1888 - 89 .] W oodhead and Gray on Stomach of Narwhal. 801 
to that in the same position in the pig and in the porpoise. 
It appeared in many cases as though*, the large parietal cells were 
entirely surrounded by the delicate strands, but it is probable that 
there is the same arrangement here that there is in the animals 
mentioned, and that there is a small orifice in the inner wall of the 
space, bringing the two sets of cells into direct communication. 
Here and there flattened nuclei may be seen lying on the strands of 
this reticulum. 
The Second True Digestive Cavity. 
This cavity, externally concealed, almost, between the second and 
fourth compartments, is cylindrical in form, is curved abruptly 
upon itself, through a right angle, and measures 3 inches in length 
by 1 inch in diameter. The orifice at its proximal end has already 
been referred to in connection with the last compartment; the orifice 
at the distal end, leading into the next compartment, is also small 
in size, being less than 1 inch in diameter. At neither end is there 
a valve-like sphincter. The mucous membrane, florid and vascular 
in appearance, is smooth and almost devoid of rug£e. Although 
small in size, this cavity is not a mere canal forming the means of 
communication between adjoining cavities, but must be regarded as 
a distinct compartment, since it possesses both a proximal and a 
distal orifice and walls proper to itself, with slight structural 
peculiarities. 
Structure of the Walls . — The fibrous, muscular, and submucous 
coats are arranged as in previous compartments, but in the areolar 
tissue of the fibrous coat, which in this case is not continuous with 
the peritoneum (this compartment lying concealed between the 
adjoining portions of the stomach, and not being invested by a 
serous coat), there are numerous large ganglion nerve-cells, and 
the circular fibres of the muscular coat are here especially well 
developed. 
Mucous Membrane . — As in the previous compartment, the glands 
are mostly simple elongated tubules, arranged vertically to the free 
surface, though in some cases they divide. They do not, however, 
hook round at their extremities, and from the presence in most cases 
of only a single set of cells, there is a distinct difference in this struc- 
ture from those already described. The glands of the second com- 
