portion of the bud, v/hile by this process of elongation an- 

 teriorly the connection with the stolon comes to be left be- 

 hind in the posterior region. The side next th^'e stolonic 

 wall becomes the ventral surface of the bud, and that oppo- 

 site it the dorsal. 



The protuberances of the stolonic ectodenn, which 

 Seeliger (29) describes as occurring at the base of the bud- 

 rudiment in C_lavelina, are not present in Perophora ; they 

 are merely simple ectodennal sacs, filled with blood-cells, 

 and do not contain an evaginatlon of the partition-wall. 

 Seeliger calls them "TIahrkanrnern", and regards them as res- 

 ervoirs of food-material for the developing buds. 



Before going on to describe the origin of the va- 

 rious internal organs, some of which have by this time begun 

 to make their appearance, I wish to say a word about the par- 

 tition-wall of the stolon. 



A.S the inner vesicle of the bud is formed entirely 

 from this structure, it is a matter of importance to know 

 from what it is derived in the larva. 



It has never been observed in Perophora how the 

 stolonic partition arises, although it is usually supposed 

 to be of endodermal origin from its likeness to the similar 

 structure in Clavelina. 



Van Beneden and Julin (33) have shown that in the 

 larva of Clavelina it is formed as a direct continuation of 

 the epicardiim, which arises as a diverticulum from the pos- 

 terior wall of the branchial sac, and is therefore entirely 



■12. 



