352 



THE BOOK OF THE CAT. 



canine, are three premolars PM. These are 

 the second or permanent series, and succeed 

 the kitten's milk-teeth. The first one is very 

 small, and has only a single cusp ; the second 

 , is .larger, and has two usps ; the third is the 

 largest, and is sometimes called the " sec- 

 torial " tooth. It has three pointed cusps and 

 three fangs, or roots. Immediately behind it, 

 and placed somewhat transversely, is the 

 single true molar. It is a small tooth, of 



The Axial Skeleton (see p. ^354) consists of 

 the bones forming the neck, thorax, loins, and 

 tail. The neck is relatively short, and con- 

 sists of seven bones a number almost con- 

 stant throughout the animal kingdom, the 

 giraffe, the hippopotamus, and the whale 

 having the same number. Succeeding these 

 are the dorsal, or thoracic, vertebrae (thirteen 

 in number), each one supporting two ribs one 

 on each side. Then follow the seven vertebras 



B. 



FIG. III. SUPERFICIAL FLEXOR 



TENDONS OF THE CAT'S 



LEFT FORE-FOOT 



A, Perforatus, or flexor sub- 



digitorum ; B, Perforans, or 



flexor profitndus digitorutn. 



FIG. IV. BONES AND PRINCIPAL LIGA- 

 MENTS OF A CAT'S TOE, SHOWING 

 MECHANISM OF RETRACTILE CLAW. 

 A, Distal or terminal phalanx; B, Middle; 

 c, Proximal ; D, Perforatus tendon ; E, Per- 

 forans tendon ; F, Elastic ligament. 



IT. 



FIG. V. PADS OF CAT S 

 LEFT FORE-FOOT. 



A, Plantar pad ; B, Digital pad ; 

 c, Pisiform pad. 



obtuse form, and indefinitely cusped ; it has 

 no predecessor in the kitten's milk set. 



In the lower jaw, immediately after the 

 canine tooth, there are only two premolars 

 (PM. PM'.) in the permanent set which have 

 predecessors, the last tooth (M.) being the only 

 true molar, and having no predecessor in the 

 milk set. Occasionally, in the lower jaw there 

 is a small premolar corresponding to the first 

 premolar of the upper jaw. In the kitten 

 from about six or seven weeks to about five 

 months old, there are only twenty-six teeth, 

 the number and form being very similar to 

 the adult set. The two permanent molars in 

 the upper and lower jaw are absent. 



composing the lumbar region. They are stout, 

 thick bones, with long, transverse processes 

 for the attachment of certain muscles sup- 

 porting the body cavity, etc. No ribs are 

 attached to these bones. Immediately behind 

 are three smaller bones forming the sacrum, to 

 which the pelvis, or hip-bones, are articulated. 

 The terminal bones of the axial skeleton are 

 the tail, or caudal, and vary from nineteen to 

 twenty-one. 



The Ribs (thirteen on each side) are ex- 

 tremely light, elastic, and slender. Nine of 

 these on each side join the sternum or breast- 

 bone directly, and are called true ribs ; the re- 

 mainder are free, and terminate in cartilaginous 



