128 



the few specimens which I have stu'lied, I have not attempted such 

 determination, although 1 have reason to believe that most of those 

 examined belong to some species of Minnilus. 



Their food was so far peculiar, as compared with the young of 

 other families, that I will describe in detail that foau'l l)y dissect- 

 ing six specimens under an inch in length. Tlie hrst of these, three 

 eights of an inch long, taken in Fox river on tbe 8 h of July, had 

 eaten only a small Chironomus larva and a single example of Bos- 

 mina. Two specimens, six tenths of an inch long, captured in 

 August, in a creek in Central Illinois, had derived tlieir food from 

 quite different sources. Filaments of Spirogyra and other filamentous 

 Alga", cells of Cosmarium and Closterium, and Cymatopleura and 

 other diatoms, and spores of Ustilago, were the vegetable elements, 

 while the head of a Chironomus larva and great numbers of the 

 ciliate infasorian Engleiui riridis, and a few specimens of Etu/lena 

 acas, represented the animal kingdom. Full half the contents of 

 these intestines consisted of the Protozoa mentioned. A third speci- 

 men of the same length, taken from the Illinois river in June, had 

 derived about eight tenths of its food from Bosmina, the remainder 

 consisting of a small Chironomus larva and a minute larval hydrach- 

 nid. In a specimen seven tenths of an inch long, taken in Macki- 

 naw creek in August, FAiglena viridh was the most abundant object, 

 making about six tenths of the food ; and En<ilena nciis and a species 

 of Phacus also occurred. Various filamentous Algtt, specimens of 

 Closterium and Cosmarium, and numbers of diatoms, were the re- 

 maining elements. In another specimen, taken at the same time 

 and place, about three fourths of an inch in length, fungi and fungus 

 spores amounted to more than half the food, although the same 

 forms of Algie occurred as before, together with a few examples of 

 Eu(ile»a viridis and Diftlugia. A Chironomus larva, a plant-louse, 

 and some other insect not determined, had also been eaten. 



From the above we may conclude that the young Cyprinidne draw 

 almost indiscriminately, for their food supply, upon Protozoa, Algfe, 

 and Entomostraca, differing in this respect from the young of all 

 the other families which I have studied, with the exception of the 

 Catostomidae. It is woithy of note, as a suggestive coincidence at 

 least, that the other families just mentioned which were found to 

 take Entomostraca and Chironomus larvae as their earliest food, 

 Avere all possessed of raptatorial teeth on the jaws when very young, 

 whereas in young suckerfe and Cyprinidae the mouth is unarmed at 

 all ages. 



Group I. 



Intestini' loiij;. Pliarvnirt^il tfctli not lioukt'd. with tiriiidins: surfiKc. 



Campostcafa ANo>rALUM, Raf. Stone Lugger. 



This very peculiar fish is exceedingly abundant everywhere except 

 in the Great L-ikes. I have taken it iu streams of ail magnitudes, 

 from the Illinois liiver to the smallest creeks, but have not yet en- 

 countered it iu Lake Michigan or in stagnant pools. It is com- 

 monest, however, in swift creeks of medium size. 



