17 FISHES OF SINALOA. 389 
margin of pectorals and on middle of back, leaving smooth 
areas near middle of pectorals and over branchial arches; 
16 to 20 large spinules along median line of back and 
tail. 
Color, plain brown; caudal fin darker, edged with 
white. 
This species differs from Urolophus astertas, in having 
a wider disk, more acute snout, much smaller prickles,, 
and fewer spinules on back and tail. 
Three specimens obtained in the Astillero, the longest 
Eommches: im entire length — Dype, No. 1700, Ll. S~ |r. 
U. Museum. 
This species is named for Dr. George Warren Rogers, 
a scholarly physician, native of Vermont, but long resi- 
dent in Mazatlan. 
16. Urolophus umbrifer Jordan & Starks n. sp. 
Occasionally taken with Urolophus asterias, but much 
less common. 
Disk round, not wider than long, its length greater 
than tail; snout pointed, not exserted. Snout from eye, 
4% in disk; eyes equal to spiracles; mouth 2 in distance 
to tip of snout; caudal spine inserted in front of middle 
of tail; skin perfectly smooth. 
Color, brown above, with blackish cross-shades or bars, 
radiating from the shoulder; a dark band behind eyes, 
and one from eyes; caudal fin dark. 
One adult female specimen, the uterus containing four 
young. 
This is probably not identical with Garman’s Urolophus 
nebulosus, being perfectly smooth and different in color. 
17. Dasyatis longus Garman. 
Rather common at Mazatlan, where specimens were 
also taken by Dr. Gilbert; also recorded by Mr. Garman 
