546 MAMMALIAN AND REPTILIAN VOMERINE BONES, 



In 1879 Albrecht (1) published a paper dealing with the 

 ossification of the premaxillary bone, and advanced some reasons 

 for believing that this bone is a complex element, its palatine 

 process being frequently formed from a distinct centre. In a 

 later paper he advocated the homology of the dumbbell-shaped 

 bone of Omithorhynchus with the palatine process of the pre- 

 maxillary in the higher mammals. 



In 1884 Bland Sutton (2) communicated a paper to the Zoolo- 

 gical Society of London mainly on the question under consideration. 

 In it he not only held that the palatine process is a distinct 

 morphological element, but that it is the homologue of the 

 so-called "vomer" of the Ichthyopsida, and, further, that the 

 mammalian vomer has its homologue in the " parasphenoid " of 

 the lower forms. 



In 1885 Turner (3), writing on the homology of the dumbbell 

 bone of Omithorhynchus, came to the conclusion that it is the 

 homologue of the palatine process of the premaxillary. 



In the same year Kitchen Parker (4) published his magnificent 

 monographs on the development of the skull in the Insectivora 

 and Edentata. In a number of forms he found evidence of the 

 palatine process being developed as a distinct element. To this 

 element he gave the name of "anterior paired vomer," and 

 recognised it to be the homologue of the paired "vomer" of the 

 Lacertilia and Ophidia. In many animals he also recognised the 

 existence of a pair of posterior or lateral vomers. Of Rhynchocyon 

 he says : — "There are here five vomerine bones, as in the Hedgehog 

 and Armadillo. . . , The two antero-lateral vomers are the 

 largest I have seen as yet, reminding one of their large cupped 

 counterparts in the Ophidia and Lacertilia. . . . The narrow 

 hind part of the main vomer is partly hidden by the two large 

 postero-lateral vomers." The Marsupials, Parker considers, have 

 "many separate vomers" — the genus Cuscus having as many as 

 ten. It may be remarked, however, that these observations of 

 Parker's require confirmation. 



In 1891 Howes (6) read a paper before the Zoological Society 

 of London on the peculiar condition of the vomer in the Caiman. 



