PART 5 A MONOGRAPH OF THE EXISTING CRINOIDS 669 



longer earlier segments are two to three times as long as broad and the distal are about 

 as long as broad; the lower bracliials have the distal borders abruptly and strongly 

 everted and spinous; Pi is elongated and exceedingly slender with 20 to 25 segments, of 

 which not more than three or four of the basal ones are as broad as long; P2 is much 

 shorter with many fewer segments; there is no marsupium on the genital pinnules of the 

 female. 



Type species. — Trichomelra aspera A. H. Clark, 1908, a synon3Tii of Antedon cubensis 

 Pourtalds, 1869. 



Oeographical range. — From the eastern part of the Gulf of Mexico and northern 

 Cuba northward to Davis Strait, eastward to south of Iceland and the Faroe Islands 

 and southwards to Portugal ; also from the Hawaiian Islands. 



Bathymetrical range.—From 256 (?252) to 2193 meters. 



Thermal range.— From 2.40° C. to 15.67° (?15.83°) C. 



Remarks [by A.AI.C.]. — The species Bathymetra minutissima A. H. Clark, though 

 named Trichometra bj' Mr. Clark in 1918 and 1940, is placed in the genus Thaumatometra 

 in the typescript, with the name Trichometra erased. Though this was probably done 

 some 3'ears previous to 1940, I believe it represents Mr. Clark's considered opinion and 

 certainly minntissima conforms more to the diagnosis of Thaumatometra as it stands. 

 I have accordingly left it within that genus. 



KEY TO THE SPECIES OF TRICHOMETRA 



a'. More than 40 cirrus segments; cirri XL-LX, 40-45, 20 mm. long, the last 15-20 segments about 

 as long as broad; arms 60-65 mm. long; I Br series and lower brachials narrow, entirely free 



laterally (Hawaiian Islands; 256 [?252]-590 [?648] meters) vexator (p. 669) 



a*. 25-35 cirrus segments. 



b'. Elements of the IBr series and first two brachials only .slightly convex dorsally and sharply and 

 broadly flattened against their neighbors; arms up to 65 mm. long; cirri with 25-35 segments, 

 15-22 mm. long; P, with 20-25 segments, 6 mm. long; Pj with 10 segments, 4 mm. long (from 

 the eastern part of the Gulf of Mexico and northern Cuba northward to Davis Strait, thence 

 eastward to south of Iceland and to the Faroe Islands; 293-2193 meters).. cubensis (p. 671) 

 6*. Elements of the IBr series and first two brachials strongly convex dorsally and laterally, just 

 in lateral contact with their neighbors but not flattened against them; arms 30-40 mm. long 

 in the three specimens detailed; cirri with 27-33 segments; Pi with 21-23 segments; Pj with 

 13 segments, and half as long as Pi (from the coast of Portugal and the Bay of Biscay to south- 

 west of Iceland; 960-2075 meters) delicata (p. 676) 



TRICHOMETRA VEXATOR A. H. Clark 



[See vol. 1, pt. 1, fig. 220, p. 243] 



Trichomelra vexator A. II. CL.tBK, Proc. Biol. Soc. Washington, vol. 21, 1908, p. 132 (^nomen nudum); 

 Proc. U.S. Nat. Mus., vol. 34, 1908, p. 213 (in key), p. 217 (description), p. 218 (.4!6o<ross stations 

 3859, 3865, 3883, 3910, 3925 [type locality], 4105); Smithsonian Misc. Coll., vol. 52, pt. 2, 1908, 

 p. 232 (compared with T. [Fariomelra] explkata); Bull. Mus. Hist. Nat., Paris, No. 4, 1911, p. 

 259 (arms compared with those of T. delicata) ; Crinoids of the Indian Ocean, 1912, p. 240 (synony- 

 my; Hawaiian Is., 138-355 fms.); Unstalked crinoids of the Siboga-Exped., 1918, p. 246 (in key; 

 range), p. 247 (references). 



Diagnostic features.— T]v.s species is easily distinguished from all the others in the 

 genus by the relatively larger number of cirrus segments combined with the narrow IBr 

 series and arm bases which arc not in lateral contact. 



Description. — The centrodorsal is subconical, about twice as broad as high, bearing 

 from 40 to 60 cirrus sockets which are closely crowded and without definite arrangement; 

 there is a moderately large bare polar area. 



