PHYLUM TROCHELMINTHES 



311 



The various species of Dinophilus are marine, with the exception of one which 

 is an inhabitant of brackish water. In certain of its characters the tendency 

 to a segmentation of the body, and the disposition of nephridia in pairs corre- 

 sponding to the imperfectly separated segments Dinophilus approximates 

 towards a phylum that has yet to be dealt with the Annulata and is some- 

 les looked upon as a member of the class Archi- Annelida of that phylum. 



Irn- 



FIG. 253. Chaetonotus maximus. 



Highly magnified. (After Zelinka,) 



FIG. 254. Chaetonotus maximus, or- 

 ganisation, brn. brain ; <jld. adhesive 

 gland ; men. mesenteroii ; mo. mouth ; 

 as. oesophagus; 01: ovum; ocar. ovary; 

 retr. retractor muscles ; -cent. mus. ventral 

 muscle. (After Zelinka.) 



Class III. GASTROTRICHA. 



The Gastrotricha (Figs. 253 and 254) are a small group of minute fresh-water 

 animals, which are apparently allied, though certainly not very closely, to the 

 Rotifera, and are on that account placed in the present phylum. The body is 



