264 



BULLETIN 82, UNITED STATES NATIONAL MUSEUM. 



A rocky bottom, or a bottom covered with highly calcareous organisms such 

 as calcareous algse, corals or lithothamnion, tends to induce the development of 

 very long and very stout cirri which, tliough flexible distally, are comparatively 



Fig. 299. 



Fig. 301. 



Fig. 300. 



Fig. 302. 



FiG. 303. 



Fig. 304. 



Fig. 303. 



FiO.S. 298-305.— 298, Ventral view of the centrodorsal of a specimen of Tiiaumatometra tenuis from tee Sea of Jaf.in. 



299, Ventral VIEW OF tue centrodorsal of a specimen of Pentametrocrinvs japonicus from southern Jap.ix. 



300, Ventral view of tue centrodorsal of a spectmen of Atelecrinus bal-vnoides (.vfter P. II. Carpenter). 301, 

 Lateral view of the centrodorsal of a specimen fiF Nemaster lineata from Brazil, witu the rosette and two 



RADULS IN POSITION (AFTER P. II. CARPENTER). 303, VENTRAL VIEW OF THE CENTRODORSAL OF A SPECIMEN OF TlIAUlIA- 

 TOCRINC3 RENOVATUS (AFTER P. H. CARPENTER). 303, LATERAL VIEW OF THE CENTRODORSAL, AND THE RADIAL PENT.l- 

 CON WITH TWO RADULS REMOVED, OF A SPECIMEN OF TBOPIOMETRA PICTA (AFTER P. H. CARPENTER). 304. \"ENTRAL VIEW 

 OF TUE RADIAL PENTAGON OF A SPECIMEN OF TROPIOMETRA PICTA; ONE OF THE R-VSAL RAYS (THE ANTERIOR IN THE FIGURE) 

 UAS BEEN REMOVED (AFTER P. IL CARPENTER). 305, THREE UNITED RADIALS FROM A SPECIMEN OF CoMATUI.A ROTALARIA, 

 VIEWED FROM TBE INTERIOR OF THE CALYX (AFTER P. H. CARPENTER). 



rigid proximally (fig. 309, p. 267) ; such cirri, most perfected in the species of Thalas- 

 sometridfc, are more or less characteristic of some or all of the species of NemasUr, 

 Cai/illaster, Coinanthus, Ilimerometra, Heterometra, Oxijmetra, Pontiometra, Dichro- 



