74 PETROMYZON. 



but with a light yellowish tinge on the abdomen. 

 The first dorsal fin, like that of the sea lamprey, is 

 separated from the second. To all intents and pur- 

 poses, it is the same fish, — having the character- 

 istic two large teeth, only it is found in ponds and 

 streams so remote from the ocean, that it is next 

 to impossible that it should have had, within cen- 

 turies, any intercourse with the sea, though that is 

 the original seat of their ancestry. 



Birds, in their rapid flights from one section of a 

 country to another, have not only distributed the 

 eggs of fishes and the seeds of plants, but even the 

 living animals themselves. It is in this way, that we 

 are obliged to account, for example, for the ap- 

 pearance of a lamprey in a small pool, hundreds 

 of guiles from the ocean, which has no communica- 

 tion, whatever, with running streams. The wad- 

 ing birds, as the heron, might swallow one of these 

 animals, whose vitality is of so low an order, that 

 it is not necessary for them to breathe a mouthful 

 of water, even for many hours, — and convey it in 

 its intestinal tube, three hundred miles, and if it 

 were voided, where such carnivorous birds would 

 be most disposed to rest, the fish would recover 

 any temporary injury by the journey, — and if it 

 were pregnant, the race would be propagated, and 

 thus the waters of the interior of the country, be- 

 come stocked by a new family of aquatic be- 

 ings. 



