34 



BEITISH AND EUKOPEAN FOSSIL MASTODONS. 



much narrower than the base. Two large outlying mammillse 

 are interposed between the first and second ridges, one 

 between the second and third, and one between the third and 

 fourth. A large tubercle, flanking the inner division of the 

 first ridge, forms the commencement of the anterior talon. 

 The posterior talon consists of a line of about six low tuber- 

 cles. The intermediate flanking mammillae, as is usual in 

 the species, interrupt the transverse continuity of the valleys, 

 which are reduced to an outer and inner gorge. It is mani- 

 fest that, if the crown were ground down by wear, the dis- 

 position of the tubercles is such that a series of trefoil discs, 

 more or less alternate, would be the result. The dimensions 

 of this specimen are — length 4*9 inches, width of crown in 

 front 2*6 inches, width at the last ridge 2-9 inches. 



Premolars. — That vertically successional teeth replace one 

 or more of the milk molars in M. (Tetraloph.) Arvernensis 

 has been proved by the original specimens from Auvergne', 

 upon which the species was founded by Croizet and Jobert. 

 Fig. 7 of PI. XI. of their work ' exhibits an upper jaw of a 

 very young animal, containing the antepenultimate and penul- 

 timate milk molars in situ, the former consisting of two pairs 

 of points, disposed in two ridges, the latter showing three 

 ridges. Behind the second tooth there is introduced, in the 

 figure above referred to, a germ-fragment consisting of two 

 ridges (marked A), as if of the third milk molar ; but Abbe 

 Croizet states, in the descriptive details, that the fragment 

 was found detached, and that for various reasons, which are 

 detailed, he considers it to be incorrectly placed in the figure. 

 In the original specimen, which I had an opportunity of 

 examining at Paris, the remains of part of the alveolus of a 

 vertical premolar were distinctly visible above the penulti- 

 mate milk molar ; and M. Latirillard informed me that he 

 had seen the germ of this premolar, the tooth ' A ' above re- 

 ferred to being the one in question, i.e. the penultimate pre- 

 molar. The last premolar, which is the vertical successor of 

 the last milk molar, has not as yet been observed in situ, so 

 far as I have had the means of ascertaining. 



No premolars of the Crag Mastodon, from English locali- 

 ties, have either been figured or described in the ' British 

 Fossil Mammalia,' or elsewhere, up to the present time. 2 This 

 is of little moment, in so far as the mere identification of the 

 species is concerned. Premolar specimens may probably be 

 found either in Mr. Pitch's or in some other of the Norfolk 

 collections. 



1 Oss. Fossiles du Depart, du Puy-de- 

 Dome, pp.134, 135. 



* The specimen referred to by Mr. 



Fitch, as cited in the ' British Fossil 

 Mammalia,' p. 290, is not a premolar of 

 the Crag Mastodon. 



