266 PROF. OWEN ON THE ANATOMY 
from the stomach by a circular strip of epithelium, whiter and thinner than the rest, 
from one to two lines in width: the structure is well shown in Plates LI. and LII. of 
the ‘Comparative Anatomy’ of Sir Everard Home. The Apteryx, though resembling 
these large Struthious birds in the arrangement of its gastric glands, does not participate 
with them in this structure. The muscular stomach’ does not present the characteristic 
sub-compressed shape of a gizzard, but resembles, in its regular oval-rounded form, 
the membranous stomach of carnivorous birds. In its contracted state it appears 
small for the size of the bird, not exceeding 1 inch 10 lines in length, and 1 inch 3 
lines in its greatest diameter; but in the specimen in which I found the stomach 
distended with food it measured 23 inches in length, and 2 inches across at the widest 
part. The muscular fibres are not arranged in the well-defined masses called digas- 
trici and laterales in the true gizzard, but radiate from two tendinous centres of an 
oval form, measuring about two-thirds of an inch in the longest diameter. The mus- 
cular coat when contracted is thickest at the upper part of the cavity, where its depth 
is about 3 lines: in the bulging part at the upper end of the gizzard from which the 
duodenum is continued, the muscular coat is about | line thick. The inner surface of 
the contracted stomach (b, Pl. LI.) presented two protuberances at its posterior part, 
one near the lower and the other near the upper end: the latter is so situated with re- 
spect to the cardiac and pyloric openings that it would tend more or less completely 
to close those openings when the circular fibres at the upper part of the gizzard were 
forcibly contracted. There was no appearance of these internal projections in the di- 
lated stomach of the second Apteryx dissected by me. 
A narrow pyloric passage, of about 3 lines in length, leads from the left side of the 
upper extremity of the muscular stomach into the duodenum*. The pylorus is defended 
by a transverse crescentic ridge of the lining membrane ; there is no distinct sphincter. 
The cuticle is continued into the duodenum about 3 lines beyond the pylorus, but there 
is no dilatation of this part constituting a pyloric pouch as in the Emeu and Ostrich. 
Before proceeding with the special description of the intestinal canal, the general 
disposition of the abdominal viscera may be mentioned, as they appear upon removing 
the abdominal muscles. 
The peritoneum consists of an external strong fibrous and an internal serous layer. 
The abdominal cavity’ is divided by peritoneal partitions into three compartments, 
which contain, besides the ordinary viscera, only a little fluid; and when the thoracic 
cells were inflated from the trachea no air passed into the abdominal cells or their in- 
terspaces. The two upper compartments contain the right and left lobes of the liver, 
which are separated from each other by a strong mediastinal process of peritoneum : 
the ligamentum latum in Mammalia seems to be the representative of this broad process. 
Each hepatic cell communicates with the single large inferior compartment of the 
abdomen by a round aperture situated close to the ribs ; this lower compartment was 
1 Pl. L. & LI. 8. 2 PLL. & LI. ¢. 3 Pl. XLIX. 
