Royal Society. 251 



transference of their articular surfaces upon the metapophyses, which 

 are processes distinctly superadded. 



lu the Rodent Order, the modifications of the metapophyses and 

 anapophyses are described in the common and Malabar Squirrels, 

 the JNIarmot, the Hydromys, the Rat, the Cape Jerboa, in which the 

 anapophyses attain their maximum of relative size ; in the Beaver, 

 the Porcupine, the Coypu, the Paca, the Capybara, and in the Hare. 

 The distinction between the metapophyses and the pre-zygapophyses 

 is particularly strongly marked in the Capybara. 



In the Insectivora, the Hedgehog is an instance in which metapo- 

 physes are developed but not anapophyses. The modifications of 

 both processes are traced, in the Marsupial Order, in the Thylacine, 

 the Dasyure, the Wombat, the Perameles, and in two species of 

 Kangaroo. The diapophyses being developed from the last as well 

 as the antecedent dorsals in these marsupials, renders the homology 

 of the transverse processes of the lumbar vertebrae unmistakeable : 

 but the diapophyses of those vertebrae are lengthened out by anchy- 

 losed pleurapophyses, of which those of the first lumbar vertebra in 

 the Wombat, compared by the author, had not completely coalesced. 

 In the Ornithorhynchus paradoxus the metapophyses are double in 

 some of the anterior dorsal vertebras, but become single in the sixth 

 dorsal, and gradually increase to the twelfth. The anapophyses are 

 rudimental. 



In the Ruminant Order, the accessory processes are described in 

 the Elk, the Giraffe, the Gnu, the Equine Antilope, the Ox, the 

 Aurochs, the Camel, the Vicugna, the Memmina, and the Musk-deer. 

 The anapophyses are rarely, and then only very feebly developed ; 

 the metapophyses are constant; they appear as tubercles above the 

 diapophyses in the anterior and middle dorsals, and pass upon the 

 zygapophyses in the penultimate or last dorsal. The author records 

 a peculiarity in the skeleton of a musk-deer {^Moschns moschiferus). 

 In the pair of ribs attached to the thirteenth dorsal vertebra the 

 tubercle is wanting, and the diapophysis is obsolete, as in the last 

 dorsal vertebra of other Moschidcc; but in the following vertebra, 

 answering to the first lumbar in other Moschidcc, the rib is developed 

 with a head and a distinct tubercle, articulated to an equally distinct 

 diapophysis. This plainly demonstrates the homology of the diapo- 

 physis in the next vertebra, answering to the second lumbar in 

 other 3Ioschidce. 



There are no anapophyses in the Hog-tribe and Hippopotamus : 

 the metapophyses resemble those of the ruminant artiodactyles. 

 The perissodactyle Ungulates manifest some peculiarities. In the 

 Sumatran Tapir, e. g. the metapophysis is a very distinct process in 

 the third dorsal, subsides in the four next dorsals, and reappears as 

 a prominent process in those that follow, but does not attain the 

 position upon the zygapophysis except in the last lumbar vertebras, 

 [n the Horse and lihinoceros, as well as the Tapir, although there 

 are no proper anajmphyses, the diapophysis of the last lumbar de- 

 velopes an articular surface on its back part which articulates with 

 a corresponding surface on the sacrum. In the vertebrae of the 



