A MONOGRAPH OF THE EXISTING CRINOIDS 209 



classed as a Malayan type. On the basis of previous records it was listed by 

 Dr. Hubert Lyman Clark in 1915 as among the echinoderms of Ceylon. 



In 1915 Dr. Hubert Lyman Clark published an account of a specimen which he 

 had collected at Maer Island in Torres Strait in 1913, and in 1916 Dr. Robert Hart- 

 meyer published a correction of a catalogue number on one of the specimens in the 

 Berlin Museum which had been recorded by the author in 1912. 



In the author's report upon the unstalked crinoids of the Siboga expedition pub- 

 lished in 1918 a detailed account of all the specimens referable to this species was given, 

 and many new localities were added to the known range. In 1921 Dr. H. L. Clark 

 discussed the distribution of this species on the coasts of Australia in great detail. 



The specimen of Comaster multijida from Mjoberg's station 1 described and figured 

 by Gislen in 1919, and reidentified by him in 1922 as Comanthus parmcirra, was in 

 reality a young and more or less aberrant example of this species. 



CAPILLASTER TENUICIRRA A. H. Clark 



Plate 15, Figure 37 



Capillaster tenuicirra A. H. Clark, Proc. Biol. Soc. Washington, vol. 25, 1912, p. 18 (description; 

 Siboga Station 320); Unstalked Crinoids of the Siboga Exped., 1918, p. VIII (discovery by 

 the Siboga and its significance); p. 10 (in key; range); p. 12 (synonymy; detailed description; 

 Stations 166, 318, 319, 320); pp. 273, 276 (listed); pi. 12, fig. 6. 



Diagnostic features. — Except for the elongated and slender cirri in which the 

 distal segments from the tenth or eleventh onward are very slightly longer than 

 broad, this species resembles C. mult ir ad lata. The arms are 14-32 (usually 20-25) 

 in number, and the cirri are XII, 24-30. 



Description of a specimen from Siboga station 166. — The centrodorsal is thick 

 discoidal, rather small, with the bare polar area flat, 3 mm. in diameter. The cirrus 

 sockets are arranged in a single irregular marginal row. 



The cirri are XII, 24-27, 25 mm. long. The first segment is very short, the 

 second and third are about twice as broad as the ventral length, the fourth is half 

 again as long as broad, the fifth is twice as long as broad, the sixth resembles the 

 fifth, and those following gradually decrease in length so that the tenth or eleventh 

 and those following are very slightly longer than broad. The sixth is a transition 

 segment. The cirri taper slightly from the base to the middle of the transition 

 segment, from that point onward being more slender and highly polished. Fi-om the 

 transition segment onward the segments have the distal dorsal edge slightly everted, 

 forming a low and inconspicuous transverse ridge just within the distal dorsal border 

 which is narrowly crescentic in end view, never becoming pointed. This is so low 

 as to be almost imperceptible in lateral view, so that the cirri superficially appear 

 quite smooth. The opposing spine is very small, terminal. The terminal claw is 

 slightly longer than the penultimate segment, moderately slender and moderately 

 and evenly curved. 



The ends of the basal rays are just visible in the angles of the calyx, bridging 

 over the narrow subradial clefts. 



The IBri are very narrow, trapezoidal, about five times as broad as long, entirely 

 united laterally. The IBr2 (axillaries) are very broadly pentagonal, twice as broad 

 as long, free laterally. The IIBr series are 4 (3 + 4). 



