92 OF THE AMATOMY AND DEVELOPEMENT 



continuous with the healthy portion of the membrane, it is so 

 puckered and constricted at the pedunculated portion, as to be 

 quite impermeable, so that the enclosed animal can obtain no 

 nourishment from without, except through the portion of omentum 

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

 tains 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 nu- 

 merous u small globular bodies were observed, surrounded externally 

 with hooked spines, and attached to the internal surface of the 

 cyst, apparently by means of the spines. These bodies, although 

 the intermediate stages between them and the young gemmules 

 could not be seen, I considered the young Cysticerci in an ad- 

 vanced stage of growth, and I was led to do so, because they 

 were often observed on the free surface of the omentum, attract- 

 ing and puckering it together in folds, evidently the commence- 

 ment of the process for the formation of a cyst, and in many 

 instances they had completely enveloped themselves. It has not 

 yet been decidedly made out, in what manner the gemmules 

 escape from the body of the Cysticercus, but from the observa- 

 tions I have made, it appears that they must first escape from the 

 pedicle where they are formed into the sac, and then from the 

 sac to the cyst. I am led to this supposition in consequence of 

 having observed on several occasions the sac of the animal rup- 

 tured, and great numbers of the globular spined bodies attached 

 to the inner surface of the cyst. How they escape from the cyst 

 I have not been able to determine. 



Those Cysticerci having the cyst composed of a double mem- 

 brane, do not differ in any other particular from those of the pre- 

 ceding division of the genus. The best example of this peculiarity 

 of structure, exists in a species found in the liver of the rat, and 

 which I have denominated Cysticercus Eattus. The specific 

 characters are given in the synopsis at the end of the Paper. 



In all the details, then, we find a great similarity between 

 Csenurus and Cysticercus, with this exception, that the latter is 

 simple, whereas the former, like all the other Accphalocysts, is a 



