DIGESTIVE SYSTEM OF THE SHEEP 



471 



narrow depressions in the form of a V and separated by the central papilla incisiva 



at the deep anterior ends of which the incisive or naso-palatine ducts open. The 



ridges of the palate, some fourteen in numljer, are irregular and their edges are 



smooth; most of them alternate with those of the 



opposite side, from which they are separated by the 



median raphe palati. The posterior third or rather 



more is not ridged and presents numerous orifices of 



ducts of the palatine glands. The mucous membrane 



is often more or less pigmented. The soft palate 



resembles that of the ox. 



The mucous membrane of the cheeks is covered 

 with large papillae, many of which are long and sharp- 

 pointed, while others are short and blunt. There is 

 also a series of conical papillae on the floor of the 

 mouth, under the lateral part of the tongue. 



The tongue resembles that of the ox in form, but 

 the tip is comparatively smooth; the papillaj here are 

 very numerous, but short and blunt. This difference 

 is in conformity with the dissimilarity in the mode of 

 prehension of the two species. The prominence of 

 the dorsum is commonly not so pronounced nor so 

 sharply marked off in front as in the ox. The root- 

 is smooth. The mucous membrane of the dorsum is 

 often pigmented in spots. 



The dental formula is the same as that of the 

 The incisor teeth form a narrow and strongly 



ox. 



curved arch.. The crowns are long and narrow; their 

 labial surfaces are strongly convex and end at a sharp 

 edge which is used in cropping the grass. The roots 

 are more firmly embedded than in the ox. The cheek 

 teeth resemble those of the ox, but have a thinner 

 layer of cement, which is often blackened by deposits 

 from the food. The average periods of eruption of 

 the teeth are indicated in the subjoined table: 



Fig. 404. — Palate of Sheep. 

 1, Dental pad; 2, papilla in- 

 cisiva: 3, 3, openings of incisive 

 canals; 1, raph6 palati; 5, phil- 

 trum; 6, conical papillae of cheek; 

 7, tonsils: S, palatine arch. 



Teeth Tempohart Permanent 



Ii At birth or first week 1 to 1 } 2 years 



I2 First or second week 1 3'2 to 2 years 



I3 Second or third week 2i'-2 to 3 j^ears 



I4 Third or fourth weelc SJi to 4 years 



P2 f 2 to 6 weeks 1 1 o to 2 years 



P3J 



Ml 3 months (lower), 5 months (upper) 



Ma 9 to 12 months 



Ms 1}-^ to 2 years 



The salivary glands resemble those of the ox in general. The parotid gland 

 is darker in color and more compact in texture than the mandibular. It is rounded 

 in outline, but has a pointed cervical angle at which the external jugular vein 

 emerges. The duct leaves the lower part of the anterior border of the gland and 

 runs forward over the masseter muscle, about an inch and a half (ca. 3.4 cm.) 

 above the ventral border of the ramus; it opens opposite the third or fourth 

 cheek tooth. 



The tonsil is bean-shaped and about half an inch (ca. 12 mm.) in length. It 

 ' A lateral view of the teeth is given in the description of the skull. 



