Pnenmatic Mechanism in the Feet of the Walrus. 235 



the thick skin thrown into rugae upon the palm was dissected 

 off, the flipper lost all appearance of a foot, and took on that 

 of the hand of a giant, so far as respected the bones and 

 muscles, differing indeed in having a web covering all the 

 other parts, and extending beyond the point of the thumb and 

 fingers. The span, instead of being twelve inches, became 

 twenty-eight. The resemblance of the bones of the hind flipper 

 of a walrus to those of the human hand, (which I believe is like 

 nothing else in nature,) is curiously exact : the bones of the. 

 wrist are the same in number and shape ; so are those of the 

 metacarpus; so also the phalanges of the thumb and fingers. 

 The tendons of the perforantes muscles pass through those of 

 the perforati in the palm upon the metacarpal bones, while in 

 the human hand this takes place upon the first phalanges of 

 the fingers ; and there are no lumbricales muscles whatever. 

 On the back of this giofantic hand I was astonished to find the 

 tendon of the indicator muscle. 



" The muscles and tendons that are peculiar to this flipper, 

 not met with in the human hand, are those of the web which 

 extends beyond the fingers and thumb : this web is a strong 

 ligamentous elastic substance intermixed with muscular fibres ; 

 it has a set of muscles, which have their origin from the sides 

 of the last phalanges of the fingers insensibly lost in it, and 

 tendons go off from each side of the perforator muscles, which 

 spread out and are lost in it. 



" That this gigantic hand is employed as a cupping-glass to 

 prevent the animal from falling back in its movements, whe- 

 ther on the ice or in climbing the rocky cliffs, there can be 

 no doubt ; for it is only necessary to take the human hand, and 

 envelope it in an elastic web extending some way beyond the 

 points of the fiiigers, to prove that it could perform such an 

 office : but when we find the lumbricales muscles wanting, the 

 only use of which is to clench the fist, it adds to the proof; 

 and when the indicator is met with, a mode of opening a valve 

 to let the air in is pointed out. 



" It may be doubted whether the extent of the flippers is 

 equal to the support of the enormous bulk of this animal ; but 

 this doubt will be removed when I mention that Mr. J^isher 

 informs me that a walrus killed at Spitzbei gen weighed twenty 

 hundred weight, and that an exhausted surface of twenty-eight 

 inches by twenty will support a pressure of 15lbs. on every 

 square inch, more than doui^le the animal's weight. 



" Tiiat the principle on which the foot of the ily, the gecko, 

 and the walrus is formed, is the same, 1 trust has been es- 

 tablished. In the flv there are two cups, in the walrus only 

 one." 



Vol. 65. No. 323 March 1825. G g Results 



