COMPARISON OF THE LARVA DF ANTEDON ROSACEA WITH 

 THAT OF OPHIURA BREVISPINA. 



While I was studying the 1 irvae of Ophiura brev- 

 ispina, characters were constantly being found which 

 reminded me of the larvae of Antedon as described 

 by BURY (1). Some of these points of resemblance 

 ore no ioubt only su] ?rfieial but others are cue;. 

 as to make it worth while to devote a short chapter 

 to the pointing out of ths similarities of the two 

 larvae. 



The entire ciliation of the very young larvae 

 gives place in both, to a series of transverse cil- 

 iated bends, five in Antedon ,four in Ophiura. Ths 

 band nearest the anterior end cf the Antedon larva, 

 however, is small and incomplete. Two bands only 

 in each case surround that part of the larvae from 

 which the iff; is form L. 



Th: blastopore, in both larvae, after shifting 

 fro. 1 ?. -for position to one on the ventral sur- 

 face, closes and the archenteron loses its connect- 

 ion v:ith the ectoderm oni lies free in the body cavit 



In the seven day embryo of Antedon and stage 



