542 



If the foregoing osteological specimens from the hoofed animals with the hind digits in uneven number 

 be compared together, they will be found to present, notwithstanding the differences of form, proportion 

 and size presented by the Rhinoceros, Hyrax, Tapir and Horse, the following points of agreement, 

 which are the more significative of natural affinity when contrasted with the skeletons of the hoofed 

 animals with digits in even number. Thus, in the odd-toed or ' perissodactyle ' Ungulates, the dorso- 

 lumbar vertebrae differ in different species, but are never fewer than twenty-two : the femur has a third 

 trochanter, and the medullary artery does not penetrate the fore part of its shaft. The fore part of 

 the astragalus is divided into two very unequal facets. The os magnum and the digitus medius which 

 it supports is large, in some disproportionately, and the digit is symmetrical : the same applies to the 

 ectocuneiform and the digit it supports in the hind foot. If the species be horned, the horn is single; or 

 if there be two, they are placed on the median line of the head, one behind the other, each being thus 

 a single or odd horn. There is a well-developed post-tympanic process, which is separated by the true 

 mastoid from the paroccipital in the Horse, but unites with the lower part of the paroccipital in the 

 Tapir, and seems to take the place of the mastoid in the Rhinoceros and Hyrax. The hinder half, or a 

 larger proportion, of the palatines enters into the formation of the posterior nares, the oblique aperture 

 of which commences in advance of the last molar, and in most, of the penultimate one. The ptery- 

 goid process has a broad and thick base and is perforated lengthwise by the ectocarotid. The crowns 

 of the antepenultimate as well as of the penultimate and last premolars are as complex as those of the 

 molars : that of the last lower milk-molar is bilobed. To these osteological and dental characters may 

 be added some important modifications of internal structure, as e. g. the simple form of the stomach 

 and the capacious and sacculated caecum, equally indicating the mutual affinities of the odd-toed or 

 perissodactyle hoofed quadrupeds, and their claims to be regarded as a natural group of the Ungulata. 

 Many extinct genera, e. g. Lophiodon, Tapirotherium, Palceotherium, Hippotherium, Acerotherium, 

 Macrauchenia, Elasmotherium, Coryphodon, have been discovered, which once linked together the now 

 broken series of Perissodactyla, represented by the existing genera Rhinoceros, Hyrax, Tapirus, and 

 Eguus. 



Order ARTIODACTYLA 

 (Pachydermes d doigts paires et Ruminans, Cuv.). 



Suborder NON-RUMINANTIA. 



Family Suidee (Hogs, Wart-hogs, Peccaris). 



Genus Sits. 



Dental formula :_ g, c j p g, * g =44. 

 3248. The skeleton of an Indian Wild Boar (Sus Scrofa). 



The vertebral formula is : 7 cervical, 13 dorsal, 6 lumbar, 4 sacral, and 23 caudal (one or 

 two may be wanting at the end of the tail). The fifth and sixth cervical vertebrae are remark- 

 able for the great expanse of the lameUiform, overlapping, and downwardly directed costal 



