294 Note on the teeth of the [May, 



VIII. — Note on the Teeth of the Mastodon a dents etroites of the Siwdlik 

 Hills. By Captain P. T. Cautley. PL XL 

 [Read at the meeting of the 1st June.] 



Without further preface I refer the reader to the 1 st volume of the 

 Osemens fossiles, page 268. Figures 1 and 2, plate 4, under the head 

 of " Divers Mastodons." 



These drawings were presented to Cdvier by M. Faujas, and the 

 fossil was found near Asti in Upper Italy. 



Cuvier merely alludes to this fossil as one of the varieties into which 

 the true Mastodon a dents etroites passes by a greater subdivision and 

 an irregularity of position of the mamilla? ; the proportions of length 

 to breadth of the tooth retaining their full and perfect character. 



By comparing the accompanying drawings with the figures above 

 alluded to, there can be no demur, I imagine, in identifying the Siwalik 

 variety of Mastodon now under review with the Asti fossil. It remains 

 therefore simply to note the peculiarities in form of the tooth : al- 

 though it may be a point of consideration hereafter, whether, as the 

 character of the tooth is so marked, and its peculiarities so rigidly 

 adhered to throughout the whole of the remains found in the Siwaliks, 

 it may not be placed under a sub-genus, that of " angustidens," with 

 the specific denomination of M. Sivalensis. 



There is no cortical substance or crusta petrosa ; the tooth consist- 

 ing of enamel and ivory only, the former being very thick and mas- 

 sive, as is normal in the mastodons. 



The coronal surface consists of a double line of conical and obtusely 

 pointed mamilhe : those on the external side being in most cases per- 

 fect, whilst those on the inner side are divided by a fissure or fissures 

 into two or three irregulai'ly formed obtuse points. These mamillae 

 are not, as in the true Mastodon angustidens, placed transversely or at 

 right angles with the line of surface, but meet each other from right 

 to left alternately, so that the furrow on one side is interrupted by 

 the mamilla on the other ; and the mamillee on the whole line of tooth 

 lock into each other in the same way that two serrated edges opposed 

 to each other might be supposed to do, were they placed in contact. 



The outer surface of the enamel is smooth, and the space or furrow 

 between each mamilla both on the external and internal surface is 

 marked by a small tubercle, the presence of which however does not 

 appear to be constant. 



The surface of the tooth of the lower jaw wears obliquely and out- 

 wardly on the grinding surface, as in the ruminants, in which respect 

 it differs entirely from the elephants. 



The wear of the coronals is marked at the commencement by irre- 

 gularly lobed figures, which, as the detrition advances, become confus- 



