232 Mechanism of the Foot offhe Walrus. 



analogous pi'ovision in the walrus, given in a paper on some 

 curious facts respecting that animal and the seal, published in 

 the Phil. Trans, for 1824, part ii. 



" The first discovery I shall mention," says Sir Everard, 

 " is a peculiarity in the structure of the hind flipper or foot 

 of the walrus, that has not been adverted to ; nor could it 

 have been done now by any one not well acquainted with the 

 mechanism of the foot of the fly, enabling it to support its 

 weio-ht, and carry on progressive motion against gravity. Such 

 is the general resemblance between this flipper and the foot of 

 the fly, that having upon a former occasion seen it in a very 

 mutilated state, macerating in water, I discovered this analogy, 

 and requested my friend Captain Sabine in the Artillerj', at 

 the time he sailed with Captain Clavering to make experi- 

 ments on tlie figure of the earth, to bring me the feet and 

 other parts of the walrus. With the assistance and exertions 

 of Mr. Rowland, assistant-surgeon to the ship, he has com- 

 plied with my request, and enabled me to bring forward the 

 following observations on this subject. 



" It is a curious circumstance that two animals, so different 

 in size, should have feet so similar in their use. In the fly, the 

 parts require being magnified one hundred times to render 

 this structure distinctly visible; and in the walrus, the parts 

 are so large as to I'equire being reduced four diametei's to 

 bring them within the size of a quarto page. 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 1 did not suf- 

 ficiently understand — I mean the two points : Mr. Adams 

 called tliem 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 conside- 

 ration, but was unable to make out their real use : on com- 

 paring 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 suddenly and perfectly formed. 



" As the skin of the animal is very thick and imyielding, and 

 had been for so long a time in strong brine, the parts were much 

 shrunk and corrugated ; but even in this state they showed 

 that the palm of the flipper formed a concavity, which had the 

 appearance of a cup when the great and little toes were made 

 to encircle the others. In this state of the parts this concavity 

 was thrown into longitudinal rugae, so that the real size could 

 not be ascertained, the span from the point of the great toe to 

 the end of the little toe not exceeding twelve inches. After 



the 



