37] STUDY OF SOUTHERN WISCONSIN FISHES— CAHN 37 



specimens I believe that Michigan was considered the western limit of its 

 range. 



31. Opsopoeodus emiliae (Hay). Small-mouthed Minnow. 



Rather an uncommon species, taken by me only in the Oconomowoc 

 and Ashippun rivers. Small in size — usually under two inches — the fish 

 often escapes notice, as it frequents water somewhat muddy in quality 

 and of considerable depth. In the Ashippun the species inhabits the 

 deeper holes over soft bottom, where the fish feed upon entomostraca and 

 small Crustacea such as Hyalella. 



32. Notemigonus crysolencas (Mitchill). Golden Shiner. 



A species with a very peculiar distribution within the county. For 

 a long time I knew it only from Washtub lake, where it is extremely 

 abundant. In 1924 I found it in shallow weedy water along the shores of 

 Lac La Belle, and in 1925 I took it from shallow water weeds in Oconomo- 

 woc lake. In Washtub, which is a small lake nearly choked with weeds, 

 the species seems to be at its optimum. The fish reach a length of four 

 inches or less, and are not particularly hardy if used as bait. A great 

 variation in color exists locally. Those from Washtub are very dark with a 

 brassy tinge, while those from La Belle are very light and show almost no 

 trace of yellow. The food consists largely of entomostraca Hyalella, with 

 a large number of young water-boatmen (Corisa sp.) and backswimmers 

 (Notonecta sp.), and occasionally young leeches (Placobdella parasitica). 

 Aquatic vegetation comprises about 20% of the food. Gravid females 

 have been taken early in June and well into July, while spawning apparently 

 occurs normally about the middle of June. 



33. Cliola vigilax (Baird & Girard). Bullhead Minnow. 



Locally common, but very circumscribed in distribution. I have taken 

 the species in the Menomonee River, closely associated with Pitnephales 

 promelas and Hybognathus nuchalis, and in the Ashippun river in associa- 

 tion with Campostotna anomalum and Catastomus commersonii. The food 

 consists of about equal parts of aquatic vegetation, entomostraca and 

 occasionally mollusca, such as small Physa and Planorbis. 



34. Notropis cayuga (Meek). Blunt-nosed Minnow. 



A very abundant species in the Mukwonago river, and present to a 

 much less extent in the Fox and Oconomowoc rivers. I have taken the 

 species several times in Oconomowoc lake, but it is very rare in lakes. 

 Usually found associated with Notropis comutus and N. whipplii, it 

 prefers gravel bottom, medium current and relatively shallow water, 

 seldom being taken in water more than twenty inches deep. The food-is 

 largely entomostraca, though insect larvae and a little vegetable matter 

 in the form of algae are often found in the stomachs. Although I know 

 nothing of the breeding habits, it would seem that the species is a late 

 breeder, as gravid females have been taken commonly in July and several 

 as late as August 10. A good bait minnow. 



