DR. T. S. COBBOLD ON ENTOZOA. 163 
in Lissotriton punctatus, not a single entozoon of any kind could be obtained from 
Triton cristatus; a fact rendered more significant inasmuch as the specimens were all 
obtained from the same locality, namely from ponds at the summit of the Braid Hills 
near Edinburgh. In the stomach of one of the large species there was a small trematode- 
like body, but on microscopie examination it proved to be a young horse-leech. From 
specimens of the lesser Newt, procured at intervals during the months òf April, May and 
June, 1855, there were obtained in the first place numerous examples of Ascaris acumi- 
nata, the presence of which was by no means invariable; secondly, an abundance of 
Echinorhynchus anthuris; thirdly, multitudes of Opalina intestinalis, a ciliated infusorial 
animalcule believed by Agassiz to be in reality only a larval planarian; and fourthly, a 
' considerable number of Trichodine. The first three groups were found in the stomach 
and duodenal portion of the intestinal canal; the fourth occupying the cloaca and ducts 
in its immediate neighbourhood. The only remark I have to offer respecting Ascaris 
acuminata has reference to its size, which is variously estimated by different authors ; 
my specimens average about 8 lines in length, which accords with Mr. Bellingham’s 
statement in his Catalogue of Irish Entozoa. This leads me further to observe, concern- 
ing the definition of species, that much unnecessary stress is laid upon the relative size of 
individuals, bulk alone, it would appear, being frequently regarded as a criterion of spe- 
cific distinction. In very many instances at any rate it cannot be denied that this is the 
case. I believe the error is so prevalent in the older lists, that for every new species 
now added, two old ones might with propriety be expunged. In the present communica- 
tion, it is not my intention to show how the truth of this assertion may be sustained by 
an appeal to facts; nevertheless, if it were desired, sufficient illustration might be afforded 
from the materials in hand. The second group, represented by Echinorhynchus anthuris 
(figs. 54-62 inclusive), deserves attention, forming as that species does, on account of its small 
size and extreme transparency, an excellent subject for microscopic investigation; but a 
minute description is not needed, in consequence of the admirable manner in which it was 
originally described by its discoverer, M. Dujardin. General details being given in the de- 
scription of the figures, attention in this place is only invited to a brief notice of the peculiar 
ova. These characteristic bodies in their early state are perfectly round, appearing simply 
as nucleated cellules in the interior of the so-called ovaries, which are also spherical, and 
float loose in the cavity of the body; the nucleus may be taken to represent the germinal 
vesicle, but it cannot be recognized in the fully developed ovum. In this latter condition 
each ovum encloses a perfectly transparent cell, lobed at both ends after the fashion 
of Trichina, and an irregular but very distinctly granular yelk-like mass; these are 
placed side by side; and from the granular body proceeds at either end a coiled 
thread or chalaza advancing to the extremity of the external envelope and vegeta 
blended with it; the wall of the transparent cell exhibits in profile very delicate E 
dulations. In regard to the infusorial Trichodinæ, which may yet m out to be cedi 
forms of some higher group, I have only to observe that some were in the encysted con- 
dition. - 
 Bothrops.—For an opportunity of dissecting å species of this genus Iam — to 
Mr. Edwards, Demonstrator of Anatomy in the University of Edinburgh. € - 
VOL. XXII. 
