14 Clark — A Revision of Thalassometridse and Himerometridss. 



c^ more than 40 cirrus joints; genital i)innules moderately long; 

 twenty or more arms; rays and division series sharply flattened 

 laterally (17) Cosmiometra. 



(12) Stylometra A. II. Clark. 



The species belonging to this genus, in addition to an undescribed form 

 from the Caribbean Sea, is : 



Stylometra spinif era (P. H. Carpenter). 



(K!) Thalassometra A. IT. Clark. 



The species remaining in this geniis as restricted are : 

 Thalassometra agassizii (Hartlaul)) 



aster (A. H. Clark) 

 " ?</.t/>njosa (P. H. Carpenter) 



" echinata (P. H. Carpenter) 



" gigantea (A. H. Clark) 



" haivaiiensis (A. H. Clark) 



" multispina (P. PI. Car])enter) 



" pergracilis (A. H. Clark) 



" puhescens (A. H. Clark) 



r//?o.s« (A. H. Clark). 



14. Stenometra gen. nov. 



Genotype. — Antcdon (juinqnecosfafa V. II. Carpenter, 1888. 



Centro-dorsal small, truncated-conical or more or less columnar, the 

 cirrus sockets arranged in ten definite columns of two or three each, each 

 column sei)arated from its neighbors by more or less developed ridges, 

 those situated interradially being usually more prominent than the others. 



Cirri xx-xxxv, 50-90, long and slender; first few joints very short, 

 then becoming much longer than wide, but becoming short again in the 

 distal half, and very short toward the end of the cirrus; middle and distal 

 joints l)earing prominent dorsal si)iiies. The cirri are from a))out lialf to 

 two-thirds or more of the arm length. 



Disk moderately or well plated; ])lating on the brachial and pinnule 

 amV)ulacra well developed. 



Ends of basal rays visible as dorso-ventrally elongate tubercles in the 

 angles of the calyx ; radials short or concealed in the median line, but 

 alway.s more or less visible in the angles of the calyx; when visible in the 

 median line, with a more or less sharj) meilian keel, and usually more or 

 le.ss strongly denticulate lateral (sonictinics also anterior) edges; i Br, 

 very short, sliarply carinatc; i l">r,, large, rhombic, sharply carinate; ii Hr 

 and III P>r (when jiresent) 2, shar})ly carinatc like the i Hr. 



Arms 10 to 21, strongly compressed and sharply carinatc throughout 

 their whole lengtii, the median distal edge of the brachials being promi- 

 nent, produced into a long overlapping spine in the outer half of the 

 arms. 



