THE TEETH OF CETAOEA. 313 



centrically arranged around a vascular papilla, the latter 

 being enormously elongated. The baleen plate is composed 

 mainly of these fibres, which constitute the hairs of its frayed- 

 out edge, but in addition to this there are layers of flat cells 

 binding the whole together, and constituting the outer or 

 lamellar portion. As has been pointed out by Prof. Turner 

 (Proc. Roy. Soc. Edinburgh, 1870), the whalebone matrix 

 having been produced by the cornification of the epithelial 

 coverings of its various groups of papilke, is an epithelial or 

 epiblastic structure, and morphologically corresponds not 

 with the dentine, but with the enamel of a tooth. 



The whole whalebone plate and the vascular ridges and 

 papillae which form it may be compared to the strong ridges 

 upon the palates of certain Herbivora, an analogy which is 

 strengthened by the study of the mouth of young whales 

 prior to the cornification of the whalebone. 



