NOTROPIS 151 



§ to ventrals; ventrals falling distinctly short of vent. Scales 5, 34-37, 

 3 or 4; rows before dorsal 13 to IS; scales rather large, thin, and round; 

 lateral line little decurved. 



This is a small and insignificant species, without marked specific 

 characters, obviously limited by preference to the larger rivers 

 (coefficient, 1 .63) and apparently avoiding the lower Illinoisan glacia- 

 tion. It occurs also in considerable numbers in the smaller rivers 

 (1.12), but is usually scarce in creeks and only moderately abundant 

 in the lowland lakes. In Illinois it has occurred in 5 1 collections, 

 rather sparingly distributed along the main streams and in their 

 neighborhood, from the northern boundary to Cairo and from the 

 Wabash and Ohio to the Mississippi. It is reported from the 

 northern Mississippi Valley at large, and from the Ohio basin, 

 ranging from Kansas and western Pennsylvania to Wyoming and 

 Winnipeg. In Pennsylvania it occurs only in the Ohio basin. 



The species is too small to be of any importance except as food 

 for larger fishes. 



Its breeding season is apparently late, no females with swollen 

 ovaries occurring in our collections until the last of June, and speci- 

 mens loaded with eggs being found by us as late as August 27 . The 

 sexual differences are not noticeable. 



NOTROPIS ATHERINOIDES Rafinesque 

 (shiner) 



Rafinesque, 1818, Am. Month. Mag., 204. 



G., VII, 254 (Leuciscus rubellus), 255 (L. copii) ; J. & G., 202 (Minnilus rubellus 

 and M. dinemus) ; M. V., 61; J. & E., I, 293; Ni, 47 (Minnulus dilectus and 

 amabilis), 48 (M. rubellus and M. dinemus); J., 60; F. F., I. 6, 86 (Minnilus); 

 F., 76 (dinemus, part); L., 18 (also arge and dilectus). 



A common slender silvery minnow of the larger rivers, known 

 especially by its bright silvery color and by the posterior insertion of the 

 dorsal fin. Length 2\ to 4J inches; general form- slender, moderately com- 

 pressed, both back and belly about equally and very little arched, the 

 body deepest in front of dorsal fin; profile from dorsal to muzzle a gentle 

 convex curve; depth in length in typical specimens 4.9 to 5.5*. Color 

 translucent green above (olivaceous) ; sides bright silvery, the iridescent 

 emerald, lavender, and cerulean, common in other silvery minnows, being 

 scarcely noticeable in this species; scales above faintly specked, but not 

 blotched or prominently dark-edged; a narrow and rather faint dark 

 vertebral line, and a faint plumbeous lateral band from opercle to caudal; 



♦Specimens in 'some collections from Illinois have the depth as low as 4 to 

 4.25 in length, these shorter and deeper forms seeming to grade insensibly into the 

 typical slender atheriiwides. 



