i66 



COLLEGE ZOOLOC.Y 



off from the "neck." Archigetes (Fig. no) differs from other 

 tapeworms both in structure and habit; it has only one proglot- 

 tis, and lives in the ccelom of an annelid, Tubifex. 



A few Cestodes and their hosts are given in Table VIII (from 

 the Cambridge Natural History). 



TABLE VIII 



THE LIFE-HISTORIES OF A FEW CESTODES 



NAME 



FINAL HOST 



INTERMEDIATE HOST 



1. Taenia saginata 



2. T. serrata 



3. Dipylidium cani- 



num 



4. Hymenolepis di- 



minuta 



5. Drepanidotaenia 



setigera 



6. Bothriocephalus 



latus 



Man 

 Dog 



Man, dog, cat 

 Man, mouse, rat 



Goose 

 Man, dog 



Ox, giraffe (in muscles). 

 Rabbit, hare, mice (liver and 



peritoneum). 

 Flea of dog (body-cavity). 



Meal-moth, Asopia farinalis; 



also certain Orthoptera and 



Coleoptera. 

 Water-flea, Cyclops brevicau- 



datus. 

 Pike, perch, trout, etc. 



5. FLATWORMS IN GENERAL 



Definition. - - Phylum PLATYHELMINTHES. - - FLATWORMS. - 

 Triploblastic animals; bilaterally symmetrical; single gastro- 

 vascular cavity; no anus; presence of coelom doubtful. 



The flatworms are more highly organized than the CCELEN- 

 TERATA or CTENOPHORA and are distinctly triploblastic. The 

 middle germ-layer, the mesoderm, which is well developed in flat- 

 worms, is connected with several important systems of organs, 

 since it is from this layer that the muscles, the excretory system, 

 and the reproductive ducts originate. The development of these 



