244 BULLETIN OF THE BUREAU OF FISHERIES. 



insects, and find these most plentiful within the vegetation areas. Here the common 

 sunfish finds snails and the bluegill plant tissues. The two species of Nolropis might 

 feed on plankton outside the vegetation, while the bullhead, rock bass, and large- 

 mouthed bass might, like the pike and small-mouthed bass, obtain fish without restrict- 

 ing themselves to the vegetation. Food alone does not appear to limit these forms to 

 the vegetation. 



In addition to food, the seven smaller forms (excluding Ameiurus, Ambloplites, and 

 Micropterus) find within the vegetation a refuge from certain enemies, chiefly pike and 

 small-mouthed bass. Within its mazes rapid flight is much easier for a small form 

 than rapid pursuit by a larger enemy. 



The breeding habits of one of the forms in our list (the spot-tailed minnow) is 

 unknown. The writer is familiar with the breeding habits of the remaining forms, and 

 the papers of Hankinson (1908) and Shelford (191 1) contain references to some of them. 

 Two species (the log perch and the common shiner) breed on plant-free sand or gravel. 

 A third, Percopsis, according to the unpubHshed obser^-ations of Doctors A. H. Wright 

 and A. A. Allen, of Cornell University, to which reference is made by their permis- 

 sion, breeds "in swiftly running water and over a stony bottom." The common 

 sunfish also may breed on gravel bottom. Four species (bullhead, rock bass, bluegill, 

 and large-mouthed bass) lay their eggs, by preference, in nests made by exposing the 

 fibrous roots of water plants. The bottom material removed in making the nests may 

 be sand, marl, muck, or mud, but the essential of the nests is the rootlets which form its 

 bottom. The eggs of the sunfish, rock bass, and bluegill adhere to the rootlets. Those 

 of the bullhead lie free, united in masses. The bullhead, since its eggs are not adhesive, 

 may make its nest in situations in which rootlets do not occur, but in the writer's expe- 

 rience these nests are always in vegetation. The common sunfish also makes a nest, the 

 bottom of which is sometimes gravel but more often rootlets. The perch, too, commonly 

 deposits its masses of eggs amongst vegetation, although when adult it wanders far 

 beyond the vegetation. Thus there are 6 of the 10 forms that require vegetation as 

 a part of their breeding environment {Ameiurus , usually; Ambloplites; Lepomis, usually; 

 Eupomotis, usually; M. salmoides; Perca). In some of these forms the relation of the 

 breeding habits to vegetation is not at first apparent. Thus Lepomis pallidus is often 

 found breeding where there seems to be no vegetation, but in such cases closer inspec- 

 tion will show that its eggs are laid on the rootlets of bulrushes which are so near the 

 denser vegetation as to afford the fish a ready retreat into it. The same is often true of 

 the large-mouthed bass and the common sunfish. 



Of the 10 forms included in our vegetation community we may repeat that all 

 obtain food in the vegetation. Although some of them might obtain it elsewhere it is 

 doubtful whether they could obtain it as well. At least four of these probably need 

 the vegetation for protection (the two species of Notropis, Percopsis guitatus, and Percina 

 caprodes). This need is scarcely less in the bluegill, the sunfish, and the perch, and in 

 the young of the other forms. The two species of Notropis are not bottom forms. 

 While they might obtain plankton food outside the vegetation, they would be very 

 conspicuous there and could scarcely long escape their enemies. Percopsis and Percina 

 are bottom forms and would more readily escape detection outside the vegetation. 

 It is possible that they may wander to some distance from it. The relation of these 

 10 forms to the vegetation is summarized in table ix. 



