SKELETON OE. CARNIVOIIA. 507 



The scapula is broad and curved backward, the anterior and 

 basal borders are continued in Phoca by a bold convex line 

 to the angle terminating the posterior costa, which is as strongly- 

 concave, fig. 335. In Otaria the breadth is increased by the 

 production of the fore part of the sciipula, causing a dispropor- 

 tionate extent of the prespinal surface, on which is a low acces- 

 sory ridge, anterior to the true ' spine,' not posterior to it as in 

 Megatherium. The spine is farther from the posterior costa in 

 Trichecus, In all PhocidcE it terminates in a short acromion. 

 The humerus is shorter than the scapula in Phoca, longer in 

 Otalgia ; it is remarkable for the great development of the inner 

 tuberosity and of the deltoid ridge, which is deeply excavated on 

 its outer side. The inner condyle is perforated in Phoca, not in 

 Otaria, Monachus, and Trichecus. The middle of the distal 

 end is excavated by the articular trochlea : an olecranal fossa is 

 feebly or not at all marked. The antibrachial bones are com- 

 pressed, and firmly united, the interosseous space being widest in 

 Otaria : the olecranon is large and hatchet-shaped. The fore- 

 part of the lower half of the radius is produced. The scaphoid 

 and lunar bones are connate : the fifth metacarpal articulates with 

 the cuneiform as well as with the unciform: the magnum is the 

 least of the carpals. Alt/iough the pollex or the first digit exceeds 

 the third, fourth, and fifth in length, it presents its characteristic 

 inferior number of phalanges, by wdiich the radial border of the 

 fin is rendered more resisting. The pelvic arch is remarkable 

 for the stunted development of the ilia, and the great length of 

 the ischia and pubes : the symphysis is short, and divaricable in 

 parturition, as in the Guinea-pig (p. 380). The femur is equally 

 peculiar for its shortness and breadth : its head has no pit for a 

 ' round ligament.' The tibia and fibula present the more usual 

 proportions, but are anchylosed at their proximal ends. The 

 astragalus, fig. 173, a, has its proximal articular surfiice in two 

 facets, one for the tibia, h, the other for the fibula, m : a part of 

 the bone projects ^ proximad ' of these surfaces ; and it is produced 

 * distad ' to articulate with the naviculare, s : the co-extended 

 calcaneum, cl, is applied to the tibial side of the astragalus. In 

 Otaria the calcaneal process is longer. The entocuneiform, /, 

 mesocuneiform, ectocuneiform, c, and cuboides, b, have the usual 

 connections. The bones of the foot are much developed, and arc 

 modified to form the basis of a large and powerful fin : in Phoca, 

 the middle toe is the shortest, and the rest increase in length to 

 the margins of the foot : in Otaria and Tricliecus the toes are 

 subequal in length. The long-bones of Seals have no medullary 

 cavity. 



