820 BULLETIN 82, UNITED STATES NATIONAL MUSEUM VOLUME 1 



distal border slightly incised; the inner sides of adjacent first brachials just meet over 

 the distal angle of the axillaries, from that point diverging rapidly so as to leave a con- 

 siderable gap between them. The second brachials are irregularly quadrate, with the 

 distal border strongly oblique, and the posterior with a sharp angular projection in- 

 cising the first. The first syzygial pair (composed of brachials 3 + 4) is very obliquely 

 wedge-shaped, over twice as long interiorly as exteriorly. The following brachials 

 are very obliquely wedge-shaped, not quite so long as broad. 



Syzygies occur between brachials 3+4, 6 + 7, 9 + 10, and 12 + 13. 



The only known specimen has no pinnides on the few remaining brachials. 



A striking feature of this species is the conspicuous diamond-shaped aperture 

 in each interradius between the IBr series resulting from the strongly oblique lateral 

 edges of the axillaries and the wide divergence of the inner sides of the first brachials. 



Locality. Albatross station 3887; north coast of Molokai, Hawaiian Islands; 

 Mokuhooniki Islet bearing S. 15 W., 8.8 miles distant; 1009-1479 meters; temperature 

 4.17 C.; globigerina mud; April 17, 1902 [A. H. Clark, 1908] (1, U.S.N.M., 22685). 



ATELECRINUS WYVILLI P. H. Carpenter 



FIGURE 52 

 See also vol. 1, pt. 1, figs. 123 (p. 192), 125 (p. 193); pt. 2, pi. 26, fig. 1164] 



Atelecrinus wyvilli P. H. CARPENTER, Journ. Linn. Soc. (Zool.), vol. 16, 1882, p. 492 (description; 

 Challenger sta. 174). GISLEN, Ark. Zool., vol. 19, No. 32, 1928, p. 13 (syzygies). 



Atelecrinus wyvillii P. H. CARPENTER, Challenger Reports, Zoology, vol. 26, pt. 60, 1888, p. 72 (de- 

 scription; Challenger sta. 174C.), pi. 6, figs. 4, 5. WALTHER, Einleitung in die Geologie als his- 

 torische Wiss., 1894, p. 299 (after Carpenter). A. H. CLARK, Crinoids of the Indian Ocean, 1912, 

 p. 32 (identity), p. 252 (synonymy; locality); Smithsonian Misc. Coll., vol. 61, No. 15, 1913, p. 68 

 (published references to specimens in B.M.; Challenger sta. 174C); Unstalked crinoids of the 

 Siboga-Exped., 1918, p. 267 (in key; range). 



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

 p. 1575 (listed). A. H. CLARK, Notes Leyden Mus., vol. 34, 1912, p. 153 (compared with A. 

 sulcatus) . 



Alelecrinus sulcatus A. H. CLARK, Notes Leyden Mus., vol. 34, 1912, p. 152 (description; Siboga sta. 

 85); Unstalked crinoids of the Sibojo-Exped., 1918, p. 267 (in key; range; detailed description; 

 sta. 85), p. 268 (Albatross sta. 5619), p. 272 (listed); fig. 16, p. 267; pi. 26, fig. 94. 



Diagnostic features. The 10 columns of cirrus sockets are segregated into 5 pairs 

 of columns, one pair in each radial area. These pairs of columns of cirrus sockets 

 are separated from their neighbors by relatively broad naked interradial spaces or 

 shallow grooves. The sockets of the 2 columns in each radial area are quite distinct 

 from each other. There are low, short interradial ridges on the proximal (basal) 

 portion of the centrodorsal, with well-rounded summits. 



Description of the type specimen [modified by A.M.C.]. The centrodorsal is conical, 

 3 mm. broad at the base and 4 mm. high. The cirrus sockets are arranged in 10 columns 

 of 4, rarely 5, each, two in each radial area. The 2 columns in each radial area are well 

 separated from those in the adjoining radial areas by intervening spaces, and do not 

 reach the dorsal pole. The adjacent rows of sockets tend to alternate in level. The 

 proximal (basal) portion of the centrodorsal is uniformly smooth, without any inter- 

 radial ridges; but the edge is marked by 5 slight incisions situated interradially. A 

 pair of prominent, conical, almost vertically directed tubercles borders each cirrus 

 socket laterally, and similar ones cover the apex of the centrodorsal. 



