OXYSTOMATOUS AND ALLIED CRABS OF AMERICA m 



CLYTHROCERUS PERPUSILLUS Rathbun 



Figure 28; Plate 33, Figures 3, 4 



Clythrocerus perpusillus Rathbun, Bull. U. S. Fish Comm. for 1900, vol. 20, 

 pt. 2, p. 90, fig. 14, 1901 (type locality, off Vieques, 15 fathoms; type, 

 U.S.N.M. no. 23777); Bull. Lab. Nat. Hist. State Univ. Iowa, vol. 9, p. 66, 

 1921. 



Diagnosis. — Carapace flat, finely granulate, margins pubescent. 

 One lateral tooth and two indentations. 



Description.- — Carapace slightly broader than long, finely and closely 

 granulate; regions slightly marked; surface flat, the front in the same 

 plane; two triangular, blunt frontal teeth, separated by a sinus equal 



a 



Figure 2S.— Clythrocerus perpusillus, female (23777): a, Dorsal view, X14 (approx.); 6, extremity of 



fourth leg. 



to the reverse of either of the teeth ; emargination of orbit a quadri- 

 lateral obliquely placed; preorbital angle flat, inconspicuous; post- 

 orbital angle a little thickened, dentiform; the eye projects beyond 

 line of orbit. A small, sharp spine, just before middle of lateral 

 margin; a notch behind the spine; halfway between the spine and the 

 orbital angle there is a slight indentation; lateral margins in front of 

 spine fringed with a short pubescence, as are also the merus and 

 carpus of the longer legs. Outer maxillipeds long, the merus joints 

 projecting between the rostral teeth and visible in a dorsal view. 

 Cheliped stout and short, about 1.5 times length of carapace; wTist 

 with a prominent antero-external lobe; hand and movable finger 

 with an inner superior crest; fingers bent strongly inward; thumb 

 stouter than movable finger; the}^ meet along their closing edges. 

 The second pair of ambulatories exceeds the first hj about the 

 length of dactylus; both pairs slender and flat. Dactylus of last 

 two pairs strongly curved and about as long as the curved propodus, 

 against the base of which it fits. 



Measurements. — Female type, length of carapace 2.2, width 2.5 mm. 



Range. — Puerto Rico to Barbados. 



