629 



If the foregoing osteological specimens from the hoofed animals with the digits in even number be 

 compared together, they will be found, notwithstanding the difference of form, proportion and size pre- 

 sented by the Hippopotamus, Wild Boar, Vicugna and Chevrotain, to agree in the following points, 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 even-toed or ' artiodactyle ' Ungulates, the dorso-lumbar verte- 

 brae are the same in number, as a general rule, in all the species, being nineteen. The rare exceptions 

 appear to be due to the development, rarely to the suppression, of an accessory vertebra as an individual 

 variety, the number in such cases not exceeding twenty or falling below eighteen, and the supernumerary 

 vertebra being most usually manifested in the domesticated and highly-fed breeds of the common Hog. 

 The recognition of this important character appears to have been impeded by the variable number of 

 moveable ribs in different species of the Artiodactyles, the dorsal vertebrae, which these ribs characterize, 

 being fifteen in the Hippopotamus and twelve in the Camel : and the value of this distinction has been 

 exaggerated owing to the common conception of the ribs as special bones, distinct from the vertebrae, 

 and their non-recognition as parts of a vertebra equivalent to the neurapophyses and other autogenous 

 elements. The discovery of the pleurapophyses under the condition of rudimental ribs attached to the 

 ends of the lumbar diapophyses in the Wombat (No. 1792), the foetal Pig and some other quadrupeds, 

 which afterwards become suturally attached or anchylosed, and the pleurapophysial nature of a part of 

 the so-called perforated transverse process of the cervical vertebra, as exemplified in Nos. 23 and 33, 

 show that the anthropotomical definition of a dorsal vertebra, as one that supports ribs, is inapplicable 

 to the Mammalia generally, and is essentially incorrect. It is convenient, in comparative tables of 

 vertebral formulae, to denote the number of those vertebrae of the trunk in which the pleurapophyses 

 remain free and moveable, constituting the 'ribs' of Anthropotomy ; but the differences sometimes 

 occurring in this respect, in individuals of the same species, have their unimportance manifested when 

 the true nature of a rib is recognized. The vertebral formulae of the Artiodactyle skeletons above 

 described show that the difference in the number of the so-called dorsal and lumbar vertebrae does not 

 affect the number of the entire dorso-lumbar series : thus the Indian Wild Boar (No. 3248) has d 13, 

 I 6,= 19 ; the Domestic Hog (No. 3266) and the Peccari (No. 3380) have d 14, 1 5,= 19 ; the Hippo- 

 potamus (No. 3404) has d 15, / 4,= 19 ; the Gnu (No. 3808) and Aurochs (No. 3819) have d 14, / 5, 

 = 19 ; the Ox (No. 3825) and most of the true Ruminants have d 13, I 6,= 19 ; the aberrant Rumi- 

 nants (Nos. 3445, 3482 & 3489) have d 12, I 7,= 19 : these facts illustrate the natural character and 

 true affinities of the Artiodactyle group. They are further illustrated by the absence of the third tro- 

 chanter in the femur, and by the place of perforation of the medullary artery at the fore and upper part 

 of the shaft, as in the Hippopotamus, the Hog, and most of the Ruminants. The fore part of the astra- 

 galus is divided into two equal or subequal facets : the os magnum does not exceed, or is less than, the 

 unciforme in size, in the carpus ; and the ectocuneiform is less, or not larger, than the cuboid, in the 

 tarsus. The digit answering to the third in the pentadactyle foot is unsymmetrical, and forms, with 

 that answering to the fourth, a symmetrical pair. If the species be horned, the horns form one pair 

 or two pairs ; they are never developed singly and symmetrically from the median line. The post- 

 tympanic does not project downward distinctly from the mastoid, nor supersedes it in any Artio- 

 dactyle ; and the paroccipital always exceeds both in length. The bony palate extends further back 

 than in the Perissodactyles ; the hinder aperture of the nasal passages is more vertical and com- 

 mences posterior to the last molar tooth. The base of the pterygoid process is not perforated by the 

 ectocarotid artery. The crowns of the premolars are smaller and less complex than those of the true 

 molars, usually representing half of such crown. The last milk-molar is trilobed. 



