104 MR. W. kK. PARKER ON THE STRUCTURE AND 
therefore must add it to the list of characters in which this type comes nearer to the 
normal Mammal than its congeners. 
The upper view of the cranium (Plate 14, fig. 2) shows, in front, the remarkable 
form of the snout, the roof of which suddenly pinches in, in front, after dilating as 
suddenly on emerging from beneath the nasal bones (v.). The roof (al.n.) ends in 
front, like the nib of a pen, and the sides are swollen, and then scooped away in a 
crescentic manner, making the nostrils look forward. Close beneath this expanded 
front lies the root of the curious long twisted narial valve (n.v., fig. 3) which projects 
in front, right and left of the contracted fore end of the snout. 
The difference between the general outline of this skull, and that of a nearly ripe 
Tatusia hybrida, is considerable ; moreover, although larger relatively at the time of 
birth, it is not nearly so much developed (compare Plate 14 with Plate 6). 
The Edentate diminution of the jaws is much less than in the Tatou; indeed, the 
skull is fairly intermediate between the skull of that kind of Armadillo and that of a 
large and important Insectivore from the East Coast of Africa, namely, Rhyncoeyon— 
a type to be described in my next paper. 
In both these nearly mature embryos the basifacial length is twice that of the 
basicranial, the point taken being that where the vertical ethmoidal and the 
presphenoidal regions meet. But the Aard-Vark’s head is much the longer and 
narrower of the two—more like that of an Anteater, in this respect, and yet more 
like the skull of an Insectivore than that of any of the Myrmecophagide. Looking 
at the main roof bones the nasals are now only one-tenth shorter than the frontals 
and are one-tenth longer than the parietals (n., f, p.). This is a very different propor- 
tion to what we see in Zutusia, and yet the general form is very similar, for the 
frontals have to swell and broaden over huge ethmoidal masses in both cases (Plate 15, 
figs. 1,2; and Plate 5, fig. 1). Thus, in both cases, the antorbital and postorbital 
regions are of equal breadth, except in so far as the latter is widened by the 
squamosals in the glenoid region. The general frontal convexity seen in Tutusia 
(Plate 6, fig. 2), and still more in Dusypus (Plate 7, fig. 2), is exchanged in Orycteropus 
for a considerable median hollowing of the roof, which affects even the hinder part of 
the nasal bones. So that, as we shall see in the next figure (3), there is a very 
peculiar “ beetling” of the brow in this type, the convexity of the frontals being only 
lateral and not general. But the skull rises well in the coronal region ; yet there, at 
present, it is unfinished, a large diamond-shaped fontanelle ( fo.) still persisting. Here 
we gain that which the Armadillos are deficient in, namely, a good postorbital process 
to the frontal bone, as the end of a good, clean, well arched supraorbital rim. That 
ridge and process is very short and abortive even in the Unau (Plate 9), which has 
also some suprafrontal hollowing, but in Cycloturus, Tutusia, Dasypus, and Manis, all 
this is absent.* 
* We shall see this Bchidnine feebleness of the skull in many of the Insectivora, also, so that this 
imperfection of the orbit must not be taken as a necessary correlate of the suppression or abortive 
