406 DR MORRISON WATSON AND MR ALFRED H. YOUNG 
of the mucous membrane presents a cribriform aspect, due to the presence 
of a number of little apertures which are visible to the naked eye. These 
openings, which do not extend farther than 2 inches from the pylorus, ap- 
pear to be the orifices of glands, in all probability corresponding to those of 
Brunner in other mammals, but the somewhat unsatisfactory state of the 
part prevented the recognition of such by means of the microscope. The 
Peyerian patches are eighteen in number. They are large, irregular in form, 
and the long diameter of each coincides with that of the intestine. They are 
mostly situated on the free side of the gut. The largest patches, measuring 
for the most part about 9 inches in length, are found near the duodenal 
extremity of the intestine. Those of the lower half of the gut do not exceed 
2 or 3 inches in length. The largest patch of all, however, measuring 16 
inches in length, and occupying the entire circumference of the intestine, 
terminates at a distance of 11 inches from the anus, beyond which point these 
glands are entirely wanting. The first Peyerian patch is situated 5 feet beyond 
the pyloric valve. 
The intestinal arteries are very regular in their arrangement. They 
inosculate with one another so as to form a series of vascular arches, 
the summits of which abut against the wall of the intestine. From these 
arches numerous branches are given off for the supply of the gut, without 
the intervention of any secondary arcades. The veins are arranged in a similar 
manner. 
The mesenteric lymphatic glands are aggregated so as to form a mass, 
measuring 13 inches in length and 3 inches in breadth, surrounding the 
main trunk of the mesenteric artery. The margins of this mass are irregular 
in consequence of the presence of outlying processes, which for the most 
part are prolonged toward the gut, and accompany the main branches of 
the mesenteric artery. In addition to this glandular mass, isolated lym- 
phatic glands of large size are dispersed here and there between the mesen- 
teric folds of peritoneum. The lymphatic vessels are very numerous, and 
run in bundles from the walls of the gut to the central glandular mass. They 
are richly provided with valves, which entirely prevent the passage of injec- 
tion toward the gut, although it passes with the greatest ease in the opposite 
direction. The neighbouring lymphatic vessels communicate freely with one 
another. 
According to MEcKEL,* in the cetacea the length of the intestine is to 
that of the body as 11 or 12 to 1; but an examination of the accompany- 
ing table will show that, except in the case of the porpoise, this estimate is 
too high :— 
* XVIIL vol. vii. p. 388. 
