DR. J. MURIE ON THE ANATOMY OF THE SEA-LION, 513 
=2°0, 0-9, 1:0, 0°8, 0°8, 0-95, 1:1, 1:6. ‘Thus these bones present the same relations 
as regards size in the young and older animal. It is not so, however, with the cartilages, 
which in the young Otary are each equal to half the length of the bone, but in the 
adult no more than a third. 
The sternal cartilages are thick, long, and flexible; but the last three are shorter 
than the others, and comparatively free. The first cartilage articulates with the pre- 
sternal bony facet. The second, third, and fourth are attached to the middle of the 
intersternal cartilages. The fifth, sixth, and seventh join the intersternal cartilages 
more obliquely, and are inserted chiefly into the hinder corners of the 4th, 5th, and 
6th sternal bones. The eighth cartilage is fixed to the rounded postero-outer border 
of the seventh bone; the 9th to the middle of the cartilage. 
The cavity of the thorax and abdomen enclosed by the ribs, is long, deep, and narrow, 
according as the ribs are expanded or otherwise, heart-shaped, =22 inches long. The 
ribs either stand out or are flattened. This is chiefly permitted by the looseness of the 
cartilaginous and ligamentous union, also length and flexibility of the sternal cartilages. 
3. Bones of the Extremities. 
a. Pectoral Limb.—Scapula. This has not the arched or semilunar shape of the 
Common Seal, but is a broad irregularly trapezoidal thin bone. It measures in our 
specimen 6°5 inches from the glenoid head (the cartilage in situ) across to the middle 
vertebral or posterior border, and it is 8 inches in diameter between the superior and 
inferior angles. The spine is of moderate nearly uniform height, and possesses a 
downward slant, overarching very slightly the infraspinous fossa. It is carried onwards 
to within 3 an inch of the glenoid cayity, whence an acromion process rather broader 
than the spine itself reaches almost to the articular fossa. In the recent state a 
ligament converts this acromial arch into a foramen. ‘The glenoidal cavity is shallow 
and more oval in shape than in Phoca vitulina. The neck is very short, broad, and 
stout. Only a rudiment of the coracoid process is present. The supraspinous fossa 
occupies the upper three fourths of the bone’. A slightly raised ridge proceeds from 
the upper third of the neck backwards and towards the superior angle, dividing the 
supraspinous fossa into two shallow concavities. The narrower, but deeper, infraspinous 
fossa has the oblique ridge and groove for the teres major distinctly marked. The 
space lodging the infraspinatus muscle is hollow, and not convex. 
Humerus. Figured in three different views by De Blainville (op. cit. pl. viii.), is 
short, stout, and peculiar-looking from the great development and prominent nature 
of the deltoid eminence. The greatest length of the bone in a straight line is 63 inches, 
being + of an inch less than the radius, and 1? inch shorter than the ulna. The 
1 Vide Cuvier, ‘ Ossemens Fossiles,’ tom. y. pt.i. p. 224, and De Blainyille, op. cit. text, tom. ii. p. 23, Atlas,’ 
vol. ii. pls. iii, & viii, 
