some curious facts respecting the walrus and seal , &c. 235 
As a knowledge of the structure of the fly's foot, led to 
the detection of the use of the hind flipper of the walrus ; so, 
on the other hand, an examination of the toes of the walrus 
has enabled me to make out the use of a part of the foot of 
the fly which I did not sufficiently understand — I mean the 
two points ; Mr. Adams called them pickers, from supposing 
that they entered certain small holes in the surface, on which 
progressive motion was carried on. This opinion I did not 
deem worthy of consideration, but was unable to make out 
their real use ; on comparing them, however, with the outer 
toes of the walrus, they are evidently intended to surround 
the exhausted cavity, so that a vacuum may be more sud- 
denly and perfectly formed. 
The flipper, whose external appearance is seen, Plate IV. 
was in a very corrugated state ; but in Plate V. in which its 
muscles and bones are shown, they closely resemble those of 
the human hand. 
The second discovery I have to notice, is the mode in which 
the bile in the walrus is collected in a reservoir, and thence 
impelled by a considerable force into the duodenum. The 
internal surface of the stomach of the walrus consists of rugae ; 
these in some respects resemble those of the cod fish ; the 
orifice from the oesophagus is very large, so as evidently 
to admit large masses, and also of regurgitation ; in this 
respect it is so like the seal, as to be distinguished from it 
only by the difference of size : in both these animals the orifice 
at the pylorus is extremely small and valvular, preventing the 
contents of the duodenum from again returning into the sto- 
mach. In the seal the gall bladder is small, detached from the 
liver, and opens, by a very small orifice, two inches and a half 
from the pylorus. In the walrus, a large cylindrical hard body 
