524 MR. W. K. PARKER ON THE STRUCTURE AND 
is an irregular pyramid, with two equal and two unequal sides and an oblique base. 
A complete contrast in outward form to the human skull, that of the Pig is straightest 
of all the types; it is very angular and strongly built, but its bone-tissue is inferior in 
density to that of the Sheep, being intermediate in this respect between the bone of a 
tuminant and that of a Cetacean. The flat top of the skull, with its orbits flush with 
the top, indicate the semiaquatic habits of its owner; and the immense depth and 
squareness of the base of the pyramid is correlative to the high neck and strong 
shoulders of this type: leverage is suggested by every ridge and every snag. Coming 
back to the morphology of the matter, I may remark that the long straight nasals 
(Plate XX XVII. fig. 1, 7.) overlap the snout in front, and only show their edge in the 
side view. ‘They are articulated by suture along their outer edge with the upper edge 
of the long premaxillary wedge (pa.), and for a less extent with the maxillary (mw.) ; 
they terminate in a transverse line half an inch behind their mazil/ary suture. 'The 
frontals (f.) together form a somewhat pentagonal plate, divided along the mid line by . 
the sagittal suture. The anterior third is deeply grooved, the grooves issuing from the 
“infraorbital foramen ;” the posterior half of their outer margin is thick, and some- 
what raised as the superorbital ridge. There is a large orbital plate (Plate XXXVIL 
fig. 1) which is bounded behind above by the short arrested postorbital process, and 
lower down and within by the orbito-sphenoid (0.s.). The upper surface of the parictals 
(p.) is of short extent, and divided by the continuation of the sagittal suture ; they are 
greatly pinched in to form the large temporal fossa (¢.f.); and behind they are somewhat 
impinged upon by the large superoccipital wall (s.0.). 
The premaxillaries (Plate XXXVI. fig. 4, and Plate XXXVII. fig. 1, pa.) have a 
large facial and a lesser palatine region, the palatine spurs ( p.pa.) being slender and com- 
pressed. The huge maxillary (i2.), besides forming most of the fore face and the anterior 
root of the zygoma, byits last tooth-socket (a large pupiform cavity), binds behind upon the 
external pterygoid plate and descending extremity of the palatine (Plate XXXVIL. fig. 1, 
m&.,pa.,e.py.). Below (see Plate XXXVI. fig. 4, me.) it forms three fourths of the elegant 
grooved and ribbed hard palate; the double “posterior palatine foramen” (p.p,f-) 
is partly in this bone and partly in the palatine. The median suture of the hard 
palate (Plate XXXVI. fig. 4) is two thirds the length of the skull and face. The 
palatine bones (pw.) by their primary ascending plate articulate with the vomer, and 
send forwards a long scoop-like process beneath the lateral ethmoids. After forming 
the elegant end of the hard palate they grow downwards as a thick boss, which articu- 
lates with the maxillary and external pterygoid process on the outside, and with the 
internal pterygoid plate on the inside. ‘Chis latter bone, the “ pterygoid” proper (pq.), is 
very thin in its ascending part; and on the right side the uppermost squamous part is 
a separate piecc, the mesopterygoid (Plate XXXVL. fig. 4, ms.pg.), a bone not commonly 
distinct in the Mammalia; yet in my collection it occurs in the Fox (Canis vulpes), 
and is subdistinct in the Hedgehog (Lrinaceus cwropeus); here, in the Pig, it is a small 
triangular scale. ‘The inferior part of the pterygoid is thicker and is subfalcate, the 
