58 



BULLETIN 189, UNITED STATES NATIONAL MUSEUM 



extremity of ventral, increasing in width posteriorly; snout moderately 

 long, 3.8 in length anterior to axil of pectoral, and 5.55 in width of 

 disk; its preoral length only a little less than its length to eye, 4.1 

 in length anterior to axil of pectoral, and 6.0 in width of disk; eye 

 moderately large, its longitudinal diameter scarcely equal to width 

 of spiracle, 4.9 in snout; interorbital moderately broad, concave, 

 about 2.3 times diameter of eye, 2.05 in snout, and 8.0 in length 

 anterior to vent; internarial space and width of mouth equal, 1.5 in 

 preoral length; mouth bent forward very slightly, 9.15 in width of 

 disk; teeth in 32 transverse rows, with a round crown, slightly raised 

 margin, and posteriorly with a low pointed cusp ; prickles in a moder- 



FiGURE 10. — Psammohatis asper, new species. From the type, 480 mm. long, Pachacamac 

 Island, Peru (U.S.N.M. No. 127786). Insert, ventral view of head. 



ately narrow band on lower surface along anterolateral margins of 

 disk, extending back a little beyond posterior rim of spiracles; no 

 prickles on snout or interorbital ; a few along inner margin of spiracles ; 

 a small patch near margin opposite spiracles; present on back behind 

 nuchal region and continued on dorsal surface of tail; a low star- 

 shaped buckler on orbital ridge in front of eye, and indications of two 

 posterior to eye ; a row of 5 median ones in nuchal region ; and a row 

 of low, strong sharp spines on tail, the last spine being situated be- 

 tween the dorsal fins; a patch of small spines on pectorals near inner 



