62 ECHINODERMA OF THE INDIAN MuSEFM , PART VII. 



b* P.2 without a genital gland. 



c' centrodorsal large, conical or more or less columnar, the cirrus sockets in 

 definite columns, 

 d' two columns of cirrus sockets in each radial area : cirri with sliort seg- 

 ments distally, bearing dorsal spines ; size small. 



ADELOMETRA, p. 238. 



d* three or more columns of cirrus sockets in each radial area, 

 e' three or more columns of cirrus sockets in each radial area ; cirri 

 smooth, all the segments elongated ; calyx and arm bases smooth ; size 

 usually medium or large. 



PSATHYROilETRA, p. 234. 



e* three columns of cirrus sockets in each radial area: cirri long, witii 

 long segments proximally, short and sjiiny segments distally : calyx 

 and arm bases very spiny ; size medium or large. 



ZENOMETRA, p. 284. 



c** centrodorsal moderate or small, hemispherical or more or less discoidal, 

 the cirri irregularly arranged and closely crowded. 



d' cirri slender, much compressed, smooth, all the segments greatly elonga- 

 ted ; no opposing spine ; terminal claw nearly straight. 

 e> all the lower pinnules subequal, much elongated : P, composed of very 

 numerous short segments, P.; and following of elongated segments. 



THYSANOMETRA, p. 244. 



e* P, much shorter than P.^, but, like it, composed of elongated seg- 

 ments ; P.^ or Pj, or both, enlarged and stiffened. 



EUMETRA, p. 242. 



d'^ distal cirrus segments shorter than the proximal (the latter centrally 

 constricted), rarely longer than broad ; opposing spine always present, 

 e' 25 or more cirrus segments, 

 f P, very much longer than P.;,, excessively elongated, with more than 

 20 segments which are greatly elongated distally. 



TRICHOMETRA, p. 239. 



f^ P, less than one third longer than P,, the distal segments not 

 especially elongated. 

 g' P| only slightly longer than P.^, with ten segments ; size small. 



NANOMETRA, p. 241. 



a^ P[ about one third longer than P._,, with 30—45 segments which 

 are short proximally, and never more tiian twice as long as broaa 

 distally ; size medium or large. 



CYCLOMETRA, p. 238. 



