206 BULLETIN 97, UNITED STATES NATIONAL MUSEUM. 



front deep and narrow behind, lateral 

 orbital hood without tooth at outer angle, 

 sinuses shallow, broadly -shaped. Pro- 

 Teeth of supraorbital margin triangular, 

 blunt, outer sinus somewhat shallower 

 than the others. Outer orbital tooth very 

 narrow, straight or a little convex, blunt, 

 pointing straight forward. Antero-lateral 

 teeth two, distant, thick, blunt, posterior 

 margin convex, anterior straight or a little 

 concave. Posterior margin with six or 

 eight tubercles, of which four are large 

 and prominent. Outer lobe of suborbital 

 margin very convex, inner lobe very ob- 

 lique, slightly convex, inner angle an acute 

 tooth; this lobe is a little more than half 

 concealed in ventral view by the large 

 blunt-pointed pterygostomian tooth, which 

 is slightly deflexed and is much more 

 advanced than the lower margin of the 

 orbit. 



Chelipeds of male weak, the left manua 

 two-thirds as high as the right, dactylus 

 as long as upper margin of palm. 



Merus of ambulatory legs narrow, an- 

 gular, with three anterior carinae, upper 

 surface scantily granulous, distal spine 

 narrow, sharp, produced bej 7 ond the seg- 

 ment; anterior lobes of carpus feebly de- 

 veloped ; propodus and dactylus of second 

 and third legs wide, posterior margin of 

 dactylus sinuous. 



A transverse ridge on each of segments 

 1-6 of the male abdomen, that on sixth 

 segment arched forward. 



Measurements. Male (17894), greatest 

 length of carapace (approx.) 12.5, width 

 of same 15.1, length of second leg 27 

 mm.; female, thin shell (Blake] , greatest 

 length of carapace 17.8, width of same 

 20.6 mm. 



Range. Gulf of Mexico, 13 to 88 

 fathoms. 



Material examined. See table. 



