THE SKELETON IN MAMMALIA. PECTORAL GIRDLE. 493 



FIG. 101. SKELETON OF A CAPE BUFFALO (Bubalus coffer). 

 The left scapula is omitted for the sake of clearness x T y. (Brit. Mus.) 



1. premaxilla. 7. femur. 



2. nasal. 8. patella. 



3. orbit. 9. tibia. 



4. neural spine of first thoracic 10. metatarsals. 



vertebra. 11. radius. 



5. scapula. 12. metacarpals. 



6. rib. 



In the RODENTIA there are generally thirteen pairs of ribs, 

 which do not present any marked peculiarities. 



The CARNIVORA have thirteen to fifteen pairs of ribs, 

 whose vertebral portions are slender, nearly straight and 

 subcylindrical, while their sternal portions are long and 

 imperfectly ossified (fig. 76, 5). There is nothing that calls 

 for special remark about the ribs, in either INSECTIVOKA or 

 CHIROPTERA. 



PRIMATES. In Man and the Orang (Simia) there are ge- 

 nerally twelve pairs of ribs ; in the Gorilla and Chimpanzee 

 (Antkropopithecus), and Gibbons (Hylobates), there are thirteen, 

 in the Cebidae twelve to fifteen, and in the Lemuroidea twelve 

 to seventeen pairs. The first vertebral rib is shorter than the 

 others, and the sternal ribs generally remain cartilaginous 

 throughout life, though in man the first may ossify. 



APPENDICULAR SKELETON. 



THE PECTORAL GIRDLE. 



By far the most primitive type of the pectoral or shoulder 

 girdle is found in the MONOTREMATA. The scapula (fig. 102, 

 A, 1) is long and recurved, and has only two surfaces, one 

 corresponding to the prescapular 1 fossa, the other to the post- 

 scapular 1 and subscapular 1 fossae. The coracoid is a short bone 

 attached above to the scapula and below to the presternum ; 

 it forms a large part of the glenoid cavity. In front of the 

 coracoid there is a fairly large flattened epicoracoid (fig. 102, 6); 



1 See p. 405. 



