THE SHORE FISHES OF PERU 67 



ferently shaped disk, the anterolateral margin being slightly concave 

 at tip of snout and then straight and oblique only for a short distance 

 opposite anterior half of snout in goodei, and convex elsewhere; and in 

 the differently shaped ventral fin, which has a nearly straight distal 

 margin, with its outer (lateral) part somewhat produced in goodei, 

 4.15 in length anterior to axil of pectoral. 



The sawtoothlike serrations of the caudal spine suggested the 

 name, serrula. 



Range.— The type (U.S.N.M. No. 127795), a male, 187 mm. long, 

 taken with a seine in Lobos de Tierra Bay, Peru, by the Mission, is 

 the only specimen known. 



UROTRYGON CAUDISPINOSUS. new species 



Figure 14 



Disk a little broader than long, rather pointed anteriorly, its antero- 

 lateral margins slightly concave opposite tip of snout, then gently 

 convex to opposite eyes, more strongly convex elsewhere, broadest 

 opposite about third pair of gill slits, its greatest width 1.7, 1.8 in 

 total length; its greatest length 1.8, 1.9; length anterior to axil of 

 pectoral 2.15, 2.13; length anterior to vent 2.2, 2.25; length posterior 

 to vent 1.95, 2.1; tail from axil of ventral to its tip shorter than 

 greatest length of disk by fully diameter of eye, moderately depressed 

 at base, its depth 1.25, 1.35 in its width at axil of ventral, becoming 

 compressed distally, with a moderately narrow fold above and below, 

 forming a rather narrow sharply rounded caudal fin, nowhere wider 

 than longitudinal diameter of eye; caudal spine slender, about as 

 long as snout, its margins on posterior half serrate, except at tip, with 

 a blunt auxiliary spine below at base in the type only; snout slightly 

 exserted, quite pointed at tip, its length anterior to eye 3.35, 3.3 

 in length anterior to axil of pectoral, its preoral length 3.9, 4.1; inter- 

 orbital 8.9, 9.2; internarial space 9.2, 8.0; eye and spiracle about 

 equal, eye (ball) 4.0, 4.7 in snout; mouth transverse, its width 7.0, 

 7.8 in length anterior to axil of pectoral, 2.0, 2.3 in snout; teeth mostly 

 fiat and smooth; disk smooth except for a few tubercles on the snout 

 and a rather prominent spine in nuchal region; median line of tail 

 with six low spines in advance of caudal spine, and a series of very 

 small slender lateral spines beginning about opposite base of caudal 

 spine, and a series of minute tubercles on the dorsal fin fold; ventral 

 fin distally broadly convex, its outer (lateral) part more than twice as 

 long as its inner part, 4.4, 5.0 in length anterior to axil of pectoral. 



Color rather pale grayish, lighter toward margins of disk; most of 

 dorsal surface of disk and tail in the type with scattered dark specks, 

 these scarcely evident in the paratype; plain pale underneath. 



