542 THE ANATOMY OF INVERTEBRATED ANIMALS. 



Thus far, although the organization of Sagitta is very- 

 peculiar, it presents analogies both with the Nematoidea and 

 with the Anyielida. But its development, as described by 



Fig. l^i.—Sagitta Mpunctata.—a, the head, with it8 eyes and appendages ; 5, the 

 anus ; c, the ovary ; c?, the testicular chambers. 



Kowalewsky,* is, in some respects, unlike anything at pres- 

 ent known in either of these groups. Yelk-division takes 

 place as usual, and converts the eggs into a vesicular morula, 



ISTl. 



" Memoires de I'Academie Imperiale des Sciences de St.-Petersbourg, 



