OBSERVED IN THE NORTH POLAR SEA. 513 
and, bending upwards, terminates in what may be deno- 
minated the proper stomach. The latter, an uniform sac, 
inches in diameter, bears, in its shape, and in the thick- 
ness of its coats, a strong resemblance to the gizzard of a 
fowl, but does not exhibit the same muscular structure. 
It consists, first, of a thin peritonaeal coat, — then of a firm 
coat, of a clear gelatinous appearance, which forms the 
principal part of the thickness of its parietes, and when 
boiled separates into layers : next to this, there is a very 
firm, almost cartilaginous, layer; and the inner membrane 
of the whole is of a grey colour, and thick spongy sub- 
stance, differing in appearance from the lining of the nar- 
row part of the viscus. The rugae of the oesophagus are 
continued into the dilated part of the stomach, but from 
their expansion they become nearly obsolete. 
The pylorus is placed in the fundus of the oviform part, 
where it is nearly in contact with the thoracic septum or 
diaphragm. 
The coats of the first intestine are thin, and the internal 
one exhibits a few longitudinal rugae. A short way below 
the pylorus, it is encircled by the caeca, which continue to 
be inserted into it for about two-thirds of its length down- 
wards. There are about 150 of them, an inch long, of a 
conical figure, and generally filled with a yellowish mucus. 
They are too slender to admit the grosser contents of the 
stomach. 
The first intestine ends in a rectum. There is no valve 
at their junction, but the latter is easily distinguished by 
the well-marked folds of its internal membrane encircling 
the canal. 
The first intestine is in proportion to the length of the 
body, as 9 to 16; the first and second together, as 12 to 
16; and the whole alimentary canal as 19 to l6. These 
proportions, hoM^ever, are only approximations, as the 
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