CLARK] NEW GENERA OF RECENT FREE CRINOIDS 349 



The following are the described species of the genus : 



Nanometra denticnlata (P. H. Car- Nanometra pusilla (P. H. Carpenter) 

 penter) " wilsoni (Bell) 



" minckerti A. H. Clark 1 



3. TROPIOMETRA, gen. nov. 



Centro-dorsal discoidal, bearing 20 to 30 marginal cirri in one 

 more or less irregular row ; cirri stout, short, with 20 to 35 segments, 

 all wider than long, perfectly smooth, the opposing spine on the 

 penultimate absent or but faintly indicated; terminal claw small and 

 short ; disk and ambulacra naked ; costals broad and nearly flat, 

 united by bifascial articulation, in close apposition laterally, and 

 more or less "wall-sided ;" always ten arms ; first brachial oblong, 

 and rather disproportionately large ; second brachial wedge-shaped, 

 rather larger than the first ; first two brachials in close lateral contact 

 with those on adjacent rays, and more or less flattened laterally; 

 following brachials very short, oblong, discoidal, or very slightly 

 quadrate, the arms with or without a median keel ; third and fourth 

 brachials united by syzygy ; other syzygies usually between the ninth 

 and tenth and fourteenth and fifteenth, or approximately in those 

 positions ; distally syzygia occur with intervals of from 2 to 9 bifas- 

 cial articulations ; lower pinnules subequal, stout, prismatic, sharply 

 carinate, with 20 to 25 short segments, mostly broader than long, 

 flattened externally ; distal pinnules very slender, elongate, usually 

 non-carinate. 



Color (in spirits) purple or purple-brown, often more or less 

 spotted or blotched with yellow ; sometimes yellow, or reddish purple 

 and yellow ; rarely white. 



Type of the genus. — Comatula earinata Lamarck, 1816. 



This genus is equivalent to a part of Dr. Carpenter's "Milberti 

 group," and contains four species, their united ranges including, so 

 far as can be judged, all tropical seas, the Red Sea, northward to 

 Japan, and southward to Chile and the Cape of Good Hope. 



The known species referable to this genus are : 



Tropiomctraafra (Hartlaub) Tropiomctra brazilicnsis (Rathbun) 



earinata (Lamarck)' macrodiscus (Hara) 



1 Xanomctra minckerti, new name for Antedon minor A. H. Clark, preoccu- 

 pied. I take great pleasure in dedicating this interesting species to Mr. YVil- 

 helm Minckert, in recognition of his excellent work on the unstalked crinoids. 



'Antedon capensis Bell, described in the "Basicurva group, - ' is a synonym 

 of this species. I have compared specimens identified by Professor Bell with 

 others from Zanzibar and find them identical. 



