20 UNIVERSITY OF WISCONSIN STUDIES 



Chaetostomus pearsei Eigenmann, Coroncho 



Rio Castaiio, July 16; number examined, 10; lengths 111-86, 

 ave. 93. Food: bottom mud and sand, 100. 



This sucker-like catfish lives in the swift boulder-filled 

 streams with sandy bottoms. It clings to the under side of 

 rocks by means of its mouth and feeds largely on bottom mud. 



Creagrutus beni Eigenmann, Sardina 



Isla del Euro, July 12; number examined, 10; lengths 32-25, 

 ave. 28. Food: midge pupae 3.8; snails 96.2. 



This little sardina, caught on the same beach as the Astyanax 

 bimactdatus taken in this locality, had eaten quite different 

 foods. 



Crenidchla geayi Pellegrin, Mataguaro 



Isla del Euro, 2 m., July 9; number examined, 5; lengths: 

 146-130, ave. 139. Food: fish 10.5; snails 52; Planorbis 37.5. 



Isla del Euro, 11 m., July 10; no. ex., 2; lengths: 126, 135. 

 Food: (1 empty) fish 100. 



Isla del Euro, 7 m., July 10; no. ex., 2; lengths: 147, 148. 

 Food: snails 100. 



Rio Castaiio, July 27; no. ex., 2; lengths 159, 56. Food: 

 unidentified insect larvae 90; chironomid larvae 10. 



This fish feeds largely on snails, fishes, and insect larvae. 



FIG. 3. The cula, cnrhnalus argenlem 



