Page 342. 
342 ON THE ANATOMY OF PLOTUS ANHINGA. 
depth of the cylindrical glands which compose its walls. The-yellow 
stomach-epithelium surrounds its orifice and goes no further. There 
are no indications of additional proventricular glands at the lower ter- — 
mination of the oesophagus, the epithelium in that part being quite 
smooth and apparently squamous. 
This further development in Plotus of a special and well-differen- 
tiated gland-organ from what in other birds is a zone or a simple 
circular patch of glands, is very similar to the equally uncommon 
development of the cardiac gland-organ in the stomach of the Manatee, 
which is most certainly only a modification of the similarly situated 
gland-patch in the Dugong. 
The stomach is not developed into a gizzard, its walls in no part 
exceeding one-sixth of an inch in thickness. It is divided into two 
compartments, a cardiac and a pyloric, as is that of the Pelican. The 
former of these corresponds to the gizzard in most birds, the latter to 
the imperfectly formed cavity associated with the pyloric valve in the 
Storks, Gannet, &c. (vide Plate [20] XXVIII. fig. 2). 
Of the stomach of the Pelican, Hunter tells us* that “it is oblong 
much in the direction of the esophagus, with a little curve, smallest 
at the lower end: it makes a quick turn and swells again into a round © 
bag; or it may be supposed that from the side near the lower or smaller 
end is attached a bag whence the duodenum arises.’”’ In the Catalogue 
of the Museum of the Royal College of Surgeons (1852), Prof. Owent 
remarks, with reference to a specimen (No. 519) of the stomach of a 
Pelican (Pelecanus onocrotalus), ‘ The cesophagus is continued into the 
proventriculus or glandular cavity, without any marked constriction; 
and the latter passes insensibly into the part analogous to a gizzard. 
This part communicates by a transverse aperture with a small globular 
cavity, which is lined by a vascular membrane, and communicates 
with the duodenum by a very small oblique aperture. This super- 
added cavity renders the analogy between this stomach and that of 
the Crocodile complete, with the exception of the absence in the latter 
of distinctly developed gastric glands. These, in the Pelican, are 
simple elongated follicles, closely compacted together, and extended 
over a large surface.” In Plotus the second cavity is similarly 
situated, intervening between the stomach proper and the duodenum. 
The dense yellow epithelium of the one, however, extends into the 
other, right up to the pyloric valve. [It may be that in the specimen 
described by Prof. Owen the lining had been previously stripped off, 
which may have led to the term vascular being applied to the mucous 
membrane of the second stomach. } 
* “ Essays and Observations,’ Owen’s edition, 1861. 
t Vol. i. “Organs of Motion and Digestion,” p. 148. 
