REPORT ON THE SEALS. 15 



joints, and the margin of the segment next the joint was formed of unossificd cartilage. 

 The 9th or xiphisternal segment was situated behind the last pair of sternal ribs ; it was 

 290 mm. long, and whilst its anterior third was ossified, the remainder consisted of 

 cartilage, which widened at its free end into a leaf-like expansion. The first seven pairs 

 of costal cartilages articulated with the side of the sternum at the junction of its segments 

 with each other, the 8th pair was jointed to the side of the 8th segment and the 9th pair 

 at the junction of the 8th and xiphisternal segments. The 8th and 9th costal cartilages 

 also articulated with each other close to the sternum. The maximum sterno-vertebral 

 diameter of the cavity of the thorax was 430 mm. and the greatest transverse diameter 

 of the cavity was 370 mm. 



Anterior Extremity. — The scapula did not have so well-marked a falciform shape as 

 is usual in the seals. The dorsum was divided into two fossae ; the postspinous was 

 deeply grooved immediately below and parallel to the spine, and its vertical diameter 

 was about three times more than its greatest antero-postcrior diameter. The pixespinous 

 fossa was almost triangular in shape, and its vertical diameter was about twice as great 

 as the antero-posterior. The area of the prsespmous was somewhat greater than that of 

 the postspinous fossa. The spine had no great prominence, and was without an acromion. 

 The coracoid was stunted, and in the younger skeletons was not fused with the body of 

 the scapula. The scapula was prolonged by a triangular suprascapular cartilage, and its 

 extreme breadth or vertical diameter, including this cartilage, was 34' 5 cm., whilst the 

 length or antero-posterior diameter was 19 "5 cm. The subscapular and prsespinous fossae 

 were smooth and only slightly concave. 



The humerus was 26 cm. long, and had a strong deltoid ridge with a bicipital groove 

 internal to it. The upper and lower epijmyses were not fused with the shaft ; that of 

 the internal condyle was quite distinct from the radio-ulnar articular epiphysis, and that 

 for the head was separate from that for the inner tuberosity. There was no supra- 

 condyloid foramen and the shaft of the bone was not much twisted. 



The radius, 24 cm. long, was rounded above and had the usual cup-shaped head, and 

 was flattened in its lower half as is usual in seals. The anterior border of the shaft was 

 strongly ridged for the tendon of insertion of the pronator teres. The ulna, 28 cm. long, 

 was expanded above at the olecranon and attenuated below. In both bones of the fore- 

 arm the epiphyses were not united to the shafts. The radius was anterior to the ulna, 

 and its cup was a more important factor in the elbow joint than the articular surface of 

 the ulna. The radius articulated at its lower end with the ulna, scapholunar, and cunei- 

 form ; the ulna articulated with the radius, cuneiform, and pisiform. 



Manus. — The carpus possessed seven bones. The 2^isiform was a mere nodule and 

 articulated with both ulna and cuneiform. The cuneiform articulated with the ulna, 

 radius, scapholunar, unciform, and 5th metacarpal. The scapholunar was large and 

 articulated with radius ; cuneiform, trapezium, trapezoid, os magnum, and unciform. The 



