Oumings — Development of some Paleozoic Bryozoa. 53 



This metamorphosis, or kathembryonic* stage, is not present 

 in those organisms which pass directly from the larval to the 



m 





Figures 20-25. — Further stages in the formation of the free-swimming 

 larva of Phalangella ( = Tubulipora). (After Barrois.) 



24 and 25. Optical sections of 21 and 22 respectively ; 23. Beginning of 

 formation of the mantle ; 22 and 25. Completed larva. 



or, oral region ; C, invagination cavity of adhesive organ ; S, adhesive 

 organ (sucker); cm, mantle cavity; m, mantle. 



Fig. 25 is modified from Barrois' original figure, in accordance with his 

 later views. 



All figures x 160. 



* Kara, in the sense of opposition or contrast. 



