444 Simon Henry Gage 



The ovulation is repeated at intervals until the eggs are all 

 extruded. If during the spawning the lampreys are disturbed 

 so that one or both leave the nest they soon return. After 

 the spawning is completed, however, they leave it for good 

 and a newly arrived pair may utilize it and thus save them- 

 selves much labor. This is proved by catching a pair in a 

 nest and finding the nest occupied by another pair on return- 

 ing some days later. It is also proved by the fact that from 

 the same nest, during the middle and latter parts of the 

 spawning season, one can obtain eggs apparently but just laid 

 and in the earliest stages of development, and embryos 8 to lO 

 millimeters in length. 



The duration of the spawning season for the brook lamprey 

 is about two weeks. They appear earlier than the lake lam- 

 preys and all disappear before the lake lampreys arrive. Fre- 

 quently the lake lampreys utilize the nests of the brook lam- 

 preys as they do the nests of earlier pairs of their own species, 

 as described above The time for the spawning of the brook 

 lamprey usually begins about the 8th of May and lasts till 

 about the 20th. The lake lamprey usually appears about the 

 25th of May and disappears about the first of July, the height 

 of the spawning time being about the loth of June. The 

 time varies from year to year and corresponds in general to 

 the advance of the seasons. 



As one watches these humble creatures with their pigmy 

 brains and observes with what exactitude they recognize that 

 " to rule nature one must obey her," there comes to one the 

 feeling that the germ, at least, of the highest achievement is 

 present in these our lowlj' vertebrate allies and that the abj'ss 

 separating us from them is not so wide after all. If it is urged 

 that all this precision and the resulting efficiency is due to 

 blind instinct then it may be answered that an instinct which 

 guides its possessor to apply the appropriate means to accom- 

 plish a desired end, to overcome difficulties not previously en- 

 countered by the race and guides it to make the most of favor- 

 ing circumstances whether the}' be common ones or those 

 never before utilized, then it must be said that such a guide 

 is a pretty good thing to have after all, and about as valuable 



