MONOGRAPH OF THE EXISTING CKINOIDS. 



243 



the centrodorsal is relatively longer; again the radical resorption may be, as in 

 Zenometra (figs. 214-216, p. 241) and in Balanometra, entirety restricted to the 

 midradial areas, leaving the interradial areas standing up as high ridges and 

 making the centrodorsal appear far larger than it really is. 



FlO. 220. 



FIG. 218. 



FIG. 219. 



FIG. 221. 



FIG. 222. 



FIG. 225. 



FIG. 223. 



FlG. 224. 



FIG. 226. 



FIGS. 217-226. 217, DORSAL VIEW OF THE CENTRODORSAL OF A SPECIMEN OF ZENOMETRA COLVMNARIS FROM GEORGIA. 218. 

 LATERAL VIEW OF THE CENTRODORSAL OF A SPECIMEN OF ATELECRINUS BALANOIDES FROM PORTO Rico. 219, DORSAL VIEW 

 (IT THE CENTRODORSAL OF A SPECIMEN OF L.EPTOMETRA CELTICA (AFTER 1'. H. CARPENTER). 220, LATERAL VIEW OF THE 

 CENTRODORSAL OF A SPECIMEN OF THICHOMETRA VEXATOR FROM THE HAWAIIAN ISLANDS. 221, LATERAL VIEW OF THE 

 CENTRODORSAL OF A SPECIMEN OF TRICHOMETRA ASPERA FROM GEORGIA. 222, LATERAL VIEW OF THE CENTRODORSAL OF A 

 SPECIMEN OF TRICHOMETRA OBSCURA FROM SOUTHERN INDU. 223, LATERAL VIEW OF THE CENTRODORSAL OF A SPECIMEN 

 OF ATELECRLNUS CONIFER FROM THE HAWAIIAN ISLANDS. 224, LATERAL VIEW OF THE CENTRODORSAL OF A SPECIMEN OF 

 TRICHOMETRA EXPLICATA FROM THE PHILIPPINE ISLANDS. 225 DORSAL VIEW OF TUB CENTRODORSAL OF A SPECIMEN nr 

 FLOROMETRA ASPERRIMA FROM ALASKA. 226, LATERAL VIEW OF THE CENTRODORSAL OF A SPECIMEN OF FLOROMETK.I 

 ASPERRIMA FROM ALASKA. 



In the families Zygometrida; (figs. S3, p. 136, and 84, p. 137), Himerometridse 

 (figs. 85, p. 139, 86, p. 141, and 184-186, p. 235), Stephanometridse, Mariamet- 

 ridas (fig. 432, p. 349), Colobometridse (fig. 87, p. 143), TropiometridzB (figs. 88, 

 p. 145, and 303, p. 264), and Calometridse (fig. 89, p. 147) the centrodorsal is 



