The Cyclostomes, or Lampreys E77 
find unsurmountable obstac’es in their way, such as vertical 
falls or dams, they turn around and go down-stream until they 
find another, up which they go. This is proved every spring 
by the number of adu't lampreys which are seen temporarily 
in Fall Creek and Cascadilla Creek. In each of these streams, 
about a mile from its mouth, there is a vertical fall over 
thirty feet in height which the lampreys cannot surmount, and 
in fact they have never been seen attempting to do so. After 
clinging with their mouths to the stones at the foot of the 
falls for a few days, they work their way down-stream, care- 
Sine 
Fie 124.—Kamchatka Lamprey, Lampetra camtschatica (Tilesius). Kamchatka. 
fully inspecting all the bottom for suitable spawning sites. 
They do not spawn in these streams because there are too many 
rocks and no sand, but finally enter the only stream (the Cayuga 
Lake inlet) in which they find suitable and accessible spawn- 
ing sites. 
“The three-toothed lampreys (Entosphenus tridentatus) of 
the West Coast climb low falls or rapids by a series of leaps, 
holding with their mouths to rest, then jumping and striking 
again and holding, thus leap by leap gaining the entire distance. 
“The lampreys here have never been known to show any 
tendency or ability to climb, probably because there are no 
rapids or mere low falls in the streams up which they would 
run. In fact, as the inlet is the only stream entering Cayuga 
Lake in this region which presents suitable spawning condi- 
tions and no obstructions, it can be seen at once that all the 
lampreys must spawn in this stream and its tributaries. 
“Tn ‘running’ they move almost entirely at night, and if 
they do not reach a suitable spawning site by daylight, they 
will cling to roots or stones during the day and complete their 
journey the next night. This has been proven by the positive 
