366 COMPARATIVE SPLANCHNOLOGY. 



The parotid gland is small and red ; the duct follows a similar course to that 

 of the horse, but enters the mouth much more posteriorly ; in small ruminants 

 it crosses the masseter externally. The submaxillary gland is very large and 

 yellow in colour. The canal of Wharton opens close to the incisors, the papillae 

 bein" lodged in an elliptical fossa. The sublingual gland is divided into two 

 portions, the posterior opening by a sipgle duct (the duct of Bartholini) close 

 behind Wharton's, the anterior by a row of ducts as in the horse. 



The dentition of the ruminant is characteristic. With the exception of the 

 camel and llama, which are not usually domesticated in Europe, the ruminant 

 has neither incisor nor canine teeth in the upper jaw, thei former being replaced 

 by a thick cartilaginous pad, covered by the mucous membrane of the hard 

 palate, forming a point d'dppui for the lower incisors to press against in cropping 

 grass, &c. In the lower jaw there are six incisor teeth, and two canines ; the 

 latter closely resembling the former in shape, and being situated immediately 

 behind them, indeed it is customary to describe the incisors as eight in number; 

 it signifies little which view is taken. These teeth are chisel-shaped, rather 

 like the human incisors, but with a curved contour, convex anteriorly, and 

 concave behind, the whole of the crown being covered with enamel ; the neck 

 is small and constricted, and the teeth are arranged in the jaw in an almost 

 horizontal position, forming a radiating, or fan-like series. They are not 

 firmly fixed in the alveoli, but have a certain degree of mobility, thus prevent- 

 ing injury to the cartilaginous pad above. The molars have compound tables 

 like those of the horse, but the teeth are much smaller and more cuboid in 

 shape. 



The dental formula of the domesticated ruminant is as follows : 



.Or-0 0-0 3-3 3-3 



i. r_r, c. ^—^, p.m. r__?, m. ^— ? =.32 

 3-3 l-l'^ 3-3 3-3 



That of the camel is : — 



3-3' 1-1'"^ 2-2 3-3 



(Thomes.) 



The pharynx is large, but the muscles composing it are less distinctly 

 separable. The oesophagus is well developed, and its muscular walls are red 

 throughout. It joins the stomach by expanding, so that its termination is 

 funnel-shaped. The muscular fibres induce both a downward or peristaltic, 

 and an upward or anti-peristaltic motion. 



Stomach. 

 The stomach of the ruminant is a very complex organ, consisting of four 

 compartments, which vary in size, form, and in the disposition of their 

 mucous coats. The first compartment is the rumen, or paunch ; the second 

 the reticulum, or honeycomb ; the third the omasum, psalterium, or many- 

 plies ; the fourth the abomasum, or true digestive cavity. The first three 

 have little to do with the essential process of digestion, being principally 

 concerned in macerating and preparing the food, and are analogous to, the 

 cardiac portion of the stomach of the horse. The runun in the adult is 

 very large, occupying about three-fourths of the abdomen. It is situated 



