Chap. XII. FKESH-WATER PRODUCTIONS. 387 



of many kinds, and were altogether 537 in number ; 

 and yet the viscid mud was all contained in a breakfast 

 cup ! Considering these facts, I think it would be an 

 inexplicable circumstance if water-birds did not trans- 

 port the seeds of fresh-water plants to vast distances, 

 and if consequently the range of these plants was not 

 very great. The same agency may have come into 

 play with the eggs of some of the smaller fresh-water 

 animals. 



Other and unknown agencies probably have also 

 played a part. I have stated that fresh-water fish eat 

 some kinds of seeds, though they reject many other 

 kinds after having swallowed them ; even small fish 

 swallow seeds of moderate size, as of the yellow water- 

 lily and Potamogeton. Herons and other birds, century 

 after century, have gone on daily devouring fish ; they 

 then take flight and go to other waters, or are blown 

 across the sea ; and we have seen that seeds retain their 

 power of germination, when rejected in pellets or in 

 excrement, many hours afterwards. When I saw the 

 great size of the seeds of that fine water-lily, the 

 ISTelumbium, and remembered Alph. de Candolle's re- 

 marks on this plant, I thought that its distribution 

 must remain quite inexplicable ; but Audubon states 

 that he found the seeds of the great southern water- 

 lily (probably, according to Dr. Hooker, the Nelumbium 

 luteum) in a heron's stomach ; although I do not know 

 the fact, yet analogy makes me believe that a heron 

 flying to another pond and getting a hearty meal of 

 fish, would probably reject from its stomach a pellet 

 containing the seeds of the Nelumbium undigested; 

 or the seeds might be dropped by the bird whilst 

 feeding its young, in the same way as fish are known 

 sometimes to be dropped. 



In considering these several means of distribution, 



s2 



