DIGESTIVE SYSTEM OF THE DOG — THE MOUTH 



423 



THE PANCREAS 



The pancreas is elongated, and is situated transversely on the dorsal abdominal 

 wall, with its right extremity on the ventral surface of the right kidney, and th(^ left 

 end touching the dorsal end of the spleen and the left kidney. The right portion 

 has two lobes; the posterior lobe bends around the great mesenteric artery and 

 the portal vein; the anterior one is pointed, extends downward and forward about 

 in the median plane, and is attached to the portal fissure and the duodenum. The 

 left portion is prismatic and rests mainly on the left sac of the stomach, its left 

 extremity being included between the left kidney and the dorsal end of the spleen. 

 The pancreatic duct passes from the anterior lobe 

 directly through the duodenal wall, opening about five 

 or six inches (ca. 12.5 to 15 cm.) from the pylorus. The 

 interlobular tissue usually contains a good deal of fat. 



THE SPLEEN 

 The spleen is long and narrow. Its long axis is 

 nearly dorso-ventral in direction, and is slightly curved 

 to conform to the left part of the greater curvature of 

 the stomach. The dorsal end lies under the vertebral 

 ends of the last three ribs. The ventral end is smaller, 

 reaches to the ventral abdominal wall, and lies against 

 the left lobe of the liver. The visceral surface has a 

 longitudinal ridge on which the hilus is situated; this 

 divides the surface into nearly equal gastric and in- 

 testinal areas. The spleen is attached so loosely to 

 the stomach that it may be regarded as being inter- 

 calated in the great omentum. In large subjects it may 

 reach a length of 15 to 18 inches (ca. 38 to 45 cm.) and 

 a width of 3 to 4 inches (ca. 8 to 10 cm.). 



Fig. 32G. — Tongue of Dog. 

 a, Tonsil; h, vallate papil- 

 liT'; f, foliate papilla; rf, fungiform 

 l)ai)illas e, median groove of dor- 

 .suin; /, epiglottis; g, soft ijapillx 

 of root; /(, middle glosao-epi- 

 glottic fold; /,tip; 2, root. (Ellen- 

 berger-lianm, Anat.d. Haustiere.) 



DIGESTIVE SYSTEM OF THE DOG 

 THE MOUTH 



The size and form of the mouth vary greatly in 

 different breeds, the cavity being in some long and 

 narrow, in others short and wide. The rima oris is 

 very extensive, so that the labial commissure is oppo- 

 site the third or fourth cheek tooth. The lips are thin 

 and mobile, and present numerous tactile hairs. The 



upper lip has a small, central, bare area which forms part of the muzzle, and is 

 marked by a central groove, the philtrum, or (as in the bull-dog) a fissure, giving 

 the appearance of harelip. The lateral jjorders of the lower lip are flaccid and 

 denticulatetl. The mucous membrane is usually pigmented and forms distinct 

 frena laljiorum. The lal)ial glands are small and scanty. 



The cheeks are loose and capacious, and their mucous lining is smooth and 

 more or less pigmented. The parotid duct opens usually opposite the third upper 

 cheek tooth. Near the last tooth are the openings of the four or five ducts from 

 the orbital gland. 



The hard palate is widest between the fourth pair of cheek teeth. It has 



