CLAPAREDE, ON 'TREMATODA, ETC. 95 
which were kept in continued motion backwards and forwards, 
and they also gave off branches which went to form a net- 
work in the anterior and lateral parts of the body. The calca- 
reous corpuscles were lodged in these branches, and were not 
unfrequently pushed into the lateral trunks. No ciliary move- 
ment could be perceived in the vessels. In this case there- 
fore no doubt can be entertained that the corpuscles are 
lodged in the excretory system, and that the arrangement is 
precisely lke that which is witnessed in the Holostomata 
with a plexiform disposition of the calcareous corpuscles ; as, 
for instance, in Holostomum cuticola. The calcareous cor- 
puscles exhibited great diversity of aspect. Some were per- 
fectly homogeneous ; others presented a distinct concentric 
structure; whilst others again consisted in reality of several 
corpuscles united by a common enveloping calcareous layer. 
There were sometimes noticed in the lateral trunks, cell-like 
bodies, enclosing calcareous corpuscles and minute particles. 
With respect to the chemical composition of the so-termed 
calcareous corpuscles of the Trematoda and Cestoda we at 
present possess very insufficient information. In Echinococcus 
veterinorum, Huxley* asserts that they consist at first of an 
albuminous substance, but that they may afterwards become 
cretified ; a statement which is disputed by Leuckart.t I 
should not be disposed at once to reject Huxley’s view, seeing 
that the chemical composition of the corpuscles differs im 
different species, and it is very possible that it may vary 
according to circumstances In one and the same species. At 
any rate, the organic substance which serves as a matrix to the 
inorganic constituent, greatly predominates. The corpuscles 
in Diplostomum rachieum, volvens, and clavatum appear at 
first sight to be dissolved by caustic potass. This appearance, 
however, depends simply upon the circumstance that they 
are rendered transparent by that reagent, the transparency 
gradually advancing from the periphery towards the centre; 
the refractive power of the corpuscles is considerably increased, 
but in other respects they remain as before. This change 
obviously depends upon the solution of the organic matrix 
by the potass. The incrusting matter In some animals is 
always carbonate of lime, as for instance in Diplostomum 
rachieum, Echinococcus veterinorum, Trienophorus nodulosus, 
&c.; but in others, as in Diplostomum volvens and clavatum, 
I have been unable to detect any carbonate of lime in the 
corpuscles, which in these cases are dissolved in acids without 
effervescence. It is possible that in these instances the 
* «Annals and Magazine of Nat. Hist.,’ 2d series, vol. xiv, p. 381. 
+ ‘Die Blasenbandwiirmer.’ Giessen, 1856. 
VOL. VII. K 
