426 Simon Henry Gage 



1878-1879 specimens were submitted to Prof. D. S. Jordan, 

 who designated the lake lamprey as Petromyzon nigricans of 

 I,eseur in the synopsis of the fishes of North America ('82), 

 remarking : " It is possibly only a variety oi P. marinus." 



During the college year, 1885-86, S. E. Meek, one of Pro- 

 fessor Jordan's students, as fellow in zoology in Cornell Uni- 

 versity, made a special study of the fishes of the Cayuga L,ake 

 basin ; and from the interest already aroused in the lampreys 

 of the lake, he joined the writer, during the spring of 1886, in 

 a critical and extended examination of the lake lampreys. 

 Nearly 800 specimens were studied, especially as to external 

 sexual characters and specific relationships. In a joint com- 

 munication before the American Association for the Advance- 

 ment of Science (Gage and Meek, '86) the following points 

 were presented: (a), "The determination of the specific 

 identity of the large Cayuga Lake lamprey and the sea lam- 

 prey ; (b), The determination of the constant presence of a 

 dorsal fold or ridge in the males and of a ventral fin-like fold 

 in the females of [the Cayuga I,ake] Petromyso?i marinus, at 

 the breeding season." 



Jordan and Fordice ('85), in " a review of the North Ameri- 

 can species of Petromyzontidse," remark concerning the 

 Cayuga L,ake lamprey. "We have examined marine ex- 

 amples of this species \_P. marinus^ and also numerous .speci- 

 mens in all stages of growth from the larva to the adult form, 

 collected by Dr. Burt G. Wilder, in Cayuga Lake, at Ithaca, 

 N. Y. Among these are types of Petromyzon dorsatus Wilder, 

 which seems to be merely a land-locked form, not permanently 

 distinct from P. marinus. The characters assumed to dis- 

 tinguish this form from the true marinus are, however, more 

 or less inconstant and not of specific value." 



Even after the extended study of the 800 specimens men- 

 tioned above, there still remained to be settled the question 

 whether or not the external sexual characters of the dorsal 

 ridge in the male and the anal fin-like structure in the female 

 were constant throughout the year or merely seasonal char- 

 acters comparable to so many others known in the animal 

 world. There was also the query whether the American, 



