ANNELIDA 



313 



III. DINOPHILUS. 



Although the development of Dinophilus is not yet known 

 in detail, we include this aberrant form in the course of our 

 present account, because the adult animal itself remains to 

 a certain extent at the stage of an Annelid larva. 



In its outward shape (Fig. 149) Dinophilus presents a 

 striking resemblance to certain 

 polytrochal Annelid larv^, e.g., 

 to those of Ophryotrocha and 

 a larval SylHs not yet de- 

 scribed, which we observed in 

 the "tow" at Trieste. This 

 applies not only to the ciliated 

 bands, the distribution of the 

 sensory hairs, and the ventral 

 tail-like appendage, but more 

 especially to the entire habit 

 of the worm. The caudal 

 appendage of Dinophilus, like 

 that of the Annelid larva in 

 question {Ophryotrocha sp.), is 

 segmented. For this reason, 

 as also on account of its ven- 

 tral position, it recalls the foot 

 of the Rotatoria, a comparison 

 which indeed does not appear 

 altosfether without foundation 

 when one considers the simi- 

 larity in the organization of 

 Trochophore larva to that of 

 the Rotatoria, which has al- 

 ready been emphasized (p. 259). 

 Should the statement prove to 

 be correct that the five pairs 

 of nephridia possessed by Dino- 

 philus (Fig. 149) end blindly 

 in the body cavity (E. Meyer), there would exist in this 

 particular also conditions such as are found in the Annelid 



Fig. 149.— Female of Dinophilus 

 gyrociliatus (after E. Metek, from 

 LiNG's Lehrbuch). a, eye ; aw, anus; 

 ed, hind-gut ; i/i, mouth ; md, mid-gut ; 

 n, nephridia; o, ovary; ph, pharynx; 

 phd, pharyngeal glands ; ufc, ciliated 

 band. 



