92 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 5 



Ambulatory legs smooth, margins finely pilumnose. Meri of ambula- 

 tory legs slender; merus of leg three almost five times as long as wide; 

 carpus, propodus, and dactylus similarly attenuated. Length of third 

 ambulatory leg over tvi^ice the width of carapace at lateral angles. 

 Second leg next in length; fourth shortest, its dactyl curving strongly 

 outward. 



Color in life: Carapace deep olive buff with large, irregular patches 

 of citrine drab almost covering frontal, cardiac, gastric, and branchial 

 areas. Eye reddish purple. Ambulatory legs lighter than carapace and 

 netted lightly with neutral red. Fingers apricot orange gradually fading 

 to white tips. Ventral side cream buff. (Petersen) 



Distribution : The 28 specimens collected by Allan Hancock Expedi- 

 tions at 8 Velero stations range from Secas Islands, Panama, to La Plata 

 Island, Ecuador, from shore to 50 fathoms. 



Remarks: This species may be separated from C. latipes Rathbun 

 (1898), as shown by examination of the type (U.S.N.M. No. 21592), 

 by its greater anterior width and less converging sides, by the config- 

 uration of the bilobed front and forward curving orbits, by the greatly 

 elongated third ambulatory leg and slender meri of all the ambulatories 

 with almost straight anterior margins, and by the proportionately longer 

 and narrower ischium and merus of the outer maxilliped. In male speci- 

 mens of any size the asymmetrical cheliped with its high palm and de- 

 flexed fingers becomes the most conspicuous distinguishing feature, the 

 chelae of C. latipes males, of whatever age, remaining equal and similar. 



The same differences will serve to distinguish the proposed new 

 species from C. ferrugineus Glassell (1936), the type of which, in the 

 laboratories of the Institute for Tropical Research of the New York 

 Zoological Society, was examined through the courtesy of Dr. William 

 Beebe and found to be identical with Miss Rathbun's species. The ruddy 

 color of the Zaca specimen is due to a ferruginous mud in which C. 

 latipes frequently occurs and may be removed with a stiff brush. The 

 difference in orbital configuration is negligible. 



The Atlantic Chasinocarcinus most nearly analogous to the proposed 

 new species appears to be C. cylindricus Rathbun (1901). As shown by 

 an examination of the type (U.S.N.M. No. 23765) from Puerto Rico, 

 it has the broad front, the slender meri, and the spinulous fingers of 

 longipes, but the joints of the third ambulatory leg are relatively short, 

 and the merus of the maxilliped is even rounder than in latipes. 



