634 



3875. The skull of a young female Walrus of about the same age. 



The left premaxillary has a conical incisor anterior to the four normal molars. The small, 

 low, conical, enamelled summits of these teeth are still retained, and show one or two longi- 

 tudinal impressions on the inner side. There is the mark of a bony cicatrix behind the last 

 molar, as if there had been an obliterated alveolus. The lower jaw has the four normal mo- 

 lars on each side, the last being the smallest : they likewise show their primitive enamelled 

 summits. 



Presented by the Lords of the Admiralty. 



3876. The skull of a young Walrus (Trichecus Rosmarus}. 



Each premaxillary shows the cicatrix of the small obliterated incisive alveolus anterior to 

 the first of the four normal grinders, and there is a shallow, partly bifid, socket of a small 

 molar behind the same series on each side. The lower jaw shows the four normal molars on 

 each side. Remains of the enamelled summits are retained on most of these teeth. 



Hunterian. 



3877. The cranium of a young female Walrus (Trichecus Rosmarus}. 



The socket of the first of the four normal molars is wholly in the premaxillary, giving 

 further proof of the accuracy of the determination of this tooth as the outer incisor. A ver- 

 tical section has been removed from the right mastoid, showing the compact structure of its 

 base, and the coarse structure of its terminal tuberosity. 



Presented by Sir John Richardson, M.D., F.R.S. 



3878. The upper and lower jaws of a large Walrus (Trichecus Rosmarus}. 



The posterior section exposes the large and complex turbinals, and the thick and compact 

 bony ' septum narium.' The turbinals quite block up the entry to the nasal meatuses. 

 There is the remnant of a small circular socket behind the four normal molars, but this is 

 not repeated in the lower jaw of this specimen. 



Hunterian. 



3879. The upper and lower jaws, with the dried skin covering them, of a female 

 Walrus (Trichecus Rosmarus}. 



This shows only the four normal grinders on each side of both upper and lower jaws. 



Hunterian. 



3880. The upper jaw of a male Walrus (Trichecus Rosmarus}. 



The sockets of the small incisors anterior to the four normal molars are well preserved and 

 deep. The canines are more slender, more recurved, and more incurved than usual. The 

 posterior section shows the abrupt descent of each nasal meatus into the palatal process of 

 the maxillary, and the compact character of the osseous tissue. 



Presented by Henry Cline, Esq. 



