MASTODON ARVEENENSIS. 43 



meridionalis and of M. (Tetralaph.) Arvemensis contained in 

 the Natural History Museum at Florence, and was satisfied 

 that it belonged to the latter species, as Cuvier had inferred 

 from the drawing. The same Museum contains the greater 

 part of a skeleton of Mastodon, found in a marine deposit of 

 the lower Val d'Arno above Leghorn. The lower jaw of this 

 specimen presents the same character of a short symphysial 

 beak without incisors. The same is exhibited by the lower 

 jaw of the Dusino skeleton from the Astesan, described by 

 Prof. Eugenio Sismonda. 1 They all agree in the common 

 characters, so far as these are shown, of a Tetralophodon 

 formula to the crown ridges of the three molars here called 

 intermediate ; of alternate mammillse to the ridges with 

 blocked-up valleys; and of a short obtuse beak with no 

 incisors. 



Sismonda describes and figures the lower jaw of the Dusino 

 specimen as being without tusks, or remains of their sockets. 

 But, predisposed to believe that they must have been present 

 at some period of the animal's existence, from their occur- 

 rence in other Mastodons, he conjectures that those tusks had 

 fallen out early, and that the alveoli had been obliterated by 

 filling up ; and he has given a representation of a very muti- 

 lated fragment of a Proboscidean symphysis of the lower jaw 

 as exhibiting the alveoli of two mandibular incisors. 2 I was 

 enabled, by the obliging kindness of Signor Bartolomeo 

 Grastaldi of Turin, to examine the specimen in question, which 

 is very much rolled, and in a different mineral condition from 

 the fossils of the Dusino Mastodon bed, and found that the sup- 

 posed incisive alveoli were only the anterior terminations of the 

 dentary canals, which are of large size in all the Proboscidea. 

 The form impressed me with the conviction that it was more 

 probably the symphysis of an Elephant than of a Mastodon. 

 This case, therefore, gives no support to the belief that M. 

 (Tetralophodon) Arvemensis had lower incisors. 



Professor Owen, in his ' British Fossil Mammalia,' gives a 

 very beautiful representation (p. 291, fig. 101) of a fragment 

 of a tusk discovered by Mr. Fitch in the Mammaliferous Crag- 

 pits near Norwich. He describes it as a portion of the lower 

 tusk of the Mastodon angustidens. The specimen is about 15 

 inches long, with a greatest diameter of 3 inches. It is of 

 a straight, compressed, conical form. The fragment is 

 crushed, and it is manifest that the outer layers of the ivory 

 are detached, and that the original tusk was of a laro-er 

 diameter than the specimen now exhibits. The marked 

 conical form and great size are irreconcileable with this 



1 Osteograph. di un Mastod. angustidente, tab. i. fig. 1 . 



2 Op. cit. tab. i. fig. 7. 



