206 



ANIMAL PARASITES AND MESSMATES. 



We have found in bats two taeniae, both incompletely 

 developed, and occupying the digestive tube. One has 

 a rostellum without hooks, like the taeniae of the vegetable- 

 feeders, the other has hooks like those of the carnivdra. 

 These cestode parasites are observed to be of two prin- 

 cipal forms ; the first vesicular, like the finger of a glove 

 partly drawn inwards. They are always lodged in the 

 midst of the flesh, or in a closed organ in the middle of 

 a cyst ; under this form the cestode worm is harboured 

 by a host which is to serve as a vehicle to introduce him 

 into his final host. He is a parasite on a journey ; he is 

 always agamous, and usually bears the name of cysti- 

 cercus (Fig. 49). As to the second form, it is like a 



■ ■ ribbon; it attains a great 



length, always occupies the 

 intestine, attains its com- 

 plete and sexual develop- 

 ment, and lays an innumer- 

 able quantity of eggs which 

 are disseminated with the 

 evacuations. 



The rabbit harbours a 

 cysticercua which has its 

 final destination in the dog 

 (a xenosite); but indepen- 

 dently of this stranger, it 



Fig.49.-Cysticercus; a, upper part, of giveS hospitality to a SpCcial 



is about to separate; c, neck of the taenia in itS intCStineS. iniS 

 worm; d, the head, showing the • •- w^^vm +1ta T^iiin 



suckers and the crown of hooks. IS ItS OWU WOrm, Xlie 1 WUia 



pectinata, which is a nos- 

 tosite. All the herbivora are in a similar case ; the ox 

 and the sheep possess a peculiar taenia of their own, 



