ALIMENTARY CANAL OF PERISSODACTYLA. 



459 



produced beyond the cardiac part : and this distinction is main- 

 tained by more important characters of internal structure. The 

 oesophagus, b, is inserted at an acute angle into the smaller cur- 

 vature., which rather resembles a deep cleft. 1 The cardiac cul-de- 

 sac, c, is very capacious, and is lined throughout internally with a 

 thick cuticular layer continuous with the lining of the oesophagus, 

 and extends toward the pylorus as far as the middle of the 



3-39 



Colon of the Mare in situ. cxxn'. 



cavity, where it terminates abruptly by a prominent indented 

 edge : the interior of the pyloric half of the viscus, a, d, presents 

 the usual villous mucous surface. The muscular coat of the 

 stomach consists of several superimposed layers of fibres that 

 cross each other in different directions, some of them being appa- 



1 Vomiting is rare and difficult ; biit has been observed in sea-sick horses slung on 

 board transport-vessels. 



