Clark — New Genera of Unstalked Crinoids. 131 



Geographic distribution. — Tonga Islands and northern Australia to 

 Japan and the Hawaiian Islands. 



Depth. — Mainly littoral, but extending downward to 150 fathoms. 



The short and weak cirri with comparatively lew joints, and the small 

 iirst pinnule are sufficient to differentiate this genus at once. The in- 

 eluded species are, 



/. adrestine (A. H. Clark). I. minuta (A. II. Clark). 



J. briseis (A. H. Clark). I. nana (Hartlaub). 



7". crispa A. H. Clark. I. parricirra (P. H. Carpenter). 



/. psyche (A. H. Clark). 



Compsometra gen. now 



Genotype. — Antedonloveni Bell, 1882 (= Antedon pumila Bell, 1884). 



Similar to Iridometra, but the first pinnule is much longer than, usually 

 about twice as long as, the second and following, and the joints of the 

 proximal pinnules all overlap strongly. 



Color (inspirits). — Olive gray or brownish, sometimes banded narrowly 

 with darker. 



Geographic distribution. — Port Jackson, New South Wales, northward 

 to Tokyo Bay, Japan. 



Depth. — Littoral, and down to 12 fathoms. 



The extraordinary projection of the distal edges of the pinnule joints 

 and the small cirri with comparatively few joints, which are distally much 

 compressed and comparatively broad, distinguish this species at once. The 

 two species at present know are, 



('. loveni (Bell). <?. serrata (A. II. Clark). 



Trichometra gen. nov. 



Genotype. — Antedqn aspera A. II. Clark, 1908. 



Radial faces low, wedge-shaped, or almost triangular, the muscular 

 fossa- practically equilateral right-angle triangles, the distal apices sepa- 

 rated by a small, narrow, and acute notch ; ridges separating the muscu- 

 lar and interarticular ligament fossa' horizontal. Centro-dorsal sub- 

 conical, with somewhat strongly convex sides, thickly covered with 

 small cirrus sockets, somewhat crowded, roughly arranged in two or 

 three columns in each radial area. Forty to sixty cirri with twenty-five 

 to thirty-five joints, elongate in the proximal half of the cirrus, squarish 

 in the distal, the joints in the latter having a sharply carinate dorsal sur- 

 face which projects more or less distally, giving a slightly spinous appear- 

 ance ; the opposing spine is prominent, terminally situated, arising from 

 the entire dorsal surface of the joint, but does not reach the diameter of 

 the joint in length ; the terminal claw is rather longer than the penulti- 

 mate joint, moderately stout, hut comparatively slightly curved. " Small 

 mature " cirri occur about the dorsal pole, which are sometimes less than 

 half the length of the other cirri, consisting of ten or twelve very slender 

 and much elongated joints, with greatly expanded articulations. Distal 

 edges of radials even with the edge of the centro-dorsal, not extending up 

 into the angles of the centro-dorsal ; first costals very short, sometimes 



