THE WHALEBONE WHALES 



1179 



transverse processes of the vertebrae, and having no connection with the bodies of 

 the same. The breastbone is composed of but a single piece, to which only one 

 pair of ribs articulate. 



As remarked by Sir W. H. Flower, in the substitution of baleen for Leeth, as 

 well as in the loose connection of the ribs with the backbone and the breastbone, 

 and in the reduction in the size of the latter, the whalebone whales are more special- 

 ized than the other group of Cetaceans; this laxity of connection between the 

 ribs and the other parts of the skeleton, allowing of a greater degree of expansion of 

 the cavity of the chest, and thus permitting a longer submergence beneath the 



THE GREENLAND WHALE. 

 (One-one hundred and fiftieth natural size.) 



water without the necessity of coming up to breathe. On the other hand, in the 

 retention of the double apertures to the nostrils, and in their symmetrically-formed 

 skulls, as well as in the position of a distinct olfactory organ, and certain other feat- 

 ures of their organization, the members of the present group depart less widely from 

 the ordinary type of Mammalian structure than do the existing toothed Cetaceans. 

 The baleen or whalebone, which does not appear until after birth, 

 is composed of a numerous series of flattened horny plates, placed 

 transversely on either side of the palate, and separated from one another by an open 

 space in the middle line. The plates vary greatly in length in the different species, 



Whalebone 



