160 DR. T. S. COBBOLD ON ENTOZOA. 



above mentioned cannot, so far as I know, be satisfactorily referred to any species of 

 Ascaris or other nematode at present described; and although unwilling to multiply 

 species in a group of Entozoa abeady extended numerically far beyond the proper limits, 

 there is in the present instance no alternative. Ascaris acanthocmi'data (mihi) may be 

 identified as follows : — Body 10 to 15 lines long, half a line broad ; diameter slightly 

 increased toward the head, suddenly narrowed at the tail ; mouth trilobular ; caudal 

 extremity armed with several minute spines (figs. 24-26). A preserved specimen in my 

 collection exhibits the transverse and longitudinal muscular layers with unusual clearness ; 

 but the most interesting structure, which can be seen with a half-inch lens, and its minute 

 tissues with a quarter-inch objective, consists of a broad double band of partially disin- 

 tegrated cellules, extending from head to tail on the under side of the body. The centre 

 of this band is occupied by a well-defined canal apparently containing a delicate white 

 thread. It does not give off any branches, but terminates superiorly in an abrupt manner 

 immediately below the trilobular mouth. From this point there is a faint appearance 

 of radiating lines towards the margin of the lobes, but I cannot positively say that they 

 are nervous filaments. Notwithstanding this doubt, I am confident that the long-enter- 

 tained opinions of Otto and Siebold, in regard to the existence of a nervous cord in the 

 Nematoidea, are correct. 



Sippoglossus vulgaris. — A specimen dissected on the 4th of May, 1854, yielded two 

 forms of thread- worm — Filaria piscium said Ascaris collaris*. Examples of the former 

 were coiled within the mesenteric folds, while the latter were chiefly enclosed in cysts, in 

 and upon the mucous membrane of the intestine. A fully-developed Ascaris collaris 

 (PI. XXXII. fig. 27) presented the foUovring characters — here given on account of certain 

 difficulties in the way of identification : — Body an inch in length, comparatively thick ; 

 head obtuse, trilobular valves of the mouth very small ; oesophagus narrow, communicating 

 with a broad intestine, bounded on either side by two slender csecal appendages of un- 

 equal length and vesicular at the free ends t ; caudal extremity rounded, rather narrower 

 than the head ; anal orifice in front, not far distant. In addition to these nematodes, 

 the intestine contained numerous specimens of Scolex polymorphus, and there was also a 

 minute trematode enclosed in a capsule beneath the peritoneal membrane. The anatomy 

 of various Scolex-forms has been beautifully illustrated by Prof. Van Beneden and 

 Wagoner % ; nevertheless I remark upon one or two particulars in passing. In this Scolex 

 (figs. 28, 29) the simple structm-e of the sclerous particles formerly aUuded to is most 

 satisfactorily seen, and it is difficult to understand why such discrepancy of opinion should 

 prevail in regard to their nature. Siebold long ago recognized their dermo-skeletal cha- 

 racter. The four presumed water- vascular canals take their origin by two single trunks, 

 one on each side of the lower part of the proboscidiform sucker ; there is no appearance 

 of intercommunication, however, between them and the cavity of the cup. The encysted 

 trematode corresponds in many respects with the Fasciola Flatessce of Mfiller, answering 

 more closely, however, to the Distoma atomon found by Uudolphi in Fleuronectes flesus 



* According to Miescher, Steenstrup, Wagener, &c., the Filaria are only young Nematoidea. 

 f In Cheiracanthus robustus, Diesing remarks the presence of four similar lemnisciform bodies. 

 X Die Entwickelung der Cestoden, &c. 1854. 



