A MONOGRAPH OF THE EXISTING CRINOIDS 73 



i 2 . Cirrus segments either without dorsal processes, or the distal each with a 



median carination or carinate spine. 



j 1 . Gonads developed wholly in the pinnules (vol. 1, pt. 2, figs. 281, 282, p. 215; 

 fig. 298, p. 221; figs. 1056, 1063, 1064, pi. 14) (universal in occurrence; 



found at all depths) Antedonidae (pt. 5). 



? 2 . Gonads lying on the arms at the base of the pinnules (vol. 1, pt. 2, pi. 55; 

 (shores of the Antarctic Continent and immediately adjacent regions; 



shallow to moderately deep water) Notocrinidae (pt. 5). 



Q-. More than 10 arms. 

 h l . Radials 5 in number. 



1 1 . Cirrus segments each with a pair of dorsal spines or tubercles, one on either 



side of the median line (Japan and Polynesia to Australia, westward to the 

 Sunda Islands; littoral and sublittoral) Colobometridae (pt. 4). 



1 2 . Cirrus segments without dorsal processes, or the outer each with a median 



carination or spine. 



j l . Centrodorsal a more or less thick disk with inwardly sloping sides and a 

 broad bare dorsal pole; cirri marginal, and if arranged in more than one 

 row the rows are very irregular. 



fc 1 . IIBr series invariably 2 (vol. 1, pt. 2, figs. 125, 130, p. 79; figs. 194-197, 

 p. 120 and following) (Japan and Polynesia to tropical Australia, west- 

 ward to east Africa; littoral and sublittoral)-- Mariametridae (pt. 4). 

 k~. Some or all of the IIBr series 4 (3 + 4) (vol. 1, pt. 2, fig. 123, p. 79) (Japan 

 and Polynesia to tropical Australia, westward to east Africa; littoral 



and sublittoral) Himerometridae (pt. 4). 



j*. Centrodorsal conical with more or less swollen sides, bearing cirri of decreas- 

 ing size to the apex; cirri arranged in definite columns or in regular alter- 

 nating rows (East Indies and Madagascar; sublittoral). 



Antedonidae (pt. 5). 

 h 2 . Radials 10 in number (shores of the Antarctic Continent and immediately 



adjacent regions; shallow to deep water) Antedonidae (pt. 5). 



f 2 . No pinnules on the lowest 10 or 12 brachials; first syzygial pair, composed of brachials 

 3 + 4, very obliquely wedge-shaped; immediately following brachials triangular; 

 Centrodorsal conical; cirrus sockets, which are arranged in 10 or 15 columns, bordered 

 ventrally by a horseshoe-shaped ridge or flanked by high angular elevations (Japan 

 and Polynesia to the Indian Ocean; Caribbean Sea to Brazil; northeast Atlantic; 



deep water) Atelecrinidae (pt. 5). 



cP. Ventral surface of the outer pinnules protected by prominent side and covering plates 

 easily seen with a hand lens, especially if the pinnule be dried (vol. 1, pt. 2, pp. 399, 405, 

 412; figs. 1166-1169, 1171, pi. 27); pinnules stiffened, with a sharp dorsal crest, triangu- 

 lar in cross section (vol. 1, pt. 2, fig. 659, p. 329). 



'. PI very delicate, flexible and weak, with the first 2 segments enormously enlarged and 

 the remainder very small and about as long as broad; P 2 and usually also some of the 

 following pinnules much elongated, enlarged and stiffened, composed of much 

 elongated segments (vol. 1, pt. 2, fig. 311, p. 223; figs. 314, 320, p. 227); disk globose, 

 compact, entirely inclosed by a complete pavement of plates and readily detached 

 (vol. 1, pt. 2, figs. 734-737, p. 349); color usually variegated, with the arms con- 

 spicuously and regularly banded (vol. 1, pt. 2, figs. 200-202, p. 130 and following) 

 (Japan and Polynesia to tropical Australia and the Bay of Bengal; sublittoral). 



Calometridae (pt. 4). 



