A MONOGRAPH OF THE EXISTING CRINOIDS 409 



species of the second group range far to the eastward into Polynesia, southward to 

 northern Australia, and westward to east Africa. 



The species of Stephanometra are all inhabitants of shallow water and are most 

 numerous in a narrow band just below the low tide mark. All the species are of medium 

 or rather large size. 



History. — The genus Stephanometra was established by me in 1909, with the 

 genotype Antedon monacantha Hartlaub, 1890. The included forms had previously 

 been placed in the genus Himerometra established in 1907. There has been no change 

 in the status of the genus since its first description. 



KEY TO THE SPECIES AND SUBSPECIES OF THE GENUS STEPHANOMETRA 



a 1 . Outer cirrus segments with long and prominent dorsal spines. 



6 1 . 33-40 (usually 30-35) arms 110-170 mm. long; cirri with 25-37 segments (Philippines south- 

 ward to Paternoster Islands and westward to "India" [possibly Ceylon]; 0-38 



meters) echinus (p. 409) 



b-. 16-24 arms 60-70 mm. long; cirri with 20 segments (Philippines to New Britain, and westward 



to Ceylon; 0-48 meters) tenuipinna (p. 413) 



a 1 . Outer cirrus segments without dorsal spines, being merely slightly carinate dorsally. 



b 1 . Pi stiffened and spinelike, resembling P 2 but somewhat smaller; 12-32 arms 35-150 mm. long; 

 cirri with 15-23 segments (Borneo southward to the Moluccas and Kei Islands; 0-245 



meters) spinipinna (p. 415) 



V. Pi flexible, flagellate, delicate, and slender, much smaller and weaker than the enlarged and 

 stiffened Pj. 

 c 1 . P 2 the only pinnule enlarged and stiffened. 



d'. P 2 much enlarged and stiffened, usually more or less straight, distally ending somewhat 

 abruptly in a strong stout point, composed of 11-15 (usually 12) segments, of which 

 the fourth and fifth are typically abruptly longer than the others (Macclesfield Bank 

 and Philippines to Caroline and Marshall Islands, Samoa, Fiji, Tonga Islands, New 

 Caledonia, and Torres Strait, and westward to Ceylon and Maldive Islands; 0-51 



meters) indica protectus (p. 443) 



d 1 . P 2 somewhat less enlarged and stiffened, usually more or less strongly recurved, distally 

 becoming very slender and delicate, though not flagellate, composed of 15-20 segments 

 of which the fourth and fifth are not noticeably different from the rest (Madagascar, 

 Seychelles, and Red Sea to Ceylon; Torres Strait; 0-62 [?73] meters). indica indica (p. 436) 

 e ! . P 3 and sometimes one or more of following pinnules enlarged and stiffened like P 2 , though 

 usually shorter. 

 d 1 . P 2 and P 3 the only pinnules enlarged, stiffened, and spinelike, P« being short and flexible 

 like the succeeding pinnules (Macclesfield Bank and Philippines to Pelew and Caro- 

 line Islands, New Guinea, the Admiralty and Solomon Islands, Fiji, New Caledonia, 



and Torres Strait, and westward to Red Sea; 0-38 [?64] meters) spicata (p. 424) 



d ! . P,, or P 4 and P s , stiffened and spinelike, resembling P 2 and P 3 though smaller (Philippines 

 to Solomon Islands and Moluccas, and westward to Java; 0-16 [?23] meters) 



ozyacantha (p. 418) 



STEPHANOMETRA ECHINUS (A. H. Clark) 



Plate 45, Figures 205-207; Plate 46, Figures 210, 211; Plate 47, Figures 212-216 



[See also vol. 1, pt. 2, fig. 125 (arm base), p. 79; fig. 273 (arm and pinnules), p. 207; figs. 467, 468 



(pinnule tip), p. 266.] 



Himerometra echinus A. H. Clark, Smithsonian Misc. Coll., vol. 52, 1908, p. 218 (description; 

 Albatross station 5147). 



208244— -40 27 



