PART a A MONOGRAPH OF THE EXISTING CRLNOIDS 77 



Genus EUMETRA A. H. Clark 



Eumetra A. H. CLARK, Smithsonian Misc. Coll., vol. 52, pt. 2, 1908, p. 230 (type species E. chamber- 

 laini); Proc. Biol. Soc. Washington, vol. 22, 1909, p. 177 (referred to the Thysanometrinae) ; 

 Crinoids of the Indian Ocean, 1912, p. 10 (absent from Japan; reason), p. 26 (range), p. 62 (in 

 key), p. 242 (original reference; type); Journ. Washington Acad. Sci., vol. 7, 1917, No. 5, p. 127 

 (referred to the Antedoninae) ; No. 16, p. 506 (in key; range); Unstalked crinoids of the Siboga- 

 Exped., 1918, p. 198 (in key; range), p. 213 (key to the included species). GISLN, Zool. Bidrag 

 Uppsala, vol. 9, 1924, p. 231. 



Iridometra (Eumetra) A. H. CLARK, Notes Leyden Mus., vol. 34, 1912, p. 137. 



Diagnosis. A genus of Antedoninae in which P 3 is much the longest and stoutest 

 pinnule on the arm; there are rarely less than XL cirri of which the component segments, 

 16 to 33 in number, have produced distal ends overlapping the proximal ends of those 

 succeeding; the outer cirrus segments are much longer than their proximal breadth; 

 and the brachials have smooth or only very finely spinous distal ends. The arms are 

 at least 75 mm. in length. 



Type species. Eumetra chamberlaini A. H. Clark, 1908. 



Geographical range. From the Lesser Sunda Islands to the Philippines and 

 southern Japan. 



Bathymetrical range. From 69 to 146 meters. 



Remarks [by A.M.C.]. I am doubtful about the inclusion of the species aphrodite 

 in this genus. The differences between the description of it and those of the species 

 of Dorometra with P 2 intennediate hi size between PI and P 3 , such as aegyptica, appear 

 to be trivial and mainly due to the large size of the types of aphrodite. The very long 

 cirri of Eumetra chamberlaini with almost twice as many segments as aphrodite and 

 no opposing spine, mark it off very clearly from the latter species and indeed from 

 the rest of the Antedoninae. There is a parallel with regard to cirrus elongation in the 

 genus Antedon, which includes species with the longest cirrus segments less than twice 

 as long as wide as well as others like A. longicirra where they may be six tunes as long as 

 wide. But in Antedon the number of segments is not considerably augmented at the 

 same tune as the segments are elongated, unlike Eumetra chamberlaini. 



KEY TO THE SPECIES OF EUMETRA 



a 1 . Cirri very long and slender, their length equal to from one third to one half the length of the 

 arms, composed of 25-33 (usually 25-26) much elongated segments of which the longest are 

 about five times as long as the proximal breadth and the last three or four are about two and 

 a half or three times as long as broad; no opposing spine; terminal claw very slightly curved 

 (Philippine Islands; 142-146 meters) ...chamberlaini (p. 77) 



a a . Cirri shorter and less slender, their length equal to about one quarter of the arm length, composed 

 of 16-18 segments which are not especially long, the longest (fifth-seventh) being nearly or 

 quite three times as long as broad proximally, and the last three or four less than twice as long 

 as the distal breadth; a prominent opposing spine; terminal claw strongly curved (Lesser Sunda 

 Islands; 69-73 meters).. aphrodite (p. 80) 



I.I Mi: I in CHAMBERLAINI A. H. Clark 



Eumetra chamberlaini A. H. CLARK, Smithsonian Misc. Coll., vol. 52, pt. 2, 1908, p. 231 (description; 



Albatross Sta. 5178); Proc. U.S. Nat. Mus., vol. 39, 1911, p. 563 (Albatross Sta. 5277); Crinoids 



of the Indian Ocean, 1912, p. 242 (Philippine Is.; 78-80 fms.)< Unstalked Crinoids of the Siboga- 



Exped., 1918, p. 213 (in key; range; references). 

 Iridometra (Eumetra) chamberlaini A. H. CLARK, Notes Leyden Mus., vol. 34, 1912, p. 137 (compared 



with E. aphrodite). 



