490 ANATOMICAL AND PATHOLOGICAL OBSERVATIONS, 



the Ctenurus, with the exception of the cells, which are not 

 arranged so regularly. The sac is also composed of two mem- 

 branes, each having structures exactly similar to that of the 

 Ccenurus. 



I have divided the animals composing this genus of 

 Entozoa into two classes, in consequence of the difference of 

 structures met with in the cyst. Those species, in which the 

 cyst is only composed of one membrane, derived from the 

 compressed tissues of the infested being, have been placed 

 near to the Acephalocysts ; and those in which the cyst con- 

 sists of two membranes already described, compose the other 

 division. 



The Cysticerciis cellulosus is an example of the first of these 

 divisions. In this animal the cyst is very vascular, i.e. more 

 so than the surrounding textures, so that in this respect it is 

 quite similar to the analogous structure in Acephalocystis. 

 As an example of the animals belonging to this division of the 

 genus, there is another species which appears to be nonde- 

 script. This Cysticercus w^as found in the Museum of the 

 Eoyal College of Surgeons, but unfortunately the jar was not 

 labelled, so that I am uncertain from what animal it was got. 

 It is enclosed in a cyst formed by the omentum alone ; these 

 cysts are pedunculated,, and although quite continuous with 

 the healthy portion of the membrane, it is so puckered and 

 constricted at the pedunculated portion as to be quite im- 

 permeable, so that the enclosed animal can obtain no nourish- 

 ment from without, except through the portion of omentum 

 forming the cyst. The cyst is very vascular, and generally 

 contains a quantity of thin granular looking matter (probably 

 the matter intended for the food of the enclosed animal). The 

 double circlet of teeth in this species is remarkable for their 

 great length. In many specimens which came under my 

 notice numerous small globular bodies were observed, sur- 

 rounded externally with hooked spines, and attached to the 



