The Lake and Brook Lampreys of Nerv York 425 



might be considered generic or at least specific ; and Professor 

 Wilder suggested to his special class, before which the speci- 

 men was brought for study and comparison, that if the peculi- 

 arities noted in this first specimen were found constant and 

 characteristic of the lake lamprey one might consider it a dis- 

 tinct species at least and give it the specific designation of 

 Petromyzoii dorsatus, from the dorsal ridge. But believing 

 that the admonition to " prove all things and hold fast that 

 which is good ' ' should be followed in science as well as in 

 philosophy, publication was reserved until other specimens 

 could be obtained to show whether the first was typical or a 

 mere sport or transient variation from the truly typical form. 



It fell to the writer, then student assistant to Professor 

 Wilder, to prosecute the search for other examples of the lake 

 lamprey and to aid in the final solution of its life history and 

 systematic relationship, the work being constantly forwarded 

 by the advice and encouragement of Professor Wilder, as well 

 as by the freest use of his personal notes and drawings. 



In prosecuting the investigation almost no aid was obtained 

 from the lake fishermen. All they knew about the lampreys 

 was that they were sometimes caught clinging to other fishes. 

 One man, however, living near the inlet, brought to the labor- 

 atory six larvas and stated how they were obtained. He also 

 said that the large ones went up the inlet in the early .spring. 

 By diligent inquiry of people living near the inlet, information 

 was obtained so that in the spring of 1876 the explorations of 

 the inlet were successful and the adult ones were found spawn- 

 ing, and the larvee were found in the sand banks along the 

 edges of the stream. Of the seven large lake lampreys caught, 

 five possessed the dorsal ridge so characteristic of the first one 

 obtained. Upon dissection it was found that the ridged ones 

 were males and those without the ridge females, so that from 

 this time on it was exceedingly easy to determine the sexes in 

 fresh specimens by this feature alone. Alcoholic specimens 

 which had been caught in the breeding .season were far less 

 easily separated into the two .sexes by this sign since the body 

 was badly shrunken in alcohol, and the females so preserved 

 often appeared to have nearly as large a ridge as the males. In 



