654 



4008. The left calcaneum. 



4009. The left radius, longitudinally bisected. 



The medullary cavity terminates a little way below the middle of the bone. 



4010. The left femur, longitudinally bisected. 



The medullary cavity is confined to the middle third of the bone. The medullary artery, 

 which enters at the posterior and inner side, below the middle of the shaft, takes an oblique 

 course upwards of two inches before it opens into the medullary cavity : a bristle has been 

 passed through the canal. 



4011. The left fibula, longitudinally bisected. 



The medullary cavity extends through nearly the whole of the shaft of this slender bone. 



4012. The os penis of a Polar Bear (Ursus maritimus). 



Presented by Captain Ross, B.N. 



4013. The skeleton of the American Black Bear (Ursus americanus}. 



The vertebral formula is : 7 cervical, 14 dorsal, 6 lumbar, 13 sacral ; the caudal series is 

 incomplete. Nine pairs of ribs articulate directly with the sternum, which consists of eight 

 bones, besides the xiphoid appendage. The scapula is remarkable for its almost quadrate 

 form, and for the strong development of the ridge between the infraspinatus and teres major, 

 constituting almost a second spine. The inner condyle of the humerus is not perforated. 

 The scaphoid and lunar bones of the carpus have coalesced into a single bone, as in most 

 other Carnivora. The femur is almost straight, and long in proportion to the tibia : the fifth 

 digit exceeds the second in length in both fore and hind feet. The first digit in both fore 

 and hind feet has but two phalanges, as in other mammalian quadrupeds. 



Mus. Brookes. 



4014. The skull of a small, and probably female, American Black Bear (Ursu* 

 americanus}. 



In the interspace between the canine and last premolar there are three sockets on the right 

 side of the upper jaw, and two on the left side, the middle one (p 2) being obliterated ; only 

 the first small socket of p 1 is preserved in the same interspace of the lower jaw. 



Presented by the Lords of the Admiralty. 



4015. A similar-sized skull of the American Black Bear (Ursus americanus). 



The symphysis of the lower jaw has been ulcerated, and the incisors lost. There are three 

 sockets for p 1, p 2, and^p 3, between the canine and last premolar, p 4, on each side of the 

 upper jaw, and two sockets for the first and third premolars in the same interspace of the 



