74 MR. HOGG ON THE MODES OF 



studied and explained — and this is, tlie mode of distribution of the 

 species of many of our fresh-water fishes. It is well ascertained 

 that in certain mountain and alpine streams and lakes there are 

 to be seen trout and other fish — the presence of which it is most 

 difficult to account for. Every practical Botanist knows, to his 

 surprise, that in out-of-the-way districts a specimen or two of a 

 rare plant sometimes occurs, which the winds cannot have carried 

 there; but in all probability its origin can only be accounted for 

 in those isolated spots by the seed having been dropped there by 

 birds. So it strikes me that the problem of how trout, and other 

 like fish, were originally introduced into far distant alpine streams 

 and isolated mountain lakes and waters — especially in those 

 pieces of water, or tarns, that now fill the craters of extinct vol- 

 canos, and which are of comparatively recent date, might be 

 naturally solved in an analogous manner; — that is to say, by 

 water-birds conveying accidentally, or perhaps intentionally, to 

 their young to those places, certain water-animals whereon they 

 feed, taken from some distant river or lake in which that species 

 of fish abounds, and which water-animals may have gorged them- 

 selves with the spawn, or impregnated ova, of that particular 

 species, and some of whose ova might be thus conveyed unin- 

 jured — at least, uninjured in a vital degree — and falling from these 

 animals, are subsequently hatched in their new locality ; after- 

 wards the fry would continue to " increase and multiply." This 

 I merely now mention (since I do not know that it has occurred 

 to any one else) to the Zoologists present, as a possible mode of 

 accounting for the dispersion of certain kinds of fresh-water fish 

 in such extreme and elevated localities, and the solution of which 

 is a problem of much difficulty as well as interest." 



After I had finished reading this paper, I remarked that I did 

 not consider it likely that aquatic animals could void, with their 

 fceces, the impregnated ova of fishes after being passed through 

 their stomachs and intestines in a sufficiently uninjured state, so 

 as to be certain of producing the fry, but that I chiefly alluded to 

 those animals having disgorged the ova from their mouths after 

 having been carried to those distant waters or lakes by different 

 kinds of water-birds. And during the discussion that ensued, it 



