CYCLOSTOMATA 



427 



merit, or attached to stones by the buccal funnel. In the spring 

 the Sea-Lamprey ascends the rivers to spawn, and, after deposit- 

 ing its eggs in furrows which it excavates in the river-bottom, 

 it returns to the sea. The river-Lampreys spawn in the smaller 

 streams and brooks. The North American Brook -Lamprey, 



FIG. 243. Spawning of the Brook-Lamprey (P. wilderi). On the right side of the figure 

 a male is attached to the head of a female. (From Bashford Dean and F. B. 

 Sumner. ) 



Petromyzon (Lampetra) wilderi, which is found in the neighbour- 

 hood of New York, deposits its eggs on the gravelly bottom of 

 a brook, in a small gravel-filled hole lying between a number 

 of large rounded stones * (Fig. 243). In the vicinity of the 

 " nest " some ten to twelve Lampreys congregate, the males, 

 however, being much more numerous (five to one) than the 



1 Bashford Dean and F. B. Sumner, Trans. N. Y. Acad. Sci. xvi. 1897, p. 321. 



