Boone, Crustacea, Cruises of "Ara" and "Alva" 253 



The eyes are large, shining black, subspherical. 



The inner antennae have the basal articles beneath the eye, 

 shielding its inner inferior side, the distal peduncular article ter- 

 minating about beneath the subdistal pair of rostral spines ; the 

 two-branched flagella extend to the base of the propodus, the 

 outer branch being about one-third thicker than the inner one 

 and slightly longer. 



The outer antennae have a five-jointed peduncle, the first arti- 

 cle being ventral, with a short, acuminate, median distal spine, 

 also with the aperture of the green gland; the second article is 

 the first one dorsally visible and is produced into a strong, out- 

 jutting sharp tooth at the outer distal angle; this supports the 

 short, lanceolate scaphocerite, which extends only as far for- 

 ward as the subdistal pair of rostral spines. The inner and distal 

 margins of the scaphocerite are convex, furnished with long 

 plumose setae, the greatest width of the scaphocerite being mid- 

 way the length of the blade, tapering in both directions ; the outer 

 lateral margin slightly concave, the outer distal angle a sharp 

 tooth; the third, fourth and fifth antennal peduncular articles are 

 successively smaller, located beneath the scaphocerite ; the flagel- 

 lum is multi-articulate, the annuli thickened proximally, tapered 

 distally, this flagellum extending beyond the cheliped from one 

 to one and a half inches. 



The first pair of chelipeds are greatly enlarged, being equal 

 to the total length of the body and subequal to each other; the 

 merus triquetral, very slender proximally but thickened distally 

 with a sharp tooth at the upper distal angle and a very much 

 stronger projecting tooth at the outer angle ; the carpus is three- 

 fifths as long as the merus but much wider and thicker, armed 

 with five longitudinal series of spines, one row each on the inner 

 and outer lower lateral margins and three rows, a median and 

 two submedian rows, on the upper surface, the spines being of 

 irregular size, but coarse, compressed laterally to a ridge and 

 very sharp distally. The propodus and finger together are as 

 long as the carapace plus the first two abdominal somites ; these 

 joints are swung obliquely so that the fingers open nearly hori- 

 zontally, the lower margin of the fixed fingex and palm forms 

 the outer lateral margin, and the upper margin of the palm and 

 hinged finger forms the elevated inner lateral margin. The pro- 

 podus is nearly four-sided in cross-section, due to the fact that 



