THE SHORE FISHES OF PERU 95 



very strong, with entire margins; dorsal injured, its origin about an 

 eye's diameter behind origin of anal, and a little nearer base of caudal 

 than posterior margin of eye; caudal fin missing; anal moderately 

 long, its origin about equidistant from anterior margin of eye and 

 base of caudal, its base 2.25 in length; pectoral injured, inserted about 

 an eye's diameter nearer tip of mandible than origin of anal. 



Color in alcohol plain grayish above, sides of head and of chest and 

 abdomen silvery; tip of mandible and of snout, and back with dusky 

 points; occiput with a pair of elongate dark spots. 



The foregoing description is based on a specimen with injured fins, 

 having a length of 66 mm. to the base of the caudal, which must 

 serve as the type (U.S.N.M. No. 127809). It was taken by the 

 Mission in an otter trawl in the Gulf of Guayaquil, off Puerto Pizarro. 

 Two very small specimens, each about 38 mm, long, taken in a dredge 

 in Sechura Bay, apparently also are of this species. Besides the 

 Peruvian material I have examined rather numerous small speci- 

 mens, 27 to 77 mm. (20 to 61 mm, to base of caudal) in length, 

 from Panama Bay, which evidently also are of this species. The 



Figure 19. — Odontognathus tropicus, new species. From the type, 66 mm. long to base of 

 caudal, Puerto Pizarro, Peru (U.S.N.M. No. 127809). 



young are slender and do not have the concavity underneath the 

 pectoral in the ventral outline, which generally becomes evident at 

 a length, without the caudal fin, of about 60 mm,, and of course the 

 maxillary is not produced. The following enumerations and propor- 

 tions are based on six or more specimens from Panama, ranging in 

 length from 52 to 75 mm. (43 to 61 mm, to base of caudal) : D. 14 

 to 16; A. 43 to 47; P. 14 or 15; ventral scutes 26 to 28; gill rakers 8 to 

 10+ 18 to 21 ; vertebrae 46 (one specimen dissected) , Head 4,2 4o 4.5 

 in length; depth 4.2 to 4.6; anal base 2.45 to 2.7. Eye 3.2 to 3.85 in 

 head; snout 4,1 to 4.75; maxillary 1.5 to 1.8; mandible 1,5 to 1.75; 

 caudal peduncle 2,55 to 2,75; pectoral 1,55 to 1,65, 



This species differs from 0. panamensis (Steindachner) , the only 

 other species of the genus known from the Pacific coast of America, 

 in the notably shorter anal; the more anterior position of the dorsal, 

 which has more rays; and in the larger head and longer mandible. 

 In 0. panamensis, of which a single specimen, 125 mm, in total length, 



