480 HOMOLOGY OF PALATINE PROCESS, 



distinction between this bone and the palatine process of the 

 premaxillary he has involved himself in contradiction. In his 

 beautiful sections of the head of the ftetal Tatusia he shows the 

 supporting bones of Jacobson's cartilages, and in his description 

 of section 7, says : — ^" The cartilages [protecting Jacobson's organs] 

 themselves have an osseous counterpart protecting them on the 

 inner side and having their shaj)e and direction; these are the 

 anterior paired vomers (v'), bones well known for their large 

 development in the Opliidia and Lacertilia " He further recog- 

 nises that these are not parts of the true vomer, and evidently 

 considers them as quite distinct from the premaxillary. In his 

 description of the head of the young Erinareus, he further refers 

 to the intimate association of the recurrent cartilages and their 

 supporting bones or anterior paired vomers. In referring to the 

 recurrent cartilages as seen in the dissected skull of the 3'oung 

 embryo, he says : — " Each leafy part is supported by a bone the 

 form of which it dominates, so that each tract is also hollow on 

 the face that looks towards the cur^'ed inner edge of the cartilage; 

 it lies on the inside, back to back to its fellow : these are the 

 front paired vomers, and answer to the paired ^^omers of the 

 Snake and Lizard among the Reptiles." These bones which he 

 calls " anterior paired vomers " are almost without doubt the parts 

 which, becoming anchylosed with the premaxillaries, form their 

 palatine processes. Parker, however, seems to consider that there 

 are palatine processes in addition to the anterior vomers, but 

 as the cartilages of Jacobson at their anterior part are in contact 

 with the body of the premaxillary there is reall}^ no space for a 

 palatine process distinct from the ossification in connection with 

 Jacobson's cartilage, and if in any form there appears to be a 

 palatine process in addition to an anterior vomer it is probably 

 due to the anterior portion of ossific tract of Jacobson's cartilage 

 becoming ossified by invasion from the premaxillary. 



A study of the comparative anatomy of the prenasal region 

 gives very strong confirmatory evidence that the bone supporting 

 the cartilage of Jacobson is not morphologically a j^art of the 

 premaxillary, though generall}^ anchylosed with it. 



