20 Clark — A Revision of Thalassometridse and Himerometridas. 



Ends of basal rays visible as small intrrradial tubercles; radials slightly 

 visible, or concealed; i I>r, short, 1)and-like, in lateral contact, and later- 

 ally flattened; i Br., broad, rli(iml)ic, three times as ))road as long, with a 

 low blunt median keel; i Br and Urst four or five brachials laterally flat- 

 tened. 



Arms 10; lower l)rachials oblong, the first two with a blunt median 

 keel, l)ecoming weilge-sbaped, about twice as broad as long, or rather 

 broader, after the fifth, soon becoming very obliciue or triangular, about 

 as long as broad, and rather longer in the distal portion of the arm. The 

 brachials all have rather prominent distal edges. 



P] slender, evenly tajiering, with ten to fifteen short squarish joints; Pj 

 similar, or rather sliorter, with about six joints, of which the tliird and 

 fourth are much expanded ; following junnrdes similar to the last; distally 

 the pinnules are moderately slender, somewhat longer than Pj. 



Color. — I>right yellow. 



Distribution. — Ki Islands, northward to the Korean Straits. 



Depth.— 100 to 140 fathoms. 



Included species : 



Strotometra hepburniana (A. H. Clark) 

 " parvipinna (P. H. Carpenter). 



21. Charitometra A. H. Clark. 



The species belonging to this genus as restricted are : 



Charitometra hasicurva (P. H. Carpenter) 

 " incisa (P. H. Carpenter). 



22. Pachylometra gen. nov. 



Genotype. — Antedon distincta P. II. Carpenter, 1888. 



Centro-dorsal a thick disk or a truncated hemis])here, the cirrus sockets 

 arranged in two closely crowded rows, and in usually fairly ilefinite 

 columns, three columns to each radial area; tlie central column, however, 

 may be wholly or partially absent. 



Cirri xx-l (usually xx-xxx), 18-2."), large and stout, the component 

 joints subequal, though slightly shorter in the distal portion, where the 

 cirrus is slightly com])ressed; the most proximal joints are, of course, 

 short; dorsal spines not developed, but the dorsal edge of the distal joints 

 sometimes more or less carinate, and the dorsal distal ends sometimes 

 slightly i)rominent; opposing si)ine small, tul)ercular, or absent; terminal 

 claw al)out as long as the penultimate joint, stout, moderately curved. 



Disk usually fairly completely ])lated, rarely scantily plat('(l; ambulacra 

 well plated. 



Ends of basal rays usually visi))le as small tubercles in the angles of the 

 calyx; radials concealed, or at most slightly visible in the angles of the 

 calyx over tlie ends of the basal rays ; i Br, very short, band-like or cres- 

 centic, deeply incis(!d by a roimded j)osterior process from the i Brj, 

 which rises usually to more or less of a broad rounded tubercle; i lir.^ 

 rhombic, more than twice as broad as loug, the rounded posterior angle 



