NO. K.Ol. SEVENTEEN NEW SPECIES OF CRIXOIDS— CLARK. ^43 



eighth or ninth; next three or four joints simihir, the length then 

 very slowly decreasing, the joints in the middle of the cirrus being 

 squarish and those in the distal part about twice as broad as long; 

 eighth, ninth, or tenth a transition joint; shortly after the transition 

 joint the median part of the distal dorsal edge l)egins to become 

 prominent; this very slowly increases in height, arising from pro- 

 gressively more and more of the dorsal surface of the joints, whi(;h 

 become progressively more and more carinate, so that in the terminal 

 forty-five or fifty the dorsal surface is produced into a sharp, thin keel, 

 straight in front, convex posteriorly, the outer edge parallel w^ith the 

 median line of the cirrus, in height equal to about one-third the diam- 

 eter of the joints which bear them; opposing spine small and blunt, 

 arising from the entire surface of the penultimate joint, the apex 

 subterminal or central, in height equal to about one-third the diam- 

 eter of the penultimate joint; terminal claw small, about equal in 

 length to the penultimate joint, stout, and moderately curved. The 

 cirri are rounded in the basal third, then becoming strongly com- 

 pressed laterally and, when viewed from the side, somewhat broader. 



Ends of the basal rays visible as dorso-ventrally elongated tuber- 

 cles in the angles of the calyx; a deep and narrow cleft betAveen the 

 radials and the centro-dorsal ; radials very narrow, convex proxi- 

 mally, concave distally, with a small, sharp tubercle in the median 

 part of the proximal border; IBr^ about three times as broad as long, 

 the proximal border convex, the distal concave, in close lateral appo- 

 sition, and extending rather well up into the angles of the calyx; 

 the lateral edges are more or less denticulate, and there is a low, 

 though sharp, serrate median keel; IBr^ (axillary) slightly longer 

 than broad, shield-shaped, the posterior border produced into a 

 rounded projection incising the IBr,, the anterior edges concave, the 

 anterior angle somewdiat produced, the lateral edges rather strongly 

 denticulate; it bears a sharp serrate median keel in the proximal 

 two-thirds; IIBr 4 (S-j-l), strongly convex dorsally, in close appo- 

 sition and sharply flattened like the IBr series, the lateral edges 

 somewhat produced and strongly denticulate; IIBr3+4 centrally con- 

 stricted Avith the lateral angles produced as in the other species. 



Twenty arms, 115 mm. long; first braciiial short, slightly longer 

 exteriorly than interiorly, interiorly united, somewhat incised by the 

 second, which is nearly twice as large and has a rounded posterior 

 projection; these two brachials, like the IBr^ and o, have a slightly 

 marked median carination ; third and fourth brachials (syzygial pair) 

 not quite so long as broad, somewhat constricted centrally; next five 

 or six brachials almost oblong, about twice as broad as long, the 

 surface rather strongly concave, then becoming wedge-shaped and 

 soon triangular, nearly as long as broad, and after the middle of the 

 arm wedge-shaped again and about as long as broad. The arms are 



