162 DR. T. $. COBBOLD ON ENTOZOA. 
It requires considerable enlargement and a good lens to render the comparatively large 
size of the hooks obvious, and the articulations of the body are but very faintly indicated 
toward the anterior part of the animal. Notwithstanding the fish in question had been 
dead several days and cast aside as refuse by the salesman of whom it was purchased, the 
Entozoa coiled within the muscles were alive, and on being removed to a tumbler of sea- 
water, they continued to live until the third day following, when they were placed in 
spirit. During the active movement of contraction and elongation, the proboseidiform 
tentacula were freely protruded and withdrawn. It was difficult to ascertain the exact 
number of hooklets upon these processes. I think every circular row carries sixteen, and 
there are about one hundred of these rings of hooklets on each proboscis; if this estimate 
be correct, the total number of hooklets is 6400. The form of the proboscis is clavate, 
and its free extremity more or less rounded; in relative size the hooklets are tolerably 
uniform, those towards the tip being rather larger; the two lowermost rows of the series 
are very highly developed. 
Acipenser sturio.—On the 25th of April, 1855, I obtained a great many examples of 
Dachnitis sphærocephala of Dujardin (Pl. XXXIII. fig. 51) and Distoma hispidum (Abild- 
gaard) from the spiral intestine. Contrary to the statements of Creplin, I find the hooks 
surrounding the head of the latter remarkably conspicuous and disposed in two rows, 
fourteen in each. I think it would be preferable to place this species in the subgenus 
Echinostoma. (Pl. XXXII. figs. 47, 48; Pl. XXXIII. figs. 49, 50.) Dujardin retained 
it among the true Distomata with hesitation. The integumentary spines in front are 
prominent, and directed outwards with a slight inclination backwards; those below the . 
ventral sucker become gradually smaller, and finally degenerate into mere tubercles at 
the posterior extremity. 
Rana temporaria.—From different individuals I have obtained Filaria rubella(?), Ascaris 
nigro-venosa, A. acuminata, Oxyuris ornata, Distoma cylindraceum, D. clavigerum (figs. 
52, 53), and Polystoma integerrimum, the latter being fully half an inch in length*. 
Bufo vulgaris.—With reference to parasites, I have only examined one or two examples 
of the common Toad, and in the intestine of an individual dissected on the 20th of 
April, 1855, found a single specimen of Ascaris acuminata associated with numerous 
small flukes. These trematodes are fully as large as the Distoma cygnoides, frequently 
infesting the urinary bladder of the Frog; nevertheless they may probably be referred to 
a smaller species—the D. clavigerum of Rudolphi, their length varying from one to two 
lines and a half. The vitelline ducts, the uterine canal with its crowded ova, and the long 
intromittent organ, are readily distinguishable in preserved specimens. 
Lissotriton punctatus.—I here wish to call attention to a striking illustration of the 
predilection for a particular species which certain Entozoa exhibit in selecting their habi- 
tation. A careful dissection of some thirty or forty Water-newts—consisting of our two 
most common species, the large black and the lesser speckled Salamanders in nearly 
equal proportions—has shown, that while in almost every instance worms were present . 
* The anatomy and development of these and other forms of Frog’s flukes have recently been illustrated by — 
Dr. H. Å. Pagenstecher in his attractive monograph, entitled * Trematodenlarven und Trematoden,” Heidelberg, 1857- 
Also in Dr. Wagener's “ Entwickelungsgeschichte von Distoma cygnoides.” 
