92 BULLETIN 166, UNITED STATES NATIONAL MUSEUM 



Chelipeds nearly equal, smooth, naked, unarmed, and much less 

 than twice the length of carapace; merus about one-third the entire 

 length, slender and somewhat 3 -sided, but wdthout angles; carpus 

 short and rounded above; propodus nearly one-third as broad as 

 long, basal portion somewhat swollen and about as long as the digits, 

 which are compressed, longitudinally grooved, prehensile edges 

 undulate. First and second ambulatories nearly alike, second the 

 longer, about twice the length of chelipeds, slender, smooth and 

 nearly naked. Dactyli much longer than propodi, compressed, 

 regularly curved, of nearly uniform breadth to the short, acute tip 

 and longitudinally grooved. Third and fourth pairs of legs very 

 slender, pubescent. 



The abdomen is broadest at base of third normal segment which 

 has a smooth rounded tubercle on either side; third to fifth segments 

 fused; penult segment about one-half broader than long, terminal 

 segment nearly as long as the preceding, broader than long, rounded 

 at tip. Appendage of first segment stout and pubescent near ex- 

 tremity, which is obliquely truncate; it sheathes the appendage of 

 second segment which is much longer, the exposed terminal portion 

 being thin, linear, and acuminate. 



Female. Compared to male, carapace broader, thicker, much 

 more convex; front narrower and armed with much smaller teeth; 

 chelipeds smaller, chelae more slender. 



Color. — Carapace bluish with a slight violet tint. Feet and 

 abdomen yellowish white; fingers and ambulatory dactyls rose 

 color. (Milne Edwards and Bouvier.) 



Measurements. — Male (7119), length to tip of submedian spine 15, 

 width 13.2 mm. 



Range. — Off southern New England to Gulf of Mexico; Brazil; 

 eastern Atlantic Ocean; 671 to 2,220 fathoms. 



Material examined. — See table 28, p. 95. 



ETHUSINA SMITHIANA Faxon 



Figure 22; Plate 26, Figure 2; Plate 27, Figure 2 



Aethusina smithiana Faxon, Bull. Mus. Comp. Zool., vol. 24, p. 160, 1893 

 (type locality, off Panama, 134 and 899 fathoms; types, U.S.N.M. no. 20631 

 and M. C. Z. no. 4503); Mem. Mus. Comp. Zool., vol. 18, p. 37, pi. 6, figs. 

 2, 2a, 1895. 



Diagnosis. — Outer orbital spine directed forward, overreaching the 

 eye. Dactyls of first and second ambulatories subequal. 



Description. — Carapace longer than broad, not much narrowed 

 anteriorly. Front 4-toothed, middle pair of teeth large, triangular, 

 separated from one another by a wide triangular sinus which is 

 broader than the antennular sinus; between these teeth the margin 

 is bent down till it meets the epistome below; lateral teeth of front 



