OBJECTIONS TO THE THEORY 315 



sharper than in the duck. The common goose does not 

 sift the water, but uses its beak exclusively for tearing 

 or cutting herbage, for which purpose it is so well fitted 

 that it can crop grass closer than almost any other ani- 

 mal. There are other species of geese, as I hear from 

 Mr. Bartlett, in which the lamellae are less developed 

 than in the common goose. 



We thus see that a member of the duck family, with 

 a beak constructed like that of the common goose and 

 adapted solely for grazing, or even a member with a beak 

 having less well-developed lamellse, might be converted 

 by small changes into a species like the Egyptian goose 

 — this into one like the common duck — and, lastly, into 

 one like the shoveller, provided with a beak almost 

 exclusively adapted for sifting the water; for this bird 

 could hardly use any part of its beak, except the hooked 

 tip, for seizing or tearing solid food. The beak of a 

 goose, as I may add, might also be converted by small 

 changes into one provided with prominent, recurved 

 teeth, like those of the Merganser (a member of the 

 same family), serving for the widely different purpose 

 of securing live fish. 



Returning to the whales. The Hyperoodon bidens is 

 destitute of true teeth in an efficient condition, but its 

 palate is roughened, according to Lacep^de, with small, un- 

 equal, hard points of horn. There is, therefore, nothing 

 improbable in supposing that some early Cetacean form 

 was provided with similar points of horn on the palate, 

 but rather more regularly placed, and which, like the 

 knobs on the beak of the goose, aided it in seizing or 

 tearing its food. If so, it will hardly be denied that the 

 points might have been converted through variation and 



