Biological Survey — Oswego Watershed 161 



greatest clearness the difference between the single ova and the 

 multitude of young sperms in the sperm-cyst. 



There is one structural feature that distinguishes the male in all 

 forms during the breeding season. It is the greater length of the 

 genito-urinary tube in the male. With the brook lamprey this is 

 very striking (Fig. 2), though not so marked in the sea and lake 

 lamprey. In the female there is a fin-like fold developed between 

 the genito-urinary opening and the caudal fin in all the forms, and 

 with the brook lamprey from Cayuga lake inlet, at least, there is 

 an oedema in the second dorsal fin which makes its cephalic edge 

 very thick. Sometimes, especially rather late in the spawning 

 time, this oedema is often suffused with blood, making a brilliant 

 scarlet spot in the fin shown by the dark shading in the dorsal fin 

 (Fig. 2, No. 3). 



With the lake and the sea lamprey there is a very striking growth 

 in the male during the spawning season. This is a rope-like ridge 

 along the back between the head and the first dorsal fin. It is also 

 found in the sea lampreys on the spawning beds, but it may be 

 lacking earlier when they are going up the river, as was shown by 

 specimens the first of the season that were going up the fishway at 

 Lawrence, Mass, Those at the end of the season had a well marked 

 ridge when they reached the fishway. 



Kinds of Lampreys in New York. — In the waters of New York 

 State there are three, possibly four, kinds of lampreys: 



The large sea lamprey, which during the spawning season 

 is found in the rivers and tributary streams connected directly 

 with the ocean. 



The lake lamprey, about half as long as the sea lamprey. 

 It is found in some of the larger lakes during the entire year, and 

 in the streams entering: those lakes during the spawning time 

 (Plates 1, 2 and Fig. 1)\ 



The brook lamprey, less than half as long as the lake 

 lamprey. It is found during its entire life in the brooks, never in 

 the lakes (Figs. 1, 2). 



The silvery lamprey (Ichthyomyzon) about three-fourths the 

 size of the lake lamphrey, is reported as present in Lake Erie. 

 The writer has made no personal observations on this lamprey. 



Up to the present the different lampreys have been found in the 

 following waters of the State : 



(A) The large sea lamprey (Petromyzon marinus). (1) In the 

 Susquehanna river. Personal knowledge, and abundant informa- 

 tion given by friends, naturalists and fishermen. 



(2) The Delaware river and its branches. Adults furnished by 

 D. F. Hoy, Registrar of Cornell University ; larvae supplied by 

 A. S. Hazzard and information given by J. R. Greeley. 



(3) The Hudson river* and its branches. Information given by 

 a resident of the Hudson river valley some years ago. 



* DeKay, J. E. Zoology of New York, or the New York Fauna. Part 3, 

 379. Albany 1842-44. 



