MONOGRAPH OF THE EXISTING CRINOIDS. 



251 



elongated, in marked contrast to the conditions found in the other cirri, but quite 

 similar to the conditions found in the large cirri of species of more primitive genera, 

 and thus indicating the relationships of superficially very different forms. 



W. B. Carpenter, speaking of the development of the centrodorsal in Antedon 

 bifida, says: "At the beginning of the unattached stage the centrodorsal has the 



Fig. 243. 



Fig. 244. 



Fig. 245. 



Fig. 247. 



Fig. 246. 



FlO. 248. 



Fig. 249. 



Figs. 243-249.-243, Ventkal view of the centkodobsal or a specimen or Comanthus parvicirra from the Philippdje 

 Islands (after P. n. Carpenter). 244, \'e.n'Teal vxew of the centrodorsal of a specimen of Comantuus PAR^nciRK.< 

 from the pnilipptxe islands (after p. h. carpenter). 245, ventral \1ew of the centrodorsal of a speauen of 

 comanthus par\^cikra from the philtppine islands (after p. h. carpenter). 246, ventral view of the centro- 

 dorsal of a specimen of comaster fruticosus from the philippine islands. 247, v^entral view of the centrodorsal 

 of a speomen of comanthus par\acmra from the philippine islands (after p. h. carpenter). 248, ventral %tew 

 of the centrodorsal of -v specimen of comanthus parmcirra from the philippine isl.vnds (after p. u. carpenter). 

 249, Ventral view of the centrodorsal of a specimen of Comanthus parvicirra from the Philippine Islands (after 

 P. H. Carpenter). 



form of a basin with its lip turned inward; its diameter is about 0.03 inch, and its 

 height about 0.012 inch. Its basal surface is somewhat depressed in the center, 

 and here there is for a time distinguishable a minute 5-rayed perforation which 

 previously formed the communication between the cavity of the basin and the 



