272 BULLETIN 82, UNITED STATES NATIONAL MUSEUM VOLUME 1 



13.5 C.; coarse black sand; October 26, 1906 [A. H. Clark, 1907] (5, U.S.N.M. 22607, 

 35931, 36231). Type locality. 



Geographical range.- Only known from Sagami and Tokj T o Bays, southern Japan. 



Bathy metrical range. From 128 to 360 meters; the average of three records is 256 

 meters. 



Thermal range. From 8.67 to 18.33 C. ; the average of three records is 13.5 C. 



THYSANOMETRA TENUICIRRA (P. H. Carpenter) 



Antedon, sp. P. H. CARPENTER, Proc. Roy. Soc., vol. 28, 1879, p. 384. 



Antedon tenuicirra P. H. CARPENTER, Challenger Reports, Zoology, vol. 26, pt. 60, 1888, p. 186 (de- 

 scription; Challenger Sta. 219), pi. 30, figs. 4-8, pi. 33, figs. 4, 5. A. H. CLARK, Smithsonian 

 Misc. Coll., vol. 50, pt. 3, 1907, p. 353 (listed); Proc. Biol. Soc. Washington, vol. 21, 1908, p. 125 

 (really belongs in Thysanometra; possibly young of Th. tenelloides) ; Crinoids of the Indian Ocean, 

 1912, p. 33 (of P. H. Carpenter, l888 = ~Thysanometra tenuicirra). 



Antedon notata P. H. CARPENTER, Challenger Reports, Zoology, vol. 26, pt. 60, 1888, p. 187 (in text), 

 pi. 33, figs. 4, 5. 



Antedon tennicirra HAMANN, Bronn's Klassen und Ordnungen des Tier-Reichs, vol. 2, Abt. 3, 1907, 

 p. 1579 (listed). 



Thysanometra tenuicirra A. H. CLARK, Proc. Biol. Soc. Washington, vol. 21, 1908, p. 125 (tenuicirra 

 referred to Thysanometra); Crinoids of the Indian Ocean, 1912, p. 244 (synonymy; locality); 

 Smithsonian Misc. Coll., vol. 61, 1913, No. 15, p. 64 (published references to specimens in B.M.; 

 Challenger Sta. 219; characters, and comparison with Th. tenelloides) ; Unstalked crinoids of the 

 Si&ogia-Exped., 1918, p. 218 (in key; range; references; Albatross Sta. 5221). GISLEN, Ark. 

 Zool., vol. 19, No. 32, 1928, p. 10 (notes). 



Diagnostic features. The brachials beyond the second syzygy are triangular, as 

 long as broad, in the outer part of the arm becoming very obliquely wedge-shaped and 

 longer than broad; when the arms are 55 mm. long the cirri are XXX-XL, 15-25; P 2 is 

 about the same length as, or longer than, P! and composed of stouter and more elongate 

 segments. 



Carpenter's description oj the type specimen. The centrodorsal is hemispherical. 



The cirri are XXX or more, long and slender, with 15-25 or more segments of 

 which the first three are very short and the rest much elongated. 



Radials just visible. The IBri are short, rounded and oblong, free laterally, and 

 scarcely incised by the axillaries, which are widely rhombic with open proximal angles. 



The 10 arms are 55 mm. long, and are composed of smooth obliquely quadrate 

 brachials. 



Syzygies occur between brachials 3 + 4 and 9 + 10, and distally at intervals of from 

 3 to 6 muscular articulations. 



The pinnules of the first pair (P] and PJ are long, slender and delicate, composed 

 of numerous segments which are but little longer than broad. Those of the second pair 

 (P 2 and P b ) are of about the same length, but are composed, like their successors, of 

 stouter and more elongate segments, which become slender again in the distal pinnules. 



The disk and ambulacra are naked. Sacculi are moderately abundant. 



Carpenter's notes on a second specimen Jrom the same station. Besides the mutilated 

 individual just described, Challenger station 219 also yielded another which Carpenter 

 at first regarded as representing a distinct species (notata), but later considered would 

 be better interpreted as a varietal form of tenuicirra, although, according to Carpenter, 

 it presents some not unimportant differences. 



The cirri are both more numerous and have a larger number of segments than in the 



