2 PLEISTOCENE MAMMALIA. 



process immediately beneath the hist molar, which is developed to a different degree in 

 different individuals ; in some it causes the outhne of the inferior border of the lower 

 jaw to present a regular rounded, convex outline, nearly straight from symphysis to 

 angle, while in others it reaches a maximum of development, so that the jaw approaches 

 the doubly arched appearance so manifest in the figures PI. I, figs. 1,2. In the 

 tiger, on the other hand, the inferior border of the lower ramus is straight, or rather 

 concave in outline, from the symphysis backwards, the only exception out o^ the large 

 number of tigrine skulls in the museums of Oxford and London being that afforded by 

 one in the Hunterian collection, killed in India, and presented by General Hardwicke, in 

 which there is the faintest possible approximation to the leonine contour. 



In this point the rami of Fells spelcsa agree most remarkably with those of Felis ho, 

 and, as far as the larger specimens are concerned, present us with the maximum 

 development of this '' ramaV process, as it may be called (a of figs. 1, 2, PI. I). In 

 these large specimens it is far more strongly marked than in any recent varieties of 

 Felis leo ; but, as the latter present great variations in this respect, we cannot consider 

 the stout proportions which the former exhibit a proof of specific difference. 



The smaller jaws above referred to (figs. I, 2, PI. VI) do not present a greater 

 development of the " ramnl " process than ordinary specimens of the lion ; being in this 

 respect, as in all others, indistinguishable from that animal. In the leopard, both of 

 Africa and of India, the inferior outline of the lower jaws resembles that of the lion ; but 

 that of the jaguar {Felis onca) is straight or slightly concave, like the tiger. 



In both the large and small varieties the height of the condyle above the angle 

 coincides remarkably with that of the lion, but differs in the tiger ; this dimension being 

 in the latter greater, both proportionally and absolutely. The proportion of length to 

 maximum depth of the condyle varies in different individuals ; but in the few instances 

 we have seen, both large and small varieties have this part proportionally somewhat 

 stouter than in the recent species (PI. I, figs. 1, 2, 3, b; PL VI, figs. 1, 2, b). 



Baron Cuvier considers that the gradual ascent of the coronoid process from the 

 alveolar border of Felis spelaa is one point of difference between that animal and the 

 living lion. We cannot see that in this point any difference exists between the fossil and 

 recent species. The coronoid process rises more gently from the alveolar border in the 

 lions that we have examined than in the tigers, but the difference is very slight. 



The apparently sharper angle at which this process rises from the alveolar border in 

 the lion we find to be caused by the form of the anterior portion of the ramus in 

 that animal, which tapers slightly forwards through the length of the molar series, whUe 

 in Felis spelaa the alveolar and lower borders are nearly parallel (PI. I, figs. 1, 2, c d, ae). 

 The angle in both forms, F. spelaa and F. leo, is in reality as near as possible identical, 

 when measured with the alveolar border c d produced backwards, i. e. about 30° in each 

 case. But when the angle is measured from the lower border of the ramus a b, it is about 

 40° in the lion and 30° in Felis spelaa. This angle, however, is variable, and therefore 



