THE SKELETON OF THE VERTEBRATE HEAD. 163 



elongated in the same direction ; and if the outer margins of 

 the pterygoids, below the palatines, were to meet in the mesial 

 line, the latter would be forced backwards and outwards ; so 

 that, still retaining their connections with the pterygoids and 

 maxillaries, but leaving those with the " vomer " in front and 

 internally to abut against the malar behind and externally 

 the palatal aspect of the skull of the tortoise would present 

 the arrangement of the corresponding region in that of the 

 crocodile, the palate-bones assuming the form and relations 

 of " transverse bones." 



If to the skulls of the tortoise, turtle, and crocodile, those 

 of a serpent, a lizard, a frog, and an ostrich be added, it 

 will be observed that the palate-bones have disappeared in 

 the frog ; that they have assumed the form and relations of 

 " transverse bones " in the lizard, crocodile, and serpent , 

 that they are essentially " transverse bones " in the struthious 

 bird, while in the tortoise, but especially in the turtle, they 

 present the mammalian (?) character and form. It will also be 

 observed, that the bones in the turtle, tortoise, crocodile, and 

 bird, hitherto denominated "vomer," are the same bones 

 which in the frog, lizard, and serpent, are named "palatals," 

 the term " vomer " being applied in these animals to those two 

 bones collectively, which are situated under the ethmoidal 

 portion of the skull. It will also be noted that the bones 

 called "vomer" in the* crocodile and bird, and the bones 

 called " palatals " in the frog, lizard, and serpent, are related 

 to the others, along with which they have been examined, 

 exactly as the " bones of Bertin," in the human cranium, are to 

 the palate-bones and pterygoids. 



The Pre-sphenoidal Hcemal Arch and Hcemactinapophysis 

 of tlie Fish. In the osseous fish a fibrous membrane extends 

 outwards and downwards on each side from the suborbital bar- 

 In the annotated copy the words turtle and tortoise, which appeared in 

 the original memoir, were deleted. (Eos. ) 



