A MONOGRAPH OF THE EXISTING CRINOIDS 25 



History. This species was first described in February 1936, from a single speci- 

 men collected by Dr. H. Boschma, the biologist of the Willebrord Snellius expedition, 

 at Ternate. On August 11, 1936, it was again described by Dr. Torsten Gislen under 

 the name Rhadinometra dawydovi, new genus and species, from two specimens collected 

 by Dr. C. Dawydoff in Cochin China and Cambodia. 



Genus EPIMETRA A. H. Clark 



Epimetra A. H. CLARK, Proc. U. S. Nat. Mus., vol. 39, 1911, p. 542 (diagnosis; genotype Epimetra 

 nympha); Crinoids of the Indian Ocean, 1912, p. 57 (in key), p. 138 (original reference; type); 

 Proc. Biol. Soc. Washington, vol. 26, 1913, p. 141 (referred to the Colobometridae) ; Un stalked 

 crinoids of the Siboga-Exped., 1918, p. 112 (in key). GISLEN, Nova Acta Reg. Soc. Sci. Up- 

 saliensis, ser. 4, vol. 5, No. 6, 1922, pp. 7, 123. A. H. CLARK, Temminckia, vol. 1, 1936, p. 305. 



Diagnosis. A genus of Colobometridae including small and very slender species 

 in which the arms are about 40 in number and about 50 mm. long; all the division 

 series are 2; the cirri are long and comparatively stout, 12 mm. long with about 40 

 segments of which the longest are slightly longer than broad; dorsally the cirrus seg- 

 ments bear a thin median keel, which may be paired; PI, P 2 , and P 3 are similar, 

 rigid and much elongated with greatly elongated segments, 6-8.5 mm. long with 9-12 

 segments; P 2 is longer and somewhat stouter than P] and P 3 ; P 4 is similar, but shorter; 

 P 4 is always absent, and on the inner arms on each IIBr series P, is also absent. 



The single species of Epimetra suggests a diminutive and very slender Pontio- 

 metra with the pinnulation of a Colobometra. 



Geographical range. Known only from between Palawan and Balabac Islands, 

 Philippines. 



Bathymetrical range. Known only from 106 meters. 



EPIMETRA NYMPHA A. H. Clark 



PLATE 4, FIGURES 11, 12 



Epimetra nympha A. H. CLARK, Proc. U. S. Nat. Mus., vol. 39, 1911, p. 542 (description; Albatross 

 station 5356); Crinoids of the Indian Ocean, 1912, p. 138 (synonymy; locality). GISLEN, 

 Kungl. Fysiogr. Sallsk. Handl., new ser., vol. 45, No. 1, 1934, p. 25. 



Description. The centrodorsal is small, hemispherical, with the dorsal pole 

 convex, 1 mm. in diameter. 



The cirri are XIII (deficient in 2 interradii), 37-39, 12 mm. in length. The 

 first segment is short, and those following gradually increase in length, becoming 

 about as long as broad on the fifth. The succeeding 4 to 6 segments are slightly 

 longer than broad, and the following gradually decrease in length, those in the distal 

 half of the cirri being nearly twice as broad as long. The eighth is a transition seg- 

 ment. The segments following have the distal dorsal edge slightly thickened and 

 produced, and the dorsal surface developing a low narrow median keel which becomes 

 more prominent in the outer part of the cirri so that the dorsal profile of the outer 

 part of the cirri is scalloped. In dorsal view the opposing spine is a thick V-shaped 

 or lobate production of the distal half of the penultimate segment; the 2 limbs of the 

 V are thick proximally, tapering to a fine point at the apex. In end view this op- 

 posing spine is seen as a strong high crescent. 



The radials are strongly produced in the interradial angles of the calyx where 

 they separate the bases of the IB^ for a distance equal to about one-half of their 



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