Boone, Crustacea, Cruise of "Alva," 1931 71 



large crabs, where the postlateral and posterior margins join. The 

 sidewalls of the carapace, near to the proximal joints of the legs, are 

 covered with coarse setae. The epistome is wide, not sunken. The 

 buccal cavern is squarish, wider than long, the efferent branchial chan- 

 nels are deep but are not emphasized by ridges. The external maxil- 

 lipeds are close-fitting, the ischium with an oblique, longitudinal sul- 

 cus on the outer face and with its inner lateral margin bearing a dense 

 brush of setae. The merus is oblique, but does not have its antero- 

 external angle produced laterally. The sternal plastron is widely 

 oval, smooth, with a few short setae along its lateral edges. The male 

 belt is a wide, blunt tipped triangle, composed of five segments; the 

 first of which is very short, hinge-like, nearly concealed beneath the 

 margin of the carapace; the second segment is clearly defined, about 

 three times as long as the first segment; the third, fourth and fifth 

 segments are fused, with only two faint, transverse lines indicating 

 their fusion; the sixth segment is about as long as wide; the tip is 

 triangulate, blunt. The female belt is widely oval, with setose 

 margins. 



The antennulae are rather slender, when extended do not reach to 

 the base of the cornea; they fold nearly transversely and are sepa- 

 rated by a prominent interantennulary septum. 



The antennae have the basal article short and broad, with its outer 

 distal angle produced into a rounded lobe that extends into the orbit; 

 the flagellum, which is about twice the length of the long diameter of 

 the orbit, is situated in the orbital hiatus. 



The chelipeds are very massive in the large males, being about 1.8 

 times as long as the carapace is wide; the merus three-sided, extend- 

 ing the distal half of its length beyond the carapace ; its anterior lat- 

 eral margin armed with three coarse spines and its posterior lateral 

 margin armed with a distal spine and sometimes a spine further back ; 

 the carpus is rounded on the upper surface and has a strong acumi- 

 nate tooth at the inner angle and two well spaced, short spines on the 

 outer margin ; the palm is massive, the outer surface moderately con- 

 vex, its height equal to about two-thirds its length, neither prismatic 

 nor costate, but with a single sharp spine at the upper proximal bor- 

 der and two, lesser, well spaced, subdistal spines on the upper margin 

 near the base of the finger; there is a similar spine on the inner sur- 

 face of the palm, about midway its height and above the base of the 

 poUex. The fingers are stout, about two-thirds as long as the palm, 

 with a wide gape, meeting only at the pointed tips. The upper finger 



