46 PLEISTOCENE MAMMALIA. 



§ 9. Intermaxillary (Pis. VI, VII, VIII, X, XI, No. 2.2).— The inter- or pre- 

 maxillaries form the anterior end of the face, and consist, like the maxillaries, of an ascend- 

 ing and an horizontal process. The first of these, which may be called the nasal process, is 

 wedged in between the maxillary bone below and the nasal above, forming part of the lower 

 portion of the alveolus of the canine, and is to a great extent overlapped by those two 

 bones. The horizontal, incisive, or palatal process is articulated behind to the palatine 

 process of the maxillary, and in the. median line to its fellow by a straight symphysis, 

 strengthened by a ridge on the superior or nasal surface, which with its fellow ridge forms 

 a trough, which is articulated to and forms a continuation of the vomer. The palatine 

 suture is interrupted by the two large oval naso-palatine foramina {k), which open 

 into two grooves that pass forwards as far as the inner edge of the incisive border. 

 The incisive border in front forms an arc of a large circle, and is separated from the 

 alveolus of the canine by a shallow excavation for the reception of the canine of the lower 

 jaw. 



The intermaxillary bones form the lower and lateral boundaries of the nostrils, and 

 present us with a character of specific value^ by which we can separate lion from tiger. 

 In viewing the lower half of the nasal aperture in front, its inner bounding line takes the 

 form of an even curve, expanding regularly in the former animal, while in the latter it is 

 distinctly a surface of double curvature. This character is more strongly impressed on 

 the larger than the smaller skulls. In Felis spelaa it is strongly marked, and its 

 evidence as to the leonine character of that animal is beyond doubt. The Sundwig skull, 

 however, is somewhat exceptional, showing a tendency towards the double curvature of 

 tiger, but the tendency is not greater than that presented by several small skulls of lion. 

 The nasal, or ascending, is inclined backwards at an angle of from 50° to 60° with the 

 horizontal process in Leo, Tigris, and Fells s^pelcea, the angle being greatest in the largest 

 skulls. 



Muscles. — The myrtiform^ muscle for the dilation of the nostril, and the moustache 

 muscle for the protrusion of the lip, take their origin from this bone ; the one from the 

 sides of the nasal aperture, and the other from the median suture. 



§ 10. Petrosal; Mastoid; Tympanic (Pis. VI, VIII, IX, Nos. 16, 8, 28).— 

 In the description of these bones we adopt Professor Owen's numbers and nomen- 

 clature, without committing ourselves to his views of their homologies, rather than 

 enter into a discussion which has no immediate bearing on our present work. 

 We shall therefore describe the petrous bone, together with the posterior descending 

 process, as the petro-mastoid, and the remainder of the acoustic organ as the tym- 

 panic. 



1 This difference is pointed out by M. de Blainville, ' Ost. Felis,' p. 28. 

 - Straus-Durckheim, op. cit., vol, ii, pp. 208, 209. 



