210 BULLETIN OF THE UNITED STATES FISH COMMISSION. 



this species attacking fish, or taking other food in the adult state, the information will be 

 very acceptable. Professor Gage has found transforming larva? the last of October, 

 and full adults on the spawning-beds as early as the 2<>th of April. Their transforma- 

 tion is doubtless completed before midwinter. 



Some very interesting "Notes on the spawning habits of the brook lamprey (Petro- 

 myzon icilderi)" have been contributed by Bashford Dean and F. B. Simmer (N. Y. 

 Ac. Sci., vol. xvi, December 9, 1897). The authors compare their dates with recorded 

 dates for this region, and conclude that "the spawning season of our local (New York 

 City) lamprey is thus found to be nearly a month earlier than at Cayuga Lake," but 

 to draw accurate conclusions dates in the same year should be compared. In 1897 the 

 brook lamprey was found on beds here on April 30. This makes a difference of 14 

 days instead of 30 days between New York City and this region. These two species 

 of lampreys are apparently identical in places of spawning, habitat of larva?, and 

 observed external appearances (i. e., specific determinations in the ammoccetes stage 

 are impossible), but the brook lamprey spawns from one to two weeks earlier than the 

 lake lamprey. 



Plate 10 shows one of the lake lampreys attached to a common white sucker 

 (Catoatomus commersonii), which is also pierced by lamprey marks near both its 

 ventral and pelvic fins, the body wall being entirely cut through by these blood- 

 suckers, and the abdominal cavity penetrated. This illustration is from a photograph 

 of fresh specimens, under water, taken with a vertical camera, by Prof. S. H. Gage, 

 at Cornell University. Professor Gage and Dr. Wilder have done more work with 

 the lampreys of this region than have any other persons, and it is from Professor 

 Gage's article on " The lake and brook lampreys of New York," in the Wilder Quarter 

 Century Book, 1893, that much information is taken for the present paper. The other 

 illustrations are from photographs of specimens collected in Cayuga Lake or its inlet 

 by persons at Cornell University, and were made for the purpose of showing some 

 special features of the habits of this enemy of our fishes. 



The lamprey is similar to the frog and most other amphibians in the fact that 

 from the young stage to the adult it passes through a metamorphosis slightly compar- 

 able with the change of a tadpole into a mature frog. Its full life-history, as deter- 

 mined by Professor Gage, is, briefly, as follows: 



The adult passes about three years in the lake, living exclusively by sucking the 

 blood from living fishes, most of which are good food-fish. In the springtime, about 

 the middle of April, apparently, they start out independently from the various points 

 of the lake, each one forsaking its prey and swimming vigorously or stealing a ride 

 by attaching to the bottom of some boat moving in the right direction. On they go 

 until the current of the inlet gives them the clue, and they follow it. Frequently, 

 also, ordinary fishes bound on the same errand throng the streams, and then the lam- 

 preys, with their inherent desire to be taken care of by the labor of others, fasten to 

 the larger fishes and are carried along up the stream. It not infrequently occurs 

 that from the natural inclination of the stream, or from some of man's obstructions, 

 there are rapids or dams to be surmounted. Nothing daunted, the lamprey swims up 

 just as far as possible by a tremendous eifort, grasping a stone or other object so that 

 he can not be carried* downstream again, rests for a while, and then, by a powerful 

 bending and straightening of the serpentine body, a leap is made in the right direc- 

 tion, and what is gained is saved by again fastening the mouth to a fixed object. 



