequent
history of these granules I am altogether unacquainted, but
I conclude that it is similar to what has been traced in other
alge.’ This brief passage is all Mr. Ralfs, in his work, has
to say on the subject; but, although cautiously expressed,
it would appear he looked on these minute granules as pro-
bably zoospores, and it is, undoubtedly, the same pheno-
menon to which he alludes. Hassall, ‘ British Fresh-water
Algze,’ p. 340 :— The second method is, assuredly, the usual
and legitimate mode of reproduction, viz., that by bodies
analogous to zoospores.” This statement surely appears to
be founded on the molecular movement of the minute swarm-
ing granules, as Braun’s account of the phenomenon in
Pediastrum was not then published. It may, however, be
based on Morren’s account of the development in Closterium,
to which I shall presently allude.—Berkeley, ‘ Introduction
to Cryptogamic Botany,’ page 121:—‘‘ Another mode of
increase is from the swarming of the grains of the endochrome,
which becomes individualized as in other alge, and so give
rise to a new generation. These bodies are figured, with
filiform appendages, in Pediastrum granulatum.” ‘The first
sentence of the foregoing seems to infer that the author
looked upon the swarming granules as zoospores, but it is,
perhaps, explained by the second, and the statement may
be based on what occurs in Pediastrum.—Carpenter, ‘ The
Microscope and its Revelations,’ Ist ed., page 291 :—‘‘ Many
of the Desmidiaceze multiply after another method ; namely,
by the subdivision of their endochrome into a multitude
of granular particles, termed gonidia, which are set free by

ARCHER, ON DESMIDIACER. 223

the rupture of the cell-wall, and of which every one may
develop into a new cell. These ‘ gonidia? may be endowed
with cilia, and many possess an active power of locomotion,
in which case they are known as ‘ zoospores;’ or they may
be destitute of any such power, and may become en-
closed in a firm cyst or envelope, that seems destined for
their long-continued preservation, in which case they are
designated as ‘resting spores. —The movement of the zoo-
spores, first within the cavity of the cell that gives origin to
them, and afterwards externally to it, has frequently been
observed in the various species of Cosmarium, and has been
described under the title of the ‘swarming of the granules,’
from the extraordinary resemblance which the mass of moving
particles bears to a swarm of bees. The subsequent history
of their development, however, has not been fully traced out ;
and this is a point to which the attention of microscopists
should be specially directed.’ With great diffidence, I
venture to suggest that the statements in the foregoing
passage must be based on the swarming movement of the
minute granules which I have endeavoured to describe above.
I am disposed to believe that the granules which the author
terms gonidia are not ciliated; and, although the species
of Cosmarium often show the movement, it is by no means
confined to that genus, but may be frequently seen also in
multitudes of other species. The author then goes on to
describe the formation of undoubted zoospores in Pediastrum.
As to ‘resting spores,’ I imagine he must allude to such
bodies as are figured by Ralfs in Desmidium Swartz (‘ Br.
Des.,’ tab. iv, f.), where they are not produced by conjuga-
tion, but seem to be due to the consolidation of the contents
of each individual joimt, which becomes enclosed in its own
special envelope, as sometimes takes place in Spirogyra,
&c. Braun suggests that the filament met with by Ralfs
may have been one which had entered into conjugation with
another filament, and that the string of empty cells had been
torn away; but this is certainly not the case, for I have
myself met with the species in question in some abundance
in precisely the same condition as that figured by Ralfs,
and which consist in the cell-contents of a greater or less
number in immediate succession of the cells of certain fila-
ments becoming retracted to the centre of the cavity of each
cell, and becoming there massed together into a definitely
bounded spore-like body, without any process of conjugation
or union of the contents of distinct cells. But I was not
able to see any further development, and the specimens soon
died. (Vide also, for resting-spores (?) ‘ Micrographic Dic-

224 ARCHER, ON DESMIDIACE.

tionary,’ Pl. vi, Fig. 3 B; also‘ Proc. Nat. Hist. Soc. Dub.,’
1858-9, Pl. i, Fig. 14—irrespective, of course, of the external ©
abnormal condition).—The ‘ Micrographie Dictionary’ de-
scribes only the zoospores in Pediastrum as an @ priori argu-
ment for their occurrence in the Desmidiaceze generally,
assuming, erroneously, that genus as belonging to the
family.

A recapitulation of this sort would, however, be imcom-
plete without reference toa communication by M. Ch. Morren
m ‘ Annales des Sciences Naturelles,’ tom. v, p. 266, 1836—
‘Mémoire sur les Closténiées.’? In looking over the present
subject, I met with Professor Smith’s paper on the “ Conju-
gation of Closterium Ehrenbergw’ (‘ Annals of Natural His-
tory,’ second series, vol. v, p. 1), and therefore necessarily
with that by M. Morren alluded to; and it seems to me impos-
sible not to coincide in the conclusions of the former on the
points in consideration, and consequently to look upon those of
the latter as founded in error. I shall endeavour briefly to state
the views of Morren, as founded on his observations on Closte-
rium Ehrenbergit. He believes that in the mature and merely
vegetating plant the endochrome is evenly distributed through-
out its entire cavity, and formed of extremely small granules
(“ utricles’). By-and-by, however, there appears, towards
the middle of the frond, one or many darker longitudinal
regions, which soon become bands, subsequently changmg
to be diaphanous, when the “utricles’” become larger and
spherical, sometimes disposed in a single series, sometimes
in several, and these, he says, are nourished and increased in
size at the expense of the surrounding smaller granules.
These larger “vesicles” he now denominates “ propagules,”’
and states they ultimately make their escape from the
parent frond by its dehiscence at the central suture, or are
protruded, along with the remaider of the endochrome,
en masse through a pair of apertures on the under side of the
frond. But further—he believes that the active granules
found at the extremities of this plant (as well, indeed, as in
all the species of Closterium, and in some species of a few
other genera), preparatory to the emission of his “ pro-
pagules,” leave their position at the extremity of the frond,
and, becoming mixed with them, exert a fertilizing function
on the latter. The subsequent ‘development of these “ pro-
pagules” he states to consist in their gradual elongation from
their original spherical form; the endochrome, with the
gradual increase in size of the now young growing frond, be-
coming separated into two portions, the terminal spaces with
the active granules soon making their appearance as in the

ARCHER, ON DESMIDIACEX. 220

adult Closterium, and further increase in dimensions follow-
ing, until the full size of the species is attained. He, more-
over, describes the act of conjugation (since accurately de-
scribed by Smith, /. c.) ; but, strange to say, he (M. Morren)
does not seem to look upon this as a true generative act, so
far as I can judge, but seems to think the sporangium (‘ semi-
nule’”’) resulting from the act of conjugation is itself ferti-
lized during the process by the agency of the at first terminal
motile particles. He states the further development of the
spherical sporangium (itself as great in diameter as the old
frond), previously undergoing a revolving motion for a few
moments, to consist merely in its gradual elongation in two
opposite directions, but unequally, thus forming two unequal
cones. It is to be supposed, however, that he must imagine
the smaller cone would eventually keep up with the longer,
so as to restore the symmetry. Such is, briefly, Morren’s
account of the reproduction in this plant.

Professor Smith (/. c.) gives a nearly similar account of the
process of conjugation. The conjugative act in this species is
not undertaken till after the two original fronds about to cén-
jugate have undergone self-division in the manner usual in
this genus—that is to say, by self-fission, effected by a divi-
sion of the contents into two just under the suture, accom-
panied by a development of new cell-wall to each old segment,
and separation taking place. The separated portions have
now one long (and old) cone, and one more blunt and rounded
(the nascent younger one). Now, in those individuals about
to conjugate, from each of the shorter or younger cones is
protruded a blunt, pouch-like projection from the lower and
opposed sides of each, which approaching by gradual growth,
the contents from each emerge thereby, and, meeting half
way, amalgamate with each other; at the same time the
other opposite portions of the original parent fronds doing in
precisely the same manner. Thus two sporangia ultimately
result from the two original fronds, conjugation taking place
between each of the opposite individualized pairs of partially
old, partially new, fronds—themselves resulting from the
self-division of the original parent fronds. A parallel pheno-
menon is furnished in the process of conjugation by Closteriam
lineatum, as well as by several diatoms. Professor Smith was
not able to see any further development of the sporangium,
and the propagules of Morren, he believed, had no existence
in fact.

I believe the explanation of Morren’s statement to be
possibly something like the following:—From researches of

ecent date in regard to the after development of the sporan-

226 ARCHER, ON DESMIDIACER.

gium in the Desmidiacee, it would seem that it is by a
repeated segmentation of the contents into a definite number
of portions, these becoming set free by the bursting of the
cell-wall of the sporangium, and ey entually growing larger,
and, ordinary vegetable growth supervening, assuming “the
characteristic form of the species, that the species is “itself
perpetuated (Vide Hofmeister “On Reproduction in the
Desmidize and Diatomez,” translated in ‘Annals of Natural
History,’ January, 1858; also, De Bary, ‘ Untersuchungen
tiber die Familie der Conjugaten, Zygnemeen und Desmi-
dieen,’ taf. vi, figs. 12—24, and35—46). “Now it seems probable
that Morren’s “ large vesicles” were but the starch granules
common in these species, and that they were set free but by
the accidental fracture of the frond; that his germinating

“‘ propagules,” stated to produce the plant by gradual exten-
sion and growth, were most likely ger minating sporangia,
after the contents had undergone segmentation into a number
of separate portions; that the fronds with unequal cones,
supposed by him to result from the unequal growth of the
sporangium, may have been merely detached and accidentally
unconjugated fronds, after having undergone self-division. It
is true that this explaining away of his statements leaves the
function of the active terminal granules in Closterium still
unexplained ; but I apprehend the true generative act in these
plants is to be sought, and is found, in the act of conjugation
itself. But, even admitting the correctness of Morren’s ac-
count, and that there might be two modes of true generation
in these plants, still his “‘ propagules”’ could hardly be looked
upon as zoospores, as these latter bodies, in what I believe
the strict and proper sense of the term, do not undergo fertili-
zation at all,and are ciliated and motile. I may remark, it is
possible the statements I have quoted from various works
may be based on Morren’s account just alluded to, yet I do
not find references made to his memoir (written in 1836). i
may add that Smith (/. c.) comes to the conclusion to which
I had myself arrived, and which I ventured ere now to express
(Nat. Hist. Review,’ vol. v, p. 240), that the swarming
particles are not zoospores, and not connected with the
development of the species, and I am much pleased to find
my Own previous ideas coinciding with those of so experienced
an observer.

There is only one other record which seems to bear at all
on this point, at least which I have been able to gather, and
it is questionable whether it refers here. I allude to Ehren-
berg’s figure, given in his work ‘Die Infusionsthierchen,’
Plate ii, Fig. 15, where a number of green zoospore-like bodies

ARCHER, ON DESMIDIACEX. 227

are figured within and external to an empty Closterium ; these
bodies, named by him Bodo viridis, and classed amongst the
Infusorial (“ polygastric”’) animalcules. Near the centre of
the figure, within the nearly empty frond of the Closterium,
there is a green, irregular, rugged mass. Could this be a
portion of the granular endochrome untransformed into
“ zoospores ’’—his animals of the species “‘ Bodo viridis” ?
Having thus endeavoured to convey what I believe is
the state of the question as to the occurrence of zoospores in
the family Desmidiacee, I will next draw attention to the
accompanying figures (Plate XI, Figs. 1, 4). Docidium Ehren-
bergit here affords us an example of the production of a
few comparatively large ciliated bodies formed at the expense
of the cell-contents of the parent cell, and which make their
exit therefrom through one or more specially formed lateral
tubes. These bodies, although I am quite ignorant of their
after development, I cannot but believe to be zoospores ; and
I imagine [I am justified in the conclusion, their appearance
and mode of formation seems to be so comparable to the
zoospores in Cladophora, where they undoubtedly, as is well
known in this as in various other alge, propagate the plant
and form young colonies in abundance. The first indication
of the commencement of the phenomenon is the production
of a single minute hyaline lateral tubercle, or sometimes of
two, or more rarely still of three such tubercles, just under
the inflation at the base of, I imagine, the younger segment
(Fig. 1). This tubercle arises—and the same holds when
there are two or three—not from any part of the original
segments, but from a special extension of the boundary wall
interposed between the inflated base of the segment and the
sutural line. In other words, the tubercle is not produced
between the segments by their separation at the suture, but
from an extension or addition at the base to one only of the
segments. On looking at the drawings superficially, it might
appear that the new growth, with the projecting lateral
extension, was a modification of the phenomenon some
cases of which were figured and described by me in our Pro-
ceedings of last session (Figs. 10 to 15),* here merely
differently carried out with a definite end to meet a special
exigency. But the case is different here, for in the abnormal
growths alluded to (/. c.), the new irregular portions were
added between the old segments by their separation at the
suture, making a third development specially belonging to
neither old segment ; whereas here, as I have just indicated,

* «Nat. Hist. Review,’ vol. vi, p. 469, Plate xxxiii, figs. 1O—15.

228 ARCHER, ON DESMIDIACER.

the new addition is an extension to the base of one only of the
original segments. The growth of the additional lateral tube
in the present mstance is comparable rather to the somewhat
similar extension from the shorter or younger cone, prepara-
tory to conjugation, in Closterium Ehrenbergii, described a
little back, except that here it is usually longer (or more than
one), and gives egress to separated portions of the endochorme,
individualized as zoospores, and not permitting it to extrude
en masse for the purpose of conjugating with the contents of
a neighbouring frond; thus we not unfrequently observe in
nature modifications of similar means conducive to different
ends. When the segment gives rise to one tubercle only, this
additional growth is gradually developed more and more
narrowly, diminishing to nothing at the opposite point of the
cylindrical segment, so that the frond is thus thrown out of its
straight or nearly straight direction, and becomes bent into
a knee-shape (Figs. 2 and 3). Such is also the case when
two projections arise side by side. But when two originate
opposite to each other, or when there are three, the frond is
not thrown out of its straight form, because the new addition
to the segment, from which these lateral growths take their
origin, now forms an annular extension equal all round, and
the segment therefore becomes added to in length by just
so much as the annular addition is broad—and this is less
than the 1-3000th part of an inch (Fig. 4). As the case is
pretty similar whether there be one, two, or three of these
lateral growths, I shall continue my remarks upon those cases
where one only is formed. The basal tubercle now gradually
elongates, and becomes a tube in direct connection and con-
tinuation with the frond (like the finger to a glove), and is
about 1-3600th of an inch in diameter, but of very varied
degrees of length (Fig. 2). I have noticed some to cease to
grow after having barely attained about 1-10th or 1-8th part
of the length of the frond, and I have seen a few very long,
almost, if not quite as long as the frond itself. The endo-
chrome near the base of each segment, and in the neighbourhood
of the lateral tube, next becomes very finely granular, of an
almost homogeneous appearance, and the lateral tube is filled
by it. The remainder of the endochrome (even in the state
indicated by Fig. 2) is still but little altered from the ordinary
condition, and the terminal cavities with the active granules,
characteristic of this genus, as well as of Closterium, remain
unchanged. The annular addition and the lateral tubes
are quite’ smooth, and destitute of the scattered puncta
which characterise the empty frond in this species (Figs.
3, 4).

ARCHER, ON DESMIDIACER. 229

Now it is, I apprehend, not a little worthy of remark that
the swarming, active, disintegrated granules disassociated
from the rest of the endochrome, described above as of fre-
quent occurrence, are met with at this stage, as well as
frequently at the stage indicated by Fig. 1, when the lateral
tube first appears as a mere tubercle ; and, moreover, presents
precisely the same appearance and conditions that other
specimens of this species (D. Ehrenbdergit) on the same slide
exhibit, but which are not destined to undergo the other
changes here described. Further, numerous other species,
which occurred in the same gathering, presented similar
examples of the molecular swarming movement; for example,
Docidium clavatum, Gonatozyon Ralfsii, various Cosmaria,
&e. But I think it is not less equally worthy of remark, that
other specimens undergoing the peculiar development, of
which the production of the lateral tube is a stage, did not
indicate any molecular or swarming movement of the
minute granules of the endochrome—that in the terminal
spaces, of course, excepted. On the whole, then, it does not
appear to me that these swarming granules had anything
specially to do with the production of the very different motile
bodies now to be described.

I have before stated that the endochrome near the base of
each segment, and filling the lateral tubes, becomes very
finely granular ; it next becomes segmented into a definite
number of rounded portions, or “ gonidia.”’” I was never
able to count them exactly, but I suppose they were not less
than twenty, nor over fifty ; nor did the fact of there being
either two or three lateral tubes developed seem to indicate
any very great addition to the number of these bodies. That
portion of the endochrome not thus transformed into gonidia
lying beyond them, and extending to the ends of the segments,
by this time loses its normal character, and seems to become
drawn into detached bands or strings, with a few free
granules, and the terminal cavity, with the active particles,
becomes lost. The gonidia lately formed at the middle of
the frond have now emerged through the opened apex of the
lateral tube, and remain clustered together ina mass very
much like a bunch of grapes, the clusters becoming, by
degrees, larger and larger, until all the gonidia make their
exit through the tube, and each adds its quota to the group
(Fig. 3). The same is the case when there are two or three
tubes, the only difference being that a fewer number, but
generally about equal, make their way through each (Fig. 4).
Meantime, the unused endochrome, which had become drawn
into detached strings, now loses its bright-green colour,

230 ARCHER, ON DESMIDIACE.

changing somewhat to an olive, finally turning brown, and
quite dying, and even, to a great extent, disappears (Figs. 3,
4). Each of the gonidia forming the external cluster appears
by this time to have formed for itself a special cell-wall of
slightly compressed or elliptic form, within which the green
contents may often be seen somewhat retracted. Now, a
movement within its circumscribed prison may be seen on
the part of the contents of a few of the gonidia, which takes
the appearance of a twisting motion, backwards and forwards
as it were, on its axis, similar to what may be sometimes
seen in the organisms called Trachelomonas by Ehrenberg.
I have not noticed them to turn completely round. These
gonidia are, however, greatly smaller, nor could I perceive
any red spot. If such a comparison might not appear wholly
out of place, I would be induced to say that the movement of
the green contents within the confinmg membrane reminded
me somewhat of the movement of the eye in certain Ento-
mostraca. This movement is not apparent in all the whole
group of gonidia simultaneously, but only in a few at a time.
Eventually, one by one, the green contents leave the confining
membrane in which they have hitherto been detained; but
my observation being here incomplete, and my avocations
calling me away, I am unable to say in what manner they
made their exit. There certainly appeared no neck-like
opening or perceptible aperture, but they probably emerged
by rupturing the boundary wall. Having, however, made
their escape, they swim away as ovate or pyriform ciliated
bodies, pale at the narrower or pointed end, and green other-
wise throughout—in point of fact, veritable motile gonidia,
or zoospores, in every way comparable to the similar bodies
found in other alg (Fig. 4); their principal distinction from
those, for instance, in Cladophora, being their temporarily
abiding in a cluster, each encysted in its special coating. I vainly
tried to satisfy myself whether these zoospores were one or
two-ciliated, but I was not able to decide this difficult point.
They were about 1-3600th of an inch in their narrower
diameter, and somewhat greater longitudinally. Having, one
by one, escaped, the vacated cells remain not long attached
at the apex of the lateral tube, and I think they fall away there-
from sometimes in a more or less connected condition, and
finally decay. The old frond now generally separates at the
suture, one segment bearing away the empty special struc-
ture described, the other, of course, unchanged; any
remaining endochrome by this time being quite brown,
broken up, and dead, if indeed it be not altogether vanished
(Fig. 4). Limagine it may be possible that in the native

ARCHER, ON DESMIDIACE. 231

pool the whole of the endochrome might become used up in
the production of the zoospores, as the course of nature may
have been more or less arrested under the conditions to which
the gathering had been necessarily subjected. The empty
cell-membranes, or old segments, were to be found for some
time afterwards in the gathermg, when all traces of the
zoospores had completely disappeared ; and I may add, that
the formation of zoospores occupied only two days when
there was a complete cessation of their development. I may
also add that the gathering, nm which the phenomenon I have
been endeavouring to describe occurred, was made in Septem-
ber last.

A glance at the figures will be quite enough, as it seems
to me, however imperfect my own description may be, to
prove that the phenomenon in question cannot be mistaken
for any development of the parasitic growths Pythiwm
entophytum (Pringsheim),* or of any species of Chytridium
(Braun), although a hurried reading might possibly lead to
such a conclusion. These organisms consist of colourless
pyriform or flask-shaped bodies, with a more or less elongate
neck,—in the former instance originating, in greater or less
numbers, within the cavity of the cell attacked, and protruding
their necks through its external wall,—in the latter, seated
externally wpon it—and both producing and emitting very
minute zoospores through their opened apices. Be these
curious growths antheridial structures or true parasites, which
latter, | apprehend, is most likely, there does not seem much
danger of confounding that form placed under Braun’s genus
Chytridium with the phenomenon in Docidium above
described, but a mistake, so far as regards Pythium ento-
phytum (Pringsheim), seems, perhaps, more worthy guarding
against. For a figure of this plant attacking Hremosphera
viridis (De Bary) (= Chlorosphera Oliveri, Henfrey), see
“Micrographic Dictionary,’ Pl. xlv, Fig. 8. It has, also,
been noticed by Carter attacking the cells of Spirogyra, by
Brébisson infesting various Desmidiacez, and is sometimes
met with in Closterium lunula. In Pythium the several
distinct parasites seem to be nourished at the expense of the
contents of the infested cell, presently protruding their
tubular necks through its boundary wall, outside which they
burst at their apices and discharge exceedingly minute
“ zoospores,” formed from what has now become their own
proper cell-contents, which are not green; whereas, as above
indicated in the phenomenon in Docidium, now here for the

* © Annales des Sciences Naturelles. Bot.,’ 4 Ser., tome xi, Pl. fs fic,
VOL. VIII.

282 ARCHER, ON DESMIDIACEX.

first time described, the tubular extensions are produced
directly from an addition to the original cell-wall itself, and
with which they are in absolute continuation, and through
the apices of which the cell-contents of the frond are emitted
by its own direct conversion into zoospores, and which are
green and comparatively large, after the manner of Cladophora.
Pringsheim seems to see little difficulty in supposing it as easy
for the zoospores in Pythium, having arrived at the surface
of a suitable confervoid, to penetrate or absorb their way into
the cell, as it is for their tubular necks in a similar manner
eventually to protrude from within through the outer wall.

I have, however, lately met with a parasitic growth
attacking Closterium lunula, and which I refer doubtfully to
Pythium (Pringsheim), and of which Fig. 5 is a drawing.
Pringsheim’s plant, met with by him in the conjugated joints
of a Spirogyra, he refers to the family Saprolegnieze. That
observer suggests that a ramification of this parasite may
exist in the interior, so that the numerous projecting utricles
may possibly be connected amongst themselves within the
remains of the cell-contents of the infested Spirogyra.
Therefore, he says that the bodies with elongated necks may
actually be the sporangia, each separated from the vegetative
part of the plant by a septum placed deeply beneath the con-
tents of the infested Spirogyra-spore. This, however possible it
may be in Pringsheim’s plant, does not seem to hold in the
curious growth figured (Fig. 5). Here, at least, each indivi-
dual plant seems to be a flask-shaped body, without any con-
nexion with its neighbours: in one case, indeed, I noticed
two of the necks, before penetrating the boundary walls, to
inosculate within the frond of the Closterium. In a word,
each flask-shaped body, so far as I can see, may be said here
to combine in itself both the vegetative, as well as the fructi-
fying portion ; the whole plant at maturity being, as it were,
converted into a sporangium.

In the earliest condition in which I saw this plant, the
bodies within the Closterium appeared rounded vesicles, each
with a short neck. The neck of each, by gradual extension,
reaches the old cell-wall of the Closterium, penetrating which,
it grows to a very considerable extent into the surrounding
water. Just within the boundary wall of the Closterium,
each shows a very decided globular enlargement of the neck.
So far it appears to agree with Pringsheim’s Pythium. But -
it differs therefrom, inasmuch as the cell-contents are green,
not colourless, as well as in the great length of the necks and
intheextremities, whileeach plant is filled with itsendochrome,
being distinetly clavate.

ARCHER, ON DESMIDIACE. 235

Now I regret I am unable to affirm that the numer-
ous orbicular, spore-like bodies in the neighbourhood
(Fig. 5) are the produce of the contents of the organism
in question, as I did not see their formation— but I
cannot doubt it. When I made this particular gather-
ing, I did not meet the Closterium so affected in numbers
sufficient to make any definite observations ; but I suppose
the plants must have given birth to ‘and emitted their con-
tents in the form of the gonidia lying about. For, certainly,
the bodies scattered around did not occur anywhere else, but
always in the neighbourhood of a Closterium containing these
organisms ; and where they nearly all, or a few only, still
contained their endochrome, these abounded close by in the
relative numbers to be expected. Admitting them to be
such, it may appear questionable whether this growth be
connected with the development of the Closterium itself, or
whether it be a true parasite. I am disposed myself to think
the latter. But, be this as it may, I need hardly insist on
the essential distinctness between the phenomenon depicted
in Fig. 5, and the condition of Docidium shown in Figs. 1 to 4.
It may be well to say that the three ovate ciliated bodies on
the Plate near Fig. 4 represent the zoospores appertaining
to it, whereas all the other scattered orbicular bodies be-
long to Fig. 5. Notwithstanding any description I can
offer is so very incomplete, I venture to think the draw-
ing itself (a faithful copy from nature) may prove interesting.
It seems highly probable that Ehrenberg’s genus Polysolenia,
included by him and by Kiitzing in Desmidiace (vide Kiitzing,
“Species Algarum”) must have been truly a Closterium
(probably C. didymotocum) so attacked. I draw attention
here to this very interesting growth, in order to guard against
any possibility of its bemg thought the remarkable condition
of Docidium is identical with it, or that | may have myself
in any way mistaken the one for the other.

Here, however, my observations conclude, for I am totally
unaware of the after development of the motile gonidia, the
original formation and emission of which I have described.
It may be urged that I cannot prove these bodies to be truly
zoospores, because I cannot prove they grow into young
Docidia, as can more or less readily be done according to the
species im various other Algz, in which the growth of the
zoospores into young plants similar to the parent is witnessed
with not great difficulty. Possibly the bodies I have described
may be but equivalent to those described in somealge as micro-
gonidia by theGerman writers ; but I cannot for the present see
the probability of this assumption, and imagine they are more
likely to be true motile buds, 7. e. zoospores. It will be borne

234 ARCHER, ON DESMIDIACE.

in mind that the true generative process in Docidium Ehren-
bergii, like all other undoubted Desmidians, is by conjugation.

Assuming that Iam mnght, the bearing of the fact would
not be in the least to affect the acknowledged affinities of this
family with their more immediate allies, the Zygnemacez, or
with the Diatomacez ; for in the former, in Spirogyra and
Mougeotia, ciliated motile bodies, probably zoospores have
been noticed; while in the Diatomacez, although such a
phenomenon had been previously suspected, I need only
advert to the researches of the Rev. E. O’Meara (loc. cit.),
which render it equally probable, if not decided, that such a
mode of propagation prevails also in that family.

Such, then, is an account, deficient, as I regret it is, in
many points, of what I cannot but look upon, so far as I can
make out, as a new and unrecorded phase in the lfe-history
of this beautiful and interesting family, the Desmidiacez,—a
life-history still obscure in many of its details, but yet one
which I aver will not yield in interest to any other portion in
the wide domain of our comprehensive science of Natural
History, and one also on which I shall deem myself very
fortunate and very happy should these humble observations
of mine, here recorded, ever be found eventually to shed even
a dim and solitary ray of light in its elucidation.

Further Notes on Abnormal Growth in the Desmidiacee.

In a former paper read to this Society (vide ‘Nat. Hist.
Reyv.,’ vol. vi, page 469), I drew attention to an abnormal
mode of growth affecting several species of Desmidiacez, and
I may add that I have since noticed similar cases in two or
three other species. This consisted in there being produced
between the old segments, not a pair of new ones eventually
to become symmetrical with the old, but an irregular, more
or less unsymmetrical inflated expansion, forming with the
old segments but one uninterrupted cavity ; and this kind of
monstrosity I endeavoured to show might probably be
primarily due to the omission of the formation of a septum as
a preliminary to ordinary vegetative growth. In Pl. XI,
Fig. 7, I bring forward what seems to be a further extension
of the same identical condition of Arthrodesmus Incus, as that
figured in Pl. xxxiii, Fig. 11, 2. c. In the case last in-
dicated, as in the others, there must exist a suture between
the older segments and the intermediate abnormal growth—
that is, the latter has become interposed between the older
segments by their separation at the original suture.

ARCHER, ON DESMIDIACES. 235

Now Fig. 7 of the present Plate seems to indicate that the
vegetative energy is not necessarily arrested ; for between the
central growth (of the first case in A. Incus figured), and each
of the original segments, a new expansion has been formed—
the whole, that is, the older segments and the now ¢hree in-
tervening portions (the middle one being the older) forming
still one uninterrupted cavity, and filled with endochrome
throughout. The entire structure, under a low power, might
be mistaken for a Scenodesmus; but, when sufficiently
magnified, its real nature is quite apparent. The specimen
(Fig. 7) occurred amongst several others in the condition
figured with my former paper (Fig. 11), both mixed with
multitudes in the normal state, some in the dividing con-
dition. There does not seem any readily assignable limit to
the extent to which this monstrosity might be carried ; yet,
even supposing it had attamed some considerable length, and
that the extraordinary structure should survive its own
fragility, a time must come, I conceive, as in normal indivi-
duals, when the vegetative impetus would be spent, and when,
therefore, further increase by mere self-division (in this case,
however, abnormally and abortively undertaken) would subside.

Fig. 6 represents a remarkable mycelioid growth occurring
within a Closterium lunula, noticed in the paper alluded to,
read to the Society (page 472, /. c), remarkable on account of
the impossibility, except on Pringsheim’s theory in regard to
Pythium (vide preceding Paper), of accounting for the origin
of such a curious internal parasite.

Description of a New Species of Cosmarium, and of a New
Species of Xanthidium.

Family —DESMIDIACE.
Genus.—Cosmarium (Corda).
Cosmarium Portianum (sp. nov.).

Specific characters: Frond deeply constricted ; segments,
in front view, broadly elliptic, rough with minute, scattered,
pearly granules, constriction deep, wide, isthmus forming a
short neck ; end-view elliptic.

Locality: Pools, Dublin and Wicklow Mountains ; not
uncommon.

General description: Frond minute, compressed, in front

236 ARCHER, ON DESMIDIACE.

view about one third longer than broad, rough all over with
minute, scattered, somewhat depressed pearly granules, which
give a minutely denticulate appearance to the margin, deeply
constricted at the middle, the constriction forming a gradually
widening notch at each side, rounded below; segments, in
front view, broadly elliptic, in side view, suborbicular, con-
nected by a rather narrow isthmus, forming a short neck;
end view, broadly elliptic. (Sporangium, after a figure by
Professor De Bary of an undescribed species supposed to be
the present : orbicular, beset with somewhat elongate, conical,
blunt spines.)

Measurements: Length of frond, 4,th; breadth of frond,
gioth of an inch.

Piatt XI.—Fig. 8, front view; Fig. 9, end view.

Affinities: The granulated surface and compressed frond in
this species forbid its being mistaken for any of those in
which the surface is smooth, or the end view circular. Of
those species with which it agrees in the characters first m-
dicated, it is about the most minute, and I believe it is other-
wise amply distinguished from them by its elliptic segments
in front view. It perhaps most approaches C. margaritiferum
(Menegh.), but, besides its smaller size, it differs from that
species and C. datum (Bréb.) in not having reniform or semi-
orbicular segments, as well as in the constriction being not a
linear, but a wide notch. The same characters distinguish
it from C. Brébissonii (Menegh.), as well as the pearly
granules being minute and closely scattered, not rather
widely distributed and conic. From C. tetraophthalmum
(Bréb.) it also differs in the same characters, as well as in
that of the superficial granules, which in that species are
broad, giving the margin a somewhat undulate or crenate,
rather than a minutely denticulate, appearance. From C.
Broomei (Thwaites) and C. biretum (Bréb.) it differs, besides
other characters, in its elliptic, not quadrilateral or angular,
segments. From C. premorsum (Bréb.), C. notabile (Bréb.),
and C. Botrytis (Menegh.), as well as C. protractum (Nag.),
C. gemmiferum (Bréb.), and C. Turpinii (Bréb.), it differs in
having rounded, not truncate, ends, and from all the species
just named in the central constriction, not forming a linear
but a wide notch.

It is at once distinguished from C. orbiculatum (Ralfs), with
which it agrees in the constriction not forming a linear notch,
by the segments being elliptic, not spherical, and the end
view not circular; besides the pearly granules being minute

ARCHER, ON DESMIDIACES. 237

and depressed, not elevated and conic. It is true that Pro-
fessor de Bary (‘ Untersuchungen iiber die familie der Con-
jugaten,’ Taf. VI, 49 @ 8) alludes to a Cosmarium called by
him Cosmarium orbiculatum (Ralfs), which, I apprehend, is
actually the species now described, but, with great deference,
I think he is wrong; this form differs quite from C. orbicu-
latum (Ralfs), as much, indeed, as C. bioculatum (Bréb.) does
from C. moniliforme (Ralfs). Assuming that I am right in
the conjecture that the present species is identical with that
alluded to by De Bary under the name of C. orbiculatum
(Ralfs), the sporangium has been provisionally described in
the foregoing specific characters, taken from the figure given
by that observer, although I have not myself met it con-
jugated.

As to other granulate species, so far as I am aware, it needs
only to contrast this form with C. pluviale (Bréb.), with
which it agrees in being compressed, and in the constriction
not forming a linear notch, but it differs in the form of the
segments, which, in the species just named, are nearly as
broad as long, sub-ovate or sub-orbicular, ends rotundato-
truncate; whereas, in the species in question, the segments
are broader than long, elliptic, and ends rounded, the con-
striction forming a short neck. Of the smooth species, it
most nearly approaches C. dioculatum (Bréb.) in form, but
the granulate surface of the present species at once dis-
tinguishes it. The same circumstance, as well as the want of
the solitary superficial projection on each front surface of the
segments, separate it from C. phaseolus (Bréb.).

I am not aware of any other species with which it seems at
all requisite to compare the present form, nor does there in-
deed appear to me any danger, with proper attention, of con-
founding it with any of those I have mentioned. This has
occurred to me for three or four successive years, and I have
no doubt of its distinctness. I have several times been asked
the name of this species: to afford a more satisfactory answer
than hitherto, the next time the question may be put to me,
I have no hesitation in assigning one to this pretty little
species.

On a former occasion (‘ Nat. Hist. Rev.,’ vol. v, p. 251) I
had the pleasure to name a species, for the ample reasons
there given, after my friend, George Porte, Esq. I was not
then aware that Professor De Bary, in Germany, had antici-
pated me; consequently, my name for the species alluded to
fell to the ground, and with it much of the compliment I had
intended. ‘To restore the latter, I trust the present attempt
may be more successful.

238 ARCHER, ON DESMIDIACEX.

Genus—Xantuipium (Hhr.).
Xanthidium Smithii (sp. nov.).

Specific characters: Segments trapezoid; spines minute,
straight, acute, marginal, in four pairs; central projections
‘minute, rounded, tubercle-like.

Locality : Numerous specimens were met with by me on a
slide marked “‘ Wareham, 1849, W.S.,” kindly lent to me by
Professor Harvey.

General Description: Frond minute, in front view about
as long as, or very slightly longer than broad; constriction,
a deep, gradually widening notch; segments about twice as
broad as long, trapezoid, lower margin somewhat convex,
sides narrowing upwards and straight, ends broad and straight;
spines short, minute, straight, acute, marginal, geminate, a
pair placed on each of the four angles; in side view, segments
about as broad as long, with rounded sides, ends truncate,
each upper angle furnished with a minute spine, beneath each
of which, about halfway down the segment, there occurs
another spine, all the spines divergent; end view sub-elliptic
or broadly fusiform, ends truncato-convex, furnished with
three spines, the spines projecting, div ergent, none at the
sides; the central projection from each front surface a
minute, rounded, smooth tubercle, apparent always in end
view ; in the side view the tubercles are sometimes concealed
by the projecting divergent central spines, while in the front
view they are hidden by the contained endochrome. Spo-
rangium unknown.

Measurements: Length of frond, +3;5; breadth, 334, of
an inch.

Pirate XI.—Fig. 10, front view; Fig. 11, side view; Fig. 12,
end view.

Affinities: This interesting little species seems to be allied
on the one hand to Xanthidium fasciculatum (Ehr.), and on
the other to Arthrodesmus octocornis (Khr., Hass., Bréb.)=
Xanthidium octocorne (Ralfs), var. (3, but is perfectly and, I
believe, unmistakably distinct from either. With the former
it agrees in the spines being subulate, marginal, and in pairs,
and in the central projection being not granulate; but it
differs in its far more minute size, and in its segments being
four-sided, not reniform or sub-hexagonal, and in its spines
being short, and minute and straight, not elongate and
usually curved, and in its constriction not forming a linear
notch. With the other species named (var. (3) this form

HICKS, ON GONIDIA OF LICHENS. 239

agrees in its trapezoid segments, and in the number and dis-
position of its spies, but differs in possessing the central
frontal projections, which are absent in the species alluded to,
and which circumstance, I think, should place it out of the
genus Xanthidium. The form now under consideration also
differs from that alluded to im having its margins straight,
not concave; in its spines being minute, not elongate; in
the segments, in side view, which is less compressed, being
sub-orbicular, not elliptic; im the ends bemg truncate, not
rounded ; and in the extremities in the end view being blunt,
not rounded. Notwithstanding, therefore, considerable simi-
larity in the general outline between the present species and
Arthrodesmus octocornis, var. [3, 1 cannot suppose they can
be identical. The latter I have not myself met with in this
country, but var. a is not uncommon. However, | prefer to
follow Brébisson, and to place both those forms in the genus
Arthrodesmus, though, perhaps, Jenner’s suggestion to form
a new genus for them, including, of course, Arthrodesmus
bifidus (Bréb.), would, after all, be the better course. Certain
it is that the plant now described is an unquestionable
Xanthidium.

I imagine the initials on the slide above alluded to must be
those of the late Professor William Smith; it is, however, in
any case by no means an inappropriate, though but a small
and very inadequate, mark of respect to dedicate this species,
which I believe to be very distinct, to his memory.

Contrisutions to the knowledge of the DEvELOPMENT of the
Gonrp1A of LicuEns, in relation to the UNICELLULAR ALG&,
&c. By J. Braxton Hicks, M.D. Lond., F.L.S., &c.

Fascicutvus 1.

Ir needs no remarks of mine to pomt out the extreme
ambiguity which exists in regard to the arrangement of both
the species and genera of the unicellular algze and their kin-
dred organisms. Perplexing to the last degree to the older
student, to the novice they are bewildering, and highly un-
satisfactory to all who, allured by their simplicity of struc-
ture, have been desirous of studying Nature on her protophytic
threshold.

However, within the last few years an opinion, based on

240 HICKS, ON GONIDIA OF LICHENS.

some valuable observations,* has sprung up—that many
organisms of the class alluded to are but a condition of the
growth of the gonidia of lichens.

To add new facts to those already published, tending in
the same direction, will be the endeavour of the following
contributions, and which, it is confidently hoped, will throw
additional light on this confessedly difficult subject.

And it may be well at the commencement to remark that
the gonidia of lichens have extraordinary powers of dissemi-
nation, far beyond what is generally recognised. From a series
of observations, extending now over many years, in which they
were never absent, I found that they may be collected in
comparatively great numbers from snow and rain, par-
ticularly the former, and especially in windy weather. The
quantity of gonidia, frequently with attached fragments of
lichens, entangled and brought down by the snow, generally
considerably exceeds that of any other organic molecules.

Experiments upon this point may be easily made by placing
a clean sheet of glass in the open air during a fall of snow.
When a sufficient quantity has fallen, it should be melted,
and the snow-water allowed to run into a tube; the super-
natant fluid bemg poured off after the foreign matter has
subsided, I have noticed sometimes that the discoloration of
the water is in a great measure dependent on the gonidia of
lichens. These I have kept in the water for some months,
and have scen them passing through the same varieties of
segmentation to be described below as occurring in the
gonidia of lichens and in ‘ Chlorococcus.”” Hence it will be
seen that every surface upon which snow or rain can fall
must have a number of these gonidia deposited upon it during
the year. In the course of the following communication it
will be seen that these organisms have the property of in-
creasing to an unlimited extent by subdivision, and thus will
be explained how enormous surfaces are covered by the so-
called ‘‘ Chlorococcus.”

Now, although the gonidia of the various lichens are
wafted by air-currents hither and thither, doubtless to very
distant points of the globe, yet we may for the same reason
expect the unicellular algze and their allies, if really derived
from them, would, in any given district, vary < according to
the species of lichens prevalent in that district ; and “this
I have found, so far as my observations have extended, to
be the case ; for although the gonidia of many lichens are
scarcely to be distinguished from each other, yet there are,

* See ‘Botanische Zeitung,’ 5th January, 1855, I. H. Ibid., 1855,
Herm. Itzigsohn. ‘Microscop. Dict.,’ art. ‘ Palmellaces.”

HICKS, ON GONIDIA OF LICHENS. 241

in many, constant minute differences, visible to a practised
eye, while in some there are essential variations during their
growth, which will be noticed hereafter.

After these remarks I wiil pass to the consideration of that
unicellular plant, commonly called “ Chlorococcus,” which
covers with a green coating, walls, trees, palings and mdeed
any exposed body rough enough to give attachment to it.

It is, in its mature, quiescent state, a round, globular cell
(fig. 1, a, a), consisting of a cell-wall, with green cell-contents,
having a nucleus in its centre. It is shown highly magnified
at fig. 3. These cells may remain in a dormant condition for a
considerable time during cold weather, but upon the return
of warmth and moisture they begin to increase in numbers,
by a process of subdivision which varies in the different
cells.

Sometimes the mass of contents divides into from two to
eight or more portions, which soon assume a round form, and
burst the parent cell-wall open; or the septa radiate from the
centre; these secondary cells soon begin to divide by binary
and quaternary division, and this process may go on for a
very long period, even for years, without much variation.
The size of these divisions varies according to the rapidity
with which the process of segmentation exceeds that of
individual cell-growth (Pl. X, figs. 1, 2). Ultimately, how-
ever, they all assume the form and size of the parent round,
nucleated cell.

Now, the gonidia of many of the lichens are precisely
similar, both in the mature, quiet state, as also in the active
process of multiplication, and are of the same size. This is
well seen in making a section of the thallus of any ordinary
lichen about to undergo what is called ‘“soridiferous de-
generation—for instance, of Parmelia parietina. The gonidia,
increasing beneath the cortical layer by subdivision, at first
elevate in parts the layer above it, till at length they burst
through, and then at first appear of a green colour, continuing
the process of subdivision in a manner indistinguishable in
every respect from the “ Chlorococcus”’ before described.
For this reason it has been suspected by some recent inves-
tigators that the latter is possibly derived from the gonidium
of the lichens.

The additional facts I shall brmg forward will, I conceive,
set the question affirmatively at rest.

It will, therefore, be necessary to watch the true gonidium
a stage further, while still resting on the thallus through
which it has burst. After the process of segmentation has
been repeated an uncertaim number of times, and the divisions

242 HICKS, ON GONIDIA OF LICHENS.

have again become full-sized and globular, it begins to make
the first step towards the formation of the felted fibres of its
parent, and it will be observed that a small, colourless, tubular
projection appears at one spot on the surface of the cell-wall
(fig. 2 a), which, increasing in length becomes a tubular
fibre, which, whilst adhering closely to the exterior of the
cell, and articulated and branching (fig. 2, 5, 4, 6), at last
completely encloses it by its ramifications, which vary in
colour. In the case of Parmelia parietina they are yellow,
and the round mass, opaque by transmitted light, and rough
on its outside in consequence of the branches of the fibres
not closely adhering by their ends, is denominated a
“soridium.” This gives the powdery appearance to the
surface of the lichen upon which it rests, and has a consider-
able influence on the general colour of the plant, which thus
depends on the amount and colour of these enclosing fibres.

The soridium may remain in this stage for an indefinite period
—for months, and, I suspect, even for years—in which event
the case produced by the branching, adherig fibres becomes
thickened and denser, as shown at fig. 9. This is generally
more apparent during the colder months, and is probably a
means of protection.

When segmentation commenceswithin this soridium, it often
results in a very large number of subdivisions, as at fig. 10, a,
and the fibres, passing inwards between the segments, separate
them, while the whole ball enlarges, so as to produce the first
commencement of a thallus. This point is of importance, as
will be remarked upon when we come to speak of the corres-
ponding stage in the “soridium” of Cladonia. But segmen-
tation of the enclosed gonidium may proceed simultaneously
with the fibre-growth, in which case the soridia assume the
appearance shown at figs. 4and5. Frequently the subdivisions
become oval and small, undergoing binary segmentation.
Fig. 6 represents an instance of this, in which the parent
cell-wall is still seen partly dissolved. Fig. 8, a, also shows
this form. In others they are globular from the commence-
ment, and simply increase in size, as at figs. 4, 5, 10, 4, d, till
they are as large as the parent cell.

The contents of one of these broken soridia is shown at
fig. 8, with fibres branching among the segments.

Precisely the same changes take place in the so-called
* Chlorococcus.”’ As 1 said before, the multiplication by
division may proceed during an indefinite period; however,
circumstances favouring the tendency to form the fibre com-
mences, anda “ soridium” is the result. To describe these
changes would be but to repeat the above remarks on the

HICKS, ON GONIDIA OF LICHENS. 243

process in the undoubted gonidium of the lichen. If a
portion of the bark of a tree on which the Chlorococcus is
growing be placed under glass, so as to keep it in a
moderately moist atmosphere, the phenomenon may be
observed in all its changes. It may also be traced perfectly
in nature, and may be recognised by lighter-coloured patches,
appearing where “ Chlorococcus” has been growing. That
the change of colour is caused by the growth of the fibres
may readily be seen on microscopical examination; and this
point is instructive, because it will be found that the colour
varies notably according to the lichen prevalent in its neigh-
bourhood. Where the yellow Parmelia is found, the
*Chlorococcus ” will assume a yellow tinge in its soridial
stage. Viewed by transmitted light, they are also opaque
balls, with irregular outline (fig. 7).

But it must be clearly understood that every Chlorococcus
does not follow exactly this course, for I shall show marked
exceptions; but it obtains with the generality; and it is a
remarkable fact, that when ‘“ Chlorococcus” does vary, it is
. In the neighbourhood of those lichens whose gonidia also
vary, and in precisely the same manner.

That this “ Chlorococcus” stage does continue for a long
period without showing any disposition to form soridia, con-
stantly multiplying till large surfaces are covered, and to some
depth, may be plaimly observed; and this, taken with what
I have remarked before, will explain its almost universal
presence. This condition seems to be favoured by cool, moist
weather. The soridia also remain dormant for a very long
time, and do not develop into ¢thalli unless in a favorable
situation; in some cases, I think, for years. It will be
easily perceived that the soridium contains all the elements
of a thallus in miniature ; in fact, a thallus does frequently
arise from one alone, yet, generally, the fibres of neigh-
bourimg soridia interlace, and thus a thallus is matured
more rapidly. This is one of the causes of the variation of
appearance so common in many species of lichens, and is
more readily seen towards the centre of the parent thallus.
When the gonidia remain attached to the parent thallus the
circumstances are, of course, generally very favorable, and
then they develop into secondary thalli, attached more or less
to the older one, which, in many instances, decays be-
neath them. This process being continued year after year,
gives an apparent thickness and spongy appearance to the
lichen, and is the principal cause of the various modifi-
cations in the external aspect of the lichens which caused
them formerly to be misclassified.

244 ARNOTT, ON CYCLOTELLA.

Summary.—\ think, then, from the above remarks, that
there can be no doubt but that what has been called
“ Chlorococcus”? is nothing more than the gonidia of some
lichens, which, having been conveyed by the movements of the
atmosphere, had been deposited on a favorable surface, where
they soon begin to increase by various modes of segmen-
tation, which continue for an unlimited period. But under
suitable conditions, chiefly drought and warmth, the gonidium
throws out from its external envelope a small fibre, which,
adhering and branching, ultimately encases it and forms a
“ soridium.” At this stage gonidium may continue also for
an indefinite period in a dormant condition, but, circum-
stances favoring, segmentation of the gonidium goes on
within the soridium, while the branches of the fibre penetrate
within the divisions, till at last a young thallus is formed.
But a check may occur during any of these stages, and yet
vitality be prolonged for a period of months and even years.

Of this, I believe, any one may satisfy himself if he will
be careful to watch an old wall or tree, and check his
observation by the microscope from time to time. In every -
particular, the whole of these stages are passed through by
those gonidia whose pedigree is known, which, having burst
through the cortical layers of the lichen-thallus, still re-
main attached to its surface.

There are two other points which, although they require
more observations to give any certain value to them, it will
be as well to mention here :

The first is the occurrence among the fibres of dilatations
which contain a number of small, actively moving bodies, of a
reddish-brown colour (as at fig. 11, a, a). They apparently
have a motion different from the ordinary molecular move-
ment.

The other is, that there are to be found among the crushed
soridia some small, moving, green cells, like minute z00-

DID

spores, but I cannot satisfy myself as to their origin.

On CYCLOTELLA.
By G. A. Watxrr-Arnort, LL.D.

My object is not to give here a monograph of the genus
Cyclotella, but to endeavour to clear up the synonyms of our
British species, which to me appear to be im a little con-
fusion.

ARNOTT, ON CYCLOTELLA. 245

C. Dallasiana was described by the late Professor Smith
from a single specimen; he characterises it by the disc
cellular; his slide, now in the British Museum, has been
carefully examined by Mr. Roper, and the valve identified by
him with specimens he has obtained from the Thames.
The dise or portion of the valve within the striated margin is
not areolate, as may be inferred from the term “cellular,”
but merely minutely bullate or puckered, or asif blistered, on
account of numerous little elevations and depressions ; per-
haps bullate-rugose is the most expressive mode of descrip-
tion.

What Smith had seen is the large form, and probably the
sporangial state of the diatom; but there is another form of
it, much smaller (with occasionally the large one sparingly
mixed), which I have long ago had sent me by Mr. J. T.
Norman, No. 178, City Road, London. ‘This small one
appears to be not unfrequent about Woolwich, although it
has not.as yet been obtained in a sufficiently pure state to
afford good slides. If attention be not paid to the bullate,
but otherwise flat, and not projecting or undulate, smooth
centre, this may be readily mistaken for a state of C. Kutz-
ingiana, Sm.; and I have no doubt whatever that it forms
C. Kutzingiana 3 of Smith, as far as the British localities
are concerned, although quite distinct from the synonyms
adduced. Like C. Kutzingiana, it only occurs in brackish
water.

Smith states that C. Kutzingiana is met with in fresh and
brackish water ; I have never seen the true species from fresh
water, and believe that he added this kind of locality from
erroneously supposing that C. rectangula of De Brébisson, or
C. operculata [3 of Kiitzing, which is a fresh-water species,
was the same as his C. Kutzingiana [2. Specimens, however,
of C. rectangula, De Bréb., from De Brébisson himself, and a
portion of the only gathering he ever made of it (near Paris),
prove that diatom to be no way distinct from C. Meneghiniana
of Kiitzing, a species allied to C. Kutzingiana, and having the
same coarse, marginal striz; but differing by the flat, not undu-
late, ends, and by its fresh-water locality.

What is called C. operculata presents two forms, both
figured by Ktitzing. One has the centre of the valve smooth
and projecting obliquely (as in C. Kutzingiana), forming, as it
were, a sort of operculum or convex lid to the valve, the
projecting portion of the one frustule corresponding to that
of the contiguous one which does not project, thus presenting
an undulate appearance on the front view ; to this the name
operculata properly belongs. The other has a flat (not pro-

246 ARNOTT, ON CYCLOTELLA.

jecting) disc, but the disc is marked by radiating dots or
lines. Smith, in his ‘ Synopsis,’ had both in view : the first, or
true C. operculata, he has described with sufficient precision,
although, in place of being concave or depressed in the centre,
as he says, I consider it to be convex or elevated; the second
form is the one which he has figured in Tab. v, fig. 48, and is
also that which he distributed in his Lough Neagh slides; it
occurs near Ulverstone and Hull, and is probably not un-
common.

Besides the above, Kiitzing has a species from the Lunne-
burg deposit, which he calls C. minutula; this occurs in many
deposits in this country. It is this which Smith obtained from
the Lough Mourne deposit, but which he has unfortunately
referred to C. antigua, a species which does not occur in any
of the Irish deposits which I have examined. The largest and
finest specimens of it which I have seen are from the exten-
sive deposit near Toomebridge, between Lough Neagh and
Lough Beg, and that from Loch Leven, Kinross-shire, in
both of which it is mixed with C. Rotula, Sm.

On carefully comparing the C. minutula from deposits with
the second form of C. operculata, I have little doubt of their
identity ; both have got the same kind of centre to the disc.
It seems to have a double coat of silex near the margin, or at
least two surfaces differently marked ; the upper one presents
a series of short, close, marginal striz, resembling a narrow,
striate, convex ring, surrounding the flat disc ; the under one
is flat, broad, and conspicuously striate from the margin to the
central portion or disc. Such are the appearances presented
when both states are perfect; but when the recent form
(usually confounded with C. operculata) becomes abraded or
much macerated, it seems to pass into the other ; my impres-
sion, therefore, is that the one got in deposits (or C. minutula
true) assumes its distinctive appearance solely by long expo-
sure and maceration, and that it and the recent one (Smith’s
tab. v, fig. 48) ought to be united. The name of minutula
is certainly objectionable, as the specimens, even when in
deposits, are often so large that they might be mistaken for
a small form of C. Rotula; but changes of specific names
lead to confusion when not transferred to another genus, and
it is therefore preferable to retain that given by Kiitzing.

These five may be comparatively distinguished from each
other thus :

1. C. Dallasiana; ends of frustule flat; centre of valve
bullate-rugose, marginal striz coarse.

2. C. Meneghiniana; ends of frustule flat; centre of valve
neither striate nor bullate ; marginal striz coarse.

ARNOTT, ON CYCLOTELLA. 247

3. C. Kutzingiana; ends of frustule undulate ; centre of
valve convex, but neither striate nor bullate; marginal strice
long, coarse.

4. C. operculata; ends of frustule undulate, centre of
valve convex, but neither striate nor bullate; striz short,
close.

5. C. minutula ; ends of frustule flat; centre of valve with
radiating dots or striz.

To C. Dallasiana 1 refer C. radiata of Brightwell. I
possess what I consider to be C. Meneghiniana from a stream
that empties itself into Bidston Marsh, Cheshire, where it
was collected in August, 1858, by Mr. T. Comber; but
it is not noticed in his “ Catalogue of Liverpool Diatoms,”
‘Mic. Journ.,’ viii, p. 113), unless it be what he calls
C. Kutzingiana, 33.* Mr. G. Norman, of Hull, has also found
it in the pond of the botanic garden there, and in some other
places about Hull; but in all these localities it is very sparse,
and much mixed with other diatoms. I have not seen a
good frustule with the front view from England, but I
do not think that any doubt can be entertained about the
species.

C. Rotula, Sm., from deposits, sometimes approaches
closely to C. minutula, but has distinctly moniliform strie,
and when recent has a series of small, broad-topped, nail-
like, spinous processes close to the margin, and perpendi-
cular to the surface of the valve; these are easily broken
off, and this affords one of the many arguments against
drawing up specific characters from specimens obtained from
deposits ; the latter may, by ocular comparison, and even
by written characters, be frequently correctly referred to
the recent form, but recent ones can rarely be satisfactorily
determined from descriptions made only from the abraded
state. C. Rotula, Sm., is C. Rotula, Kitz. (‘ Bac.,’ tab. ii,
fig. 14) ; but as Ehrenberg had already described a Discoplea
Rotula, and also a Disc. Rota, both from the South Seas,
which Kiitzing afterwards supposed to be also species of
Cyclotella, he, in his Species Algarum, changed his former
appellation from C. Rotula to C. Astrea. This change was
uncalled for, as the first diatom described under the com-
bined names of Cyclotella Rotula is that of Kiitzig, and
that name has been adopted by Smith; to it the name
Rotula ought still to be attached, unless we take into con-

* Catalogues of names are of very little use when not accompanied with
diagnostical remarks taken from the specimens collected ; for if the writer
makes a mistake, as all may readily do in microscopical objects, there is no
way of ascertaining what was intended.

VOL. VIIL. U

248 HENDRY, ON THE SACCHARO-POLARISCOPDE.

sideration that Kiitzing himself made the alteration before
Smith published his ‘ Synopsis,’ although Smith was unaware
of it. To this species must be referred Stephanodiscus
Niagare of Ehrenberg, and perhaps also his 8. Egyptiacus.

The SAcCHARO-POLARISCOPE.

By Witu1am Henpry, Esq., Surgeon, Hull.

THE instruments usually figured as employed in the po-
larization of saccharine solutions are, for the most part, of
costly and complex character. Having experienced a
little curiosity in the subject, mduced through a desire
to investigate diabetic urime microscopically, I had occa-
sion to refer to an article contaimed in ‘ Morfit’s Chemical
Manipulations ;? and, in pursuance of the methods therein
described of Professor M‘Culloch, Soleil, Clerget, and others,

I have been enabled to fit up

an apparatus which will be found

ea¢ efficient, convenient, and inex-

pensive, whereby the beauteous

2\ikxo phenomena of right- and left-

handed polarization indicative

of cane or grape sugar may be

readily exhibited, or the ares of

prismatic coloration measured,
as occasion may require.

I am indebted to Mr. Row-
ney, of Hull, for the accom-
panying drawing, representing
the arrangement of the appa-
ratus.

First, procure a gutta-percha
tube a, of a calibre to receive
the ordinary B eye-piece (which
might be in demand for other
uses), and about 10 inches in
length; fix upon its lower or
distal extremity a disc of clear
glass between two layers of
gutta percha cemented by heat, and perforated to transmit
the polarized beam of light, the polarizer 8, as usual, bemg

i ru Tits
\, StU SS
im \i'; =
Wie

HENDRY, ON THE SACCHARO-POLARISCOPE. 249

fixed below the stage. The tube thus prepared is to be
substituted for the body of the microscope, and retained
by one or more elastic bands c to the stand-frame, and
placed in a vertical position for use, resting close upon the
stage.

Secondly, fit the top of the gutta-percha tube with
a turned wood stopple (not seen in the drawing), 1 inch in
depth, three fourths of which should enter the tube mode-
rately tight, just so as not to rotate, and one quarter should
constitute a collar or rest, say of 3 inches diameter, over-
hanging the tube, for convenience of handling on removal,
&e., and let this stopple be perforated in the direction of
its axis, with a -°,th- or j/,th-inch aperture; then fix also
permanently upon its upper surface a compass card p,
marked in degrees of a circle, and with a corresponding per-
foration.

Now prepare another stopple, £, of 1 inch in depth, and
1+ inch broad at the bottom, tapering to 14th inch above,
and perforated as before ; let this be mounted upon the first
stopple, interposing the compass-card and a circular slip of
card or two to facilitate rotation, having a needle, r, inserted
laterally as an indicator to denote the arc of polarization. (The
two stopples may be turned out in one, and afterwards cut
across).

A piece of brass tubing, such asis used for jointing fishing-
rods, of about 2 inches in length, should be fitted firmly m
the perforation of the upper stopple, but made to rotate
freely within that of the larger or

under stopple, thus allowmg the indi- SINCH
cator to be turned freely, and without * =
disturbance to the compass-card. The i

analyser eG, as usually employed above
the objective in ordinary polarization, is now placed within
the upper part of the brass tubing, projecting half an inch
above, and lightly packed with gutta percha, so as to have an
independent rotation, to adjust, fix, or remove at pleasure.
A slip of glass, n, of about 1 inch in length, may be inserted
in the body, having a gauge-mark drawn across it at 4
distance of 7,8,ths inches from the bottom of the tube (inner
surface), to ensure a given depth of the solution or syrup em-
ployed. The several parts being now duly centred, the appa-
ratus is complete for ordinary observation ; but for com-
mercial or extended scientific research, a thermometer and
hydrometer will be required, with tables of reference.

A syrup, prepared by boiling three or four ounces of loaf
sugar In acorresponding quantity of water and filtered, while

250 HUXLEY, ON THE MOUTH OF THE SCORPION.

hot, through blotting-paper, may be poured when cold into the
tube on removal of the stopples, which are to be replaced ; and
when the upper piece © is rotated from left to right, a
resplendent coloration is exhibited, following the right-handed
prismatic series, in the order of violet, red, orange, yellow,
green, blue, indigo, indicative of cane sugar. Then, for the
development of the order of coloration indicative of grape or
uncrystallizable sugar, proceed as follows :—empty the syrup
from the tube into a phial, add two or three drachms of
hydrochloric acid (one drachm of acid to nine drachms of
syrup), and place aside for twelve hours, or thoughout the
night. In the morning replace the acidified solution into the
tube a, as before, and note the order of coloration, which,
the cane, now being converted into grape-sugar, will, upon
the rotation of the analyser or upper stopple © in the same
direction as before (from left to right), present the reverse
series of colours, or violet, indigo, blue, green, &c., &e. Of
course, for practical quantitative or per-centage estimation,
regard must be had to exact measures, to which we do not
now refer.

The B eye-piece, selected as a measure for the calibre of
the tube or body a, having been removed for the adaptation
of the stopples, may at any time be replaced, and, instead
of the Nicol’s prism, be surmounted with a prism of uncut
Iceland spar, or rather by a special double-image prism,
for the magnified exhibition of the phenomena of simul-
taneous complementary coloration, the syrup being used as
before.

Sufficient may have already been advanced to awaken
interest and to induce investigation of the brilliant phenomena
of saccharine polarization; and at the same time a clearer con-
ception will have been obtained of the manipulation required
for the purpose of subjecting diabetic urine to the polariscope,
involving a process probably a little more complex than is
usually considered of concentration, clarification, &c.

On the Sructure of the Mourn and Puarynx of the
Scorpion. By Tuomas Henry Huxtey, F.R.S., Pro-
fessor of Natural History, Government School of Mines.

Axtnoucn the scorpion has been made the subject of
repeated investigations by some of the best minute anatomists

HUXLEY, ON THE MOUTH OF THE SCORPION. 251

of past and present times, it is a remarkable circumstance
that no exact account of the structure of the commence-
ment of its alimentary canal is to be met with, at least so
far as my knowledge extends. Meckel (‘Beitrage zur
Vergleichenden Anatomie,’ Bandi, Heft 2, 1809), as might
be expected from the fact that his dissections were per-
formed without the aid of even a magnifier (page 106), takes
no particular notice of the small and delicate parts in question.
Treviranus (‘ Bau der Arachniden,’ 1812) is equally silent as to
this important portion of the economy of the scorpion; and even
the accurate Johannes Miiller, in the essay entitled ‘“ Beitrage
zur Anatomie des Scorpions” (Meckel’s ‘ Archiv.,’ 1828),
which threw so much new light upon the organization of this
animal, although he saw more than either his predecessors
or his successors have done, did not probe the matter to
the bottom. In describing the alimentary eanal, he merely
says :—‘ The pharynx which arises in front of the brain,
upon a particular, strongly excavated, portion of the skeleton,
is much wider than the rest of the intestine, and resembles a
vesicle. The cesophagus is very delicate where it proceeds from
this vesicle, rises between the very stout nerves for the chele,
above the brain (which lies behind the pharynx), and passes
over the saddle-shaped upper excavation of the internal
thoracic skeleton, whilst the spinal cord and the posterior
cerebral nerves pass through the opening of the same
skeleton.”

Even the elaborate and beautifully illustrated memoir on
the organization of Scorpio occitanus, published by M.
Blanchard, a couple of years ago,* does not furnish the in-
quirer with either definite or accurate information on this
point. At page 19, I find under the head of “ mouth :”

“Tn the scorpion there exists only a single buccal piece properly so called ;
it is inserted in the median line above (au-dessus) the mouth, just below the
cheliceree (antennes pinces), and wedged in, so to speak, between the foot-jaws.
Jt is a little flexible appendage, thinner towards its extremity, sensibly
dilated laterally, convex above, and beset, chiefly at the end, with fine and
silky hairs. This piece presents two apodemata (apodemes d’insertion),
which diverge greatly from one another.

“One finds a certain difficulty in positively determining the nature of the
single buccal appendage of the scorpion. It is impossible to regard it as
the analogue of the labrum (/évre supérieure) of insects. The labrum is one
of those pieces which abort most completely in the arachnida. Besides, in
all articulata, this labrum receives nerves which arise from the cerebral
ganglia. It is different with the buccal appendage of the scorpion ; its
nerves arise from the anterior part of the subcesophageal ganglia, exactly

* The livraisons of M. Blanchard’s work are unfortunately published
without dates.

252 HUXLEY, ON THE MOUTH OF THE SCORPION.

like those of the mandibles and maxille of Crustacea and Insects. It can
thus only be compared to these pieces; but ought we to regard it as repre-
senting both the mandibles and the jaws, or only the mandibles, or the jaws,
either one or the other being supposed to be aborted ?”

With respect to both the main points contained in these
paragraphs, however, M. Blanchard subsequently makes
statements which seem difficult to harmonise with the con-
clusions enunciated.

Thus, at page 41, I find:

“The pharyngeal nerves are two pair. Those of the first take their origin
from the anterior and median edge of the cerebrum, and almost imme-
diately unite so as to form a single nerve, whose branches are distributed in
the upper portion of the buccal appendage. It is evidently the analogue of
the nerves of the labrum of insects.”

And, again, at page 60:

“ Mouth and esophagus——The buccal orifice appears under the form of a
little transverse cleft, hidden under the cheliceree above (au-dessus) the
median appendage, which has already been described (p. 19); its edges are
flexible, and are deprived of asperities. The cesophagus, which commences
in a slightly funnel-shaped pharynx, is delicate, short, and widened pos-
terity, so as to resemble what M. Leon Dufour calls the ‘jabot’ in insects.
The cesophagus is held upon each side, towards its middle, by a fine mus-
cular band directed backwards, and towards its point of union with the
stomach by a similar band directed forwards. These muscles are attached
to the sternal floor, formed, as is known, by the basilar pieces of the ap-
pendages. ‘They serve to stretch the cesophagus either forwards er ey,
wards, so as to facilitate deglutition.

“The walls of the cesophagus are thin and smooth internally, and present
a few fine folds.”

In the figures (op. cit., pl. iv, figs. 1 and 6), which repre-
sent the anterior part of the alimentary canal, the oesophagus
is represented as a straight, taper tube, ending in the mouth,
without change of direction.

At page 32, M. Blanchard states, under the head of—

“ Muscles of the buccal appendage.—We have indicated the two, long, diver-
ging, apodemes of this piece (p. 19). Upon the base of each of them is
inserted an elevator muscle, provided with two fixed attachments to the ce-
phalo-thoracie shield in front of and external to the median eyes (pl. ii, fig.
4eeand fig.6 a). By its contraction, this muscle causes the buccal appendage
to be elevated a little—a movement which takes place when the animal intro-
duces foodintoits mouth. A transverse muscle is attached to the twoapodemie
plates (pl. ii, fig. 4,7); it is this muscle which, acting either on the one
side or on the other, determines the slight lateral movements of the buccal
appendage. It is to be observed, that this piece, solidly fixed between the
foot-jaws, sensibly involves the latter during the execution of its slight
movements.”

HUXLEY, ON THE MOUTH OF THE SCORPION. 258

The structure of the parts which I have observed in a large
species of Buthus may be described as follows :

The “buccal appendage” of M. Blanchard is a vertically
elongated, laterally compressed, cushion-like prominence,
broad and rounded above, where it is marked by a slight
median ridge, slightly concave from above downwards in
front, and narrowed below (Pl. XII, figs. 1, 2,36). Its
anterior and lateral surfaces are covered with fine, short hairs,
which form a projecting pencil at its anterior inferior angle.
There is no aperture whatsoever above this body, between the
cheliceree ; but, below and behind it, the aperture of the
mouth, large enough to admit the head of a fine needle, can
be very easily found. I entertain no doubt, therefore, that
this “ buccal appendage” is a true labrum, and, indeed, in all
essential respects, it is exactly like that part in the crustacea.

The convex lower surface of the labrum bounds the mouth
in front, while behind, it is hmited by a transverse thicken-
ing of the chitinous integument, which appears to represent
the sternum of the mandibular somite (fig. 40). The mouth
Opens into a very curious pharynx, formed by a delicate
outer investment, and a strong inner chitinous lining.
Viewed laterally, this organ (c) has the shape of a pear,
its broad end being uppermost, and its long axis directed
obliquely upwards and backwards, in such a manner, that
the broad upper end lies in the middle, between the prongs
of the fork-like apodeme, which M. Blanchard has de-
scribed. Viewed from above or below, however, the
pharynx appears to be very narrow, indeed, almost linear,
in consequence of its very peculiar form, which is displayed
in the section, taken transversely to the longitudinal axis
and perpendicularly to the vertical plane represented in fig. 5.
The cavity of the sac is here seen to be triradiate, while
its walls are very closely approximated, so as to leave but
a slight interspace. The narrow band which joins the
two lateral walls below and behind is slightly excavated, so
as to present a convexity towards the cavity of the pha-
rynx. The two shorter rays of the sac are turned upwards
and outwards; the third longer ray is directed vertically down-
wards. The esophagus, an exceedingly delicate and narrow
tube, comes off from the posterior wall of the vertical ray or crus
of the pharynx, just above the mouth ; and, widening, passes
backwards and upwards, into the dilatation which receives the
ducts of the so-called salivary glands (e). Just above the aper-
ture is a rounded projection (fig. 6 p), which I suspect may
act as a sort of valve, when the sides of the pharynx are diva-
ricated, by more or less completely occluding the cesophageal

254 HUXLEY, ON THE MOUTH OF THE SCORPION.

aperture. The inner surface of the chitinous lining of the
pharynx is more or less rugose; and, towards the cesopha-
geal aperture, presents a number of very minute spines (fig. 6).

The transverse muscular fibres (fig. 2), rightly said by M.
Blanchard to arise from the forks of the apodeme (m), are
inserted into the side walls of the pharyngeal sac, which is so
narrow from side to side, as readily to escape notice, without
dissection. The termination of the aorta appeared to me to
pass between the two superior crura of the sae.

The large vertical muscles (fig. 1 g) are, as M. Blanchard
states, inserted into the base of the apodeme; and, besides
these, the labrum is traversed by strong transverse and longi-
tudinal muscles.

The mode of action of this curious apparatus appears to be
readily intelligible. Scorpions, as is well known, suck the
Juices of their prey, and the pharyngeal sac seems to be
well calculated to perform the part of a kind of syringe.
For, suppose the prey to be held between the labrum
above, the bases of the great mandibles at the sides, and the
processes furnished by the maxillary limbs below, and that
the minute oral aperture is applied to a wound. Then,
if the transverse muscles (v) contract, the sides of the pha-
rynx will be drawn apart, and a partial vacuum, or at least
a tendency to the formation of one, will be created. If,
by the same action, the projection (p) is brought down
over the csophageal aperture, regurgitation from the ceso-
phagus will be prevented; but, in any case, as the oral
aperture is larger than the cesophageal, it will be easier for
the sac to be filled through the mouth. The sac being
full, if the labrum is depressed so as to close the oral aperture,
and the transverse muscles are relaxed, the elasticity of the
walls of the pharynx will tend to reduce its cavity to its
primitive dimensions, and hence to drive the ingested liquid
into the csophagus. Successive repetitions of the action
would gradually pump the juices of the preyinto the alimentary
canal of its captor. :

coe)
Or
Or

TRANSLATIONS.

On the Ortain of Ferments. New experiments relative to
so-termed Spontaneous Generation. By M. L. Pasteur.

(‘ Comptes Rendus,’ May 7, 1860, p. 849.)

Amone the questions arising during the researches which
I have undertaken on the subject of fermentations properly
so termed, there is none more worthy of attention than that
which relates to the origin of “ ferments.” Whence proceed
these mysterious agents, so feeble in appearance, and yet in
reality so powerful; which in the minutest quantity, mea-
sured by weight, and with insignificant external chemical
characters, possess such extraordinary energy? It is in an
attempt to solve this problem that I have been led to the
study of the so-termed spontaneous generation.

In the communication which I had the honour of sub-
mitting to the Academy on the 6th of February last, I men-
tioned only a single fluid appropriate for the development of
Infusoria and Mucedinea, although I gave a general method
applicable to all liquids.

On that occasion I showed, in a manner that has been
contested only in appearance—First, that the solid parti-
cles conveyed in the atmospheric air were the origin of all
the vegetable and animal productions peculiar to the fluid in
question. Secondly, that these particles, examined under
the microscope, are amorphous, dusty atoms, constantly
associated with certain corpuscles, whose form, volume, and
structure show that they are organized after the manner of
the ova of Infusoria or of the spores of the Mucedinea.

I am, at present, in a condition to extend the assertions
contained in the communication of the 6th February to two
substances, still more alterable than the sugared water mixed
with albuminous matters which had been more particularly
the subject of my former experiments. I now speak of

256 PASTEUR, ON FERMENTS.

“ milk” and “ urine.” The details of the results derived
from these two fluids will show, as I hope, the kind of
future in store for this department of study.

I introduce about 100 cubic centimeters of recent urine
into a flask capable of containing 250 cubic centimeters.
The drawn-out neck of the flask communicates with a
platinum tube, heated to redness. The liquid is made to boil
for two or three minutes, and then allowed to cool. When
refilled with air, which has been subjected to a red heat, the
flask is hermetically closed.

The flask, under these conditions, may remain for an inde-
finite time in a stove, at a temperature of 30° C., without
its undergoing any alteration. After the lapse of a month
or six weeks, I cause a small quantity of amianthus charged
with the atmospheric dust to fall into the flask, the mode in
which this is effected being precisely that described in the
‘Comptes Rendus’ of the 6th of February. The neck of the
flask being then again hermetically closed, the apparatus is
replaced in the stove.

In order to be sure that the manipulation to which the
flask is submitted, for the introduction of the atmospheric
dust, does not itself in any way affect the result of the
experiment, I prepare a second flask similar to the other ;
only that, instead of allowing amianthus charged with
atmospheric dust to fall into it, I substitute the same amian-
thus previously calcined for some moments before its imtro-
duction into the flask.

The following are the constant results of the experiments
so made.

The fluid in the flask which has received the amianthus
deprived of the atmospheric dust remains unaltered at the
temperature of 30° C., whatever may be the duration of its
exposure to this heat, which is so favorable to the putrefac-
tion of urine. On the contrary, at the end of six hours,
the urine which has received the atmospheric dust, presents
organized products—Mucedinea or Infusoria. Among the
latter I have noticed chiefly Bacteria, very minute Vidbriones,
and Monads, in fact, the same Infusoria that 1 have found in
the same urine exposed to the contact of the atmospheric air
at a temperature of 80°C. During the followmg days will
be witnessed an abundant deposition of crystals of ammo-
niaco-magnesian phosphates and of the alkaline lithates.
The urine becomes more and more ammoniacal. Its urea
disappears under the influence of the true ferment of the
urine, a ferment which I have proved to be organized, and
whose germ could only have been introduced in the atmo-

PASTEUR, ON FERMENTS. 257

spheric dust, as well as that of the Infusoria or of the Muce-
dinea.

Milk exhibits still more interesting properties. I have
said that, before filling the flask with air which has been sub-
jected to a red heat, and hermetically closing it, I caused the
urine to boil for two or three minutes. This duration of the
ebullition is sufficient, and everything leads me to believe
that even less careful precautions will suffice to deprive of all
viability the germs which may have fallen into the urine
subsequent to its emission.

This being granted, let us repeat, without any change,
the operation above described—now, however, not upon
urine, but upon fresh milk; that is to say, after this fiuid
has been boiled for two or three minutes, and the flask has
been refilled with air heated to redness, let us keep it closed
at a temperature of 30°.

After a variable lapse of time—generally of three to ten
days—the milk in all the flasks thus prepared will be found
coagulated. Under the prevalent views respecting the phe-
nomenon of the coagulation of milk, there is nothing in this
circumstance to excite surprise. When milk, it is said, is
exposed to contact with the oxygen of the air, the albu-
minous element is altered and acts as a ferment. This fer-
ment reacts upon the sugar of the milk, and transforms it
into lactic acid, which then precipitates the casein. This is
the cause of the coagulation. In reality, however, things
are quite otherwise. For if one of these flasks in which the
milk is coagulated be opened, it is obvious, on the one hand,
that the milk is as alkaline as fresh milk; and on the other
-—a circumstance tending to encourage the belief in sponta-
neous generation—that the milk is filled with Infusoria,
most frequently with Vibrios, as much as jth millimeter in
length. As yet I have not met with any vegetable produc-
tion under these circumstances.

From these facts we must admit—First, that the pheno-
menon of the coagulation of milk, as I hope shortly to demon-
strate more clearly, is a phenomenon upon which we have
had but very imperfect notions. Second, that Vibrios may
arise in a liquid of the nature of milk which has undergone
ebullition for several minutes at a temperature of 100° C.,
although this is not the case with respect to urine, nor to a
mixture of sugar, water, and albumen. Is it the case, then,
that under particular conditions we may have spontaneous
generation? We shall soon see how far this conclusion
would be erroneous. Let the milk be boiled, not for two, but
for three, four, or five minutes, and it will be found that the

258 PASTEUR, ON FERMENTS.

number of flasks in which it coagulates from the presence of
Infusoria diminishes progressiv vely in proportion to the
longer duration of the ebullition. ‘And lastly, if the ebulli-
tion be carried on at a temperature of 110 to 112 degrees,
under the pressure of 14 atmosphere, the milk will never
afford any Infusoria. Consequently, as they do arise under
the conditions existing in the former experiments, this is
evidently due to the circumstance that the fecundity of the
germs of the Vibrios is not entirely destroyed, even in water
at a temperature of 100°, kept up for some minutes, and
that it is more affected by a longer ebullition at that tem-
perature, and wholly abolished at the temperature of 110° to
112° C.

But what is to be said concerning the phenomenon of the
coagulation under those special conditions of ebullition, in
which the milk in contact with calcined air never affords
any Infusoria? One remarkable fact is, that the milk does
not coagulate. It remains alkaline, and preserves, I would
venture to say, entirely all the properties of fresh milk.
Then if, mto this milk, thus retaining its integrity, the
atmospheric dusty particles are introduced, it changes and
coagulates, and the microscope shows the existence in it of
divers animal and vegetable productions.

It would be very interesting to ascertain whether the
fluids belonging to the animal economy, such as milk and
urine, contain normally or accidentally, previously to all
contact with the common air, the germs of organized pro-
ductions. This is a question which I hope to resolve in a
subsequent communication.

The generally admitted theory of ferments, and that which
of late years had received fresh support from the writings
or the labours of various chemists, consequently appears
to me more and more incongruous ‘with experiment. The
“ferment” is not a dead substance, without determinate
specific properties. It is a being, whose germ is derived
from the air. It is not an albuminous substance, altered by
oxygen. The presence of albuminous matters is an indis-
pensable condition of all fermentation, because the “ ferment”
depends upon them for its life. They are indispensable
in the light of an aliment to the ferment. The contact
of the atmospheric air is, pr imarily, equally an indispensable
condition of fermentation, but it is so in virtue of its being
a vehicle of the germs of the “ ferments.”

What is the true nature of these eerms? Do they not
require oxygen, in order to pass from the state of germs to
that of adult ferments, such as are met with in the products

POUCHET, ON ATMOSPHERIC CORPUSCLES. 259

undergoing fermentation? JI have not yet arrived at any
fixed conclusion with respect to these grave questions. I am
endeavouring to pursue the inquiry with all the attention it
merits ; but the really capital difficulty of these studies con-
sists in the isolated, individual production of the various
ferments. I may assert that there are a great many distinct,
organized ferments, which excite chemical transformations,
varying according to the nature and organization of the
ferment. But in most cases the nutriment suitable to
some allows of the development of others of them, whence
arise the most complicated and the most variable phenomena.
If we could only isolate one of these ferments, in order
to develop it by itself, the chemical transformation cor-
responding to it would take place with remarkable precision
and simplicity.

I shall, in a short time, give a new instance of this, in
describing the organized ferment proper to the fermentation
termed “ viscous.”

Researches on the Corvuscies imtroduced by the Armo-
SPHERE into the Respiratory Orcans of Animats. By
M. F. Povucuer.

(‘Comptes Rendus,’ 1860, p. 1121.)

I wave thought for a long time that the study of the
bodies conyeyed by the air mto the respiratory passages of
animals would offer imteresting physiological results, and
throw considerable light upon the subject of atmospheric
Micrography. Nor have I been deceived in this. In fact,
in almost every class of animals, the examination of the
respiratory apparatus clearly reveals the various modifi-
cations of the medium inhabited by them. But it seemed
to me that the most important notions on this subject would
be presented in those animals in which the air penetrates
the most deeply into the organism. Birds, consequently,
have become the objects of particular attention, seeing that
in them the air, after traversing the lungs, pervades not only
the different cavities of the trunk, but reaches also the inte-
rior of the osseous system. In these animals I have devoted
particular attention to the examination of the bones which
contain most air, and chiefly to the humerus. And as in

260 POUCHET, ON ATMOSPHERIC CORPUSCLES.

these situations the corpuscles, once introduced, escape only
with great difficulty, owing to the immobility of the walls
and the irregularities of their anfractuosities, we there find
ample vestiges of all the matters conveyed by the air into
the respiratory organs.

The examination of animals living in the midst of towns,
and in the interior of our dwellings, will excite surprise by
the enormous quantity of starch-grains contained in their
respiratory organs. In birds, corpuscles of this nature will
be discovered in great abundance, even in the interior of the
bones, and together with them will be observed, in profusion,
particles of sooty matter and filaments derived from the
various fabrics of which our clothes are made. But the fur-
ther the creature lives from towns, the more remote and
wild its habitation, the more rare also become all these cor-
puscles in the inspired air. Under these circumstances,
searcely any traces of the sort can be observed. Fre-
quently, even not asingle particle of the kind in question
will be observed in animals or birds living altogether in the
midst of forests; in these animals, on the other hand, the
whole respiratory apparatus is filled with abundant débris of
plants,—epidermis, chlorophyll, &c.

The amylaceous particles disseminated either in the atmo-
sphere or in the interior of animals present two conditions—
they are either in the normal state or cooked. In the
majority of cases the starch is found in the former condi-
tion; but, nevertheless, we frequently meet, in the atmo-
sphere, and in all the cavities of animals into which the air
enters, with starch-grains, either simply swelled or entirely
burst by the action of heat. The latter certainly proceed only
from minute particles of bread carried about by the move-
ments of the atmosphere. This panified starch is readily
recognised by its enormous size and ruptured condition, and
by the action of iodine, which does not produce in it the
same bright colour as it does in ordinary starch-grains.

The birds which inhabit the mterior or live in the close
vicinity of towns do not obtain this abundance of amyla-
ceous particles simply from the air they inspire; they derive,
besides this source, an abundant supply from the foliage of
the trees amidst which they pass part of their lives. In
fact, on examining the surface of the leaves of trees in the
neighbourhood of cities, when they have not been washed for
some days by rain, abundance of specimens of every sort of
corpuscles carried in the atmosphere will be found on them,
and, universally, a considerable quantity of starch-grains,
together with sooty and siliceous particles. On a single leaf

POUCHET, ON ATMOSPHERIC CORPUSCLES. 261

of a Horse-chestnut, growing in the garden of the Ecole de
Médecine at Rouen, I have counted about thirty grains of
wheat-starch, either in the natural or panified condition.

The search for atmospheric corpuscles in the respiratory
passages is easily made. It consists simply in the passing of

a stream of water through these passages, and the collection
oe examination of the fluid. For this purpose I inject
the trachea, by means of a syringe, and when the lungs are
distended with water, make incisions into them, and care-
fully collect all the fluid that escapes, repeating the injec-
tion several times.

In birds I inject the trachea, and when the water has
traversed the lungs and filled all the air-cavities of the
body, I open the thoracie cavity, and collect the liquid
which escapes in a jet. In all the experiments the fluid is
received in conical vessels, with a narrow bottom, and when
sufficient time has elapsed to allow all the corpuscles to sub-
side these are removed by means of a very slender pipette,
and submitted to microscopic examination. The atmo-
spheric corpuscles may be collected from the hollow bones
by the same mode of procedure. To effect this, I imsert the
tube of a syringe into the orifice, by which the air pene-
trates into the cavity, and then make a section of the bone
at the opposite end. The water injected, at first gently,
and afterwards with great force, in order to carry along with
it the smallest corpuscles, is received in champagne-glasses
and examined. Studied in this way, the respiratory organs
afford a faithful idea of the life of the animals. Not only
does the examination reveal to us what sites of habitation
the animals prefer, and their kind of food, but even, when
they are domesticated, the profession followed by their
owners.

I have found in the air-passages of man the same atmo-
spheric corpuscles as are with met in animals. In the bodies
of two persons who died in one of our hospitals, a man and
a woman, whose lungs I injected, I found a large quantity
of wheat-starch, either normal or panified; particles of silex
and of glass; fragments of dye-wood, of a beautiful, red
colour; fragments of dress and, lastly, a larva of a micro-
scopic arachnidan, still living.

It was rational to conclude that, at certain times, the
expectoration should contain corpuscles similar to those J
have described in the lungs. And this is actually the case;
I have here met with normal and panified starch-grains,
particles of soot, the débris of plants, filaments of wool or
cotton of various colours, particles of silex, &e.

262 POUCHET, ON ATMOSPHERIC CORPUSCLES.

A fowl, brought up in a paved court at Rouen, afforded in
its respiratory sacculi an enormous quantity of wheat-starch,
normal and panified. Besides which they contained numer-
ous filaments of cotton and of lnen, and an abundance of
sooty particles; there were but a very few siliceous grains,
a circumstance probably owing to the habitation in which
the bird had existed. The humerus of this bird also con-
tained much starch, particles of soot, a considerable number
of cotton and linen filaments, and even some grains of
potato-starch and of glass.

Thinking that in animals living in localities where starchy
matters formed an object of trade, the abundance of amy-
laceous particles would be still greater, I procured two young
chickens which had been kept for two months by a baker.
My surmise was not unfounded. The whole of the respi-
ratory organs in these chickens, notwithstanding their youth,
contained an amount of starch surpassing that which I had
found in the fowl.

A pigeon taken from a dove-cot in the middle of the town
presented, in its respiratory passages, besides particles of silex
and soot, the débris of stuff of various colours and a few
grains of potato-starch, together with a considerable amount
of wheat-starch of all sizes, and, above all, an enormous
quantity of lentil-starch. Even the humert contained so
much of the latter, that from eight to ten grains were found
in every case. Iwas unable to explam the presence of such
an abundance of lentil-starch ina bird which always swallows
seed without bruising it. But I very soon discovered the
source on examining the floor of the dove-cot. This was com-
pletely covered with the dung of the pigeons, containing an
enormous quantity of this sort of starch, which had passed
through the intestines unaltered. In flymg about in their
dwelling the birds diffused this in the air, and it thus gained
an entrance into their respiratory organs.

The examination of a bird which is ordinarily kept only
in wealthy establishments affords another proof of what
has been said. In fact, the numerous vestiges of magnificent
stuffs exhibited in its respiratory organs manifestly recalled
the luxurious dresses or works of those amongst whom it had
it had lived. This bird wasa peacock. Unfortunately I had
at my disposal only its Aumeri; but having injected them, I
was really struck with the abundance of, and the splendid
colours presented by, all the fragments of stuffs contained in
these bones. I found, besides a considerable quantity of
wheat-starch, numerous filaments of wool and of silk of the

ost magnificent blue, of a beautiful rose, and bright green.

POUCHET, ON ATMOSPHERIC CORPUSCLES. 263

The lungs of a Mouse also afforded starch, silex, and
soot, but in far less quantity and in far smaller fragments
than in the birds.

But if our attention be directed to wild birds, residing at a
distance from cities, we observe a totally different thing.

A Gray Falcon (Falco cineraceus, Mont.), killed in a large
forest two leagues from any habitation, did not afford the
least trace of starch, either in its air-passages or within the
bones. There were met with only a few particles of soot
and silex; and not a single filament of any kind of tissue
was recognised. But, on the contrary, all the air- passages
were filled with an abundance of the detritus of plants and
débris of insects.

In another wild bird (Picus viridis, Linn.) I found in
the air-passages only an insignificant quantity of starch, and
very little soot and silex.

In some frogs taken in the basins of the Jardin des Plantes
at Rouen, which is situated close to numerous factories
and in a populous quarter, the lungs have always afforded
a notable quantity of starch, an abundance of particles of
charcoal and coal-soot, together with numerous fragments of
silex and vegetable débris. Besides these, filaments of cotton,
raw or manufactured, were extremely abundant. ‘The respi-
ratory organs of these animals also contained Navicule,
diatoms, papilionaceous scales, the stems of mucedinous fungi,
and fragments of Confervee.

If, again, we explore the respiratory passages of some
animals which, although living in a state of liberty, are in
the habit of frequenting our dwellings, we find m them
evident vestiges of their double existence, wild and domestic.

A Jackdaw afforded a striking instance of this. Its respi-
ratory organs contained a very considerable quantity of
wheat-starch ; and what was very remarkable, an enormous
number of sooty particles—a circumstance which is accounted
for by the almost habitual abode of this bird on the lofty
buildings of towns. There were found also, in its air-sacs,
numerous filaments of cotton and abundant débris of plants.

In all my observations, which, without exaggeration,
might be counted by hundreds, I have never met with either
a single spore or a single ovum of a microzoon, nor with
any encysted animalcule. Moreover, if in all these minute
researches I have always been able to detect starch-grains
wherever they existed, is it possible that the atmospheric spores
and ova alone should have escaped detection? ‘The ova of
certain Paramecia, bemg ‘0420 mm. in diameter, and conse-
quently surpassing considerably in bulk the largest grains

VOL. VIII. X

264 BAUR, ON CHITINE.

of wheat-starch, whose diameter does not exceed ‘0336 mm.,
if they really existed in the atmosphere in sufficient quantity
to explain the generation of Infusoria, whose apparition
astonishes and stupifies us, should have been immediately
discovered in the same situations, and far more easily even,
than the starch-grains, seeing that they ought to exist in
much greater numbers. To a negation of this kind, in the
actual state of science, but one answer is possible—show
these ova.

On Cuitine. By M. A. Baur.

In ‘ Reichert’s Archiv’ for 1860," part 1, M.°A. Baur
has published an interesting memoir on the chitinous tendons
of Articulata, and their relation to the change of skin.
The simplest and oldest view of these structures regarded
them as being nothing more than inward prolongations of
the outer skeleton, resembling true tendons, but not as
corresponding to those of the Vertebrata, which consist
of connective tissue. Leydig, on the other hand, considers
that these tissues do correspond to one another, and that,
while the tendons of Vertebrata often become bony, those
of Articulata tend to change themselves into chitine.

If, indeed, as has been supposed to be the case, the chitine
and connective tissue of the tendons are in continuous
connexion, and pass gradually into one another, then we
should be forced to consider them as nearly allied, and that
chitine is, in fact, a modification of connective tissue.

This view of the question is maintained by Leydig, but on
the other hand is opposed by Hickel and Kolliker, accord-
ing to whom the chitine of the Articulata is a laminated
secretion of the epithelial cellular layer. The external chitine
is known to be continuous with the intima of the intestinal
canal, and this latter is admitted by Leydig to be a secretion
of the epithelium. The theory supported by Hiackel and
Kolliker has, therefore, this advantage, that it does not
disunite structures which are histologically identical, but
considers the whole chitine skeleton of the Articulata from
one point of view. If, however, it is correct, then it
becomes a general characteristic of chitine that it always
forms the boundary of free surfaces, or the lining of those
that are turned inwards.

BAUR, ON CHITINE. 265

To this law, however, chitinous tendons must, according
to the ordinary opinion, form an exception, since in them
the chitine forms a solid substance, and is continuous
with connective tissue. An epithelial secretion and con-
nective tissue cannot, however, possibly be continuous with
one another, since they must, at least, be separated by the
epithelial layer to which the former owes its existence. If,
therefore, chitine is the secretion of an epithelial layer,
the tendons may pass into it, or may pass into the connective
tissue, but assuredly not into both. In the first case
the apparent chitine of the tendon is really a process of
the outer skeleton ; in the latter it is true connective tissue.
Hackel endeavours to prove the latter of these two alterna-
tives, considering that the chitine of chitinous tendons pos-
sesses neither the fine canals nor the cell-impressions which
are found in true chitine. According to Leydig, on the
contrary, chitinous tendons prove that ordinary chitine
is, in fact, a modification of connective tissue.

The controversy may be reduced to the following questions :
—Are the chitinous tendons continuous with the outer skeleton
only, with the connective tissue only, or do they pass
insensibly into both? In the first case the tendon is a
continuation of the outer integument, in the second it is
composed of modified connective, and in the third case the
chitinous outer skin must itself be regarded as an abnormal
form of connective tissue.

In the ordinary state of the tissues these problems are
difficult of solution, but they become comparatively easy
if we examine an animal at the time of moulting. It is
well known that the tendons are cast with the skin. If
one takes a crayfish which is just about to moult, we shall
find the soft new skin lying under the hard old one: if we
now isolate the mandibular muscle, so that on the one side
it is attached to the back of the cephalothorax, while on
the other its tendon is united to the mandible; and if we
remove from the latter its old chitinous covering, which
can generally be effected without much difficulty, the
chitinous tendon will come away also. The muscle does
not, however, thereby lose its attachment to the tendon, but
as under the old, hard skin of the mandible, a new and soft
one is formed, so also, instead of the old tendon, we find a
new tendon, which is attached to the new mandible. The
new tendon resembles the old one in form and sculpture,
but it differs from it in consistence; and also in this, that,
while the old tendon is apparently solid, the new one is
distinctly tubular—and, in fact, the old tendon lies in the

266 BAUR, ON CHITINE.

hollow of the new one. The new tendon, however,
remains hollow only for a short time; and when the old
one has been pulled out, its walls gradually close in upon
one another, and it soon puts on the appearance of a solid
body.

The integuments of the crayfish consist, as Hackel has
correctly shown, of an outer layer of chitine and an inner
skin composed of connective tissue. ‘These two, however, are
never continuous with one another, but are always separated
by a number of cells, or rather, perhaps, of nuclei, which form
a single layer, and are specially evident at the time of moult-
ing. The new layer of chitine is formed between the old one
and this layer of cells, and it is therefore evidently produced
by them. The connective tissue, which is of variable thick-
ness, has therefore no chitinogenous function, and serves only
as a substratum for the true chitinogenous layer. At the
time of moulting another layer, that is to say the new chitine,
is added to the three layers always present ; this is equally
true for the tendon as for the mandible, but with this differ-
ence, that the latter being a projection, and the former an
inversion of the skin, the order of sequence of the layers is
reversed. This structure is not confined to the main stem
of the tendon, but is repeated in its branches; each one of
these presents the same arrangement, but the outer con-
nective tissue increases in size at the expense of the chitine,
which finally disappears where the muscle commences, so that
the sheath of the muscle is formed by the expansion of the
layer of connective tissue only.

Hiickel denies that the pore-canals, which are so character-
istic of true chitine, exist in chitinous tendons. Certainly in
a longitudinal section no trace of them can be perceived ; but
if the tendon is cut transversely, besides the laminar structure
a radial shading may be perceived, like that which is seen in
sections made at other parts of the chitine skeleton, and
which is referred to the presence of pores. Here, however,
evidently no pores are present ; and without wishing to deny
that they do occur in other parts, it may at least be asked
whether the appearance presented has not been, in this
respect, misunderstood. The cell-impressions are also absent
in the chitine of tendons, as indeed in some other parts of
the skeleton, but certainly these two differences are not
sufficient to prove that the tissue in question is not true
chitine.

The principal conclusions to which M. Baur arrives are
that the so-called chitine tendons are inwardly projecting, ori-
ginally tubular, subsequently solid, and more or less branched

BAUR, ON CHITINE. 267

portions of the general integument. 2dly. That the tendon is
composed of the same layers as the skin, but with an inverted,
concentric arrangement. Thus the external chitine of the
outer skin is continuous with the inner chitine skeleton of the
tendon, the lower connective-tissue layer of the skin with
the connective-tissue sheath of the tendon, and this only is
immediately connected with the connective tissue of the
muscle. 8dly. The chitinous skeleton of the tendon is cast
with the skin at every moult ; and this is true, not only of
the main stem, but also of its finest branchlets. 4thly. Con-
tinuity between chitine and connective tissue never occurs
but in the finest branches of the tendons, as everywhere else
they are separated by a layer which secretes the chitine.
5thly. The chitine of the tendons does not in reality differ
from that of the general integument ; the apparently fibrous
condition, and the longitudinal striation, and the capability of
being split, all arise from the folding of the homogeneous
lamelle, which takes place after the removal of the old
tendon, and when the young chitine has already attaimed a
certain degree of hardness.

The chitine of the tendons forms therefore no exception to
the general rule, that this structure occurs only as a cover-
ing of free surfaces; and the chitinous tendons can no longer
be relied on as a proof of the connexion which has been sup-
posed to exist between chitine and connective tissue. Since,
however, the chitine of tendons possesses no pores, nor any
cell-like impressions, these conditions can no longer be re-
garded as necessary to true chitine, and the characteristics of
chitine are therefore reduced to these, that it bounds sur-
faces, consists of a variable number of homogeneous lamelli,
possesses a certain power of resisting chemical agents, and is
constantly accompanied by a soft and thin layer, consisting of
a simple series of nuclei connected together by a molecular
substance. ‘Taking it therefore for proved that chitine is not
to be regarded as a form of connective tissue, M. Baur con-
cludes his memoir by considering in what manner it is pro-
duced by the chitinogenous layer. This might be effected in
two ways; either this layer might be changed imto chitine, in
which case it must be regarded as an immature form of chi-
tine; or the chitine might be directly produced by the
chitinogenous layer. In the first of these cases, however,
we ought to find layers in every intermediate state between
chitinogenous tissue and true chitine, which is by no means
the case. On the contrary, even the youngest lamelle are
true chitine, and show no resemblance to the chitinogenous
layer.

268 BAUR, ON CHITINE.

It would seem therefore that Kolliker and Hickel are
right in considering that chitine is secreted by a subjacent
chitinogenous tissue ; though, as this latter cannot be broken
up into separate cells, it may be doubted whether it can be
correctly termed a layer of epithelial cells,

269

NOTES AND CORRESPONDENCE.

The Nose-piece"Finder.—My observations on the nose-piece
finder (inserted in your last number) have drawn me into
a little controversy with a scientific gentleman of great micro-
scopic experience.*

He says, “I have just read your remarks on the applica-
tion of the double nose-piece as a ‘finder.’ It is, of course,
as good a one as we can have, provided the object is large
enough, or sufficiently opaque, to be seen by the 14 objective :
but when it is with great difficulty seen with the 1-inch, the
“nose-piece, as a finder, is useless,’”? &e.

He then instances several of the smallest examples of
Diatomacee (e. g. Eunotia Bactriana), which are so exceed-
ingly minute and (when prepared in balsam) so exquisitely
hyaline, that it is to be doubted if they can be discriminated
with so low a power as 11-inch, &e.

These objections have set me upon a very careful course of
examination and trial; for nothing could be more unpleasant
to me than to find that I had misled any one by an erroneous
statement. But I am happy to say that the result has been
rather a corroboration of my former assertions, with only this
modification, that more ought to have been said on the
subject of eye-pieces; for a 14-inch objective acting along
with eye-piece a is very different from the same with eye-
piece p, &c. Then, again, eyesights differ in quality ; some
individuals being able to see a smaller speck with a 2-inch
objective than others can with 1-inch, and so on.

With 13-inch objective and eye-piece a I can very dis-
tinctly see the spot in the centre of P. angulatum. With
eye-plece p an object not a fourth part that size might be
seen so as to be perfectly recognised.

The same combination will also distinctly show the reticu-
lations ona scale of Morpho Menelaus.

* Mr. F. Kitton, of Norwich.

270 MEMORANDA.

Moreover, some persons do not use a lower power thau
1-inch ; and, if so, and that lens be employed as the “ finder”
with eye-piece p, I do not believe there is any organic object
that cannot be distinctly discerned thereby; as that com-
bination will clearly show a particle suttciently small to
pass through the mesh in the above-mentioned scale (taken
from the under side of the wing), which meshes I find, by
micrometrical measurement, to average about =,5th of an
inch in length and +5,;455th in breadth.*

This, as formerly said, I will undertake to prove to any
one who may think it worth while to come here for the
purpose.

So that, to shorten the matter as much as possible, the
entire question may be resolved into the following heads:

Ist. The double nose-piece is amply sufficient for the im-
mediate finding, with the highest powers, of all the generality
of objects, even those which are totally invisible to the un-
assisted eye.

2d. Those objects that are difficult of detection with so
low a power as 11-inch are (comparatively) very limited in
number; and that any of them are impracticable (with eye-
piece p) I have great doubt.

dd. Eyesight differs greatly in quality in different people ;
so that microscopists must be cautious in pronouncing ‘ that
will never do,” &c., when the whole truth is, that will never
do for me.

For my own part I am more and more pleased with the
*nose-piece finder,” and am using it continually, to my
very great comfort ; but for the benefit of those who are not
satisfied with it, and are especially bent on screwing their
unfortunate optic nerves to hunt out those excruciatingly
small objects which they cannot jind with inch objective and
eye-piece p, it may be well to state that of all the finders
hitherto devised on the graduated-plate system, Mr. Kitton
gives the preference to that of Mr. Maltwood, described in
your journal for April, 1858.

In conclusion, my remarks have been given upon the
principle of “valeat quantum valere potest,’ and my readers
will now, of course, do as they please in the matter; but I
cannot refrain from giving them a well-meant caution, that
the less they strain their “ visual optics” over these almost

* These measurements were made by means of the good old stage-micro-
meter, with which Mr. Powell used to supply his instruments many years
ago. I think highly of it, and do not know why it is now so rarely made.
One turn of the wheel is the y4;th of an inch; and the wheel being divided
into 100 degrees, one degree equals yabooth.

r

MEMORANDA. 271

infinitesimally minute “marvels of the microscope” the
better it will be for them if they are spared to enter those
years of senility to which, I regret to say, I am rapidly
approaching; or, in vulgar speech, youll smart for it if you
live to be old fellows——Henry U. Janson, Pennsylvania
Park, Exeter.

Composition of a Blue Transparent Injecting Fluid for Anato-
mical and Pathological Preparations—Not having been very
fortunate in preserving microscopic injections of tissues made
with the very beautiful blue fiuid recommended for the pur-
pose by Dr. Lionel Beale,* I was mduced, in conjunction
with Professor Barker, of Dublin, to endeavour to discover a
blue fluid of a less fugitive disposition than the one
alluded to.

Having performed many experiments with different inject-
ing fluids, we found that tissues injected with a colour of the
same chemical composition as Turnbull’s blue, are not so
hable to fade as those injected with the Prussian blue.

When ferridcyanide of potassium is added to a salt of the
protoxide of iron, a beautiful blue precipitate is the result.
It is somewhat brighter in tint than Prussian blue, and its
colour is unexceptionable.

Having been very successful in preserving preparations made
with this blue, we thought we should not lose any time in
mentioning the proportions we found to answer best for
making a free-running injection.

Composition of the blue fluid :

Purified sulphate ofiron : iy PO ets
Ferridcyanide of potassium . s wShityOhe, mated
Glycerine (Prices); ..- : 1 oz.
Wood naphtha or pyro- -acetic esprit . 14 drachm.
Spirits of wine . . : : 1... 0%,
Water : - ; A : : 4,

PP

Dissolve the sulphate of iron in one ounce of the water, and
the ferridcyanide of potassium in another ounce, then gra-
dually mix the two solutions in a large bottle, shaking well
during the mixture. Next add the naphtha to the spirit, the
glycerine, and the remainder of the water. Finally, add this
mixture to the Turnbull’s blue, and again shake well while
they are mixing.

Those familiar with Dr. Beale’s fluid will perceive that the
difference between it and the one we recommend only con-

* “How to Work with the Microscope,’ p. 78.

272 MEMORANDA.

sists in the materials for making the blue, the other in-
gredients are similar to his, and we have found them to
form an admirable combination for suspending the insoluble
and minutely divided precipitate.

In order to mount injections made with the Turnbull’s blue,
the following plan is recommended :

If the injected sections will bear it, they should be well and
repeatedly washed with cold water. Portions of the kidney,
for instance, we have left in water for three or four days,
changing the latter frequently during the period. When
thoroughly washed, they should be placed, for a week or
more, in glycerine, acidified with dilute muriatic acid, and,
lastly, mounted in cells with some of the following solution.

Composition of the preservative fluid for the blue in-
jections :

Glycerine (Price’s) ; ? E : 5 drachms.

Creasote and naphtha fluid (Beale’s*) . + drachm.

Dilute muriatic acid. : : 3 a trace.

Mix.
—Bern. Wiis Ricuarpson, F.R.C.8.1., Dublin.

On Extravasations of Blood, and the production of Aneurisms
caused by Parasites—An interesting paper on this subject,
chiefly with reference to appearances often observed in the
frog, is published (Reichert and Du Bois Reymond’s
‘ Archiy’ for 1860, p. 195) by Louis Waldenburg. The con-
clusions at which the author arrives are the following :

1. The hematode cysts of the frog contain altered blood,
due to extravasations produced by nematode worms which
have migrated into the blood-vessels.

2. The horny filaments met with in the mesentery and
coats of the intestine in frogs are bodies of foreign origin,
which have gained admission from without into the circula-
ting system of the animal. They are lodged in true
aneurismal swellings of the blood-vessels caused by their
presence, are surrounded by a thrombus, and are at the same
time the cause of the numerous minute cysts observed in
their vicinity, and which are also to be regarded as encysted
aneurisms.

3. The pigment-follicles attached to the vessels in the
spleen, liver, and kidney of fish, and which contain Psoro-
spermia, are also aneurisms caused by animals from which
the Psorospermia are derived, and which animals are found in
the vessels.

* “How to Work with the Microscope,’ p. 36.

MEMORANDA, 273

On a new Reagent for the Exhibition of the Axis-Cylinders in
Nerves.—I believe the fact I am about to state worth publi-
cation, as I am not acquainted with any other reagent which,
in perfectly fresh nerves, immediately renders the axis-
cylinder so distinctly visible. My experiment consists in
first splitting open the neurilemma with the needle, and
then, without the addition of any finid, in gently spreading
out the fibres upon the glass slide. I then immediately
place a drop of collodion on the preparation, and cover it with
the thin glass. Immediately, and in all the fibres, the most
beautifully defined axis-cylinders are rendered apparent ;
the medullary matter asswming a fine, granular aspect.*—Dr.
Epwarp PrivceEr.

High Powers—In a foot-note to p. 145 of the “ Proceed-
ings of the Microscopical Society,” published in No. XXXI
of the Journal, it is stated that Mr. Wenham has constructed
an object-glass of =,th of an inch focal length.

This announcement was, doubtless, hailed with much
satisfaction by all who, lke myself, believed that the
microscope had not yet reached the useful limit of ampli-
fying power, and microscopists are much indebted to Mr.
Wenham for his continued exertions in the improvement of
the instrument.

It is not, however, with a view to flatter Mr. Wenham
that I now write, but to remind that gentleman that it will
depend mainly, if not entirely, upon the discoveries he may
be able to announce, whether the use of these high powers
shall be limited to himself or become available to all who
may be able and willing to incur the expense. I have been
informed that our best makers declare there is nothing to be
gained by the use of higher powers than those they now make,
and yet Beck and Co. supply two, Ross three, and Powell
and Lealand four additional eye-pieces to increase the
power of the object-glass! although they know that, even
with their excellent workmanship, power is only gained in
this way at the expense of light and (too often) of defini-
tion. This seems in contradiction to their declaration. If
nothing be really gained by increase of power in the object-
glass, why give us anything beyond the first or, at most,
second eye-piece? The truth, however, I believe, is this. Eye-
pieces are easily made, and their small price places them within
the reach of all; but to increase the power of the object-glass

* Reichert and Du Bois Reymond’s ‘ Archiv u. d. Anat. Physiol.,’ 1859,
p. 132.

274 MEMORANDA.

would be attended with difficulties, perhaps, at least for a
time ; and if they were sold at prices proportionate to those
now charged for the ~;th and ;/;th, it is probable there
would be but few purchasers. It is these considerations, I
believe, and not the uselessness of higher powers, that make
our opticians say nothing is to be gained by increasing the
power of the object-glass.

Mr. Wenham will, I hope, consider it his high privilege
to show, not only that higher powers are useful, but that
they may be sold at moderate, yet remunerative, prices. No
one is more ready than I[ to admit that the labourer is
worthy of his hire, but if we are to have (as I hope we shall
have) glasses of much higher power than those now made,
and are to take the denominator of the fraction* expressing
their focal length as the number of pounds sterling of their
price, it is certain few will be willing, even if able, to incur
so large an outlay upon a single object-glass.—J. Mircue..,
Lieutenant, Madras Army.

* Powell’s 1-16th costs £16. At this rate, a 1-50th, of course, would
be £50, a price that would place it beyond the reach of any but the most
wealthy. There is something that I, at this distance, cannot understand in
the difference of prices by different makers. Powell and Lealand charge
10 guineas for a 1-12th, and Ross £18. But no one will say that one
glass performs better than the other—a bit of information, by the way,
that would be useful to people in the colonies,

ZOOPHYTOLOGY.

Descriptions of New Potyzoa from Irevanp.
By Rev. Tuomas Hincxs, B.A.

THE new species of Polyzoa which are described in this
paper have been obtained from material dredged in deep
water, off the coast of Antrim, by Mr. Hyndman of Bel-
fast, whose researches, as a member of the North of Ireland
Dredging Committee, appointed by the British Association,
have yielded so many valuable results.

Sub-order CHEILOSTOMATA.

Fam 1. MeEMBRANIPORIDE.
Gen. 1. Membranipora.
1. M. imébellis, n. sp., Hincks. Plate XXX, fig. 1.

Cells ovate, broad below, with a membranous covering (no calcareous
expansion); margin raised, much thickened, and beaded. Ovicell very
prominent, frosted, with a raised edging round the front. No spines nor
avicularia.

The examination of a large number of specimens from
various localities, exhibiting a striking uniformity of charac-
ter, has convinced me that this form should be accounted a
species, and that it is not a mere variety of M. Flemingii.

I have never detected, even in the youngest and freshest
specimens, any trace of spines or avicularia. The polyzoary
is generally dull and opaque, and coarse in texture.

The size and distinctness of the cells, the absence of the
calcareous expansion, the shape of the ovicell, and the want
of spines and avicularian appendages are constant characters,
which separate this species from M. Flemingit.

Common on shell, &. Coast of Antrim, Mr. Hyndman ; Scotland (west
coast) ; Devon.

Gen. 2. Lepralia.
1. ZL. alba, n.sp., Hincks. Plate XXX, figs. 2, 2 a.
Cells sub-ovate, broad, somewhat depressed, granular; mouth rounded

above, lower margin straight, with a notch in the centre; an avicularium on
each side, about half-way down the cell; mandible acute, pointing upward.

276 ZOOPHYTOLOGY.

Ovicell small, depressed, closely united to the cell above, surface finely
granular.

On shell, coast of Antrim.

2. L. eximia, n. sp., Hincks. Plate XXX, figs. 3, 3 a.

Cells large, ovate, distinct, granular, punctured round the margin; mouth
sub-quadrate, with a raised peristome, rising into a point at each side, a
broad, rounded denticle within the lower margin. Ovicell globose, promi-
nent, punctured.

This fine species grows in irregular, lobulate patches. My
specimeus exhibit neither spines nor avicularia.

On shell, coast of Antrim.

3. L. discoidea, Bk. Plate XXX, figs. 4, 4a.

Cells in straight radiating series ; immersed at the base, sub-erect above ;
surface punctured frosted ; orifice small, suborbicular, with a sinus below,
peristome raised; 4 to 6 marginal spines above; an avicularium on one or
both sides of the cell; mandible elongated linear, obtuse, directed down-
wards and outwards. Ovicell recumbent, punctured, its sides prolonged, so
as to surround the mouth.

Hab.—Antrim, on shell, 7. Hincks ; Madeira, J. Y. Johnson; Shetland,
Barlee.

This species has been figured twice already in former parts
of Zoophytology, but on both occasions from specimens in
which the true characters were not displayed.

An amended character, therefore, and a more correct
representation of the perfect form, is now given. Having
been furnished by Mr. Busk with specimens of the same
species, recently received by him from Madeira, through the
kindness of Mr. J. Y. Johnson, I am fully satisfied of the
identity of the Madeiran and Irish forms.

The characters above assigned are usually to be found
only on the marginal cells of the patch, which are also in
many cases double the size of the older or more central
cells; in the latter also the peculiar avicularia are almost
invariably wanting, being replaced in most instances by a
single, smaller, imperfect avicularium, placed rather to one
side on the front of the cell immediately below the mouth.
But it is very often the case that this organ is wholly want-
ing, when the species presents the aspect under which it was
formerly depicted.

4. L. Woodiana, Busk.

This species has been lately described and figured by Mr.
Busk in his ‘ Monograph on the Polyzoa of the Crag’
(p. 42, pl. vii, figs. 1 and 3), and was only known as a fossil,
previous to its occurrence amongst Mr. Hyndman’s Antrim
dredgings. From this rich material I have obtained one or

Y

ZOOPHYTOLOGY. 277

two specimens on shell, which correspond in all respects
with Mr. Busk’s figure. LZ. Woodiana must, therefore, take
its place as a member of our recent Fauna.

Fossil—Coralline Crag (Searles Wood).
Recent —Coast of Antrim; ? Madeira, J. Y. J.

There is every probability that many more of the Crag
forms may be obtained by careful investigation, and those
who may have opportunities of dredging, especially in deep
water, should be on the look-out for them. Mr. Busk’s
admirable Monograph, published by the Palszontographical
Society, affords a ready means of identifying the species.*

5. Lepralia Landsborovii, Johnston.

The description of this species in the ‘ British Zoophytes’
was founded on a single specimen, supplied by Dr. Lands-
borough, which is preserved in the British Museum. This
specimen is old and worn and by no means characteristic,
and it is not surprising that Dr. Johnston’s diagnosis should
have been so imperfect and unsatisfactory. Much difficulty
has been experienced in determining what form he had in
view, and there has been more than one claimant for the
honour of bearing the name.

In his ‘ Catalogue,’ Mr. Busk has given a very admirable
figure (pl. cii, fig. 1) of the veritable LZ. Landsborovii, but
has referred it to L. reticulata. A comparison of the form
represented in this figure (which I have procured abun-
dantly) with Dr. Johnston’s specimen, has satisfied me of
their identity.

The following is an amended description of the species :

Lepralia Landsborovit, Johnston, Brit. Zooph., 2d edit., p. 510.
$3 5 Busk, Catalogue of Brit. Mus. Polyzoa,
part ii, page 66, plate Ixxxvi, fig. 1 (taken
from the Brit. Mus. imperfect speci-
men) ; plate cii, fig. 1 (referred to J.
reticulata).

Cells ovate-elongate, separated by raised lines; surface lustrous, thickly
covered with punctures; mouth circular, a denticle within the lower
margin, peristome raised, with a spout-like sinus below, enclosing a small
avicularium, with a rounded mandible. Ovicell globular, prominent,
punctured.

* Since the above was written, Mr. Busk has furnished me with speci-
mens of a new Madeiran Lepralia, so closely resembling Z. Woodiana in
all essential characters, that I am strongly inclined to agree with him that
the two are identical. Thus is added another link to the already nume-
rous ones connecting the southern and western and north-western British
Polyzoa, with those belonging to the Mediterranean Fauaa, and to that of
the Crag.

278 ZOOPHYTOLOGY.

Dr. Johnston has accurately described the walls of the
cells as “ thin, glassy, and hyaline, thickly dotted with
small perforated granules.” In fresh specimens there is a
silvery sheen over the surface of the polyzoary. The avicu-
larium is placed within the projecting, spout-like sinus, into
which the peristome is prolonged below, and behind it
is a single denticle. The mandible of the avicularium is
rounded.

The ovicell is globose and punctured, and the sides of the
opening uniting with the peristome give a hooded appear-
ance to the cells on which it is developed.

My finest specimens of this Lepralia were dredged off the
Great Orme’s Head on the coast of North Wales, and were
some compensation for the general barrenness of the ground.
It occurred here in great abundance, commonly encrusting
masses of the sand-tubes belonging to a species of Sabella.
Over these it spread luxuriantly in large, sub-circular, and
glistening patches, occasionally rising into foliaceous expan-
sions. I have also met with it in Devonshire, and amongst
Mr. Hyndman’s dredgings from the coast of Antrim.*

Fam. 2. CELLEPORID2.
Gen. 1. Cellepora.
1. C. armata, n. sp., Hincks. Pl. XXX, fig. 5.

Polyzoary adnate, spreading; cells smooth, sub-erect (except towards
the margin of the polyzoary), ventricose, distinct ; orifice orbicular, slightly
produced below, peristome thin and raised; a stout rostrum in front,
with an avicularium at one side, immediately below the apex, mandible
acute and pointing upward; large spoon-shaped avicularia distributed over
the polyzoary, in the intercellular spaces. Ovicell smooth; walls entire.

In this species, the avicularium is placed at the top of the
rostrum, looking to one side. The broad triangular mandible
points upward. The rostrum is much stouter and more
obtuse than in C. pumicosa.

Localities —Coast. of Antrim, on shell, Mr. Hyndman; Dogger Bank
and South Devon, 7. H.; Madeira, J. Y. J., 1860.

2. C. avicularis, n. sp., Hincks.

A Cellepora occurs in considerable plenty on Zoophytes
from Ireland, which seems to be undescribed.
The following are its characters :

Polyzoary encrusting or spreading, variable in its mode of growth;
cells ovate, ventricose, smooth; orifice orbicular, with a deep sinus in

* Vide Report of Belfast Dredging Committee, in the British Association
volume for 1858, p. 293.

=

ZOOPHYTOLOGY. 279

front, a short, conical rostrum below the mouth, with an avicularium,
set obliquely, near the top of it, mandible acute; in fertile cells, a process
on each side, just below the ovicell, aud attached to it, bearing an oval (?)
avicularium. Ovicell prominent, with large punctures, somewhat semi-
oer disposed. Spatulate avicularia thickly scattered amongst the
cells.

Occasionally there occurs on the polyzoary a very stout, co-
nical rostrum, bearing a large avicularium, with broad, trian-
gular mandible.

Localities.—Treland, encrusting stems of Zoophytes, &c.

Sub-Order CycLosToMATa.
Fam. 1. TuBuLipokip&.
Gen. Alecto.
1. A. incurvata, n. sp., Hincks. Plate XXX, fig. 6.

Polyzoarium adnate, linear, curved, tapering; cells biserial, alternate,
bent towards the side, orifices opening out laterally; surface obscurely
punctate.

Polyzoarium closely adnate, narrow, unbranched, more or less attenu-
ated towards the point of origin; the cells are biserial and alternate
(except towards the base of the polyzoary, where they form a single row),
and separated by a median line; they bend towards the side, and project a
little beyond the polyzoary, the orifices opening out laterally.

On stones, coast of Antrim (deep water), not uncommon.

The Antrim dredgings have yielded a large number of the
Cyclostomata, belonging to the genera Tubulipora and Alecto,
which I am obliged to reserve for future examination.

Sub-Order CrenostoMaAtTa.

Fam. VESICULARIIDZ.
Gen. Farrella.

1. F. dilatata, u. sp., Hincks. Plate XXX, fig. 7.

Cells tubulous, sessile, stout, of equal size throughout, opaque, springing
from one extremity of a fusiform expansion of the fibre, which is closely
adherent, and set round with a number of flattened, spinous projections.

In this species the delicate, creeping fibre swells out here
and there into cell-like expansions, fusiform, adherent, and
furnished with a variable number of flattened, spinous pro-
cesses. The cells spring from the larger end of these swel-
lings. They are stout, sessile, and not contracted at the base,
and of a dark, horn colour when dried. The clavate and
spinous expansions are analogous to the cell-bearing enlarge-
ments of the fibre in Aiea.

Isle of Man, on shell, 7. H.; Antrim, deep water, Wr. Hyndman.
VOR: VIII: <r

280 ZOOPHYTOLOGY.

In the ‘ Belfast Dredging Com. Report’ for 1858, I have
recorded this species as Avenella dilatata. But the Avenella
of Sir John Dalyell is a very doubtful genus, and I prefer,
for the present, to refer it to Farrella, as defined by Mr.
Busk, in the ‘ Micr. Journal,’ vol. iv, p. 93.

II. Catatocusr of the Potyzoa collected by J. Y. Jounson,
Esq., at Maprrra, i the years 1859 and 1860, with
descriptions of the New Srrcizs. By G. Busk, F.R.S.

JL. CHEILOSTOMATA.
Fam. 1. CATENICELLID2.
Gen. 1. Catenicella, Blainv.
1. C. elegans, Bk.

Hab.—Madeira, on fishermen’s baskets, abundant, J. Y. J.; (?) Medi-
terranean, Savigny ; South Africa; Australia; New Zealand.

Fam. 2. SaLicornaniips, Bk.
Gen. 2. Salicornaria, Cuv.
1. S. Johnsoni, Bk.
Hab.—Madeira, J. ¥. J. ; Shetland, Buarlee.

Fam. 8. CELLULARIIDA, Bk.
Gen. 3. Scrupocellaria, Van Beneden.
l. S. Maderensis, n. sp.
Cellulis elongatis: aviculaiio parvo; orificio ovali, peristomate simplici

glabro; operculo suborbiculart glabro integro; spinis marginalibus sex,
equidistantibus ; ovicelluld glabra non punctata.

Cells elongated; avicularium small; orifice oval, peristome simple, not
granular; pedunculate epee nn sub-orbicular, smooth, entire; six equi-
distant marginal spines above ; ovicell smooth, not perforated.

Hab.—Madeira, J. Y. J.

This species differs from S. pilosa, Audouin (sp.), in several
respects. Ist. In the form of the cell, which in that species
is represented as elongated, and of nearly equal diameter
throughout, especially as viewed on the dorsal aspect. 2dly.
In the disposition of the marginal spines, which in S. pilosa
are depicted as four on the upper and outer margin, and a
single one some distance apart on the inner border of the
orifice. 3dly. In the ovicell, which in S. pilosa appears to
be perforated. They agree somewhat in general aspect, in

ZOOPHYTOLOGY. 281

the considerable number of spines, in the simple, smooth
peristome, and in the form of the pedunculate operculum.
As the only specimen brought on this occasion by Mr.
Johnson is small and imperfect, and has moreover been
injured since it came under my inspection, I have de-
ferred making a figure of the species until further specimens,
as I hope, may enable me to do so with greater advantage.

2. S. Macandret, Bk.

This species may be at once distinguished by the broad,
granular peristome, and contracted, sub-orbicular form of the
orifice. In the B. M. Cat., I have described and figured
it as being usually without marginal spines, but in the
present instance it has two or three on the outer and upper
margin, and one or sometimes two on the inner. From
S. Delilii, Aud. (sp.), it is distinguished by the total absence
of anterior avicularia. The present species may perhaps be
identical with S. ciliata, Aud. (sp.) (‘ Egypt,’ pl. xu, fig. 2),
but if so, the drawing does not exhibit the granular peri-
stome, nor the toothed, radical tube ; and moreover, in that
species the lowest marginal spine on the outside is represented
as forked.

Fam. 4. Caperetpa, Bk.
Gen. 4. Caberea, Bk.
1. C. Boryi, Audouin.

Thus adding another stage in the progress of this species
from the southern hemisphere towards the British Channel.

Fam. 5. Scruparip#, Bk.
Gen. 5. Seruparia, Oken.
1. §. diaphana,n. sp. Pl. XXXI, figs.1, la.

Polyzoario libero, suberecto, irregulariter ramoso; cellulis elongatis,
diaphanis, antice sparse perforatis ; orificio orbiculari, infra sinuato, peri-
stomate valde producto superne emarginato; ramis, cellule parle superiori uno
latere surgentibus.

Polyzoarium free, phytoid, sub-erect, irregularly branched ; cells elongate,
walls transparent, sparsely punctured in front; orifice orbicular, sinuated
below, peristome thin, produced, notched above; branches springing from
one side of cell at the top.

Hab.—Madeira, abundant, J. Y. J.

A beautiful and very distinct form. From the extreme trans-
parency of the walls, they appear at first sight asif they were
composed simply of a chitinous substance, but when incine-
rated, sufficient calcareous matter is left perfectly to retain
the form of the cell.

282 ZOOPHYTOLOGY.

From the peculiar delicacy of the walls this species would
afford perhaps the best subject yet met with for the study of
the living animal in the cheilostome Polyzoa.

Gen. 6. Avlea, Lamx.
1. 4. truncata, Bk.
Fam. 6. BiceLtaritp#, Bk.
Gen. 7. Bugula, Oken.
1. B. gracilis, Bk.
2. B. avicularia, Lk. (sp.)

Fam. 7. FLustRipxX.
Gen. 8. Carbasea, Gray.
1. C. ligulata,n. sp. Pl. XXXI, fig. 2.

Polyzoario phytoideo, erecto, ramoso, ramis trregularibus, ligulatis, graci-
libus, rectis, divaricatis ; cellulis, bt-triseriatis, elongalis, fusiformibus, sub-
cylindraceis, inferne attenuatis, clausis, poro centrali lunato, et duobus
minoribus simplicibus, infra orificium, ornatis, laterihus punctatis, dorso
glabro; orificio semicirculart, labio inferiori recto, superiori spinis margina-
libus sex munito ; ovicellulis, subglobosis erectis, superficie delicatule rugosis.

Polyzoarium phytoid, branched; branches irregular, very slender, straight,
divaricate; cells bi-triserial, elongated, fusiform, sub-cylindrical, tapering
downwards, closed in front, with a lunate pore in the centre, and two
smaller, round, simple pores immediately below the orifice; orifice semi-
circular, lower lip straight, upper margin furnished with six spines; ovicell
sub-globose, erect, finely wrinkled on the surface; cells smooth and rounded
behind.

Hab.—Madeira, J. Y. J.

This very peculiar and well-marked species is at once
distinguished from all its congeners by the habit of the
polyzoary, which is thoroughly phytoid, except that the
branches are all in one plane. At first sight it resembles a
fucus or sertularian zoophyte. On the sides of the branches
are frequently placed radical tubes, as in several others of
the Flustridee.

Fam, 8. MremMbBRANIPORID.U.

Gen. 9. Membranipora, Blanv.
1. M. Rosselii, Aud. (sp.)
22. M. Lacroivii, Aud. (sp.)

I am not quite sure that this form is rightly referred to
M. Lacroixii, but it so closely resembles that Mediterranean
species as to render their identity highly probably. Whether
this may be the case or not, there can, however, be no

ZOOPHYTOLOGY. 2838

doubt that the present form is the same as M. irregularis,
1D’ Orbigny (‘ Amer. Mérid.,’ pl. viii, figs. 5, 6), with which
may also, perhaps, be associated the same author’s M. simplex
(ib., figs. 7, 9). The cells are for the most part oval,
not contiguous, very irregular in size and position. The
margin is granular, and wholly unarmed, and there is no
appearance of avicularia in any part of the two or three
patches submitted to examination.

The following may be taken, I think, as the synonymy of
this protean species :

M. Lacroivii, Aud.; Bk.; Alder.
M. irregularis, M. simplex ? D’Orb.
Flustra distans, Hassall; Johnst.; W. Thompson (Belf.)

3. M. lineata, Linn. (sp.)
4. MM. Calpensis, Bk.

Gen. 10. Lepralia, Jolnst.
1. Armate.
a, With oral spines,

1. LZ. discoidea, Bk.

For a full account and corrected character of this species,
see Mr. Hincks’s observations, supra.

2. L. innominata, Jolnst.
3. L. radiata, Moll.

I have some doubts whether these two may not, strange
as it may seem, prove to be varieties of each other, in which
case Moll’s name will, of course, have precedence.

4. L. porcellana,n. sp. Pl. XXXI, fig. 3.

Cellulis latis, subrhomboideis, immersis, superficie rugosé, granulosd,
nitidd : orificio superne rotundato, infra coarctato, labio inferiori integro,
superiort spinis tribus, sepius absentibus, munito ; aviculario, mandibulo
trianguluri acuto superne et ad externuum spectante, utroque lateri cellule
posito.

Cells broad, ovate or rhomboidal, deeply immersed ; surface uneven,
bossed, granular, polished, porcellanous; orifice rounded above, contracted
below, with an entire lower lip, and three marginal spines above, often
absent or to be found only on the younger cells; a raised avicularium on
each side of the cell, about the middle; the mandible triangular acute, point-
ing upwards and outwards.

Hab.—Madcira, on shell, J. ¥. J.

The remarkably polished or porcellanous surface gives
the patches formed by this Lepralia so peculiar an aspect,

284 ZOOPHYTOLOGY.

that it may, by that character alone, be at once distinguished.
In the younger patches the surface is shining and glossy,
and, in this condition, the three marginal spines are usually
present; and the outline of the orifice is distinct and free.
Very soon, however, the walls appear to thicken, and to
become irregularly bossed, especially around the orifice,
which is thus lodged in a sort of irregular depression.

5. L. vulgaris, Moll.
6. L. marsupiata,n. sp. Pl. XXXT, fig. 4.

Cellulis ovatis, superficie granulosd, obscure punctatd ; orificio semi-
circulari, labio inferiori recto, integro, superiori spinis sex validis, articulatis
guarum infimis furcatis armato; ‘poro lunato medio infra orificitum rostro
poculiformi obtecto ; ad unum latus cellule vibraculo, setd nigra.

Cells ovate; surface granular, with scattered fine puncta; orifice semi-
circular or arched above, lower lip straight, entire; six large articulated
spines on the sides and above, the lowermost of which on either side is
forked at the extremities; a ]unate pore in the middle, a short distance
below the orifice, protected below and on the sides by a pouch-like rostrum ;
a long, slender vibraculum, with a black seta on one side of the cell, towards
the upper part.

Hab.—Madeira, on shell, J. ¥. J.

A very well-marked and beautiful species. The marginal
spines are distinctly articulated, as in L. Gatiye, Bk., and
one or two others, by a horny substance of a black colour.
They are consequently readily broken off.

7. L. Woodiana, Bk.

This agrees in all essential characters with L. Woodiana of
the Crag, and which has been found in the living state in
Treland by Mr. Hincks. The Madeiran specimens, however,
differ in some respects, and chiefly in the greater development
of the cup-like peristome, and the apparently larger size of
the avicularia on the shoulders of the cell. Another difference
also may be found in the apparent absence of the series of
marginal punctures observable in L. Woodiana. If it should
prove a distinct species, it will probably be found to coincide
with L. Dutertrei, Audown (sp.) ,

8. L. sceletos, Bk.
B. No oral spines.
L. unicornis, Johnst.
L. alba, Yincks.
11. Z. concinna, Bk.
2. Inarmate.

a. Without oral spines.
12. L. Mangnevilla, Aud, Pl. XXXI, fig. 5.

ZOOPHYTOLOGY. 285

Cellulis ovatis, superne liberis suberectis, crebré punctatis ; orificio superne
arcuato infra coarctato, peristomate producto, infundibuliformi in cellulis
sterilibus integro in fertilibus superne alte emarginato; ovicelluld parva,
recumbente, immersda.

Cells ovate, free and sub-erect above, surface uneven, punctured ; orifice
arched above, contracted towards the lower part, surrounded by a much
raised, infundibuliform or sub-tubulose peristome, which is entire in the
sterile and deeply emarginate above in the fertile cells; ovicell small,
recumbent, immersed.

Hab.—Madeira, J. Y. J.; Mediterranean, Savigny.

From a general resemblance to Savigny’s figure, I venture
to refer the present species to Audouin’s L. Mangnevilla; but
at the same time, since some doubt may be entertained on the
subject, I have thought it best to give a figure and diagnosis
of the Madeiran form.

In the figure, the surface is incorrectly represented more
as if it were granular than merely uneven and punctured.

(To be continued.)

ZOOPHYTOLOGY.

DESCRIPTION OF PLATES XXX & XXXI.

PLATE XXX.

Fig.

1.—Membranipora imbellis. (p. 275.)
2.—Lepralia armata. (p. 275.)

2 a.—Ovicell.

3, 3 a.—L. eximia. (p. 276.)

4.—I,. discoidea, x 25 diam. (p. 276.)
4a— 5, x 50 diam. (p. 276.)
5.—Cellepora tubigera? (p. 278.)
6.—Alecto incurvata. (p. 279.)
7.—Farrella dilatata. (p. 279.)

PLATE XXXI.
Fig.
l.—Scruparia diaphana. (p. 281.)
2.—Curbasea ligulata. (p. 282.)
3.—Lepralia porcellana. (p. 283.)
4.— ,, marsupiata. (p. 284.)
5.— 4, Mangnevilla? (p. 284.)

ZOOPEY TO, 0 GY.
Plate XXX.
ate ee

‘W. West. imp.

AVON LONM:OIG Ne

Plate

IN.DEX, TO

JOURNAL.

VORUNE: VWiit.

A.

Aberration, at acurved surface, Theory
of, demonstrated by H. M., 21.
Acephala, Vegetable Parasites in the
Shells of, 180.
Achnanthes, Bory, 120.
angustatus, Grev., 14, 20.
» costatus, C. Jolnst., 15.
Achnanthidium, Kiitz., 120.
Achromatic condenser, new one, by
Powell and Lealand, 106.
Actiniscus Sirius, Khr., 128.
Actinocyclus, Khr., 113.
ee areolatus, Brightw. (sp.),
93.

+ as

2”

spinosus, Brightw., 93.

% trilingulatus, Brightw.,93.
Actinophenia splendens, Shadbolt, 94.
Actinoptychus interpunctatus, Brightw.,

94,

Astea truncata, Bk., 282.

Alecto incurvata, Hincks, 279.
Alysidota conferta, Bk., 145.
Amphipleura, Kitz., 115.

pellucida, 25, 49, 50.
W. Hendry on

22

the lines in, 209.
Amphiprora, Khr., 115.
Amphora, Khr., 112.

Aneurisms, and LExtravasations of
Blood, caused by Parasites, 272.
Angle of Aperture, W. Hendry on, 61.
Annelida, Vegetable Parasites in the

Tubes of, 184.
Anthozoa, Vegetable Parasites in the
Hard Tissues of the, 178.
Aperture, Angular, P. Gray on, 135.
Arachnoidiscus Ehrenbergi, 18.
= japonicus, Khr., 14.
Archer, W., Description of Cosmarium
Portianum, 235.
» On some cases of abnormal
growth of Desmidiacee, 75, 234.

Archer, W. Description of two new
species of Staurastrum, 75.

» On the occurrence of Zoo-
sporesinthe family Desmidiacee, 215.

Arnott,G, A. Walker. On Cyclotella, 244.
rf 3 On certain ma-
rine objects collected at St. An-
drew’s, 141.

Arthrodesmus incus, 86, 234.

Asterionella, Hass., 122.

Asterolampra Marylandica, 94.

Asteromphalus centraster, C. Johnston,
12, 16.

Atmospheric corpuscles, M. Pouchet
on the means for the collection of
the, 188.

Aulacodiscus lavis, 95.

3 radiatus, Bailey (sp.), 95.
is sculptus, Sm. (sp.), 94.

B.
Bacillaria, Gm., 119.
a G., New Polyzoa, collected by,
23.

Baur, A. On Chitine, 264.

Beck, R. On the Universal Screw, 103.

Beryx ornatus, 171.

Bicellaria Alderi, Bk., 213.

Biddulphia, Gray, 121.

Bodo viridis, Khr., 227.

Bowerbank, J. 8. Note on Prof. Kolli-
ker’s Observations on the frequent
occurrence of Vegetable Parasites
in the Hard Tissues of the Lower
Animals, 187.

Brachiopoda, Vegetable Parasites in
the Shells of, 182.

Brightwell, T. On some of the Rarer
or undescribed Species of Diato-
macee, Part II, 93, 139.

Brown, H. Hort. Upon Microscopic
Manipulation, 152,

Bugula avicularia, Lamk., 282.

» gracilis, Bk., 282.

288 INDEX TO

C.

Caberea Boryi, Aud., 281.

Camera Lucida, Improvement of, P.
Gray on the, 137.

me an M. Nachet on the,
156.

Campylodiscus, Ehr., 113.

marginatus, C. John-

C. John-

ston, 13, 17.
5 productus,
ston, 12, 16.

Carbasea ligulata, Bk., 282.

Caspary. On the Zoospores of Chiroo-
lepus, 159.

Catenicella elegans, Bk., 280.

Cellepora armata, Hincks, 278.

5 tubigera, Bk., 278.

Cell-plate, microscopic, 153.

Cement, New, for mounting objects
for the Microscope, J. W. Law-
rance on a, 135.

Charleston, $. Carolina, The Micro-
scopic forms of the Harbour of,
A. M. Edwards on, 127.

Chitine, A. Baur on, 254.

Chroolepus, Ag., Caspary on the Zoo-
spores of, 159.

Chroolepus aureum, Spr., 159.

r umbrinum, Kg., 160.

Cirrhipedia, Vegetable Parasites in
the Shells of, 184.

Clark, J. Lockhart. Observations on
the structure of Nerve-fibre, 65.

Closterium, 224,

rH lunula, 89, 234,
Cocconeis, Ehr., 112.
by regina, C. Johnston, 13, 17.

Cocconema, Shr. 119

Collecting-bottle, Smith, James, on a,
204.

Colletonema, Bréb., 122.

Comber, Thos. On the Diatomacex
of the neighbourhood of Liverpool,

Compress, self-acting, 153.
Corpuscles, Atmospheric, in the Respi-
ratory Organs of Animals, M.
Pouchet on, 259.
, suspended in the Atmo-
sphere, Observations on the, 139.
Coscinodiscus, Bhr., 113.
rr centralis, 26.
‘ radiatus, 26.
Cosmarium, 223.
33 Portianum, W. Archer, 235.

Crustacea, W. C. Williamson,

JOURNAL,

Cosmarium, W. Archer, Description of
a new Species of, 235.
Craspedodiscus coronatus, Brightw., 95.

i marginatus, Brightw.
(sp.), 95.

> pyxidicula, Ehr., 95.

- semiplanus, Brightw.,95

Cristatella mucedo, Where to look for
and how to find, 59.

on
some Histological Features in the
Shells of, 35.

Crystals, J. Lobb On the rings round
the optic axes of, 107.

Cyclotella, Khr., 1138.
943 G. A. Walker-Arnott, on,

44.

5 Dallasiana, 245, 246.
» Kutzingiana, 245, 247.
a Meneghiana, 246.
i minutula, 245, 247.
i operculata, W.-Arn., 247.
3 radiata, Brightw., 96.
as rotula, W.-Arn., 247.
i stylorum, Brightw., 96.
Cymatopleura, Sm., 114.
Cymbella, Agardh, 112.

D.

De Bary, Anton. The Mycetozoa, a
contribution towards the knowledge
of the lowest animals, 97.

Denticula, Kitz., 120.

Desmidiacer, 77, 81.

.s W. Archer on some cases
of abnormal growth of, 85, 234.

3 ;, ontheoccurrence
of Zoospores in the Family, 215.

. A new genus and species
of, N. V. Dixon On, 75, 79.

Desmidie (Schizomerous), Synopsis
of, 84.

Diatoma, Decand., 121.

Diatomaceee, American,
Edwards on, 127.

- T. Brightwell On some
of the rarer or undescribed species
of, Part I, 93, 139.

a chiefly of those found in
« Elide” (Lower California) Guano,
Descriptions of, by Christopher
Johnston, 11.

+; of the neighbourhood of
Liverpool, Thos. Comber on the,
111.

Arthur M.

INDEX TO

Diatomacez, on the markings of, Thos.
G. Rylands, 25.

Diatom-finder, Robt. Taylor ona, 62.

Diatoms, J. D. Sollitt on the measure-
ment of the stric of, 48.

Dictyocha fibula, Ehr., 128.

Dixon, N. V. Ona new genus and
species of Desmidiacee, 75.

Docidium Ehrenhergii, 227.

Bs clavatum, 91.
Doryphora, Kiitz., 119,

E

Edwards, A, M. On American Diato-
maceer, 127.

Elevations and Depressions under the
Microscope, Welcker, H., on the
Distinguishing of, 52.

Encyonema, Kiitzing, 122.

Epithemia, Kiitz., 112.

Kuastrum didelta, 87.

is insigne, 87.

Lucampia, Elr., 120.

Funotia, Ehr., 112.

Lupleuria incurvata, Arnott, 21.

Eupodiscus, Ehr., 113.

argus, 27.

radiatus, Sm,, 129.

i.

Farrella dilatata, Hincks, 279.

Ferments, L. Pasteur on the origin
of, 255.

Finder, The Nose-piece, H. U. Jan-
son on the, 271.

Fish, Vegetable
scales of, 184.

Flustra Barleei, Bk., 123.

Fragillaria, Lyngb., 120.

G.

Gasteropoda, Vegetable Parasites in
the Shells of, 183.
Gephyria, Arnott, 20.
incurvata, W.-Arnott, 18.
media, Arnott, 20.
a Telfairia, Arnott, 20.
Gleocapsa, 92.
Gomphonema, Agardh, 119.
Grammatophora, Whr., 121
Gray,P., On Angular Aperture, 135.
Greene, J. R. Manual of the Sub-
kingdom Protozoa, notice of, 192.
Guano,“ Elide,” Descriptions of Diato-
maces in, 11.

39

2”

Parasites in the

2

39

JOURNAL. 289

Pee

Harrison. On Preurosigma Parkerii,
105.
Feliopelta Phaeton, C. Johnst., 13, 18.
Hendry, W. On Angle of Aperture,
61.
a On the Lines in Amphi-
pleura pellucida, 209.
* On a Saccharo-Polari-
scope, 248.
Hicks, J. B. On the development of
the gonidia of Lichens, 239.
Himantidium, Ehr., 120.
Hincks, T. Description of new Polyzoa
from Ireland, 275.
Holocystis oscitans, Hassall, 79.
Homeocladia, Agardh, 122.
Houghton, W. Where to look for and
how to find Cristatella mucedo, 59.
Huxley, T. H. On the structure of
the Mouth and Pharynx of the
Scorpion, 250.
Hyalodiscus cervinus, Brightw., 95.
Hyas araneus, 40, 41, 43.
ir

Illuminator, Dark-ground, M. Nachet
on a, 207.

3 Oblique-light, M. Nachet
on an, 208.

Injections, W ‘Turner on the employ-
ment of Transparent, in the exami-
nation of the Human Pancreas, 147.

Injecting Fluid, Blue, B. W. Richard-
son on an, 271.

J.

Janson, H. U. On an Object-Finder,
198, 271.

Johnston, Christopher. Descriptions
of Diatomacee in “ EHlide” Guano.

K.

Kolliker, A. On the frequent occur-
rence of Vegetable Parasites in the
Hard Tissues of the Lower Animals,
Ivor -

Lawrance, J. W., On a new Cement
for Mounting Objects for the Micro-
scope, 135.

Lepralia alba, Hineks, 275.

» Barleei, Bk., 143.

» bella, Bk., 144.

» eanthariformis, Bk., 143.
» discoidea, Bk., 144, 276.

290 INDEX TO JOURNAL.

Lepralia eximia, Hincks, 276. Morren. On Closterium, 224.
» Landsborovii, Johnst., 144,; Mounting Board, 152.
277. ; Mycetozoa, The, a contribution to-
» Malusii, Aud., 125. wards the knowledge of the lowest
» Manguevilla, Aud., 284. animals, by Anton De Bary, 97.
» marsupiata, Bk., 284, N
‘ don, Bk., 2138. x ‘
» Niall dr Bk., 283. Nachet, M. Onthe Camera lucida, 156.
> stauosa, Bk., 125. 2? On a Dark-ground Iilu-
3, wmbonata, Bk., 143. minator, 207. , ;
» vulgaris, Moll, 284. % On an Erecting Prism,
» Woodiana, Bk., 276. 206. 7.
Leuckart, Rud. On the mature con- ” On an Oblique-light Hla-

dition of Zrichi alike. minator, 208. ;
mactere I ; eh ote Develop- Nature - printed British Seaweeds.
ment of the gonidia of, 239. By W. G. Johnstone and A. Croall.
» W. Lauder Lindsay on the _Review of, 56.
Spermogones and Pycnides of, Notice Navicula, Bory, 115.

of, 194. is maculata, Kdw. (sp.), 128.
Lister, Joseph. Observations on the » permagna, Edw. (sp.), 128.
structure of Nerve-fibres, 29, 32. >” rhomboidea, 49.

Lobb, J. Ona method of showing the} » sigma, Bhr., 128.
rings round the optic axes of Crys-| Nerve-fibre, J. Lockhart Clarke on

tals, 107. _ the structure of, 65.
ax | Nerve-fibres, Joseph Lister, Observa-
M. tions on the structure of, 29, 32.
Manipulation, H. Hort Brown upon 3 W. Turner, Further ob-
Microscopic, 152. servations on the structure of, 150.
iMag Eivaltes tee. ee E. ee “ : new =
Melosira, Agardh, 121. or the exhibition of the axis cylin-
Membranipora Calpensis, Bk., 283.. ders in, 273. -
mS cornigera, Bk., 124. Nitzchia, Hassall, 114.
s imbellis, Hincks, 275. 4 signoidea, 48.
3 Lacroixii, Aud., 282. O.
» — Uineata, Linn, 283. | Object Cabinet, James Smith, Deserip-
a minax, Bk., 125. i f 901
Rosselii, Aud., 282. pei pee Se
» y ? Object-finder, H. U. Janson On an, 198.

% vulnerata, Bk., 124. Obi ede =
ae ject-glasses of high powers, J.
Meridion, Agardh, 119. Mitchell On, 273. 5

Micrasterias Jenneri, W. Archer on a Odenivioun, Nate to

Se ee Orthosira, Thwaites, 121.
¥ pinnalifida, Ralfs, 79, ” oceanica, Ehr. (sp.), 96.
Micrography, Atmospheric, M. Pou- ,
chet on, 130, 188. Pancreas, W. Turner on the Em-
Microscopical Society, Proceedings of:| ployment of Transparent Injections
June 29th, 1859, 63. in the examination of the minute
Nov. 9th, 1859, 106. structure of, 147.
Jan. 11th, 1860, 140. Parasites, On Aneurisms and Extra-
Feb. 8th, 1860, 141. vasations of Blood caused by, 272.
March 14th, 1860, 142. » Vegetable, in the Hard Tis-
April 11th, 1860, 210. : sues of the Lower Animals, A. Kol-
May 9th, 1860, 210. liker on the frequent occurrence
June 13th, 1860, 210. OF, 7a

Mitchell, J. On Object-glasses of| Pasteur, L. On the origin of Fer-
high power, 273. ments, 255,

INDEX TO

Pediastrum, 217.

Penium Cylindrus, 92.

Pfluger, On a New Reagent for
the exhibition of the Axis Cylinders
in Nerves, 273.

Pilumnus hirtellus, 41.

Pinnularia, Ehy., 116.

Pleurosigna, Sm., 117.

angulatum, 26.

balticum, 25.

Jusciola, 48.

Muakron, C. Johnst.,

bE]

15,
18.
” Parker it, 105.
strigosum, 48.
Podosira, Ehr., 121.
Portumnus depurator, 41, 42, 44.
Polarizing Stage, Smith, J., on a, 203.
Polythalamia, Vegetable Parasites in,
176.
Polyzoa, T. Hincks, Description of
New, from Ireland, 275.
» collected by J. Yate Johnson,
Esq., at Madeira, Catalogue of, 280.
Shetland, 213.

New species of, collected in
Shetland, by G. Barlee, 123, 143.
Pouchet, M. ‘On Atmospheric Micro-

graphy, 130.

Ps On Atmospheric Corpus-
cles in the Respiratory Organs of
Animals, 259.

a On the means by which
all the Corpuscles normally invisible,
contained in a determinate volume
of air, may be collected into au in-
finitely small space, 188.

Prism, erecting, M. Nachet on an, 206.
Protozoa, Notice of Prof. Greene’s
Manual of the Su! Kingdom, 192.
Pustulopora orcadensis, Bk, 214.

Pythium extophytum, 231.
R

”

Rainey, Geo. On the structure and
mode of formation of Starch-gra-
nules, 1.

Registration of Objects, G. L. Wal-
lich on the, 136.

Rhabdonema, Kiitz., 121.

Rhipidophora, Kiitz., Jey

Richardson, B. Wills. On a Blue In-
jecting Fluid, 271.

S.

Saccharo-Polariscope, W. Hendry on
a, 248.

JOURNAL. 291

Salicornaria Johnsont, Bk., 280.

Sarcina, and especially on its occur-
rence in the Urine, H. Welcker
on, 163.

Schizonema, Agardh, 122.

Scorpion, T. H. Huxley on the struc-
ture of the Mouth and Pharynx of
the, 250.

Screw, universal, R. Beck on the, 103.

Seruparia diaphana, Bk., 281.

Serupocellaria Macandrei, Bk., 281.

me Maderensis, Bk., 280.

Seaweeds, Nature-printed, by W. G.
Johnstone and A. Croall, notice of,
193.

Smith, James. On a Collecting Bottle,
204.

Description of an Ob-
ject Cabinet, 201.
e On a Polarizing Stage,
203.

Sollitt, J. D. On the measurement of
the striz of Diatoms, 48.

Spatangidum Ralfsianum, Grev., 16,
28.

Sponges, Vegetable Parasites in, 173,
187.

Stand, microscopic, and mountingappa-
ratus, 155.

Starch-granules, Rainey, G., on the
eee and mode of formation
of ak

Staurastrum dejectum, 86.

Description of two new
species, by W. Archer, 75.

nitidum, W. A., 78.

oxyacantha, W. AL, Wi

Staur ones, Doty UWE

angulata, C Johns., 13, 18.

BB

33

| Stephanogonia polygona, Vhr., 96,

Striatella, Agardh, 121.
Surirvella, Turp., 113.
Synedra, Ehr., 118.

a

Tabellaria, Ehr., 121.
Taylor, Robt. On a Diatom-finder,

62.
Tetmemorus Brébissonii, 87.
Tetrachastrum, Dixon, 81.
mucronatum, Dixon, 82,
oscitans, Dixon (sp.),

2?

32
83.

“5 pinnatifidum, Dixon

(sp.), 83.

292 INDEX TO

Toxonidea, Donkin, 118.

Triceratium, Ehr., 113.

Fuvus, 26.

. Jimbriatum, 27.

Trichina spiralis, Rudolph Leuckari
on the mature condition of, 168.

Trichocephalus dispar, 168.

Tryblronella, Sm., 114.

Turner, Wm. On the Employment of
‘Transparent Injections in the exa-
mination of the minute structure of
the Human Pancreas, 147.

4 Further observations on
the structure of Nerve-fibres, 150.

W.
Waldenberg, LL. On Aneurisms, and

”

JOURNAL.

Wallich,G.L. On registration of ob-
jecis, 136.

Welcker, H. On the Distinguishing
of Elevations and Depressions un-
der the Microscope, 52.

y; On Sarcina, and espe-
cially on its occurrence in the urine
of man, 163.

Williamson, W.C. On some Histo-
logical Features in the shells of the
Crustacea, 35.

X.
Xanthidium, 238.
Smithii, W. Arch., 238.

Z.
Zoophytology, 123, 1438, 213, 275.

oP

extravasations of Blood, caused by |
Parasites, 272. |

PRINTED BY J,

E.

Zoospores, W. Archer on the occur-
rence of, in the Desmidiaces, 215.

ADLARD, BARTHOLOMEW CLOSE,

IWIN.

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JOURNAL OF MICROSCOPICAL SCIENCE.

DESCRIPTION OF PLATE I,

Illustrating Mr. Rainey’s paper on the Formation of the
Starch-granule.
Fig.

1.—Ordinary forms of starch.

2, 3.—Starch-granules; two joined together, producing an appearance
considered to be the result of cell-multiplication by division.

4.—Three starch-granules similarly united.

5.—Three granules thus united, as seen by polarized light, from Criiger.

6, 7.—Starch-granules, called by author “compound granules.”

8.—Two globules of carbonate of lime, joined together and coalescing into
one ; from calcifying shell of oyster.

9.—Large artificial calculi of carbonate of lime in progress of coalescence.

PLATE I (continued),

Tllustrating Dr. C. Johnston’s paper on Diatomacez,
chiefly from Elide.

10.—<Asteromphalus centraster, C. J.
a. Portion of the same, more highly magnified.
11.—Campylodiscus marginalis, C. J.
12.—Cocconeis regina, C. J.
13.—Achnanthes angustata, C. J.
14.— 7 costatus, C. J.
a. Upper valve. 4. Lower valve, side view. . Front view of frustule.

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JOURNAL OF MICROSCOPICAL SCIENCE.

DESCRIPTION OF PLATE II,

Illustrating Messrs. Lister and Turner’s paper on the
Structure of Nerve-fibres.

Fig.

1.—Represents part of a transverse section of the sciatic nerve of a cat
hardened by chromic acid, and tinted with carmine; the axial cylinder
alone having received the colouring matter. The specimen was
dried and viewed as an opaque object.

2.—Shows the appearance of thin transverse sections of some nerve-fibres
from the same nerve, simply hardened in chromic acid, and ex-
amined moist by reflected light. The axial cylinder has, under this
low magnifying power, the aspect of a mere space.

3.—Similar objects to those of fig. 2, but seen by transmitted light.

4.—A highiy magnified transverse section of a nerve-fibre from the same
source, prepared like those of figs. 2 and 3, and then tinted with
carmine. ‘The carmine colour is seen to affect only the axial
cylinder and the investing membrane, which, at one part, is torn up
from the fibre. This abetch also shows the faintly granular structure
of the axial cylinder, and the irregularly concentric striation of the
medullary sheath.

5.—A transverse section of a columnar portion of the spinal cord of a cat,
also prepared with chromic acid and carmine, and examined moist by
transmitted light. The fibres vary much in size, but all of them
resemble those of the sciatic nerve in having the red axial he
surrounded by a ring of untinted medullary sheath.

6—10 are highly magnified views of some fibres in a section of the cord
like that of fig. 5. They present the same characters as thie fibres of
the sciatic nerve.

11.—A fibre from a longitudinal section of a columnar portion of the cord,
prepared in the same way. The axial cylinder alone is carmine
coloured, and is, in some parts, stripped of its investing sheath, the
fibroid arrangement of which is also displayed.

12.—A small fibre under similar circumstances.

13.—Fatty matter in a state of arborescent fibroid aggregation.

JOURNAL OF MICROSCOPICAL SCIENCE,

DESCRIPTION OF PLATE III,

Illustrating Professor Williamson’s paper on the Structure of
Crustacean Integuments.
Fig.
1.—Diagrams of the layers in the shell of a crab.
2.—Grouped tubuli from above, areolar layer of common crab.
3.—Areolar layer, showing the very delicate areolz in the shrimp.
4.—One of the calcified discs from the carapace of a shrimp, formed at the
base of a short tubular hair.
5, 6.—Dises from the same after further calcification; in fig. 5 is seen a
translucent crucial figure.
7.—Disc from the same in a less consolidated state.
8.—Detached granules from a similar disc.
9, 10.—Appearance of areolar layer in a shrimp after boiling with caustic
potass.
11.—Vertical section, carapace of Pilumnus hirtellus.
12.—-Horizontal section of the same, decalcified, as seen from above.
13.—Vertical section, crayfish.
14.—Horizontal section, lobster, immediately beneath the areolar layer.
15.—Vertical section of the same.
16.—Vertical section, claw of hermit-crab.
17.—Derm or “‘enderon,” soft portion of integument of hermit-crab.
18.—The same, from above.
19.—Section of botryoidal concretionary masses from a small Australian
crab.

The same letters are used to similar parts throughout.

a. Pellicular layer. g. “Derm” of soft carapace.
6. Areolar layer. h. Its cells and nuclei.

d. Corium calcified. t. Its pigment-cells.

e. Tubuli. &. Basement membrane.

J. Uncalcified corium.
In fig. 17, 4 indicates the corium and areolar layers blended.

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JOURNAL OF MICROSCOPICAL SCIENCE.

DESCRIPTION OF PLATE IV,

Illustrating Mr, Clarke’s paper on Nerve-structure.

Fig.

1.—Represents an elevation or ridge of the white substance on the surface
of a primitive nerve-fibre.

2.—A double-contoured primitive-fibre, hardened in chromic acid, and mag-
nified 670 diameters.

3.—A similar fibre treated in the same way, but with its outer corrugated
surface more or less broken.

4 & 5.—Two detached portions of a fibre, hardened in chromic acid,
showing how the angular bendings give rise to the appearance of
fibres or tubules.

6.—An uninjured double-contoured primitive-fibre, examined immediately
after death; a, axis-cylinder; 4, outer contour; c, inner contour;
d, membranous sheath bearing an elongated nucleus.

7 to 10.—Represent fresh primitive-fibres, more or less injured by mani-
pulation.

11 to 16.—Represent the white substance of Schwann, between the
double contour, after injury by manipulation. At fig. 14 it appears
twisted in some places into a kind of knot; while in other places it
is simply affected by indentations of various lengths and breadths,
which are represented by the dark spaces, the light spaces having
the appearance of fibres.

17 to 20.—Represent perfectly fresh primitive-fibres, stretched and other-
wise injured in manipulation, by which the white substance has been
thrown into variously-shaped convolutions, ridges, or apparent fibres

21.—Represents free globular contents escaped from the nerve-fibres.

22 and 23.—Two fresh nerve-fibres thrown into ridges of various shapes
and sizes, under the influence of strong acetic acid. In fig. 23, on
the surface of the fibre, are two or three spiral ridges similar to the
spirals seen at the cut end of fibres hardened in chromic acid.

24.—a, free nuclei from the connective tissue and sheaths of the nerve-
fibres in the white columns of the spinal cord ; 4, nucleated cells from
the same parts in the calf; c, cut ends of two primitive nerve-fibres,
hardened in chromic acid, and presenting the appearance of spiral
fibres. The angular interspace between them is occupied by a
nucleated cell.

JOURNAL OF MICROSCOPICAL SCIENCE.

DESCRIPTION OF PLATES V, VI,

Illustrating Mr. Brightwell’s paper on New or Imperfectly-
known Diatomacez.

PLATE V.
Fig.
1.—Actinocyclus areolatus ; a, side view; 4, front view in outline. .
2.—Actinocyclus, side view; a, front view; 4, the same of two pustules
undergoing self-division, both in outline; these two figures from
drawings by Mr. F. Kitton.
3.—Asterolampra Marylandica, Khr., specimen with six segments.
4.—Craspedodiscus pyxidicula, Khr. :
5.—Aulacodiscus sculptus, front view.
6.—Craspedodiscus, nv. sp., fragment of a valve.
7.— = » side view.
8.—Stephanogonia polygona, Khr.; a, side view; J, front view.
9.—Hyalodiscus.
10.—Awlacodiscus radiatus, Bailey ; a, side view; 4, front view.

PLATE V1.

11.—Cyelotella, n. sp.; a, side view; 4, front view of short filament.

12.—Craspedodiscus, n. sp.

13.—Aulacodiscus, abnormal specimen.

_ 14.—Orthosira oceanic; a, side view; 6, front view of pustule and single
valve adherent.

15.—Actinocyclus, n. sp.

16.—Cyclotella, n. sp.; a, side view; 4, front view.

17.—Lupodiscus.

18.—Actinophenia splendens, Shadb., showing both coarse and fine markings.

All magnified 400 diameters.

For Description of Plate VII, illustrating Mr. Archer’s paper
on Desmidiacez, see Paper.

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JOURNAL OF MICROSCOPICAL SCIENCE.

DESCRIPTION OF PLATE X,

Illustrating Dr. J. Braxton Hicks’s paper on Contributions
to Development of the Gonidia of Lichens, in relation
to the Unicellular Algze, &e.

Fig.
1.—Chlorococcus.
a, ad. Mature, quiescent cell.
b, 6. Segmentation, radiating from centre.
c, c. Advanced condition of same.
d, d. Binary and quaternary subdivision.
e. Quaternary subdivision, reverting to mature stage.
2.—Chlorococcus in various stages.
a. First appearance of growth of fibre.
b, 6, 6. More advanced condition.

3.—Mature, quiescent gonidium.

4.—Formation of soridium.

5.— a Fe segmentation proceeding at same time with

fibre-growth.
6.—Oval cells, the result of segmentation going cn to binary sub-
division.
7.—Soridium of Chlorococcus, and also of Lichen.
$.—Contents of a soridium pressed apart.
9.—Single, dormant soridium (section of).
10.—Soridium in which segmentation has proceeded a certain distauce
and become dormant (section of).
a. Segments, numerous.
6, 6. Globular form of subdivisions.
11.—Active bodies in cavities in the fibres.

Figs. 1 to 4 illustrate Mr. Turner’s paper on the Minute
Structure of the Pancreas, and on the Axis-cylinder of
Nerves.

Fig.

1.—Portion of injected pancreas under a low power.

2.—Part of the same, with a much higher power.

3.—Lobules detached in course of preparation from a portion of pancreas
into which the injection has not entered, showing the globular epi-
thelium with which they are filled.

4. Portions of nerves in which the axis-cylinder has become coloured by
carmine, the sheath remaining quite free from colour.

JOURNAL OF MICROSCOPICAL SCIENCE.

DESCRIPTION OF PLATES XI & XII.

PLATE XI,
Illustrating Mr. Archer’s paper on the Occurrence of
Zoospores in the Family Desmidiacez.
Fig.
1, 2, 3, 4.—Docidium Ehrenbergii, with lateral projections in different stages
of development.

5.—Parasitic growth (Pythium) upon Closterium lunula.
6.—Mycelioid growth within Closterium luaula, R.
7.—Arthrodesmus Incus.

8.—Cosmarium Portianum ; front view.

9.— Ls $5 end view.
10.—Xanthidium Smithii ; front view.
11.— = an side view.
12.— 3 be end view.

PLATE XII,

Illustrating Professor Huxley’s paper on the Structure of
the Mouth and Pharynx of the Scorpion.

Fig.

1.—Longitudinal vertical section of the ceplalo-thorax of a Scorpion, show-
ing the pharynx, cesophagus, nervous centres, and the large eyes, in
their natural relations.

2.—Dorsal view of the cephalo-thorax of a Scorpion, opened and dissected,
so as to show the apodemata, and the anterior portion of the ali-
mentary canal, with the pharyngeal muscles.

3.—The chitinous lining of the anterior part of the alimentary canal, the
integument of the labrum, and the basal processes of the first maxilla.

4.—Thie chitinous lining of the pharyngeal sac, viewed from above.
5.—A transverse section of tle same, taken along the line z y (fig. 3).

6.—The region of the pharyngeal sac near the commencement of the
cesophagus.

The letters have the same significations throughout :—a, mouth; 4, labrum;
c, pharynx; d, esophagus; e, salivary duct; /, diaphragm; gy, eye @
and ocular nerve ; 4, subcesophageal ganglion; 7, antenna; &, maxilla; —
Z, mandible; m, apodeme; xz, pharyngeal muscles ; 0, sub-oral trans-
verse thickening of the chitinous integument; p, valve (?) of the
pharynx ; x y, line along which the section in fig. 5 is taken.

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