Xll. 



with the occipital region of the cranium ; these vertebrae con 

 stitute the framework of the neck, and in all known recent 

 Mammals, except three the Manatee (Manatus australis), the 

 Two-toed Sloth ( Choloepus hojfmanni) with six, and the Three-toed 

 Sloth fBradypus tridactylusj with nine consists of seven distinct 

 bones, which, however, are in the case of several genera, notably 

 belonging to the Cetacea, in a greater or less number ankylosed 

 together so as to form a solid mass. The second cervical vertebra 

 is termed the axis, and, except in certain CETACEANS, always de- 

 velops a well denned odontoid process. 



Dorsal, or Thoracic. Behind these lie the dorsal, or, since to 

 its vertebrae only are articulated the movable ribs which form 

 the arch of the thorax, as it would be more correct to term it, 

 thoracic region; the anterior rib is attached below to the sternum 

 (vide infra), as are also usually several of those which follow. 



Lumbar. The lumbar region consists of those vertebrae in 

 front of the sacrum which bear no movable ribs. The number of 

 vertebrae in the conjoined thoracic and lumbar regions is tolerably 

 constant in any given group of animals, any increase of the one 

 being at the expense of the other ; the smallest number of 

 thoracico-lumbar vertebrae occurs in the Armadillos ( Dasypodidm) 

 which have only fourteen, while the greatest number is found in 

 the Hyrax or Rock-Babbit, the supposed Cony of the Scriptures, 

 in which no less than thirty are present ; in Man, the higher 

 Apes, and most Bats, the number is seventeen ; in nearly all 

 Marsupials, nineteen. 



Sacral, The sacral region is that which is situated between 

 the lumbar and caudal regions ; in it the vertebrae are ankylosed 

 together so as to form a single mass ; the number of vertebrae 

 included in the sacrum is variable, even in different individuals 

 belonging to the same species, especially as age advances, when 

 certain of the caudal vertebras become incorporated with those of 

 the true sacrum. These bones are absent in the CETACEA. 



Caudal. The caudal vertebrae are those placed behind the 

 sacrum, and terminate the vertebral column. They naturally vary 

 greatly in number, there being usually four only in Man, and those 

 rudimentary, whereas in the West African Long-tailed Pangolin 

 (Manis longicaudata) there are as many as forty-six. They are 

 also, for obvious reasons, numerous and highly developed in the 

 Macropodidce and the CETACEA. 



Chevron Bones. To the under-surface of the caudal vertebrae 

 of many Mammals, in which the tail is well developed, are 

 attached by articulation small bones, of the shape of an inverted 

 arch, which have received the name of " chevron bones" 



Sternum. The mammalian breast-bone (sternum) is a bone, or 

 series of bones, placed longitudinally in the mesial line, on the 

 inferior aspect of the thorax, and connected with the vertebral 

 column by a series of more or less ossified ribs. It is divided 



