198 REPORT OF THE COMMISSIONERS OF 



was found there during the entire spawning season. The reason it was not used was 

 that the bottom of the stream bed there was covered with stones not smaller than a 

 man's hand. These were too large to be readily moved by even the representatives of 

 the larger species of lamprey. Again, a quarter of a mile further down stream, where 

 there was a strong current and an abundance of good water in proper condition, there 

 was not a spawning bed of either species to be found. .A closer examination of the 

 stream bed here showed that this was because there were no stones or pebbles what- 

 ever, although there was an abundance of sand. 



On the other hand, illustration No. 10 shows the great abundance of the spawning 

 beds of the Lake Lamprey at a place where earlier in the season scarcely a bed of the 

 Brook Lamprey was to be found. It was plainly evident that the abundance of the 

 larger-sized species of lamprey and the scarcity of the smaller spawning at this site, is 

 due to the presence of only medium-sized and larger stones here, which are too large to 

 be used by one kind but are of a suitable size to be used in the spawning beds of the 

 other. 



Another difference between them is seen in the number and size of the eggs they 

 lay. The female Brook Lamprey lays from 800 to 1,000 eggs, of a smaller size than 

 those laid by the Lake Lamprey, while the latter lays fully thirty or forty times that 

 number. They also differ in their relative abundance on a single spawning bed. In 

 most instances more than one pair of Brook Lampreys are found on a spawning bed, 

 while with the Lake Lampreys one pair for each spawning bed is the general rule. 

 In fact, the Brook Lampreys appear to be truly gregarious, while the Lake Lampreys 

 show a distinct tendency to be averse to any kind of socialism. This may be due to 

 the degenerate and enfeebled or rudimentary teeth of the former, by which it loses its 

 only weapon of offense and defense, and which may render it docile after the manner 

 that irascible cattle are rendered docile and social, or closely gregarious, by dehorning. 

 It is well known that the habits of the cattle change after they are deprived of their 

 weapons by this process. 



As shown above, through the degeneration of the teeth (see illustrations Nos. 5 and 

 6) the Brook Lamprey is incapable of inflicting a wound, and we have never seen one 

 attack or strike another (excepting for mating) while on the spawning bed ; but we have 

 seen a male Lake Lamprey battle with another for the lordship of a spawning bed which 

 contained a spawning female, and when the first male struck the intruder the latter 

 writhed with all the evidence of pain. It struck back viciously, but with no avail, as it 

 was speedily driven away. While, as a rule, the spawning beds of this lamprey are less 

 than a foot in diameter, we have seen them formed contiguous across a favorable site in 

 the stream in a continuous row or line from ten to fifteen feet long. It is not unusual 

 to see them from two to three feet in diameter and containing from ten to fifteen 



