Lake Maocinkiickee, Physical and Biological Survey 299 



22. Large-mouthed Bass. Micropterus salmoides. 



Fifteen of these fish were obtained for examination during the 

 summer, and in most of them the digestive tract contained noth- 

 ing that could be identified with certainty. From three were ob- 

 tained crawfish, and from one of these and four others the remains 

 of small fish. Five young fry taken in the minnow seine gave bet- 

 ter results. One, 45 millimeters long contained many Cypris, 

 Daphnia, and other entcmostraca, one Chironomus larva, and an 

 Achtheres copepodid larva. Another, the same lengih, contained 

 the same entomostraca and their eggs, and a strange alga. A 

 third, 52 millimeters long, had its stomach nearly filled with amphi- 

 pods. A fourth, 55 millimeters in length contained an Achtheres 

 larva and a lot of indeterminable material. The fifth one, 70 milli- 

 meters long, contained only fish remains. 



All the larger fish and four of the small ones contained cestodes 

 and Acanthocephali ; the fourth small one just enumerated yielded 

 four species of these parasites from the stomach alone. 



Achtheres amhloiJlitis was found on the gill-arches of four of 

 the large fish, and Erga.silns centrarchidaruni on the gill-filaments 

 of four of the smaller ones. 



23. Wall-eyed Pike; "Salmon". Stizostedion vitreum. 

 Twenty-four of these perch were obtained for examination, the 



largest of which weighed four pounds and the smallest a pound 

 and a half. The only thing obtained from their stomachs in the 

 way of food was the remains of small fish, too far digested in every 

 instance to allow of identification. 



They were all badly infested with Acanthocephali, six or eight 

 large specimens being often found in the stomach of a single fish. 

 Trematodes were also common in the stomach and intestines. 

 Ergasilus centimrchidariim in small numbers was found on the 

 gill-filaments of three of the fish. 



No leeches were found on any of the fish, but this is no doubt 

 partly due to the fact that during the summer the walleyes stay 

 in deep water. In the spring when thej^ come into shallow water 

 to breed they are probably as badly infested with leeches here 

 in this lake as they have been found to be elsewhere. 



The author had the privilege of examining 200 walleyes at the 

 Hatching Station at Swanton, Vermont, on the extreme northern 

 end of Lake Champlain, in the spring of 1905. 



With very few exceptions every fish had at least a few leeches 

 somewhere on its body, and from the roof of the mouth of one four- 

 pound female were taken 40 large specimens. 



