PART 5 A MONOGRAPH OF THE EXISTING CRINOIDS 507 



the general surface which are equal in width to about half the transverse diameter of 

 the cirrus sockets ; the cirrus sockets are arranged in 3 closely crowded columns in each 

 radial area; the cirri are long with numerous (about 60) segments, of which the longest 

 proximal are from two and a half to three tunes as long as broad and the last 20 or 

 more are broader than long with prominent dorsal spines; the elements of the IBr 

 series are not hi lateral contact; these ossicles and the earlier brachials have conspic- 

 uously spiny borders; and ah 1 the pinnules are present. 



Type species. Zenometra triserialis A. H. Clark, 1908. 



Geographical range. The Hawaiian and Nicobar Islands. 



Bathymetrical range. One record, 351-643 meters. 



Thermal range.- Between 18.11 C. (at 351 meters) and 5.72 C. (at 643 meters). 



KEY TO THE SPECIES OF SARAMETRA 



a 1 . Cirri about LXXV, arranged in three columns in each radial area; PI and P 2 both with 22 seg- 

 ments (Hawaiian Islands; 351-643 meters) triserialis (p. 507) 



a*. Cirri about CXL, arranged in three or four columns in each radial area; PI with 17 segments, 

 P 2 with only 15 segments (off the Nicobar Islands) nicobarica (p. 508) 



SARAMETRA TRISERIALIS (A. H. Clark) 



[See vol. 1, pt. 1, figs. 109 (p. 175), 214 (p. 241), 377 (p. 301); pt. 2, figs. 300 (p. 221), 801(p. 378)] 



Zenometra triserialis A.H. CLARK, Proc. U.S. Nat. Mus., vol. 34, 1908, p. 213 (in key), p. 2 1 9 (descrip- 

 tion; Albatross sta. 4122); Smithsonian Misc. Coll., vol. 52, pt. 2, 1908, p. 233 (Hawaiian species) ; 

 Crinoids of the Indian Ocean, 1912, p. 234 (synonymy; locality). 



Sarametra triserialis A. H. CLARK, Journ. Washington Acad. Sci., vol. 7, 1917, No. 5, p. 129 (listed); 

 Unstalked crinoids of the Siboga-Exped., 1918, p. 231 (references); Smithsonian Misc. Coll., 

 vol. 72, No. 7, 1921, pi. 2, fig. 26 (ambulacra! deposits); Journ. Linn. Soc. (Zool.), vol. 36, No. 

 249, 1929, p. 661 (compared with S. nicobarica) ; Mem. Soc. Cubana Hist. Nat., vol. 14, No. 2, 

 1940, p. 140. 



Diagnostic features. The cirri are about LXXV, arranged in three columns in 

 each radial area; P t is 8 mm. long with 22 segments; P 2 also has 22 segments but is 

 stouter and 10 mm. long. 



Description. The centrodorsal is elongate conical, 3.5 mm. broad at the base and 

 6 mm. high, with its sides divided into 5 radial areas by 5 interradial lines equal in 

 width to about half the diameter of the adjacent cirrus sockets which are not raised 

 above the general surface. The cirrus sockets are arranged in 3 closely crowded columns 

 of 5 each in each radial area. The apical third of the centrodorsal is thickly covered 

 with short more or less branched spines and bears more or less obliterated cirrus sockets. 



The cirri are about LXXV, 60, rather slender, from 40 to 45 mm. long. The 

 first segment is short, the second is rather longer, the third is about as long as broad, 

 and the following gradually increase in length to the seventh to eighteenth or twentieth 

 which are between two and a half and three times as long as broad; those succeeding 

 gradually decrease in length becoming about as long as broad on or near the thirty- 

 third, and distally broader than long. From the fourth or fifth to the eighth or ninth 

 the segments have their ends somewhat expanded, and the following have the distal 

 dorsal edge rather prominent so that the cirri have a serrate dorsal and smooth ventral 

 profile; in the terminal portion the cirri become moderately compressed, and the 

 dorsal surface of the segments becomes carinate and forms low spines. The opposing 



556-62267 34 



