98 CONTRIBUTIONS TO NORTH AMERICAN ICHTHYOLOGY — II. 



bh. Pectoral spines extremely strong, more than half the length of head, curved; 

 their posterior serrse strong, spine-like, hooked backward, each about as long 

 as the diameter of the spines: 

 d. Adipose fin connected with the caudal fin ; distance from snont to dorsal 

 about 2| in length ; pectoral spine 2^ in this distance ; dorsal fin higher than 

 long ; body not very elongate nor much depressed ; the dorsal region often, 

 somewhat elevated ; the depth usually 4| to 5 in length ; head 3f to 4 ; 

 dorsal nearer anal than tip of snout ; anal 12 or 13 rays ; pectoral spino 

 curved and sharply serrate without, with six strong recurved pectinations 

 within each as long as the diameter of the spine ; body much mottled, black 

 and grayish ; top of head, tip of dorsal, middle of .adipose fin, and edge of 

 caudal definitely black ; body with four broad cross-blotches, one before 

 dorsal, one behind it, one on middle of adipose fin, and one small one behind 



it ; size small - MiURUS, 26. 



dd. Adipose fin entirely free from caudal fin, separated from it by a space 

 nearly equal to the diameter of the eye ; spines as in miurus but rather weaker ; 

 head 3^ in length i depth 5^ ; distance to dorsal 2f in length ; pectoral spine 

 2^ in distance to dorsal : width of head 4^ in length ; body moderately elon- 

 gated ; head broad and flat, much like that of a Pelodichthys ; anal fin with 

 but eleven rays ; color mottled gray, faintly and irregularly spotted with 



darker .-.. Eletjtherus, 27. 



it. Pectoral spine entire or grooved behind, never retrorse-serrate ; adipose fin con- 

 tinuous, not notched : 



e. Head small and narrow, longer than broad, with small eye ; its length about 4 

 in body, its width 5^; upper jaw much projecting; spines very short and 

 slender, that of the dorsal not one-ffhird the height of the fin, and all less 

 than one-fourth the length of head ; body slender, but not elongate ; dis- 

 tance to dorsal 2f in length; pectoral spine 5 in this distance, slightly 

 retrorse-serrate without, grooved within ; depth 5^ in length ; dorsal nearer 

 anal than snout ; anal 14 ; color mottled, rather pale .. .Leptacantiius, 28. 



ee. Head short, broad, and deep. 



/. Head shorter, narrower, and smaller in every way, than in the next, the body 

 more elongate, more compressed but less deep, the width 4^ in length of 

 body; length of head 4J; depth of body 5^; snout to dorsal one third of 

 length; pectoral spine 2^ in distance to dorsal; jaws nearly equal ; anal 

 rays 15 or 16 ; lower barbels pale ; coloration yellowish brown, with a lateral 

 dark streak and two dorsal ones Gyrinus, 29. 



ff. Head 3| to 4 in length, larger than in any of the other species ; width of head 

 3f in length ; distance from snout to dorsal 2f in length ; body compara- 

 tively short and thick, the depth 4 to 5 in length ; spines stout and rather 

 long, that of the pectoral fin straight, about half the length of head; 2J in 

 distance to dorsal fin ; entirely free from serratures outside, grooved within ; 

 dorsal higher than long, nearer anal than snout ; anal high, of 13 rays ; adi- 

 pose fin high, continuous, without any notch at all ; caudal fin arising very 

 near anal; barbels short; the lower dark; color nearly uniform yellowish 

 brown, never blotched ; a narrow black lateral streak, which is usually con- 

 spicuous SlALIS, 30. 



