A MONOGRAPH OF THE EXISTING CRINOIDS 91 



under the genus, with the synonymy and ranges, C. eupedata, C. propinqua, C. valida, 

 and C. incerta, accepting Crotalometra in the sense of its formal description instead of 

 its first appearance. Under Thalassometra were listed Th. magnicirra, Th. rustica, Th. 

 sentifera, and Th. infelix, herein referred to Crotalometra. In a paper on the crinoids of 

 the British Museum published in 1913 there appears the heading "Genus Aglaometra 

 A. H. Clark" under which are given notes on Aglaometra valida and A. incerta. 



The genus Aglaometra is inserted in a key to the genera of the subfamily Thalasso- 

 metrinae in my memoir on the unstalked crinoids of the Siboga expedition, and a key to 

 the included species (vera, propinqua, sulcata, eupedata, valida, and incerta) is given. 

 These 10-armed forms are therefore definitely removed from the genus Crotalometra, 

 which in the Siboga report is given as including C.flava, C. porrecta, C. sentifera, C. rus- 

 tica, C. marginalia, and C. magnicirra. Since the publication of the Siboga report the 

 status of the genus Crotalometra has remained unchanged. In the present work the 

 two Atlantic species, porrecta and flam, which differ markedly from the Indo-Pacific 

 forms, are set apart as constituting the new genus Koehlermetra. 



KEY TO THE SPECIES IN THE GENUS CROTALOMETRA 



o'. Brachials beyond the proximal third of the arms with the central portion of the distal dorsal edge 

 produced into long overlapping spines which are more or less flattened dorsoventrally and 

 rounded or truncate at the tip; 12-19 arms 150-160 mm. long; cirri 40-50 mm. long with 51-62 



segments (Maldive and Laccadive Islands; 914-1,265 meters) sentifera (p. 91) 



a j . Brachials beyond the proximal third of the arms not produced into long overlapping dorsal spines. 



6'. Brachials beyond the proximal third of the arms strongly overlapping, the central portion of the 



distal dorsal edge somewhat produced and spinous; 13-20 arms 90-150 mm. long; cirri 55-85 



mm. long with 45-70 segments (Moluccas and the Malay Archipelago to Formosa and Madras; 



55-2,047 meters) rustica (p. 91) 



ft 2 . Brachials beyond the proximal third of the arms with the distal borders unmodified, or at least 

 not conspicuously modified; 16-20 (usually 20) arms 75-110 + mm. long; cirri 55-70 mm. long 

 with 50-63 segments (southeastern Africa from Durban to Port Elizabeth; 91-731 [?823J 

 meters) magnicirra (p. 97) 



CROTALOMETRA SENTIFERA A. H. Clmrk 



PLATE 32, FIGURES 100-103 



Crotalomelra senlifera A. H. CLARK, Proc. Biol. Soc. Washington, vol. 22, 1909, p. 147 (description; 

 lat. 1047'45" N., long. 7240'20" E., 703 fms.); Proc. U. S. Nat. Mus., vol. 39, 1911, p. 551 

 (compared with C. infelix); Unstalked crinoids of the Sifcoga-Exped., 1918, p. 149 (in key; range; 

 references); Journ. Linn. Soc. (Zool.), vol. 36, No. 249, April 1929, p. 654 (compared with C. 

 eridanella, sp. nov. [ = C. rustica]); John Murray Exped. 1933-34, Sci. reports, vol. 4, No. 4, 1936 

 (January 1937), p. 87 (listed), p. 92 (Mabahiss station 158; notes; range), pp. 98, 101, 103. 



Thalassometra sentifera A. H. CLARK, Crinoids of the Indian Ocean, 1912, p. 201 (synonymy; descrip- 

 tion; locality), fig. 37, p. 202. 



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

 have the central portion of the distal edge produced into long and conspicuous more or 

 less dorsoventrally flattened overlapping spines. The 12-19 arms are 150-160 mm. 

 long, and the cirri are 40-50 mm. long with 51-62 segments. 



Description. The cirri are XX, 59-62, 50 mm. long. 



The 12-16 arms are from 150-160 mm. long. After the proximal third of the arm 

 the brachials bear long overlapping spines which are more or less flattened dorsoventrally 

 and rounded or truncated at the tip. 



