EMBRYOLOGY OF ECHINODERMS. 



133 



they are much alike. The mouth of the pluteus is at the 

 anterior end of the body, while the anterior end of the 

 body of the starfish larva is elongated into a long lobe 

 (Fig. 78, a), and the mouth (m) is about midway between 



n 



FIG 79. 



PIG. 79. Dorsal view of the same larva. (Drawn from nature by 

 E. B. Wilson.) 



Letters as in Fig. 78. 



the anterior end (a), and the posterior (b) on the ventral 

 surface. It lies, as it does in the sea-urchin pluteus, in a 

 furrow, with a ciliated ridge (1) in front of it, and an- 

 other (2) between it and the anus (o). The long O3sopha- 



