ERICYMBA 1S7 



to 5.2 in length; caudal peduncle as a rule about f length of head, 



slender, its depth contained 2.2 to 2.9 in its length. Color pale olive 



above, the scales rather narrowly and indistinctly dark-edged; sides pale 



silven- with bluish reflections; a dark dorsal streak and an indistinct 



plumbeous lateral band developed 



posteriorly; no caudal spot; fins all 



plain; cheeks and opercles bright 



silvery ; iris silvery below, with some 



dusky above; spring males without 



bright colors. Head long for its 



depth, depressed above, with prom- 1 



inently decurved muzzle ; chin broad 



and flat ; length of head 3.5 to 3.7 



in body and head, its width 1 . 9 to 



2.4 in its length; interorbital space p IG 38 



nearly flat and quite narrow, 3.5 to 



3 . 9 in head ; eye 3 . 3 to 3 . 6 in head ; suborbitals, interopercles, and lower 



jaw-boncs.with greatly developed mucus channels, appearing externally as 



vitreous streaks ; nose 2 . 6 to 3 in head, always distinctly longer than eye ; 



mouth small, horizontal, subinferior, tip of upper lip below level of lower 



margin of orbit; maxillary 3.5 to 4 in head, not reaching past anterior 



nostril-opening; lower jaw much shorter than upper; isthmus less than 



pupil. Teeth 4-4, or 1, 4-4, 1, rather strongly hooked, the grinding 



surface somewhat weakly developed as a narrow groove whose edges are 



smooth; intestine .9 to i .0 times length of head and body; peritoneum 



bright silvery, with a very few scattered dark specks. Dorsal fin with 8 



rays, set nearlv directly over vcntrals, but distinctly nearer tip of snout 



than base of caudal; longest dorsal ray 1 . 1 to 1 .2 in head; anal rays 8, 



sometimes 7 ; pectorals long, reaching nearly to ventrals ; ventrals past 



vent but not quite to front of anal. Scales 5, 32-35, 3; 13 to 15 rows 



before dorsal; breast without scales; lateral line nearly straight. 



This interesting little fish is especially peculiar because of the 

 tubular cavities, the so-called mucus canals, in the bones of the side 

 of the head and the lower jaw. It has, on the whole, an easterly 

 distribution, ranging, according to Jordan and Evermann, from 

 Michigan and western Pennsylvania to Kansas and southward 

 to western Florida. In our collections it has been limited almost 

 wholly to the central eastern part of the state, occurring chiefly in 

 the headwaters of the minor tributaries of the Wabash and in the 

 upper course of the Kaskaskia River, and in the tributaries of the 

 Iroquois and of the Sangamon. The distribution map of the state 

 for this species suggests a relation to an eastern center, and an ex- 

 tension past the watersheds from the tributaries of the Wabash to 

 the headwaters of adjacent streams. Our 74 collections came in si i 

 large a proportion from the smaller streams that the coefficient < if 

 frequency for creeks is 4.85, and that for the smaller rivers is 1.06. 



