CHARACTEKS OF EVEN"-TOED BEASTS. 181 



tlieir non-recognition as parts of 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 dia- 

 pophyses, 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, 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 form- 

 ula, to denote the number of those vertebrae of the trunk 

 in which the pleurapophyses remain free and movable, con- 

 stituting 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 form- 

 ulae of the artiodactyle skeletons show that the difference 

 in the number of the so-called dorsal and lumbar verte- 

 bras does not affect the number of the entire dorso-lumbar 

 series : thus, the Indian wild boar has c?, 13, ?, 6 = 19 ; 

 i. e. 13 dorsal, and 6 lumbar, making a total of 19 trunk- 

 vertebra; the domestic hog and the peccari have c/, 14, 

 /, 5, = 19; the hippopotamus has cZ, 15, /, 4, = 19 ; the gnu 

 and aurochs have c?, 14, /, 5, = 19; the ox, and most of 

 the true ruminants, have c/, 13, /, 6, = 19 ; the camel and 

 lamas have cZ, 12, Z, 7, = 19. These facts illustrate the 

 natural character and true affinities of the artiodactyle 

 group. They are further shown by the absence of the 

 third trochanter in the femur, and by the place of perfo- 

 ration 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 astragalus is di- 

 16 



