376 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



b 2 . Cirri with 30 segments; keel on the ossicles of the IBr series lower and more uniform in height; 

 edges of the ossicles of the division series prominently everted (southern Japan; 155 [?115]- 

 365 meters) flavopurpurea (p. 379.) 



PECTINOMETRA CARDUUM (A. H. Clark) 



[See vol. 1, pt. 2, fig. 202 (lateral view), p. 134.] 



Calometra carduum A. H. CLARK, Smithsonian Misc. Coll., vol. 52, pt. 2, 1908, p. 222 (description; 



Albatross station 5167); Proc. U. S. Nat. Mus., vol. 36, 1909, p. 400 (Albatross station 5166). 

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



Unstalked crinoids of the Siboga-Exped., 1918, p. 138 (in key; range). 



Diagnostic features. The ossicles of the division series and the first two brachials 

 have no trace of a median carination: they are coarsely rugose on the dorsal surface, 

 and their sides, which are closely appressed against those of their neighbors, are finely 

 crenulate or dentate and not everted; there are 15-20 arms, and the cirri have 26-40 

 segments. 



Description. The centrodorsal is hemispherical or thick discoidal with a large 

 convex polar area bare. The cirrus sockets are arranged in two closely crowded 

 marginal rows. 



The cirri are X-XV, 26-40 (usually 34-36), from 20 mm. to 25 mm. in length. 

 The first segment is short, the following become progressively longer to the fourth or 

 fifth, which is about as long as broad, and remaining similar to about the end of the 

 proximal third of the cirri, after which the length gradually decreases. From the 

 twelfth or fourteenth segment onward prominent blunt dorsal spines are developed. 

 The opposing spine is rather small, arising from the entire dorsal surface of the penulti- 

 mate segment, with the apex terminal. 



The radials are usually concealed by the centrodorsal, but are sometimes partially 

 visible in the interradial angles. The IBrj are short and bandlike, in lateral apposi- 

 tion, with the dorsal surface coarsely rugose and the edges crenulate or more or less 

 dentate. The IBr 2 (axillaries) are triangular, about twice as broad as long, with the 

 dorsal surface rugose and the edges finely crenulate. The IIBr series are 2, resembling 

 the IBr series and, like the latter, in close lateral apposition. 



The 15-20 arms are 60 mm. long. The first brachials are wedge-shaped, longer 

 exteriorly than interiorly, in close apposition interiorly, with the edges sharply crenu- 

 late or dentate. The second brachials are similar. The first syzygial pair (composed 

 of brachials 3+4) is roughly oblong, not quite twice as broad as long. The next 3 

 brachials are oblong, rather more than twice as broad as long, those following becoming 

 more and more wedge-shaped and after about the twelfth triangular, broader than long, 

 then very gradually wedge-shaped again and increasing in length, though even distally 

 the brachials are never quite so long as broad. The arms terminate very abruptly 

 with 3 or 4 very small brachials beyond which the terminal pinnules extend for about 

 3 mm. 



Syzygies occur between brachials 3+4, 13 + 14 to 17 + 18 (in undivided arms 

 usually also 9 + 10), and distally at intervals of 4 muscular articulations. 



The pinnules resemble those of P. flavopurpurea. 



Localities. Albatross station 5167; Philippine Islands; Tawi Tawi group, Sulu 

 (Jolo) archipelago; Observation Island bearing N. 11 W., 5.6 miles distant (lat. 



