380 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



Pectinometra flavopurpurea A. H. CLARK, Crinoids of the Indian Ocean, 1912, p. 188 (synonymy; 

 locality); Journ. Washington Acad. Sci., vol. 5, No. 6, 1915, p. 215 (range and its significance); 

 Unstalked crinoids of the /Si&offo-Exped., 1918, p. 138 (in key; range). GISL&N, Nova Acta 

 Reg. Soc. Sci. Upsaliensis, ser. 4, vol. 5, No. 6, 1922, p. 5 (364-728 meters), p. 5 (Sagami Bay), 

 p. 97 (Bock's stations 34, 35, 36; detailed notes), p. 181 (listed), figs. 72, 73, p. 88; Zool. Bidrag 

 Uppsala, vol. 9, 1924, p. 11 (pinnule replacing arm), pp. 41, 42 (obliquity of brachials), p. 44 

 (arms and pinnules), p. 46 (interior obliqueness of brachials), p. 51 (joint faces), p. 53 (axil- 

 laries), p. 54 (abnormal pinnulation), p. 79 (nonmuscular articulations), fig. 13, p. 45 (ventral 

 view of brachials with the muscles removed), fig. 18, p. 48 (lateral view of brachials), figs. 36, 

 37, p. 52 (articular surfaces of brachials), fig. 40, p. 58 (abnormal pinnulation), figs. 76, 105, 

 166, 167, 300 (articulations); Vid. Medd. Dansk Naturh. Foren., vol. 83, 1927, p. 2 (occurrence 

 of IIBr series; station 26; 360 meters), p. 32 (station 26; notes), p. 69 (listed); Kungl. Fysiogr. 

 Sallsk. Handl., New ser., vol. 45, No. 11, 1934, p. 20. 



Pectiometra flavopurpurea GISL^N, Zool. Bidrag Uppsala, vol. 9, 1924, p. 54 (pinnules and brachial 

 obliqueness), figs. 36, 37, p. 52; figs. 166, 167, p. 98 (pinnule articulation). 



Diagnostic features. The ossicles of the division series bear a prominent median 

 keel which on the IBr series is lower and more uniform in height than in P. magnifica; 

 there are 30 cirrus segments and 20 arms about 70 mm. in length. 



Description. The centrodorsal is low hemispherical with the dorsal pole flat or 

 slightly convex. The marginal cirrus sockets are arranged in 2 closely crowded 

 alternating rows; there are roughly 3 sockets immediately beneath each radial. 



The cirri are XV-XX, 25-30, 15 mm. long. The first 4 segments are about 

 twice as broad as long, the first the shortest and those following gradually increasing 

 in length; the fifth is about as long as broad and those succeeding are of the same 

 length or slightly longer than broad, after the tenth gradually becoming shorter. 

 From the tenth onward the segments are provided with broad and prominent, though 

 blunt, dorsal spines. The opposing spine is low and triangular. The terminal claw 

 is stout, not so long as the penultimate segment, and relatively slightly curved. 



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



The radials are usually concealed by the centrodorsal but are sometimes more 

 or less visible in the interradial angles. The IBr! are short, about four times as 

 broad as long, roundedly carinate, laterally in apposition with their neighbors on 

 either side. The IBr 2 (axillaries) are broadly triangular, twice as broad as long, with 

 the lateral angles produced into more or less of a blunt spine or tubercle. The IIBr 

 series are 2. The IIBr, have a broad flangelike production of the outer edge which 

 just meets that of the IIBri on the adjacent ray and in width is usually equal to about 

 one-third of the width of these ossicles. The IIBr 2 resemble the IBr 2 ; the distal 

 angle is more or less produced. 



The arms are 20 in number, occasionally a few less, about 70 mm. in length. 

 The first brachials are slightly wedge-shaped, exteriorly produced laterally into a 

 thin keel, more especially in the proximal half; this keel is not so large as the lateral 

 processes on the IIBr,. The second brachials are wedge-shaped, convex exteriorly, 

 and of about the same size as the first. The first syzygial pair (composed of brachials 

 3+4) is about as long as broad, with the distal edge somewhat everted and finely 

 spinous. The next 2 brachials are oblong, about twice as broad as long, those follow- 

 ing quickly becoming triangular and about as long as broad. The terminal brachials 

 fall about 4 mm. short of the tips of the distal pinnules. All of the brachials overlap 



