478 Siniou Henry Gage 



the lakes and the ocean through the St. I^awrence River, 

 there is no occasion to consider the lake lamprey as a land- 

 locked form at all.* 



While it is true that the natural obstacles are not such as 

 to prevent the immature lampreys from passing to the ocean 

 and then returning when mature to deposit their spawn, the 

 distance inland is greater than undoubted sea lampreys have 

 ever been known to pass ; certainly none have ever been 

 found in Cayuga and Seneca lakes by the writer, and from 

 information obtainable from others none have been seen in 

 any of the lakes or in Lake Ontario.! 



The final and definite proof that the lake lampreys remain 

 permanently in the lakes and do not go to the ocean at any 

 time, has been abundantly obtained during the past iS years 

 by the capture of examples of the adult form of all sizes in 

 the waters of the lake during every month of the 3^ear, while 

 the true anadromous forms are found in the inland waters 

 they are known to inhabit, only when very small and when 

 spawning. 



As to a reasonable hypothesis for the presence of these ios- 

 lated or land-locked lampreys : It is recognized by all modern 

 geologists and physical geographers that the pre.sent contour 

 of the country and the details of the topography of the greater 

 and lesser lake basins with their water courses and ridges are, 

 geologically speaking, only of recent date. Bj' glancing 

 again at the small topographical map (PI. II) it can readily 

 be seen that during the glacial epoch when the basins of the 

 St. Lawrence and of the lakes were filled with ice, the water 

 from the melting ice accumulated and finall}- passed the 

 low elevation south of the lake basin and found its way to the 

 Susquehanna River. Later, as the ice sheet receded, the out- 

 let was through the Mohawk into the Hudson River. Finally 



* The common eel {Anguilla roslrata) is also abundant in the lakes. 

 As it has been determined by recent investigations that the common 

 eel goes to the ocean or to brackish water to spawn and the j-oung re- 

 turn to fresh water to mature, it will be seen that the passage to and 

 from the ocean is not insuperable. 



t I wish to express my indebtedness to the State Game and Fish Pro- 

 tectors who so fully and courteously answered the questions concerning 

 the lampreys of their respective districts. 



