470 



ANATOMY OF VERTEBRATES. 



slender. The mastoids are compressed and pointed^ and are much 

 less developed than in the Wild Boar, the Masked Boar, or the 

 Babyroussa. The pterygoid fossa? are simple ; not divided into 

 an external and internal compartment, as in the Babyroussa, but 

 they are more extended backward. The sockets of the canines, c, 

 have not the process from the upper part, as in the Sus larvatus. 

 The maxillo-premaxillary suture is early obliterated, except at 

 the apex of the premaxillaries which extend beyond the sockets of 

 the tusks. The nasals, 15, are of great length. The fore part of 

 the lower jaw, fig. 317, is expanded for the sockets of the tusks, c, 

 and truncate, as in Hippopotamus ; but the sockets of the incisors 

 are soon obliterated. In the interior of the skull a tentorial ridge 

 is developed. 



In the Peccary a strong ridge extends from the lower border 

 of the malar. The pterygoids have not the fossae shown in the 

 Babyroussa and Wart-hog, and are less laterally expanded. The 

 paroccipitals rise more to the outside than in Sus. The articular 

 surface for the mandible is concave from before backward. 



In the skull of a Camel (^Camelus bactrianus, fig. 318), the 

 occipital condyles are divided into two surfaces meeting at an 



acute angle, and they 

 come in contact with each 

 other beneath the basi- 

 occipital, Avhich contri- 

 butes an equal share 

 with the exoccipitals to 

 their formation. The 

 paroccipitals are small, 

 and shorter than the 

 mastoids. The occi- 

 pital, II, and parietal, 9, 

 crests are sharp : the 

 zygomatic arches, in relation to the laniariform teeth, .<?, «, o, are 

 longer and overspan a wider temporal fossa, i o, than in true Rumi- 

 nants. The orbit has an entire bony rim. The premaxillaries, ] , do 

 not reach the nasals, 7, and the maxillaries, 2, contribute to form 

 the external bonynostriL In the Llama and Vicugna (^^^c/^e/^^«), 

 the premaxillaries exclude the maxillaries from the nostril. A 

 vacuity between the maxillary, lacrymal, frontal, and nasal re- 

 mams large in Llamas, but is reduced in old Camels to a small 

 size, between the frontal, 8, and maxillary, 2 ; or it may be obli- 

 terated, as is usual in the Vicugna. The antorbltal foramen, h, 

 opens above the last premolar. The orbital plate of the lacrymal 



Skull, Camelus dactrianus. 



