401 



gorged itself with Cyclops. It had taken no vegetation except a trace 

 of Spirogyra, and nothing of the nature of mud was to be seen in its 

 stomach. In the laboratory, young carp ^ to ^ inch long were ob- 

 served to snap at and swallow large Cladocera and Copepoda, and 

 specimens i to i^/j inch long were seen to attack and swallow, with 

 difficulty, full-sized specimens of Hyalclla knickcrhockcri, 3 to 5 mm. 

 long. In August, 191 o, several young carp i to 2 inches long were 

 fed in the laboratory a mixture of coarse plankton, including Bnto- 

 ■uiostraca, WoMa, etc., and killed after thirty minutes. Specimens ex- 

 amined had eaten greedily of the Bntomostraca, but had taken no 

 JVolfHa or other vegetation. 



2. Apparent preference of fry and fingerliiigs for feeding grounds 

 ■zcifh some bottoni-coz'cring of regcfafion (presumably because of the 

 animal organisms living among the vegetation). — Work with the 

 cheese-cloth seine in Danhole's and Schulte's fields in May, 1910, in- 

 dicated that fry Ys to ;>4 inch long feed by preference very near the 

 bottom. The situations studied were all shallow, i to 2 feet deep, 

 more or less densely filled with short bog-rush, among which was a 

 rich entomostracan plankton. Fry were never observed, szvimming at 

 or near the surface, in open water, as do the fry of l>ass, sunfish, and 

 various native Cyprinid(r. In May and June, 191 1, likewise, it was 

 our experience that the fry were most likely to be found along the 

 very edges of lakes such as Thompson's, Liverpool Lake, etc., in water 

 6 inches to i foot deep, choked with bog rush, algae, or other vegeta- 

 tion. Large numbers were observed feeding on the bottom under ver- 

 itable blankets of alg?e, which had to be lifted before the fry could be 

 seen. At no time did we find carp fry in open water with mud or sand 

 bottom. We found them in Thompson's Lake, May, 191 1, in v.ater as 

 deep as 4 feet, but only where there was a rich growth of vegetation. 

 In Thompson's Lake, May, 191 1, in intertangled algie and Potamoge- 

 ton, reaching from bottom to surface in 4 feet of water, we found 

 them at various levels, from bottom to surface, but those at and near 

 the surface were held up to a great extent by the algae, and were not 

 swimming free. In the search for fingerlings in July and August, 

 1 9 10, when we could find them nowhere else, we were pretty sure of 

 getting them in the narrow Ceratophyllum zone on the west shore of 

 the Illinois River, opposite Quiver Beach. This Ceratophyllum, roll- 

 ing against a mud bank in i to 2 feet of water, was swarming with a 

 small amphipod, Hyalclla knickerbockeri, on which the young carp 

 were feeding. 



