162 DR. T. S. 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 coUed witliin 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 

 spii'it. Dm-mg the active movement of contraction and elongation, the proboscidiform 

 t«ntacula were freely protruded and withdrawn. It was difficult to ascertain the exact 

 number of booklets upon these processes. I think every circular row carries sixteen, and 

 there are about one hundred of these rings of booklets on each proboscis ; if this estimate 

 be correct, the total nimiber of booklets is 6400. The form of the proboscis is clavate, 

 and its free extremity more or less rounded ; in relative size the booklets 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 sphcerocephala of Dujardin (PI. XXXIII. fig. 51) and Bistoma hispidum (Abild- 

 gaard) from the spiral intestine. Contrary to the statements of CrepUn, I find the hooks 

 surrounding the head of the latter remarkably conspicuous and disposed in two rows, 

 fom-teen in each. I think it would be preferable to place this species in the subgenus 

 Echimstoma. (PL XXXII. figs, 47, 48 ; PI. 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 Folystoma integerrwmm, the latter being fully half an inch in length*. 



Bitfo 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 niunerous 

 small flukes. These trematodes are fully as large as the Bistoma cygnoides, frequently 

 infesting the urinary bladder of the Frog ; nevertheless they may probably be referred to 

 a smaller species — the B. 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. A. Pagenstecher in his attractive monograph, entitled " Trematodenlarven und Trematoden," Heidelberg, 1857. 

 Also in Dr. M'agener's " Entwickelungsgeschichte von Distoma cygnoides." 



