Biological Survey — Oswego Watershed 159 



All lampreys lay their eggs in fresh water streams, and the young 

 grow up in the mud banks along those streams. Some of the 

 adults, like the brook lamprey, live all of their life in the streams 

 where they were born; others like the lake lamprey, spend their 

 adult life in fresh-water lakes; but the sea lamprey, as its name 

 indicates, spends its adult life in the ocean. When fully mature, 

 however, it returns to the fresh-water streams to lay its eggs for 

 a new generation. 



Distinction of the Sexes, and Coloration in Lampreys. — In 



the active, predatory life the coloration is in shades of gray. 

 Where the pigment cells are numerous there are black spots, and 

 where fewer, deeper or lighter gray. The fishermen call them 

 spotted lampreys. Sometimes the pigmentation in the dorsal half 

 of the animal is almost uniform, then they appear black or blue- 

 black, or dark brownish. The brook lampreys are more inclined 

 to the browns than the deep blacks. 



During the breeding season the coloration may be black and 

 gray as in the predatory period, or with the lake and the sea 

 lamprey the epithelium may be filled with a golden lipochrome. 

 Then the gold and black give the animal a very striking, and 

 beautiful appearance. Sometimes it is the male that is brilliantly 

 colored and sometimes the female, and sometimes both are almost 

 equally favored by the gorgeous mating costume. This is well 

 shown in the pair of lake lampreys (Plates 1 and 2). The speci- 

 mens for these plates were found in a nest near the entrance of 

 Enfield creek into the main inlet of Cayuga lake, May 31, 1927. 

 The distance up the valley from the lake is about seven kilometers 

 (4 miles). 



During the free-swimming, predatory life of the lampreys the two 

 sexes are so nearly alike that they cannot be distinguished except 

 by dissection, and even then, except near the breeding season, it is 

 difficult with the naked eye because the gonads appear so much 

 alike. That is, to the naked eye the eggs and the sperm-cysts are 

 nearly of the same size, and give the gonads the same general 

 appearance. A microscopic examination, however, shows with the 



Acknowledgements : For information like that in the following report, help 

 must be gleaned from many sources: fishermen, naturalists, much personal 

 observation, books and periodicals. In the text I have noted special pieces of 

 help, but would like here to express my thanks to some not there men- 

 tioned: To Dr. J. B. Sumner, biochemist, for assistance with the antieoagu- 

 lating secretion of the buccal glands; to Dr. and Mrs. W. A. Clemens, Pacific 

 Biological Station, for supplying me with the buccal secretion of the Pacific 

 lamprey, Entosphenus, and for abundant material of both adults and young; 

 to Dr. Vera Mather, University of Oregon for the adults and young of the 

 large Entosphenus of the Willamette river valley; to Dr. B. F. Kingsbury, 

 to Marguerite and Ernest Kingsbury for help in securing lampreys from 

 Cayuga and Seneca lakes; to F. W. S. Scudder for lampreys from the Con- 

 necticut river valley; to Dr. J. C. C. Loman of Amsterdam for adult and larval 

 brook lampreys from Holland; to Drs. P. Okkelberg and C. L. Hubb.s of the 

 University of Michigan for brook lampreys from that region; and finally to 

 my sister, Dr. Mary Gage Day, for aid with the buccal gland secretion, and 

 for critical reading of the manuscript. 



