30 



BULLETIN 97, UNITED STATES NATIONAL MUSEUM. 



ubdomen of male not covering the space between the coxae of the 

 last pair of legs. Third to fifth segments fused. 



The type-species is said to have come from China. The other 

 species are American and are analogous species on opposite sides of 

 the continent: atlantica (Atlantic); ciliata (Pacific). 



KEY TO THE AMEUICAN SPECIES OF THE GENUS PRIOXOPLAX. 



A 1 . Carapace with three lateral teeth atlantica, p. 30. 



A*. Carapace with four lateral teeth ciliata, p. 31. 



PRIONOPLAX ATLANTICA Kendall. 



Plate 6, figs. 1 and 2. 



Prionoplax atlanticus KENDALL, Bull. U. S. Fish Comm., vol. 9, for 1889 

 (1S91), p. 305 (type-locality, Int. 25 23' 00" N. ; long. 82 43' 00" W., 

 23 fathoms; holotype male, Cat. No. 15272, U.S.N.M.). 



Diagnosis. Nearly naked. Three side teeth. Front, seen in front 

 view, not projecting below the lower margin of the orbit. Spine at 

 outer angle of wrist. 



Description. Carapace smooth and shining, very finely granulate 

 along the sides, regions scarcely indicated; almost flat from side to 



side, convex fore and 

 aft; sides strongly con- 

 verging. 



Front ofie - third of 

 width of carapace, an- 

 terior margin bilobed, 

 lobes convex, side mar- 

 gins slightly concave. 

 Orbits sloping obliquely 

 backward, upper mar- 

 gin slightly sinuous, 

 lower margin deeply 

 hollowed out below the 

 cornea, a notch in the 

 hollow. Eyestalks increasing in size distally, corneae very large 

 with a ventral aspect. 



Antero-lateral margins armed with three sharp teeth, the first one 

 forming the angle of the orbit, the second the largest and nearer 

 the first than it is to the third. 

 Posterior border of the epistome very prominent. 

 Buccal cavity much wider in front than behind, maxillipeds with 

 a rhomboidal gape. Merus joints granulate, ischial joints sparingly 

 punctate. 



a b 



FIG. 8. PRIOXOPLAX ATLANTICA, MALE HOLOTYPE. 

 a, ABDOMEN AND PART OP STERNUM, X 8 ; 6, OUTER 



MAXII.LIPED, DOTTED LINE MAIiKINQ MEDIAN AXIS, 



X 12. 



