closely correspond with those in the skull of the Ursus spelceus, as to 

 lead to the conclusion that the difference in the development of the frontal 

 sinuses, the large size of which occasions the convexity of that region 

 of the skull in the old male, is in the present instance attributable rather 

 to age and sex than to specific distinction. 



4. The posterior part of the cranium of the Cave Bear. 



This is the original specimen described and figured by John Hunter, 

 loc. cit., pi. xx. fig. 1. The development of the sagittal crest has only just 

 commenced at its junction with the lambdoidal crest : the upper surface 

 of the skull covered by the parietal bones is smooth and convex : the 

 sutures are not obliterated, and show that the sagittal crest commences at 

 a sharp tooth-like process of the supra-occipital bone, passing forward 

 like a wedge into the posterior interspace of the parietal bones ; all these 

 circumstances lead to the conclusion that the present specimen formed 

 part of the skull of a young individual. As compared with the cranium 

 of a young Grisly Bear (Ursus ferox), of the same size, the present 

 fossil differs in the prominence of the side of the skull just below the 

 squamous suture, and in the smaller breadth of the bony tentorium, 

 especially at its middle part. 



4 1 . The skull of a nearly full-grown Grisly Bear (Ursus ferox, Clarke). 



The differences observable between this skull and that of the (presumed) 

 young Cave Bear of the same age, are pointed out in the description of 



No. 4. 



5. A mass of stalactite enveloping a portion of the cranial cavity and the 

 crown of the canine tooth of the Cave Bear. 



6. Portion of the skull including the left superior maxillary bone, with the 

 three posterior molar teeth, of the Cave Bear (Ursus spelceus). 



7. A portion of the left superior maxillary and palatine bones, including the 

 three posterior molar teeth, of the Ursus spelceus. The tuberculate sur- 

 face of the last grinder is nearly entire, showing the animal to have been 

 young. 



8. A portion of the left superior maxillary bone with the last molar and 



