102 MAMMALIAN DESCENT. [Lect. IV. 



tliat tlie embryo, before they take place, may be con- 

 sidered as bearing an essentially larval relation to tlie 

 permanent and bigbly modified form. No one need 

 be startled at the term larval, nor at what will 

 seem, perhaps, still more daringly speculative, viz., 

 that this quasi-larval stage has been inherited, and that 

 it was not always ^'ttasi-larval merely. Such forms 

 may have lived, and most probably did live, an open 

 life, with a slow, real metamorphosis ; there is no great 

 difficulty in supposing, also, that the waters brought 

 them forth abundantly, and that they were equal to 

 their aquatic surroundings ; not hesitating to develop 

 gills, when, as yet, lungs were not. 



In this early skull of the Pangolin the likeness to 

 that of the Crocodile at the same stage is seen in the 

 open pituitary space, and in the cartilaginous nodule 

 attached to each pterygoid bone. But, very soon, in 

 this as in all the other Mammalia, the arrest of the 

 primary cartilaginous jaws to form the incus and malleus 

 [anvil and hanwier), and the new hinge made on the 

 projecting spur of the temporal squama, soon mask the 

 essentially Eeptilian character. 



In all the embryos and young of the Edentata I find 

 five vomerine hones, one along the middle, sheathing the 

 base of the ethmoidal wall, and a front and hinder pair 

 of bony centres. 



The front pair, those which are correlated with a pair 

 of retral cartilages growing from the snout to protect 



