474 BULLETIN 18 9, UNITED STATES NATIONAL MUSEUM 

 Genus SYMPHURUS Rafinesque, 1810 



Body rather elongate, more or less lanceolate, the depth being con- 

 tained more than three times in the length; mouth rather small; 

 teeth small, in a band in each jaw on blind side; gill opening rather 

 small, the membranes united below, free from the isthmus, but adnate 

 to shoulder girdle above; lateral line wanting; scales ctenoid; pec- 

 toral fins wanting in adults; one ventral fin present, well separated 

 from the anal, median in position. 



Thi-ee species are recorded herein from Peru, two of them being 

 new to science. In identifying the Peruvian material, it has seemed 

 necessary to examine virtually all the specimens of the genus from the 

 Pacific coast of America included in the collection of the U. S. National 

 Museum. The material examined included specimens of all the 

 species known from the Pacific coast of America, exclusive of fasciolaris 

 Gilbert and melanurus Clark. A key to all the species is included, 

 which is intended to show especially wherein the new species described 

 differ from the others. Furthermore, nearly all the species may be 

 expected in Peru. 



Because of the soft margins of the snout and opercle and the in- 

 definite outline of the orbits, the measurements of the snout, eye, and 

 maxillary are rather indefinite and accordingly are not used in the key. 

 In enumerating scales the oblique series running upward and back- 

 ward, between the upper anterior angle of opercle and base of caudal, 

 were counted. 



KEY TO THE SPECIES 



a. Mouth rather large, the maxiUary reaching nearly or quite to, or even 

 beyond, posterior margin of lower eye; body usually rather elongate, the 

 depth being contained about 3.4 to 4.5 in length. 

 h. Body very elongate, the depth 4.3 to 4.5 in length; mouth large, the maxil- 

 lary reaching beyond posterior margin of eye; teeth minute, missing 

 on posterior fourth or so of both jaws on ocular side; dorsal with 100 to 

 105 rays; anal with 83 to 86; scales 87 to 92; body uniform brown 

 (very young with dark cross bars) ; caudal, and dorsal and anal pos- 

 teriorly, uniform dusky elongatus 



66. Body generally deeper, the depth about 3.6 to 4.1 in length; mouth smaller, 

 the maxillary reaching nearly or quite to posterior margin of eye; dorsal 

 with 88 to 98 rays; anal with 73 to 81. 

 c. Body moderately elongate, the depth 3.9 to 4.1 in length; snout not pro- 

 jecting beyond mouth; teeth minute, missing on posterior fourth or so 

 of both jaws on ocular side; dorsal with 88 to 93 rays; anal with 70 to 

 74; scales 82 to 87; body brownish, with somewhat indefinite cross 

 bars; caudal and posterior parts of dorsal and anal uniformly black. 



leei 

 cc. Body deeper, the depth 3.4 to 3.7 in length; snout distinctly projecting 

 in advance of mouth; teeth in jaws very weak, missing on posterior 

 three-fourths or so of both jaws on ocular side; dorsal with 94 to 98 

 rays; anal with 77 to 81; scales 84 to 89; body plain brownish; 

 caudal and posterior or so of dorsal and anal uniform dusky. 



sechurae, new species (p. 475) 



