98 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



Crotalometra magnicirra A. H. CLARK, Proc. Biol. Soc. Washington, vol. 22, 1909, p. 80 (compared 

 with C. rustica); Proc. Biol. Soc. Washington, vol. 22, 1909, p. 147 (related to C. sentifera); 

 Proc. U. S. Nat. Mus., vol. 40, 1911, p. 5 (identity), p. 8 (locality), p. 36 (synonymy; localities 

 in detail); Smithsonian Misc. Coll., vol. 61, No. 15, 1913, p. 45 (published references to specimens 

 in the B. M.; stations 12792 and 12885/6; characters of the cirri and centrodorsal) ; Die Crinoiden 

 der Antarktis, 1915, p. 164 (represents the family Thalassometridae in South Africa; range); 

 Unstalked crinoids of the Siboga-Exped., 1918, p. 149 (in key; range), p. 150 (synonymy). 

 H. L. CLARK, Ann. South African Mus., vol. 13, pt. 7, No. 12, 1923, p. 234 (synonymy: locality). 

 GiSLfiN, Ark. Zool., vol. 19, No. 32, Feb. 20, 1928, p. 8 (C. marginalis probably a large specimen 

 of this species). A. H. CLARK, John Murray Exped. 1933-34, Sci. Reports, vol. 4, No. 4, 1936 

 (January 1937), p. 101 (range), p. 105. GISLN, Kungl. Svenska Vet.-Akad. Handl., ser. 3, 

 vol. 17, No. 2, Oct. 3, 1938, pp. 4, 17 (localities; notes). 



Diagnostic features. The brachials of the middle and outer portions of the arms 

 have the distal edges unmodified, or at least not conspicuously modified. The 16-20 

 (usually 20) arms are 75-110+ mm. long, and the cirri are 55-70 mm. long with 50-63 

 segments. 



Description. On the centrodorsal the cirrus sockets are arranged in 10 columns, 

 with the two columns in each radial area separated from each other by a midradial 

 furrow. 



The cirri are XV-XXV, 50-63, from 55 to 70 mm. long; the eighth or ninth is a 

 transition segment. 



The IIBr series are 4(3+4), exceptionally 2. The margins of the elements of 

 the IBr series may be smooth or everted and finely denticulate; these ossicles may 

 have an indistinct longitudinal carination. 



The 16-20 (usually 20) arms are from 75 to 110+ mm. long. 



Notes. This species has never been adequately described, and no specimens are 

 available for redescription. The description given above was compiled from scattered 

 notes, chiefly by Professor Gisleii. 



Bell's original description was as follows: 



This species appears to stand next to A. [Adelometra] angustriadia of Carpenter's classification, 

 for there are three distichals [IIBr series] not succeeded by palmars [IIIBr series], and the cirri are of 

 great length, but not in as many as ten vertical rows, nor is the distichal pinnule [Pn] larger than the 

 rest. 



The centrodorsal is high, with three or four vertical rows of sockets, the cirri may be as much 

 as 70 mm. long, and the joints 60-80 in number; the most proximal one very short, the next much 

 longer, their successors broad and flattened from side to side, the distal 40 are keeled. The proximal 

 arm joints are fairly rectangular, the rest are narrower, alternately, on one side than the other; no 

 pinnules are very long, but they are all stout. 



Length of arm about 100 mm. Colour, cream yellow. 



In the British Museum I examined 6 specimens under Nos. 12885/6 and 1 under 

 No. 12792. The cirri are XV-XXV, 60-63; the eighth or ninth is a transition seg- 

 ment. The cirrus sockets are arranged in 10 columns, the two columns in each radial 

 area being separated from each other by a midradial furrow. 



A specimen from 20 miles NW. 1/2 N. of East London, according to Gislen, is 

 small; the centrodorsal is dorsally spinous; there are 39 cirrus segments; the elements 

 of the IBr series have an indistinct longitudinal crest but are otherwise smooth; the 

 10 arms are about 75 mm. long. Another specimen from the same locality is larger; 

 there are 50 cirrus segments; the margins of the elements of the IBr series are everted, 



