52. BULLETIN S2, UNITED STATES NATIONAL MUSEUM 



Diagnostic features —The elements of the IBr series and the brachials in the 

 proximal third of the arm each bear a narrow rounded median keel which on the first 

 brachial may bo reduced to a prominent tubercle, and the outer edges of the elements 

 of the IBr series and the first two brachials are bordered with a row of thickly set 

 tubercles or small spines. 



Characters. — This form is in general similar to C. gracilicirra gracilicirra, but the 

 broad IBr series and first two brachials, instead of just coming into apposition later- 

 ally and showing only a trace of lateral flattening, are sharply flattened against their 

 neighbors, and their outer edges along the line of contact are strongly everted and 

 strongly denticulate. The radials bear an abrupt rounded dorsoventrally elongate 

 median tubercle. The IBr series have an abrupt more or less tuberculated median 

 ridge which is continued on to the arm bases, becoming less noticeable as the brachials 

 become triangular, but traceable to the distal portion of the arm. There is only a 

 sHght suggestion of this in C. gracilicirra gracilicirra. 



The color pattern is the same as that in the specimens of C. gracilicirra gracilicirra 

 at hand, but the color is much deeper. 



Localities.- — Albatross station 5355; North Balabac Strait, Philippine Islands; 

 Balabac Ught bearing S. 61° W., 16.6 miles distant (lat. 8°08'10" N., long. 

 117°19'15"E.); 80 meters; coral sand; January 5, 1909 [A. H. Clark, 1911,1912,1918] 

 (3, U.S.N.M., 27493 [type], 35307, 35368). 



Albatross station 5356; North Balabac Strait; Balabac light bearing S. 64° W., 

 15.5 miles distant (lat. 8°06'40" N., long. 117°18'45"E.); 106 meters; sand and 

 sheUs; January 5, 1909 [A. H. Clark, 1911, 1912, 1918] (3, U.S.N.M., 35333, 35364). 



Geographical range. — Only known from Balabac Strait, between Palawan and 

 Borneo. 



Bathymetrical range. — From 80 to 106 meters. 



History. — This form was first described as Oligometra gracilicirra var. ornata in a 

 paper published by me in 1911 on a third consignment of crinoids received from the 

 Albatross during the course of her explorations in Pliilippine waters. In addition 

 to the type specimen, two specunens were recorded from station 5355, and two 

 similar specimens from station 5356. Oligometra gracilicirra var. ornata was fisted 

 with the synonymy and habitat and depth of the type locaUty in my memoir on the 

 crinoids of the Indian Ocean published in 1912. In my report on the unstalked crinoids 

 of the Siboga expedition pubUshed in 1918, I included ornata in the key to the species 

 of the genus Cotylometra, giving as the habitat Philippine Islands. 



Genus AUSTROMETRA A. H. Clark 



Oligometra (part) H. L. Clark, Mem. Australian Mus., vol. 4, pt. 11, 1909, p. 522. 



Oligomelrides (part) A. H. Clark, Die Crinoiden der Antarktis, 1915, p. 167. 



Austrometra A. H. Clark, Journ. Washington Acad. Sci., vol. 6, No. 5, 1916, p. 115 (diagnosis; 

 genotype Oligovielra thetidis H. L. Clark, 1909; most closely related to Analcidomeira and 

 Oligomelrides); Unstalked crinoids of the Si6o30-Exped., 1918, p. Ill (in key;range). — Gisl^n, 

 Zool. Bidrag Uppsala, vol. 9, 1924, pp. 84, 90 (articulation in the IBr series), p. 94 (expansion of 

 the pinnule segments), p. 100 (pinnule articulations); Kungl. Fysiogr. Sallsk. Handl., new 

 ser., vol. 45, No. 11, 1934,'p. 18.— H. L. Clark. Echinoderm fauna of Australia, 1946, p. 48 

 (in key), p. 50. 



Diagnosis.— k genus of Colobometridae including small species with 10 arms 

 about 25 mm. long in which the third-fifth segments of the genital pinnules are 



