42. Body slender; length over five times depth; upper jaw strongly project' 



ing; southeastern U. S. 



Ameiurus platycephalus (Girard) Brown Catfish 

 Depth more than one-fifth of length; jaws various 43. 



43. Anal rays 23 to 27; chin barbels whitish; Great Lakes and southwards 



Ameiurus natalis (LeSueur) Yellow Bullhead 

 Anal rays 17 to 25; chin barbels gray to black 44. 



44. Pectoral spines short, slightly over one-third length of head, almost 



smooth; anal fin with light rays contrasting with dark membranes; 

 jaws almost equal; New England to Neb. and southwards 

 Ameiurus melas (Raf.) Black Cat 

 Pectoral spines longer, almost one-half length of head, serrate in A. 

 nehulosus; fins more uniformly colored; upper jaw projecting in 

 A. nehulosus 45. 



45. Color usually mottled or blotched; upper jaw longer than lower; Maine 



to N. D. and southwards 



Ameiurus nehulosus (LeSueur) Common Bullhead, Horned Pout 

 Color usually plain dark above; jaws almost equal; southeastern U. S. 

 Ameiurus erehennus Jordan Black Cat 



46. With an adipose fin (a small flap of skin without any supporting rays, 



between the dorsal fin and the tail) 47. 



No adipose fin 74. 



47. With three branchiostegals (rays in each gill membrane ventral to the 



operculum) ; no pseudobranchiae (small gills on the under side of the 

 operculum); southern Texas; Family Characinidae (mostly tropical 

 species) 



Astyanax mexicanus (Filippi) Characin 

 With four or more branchiostegals; with pseudobranchiae 48. 



48. Pectoral fins extending well back beyond the insertion of the pelvic fins; 



with two spines in the anterior end of the dorsal fin; Family Per cop' 



sidae Trout-perch 49. 



Pectoral fins not extending back beyond the insertion of the pelvics; no 



spines in the dorsal fin Trout, Salmon, Whitefish and Graylings 50. 



49. Dorsal spines weak; lateral line complete; northeastern and north-central 



states 



Percopsis omiscomaycus (Walbaum) Trout-perch, Sand-roller 

 (Percopsis guttatus Agassiz) 

 With two strong dorsal spines; lateral line more or less incomplete; Pa- 

 cific Slope 



Columhia transmontana E. 6? E. Western Trout-perch 



50. Lower jaw articulating under or before the eyes; with less than one hun- 



dred scales in the lateral line 51. 



Lower jaw articulating behind the eyes; scales very small, more than one 



hundred in the lateral line; Family Salmonidae Trout and Salmon 62. 



51. With nineteen to twenty-two rays in the dorsal fin; upper Missouri val- 



ley; Family Thymallidae Graylings 



Thymallus montanus Milner Grayling 



264 



