26 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



dorsal width. The IBr, IIBr, and IIIBr series are all 2, and resemble the correspond- 

 ing series in Pontiometra andersoni, but the component segments are somewhat 

 longer and the synarthrial tubercles are more pronounced. 



The 39 arms are about 50 mm. long and resemble those of Pontiometra andersoni, 

 but the brachials are slightly constricted and have rather prominent ends. 



On the outer arms borne by each postradial series P is absent; on the inner 

 arms P a and usually also PI are absent. PI on the outer arms is 6 mm. long, exceed- 

 ingly slender, with 12 segments which are not quite so long as those of the following 

 pinnule. Pj is 8.5 mm. long, resembling PI but slightly larger and stouter and much 

 stiffer, with 10 segments. P 3 is 6 mm. long, stiffer than PI, with 9 segments which 

 resemble those of P 2 . ?4 is 4.3 mm. long, very slender, with 8 segments all but the 

 first 2 of which are greatly elongated. The following pinnules gradually increase in 

 length, the distal pinnules being 7 mm. long with 12 segments. P b on the inner arms 

 is 9 mm. long with 11 segments of which the first is not so long as broad, the second 

 is half again as long as broad, the third is 3 times as long as broad, and the following 

 are greatly elongated with swollen articulations, the last 2 or 3 having long and very 

 slender spines upon their distal ends; the terminal segment, as usual, is short. The 

 pinnule is exceedingly slender, but stiff and not flagellate. 



Locality. Albatross station 5356; North Balabac Strait, between Palawan and 

 Balabac Island, Philippines; Balabac light bearing S. 64 W., 15.5 miles distant (lat. 

 806'40" N., long. 11718'45" E.); 106 meters; sand and shells; January 5, 1909 

 [A. H. Clark, 1911, 1912, 1918] (1, U. S. N. M., 27492). 



History. As yet this species is known only from the single specimen dredged by 

 the Albatross in 1908 and described by me in 1911. 



Genus CENOMETRA A. H. Clark 



Antedon (part) HARTLAUB, Nachr. Ges. Gottingen, May 1890, p. 174, and following authors. 



Himeromctra (part) A. H. CLARK, Smithsonian Misc. Coll., vol. 50, pt. 3, 1907, p. 356. 



Cenometra A. H. CLARK, Proc. Biol. Soc. Washington, vol. 22, 1909, p. 8 (diagnosis; genotype 

 Himerometra unicornis A. H. Clark, 1908); Vid. Medd. Naturh. Foren. K0benhavn, 1909, 

 p. 174 (included in the Colobometridae), p. 193 (probably occurs at Singapore, though not yet 

 discovered there); Proc. U. S. Nat. Mus., vol. 40, 1911, p. 4 (part of Bell's Antedon emendatrix 

 is a species of this genus), p. 13 (common to southeast Africa and Ceylon, but not occurring in 

 the Arabian Sea), p. 29 (arm division always external), p. 33 (character of Pz) ; Mem. Australian 

 Mus., vol. 4, pt. 15, 1911, p. 730 (in key), p. 732 (in key), p. 735 (1 species in Australia), p. 772 

 (original reference; characters; range); Crinoids of the Indian Ocean, 1912, p. 10 (absent from 

 Japan), p. 11 (represented in the Ceylon region, which is the western limit of the large and 

 highly multibrachiate species), p. 12 (represented in the southeast African region), p. 22 (dis- 

 tribution in detail), p. 58 (in key), p. 153 (original reference; type); Unstalked crinoids of the 

 Siboga Exped., 1918, p. Ill (in key). GisLiiN, Zool. Bidrag Uppsala, vol. 9, 1924, p. 51 (ob- 

 liquity of brachials), p. 84 (syzygies), p. 90 (articulation in the IBr series); Nova Acta Reg. 

 Soc. Sci. Upsaliensis, ser. 4, vol. 5. No. 6, 1922, p. 76; Kungl. Svenska Vet.-Akad. Handl., 

 ser. 3, vol. 18, No. 10, 1940, pp. 13, 14. H. L. CLABK, Echinoderm fauna of Australia, 1946, 

 p. 48 (in key). 



Diagnosis. A genus of Colobometridae including large or medium-sized species 

 with 12-39 arms 85-140 mm. long; the IIBr series are 2; P 2 is very stout, abruptly 

 larger, stouter, and stiffer than P t or P 3 , recurved and hornlike, the 11-23 (usually 

 15-20) segments with produced and spinous distal ends; the cirri are stout and 

 strongly curved with 28-45 segments all of which are much broader than long and 



