DR. J. MURIE ON THE ANATOMY OF THE SEA-LION. 531 
his body while supporting it in walking, or simply lies at rest, does the free portion of 
the limb apparently vary in its extent. 
The girth of the pectoral limb, close to the body, is 1 foot 5 inches. Above this 
point it lies flatly adpressed against the walls of the thorax. As it becomes free it 
assumes a definitely, peculiarly broad and flat appearance; and the thickness decreases 
by degrees until, at the distal end of the manus, it has diminished to a few lines. That 
portion of the limb which is more or less free is of an elongated, flat, pyramidal shape, 
the apex being represented by the flap of membrane and cartilage of the enormous 
pollex. 
The length of the anterior border of this portion of the fore flipper, following the 
curve, is 2 feet, whereas the posterior margin, measured in the same way (that is, from 
its basal attachment to its free extremity), is 18 inches. ‘The portion (or the serrated 
margin) corresponding to the extremities of the digits in other animals is 103 inches 
broad from its one end to the other. 
The diameter of this flipper-like extremity, at 13 inches from its free furthermost 
point, where it is widest, is 8 inches. At a distance of 7 inches from the tip the 
diameter is but 54 inches, and near the tip itself it is reduced to only 2 inches; from 
this it tapers and terminates in a slightly rounded extremity. 
At the wrist-joint the thickness of the member is 2 inches; from this the manus thins 
very gradually until, as already said, at the free phalangeal extremity it does not surpass 
1 or 2 lines in thickness. The anterior and also lower margin is thicker than the hinder 
one. From its thoracic attachment to the tip it has a long and low-arched curve, which 
is tolerably smooth at the edge. 
The posterior and upper margin, or what is included between the axilla and the fifth 
digit, is no more than 7 inches long, and is much more elastic than the anterior margin 
already spoken of. This hinder, inner, or axillary margin possesses a small fold of 
nearly loose skin; the anterior or shoulder margin, on the contrary, is firm and tense, 
or with more of the Porpoise-fin-like rigidity. 
There are eight rounded projections, and seven hollow interspaces, at the posterior 
free extremity on that margin, ending in the phalangeal cartilages. ‘The outermost of 
the emarginations is the widest. 
The upper surface of the manus is covered with hair; but on the fore margin there is 
a broad strip devoid of it; and the latter widens, stopping short of the pollicial, but 
almost reaching the other nails. There are few creases, except slightly between the 
moveable portions of the digits. The palmar surface is nearly flat, almost entirely 
hairless, and minutely striated by cuticular elevations. These run in sinuous but 
parallel lines, longitudinally or with a moderate curvature, following the contour of the 
palm. Here and there the ridges interdigitate at acute angles. ‘The length of this 
bare palm, taken in a straight line towards the fore border, is 15 inches, but no more 
than 4 inches on the opposite (hind or radial) side. 
