A. H. CLARK: THE CRINOIDS OF THE INDIAN OCEAN. 179 



CALOMETRA CALLISTA. 



Antedon callista 1907. A. H. Clark, Proc. U. S. Nat. Mus., vol. 33, p. i:i5. 

 Calomefm callista 1907 . A. H. Clark, Smiths. Miscell. Coll. (Quarterly Issue), 



vol. 50, part 3, p. 363. 



Habitat. — Southern Japan. 



Depth.— 107-139 fathoms. 



CALOMETRA DISCOIDEA. 

 Antedon discoidea 1888. P. H. Carpenter, "Challenger" Reports, vol. 26, 



Zoology, p. 134, pi. X, figs. 1, 2. 

 Galometra discoidea 1907. A. H. Clark, Smiths. Miscell. Coll. (Quarterly Issue), 



vol. 50, part 3, p. 383. 



Habitat. — Ki and Philippine Islands. 

 Depth. — 140-240 fathoms. 



Genus OREOMETRA, nov. 



Genotype. — Oreometra marice, sp. nov. 



Diagnosis. — A genus of Calometridas in which the IIBr series are 4 (3+4) ; 

 the centrodorsal is thick-discoidal, with a single marginal row of cirri, whose 

 sockets are largely supported by the radials ; cirri long (nearly half of the 

 arm length), rounded rhombic in cross-section, the outer segments bearing triple 

 dorsal spines ; first segment of the earlier pinnules not greatly enlarged. 



OREOMETRA MARINE, sp. nov. 



Antedon macronema Brit. Mus., MS. 



Description. — ^Centrodorsal thick discoidal, bearing a single fairly regular 

 marginal row of cirrus sockets ; the flat dorsal pole is 4 mm. in diameter. 



Cirri XV, 44-47 (usually 46-47), 25 mm. to 27 mm. long; all the segments 

 are approximately equal, all being about twice as broad as long. The ventral 

 and the lateral distal edges of the segments project rather strongly over the 

 base of the succeeding segments. The cirri are rounded rhombic in cross sec- 

 tion, suggesting the cirri of Neometra acanthaster though the corners are less 

 sharp. On about the fourth segment a faint very narrow longitudinal ridge is 

 visible ; after the middle of tlie cirrus this becomes a narrow low sharp carina- 

 tion, and terminally grows into a fairly prominent rounded spine. Tiie cirri 

 taper slightly in the outer half. In the distal third of the cirri supplementary 

 spines appear, one on either side of the central carination, at first small and 

 confined to the vicinity of the distal edge, but on the terminal segments nearly 

 as large as the median spine ; the spine on the antepenultimate segment is 

 single; the opposing spine is laterally broadened. The cirri as a whole are 

 moderately stout. 



