DEVELOPMENT OF THE SKULL IN THE MAMMALIA. 69 
perfectly toothless type of Mammal seems to be a monster; and to be sans teeth is to 
be sans everything. 
In the Snapping Turtle or the Macaw the massiveness of the face makes no 
difference in the morphology of the type ; here also, in this little toothless arboreal 
Anteater, the bird-likeness of the face is a very thin mask to its true nature as a low 
Eutherian Mammal; the whole result is but a faint and feeble imitation of the face 
of the feathered and winged Edentate. 
Yet the result of this slow secular “drawing” of the teeth is very curious and 
instructive (see Plate 10), and the result in this quasi-senile creature is to form a skull 
like a small gourd or a flask. But this lageniform skull is flat on one side, and bent 
downwards towards that flattened side. That is the wnder surface (Plate 10, fig. 1) ; 
here we see a small, short snout, with lateral nostrils (a@/.n., e.n.), quite like that of 
the Sloths, but more slender. 
The basal part of the premaxillaries (pz.) is a small subtriangular tract ; the right 
and left bones are separated by the width of the base of the nasal septum (fig. 7, s.7.). 
Where they diverge, behind, there the maxillaries (ma.) begin to converge ; in the fore 
part of their palatine plate there is then left a lozenge-shaped interspace, and here we 
see the two front paired vomers, small pyriform ossicles (fig. 10, v’.), lying parallel 
with their pointed end forwards. The hard palate is very much sculptured and 
perforated, two-thirds of it belongs to the maxillaries, and one-third to the pala- 
tines (pa.) This under region widens a little backwards, and narrows again towards 
the end of the perfect floor, That perfect part runs to the middle of the skull, the 
rest is indeed well marked off and hedged in with solid bone, but the floor is merely a 
strong “ aponeurosis,” and not a bony tract right across, as in the large Myrmeco- 
phagide; the naso-palatine canal, however, is quite perfect in this little kind, and 
opens close under the junction of the head and neck. 
The sharp-edged, toothless alveolar region of the maxillary (m.) sends inwards the 
usual flange, and this only leaves a small tract for the higher submesial part ; the two 
tracts are separated by a deepish groove. About three-fifths of the underview of 
the maxillaries is palatine, the rest belongs to the facial walls, which spread out 
on each side of the znferior infraorbital foramina (V*.) into an ear-shaped lobe, and 
then the bone contracts suddenly, and runs inwards to bind on to the middle of the 
side of the rest of the hard palate. This part answers to the socket of the upper 
* wisdom tooth ” in man. 
Fine threads of bone are seen extending backwards into the jugal region from the 
outer lobe of the maxillaries ; these are the starved, abortive jugals (7. ). 
The orbits are less enclosed than ever in this type; in this aspect the inturned 
orbital plate of the frontals (f.), and the antero-inferior cornu of the parietals (p.) can 
be seen, folded over the two pairs of wings of the ‘“sphenoid bone.” The palatine 
hinder third of the hard palate is quite like the part in front of it, and at the line of 
junction of the two palatines, behind, this floor is emarginate, angularly. 
