A MONOGRAPH OF THE EXISTING CRINOIDS 9 



ifc'. Pi, P2, and Pj of the same length, composed of segments which have 

 prominent spinous distal ends, at least in the outer portion; cirri with 

 14-21 segments most of which are about as long as broad; 10 arms 

 30-60 mm. long (southern Japan to the Philippine Islands; 100-106 



meters) Alisometra (p. 112) 



k'. P2 slightly longer and stouter, or at least stouter, than Pi or Pj, though 

 all three pinnules are similar, and are entirely smooth; cirri with 15-29 

 short segments, becoming about as long as broad distally; 10-21 arms 

 30-100 mm. long (from southern Japan and the Philippine Islands to 

 Torres Strait and westward to Solor Strait and the coast of Annam; 



0-146 meters) Iconometra (p. 88) 



P. Pi shorter, more slender, and more delicate than P2, and composed of shorter 



segments. 



j'. Usually more than 10 arms, the IIBr and IIIBr series 2; cirri moderately 



long and slender with the earlier segments usually longer than the distal, 



which are broader than long (from southern Japan and the Bonin Islands 



southward to the Philippine, Kei, and Lesser Sunda Islands, and westward 



to the Persian Gulf; 22 [?15]-329 [?731] meters) CyUometra (p. 134) 



j'. Never more than 10 arms; cirri short and rather stout with the segments 



subequal, about as long as broad or broader than long, or slightly longer 



distally than proximally. 



it'. The proximal cirrus segments bear dorsally a transverse ridge which 



distally becomes a pair of tubercles or small spines, or rarely a single 



median spine; P. is absent; P2 is rounded or rounded prismatic with the 



distal ends of the segments uniformly spinous or smooth (southern 



Japan from Sagami Bay to the Korean Straits southward to the 



Clarence River, New South Wales, and Dirk Hartog Island, Western 



Australia, and westward to east Africa from the Red Sea southward to 



Bagamoyo, Tanganyika Territory [opposite Zanzibar]; 0-137 meters]. 



Decametra (p. 170) 

 k'. Cirrus segments all with a transverse ridge dorsally except for the penulti- 

 mate which bears the opposing spine; P. present (or rarely absent on 

 some arms) ; P2 more or less strongly prismatic with the distal portion 

 of the prismatic ridges on each segment produced into more or less 

 broad finlike processes, or with the distal ends of the prismatic ridges 

 bearing tufts of spines (from Fuchow, Province of Fukien, China, and 

 the Philippine Islands southward to the Tonga Islands, New Caledonia, 

 Port Curtis, Queensland, and Baudin Island, Western AustraUa, and 

 westward to the east coast of Africa from the Red Sea southward to 

 Bagamoyo, Tanganyika Territory ; 0-91 [? 183] meters). 



Oligometra (p. 208) 

 Genus PONTIOMETRA A. H. Clark 



Antedon (part) LCtken, Mus. Godeffroy Cat., vol. 7, 1879, and following authors. 



Pontiometra A. H. Cl.a.rk, Smithsonian Misc. Coll., vol. 50, pt. 3, 1907, pp. 346, 354 (diagnosis; 

 genotype, Anledon andersoni P. H. Carpenter, 1889); Bull. Mus. Comp. Zool., vol. 51, No. 8, 

 1908, p. 247 (same); Proc. Biol. Soc. Washington, vol. 21, 1908, p. 135 (referred to the Himero- 

 metr'idae) ; Proc. U. S. Nat. Mus., vol. 34, 1908, p. 21 1 (same) ; Proc. Biol. Soc. Washington, vol. 

 22, 1909, p. 5 (listed in a revision of the Himerometridae), p. 175 (referred to the Pontio- 

 metridae); Proc. U. S. Nat Mus., vol. 39, 1911, p. 542 (compared with Epimetra); Crinoids of 

 the Indian Ocean, 1912, p. 11 (occurs in the Mergui Archipelago), p. 22 (distribution in detail), 

 p. 57 (in key), p. 138 (original reference; type); Proc. Biol. Soc. Washington, vol. 26, 1913, 

 pp. 141, 143 (referred to the Mariametridae; synonymy; genotype; range; depth; included 

 species)', p. 142 (in key) ; Unstalked crinoids of the Siboga-Eiiped., 1918, p. 97 (in key; range).— 

 Gisl£n,' Zool. Bidrag Uppsala, vol. 9, 1924, p. 51 (obhquity of the brachials), pp. 51, 64, 66 

 724008 — 47 2 



