g BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



c> No broadening or expansion of the genital pinnules, which are slender and evenly tapering. 



d' P, and P. absent; cirri with 12-19 segments of which the second and third are about as 

 long as broad and the fourth is longer than broad, but the distal are shorter; fifth-seventh 

 or -eighth segments with a low curved transverse ridge, those following with a small 

 simple dorsal tubercle; 10 arms 12-35 mm. long (southwestern Mindanao, Philippines, 

 to the Boniu Islands; 72-80 meters) Clarkometra (p. 246) 



d\ Pi always present, at least on the outer arms of a postradial series; P. may or may not be 



present, 

 e'. Distal edges of the proximal cirrus segments fringed with spines; cirri with 29-65 seg- 

 ments of which the distal are shorter than the proximal, much broader than long, and 

 bear dorsally prominent paired, or rarely single, dorsal spines; one or more pairs of 

 the proximal pinnules elongated, much stiffened, and composed of elongated segments 

 with very spiny distal ends; segments of all the pinnules and the brachials with spiny 

 distal ends; 10 arms 40-170 mm. long (from the Philippine Islands and Singapore 

 southward to the Solomon Islands, Lord Howe Island, and Port Denison, Queensland, 



and westward to the Red Sea; 0-106 meters) Colobometra (p. 116) 



€'. Distal edges of all the cirrus segments smooth. 



/'. Cirrus segments beyond the proximal fourth of the cirri with long median unpaired 



dorsal spines; proximal pinnules short, P2 the largest, with not more than 13 rather 



short segments with spinous distal ends; cirri with 24-39 segments; 10 arms 20-80 



mm. long (from the Philippine to the Kei and Andaman Islands; 80-113 meters). 



Cotylometra (p. 48) 

 /'. Outer cirrus segments dorsally with a transverse ridge or paired tubercles or short 

 spines, sometimes with a median tubercle or spine on one or two before the penulti- 

 mate, 

 ffi. Cirrus segments with two dorsal transverse ridges, a proximal and a distal, appear- 

 ing in lateral view as two tubercles or short spines; P,, P2, and P3 are enlarged and 

 stiffened, decreasing in length from Pi, with 9-20 (usually 10-13) segments; the 

 cirri are XVI-XXXV (usually about XX), 17-32 (usually about 20); the 10 

 arms are 35-70 (usually about 50) mm. long (Aru Islands and northern Australia 

 south to Port Curtis, Queensland, and Cape Jaubert, Western Australia; 0-22 



[?27] meters) Oligometrides (p. 61) 



g2. Cirrus segments dorsally with a single transverse ridge, or transverse row of tuber- 

 cles or spines, or paired spines, at least in the distal portion of the cirri. 

 A'. Cirrus segments dorsally with a low median keel and the distal edge slightly 

 thickened and produced, forming a distal transverse ridge; opposing spine 

 forked; P„ absent throughout; Pi usually absent on the inner arms of each 

 postradial series; Pi, P2, and P3 much elongated, exceedingly slender, with 

 greatly elongated segments, and stiffened; Pi is shorter, less stout, and less 

 stiff than P2, with more numerous and shorter segments; P3 resembles Pj, 

 but is of the same length as Pi; about 40 arms about 50 mm. long (Philippine 



Islands; 106 meters) Epimetra (p. 25) 



W. No median keel on the cirrus segments dorsally; opposing spine a simple spine or 

 tubercle, 

 i'. Pi and Pj, and sometimes also P3, are similar, elongated, stiffened, evenly 

 tapering, and of approximately the same length, composed of segments 

 which beyond the first two are much elongated. 

 i'. Pa much shorter, smaller, and weaker than Pj and P2, which are similar and 

 of the same length; cirri with 19-31 segments which are sUbequal, about 

 twice as broad as long, sometimes slightly longer terminally; 10-31 arms 

 and 85-120 mm. long (from Flores to Amboina and Darwin, Australia, 

 and southward to Shark Bay, Western Austraha; 0-40 meters). 



Petasometra (p. 105) 

 i'. P3 resembles Pi and P2 and is abruptly different from the succeeding pin- 

 nules. 



