366 TROPICAL AND SOUTHERN FISHES 



appendage ; the European species differing from its Pacific relative not only by its- 

 much superior size, but likewise by the relatively shorter base of the second dorsal 

 fin. Probably the Atlantic species is not uncommon at comparatively great depths 

 off the Irish coast, where, however, its capture is difficult, five egg-purses having 

 been secured which probably belong to this species. The Atlantic specimen was 

 about five feet in total length — a much greater size than is attained by the typical 

 Chimcera monstrosa, of which the normal length is about a yard. 



Lampreys, which, according to modern views, are not really fishes, 

 but form a class (C\^clostomata) of their own, are well represented on 

 the coasts of tropical seas, from which they ascend the larger rivers for the purpose 

 of spawning. Like eels, lampreys never return to the sea from the rivers in which 

 they have spawned ; death being probably due to the exhausting effects of breeding, 

 aided perhaps by a reduced vitality brought about by the labour of carrying 

 pebbles m the sucker-like mouth to form the nests in which the spawn is deposited. 

 Disease developing in the self-inflicted wounds made during the breeding season 

 may be another inducing cause. Very noteworthy is the fact that in one Japanese 

 species (Lapetra mitsurikii) there are two distinct phases, one very much larger than 

 the other, while in both phases the males differ from the females by the smaller size- 

 of the anal fin. 



