136 ON THE MORPHOLOGICAL CONSTITUTION OF 



this transverse commissure above, the combined ento-ptery- 

 goids below, and the lower ends of the descending ethmoido- 

 frontal processes laterally, is occupied by a prolongation for- 

 wards of the cartilaginous bar-like pre-sphenoidal centrum. 



If the bones hitherto considered by comparative anatomists 

 as the " palatines" in the crocodilian, are in reality the neu- 

 rapophyses of its ethmoidal sclerotome, the question arises 

 Where are the actual palate-bones ? This question comes to 

 be examined in the sequel, when the haemal arch of the pre- 

 sphenoidal sclerotome, of which these bones are elements, is 

 , under consideration. At present I may state that the study 

 of the crania of the bird, lacertian, and ophidian, has led me 

 to recognise as the palate-bone that bone which Cuvier was 

 induced to consider peculiar to the lizard and serpent, and 

 named "os transverse" or "pterygoide externe;" and which 

 Professor Owen also names ecto-pterygoid. 



The Ethmoidal Neural Arch and Centrum in the Lacer- 

 tians. The maxillaries of the typical lacertians are invariably 

 connected above to the so-called pre-frontals. These pre- 

 frontals are widely separated from one another by the anterior 

 extremities of the so-called " principal frontals," which pass 

 forward, and bound laterally the divided or undivided nasals. 

 The pre-frontals bound the anterior superior angles of the 

 orbits, sending downwards on each side a plate which sepa- 

 rates the orbit from the nasal cavity, is more or less intimately 

 connected with the so-called " double vomer," and with the 

 so-called " palatines." I shall, in the sequel, state the grounds 

 on which I hold the " palatines " of the lizard, ophidian, and 

 amphibian, to be its ento-pterygoids, and to be the homologues 

 of the bone or bones which in the bird are considered as the 

 " vomer." I believe the " transverse bones" of the lizard to be 

 actually its palate-bones, pushed backwards and outwards by 

 the greatly-developed ento-pterygoids, and of its so-called 



vomer" of the lizard consists of two 



