46 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



from the John Murray Expedition to the Indian Ocean, 1933-34, that had been secured 

 by His Egyptian Majesty's steamer Mabahiss at station 157 in the Maldive region. 



COSMIOMETRA DELICATA (A. H. Clark 



Plate 3, Figure 9 

 [See also vol. 1, pt. 1, fig. 367, p. 297; pt. 2, fig. 214, p. 157. J 



Thalassomelra delicata A. H. Clark, Proc. U. S. Nat. Mus., vol. 34, 1908, p. 214 (in key), p. 225 

 (description; Albatross, station 3963). 



Cosmiometra delicata A. H. Clark, Proc. Biol. Soc. Washington, vol. 22, 1909, p. 17 (listed); Crinoids 

 of the Indian Ocean, 1912, p. 215 (synonymy; locality); Unstalked crinoids of the St'boja-Exped., 

 1918, p. 153 (in key; range), p. 154 (references); Rec. Indian Mus., vol. 34, pt. 4, December 1932, 

 p. 566 (compared with C. leilae). — Gislem, Kungl. Fysiogr. Sallsk. Handl., new ser., vol. 45, 

 No. 11, 1934, p. 25.— A. H. Clark, Bernice P. Bishop Mus. Bull. 195, 1949, p. 74 (Albatross 

 station 3963), p. 97 (station data). 



Diagnostic Jeatures. — A slender species with 28 arms; the cirri, which are slender 

 and rather short and have the transition segment at about the sixteenth, are arranged 

 in 10 definite columns on a rather small rounded conical centrodorsal. The arms are 

 110 mm. in length, and the cirri are 30-35 mm. long with 40 segments. 



Description. — The centrodorsal is rounded conical, rather small. The cirrus sockets 

 are arranged in 10 columns, one, more rarely two, to a column. 



The cirri are XIII, 40, from 30 mm. to 35 mm. long. The first 2 segments are 

 short, the third is not quite so long as broad, and the fourth is rather longer than broad. 

 Tho following segments to between the tenth and fifteenth are about half again as long 

 as broad. The transition segment falls between the tenth and fifteenth, but is usually 

 nearer the latter. The first segment after the transition segment is rather longer than 

 broad and thoso following gradually decrease in length, the terminal being about twice 

 as broad as long. After the transition segment the dorsal distal edge of the segments 

 projects in the form of a sharp transverse ridge which appears as a spine in lateral 

 view. The opposing spine in lateral view is triangular and blunt, and does not reach 

 one quarter the width of the penultimate segment in height. The terminal claw is 

 somewhat longer than the penultimate segment, rather stout, and only moderately 

 curved. 



The disk is thickly plated along the ambulacral grooves, and bears scattered 

 calcareous granules in the interambulacral areas. The brachial ambulacra are rather 

 scantily plated, but side and covering plates are well developed on the pinnules. 

 Sacculi are abundant on the pinnules, but small. 



The ends of the basal rays are visible as tubercles in the interradial angles of the 

 calyx. 



The radials are concealed by the centrodorsal. The IBr, are very short, bandlike, 

 with the borders prominent and with a blunt median keel. The IBr, (axillaries) are 

 rhombic, about twice as broad as long, with rather prominent borders and a strong 

 rounded median keel. The IIBr and IIIBr series are 2, tho latter developed exteriorly 

 in 2, 1, 1,2 order; both resemble the IBr series. The division series and the first 12 

 or 15 brachials are sharply flattened laterally. 



The 28 arms (in the type) are 110 mm. in length. The first 9 brachials are oblong 

 or slightly wedge-shaped, broader than long, those following becoming triangular or 



