408 



THE DIGESTIVE APPARATUS IN MAMMALIA. 



Interior. Viewed internally, the caecum offers for study the valvulce or 

 transverse ridges corresponding to the external furrows. We have already 

 seen that these are due to simple circular folds, comprising in their thick- 

 ness the three tunics of the organ, and that they are susceptible of being 

 effaced by distention, to re-appear afterwards in varying number and position ; 

 differing widely, in this respect, from the valvulas conniventes of the small 

 intestine. 



Two orifices, placed one above the other, open on the internal surface of 

 the cescum, at the point corresponding to the concavity of the crook. The 



Fig. 204 



GENERAL VIEW OF THE INTESTINES OF THE HORSE ; SEEN FROM THE RIGHT SIDE, 

 WITH THE PELVIC CURVATURE AND A PORTION OF THE SMALL INTESTINE 

 CARRIED BEYOND THE ABDOMINAL CAVITY". 



a, (Esophagus ; 6, Right sac of the stomach ; c, Small intestine, showing its origin, 

 or duodenal portion encircling the base of the caecum ; d, Csecum ; e, Origin of 

 the large colon ; /, First portion of the large colon ; g, Suprasternal flexure ; h. 

 Second portion of the large colon ; ', Pelvic flexure ; j, Third portion of the large 

 colon ; k, Diaphragmatic flexure ; /, Fourth portion of the large colon ; m, Ter- 

 mination of the free colon ; TZ, Rectum ; o, Mesentery proper ; j?, Colic mesentery 

 (meso-colon) ; r, Neck of the vaginal canal ; s, Spermatic vessels ; t, Deferent 

 canal ; w, Bladder ; v, Vesiculse seminales ; #, Pelvic enlargement of the deferen 

 canal ; y, Prostate ; z, Suspensory ligament of the penis. 



most inferior represents the terminal opening of the small intestine at the 

 centre of the ilio-ccecal valve, whose presence in the domesticated animals 

 has, in consequence of a wrong appreciation of analogies, been denied ; it is 

 nothing more than the projection described as being made by the end of the 

 small intestine. The second opening, placed about 1 or 2 inches above 

 the preceding, and puckered around its margin, establishes a communication 

 between this viscus and the colon. If this opening be compared with the 

 capacity of the canal which begins from it, it will be remarked that it could 

 scarcely be narrower. 



