REPORT ON THE EXPLORATION OE BRIXHAM CAVE. 
545 
same species, intermixed with a few of a larger size and several of a smaller, it will be 
interesting to inquire whether these conclusions are borne out by the forms of the more 
characteristic teeth. The most distinctive of these are, in the lower jaw, pm 4 and m 3, 
and in the upper, pm 4 and m 2. In his very careful description of the Manea Fen 
jaw. Professor Owen * notices that the lower last premolar in TJ. spelceus has “ two 
distinct tubercles and a ridge developed from the base of the principal cone,” whilst in 
the Manea-Fen jaw there was only the single cone, as in TJ. circtos. Subsequently, in 
speaking of TJ. prisms, he remarks that the same tooth also presents a second cusp on 
the inner side and a little behind the first. Now these characters appear to me to be 
very constant and of the utmost possible value. There can be no doubt, so far as I have 
seen, that in the true TJ. spelceus the last lower premolar has usually two cusps, and always 
one very distinct and, in some cases, a very large secondary cusp on the inner side, one 
of which is in front of the principal cone, and by which, irrespective of its size, that 
tooth may always be distinguished. In the typical specimen of TJ. priscus in the British 
Museum the last premolar, at any rate on the right side, of which I have a cast before me, 
has but an extremely faint indication of a second cusp, or rather tubercle, as it should be 
called in this species ; but as the teeth in this specimen are much worn, the indistinctness 
may be owing to that circumstance. In a jaw of undoubted TJ. prisms from Gower a 
tubercular elevation is very distinctly situated also on the inner side of the tooth, but alto- 
gether behind the main cone ; whilst in several of the Brixham teeth the small accessory 
tubercle in the same position is extremely well shown. In the only specimen of TJ. 
ferox in which I have had an opportunity of making the observation, the last premolar 
presents a distinct tubercle in the same situation, and the hinder talon, as it may be 
termed, is bitubercular. The next characteristic tooth in the lower jaw is the last 
molar. In TJ. spelceus this tooth, though varying, as is shown in the table, considerably 
in size, always presents more or less completely an oblong or quadrangular form with a 
deep sinus on the outer side, whilst in TJ. prisms it is always more or less triangular, 
and either not at all or very slightly notched on the outer border. It presents, so far as 
I have seen, the same general form in TJ. ferox and TJ. circtos ; and it would in many 
cases be impossible, I imagine, to distinguish between these three species with respect to 
the shape of this tooth. There are five specimens of the last lower molar in the Brixham 
Collection, two considerably worn, the others very perfect. In all its shape is triangular, 
and altogether different from that presented by it in any specimen of TJ. spelceus that has 
come under my observation. One of the largest and smallest of these teeth are shown in 
figs. 5 & 6, Plate XLVI. The smaller may, and I believe does, belong to TJ. circtos, and I 
have no hesitation in referring the other to TJ. prisms. 
In the upper jaw the differences in size are perhaps even more strongly marked than 
in the lower teeth ; but, as regards their form, they appear to be less constant, and to 
* Brit. Foss. Mammals, p. 80. (It would be very desirable to have the measurements of all the teeth in this 
specimen.) 
4 D 2 
