286 MISCELLANEOUS OBJECTIONS TO THE [Chap. VIL 



ningof such useful development?" In answer, it may be 

 asked, why should not the early progenitors of the 

 whales with baleen have possessed a mouth constructed 

 something like the lamellated beak of a duck? Ducks,- 

 like whales, subsist by sifting the mud and water; and 

 the family has sometimes been called CriUatores, or 

 sifters. I hope that I may not be misconstrued into say- 

 ing that the progenitors of whales did actually possess 

 mouths lamellated like the beak of a duck. I wish only 

 to show that this is not incredible, and that the immense 

 plates of baleen in the Greenland whale might have been 

 developed from such lamellffi by finely graduated steps, 

 each of service to its possessor. 



The beak of a shoveller-duck (Spatula clypeata) ifl 

 a more beautiful and complex structure than the mouth 

 of a whale. The upper mandible is furnished on each 

 side (in the specimen examined by me) with a row oi 

 comb formed of 188 thin, elastic lamellae, obliquely be- 

 velled so as to be pointed, and placed transversely to the 

 longer axis of the mouth. They arise from the palate, 

 and are attached by flexible membrane to the sides of the 

 mandible. Those standing towards the middle are the 

 longest, being about one-third of an inch in length, and 

 they project .14 of an inch beneath the edge. At their 

 bases there is a short subsidiary row of obliquely trans- 

 verse lamellae. In these several respects they resemble 

 the plates of baleen in the mouth of a whale. But 

 towards the extremity of the beak they differ much, as 

 they project inwards, instead of straight downwards. 

 The entire head of the shoveller, though incomparably 

 less bulky, is about one-eighteenth of the length of the 

 head of a moderately large Balaenoptera rostrata, in 

 which species the baleen is only nine inches long; so 



