1888 - 89 .] Woodhead and Gray on Stomach of Narwhal. 799 
In most of the stomachs examined, the first compartment con- 
tained the less digestible portions of the cuttle-fish ( Gonatus 
fabricii ), the horny mandibles and the crystalline lenses, the latter 
sometimes several hundreds in number. There were also found the 
dermal skeletons of crustaceans, usually Pasiphae tarda (Ivroyer) 
and Hymourdora glacialis (Buch.). 
Scoresby mentions the remains of fishes as found in the 
oesophageal receptacle. 
The fact that we have these considerable accumulations of 
indigestible matter in the oesophageal cavity points in the direction 
we have indicated. 
Remembering the absence of any oesophageal dilatation in the 
t 
Ziphioid whales, e.g ., Hyperoodon, and thg fact, as observed by one 
of us, that Hyperoodon, like the Narwhal, feeds mainly on the cuttle- 
fish, Gonatus fabricii, it becomes evident that this difference in 
structure cannot be accounted for by any difference in the nature of 
the food, as Turner suggests. We should suggest rather, that the 
oesophageal paunch and the wide gullet are probably associated with 
a habit of bolting and storing up the food, digestion being allowed 
to go on at leisure. 
The Cardiac Cavity. 
The Second Compartment , but the First True Digestive Cavity of 
the stomach, is cylindrical in form, measuring internally 9 inches by 
3J inches. At the oesophageal end is situated the opening already 
referred to, by which this cavity communicates with the previous 
compartment ; at the distal or pyloric end is the opening leading 
into the third compartment, a constricted orifice which scarcely 
admits the forefinger. The mucous membrane of this compartment 
has a florid and vascular appearance, is soft to the touch, and is 
thrown into irregularly convoluted folds, which have a slight tend- 
ency to converge towards either end of the compartment. Numerous 
minute follicular depressions are evident, especially between the 
ridges of mucous membrane. 
Structure of the Coats . — The fibrous, muscular, and submucous 
coats are as in the preceding compartment. The mucous membrane 
is exceedingly soft, and nearly as thick as the whole of the remain- 
ing portion of the wall of the compartment (Plate II. fig. 2). It 
