39° 



CALIFORNIA ACADEMY OF SCIENCES. l8 



from Acapulco and from Panama, and by Evermann & 

 Jenkins from Guaymas. 



18. Pteroplatea crebripunctata Peters. Mantaraia. 

 Very common on sandy shores everywhere about Ma- 



.zatlan, from which locality it was originally described; 

 also taken by Dr. Gilbert. 



Width of disk twice length to posterior end of anal slit; 

 snout forming a regular curve from a little in front of 

 middle of pectorals, a very small blunt projection at tip; 

 anterior margin of disk convex near snout and lateral 

 angles, pectorals concave medially ; posterior margin 

 weakly convex; posterior angle broadly rounded; lateral 

 angle sharply rounded ; distance from snout to a line drawn 

 through lateral angles, 2^ times in distance to tip of tail. 



Interorbital a little wider than its distance to tip of snout ; 

 eyes twice spiracles; mouth equals snout, 6 1 /, in disk. 

 Tail rat-like, with a scarcely perceptible fold of skin on 

 its dorsal side. 



Ground color olive brown, everywhere with small dark 

 points, not so close set as in Pteroplatea rava, indis- 

 tinct greyish spots, half as large as iris, scattered over 

 the body among the dark points, these spots are more dis- 

 tinct on anterior edge of disk; tail mottled with darker; 

 lower parts light. Markings nowhere so distinct as in 

 the next species. 



Several specimens, the largest 15 inches long. 



19. Pteroplatea rava Jordan & Starks, n. sp. Man- 

 taraia COLORADA. 



One specimen taken in the Astillero at Mazatlan. 



Length of disk 1 2 A> width ; snout forming an angle 

 which is almost a right angle; pectorals slightly concave 

 medially ; posterior margin of disk weakly convex ; pos- 

 terior angle not broadly rounded, but curved in some- 

 what suddenly; lateral angles acute. 



