Cranial Variations in the Scotch Wild Cat. 273 
in others it is equally constantly absent; in others it may be 
absent or present within the limits of the same species. 
When present it is, except in the case of F. planiceps, a 
small or very small tooth, reduced in size to give depth to 
the penetration of the upper canine, and is probably funetion- 
less or nearly so. 
The suppression of pm? of the lower jaw to give depth to 
the penetration of the lower canine has been carried a stage 
further—almost, indeed, to completion,—only a compara- 
tively few instances of its presence having been observed. 
The reduction in size or suppression “of these premolars 
leaves primarily a longish postcanine diastema; and the 
depth of this is frequently increased by the emargination of 
the alveolar border which formerly carried the teeth, and not 
infrequently by the elevation of the anterior portion of the 
mandible carrying the canines and incisors. ‘The presence 
of this diastema must, I think, be regarded as a primitive 
feature. Hence its suppression by the shortening of the 
jaws resulting in juxtaposition between the canines and the 
first large premolars (pm’*) above and below, such as has 
taken place in Acinonyx (Cynailurus), must be interpreted as 
a derivative feature. 
In Bateson’s ‘ Materials for the Study of Variation,’ 
pp. 223-224 (1894), there are records of the presence of an 
additional anterior upper premolar on one or both sides in an 
example of F. pardus, F’. eyra, of F. sylvestris, quoted as catus, 
from Athens, and of several domestic cats, quoted as domes- 
tica and caligata. Also there are records of an additional 
anterior lower premolar on one or both sides in an example of 
Ff. concolor, of F. sylvestris or ocreata, of F. sylvestris, and 
of a few domestic cats. To these must be added a reference, 
overlooked by Bateson, to the occurrence of the extra lower 
premolar in an example of /. tigri’s (Lydekker, J. A. 5. 
Bengal, xlvii. pt. 2, pp. 2-3, pl. i1., 1878). 
In a series of elevén skulls of F. sylvestris, all from 
Inverness-shire or Ross-shire, in my possession, no fewer 
than four—that is to say, over 33 per cent.—have an addi- 
tional anterior lower premolar, three showing it on both sides 
and one on the right side only; and in one skull of the 
former category of three there is an additional anterior upper 
premolar on the left side. 
In all the skulls of other species of Felide belonging to 
the Zoological Society, only one has an extra premolar— 
namely, a skull of #. wiedi (macrura),—which exhibits it 
on the left side above. ‘The rest, of which in some cases 
there are tolerably large series—7. ¢., eleven of /. pardus, 
