Notes on Fishes of Mexico. 3 



Awaous nelsoni Evermann. 



Head 3| ; depth 6 ; eye 5| in head ; snout 3 ; maxillary 2|. D. VI-11 ; 

 A. 11 ; scales about 63. Body long, compressed, and tapering posteriorly ; 

 head large, quadrate ; mouth large, nearly horizontal, lower jaw in 

 cluded ; snout abruptly decurved ; top of head flat, the interorbital with 

 a slight median groove with a thin, raised edge on each side ; maxillary 

 reaching about to vertical of anterior edge of pupil. Teeth in bands 

 on jaws, very small, the outer somewhat enlarged. Pectoral rays normal, 

 the longest 1J in head ; ventrals completely united, the disk free from 

 belly, If in head. Dorsal fins separated by a space about f diameter of 

 eye ; dorsal spines slender, weak, about If in head ; soft dorsal and anal 

 similar, each free from caudal ; caudal fin rather short and rounded, its 

 middle rays about Ij- in head. Inner edge of shoulder girdle with 3 der 

 mal papillae ; gill-membranes broadly united to the isthmus ; eye mod 

 erate, high up, the interorbital width equal to the eye's diameter. Scales 

 ctenoid, very small, and irregularly crowded anteriorly, much larger 

 posteriorly, about 15 rows counting from origin of soft dorsal downward 

 and backward to the anal fin ; head naked, but with slight indication 

 of a few minute embedded scales on opercles. Color grayish ; head 

 mottled and blotched w r ith dark ; side with 7 or 8 black blotches, the 

 largest under middle of pectoral fin ; dorsals pale, crossed by several lines 

 of black spots ; caudal pale, with about 6 or 7 dark cross-bars ; ventrals 

 and anal pale ; pectorals pale, dusted with dark specks and with a small 

 dark blotch at base of upper rays. Length, 4 inches. 



The 7 specimens taken as cotypes do not show any considerable varia 

 tions from the type. The more important variations are indicated in the 

 following description : Head 3f to 3f ; depth 5 to 6 ; eye 5 to 6 in head ; 

 snout 2| to 3. D. VI-11 ; A. 10 or 11 ; scales 60 to 70. 



The number of scales seems to be the most unstable character, but this 

 is partly due to the difficulty of counting them accurately. They are so 

 crowded and irregularly arranged anteriorly as to make definite counting 

 impossible. 



Awaous nelsoni seems most closely related to A. taiasica (Lichtenstein), 

 from which it differs in the larger scales on posterior part of body, the 

 broader interorbital, the longer snout, and the darker coloration. 



I take pleasure in naming this interesting species for Mr. Edward Wil 

 liam Nelson, the well-known ornithologist, in recognition of his early 

 work upon the fishes of Illinois, in 1874-'5. 



