334 



A MEMOIR OX THE EXTINCT 



vancement of the intermaxillaries several lines beyond the alveoli of the central incisors, 

 indicating probably a more prolonged up'per lip than in the animal just mentioned. 



The basilar process, instead of being nearly horizontal and plane, as in the Peccary, 

 ascends obliquely, is carinated inferior!}', and terminates on each side anteriorly in a rela- 

 tively very large, prominent tuberosity, serving as an abutment for the post sphenoidal body. 

 Just in advance of the condyles it is depressed on each side into a deep pit for muscular 

 insertion. The ossa tympanica have the same form and construction as in the Peccary. 

 The guttural region exhibits some of the most remarkable features of the cave head. 



The post-sphenoidal body in the Peccary ascends at a very obtuse angle from the basi- 

 lar process, but in the fossil ascends vertically from the line of the palate, and curves for- 

 ward continuous in the latter direction with the ant-sphenoidal body. The surface of the 

 post-sphenoidal body presents directly forward, and is concave on each side ; and that of 

 the ant-sphenoidal body is directed downwards, and is deeply concave upon each side of 

 the azygous process. Compared to the Peccary, a relatively very deep and capacious 

 fossa with concave sides exists in the fossil between the posterior nares and the post- 

 sphenoidal body. It is divided antero-posteriorly by the middle prominence of the latter 

 and the azygous process of the ant-sphenoidal body. Its sides are constituted by the 

 anterior portion of the roots of the external pterygoid processes dilated or bulging out- 

 wardly, in conjunction with a lateral expansion of the ant-sphenoidal body where it de- 

 scends to form the internal pterygoid process. The communication below is trilobate; the 

 corresponding position in the Peccary being cordiform. 



The ossa palati early unite with the superior maxillary bones as in the Peccary, so that 

 the transverse palate suture is no more visible. In the Peccary the palate bones where 

 they unite rise posteriorly in the form of a deep angular groove to the inferior edge of the 

 nares, but in the- fossil their- palate plates are transversely concave, and form between 

 the extremities of the internal pterygoid processes a sharp crescentic edge, between 

 which and the inferior margin of the nares is a remarkable cul-de-sac, divided into 

 two unequal portions by a vertical partition on the left side of the median line. The 

 space in which this cul-de-sac is situated is eleven lines high from the palatal to the naral 

 margin, and the bottom of the sac extends about one-fourth of an inch anterior to the palatal 



margin 



An enormous cellular dilatation of an oval form apparently protrudes from between the 

 maxillary and palate bones, and extends backwards to the anterior margin of the external 

 pterygoid process. Its interior communicates anteriorly with the cavity of the nose; ex- 

 ternally it is convex, and on its inner surface, forming the lateral parietes of the posterior 

 nares, is concave. It is about two inches long, and at the middle about an inch deep? 

 and three-fourths of an inch wide. It appears to be formed by the palate bone, but cf 

 this I am not sure, as its sutural connexions arc for the most part obliterated. A simi- 

 lar but smaller dilatation exists in Dicotyles labiatus, but in the specimen I have under 

 comparison its sutural connexions are also entirely obliterated. 



One of the most remarkable characters of the cave head is the excessive cellular dilata- 

 tion of the bones about the middle of the fare. In addition to the larger dilatations just 



