DICOTYLIN.fi OF AMERICA. 335 



described, between tlie posterior nares and temporo-maxillary fossa-, the malar hones are 

 very much dilated and cellular; the cells communicating with the interior of the maxillary 

 bones. The latter also are not only very much dilated in advance of the malar bones, but 

 between these and the palate bones above the alveoli they extend backward in a cellular 

 cavity, closed behind by the os unguis, at least an inch from the last molar tooth. 



The foramina at the base of the cranium have the same arrangement and relations as 

 in the Peccary. 



The glenoid cavity is a little more antero-posterior in its long diameter than in the lat- 

 ter, and instead of being upon a level at bottom with the os tympanies is removed from 

 it obliquely downwards and forwards for nearly an inch by the unusual prolongation in 

 this direction of the zygoma. 



The meatus auditorius externus is placed in the same relative position as in the Peccary, 

 and is the extraordinary distance of two and a half inches from the glenoid articulation. 

 The hiatus anterior to the molars is relatively longer than in the Peccary. Its margin 

 is rounded, and out of it rises a linear ridge proceeding to the back of the canine alveolus. 

 Above it, the face exhibits an obtuse low ridge proceeding from just below the infra-orbitar 

 foramen forward, and expanding the whole length of the cresccntic ridge of the canine 

 alveolus, so conspicuous a character in the Peccary. The latter ridge at its upper part 

 turns inwards and forwards to the antero-lateral edge of the nares as formed by the in- 

 termaxillaries and expands gradually downwards and vanishes upon the incisive alveoli. 

 The notch included by the canine alveolar ridge for the reception of the crown of the 

 lower canine when the jaws are closed, is about one and a fourth incites high, and as wide 

 at bottom as the hiatus between the canine and lateral incisor. 



The infra-orbital canal commences immediately above the last molar alveolus. The 

 supra-palatine foramen, as it should be called, instead of spbeno-palatine, because the 

 Bphenoid lmnc docs not always enter into its composition, is placed above and to the 

 inside of the former, is bounded above by the large cellular dilatation of the poste- 

 rior oares, and is continuous upwards and outwards with the fissure between the latter 

 and the BUperior maxillary and lachrymal bones. The posterior palatine canal commences 

 at the bottom of a vertical fissure passing from the last designated foramen downwards 

 between the vertical plate of the palate bone and the tuberosity produced by the last molar 

 alveolus. Its exit upon the surface of the hard palate is near the middh; of the hiatus an- 

 terior to the molars, a couple of lines within its margin, and is continuous with a groove 

 advancing to the naso-palatine foramina, as in the Peccary. 



Tin- relative position of the molars, canines, and incisors, is the same as in the latter. 

 Tin' true molars of the recent Peccary (PI. 37, figs. 1-1,) appear to be constructed on 

 the type of the Hog, whereas in the cu\c head they partake more of the character of the 

 Hippopotamus. In the former the crowns present two pairs of principal, short, conoidal, 

 wrinkled tubercles, with constituent portions of the basal ridge wrinkled and tuberculate. 

 The la.-t lower molar, as in all Pachyderms, has its additional lobe. In the latter the 

 principal loin-- are relatively very long, prismoid, not wrinkled, but constricted at the -id, -. 

 and oppnsr.lt. i another as in the 1 lippopotamus, so that when the summits are worn <ll'. 



vol. x — no 



