VII 



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- 

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



FIG. 253. Chaetonotus maximus. 



Highly magnified. (After Zelinka.) 



FIG. 254. Chaetonotus maximus, or- 

 ganisation, bi'ii. brain ; </M. adhesive 

 gland ; -IMS. mesenteron ; mo. mouth ; 

 as. oesophagus ; oc. ovum ; orar. ovary ; 

 i-iti: retractor muscles ; ci.nt. /nits, 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 



