440 Simon Henry Gage 



addition of pigment whicli appears in the cells of the epider- 

 mis, the pigment of the corium remaining about the same. 

 This pigment is yellowish and between the darks spots the 

 color instead of the usual dull gray appears a bright yellow, 

 in some almost golden, thus giving a very striking and hand- 

 some appearance. As is common in the lower forms, this 

 coloration is more marked in one sex than in the other, but it 

 is a curious and so far inexplicable fact that some years it 

 is the male that appears in the gorgeous dress while dur- 

 ing other years it is the female. For example, during the 

 present year the females of both Cayuga and Seneca lakes 

 were brighter by far than the males, while in i8S6 when 

 special note was made of it, it was the males that were more 

 brightly colored. 



So far as comparisons are possible the sea lamprey appears 

 to undergo the same changes preparatory to spawning that 

 the lake lamprey does. The specimens personally studied 

 were on their way to the spawning ground and had not 

 reached the same and the changes were not yet completed, 

 but the ridge becomes so prominent during spawning that it 

 has been noticed by fishermen. 



With the brook lamprey the changes in the liver are like 

 those occurring in the lake lamprey. The change in the ali- 

 mentary canal may not be quite so striking as with the lake 

 lamprey. Sufficient material out of the breeding season has 

 not yet been secured to settle that question. In the male the 

 only observed external modifications are the apparent fusion 

 of the dorsal fins, and the considerable elongation of the uro- 

 genital papilla. With the female there is the marked anal 

 notch and an apparent anal fin but it is not connected with 

 the caudal fin. 



The very striking appearance in the female is due to the 

 swelling in the second dorsal fin thus filling the space between 

 the two. At the first of the season this is merely an oedema, 

 which appears light or semi-translucent, but later, in many 

 cases, it becomes infiltrated with blood and is bright scarlet 

 (PI. IV, fig. 11-14). 



No dorsal ridge is developed in either sex, and apparently 

 'the general coloration of the body is unchanged. 



