BY R. BROOM. 549 



is the process, or even a part of it, ever formed from a distinct 

 centre. 



In Marsupials, so far as they have been examined, the palatine 

 process is never distinct. 



If the results of Kitchen Parker's work on the development of 

 the skull in the Edentata and Insectivora were fully confirmed 

 there would be no longer any doubt that in a number of forms 

 at least the palatine process is a distinct element which at only 

 a comparatively late stage in development unites with the pre- 

 maxillary. Parker, in fact, seems to consider this to be the 

 normal condition, since he states that the " anterior paired 

 vomers are very constant in Mammals." He describes distinct 

 "anterior vomers " in the following forms : — Tatusia hybrida, T. 

 peha, Dasypus villosus, ChoIo2?us didactylus, Manis brevicaudata, 

 Orycteropus capensis, Eriyiaceus europceus, and Bhynchocyon 

 cernei. In Centetes^ Hemicentetes, and GaleopitltecvSj Parker 

 apparently satisfied himself that there are no distinct "anterior 

 vomers." In the mole and shrew the " anterior paired vomers " 

 are stated to be "probably connate with the premaxillary." 



When one considers what a small structure the palatine process 

 is even in the adult animal, and that the greater part of Parker's 

 results were obtained by the dissection of small embryos, one 

 hesitates in accepting as final the results of even such a marvellous 

 minute anatomist as Parker. And the hesitation becomes greater 

 when one finds Parker on one page contradicting a statement 

 made only a few pages before. Thus, on page 166, we are told 

 that the anterior paired vomers of the mole " are very slightly 

 separated from the palatine processes of the premaxillaries," and 

 on page 179 that they have a "doubtful existence independent 

 of these processes." 



I regret that I have not had at my disposal embryos of any of 

 the Edentates studied by Parker ; but in young Hedgehogs, 

 corresponding to Parker's 4th and 5th stages, I have been unable 

 to find any distinct " anterior vomers." Recently I made a series 

 of sections of the snout of a foetal Macroscelides proboscideus 

 (head length 15*5 mm.) — a form closely allied to Rhynchocyon, 



