TIIK SKELETON OF THE VERTELIIATE HEAD. 1G3 



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

 the pterygoids, Lolow tlie pahatines, 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 ami 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 tui-tle, they 

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

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

 l)ird, hitherto denominated "vomer," are the same bones 

 which in the frog, lizard, and sei-pent, 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 othei-s, along with which they have been examined, 

 exactly as the "bones of liertin," in the lunuan cranium, are to 

 the palate-bones and pteiygoids. 



Tltc Pir-aphcnoidal Ilamal Arch and Ifcrnmctinapophyxi,^ 

 of the FUh. — In the osseous fi.sh a fibrous membrane extends 

 outwards and downwards on each side from the suborbital bar- 



* III the annotated copy the words turtle and tortoisi', whiili ai>]>cjiretl in 

 the original memoir, were deleted. — (Eds.) 



