60 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



COSMIOMETRA WOODMASONI (Bell) 



Antedon wood-masoni BELL, Journ. Linn. Soc. (Zool.), vol. 24, No. 154, May 5, 1893, p. 340 (descrip- 

 tion; Sahul Bank), pi. 23; pi. 24, fig. 1. [BELL], Crustacea, Echini, Peripatus, Worms, and An- 

 thozoa, 1906, p. 747. 



Thalassometra wood-masoni A. H. CLARK, Smithsonian Misc. Coll., vol. 50, pt. 3, 1907, p. 360 (listed). 



Cosmiometra woodmasoni A. H. CLARK, Proc. Biol. Soc. Washington, vol. 22, 1909, p. 17 (listed); Proc. 

 U. S. Nat. Mus., vol. 39, 191], p. 549 (compared with C. philippinensis);vol. 40, 1911, p. 38 (com- 

 pared with C. gardineri); Mem. Australian Mus., vol. 4, 1911, p. 795 (synonymy; Sahul Bank); 

 Crinoids of the Indian Ocean, 1912, p. 214 (synonymy; locality); Smithsonian Misc. Coll., vol. 

 61, No. 15, 1913, p. 44 (published reference to specimen in the B. M.; locality; comparison with C. 

 crassicirra); Unstalked crinoids of the Siboga-Exped., 1918, p. 154 (in key; range), p. 155 (ref- 

 erences). 



Diagnostic features . A species with 20 arms in which the elements of the division 

 series and first two brachials are entirely smooth dorsally with a narrow and moderately 

 high median carination and the lateral edges not produced; and the short and rather 

 stout cirri have 40^11 segments. The arms are 110 mm. long, and the cirri are 27 mm. 

 in length. 



Description. Professor Bell's description of this species is as follows : 



This new species belongs to Carpenter's Spinif era-group ; that is, it is bi-distichate [with the II Br 

 series 2] and has some of the basal joints more or less wall-sided. As it has more than thirty cirrus- 

 joints, the more distal of which are spiny, the first pinnule as long as or longer than the second, and 

 the cirri not arranged in rows on the centro-dorsal, it stands nearest to A. [Horaeometra] duplex (P. 

 H. C. MSS) and A. [Stiremetra] lusitanica. The former of these has from 30-40 cirrus joints, the 

 latter 50; the present would appear to have from 35 to 45; the radial axillaries [IBr 2 ] are short and wide 

 as in A. lusitanica, and there is no noticeable expansion of any of the joints of the pinnules. 



The following may serve as a specific diagnosis: 



A member of the Spinifera group, and falling under the same subdivision as A. duplex and A. 

 lusitanica. Centrodorsal rather large, but not columnar, the central portion free of cirrus-sockets; 

 about 18 [XVIII] cirri, with 35-45 joints; these begin to be spiny at about the tenth joint, and the 

 spine, though not large, is quite well marked. First radials [radials] hidden, the second [IBrj] much 

 wider than long, slightly concave on its distal side; the axillaries [IBr 2 ] wide, with two slight concavities 

 for the reception of the first distichal [IIBri], which again is much wider than long; the distichal axillary 

 [IIBr 2 ] of much the same shape as the radial [IBr 2 ]; the two visible radials [ossicles of the IBr series] 

 and the distichals [IIBr series] have a median linear tubercle. 



20 arms. Basal joints with fairly regular sides; the third a syzygy [a syzygy between brachials 

 3 + 4]; then one, ordinarily, on the 12th [between brachials 13+14] or 14th [between brachials 15+16] 

 joints. The arm-joints gradually become triangular, flattened from side to side, and provided with a 

 median ridge. The pinnules are styliform, but short and with simple joints; they increase somewhat 

 in length nearer the end of the arm. 



Diameter of disk 6 millim. Length of arms 1 10 millim. 



Colour white, with faint patches of brown here and there. 



I examined the type specimen at the British Museum in London in 1910. The 

 arms are 110 mm. long, and the cirri are comparatively short and stout, 27 mm. long 

 with 40-41 segments of which the seventh is a transition segment. In my notes I 

 wrote that in general this species resembles C. crassicirra from the Hawaiian Islands; 

 the division series are strongly, but roundedly, carinate. In my diagnosis of Cosmio- 

 metra gardineri I said that it is closely related to C. woodmasoni, but the cirri are shorter 

 and stouter, with proportionately shorter segments ; the carination of the division series 

 is narrower, and the lower brachials have only a faintly indicated crest; the distal 

 brachials are overlapping and narrowly carinate. In my description of Cosmiometra 

 philippinensis in 1911 I noted that this species differs from it in the greater compression 



