16 Clark — A Revhlon of Thalassovietridas and Himerometridas. 



Dii^k iscantily to moderately i)lated; aiiihulaera well i)late(l. 



Radials concealed; i Brj .short, three or more times as hroaif as long; 

 I Br.^ low-triangnlar or widely rhombic, tw^ice as broad as long in the med- 

 ian line; u Br 2, hnt the fnll series rarely develope<l. 



Arms 10 to 20; tirst l)rachial short, slightly wedge-shaped; second 

 larger, irregnlarly qnadrate, nnich broader than long ; following brachials 

 to the tenth or twelfth oblong or slightly wedge-shaped, over twice as 

 broad as long, then becoming triangular or very obliquely wedge-shaped 

 nnich ])roader than long, gradually increasing in length, tiiough remain- 

 ing very oblique distally. The i P>r, ii Br, and proximal part of the arms 

 are very deep, evenly rounded dorsally, compressed laterally; Imt the 

 division series and arms Are not in lateral apposition; the depth of the 

 brachials gratlually decreases distally. The dorsal surface of the arms 

 may be quite smooth, or there may be a faint trace of carination basally, 

 gradually increasing distally, so that tiie terminal portiim of the arms is 

 strongly compressed and .strongly carinate, the brachials with forward- 

 projecting overlapping spines. 



P, the longest, but not especially .stout, .-scarcely larger than V.,, though 

 somewhat more carinate basally; following ])innules decreasing gradually 

 in length to P4 or P,;, which is about two-thirds the length of P,, with 

 nine to twelve joints which are rather broad; distal pinnules slightly 

 longer than P, . 



Colnr. — Bright lemon yellow to cadmium orange, the dull portion of 

 the cirri green, the polished ligiit yellow; sometimes the aims may be 

 grayish, yellow distally. 



Distribution. — Ki and Philipiiine Islands, northward to southern .Jajian 

 and eastward to tiie Hawaiian Islands. 



lJ('l)th.—S2 to at least 102 fathoms. 



The sijccies included in this genus are: 



Para met ra compressa (P. H. Carpenter) 

 fisheri (A. H. Clark) 

 orimi (A. IT. Clark). 



17. Cosmiometra gen. nov. 

 Genotype. — llinla.'^.'^oiiielra kohiaclii A. 11. Clark, illOS. 



Centro-dorsal moderate oi- suiull, the cirrus sockets arranged in two 

 rows, and in tw<i or three more or less regular columns in each radial area, 

 closely crowded or more or lo^ss .separated. 



Cirri \viii-\'xv, 35-00, long, moderately stout, with a well marked tran- 

 sition joint from the seventh to the sixteinith, proximal to which the joints 

 are 'smooth, rounded in ci-oss-section, with a dull surface, distal to which 

 they are highly ]iolished, llattenec], and furnished with i)roniinent dorsal 

 spines; ])roximal cirrus j<iints (except the hasal) nnich longer than broad, 

 distal joints very short. The longer cini are about one-thinl of the arm 

 length. 



Disk scantily or moderately jilated, well plated along the ambulacra ; 

 brachial ami pinnule ambulacra well plated. 



