IOWA ACADEMY OF SCIENCES. 45. 



the Cdtosiom'ulac delight in muddy waters and muddy bottom. The Centratrhidae, 

 the Percidae and the Ci/prinodontidne delijj:ht most in clear cold streams. 

 Especially abundant are they if to clearness and coldness be added a bottom 

 studded with boulders and smaller rocks affording' thus means for hidinpr. In 

 such situations especially may the beautiful <jenus Ethcostoma be found, both in 

 great numbers and variety. 



The subjoined list of species collected and studied by the writer in this area is 

 made after the system adopted by Doctors .Jordan and Gilbert, in their masterly 

 "Synopsis of the Fishes of North America"*. 



1' ETUOMYZONTI D.K. 



rrhe Lampreys.) 



Petromyzon coucolor Kirtland. — This form has occurred only in the Des Moine& 

 nver, at Des Moines. Two specimens have been secured, and both of these were 

 taken from large catfish caught in the river within the city limits. Both were 

 captured in March, one in 1887, the other in 1889. It is the habit of this species 

 to ascend the river to spawn but it does so with the aid of other and larger fish. 

 It is fairly common, according to report of fishermen, on large catfish in early 

 spring, though but these two have been secured by us. 



LEPIDOSTEID.E. 



(The Gar«.) 



Lepidosteus osseus Linnaeus. — Des Moines river; Raccoon river, Des Moine.s- 

 and Adel. 



The common or long-nosed gar is not taken except by fishermen and they 

 obtain it rarely. Two forms of this genus are commonly recognized but onl\- 

 one of these has been seen by us within our limits. 



SILURID.E. 



(The Gatfishes.) 



Ictaliirus piinctatiis Rafinesque.— Raccoon river at Adel, Perry and Des Moines: 

 Middle river; North river, Walnut creek; Beaver creek; Des Moines river at Des 

 Moines and Ft. Dodge. 



This is a very abundant fish throughout the area studied. A peculiar feature in 

 relation to its habitat consists in the fact that it commonly is confined to the more 

 rapid portions of the streams and is not often taken in still waters. Its use for 

 food commends it to popular attention. 



Anieiurus molas Rafinesque. — North River; Raccoon river at Des Moines,. 

 Perry and Adel ; Walnut creek, Beaver creek. 



The chief characters of this fish are sufficiently well indicated by its generic and 

 specific names. The very short and broad, or curtailed, caudal fln and its deep 

 blue-black color serves to readily distinguish it from its congeners. Its habits 

 are peculiar in that.it is rarely taken in swiftly flowing or clear water but appears- 

 to thrive best in deep and muddy streams, with slowly moving current, or in the 

 bayous formed by the abandonment of former river channels. In such situations 

 it is both abundant and large. Near the city of Des Moines is an old river 

 channel in which this form is so abundant that a single haul of the seine brought 

 to land several thousands of them. Among the lot thus obtained many were the 

 maximum length for this species, or about twelve inches. The larger specimens- 



* Bulletin United States National Museum, No. XVI, IfeSa. 



