. FELIS SPELiEA. 3 



not to be trusted to as a specific character. Another point appears to deserve more 

 attention ; it is that in Felis spelaa the coronoid process projects backwards far more 

 beyond the neck of the condyle (PL I, fig. 1, f) than in the lion or tiger ; in the former 

 animal this excess of projection amounting to nearly an inch, while in the tiger it is 

 barely perceptible ; and, as far as we have measured, it does not exceed half an inch 

 in the lion. The different appearance this gives to the bone is very remarkable. The 

 superior border of the coronoid process is a strong, smooth, externally rounded ridge, 

 somewhat stronger than that of the lion or tiger, but almost totally destitute of the 

 strongly marked* ridges which are on this part of the bone in those animals. 



The angle in the larger jaw resembles that of the lion, except that in the lateral aspect 

 it forms one end of an arch (PI. I, figs. 1, 2, g), of which the ramal process [a) forms 

 the other, whereas in the lion and in the small variety this aspect presents a slightly con- 

 cave line (PI. VI, figs. 1, 2, g, a). In the adult tiger the angle descends far lower, and the 

 arch above mentioned extends without interruption to the symphysis. 



The masseteroid ridge is perhaps proportionally somewhat thicker and stronger in the 

 large jaws, and the upper external border of this portion is massive and rounded (PI. I, 

 fig. 1, ii), instead of ending in a sharp and knotted ridge, as in the lion and tiger and 

 smaller cave variety (PI. VI, fig. 1, h). The contour of the lower border of the anterior 

 half of the ramus is precisely the same in the smaller cave jaws and the lion, as well as in 

 the large fossil jaws ; but it is more concave in the tiger. 



The contom- at the symphysis differs in the large form of Felis spelcea from that of 

 either of the others. The angle formed by the front edge of the symphysis and the pro- 

 duced plane of the lower border is much larger in Fells spelcsa than in either Felis leo 

 or the small cave specimens (PI. I, figs. 1, 2, k, e, a). This angle amounts to 70° in 

 Felis spelma, while it is 45° in the smaller fossil forms, and 40° only in the lion; in the 

 tiger it is 55°. This difference, though very striking to the eye, appears to be variable; 

 it is probably of little, if any, specific value. 



The alveolar border is straight in all the forms (Pis. I, VI, figs. 1, 2, c, d). 



The mentary foramina are very variable in form and position (Pis. I, VI, fig. 1, i). In 

 some of the fossil jaws they appear to be each divided so as to form four on each side ; 

 we have seen an approach to this variation in recent specimens of both lion and tiger. 



We may observe here that the silky smooth surface, which is remarkable on the 

 other more robust feline bones of the caves, is also observable on the larger jaws, while 

 the smaller resemble in this respect those of the recent large Peles. 



The jaws we have principally used in our descriptions are from Bleadon and Sandford 

 Hill. Of these, nearly perfect specimens of both varieties exist in the Taunton Museum, 

 being a portion of the collection of Mr. Beard. There are also in the same collection 

 many large fragments which confirm the description taken from the more perfect 

 specimens. 



The fragments of lower jaw, showing the angle, condyle, and coronoid process (PI. I, 



