794 Proceedings of Royal Society of Edinburgh. [sess. 
small granules of pigment may be seen around tire nuclei. More 
deeply a regular rete Malpighii obtains, the cells of which are poly- 
hedral in shape, and have short “prickles” at the margin. The 
deepest layer of the epithelium consists of cubical or slightly 
columnar cells (Plate II. fig. 1), the nuclei of which stain deeply; 
some appear to have a single nucleolus, surrounded by a clear 
space, others again a delicate intra-nuclear plexus. The numerous 
papillae which extend the surface for the production of epithelial cells, 
appear to project upwards as delicate filiform processes, ramifying 
somewhat irregularly, as is evidenced by the great subdivision of 
the mass of epithelium in the deeper parts. This subdivision is 
frequently so marked that masses of epithelium seem to be cut 
off from the rest, presenting the appearance of gland acini, 
for which, in allied species, they have by some observers been 
mistaken. 
The (Esophageal Paunch . 
This, the dilated termination of the oesophagus, consists of a single 
compartment, constricted in such a manner that two cavities are 
formed, viz., a main portion and an outgrowth or diverticulum ending 
blindly. Both these lie in the direct line of the oesophagus, and the 
diverticulum or appendage may therefore be regarded as its caecal 
termination. The main cavity, which is somewhat rounded in form, 
measures internally 9 inches in its longest diameter by 5J inches 
in its shortest, whilst the appendage or diverticulum, cylindrical 
throughout, is 11 inches by 4 inches. Within the main cavity, 
some 3 inches from its oesophageal end and opening at right angles 
to the line of the oesophagus, is found the orifice leading into the 
first true digestive cavity of the stomach. The diameter of this 
opening is 2J inches, notwithstanding the elevation of the mucous 
membrane round its margin to be afterwards mentioned. Through- 
out the main cavity, the mucous membrane, as in the oesophagus, is 
white and opaque in appearance, but, at the opening leading into 
the second compartment, its character changes abruptly, and forms 
a ring-like band leading to the summit of an elevated fold of 
mucous membrane, fully 1 inch in height, which may perform, to 
some extent, the function of a valve. The longitudinal folds of 
mucous membrane already mentioned as occurring in the oesophagus 
