450 



EMBRYOLOGY 



left portions of the body cavity, there is developed still a third part, was 

 already mentioned in considering the hydrocoele (comp. p. 413). 



Figs. 221 (and 222).— Pentacrinoid larva (C) and swarming larvae {A and B) of 

 Anlednn (after Thomson, from Bilfoub's Com'parative Embryology). The moat 

 anterior ciliated ring, described by Bubv, is lacking on the swarming larvw, 

 which are placed in the positions in which thev aubaeauently become attached 

 (comp. Fig. 217, p. 441). 



