96 ” THE ZOOLOGIST. 
size (Pseudalius alatus, Leuchart), for the names of both of which 
I am indebted to Dr. von Linstow of Géttingen, through the 
kindness of Mr. John Murray, of the ‘Challenger’ Commission. 
July 9.—Lat. 74° 49’, long. 11° 40’ W. Colour of the water 
slightly grey; temperature, 35°. In the evening we fell in with 
a number of Hooded Seals Cystophora cristata, lying on the loose 
ice at the pack-edge. I examined the stomachs of several 
which were shot. While most were empty, one was packed full 
with a bluish mud or ooze, in which were embedded the crystal- 
line lenses of two eyes belonging probably to some small species 
of fish, and the remains of one crustacean common at the 
surface (Themisto). The stomachs of three other Seals contained 
mud alone. With regard to the presence of mud in these 
animals’ stomachs, while considering the depth of the water too 
great (in this instance 200 fathoms,—in another, to be afterwards 
recorded, 1100) to permit the bottom being reached, the only 
explanation I am able to offer is that the substance must be 
swallowed in small quantities by the Seals along with their 
ordinary food (crustaceans living at the surface), and that, owing 
to its indigestible nature, accumulates in course of time in the 
stomach. These Seals are occasionally observed disappearing 
under the ice, for the purpose, I believe, of feeding on the 
immense number of crustaceans which are known to accumulate 
there. Many of the ice-fields bear on their surface, immediately 
under a superficial coating of snow, cargoes of mud (apparently 
of an alluvial origin). During the process of melting, the mud 
may accumulate on submerged tongues or ledges of the ice, and 
thus become the retreat of numbers of crustaceans, which, as 
they are devoured by the Seals, are swallowed along with a small 
quantity of the mud.* Some such explanation must, I think, be 
conceived. 
July 16.—Lat. 75° 10’, long. 8° 4’ W. Colour of the water, 
slightly green ; temperature, 34°. Saddle Seals very numerous, 
some lying on the ice, others sporting about in the water. There 
was a fair proportion of this year’s Seals present, the average 
length of some which I measured being 8 ft. 2 in. from the tip 
of the nose to the tip of the tail. Unfortunately I did not 
* This conclusion is supported by a comparison of the report on the mud 
from the Seals’ stomachs with that of a sample of mud of the ice. 
