INVERTEBRATES 



Cestoda. 



The tape-worms are internal parasites of verte- 

 brates. Their larvae (cjsticerci or bladder-worms) 

 are parasites of other vertebrates or of invertebrates. 

 Dr. E. M. Walker has given me the following list 

 of species that are found here. It is merely a begin- 

 ning. 



Dipylidium caninum (L.) in the Dog, and Cat 



(adult). 



Taenia serrata Goeze in the Rabbit (cysticercus). 

 " saginata Goeze in Man (adult). 

 " echinococcus v. Sieb. in Man (cysticercus). 

 " serialis (Gerv.) in the Rabbit (cysticer- 

 cus). 



COELENTERATA. 



Our only representative of this group that con- 

 tains so very many marine species is the well-known 

 Hydra, that has been the subject of such a large 

 number of experiments in regeneration. 



Hydra viridissima Pallas (Dr. E. M. Walker). 

 " polypus L. Sunnyside. 

 " oligactis Pallas Michigan.* 

 " vulgaris Pallas Michigan.* 



POBIFERA. 



Our fresh-water sponges are few in kinds, but 

 often grow in great luxuriance. 

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