56 



BULLETIN 189, UNITED STATES NATIONAL MUSEUM 



convex elsewhere; width of disk 1.33 in total length; its greatest length 

 1.85; length anterior to axil of pectoral 2.05; length anterior to vent 

 2.0; length posterior to vent 2.2; tail depressed throughout, its depth 

 1.65 in its width at axil of ventral, with a cutaneous lateral fold begin- 

 ning shortly before end of inner lobe of ventral, increasing in width 

 posteriorly, extending fully to tip of tail; snout moderately short, 3.8 

 in length anterior to axil of pectoral, and 5.8 in width of disk, its 

 preoral length notably less than its length anterior to eye, 4.5 in length 

 anterior to axil of pectoral, and 6.85 in width of disk; eye moderate, 

 its longitudinal diameter about equal to width of spiracle, 4.25 in 

 snout; interorbital concave, about two times diameter of eye, 2.1 in 



Figure 9. — Psammohatis cavdispina, new species. From the tj'pe, 390 mm. long, Chimbote, 

 Peru (U.S.N.M. No. 77710). Insert, ventral view of head. 



snout; internarial space somewhat narrower than mouth, 1.3 in preoral 

 length, 6.0 in length anterior to vent, mouth bent forward slightly, 

 its width 1.05 in preoral length, 7.2 in width of disk; teeth in 33 

 transverse rows, with a round crown surmounted by a sharp central 

 cusp, apparently lost through wear on some of the front teeth; prickles 

 in a broad band on lov/er surface of disk along anterolateral margin of 

 disk; a similar band on upper surface, except toward tip of snout; 

 scattered minute ones on interorbital region, beginning again in 

 nuchal region and extending backward on the middle of the back 



