INTRODUCTION. 6 



but, in man, the last-named are followed by five 

 vertebrse immovably united together to make up the 

 sacru/m, and these again by tail- or caudal vertebrae. 

 Man has four such vertebrse, all poorly developed, and 

 fused with one another (Fig. 2, 5); but in many 

 animals there are a large number, movably united 

 to make up a taU. 



The ribs, which in mammals bound the chest, are 

 jointed to the thoracic vertebrse. Man has 12 

 pairs of ribs ; each rib consists of a bony part behind 

 and a gristly (cartilaginous) part in front. The so- 

 called true ribs (Fig. 2, 14) [the upper pairs] are 

 movably united with the breast-bone, but this is not 

 the case with the false ribs (Fig. 2, 15). 



In the head we distinguish the brain-case or 

 cranium, and the skeleton of the face. The first 

 contains the cranial cavity in which the brain is 

 enclosed. We distinguish — 2 frontal bones (fused to- 

 gether in man. Fig. 2, 6) ; 2 parietal bones (7) ; 2 

 temporal bones (8) ; an occipital bone (9) composed 

 of several pieces fused together, perforated by the 

 foramen magnum [where brain and spinal cord unite], 

 and bearing two elevations or condyles [for efiecting 

 union with the backbone] ; and the sphenoid and 

 ethmoid bones which make up the base of the cranium. 

 The facial skeleton consists of the framework of the 

 jaws and palate, and, together with some of the 

 cranial bones, bounds the cavities in which the eyes 

 are contained (orbits), and the nasal cavities. It 

 consists of the maxiUary bones (Fig. 2, 12), the pre- 

 maxiUary bones (Fig. 3, 7, — in man these 4 bones are 

 fused together into one piece), the nasal bones, the 

 lachrymal bones, the ploughshare bone (vomer), the 

 turbinated bones, the cheek-bones (or malars. Fig. 

 2, 11), the palate-bones, and the lower jaw (Fig. 2, 13). 

 (The last originally consists of two symmetrical halves.) 



The upper and lower limbs are built on the same 

 type, and therefore consist of corresponding parts 



