Zoological Society. 293 



cited Bovidce have been supposed to differ actually in the number of 

 their vertebrae, whereas this is absolutely the same in each of them ; 

 after the seven cervical vertebrae there are nineteen true vertebrae, 

 i. e. nineteen vertebrae between the last cervical and the sacral ver- 

 tebrae. In the embryos of many Ungulates, rudiments of ribs (pleur- 

 apophyses) are found moveably attached to vertebrae, to which they 

 afterwards become anchylosed, and accordingly are called lumbar 

 vertebrae. In the Aurochs these elements retain their freedom and 

 growth in one more vertebra than in the common Ox ; in the Bison 

 two more vertebrae have moveable pleurapophyses. Accordingly we 

 find that if the common Ox has but thirteen dorsal vertebrae, it has 

 six lumbar vertebrae ; if the Aurochs has fourteen dorsal, it has five 

 lumbar ; and if the Bison has fifteen dorsal vertebrae, it has but four 

 lumbar. But the unity of the numerical character of the true ver- 

 tebrae does not stop here ; for when we find, e. g. in the Dromedary, 

 the Camel, the Llama, and the Vicugna, only twelve dorsal vertebrae, 

 the typical nineteen is completed by seven lumbar vertebrae ; and 

 this number is never surpassed in the Ruminants. Most of the species 

 agree with the common Ox in the number of the true vertebrae that 

 retain their pleurapophyses in moveable connection. The Reindeer 

 and the Giraffe resemble the Aurochs in having fourteen dorsal ver- 

 tebrae. But what perhaps is still more interesting and usefully in- 

 structive as to the true affinities of the hoofed quadrupeds with toes 

 in even number, is the fact, that besides their common possession of 

 a complex stomach and simple caecum, of a peculiar form of astra- 

 galus, of a femur with two trochanters, and of a symmetrical pattern 

 of the grinding surface of the molar teeth, they also agree, as I have 

 shown in my paper on the genus Hyopotamus, in having nineteen 

 natural segments of the skeleton, neither more nor less, between the 

 neck and the pelvis. The Babiroussa, the African Wart-hogs (Pha- 

 cochcerus), and the extinct Anoplotherium, resemble the majority of 

 Ruminants in having thirteen dorsals and six lumbars ; the Wild Boar 

 and the Peccari resemble the Aurochs in having fourteen dorsals and 

 five lumbars ; the Hippopotamus resembles the Bison in having fifteen 

 dorsals and four lumbars. 



This constancy in the number of the true vertebrae in the Artio- 

 dactyle Ungulates is the more remarkable, and demonstrative of their 

 natural co-affinity, by contrast with the variable number of those 

 vertebrae in the odd- toed or Perissodactyle group, in which we find 

 twenty-two dorso-lumbar vertebrae in the Rhinoceros, twenty-three 

 in the Tapir and Palaeotherium, and as many as twenty-nine in the 

 little Hyrax. 



With regard to the vertebrae of the trunk of the Aurochs, I may 

 remark, that the only accessory process in addition to the ordinary 

 zygapophyses and diapophyses is the metapophysis, which appears 

 as a stout tubercle above the diapophysis in the middle dorsals, and 

 gradually advances and rises upon the anterior zygapophyses in the 

 posterior dorsal and lumbar vertebrae. This process is developed to 

 an equality of length with the spinous processes in the Armadillos. 



