28 4 



NATURAL HISTORY BULLETIN. 



cially prominent; last tooth very small, indicated only by a 

 feeble emargination. The abdomen covers the sternum at its 

 base. Chelipeds very unequal, everywhere granulated, the 

 granulation of the smaller being coarser than that of the 

 larger. Carpus with two spines at the inner angle. 



This species is closely allied to P. heterochir (Studer) but 

 differs in the more advanced front and orbital angles, in the 

 additional tooth or lobe of the lateral margin, and in the ex- 

 tensive granulation of the carapace and chelipeds. 



Dimensions. — Male, length 7.7, width 9.7 mm. A male 

 from station 62, measures 11 mm. long and 14.2 wide. 



Distribution. — The type specimen was taken by the "Alba- 

 tross " at station 2415, off Georgia, 440 fathoms (U. S. Nat. 

 Mus. No. 19652); also taken by the University Expedition at 

 five stations off the Florida Keys, in from 70 to about 200 

 fathoms. 



Genus Chasmocarcinus now 



[xda/ur/, a gaping; mptivos, crab.) 

 Allied to Scalopidia Stimpson. Carapace thick, broadest 

 posteriorly, tapering anteriorly, without antero-lateral angles, 

 the lateral margins forming a curve continuous with the an- 

 terior margin. Front narrow, bifid. Orbits marginal, oblong; 

 eyes movable. Ptervgostomian region with a horizontal 

 suture as in Scalopidia. Antennula with basal joint very 

 large and hemispherical. Epistome nearly perpendicular, its 

 margin projecting below the maxillipeds. Maxillipeds widely 

 separated throughout their length, being placed longitudinally 

 instead of obliquely as in Scalopidia; merus suboval, the pal- 

 pus articulating at the antero-internal angle. Abdomen 

 much narrower at base than the sternum; third, fourth and 

 fifth segments coalesced in the male. The sexual appendages 

 pass to the coxse through ducts visible between the sternal 

 segments. Abdominal segments distinct in the female. Cheli- 

 peds with merus trigonal, carpus quadrate, manus short and 

 broad, fingers long and slender. Ambulatory legs slender, 

 subcylindrical, the third pair the longest, the second next, the 

 fourth the shortest. Dactylus of last pair recurved. 



