290 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



(Loxodon) planifrons and E. (Loxodon) meridionalis, I instituted a 

 close search in the latter for the premolar teeth, which are so 

 remarkably developed in the former ; but I could detect no indication 

 of their presence. 



f. Bidge-fonnidce. — Taking the data yielded by the preceding 

 descriptions, and using x as a symbol for the talons, the " ridge- 

 formula " of the true molars in E. (Loxodon) meridionalis appears 

 to be thus ; — 



x8x-\-x(8-9)x-xlS.v 

 a;8.v+x{S-9)x+{Vd-15yx ' 

 and for the whole series, milk and permanent, rejecting talons, 



Milk-molars. True molars. 



3 + 6 + 8, 8 + (8-9) + 13 



3+6 + B' 8 + (8-9) + 13-15 



If this is compared with the " ridge-formula " of E. (Loxodo7i) 

 Africanus and E. (Loxodon) jylanifrons {anted,, pp. 265 & 266), it 

 will at once be perceived that they agree in the hypisomerous cha- 

 racter of the intermediate molars, here indicated as distinctive of 

 the group from Euelephas — the obvious difference being that, be- 

 sides a greater number of plates in the last true molars, upper and 

 lower, the cipher 8 prevails in E. meridionalis and the cipher 7 in 

 the others. In order to show how essentially distinct the Italian 

 fossil species is in its molars from E. (EuelepJias) primigenius, I 

 may anticipate the results to be found in the sequel, so far as to 

 contrast the ridge-formula of the true Mammoth, viz. : — 



Milk-molars. True molars. 



4 + 8 + 12. 12 + (16-18) + 24 



4+8 + 12' 12 + (16-18) + 24-27" 



For the manner in which this difference operates in modifying the 

 form and relative proportions of the alternate layers of ivory, 

 enamel, and cement, I may refer to the longitudinal and vertical 

 sections of the molars, represented in fig. 1 of pi. 1, and fig. 5, pi, 2, 

 of the ' Fauna Antiqua Sivalensis,' the former being of the Mam- 

 moth, the latter of E. (Loxodon) planifrons, in which the section 

 closely resembles that of E. {Loxodon) meridionalis. 



g. Characters of the TusTcs. — In some of the crania the tusks are 

 preserved entire; and the specimens are sufiiciently abundant to 

 furnish a correct idea of their form and direction. In one cranial 

 fragment, comprising the united incisive bones, they are finely pre- 

 served in their natural position. In this case, the extruded portions 

 diverge for some littledistance in a straight line; they are then directed 

 outwards, and curve gradually upwards and inwards, so that the 

 points are closely approximated. 'VMien this incisive fragment is ' 

 placed erect, the included area (between the tusks) gives a trun- 

 cate, ovate, or lyrate outline, with the point towards the tips. 

 Viewed sidewise, they apjjear to be produced forwards and upwards 

 in a very gentle curve. On the whole, thej' do not differ much in 

 this instance from varieties seen in the existing Indian Elephant. 



