324 



j\IE. W. K. PAEKER ON THE STEUCTXJEE 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 

 Euminant 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 XXXVII. fig. 1, n.) 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 {px.), and for a less extent with the maxillary [mx.) ; 

 they terminate in a transverse line half an inch behind their maxillary suture. The 

 frontals (/'.) 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 XXXVII. 

 fig. 1) which is bounded behind above by the short arrested postorbital process, and 

 lower down and within by the orbito-sphenoid {o.s.). The upper surface of the parietals 

 {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 {t.f.) ; and behind they are somewhat 

 impinged upon by the large superoccipital wall [s.o.). 



The premaxillaries (Plate XXXVI. fig. 4, and Plate XXXVII. fig. l,;px.) have a 

 large facial and a lesser palatine region, the palatine spurs {p.px.) being slender and com- 

 pressed. The huge maxillary [mx.), besides forming most of the fore face and the anterior 

 root of the zygoma, by its last tooth-socket (a large pupiform cavity), binds behind upon the 

 external pterygoid plate and descending extremity of the palatine (Plate XXXVII. fig. 1, 

 mx.^pa^e.pg.). Below (see Plate XXXVI. fig. 4, mx. ) 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 XXXVl. fig. 4) is two thirds the length of the skull and face. The 

 palatine bones (!-'«.) 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. This latter bone, the " pterygoid " proper (pg.), is 

 very thin in its ascending part ; and on the riglit side the uppermost squamous part is 

 a separate piece, the mesopterygoid (Plate XXXVI. fig. 4, ms.jyg.), a bone not commonly 

 distinct in the Mammalia ; yet in my collection it occurs in the Fox [Canis vulpes), 

 and is subdistinct in tlie Hedgehog {Erinaceus ciiroptvus); here, in the Pig, it is a small 

 triangular scale. The inferior part of the pterygoid is thicker and is subfalcate, the 



