MONOGRAPH OF THE EXISTING CRINOIDS. 289 



strong; lateral comprcssiou of tlio cirri; iu other words, tlic reduction of tlio calca- 

 reous base iisuallj' takes place faster along the transverse than along the dorso- 

 ventral axis. This condition is not found outside of the Macroplireata, where it is 

 especially characteristic of the Atelocrinida; (figs. 405, 406, p. 311, and 414, p. 319), 

 the Pentametrocrinidse (fig. 404, p. 311), and the genera Psathyrometra (fig. 379, 

 p. 301), Thjsanometra (fig. 372, p. 299), and Coccometra (figs. 374-376, p. 299) of the 

 Antedonidjp. 



An increase in the stoutness of the cirri unaccompanied bj- any increase in the 

 length or in the number of segments — indeed sometimes correlated with a reduc- 



< JITlTl:|:|;(l!(lttolat8tBtoH08(llllHllll H H H I 1 H I I II il ) 1 1 

 Fig. 345. 



<^-LLUlJ!Jj u-- m- ^ m m 1 I I 1 y TTD 



Fig. 346. 



I- 1- h h hi- F t^ K M tLi-LX-k-L-fe--L--L— L-JLJJ 



Fig. 347. Fio. 348. 



Figs. 345-348.-345, A CIRRC3 FROM A SPECIMEN OF CENOMETRA UNICORNIS FROM THE PhJUTPINE ISLANDS VIEWED (o) DOB- 

 SAU.T AND (6) LATERALLY. 346, A CIRRUS FROM A SPECIMEN OF CYLLOMETRA ALBOPIIRPITJEA FROM SOL^I^F.RN JAPAN STEWED 

 (a) DOESALLT AND (b) LATERALLY. 347, LATERAL \1EW OF THE CIRRUS OF A SPECIMEN OF CYIJ.OUETRA UAMCA FROM 



THE Ki Islands. 348, A ciRRDS from a specimen of Ctllometra manca from the Ki Islands viewed (a) dorsallt 



AND (6) LATERALLY. 



tion in regard to the latter — may be considered as among the chief characteristics 

 of the cirri of the Oligophreata, though it is much more marked in certain groups 

 or species than in others. In its simplest form it is best seen m the Charitometri(la) 

 (figs. 99, p. 160, 100, p. 162, and 369, 370, p. 299) and Comactiniina; (figs. 76, p. 129, 

 and 327, 328, p. 281), and particularly in the Tropiometridse (figs. 88, p. 145, and 356, 

 p. 293), where it is not obscured by an mcrease in the length of the cirri. In 

 these forms the cirri, like th(3se of most of the Macroplireata, are of the same 

 nature throughout and show no division into specialized areas. 



