KAJJTODOff. 



KA8TODOV. 



Molu Tool! 



iligbtly worn. 



But when from longer use the conical teat-like point* are me ro deeply 

 worn down, the following appearance in presented : 



Molar Tooth of Mutodon, a good deal worn, seen from above. 



The war in which these teeth are let in the upper jaw will be seen 

 from the following cut : 



Molar Teeth and Palate of Mastodon. 



Awl the mode in which those of the lower jaw are arranged will be 

 perceived from the figures gi/eu below. 



1'orti'ini of Lower Jaw of Mutodon. 



Th general contour of the lower jaw as viewed from above may 

 M collected from the following figure. 



Portion of Lower Jaw of Mastodon. 



In his ' British Fossil Mammals' Professor Owon makes the follow- 

 ing prefatory remarks to his description of these teeth : 



" Naturalists are most familiar with that gigantic type of quadrupeds 

 called, from the peculiar prehensile development of the nose and 

 upper lip ' proboscidian,' as it is manifested by the existing species of 

 Elephants, which have been at different times introduced into Europe 

 from the tropical regions of Asia and Africa ; and we have seen in the 

 preceding section that an extinct species of this genus once ranged 

 over the whole of the temperate and part of the arctic zones of the 

 northern hemisphere of the globe, and has left abundant evidence of 

 its former existence in our island. In like manner we learn from the 

 study of fossil remains that other quadrupeds as gigantic as Elephants, 

 armed with two as enormous tusks projecting from the upper jaw, 

 and provided with a proboscis, once trod the earth ; the presence of the 

 latter flexible organ being inferred not only by its necessary co-exist- 

 ence with long tusks, which must have prevented the mouth reaching 

 the ground, but also by the configuration of the skull, by the holes 

 which gave passage to large nerves, and by depressions for the attach- 

 ment of particular muscles analogous to those which relate exclusively 

 to the organisation of the trunk of the Elephant. Like the Elephant 

 also, these other huge proboscidian quadrupeds were destitute of 

 canine teeth, and provided with a small number of large and complex 

 molar teeth successively developed from before backwards in the jaws, 

 with a progressive increase of size and complexity from the first to the 

 last The broad crowns of the molar teeth are also cleft by transverse 

 fissures; but these clefts were fewer in number, of less depth, and 

 greater width than the Elephants ; the transverse ridges were more or 

 less deeply bisected, and the divisions more or less produced in the form 

 of udder-shaped cones, whence the name Mastodon assigned by C'uvirr 

 to the great proboscidian quadrupeds of this kind. A more important 

 difference presents itself when the teeth of the typical species of 

 Mastodon are compared with those of the Elephant in reference to 

 their structure. The dentine, or principal substance of the crown of 

 the tooth, is covered by a very thick coat of dense and brittle enamel ; 

 a thin coat of cement is continued from the fangs upon the crown of 

 the tooth, but this third substance docs not fill up the interspaces of 

 the divisions of the crown, as in the Elephant Such at least is the 

 character of the molar teeth of the first discovered species of Mastodon, 

 which C'uvier has termed Mat/odon yigantetu, and Jf. anyuttident. 

 Fossil remains of proboscidians have subsequently been discovered 

 principally in the tertiary deposits of Asia, in which the number and 

 depth of the clefts of the crown of the molar teeth, and the thickness 

 of the intervening cement, are so much increased as to establish 

 transitional characters between the lamello-tuberculate teeth of the 

 Elephant and the mammillated molars of the typical Mastodon, 

 showing that the characters deducible from the molar teeth are rather 

 the distinguishing marks of species than of genera in the gigantic 

 proboscidian family of mammalian quadrupeds. 



" Two dental characters however exist, though hitherto I believe 

 unnoticed as such, which distinguish in a well marked and unequivocal 

 manner the genus MaitoJon from the genus Elephat. The first is too 

 presence of two tusks in the lower jaw of both sexes of the Mastodon, 

 one or both of which are retained in the male, and acquire a suffi- 

 ciently conspicuous size, though small in proportion to the upper 

 lusks; while both are early shed in the female. The second character 

 .a equally decisive ; it is the displacement of the first and second molars 

 n the vertical direction, by a tooth of a simpler form than the second, 

 developed above the deciduous teeth iii the upper jaw, and below them 

 u the under jaw. These two dental characters, which are of greater 

 mportnce than many accepted by modern zoologists as sufficient 

 lemarcations of existing generic groups of Mammalia, have been 

 ecognised in the species called Mattodon giganteui, most common in 

 S'orth America, and in the Mcutodon anyuitiili.ni, which in the prevailing 

 species of Europe. 



" To the last named species I refer the comparatively few remains 

 of the Mastodon that have been discovered in England, and hitherto 

 exclusively in these deposits, consisting of sand, shingle, loam, and 

 animated clay, containing an intermixture of the shells of terrestrial, 

 resh-watcr, and marine Mollutca, which extend along the coast of 

 Suffolk and Norfolk, and have been no admirably described by Mr. Lyell 

 under the name of the Fluvio-Marine C'rag, and referred to the Older 

 ,'lioccne division of his tertiary system." 



