100 
ANATOMY AND PHYSIOLOGY 
of eighteen or twenty-four feet long than in the horse ; 
the colon not much more capacious than the jejunum 
and ilium, and very short, a circumstance common to 
carnivorous animals. The structure of the inner surface 
of the intestines is in some very singular, and different 
from that of the others. The inner surface of the duo- 
denum in the piked whale is thrown into longitudinal 
rugm or valves, which are at some distance from each 
other, and these receive lateral folds. The duodenum 
of the bottle-nose swells out into a large cavity, and 
might almost be reckoned an eighth stomach, but as 
the gall ducts enter it, I shall call it duodenum. The 
inner coat of the jejunum and ilium appears in irregu- 
lar folds, which may vary according as the muscular 
coat of the intestine acts, yet I do not believe that their 
form depends entirely on that circumstance, as they run 
longitudinally, and take a serpentine course, when the 
gut is shortened by the contraction of the longitudinal 
muscular fibres. These folds in the bottle-nose act 
almost like valves when anything is attempted to be 
passed in a contrary direction. They begin faintly in 
the duodenum, before it makes its quick turn and termi- 
nates in the anus. The colon and rectum have the 
rugse very flat, which seems to depend entirely on the 
contraction of the gut. The rectum, near the anus, 
appears for four or five inches much contracted, is 
glandular, covered by a soft cuticle, and the anus small. 
I never found any air in the intestines of this tribe, nor 
indeed in any of the aquatic animals. The mesenteric 
artery anastomoses by large branches. 
