MONOGRAPH OI* THE EXISTING CRINOIDS. 



373 



The ventral or inner faces slope inward, forming collectively a funnel-shaped 

 space occupying the center of the radial pentagon (fig. 442, p. 351). These faces 

 are usually more or less divided up by delicate calcareous processes which extend 



FlQ. 509. 



FIG. 510. 



Fio.511. 



FIG. 512. 



FIGS. 509-513. 509, DORSAL VIEW OF THE RADIAL PENTAGON or A SPECIMEN or IlATHROMETr.A DENTATA FROM SOUTHERN 

 MASSACHUSETTS. 510, DORSAL VIEW OF THE RADIAL PENTAGON OF A SPECIMEN OF THAUMATOMETRA TEMIS FKOM TIIK 

 SEA OF JAPAN; THE ROSETTE HAS BEEN BROKEN AWAY. 511, DORSAL VIEW .it- THE RAI.IAI. PENTAGON- or A SPECIMEN OF 

 HELIOMETRA GLACIALIS AFTER THE REMOVAL OF THE ROSETTE (AFTER P. II. CARPENTER). 512, DORSAL MEW OF 



THE RADIAL PENTAGON OF A SPECIMEN OF I'ENTAMETROCRINL'S SEMPEP.I (AFTER I'. II. ('.Mtl'llNTER). 513, DORSAL VIEW OF 

 THE RADIAL PENTAGON OF A SPECIMEN OF I'ENTAMETROCRINUS JAPOXKTS FIWiM SOUTHERN JAPAN. 



to meet the ventral face of the rosette, and collectively form a complicated net- 

 work, filling up the central funnel and often partially bridging over the ventral 

 radial furrow so as to convert it into an incomplete canal. In many forms these 



