COTTOGASTER 291 



' 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 15 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 specimens as a rule 

 connected by a narrow frenum with the skin of the forehead; 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; 

 belly 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, occur- 

 ring, 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 on 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 has 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, horizontal; 

 premaxillaries protractile downward, the groove not visible from above or in 

 front as in other darters, but only from underneath; known also by the non- 



