THE SKELETAL SYSTEM 



213 



In reptiles, ribs increase in number, and in some forms encircle the 

 abdominal cavity. Abdominal ribs are common. The ribs of snakes are 



PHALANGES 



METACARPALS 



MANDIBLE. 



/CLAVICLE. 



ACROMION PROCESS. 



-CORACOID. 



-MANUBRIUM. 

 STERNUM. 

 XIPHOID PROCESS. 



^-CARPALS. 



PHALANGES. 



Fig. 170.— Human skeleton viewed from in front. (Reproduced in modified form 

 from "The Human Body" by Dr. Logan Clendening, (Copyright 1927, 1930 by Alfred 

 A. Knopf, Inc.) by permission of and special arrangement with Alfred A. Knopf, Inc., 

 authorized publishers.) 



especially numerous. In mammals and man, ribs which articulate with 

 the vertebrae and extend around the body cavity are limited to the thoracic 

 region. 



