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 already extended numerically far beyond the proper limits, 
there is in the present instance no alternative. Ascaris acanthocaudata (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. 
Hippoglossus vulgaris.—A. specimen dissected on the 4th of May, 1854, yielded two 
forms of thread-worm—Filaria piscium and 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 . 
(Pl. XXXII. fig. 27) presented the following 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; cesophagus narrow, communicating 
with a broad intestine, bounded on either side by two slender cæcal appendages of un- 
equal length and vesicular at the free endst; 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 
Wagener? ; nevertheless I remark upon one or two particulars in passing. In this Scolex 
(figs. 28, 29) the simple structure of the sclerous particles formerly alluded 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 ency: 
trematode corresponds in many respects with the Fasciola Platesse of Miller, answering 
more closely, however, to the Distoma atomon found by Rudolphi in Pleuronectes flesus — 
* According to Miescher, Steenstrup, Wagener, &c., the Filariæ are only young Nematoidea. 
T In Cheiracanthus robustus, Diesing remarks the presence of four similar lemnisciform bodies. 
1 Die Entwickelung der Cestoden, &c. 1854. 
