448 DIGESTIVE SYSTEM OF THE OX 



each side of the glosso-epiglottic fold. The muscles are well developed, and re- 

 semble in general those of the horse; the hyo-glossus arises by additional portions 

 from the great and middle cornua of the hyoid bone. The tongue is highly pro- 

 tractile and is the chief organ of prehesion. 



THE TEETH 1 



The formula of the permanent teeth of the ox is: 



/ 3 3\ 



2 I I - C - P - jNI - I = 32 



/ 3 3\ 



(I-C-P-jM-) = 

 V 4 3 3/ 



The incisors are absent from the upper jaw. There are eight incisors in the 

 lower jaw, arranged in a somewhat fan-like manner. They are simple teeth, 

 without infundibulum. The crown is white, short, and shovel-shaped. The root 

 is rounded, and is embedded in the jaw in such a manner as to allow a small amount 

 of movement. There is a distinct neck. In addition to the simple numerical 

 designation, the following terms are commonly applied to the individual teeth: 



Fig. 3S3. — Incisor Teeth of Ox; Lingual Aspect. 

 C. s., Caruncula sublingualis. 



central, first intermediate, second intermediate, and corner incisors. It is probable 

 that the latter are much modified canines. The incisors of the adult ox do not 

 •undergo continued eruption, as is the case in the horse; in old age, however, the 

 gum retracts so that the roots are partly exposed and may come into wear.^ The 

 deciduous incisors : differ from the permanent set chiefly in being much smaUer. 

 The crowns are narrower and diverge more. 



The canines are absent (unless the fourth incisors be considered to represent 

 them in the lower jaw). ^ 



The cheek teeth (Figs. 134, 384) resemble those of the horse in number and 

 general arrangement. They are, however, smaller, and also differ in the fact that 

 they progressively increase in size from before backward. This feature is so marked 

 that the first tooth is quite small, and the space occupied by the first three (i. e., 

 the premolars) is only about one-half of that required for the posterior three (i. e., 

 the molars). The enamel folds stand out even more prominently in relief on the 

 masticatory surface than in the horse. The occurrence of wolf-teeth is rare. 



' Other figures which show the teeth are to be found in the description of the skull. 



2 The reader will note here the difference between the structure and behavior of the bracny- 

 dont (short-crowned) incisors of the ox and the hypsodont (long-crowned) type of the horse. 



' According to A. Hoffman, the anlagen of the upper canines are present in the foetus, but- 

 soon disappear. 



