COTTOGASTER 291 



than | of its greatest depth; caudal peduncle short and stout, its depth 

 2 . 1 to 2 . 6 in its length. Color (in preservative) straw to brownish olive, 

 densely blotched and marbled with darker; sides with 8 to IS dark 

 blotches, which are some times obscure, and often extended below lateral 

 line as bar-like bands on anterior portion of body; a faint dark band 

 through nostril to end of snout and a distinct bar below eye; second 

 dorsal and caudal faintly barred in the rays. In breeding males the 

 barring of second dorsal replaced by a more or less uniform dusting of 

 "both rays and membranes of lower half of fin ; first dorsal with a small 

 black spot in front between first two rays and a second and larger one 

 at the back of the fin, usually between 8th and 10th rays. Head 3 . 7 

 to 4 in length, little tapered, muzzle blunt; width of head 1 . 7 to 2 

 in its length; interorbital space flat, 5.5 to 6.4 in head, about § of 

 eye; eye 3.2 to 3.5; nose 2 . 9 to 3.7; mouth moderate, maxillary to 

 front of orbit, cleft 2.9 to 3.2 in head ; premaxillary in Illinois speci- 

 mens as a rule connected by a narrow frenum with the skin of the fore- 

 head; lower jaw slightly shorter than upper; gill-membranes free from 

 isthmus and scarcely connected, distances from muzzle to angle and to 

 back of orbit about equal. Dorsal fin IX, or XI, 13-15; spinous and 

 soft portions as a rule very little separated at base ; height of first dorsal 

 1 . 7 to 2 . 2 in head, second 1 . 6 to 1 . 7 (height of first 76 to 92 per cent. 

 :of second) ; caudal noticeably emarginate; anal II, 10-12, (usually 10 

 or 11); pectorals .9 to 1.3 in head; separation of ventrals as a rule 

 nearly equal to their width at base. Scales 6 or 7, 50-56, 7-9; lateral 

 line complete; cheeks, opercles, and nape scaled; breast naked; bellv 

 usually naked, sometimes scaled for a short distance in front of vent. 



A species of medium size and relatively obscure coloration, 

 notable especially for its extraordinary local distribution, occurring, 

 as it does, almost wholly along the course of our larger streams. It 

 is not common in this state, having been taken but sixteen times 

 from nine localities, six on the Illinois, one oh the Wabash, and two 

 on the Kaskaskia. Twice it was taken from the deep water of the 

 river channel at Havana. 



It occurs also in the Great Lakes, and nas been reported from 

 Erie and Michigan, and elsewhere from the Ohio, the Red, and the 

 Arkansas rivers of the lower Mississippi Valley. Osburn says that it 

 is found in Ohio on sandy bottoms in rivers, but not in small 

 streams. 



Females with eggs were taken from the Illinois River on the 

 18th and the 20th of March, 1899. 



Genus DIPLESION Rafinesque 



Body rather elongate, little compressed; mouth small, inferior, hori- 

 zontal; premaxillaries protractile downward, the groove not visible from 

 above or in front as in other darters, but only .from underneath; known 



