MONOGRAPH OF THE EXISTING CRINOIDS. 233 



The inner surface is studded with small openings which are the inner ends of 

 canals leading from the inner cavity to the centers of the cirrus sockets exteriorly, 



FIG. 182. 

 FIGS. 181-182. 181, DORSAL VIEW or THE YOUNGEST SPECIMEN OFCOMATULA ROTALAKIA OBTAINED JIY THE " CHALLENGER," 



SHOWING THE FUNCTIONAL CIRRI (AFTER P. H. CARPENTER). 182, DORSAL VIEW OF A SPECIMEN OF COMANTHUS PAKVICmiiA. 

 SHOWING CIRRI PRESENT IN ONLY TWO OF THE DJTERRADLVL ANGLES OF THE CENTRODORSAL (AFTER 1'. H. CARPENTER). 



and are continued into the cirri (figs. 66-68, p. 93). In Antedon bifida these canals 

 average, according to W. B. Carpenter, -gfa inch in diameter, but they are pro- 

 portionally larger in species having larger cirri. Most commonly the walls of this 



79140 Bull. 8215 16 



