OXYSTOMATOUS AND ALLIED CRABS OF AMERICA §9 



and black in color. Chelipeds equal, small, slender; chela smooth, 

 not more robust than carpus; fingers longer than palm, laterally 

 compressed, curved inward, longitudinally grooved, their prehensile 

 edges straight and regularly denticulated. The two ambulatories are 

 very long, the second considerably longer than the first, naked and 

 granulated; propodus a little shorter than merus, slightly com- 

 pressed, with a longitudinal groove on each side; dactylus one half 

 longer than propodus, vertically compressed, slightly curved, longi- 

 tudinally grooved and ribbed, upper edge very sharp. Last two 

 limbs of about equal length, not reaching beyond the distal end of 

 the merus of the second ambulatory, pubescent, except the nail at 

 tip of dactylus; propodus much shorter than merus and not much 

 longer than carpus; dactyli very short and strongly curved. Sternum 

 rather coarsely granulate. 



Color. — Conspicuous red transverse bands on chehpeds and first 

 two pairs of ambulatories; two bands on merus, one on carpus, one 

 on propodus, and one on dactylus. 



Measurements: — Male, cotype (M. C. Z. no. 4498), length of 

 carapace 26.5, breadth 29.5 mm. 



Range. — Bay of Panama, 127 to 259 fathoms. 



Material examined. — See table 27, p. 90. 



Genus ETHUSINA Smith 



Ethusina Smith, Rept. U. S. Comm. Fish and Fisheries for 1882, p. 349 (5), 18»4 

 (type, E. abyssicola Smith). 



Nearly allied to Ethusa, from which it differs in the form of the 

 front and the structure of the eyes. The front between the eyes is 

 quadridentate as in Ethusa, but the basal segments of the antennules 

 are very large and swollen, and occupy the whole width of the front 

 and crowd back the e3"es and antennae into an almost transverse 

 position nearly beneath the outer orbital angles, which are reduced 

 to small lateral teeth far back from the front. Eyestalks very small 

 and immovably embedded in the orbits, which closely surround 

 them to near the tips, except for a narrow space beneath. Only six 

 branchiae on each side. 



Atlantic, Pacific, and Indian Oceans. Deep water. 



KEY TO THE AMERICAN SPECIES OF THE GENUS ETHUSINA 



A'. Front with four teeth or spines. 



B'. Outer orbital tooth directed outward, not overreaching eye. 



abyssicola (p. 91) 

 B^. Outer orbital spine directed forward and overreaching eye. 

 C'. Outer orbital spine longitudinal, not reaching the line of 



the frontal sinuses smithiana (p. 92) 



C. Outer orbital spine oblique, reaching beyond the line of 



the frontal minuses gracilipes (p. 94) 



A^. Front sinuate at middle and with a short outer spine. Cara- 

 pace twice as wide as fronto-orbital distance faxonii (p. 93) 



