410 On neio Mammals from the Miocene of Baluchistan. 



and the last milk-tooth in his specimen being much smaller 

 and otherwise different from the first three-ridged tooth in 

 mine shows that the latter is a true molar, and the teeth 

 in front of it are true premolars and not milk-teeth. 



The lower-jaw fragments show in one specimen the last 

 premolar and the three molars, the last molar being in the 

 alveolus, fully formed and ready to come into wear ; it is 

 formed at a slanting angle to the future plane of wear, as 

 in all later Proboscidia. The other specimen shows only the 

 last premolar and the first two molars. 



Pilgrim* has suggested that the teeth described by 

 Lydekkerf from this locality as Tetrabelodon angustidens, 

 var. palceindicus, really belong to Hemimastodon. That this 

 surmise is correct is proved by the fact that the third lower 

 molar of the first jaw mentioned above is the same as the 

 tooth figured by Lydekker \ as belonging to the variety of 

 T. angustidens. 



The dentition of the genus therefore is : — 



I. C. PM. M. 



0. 2? . 0? .0? . 3 .4 1.2.3 

 0. 2? .0 0? .0? .3 .4 1.2.3' 



The shape of the symphysis is at present unknown, and 

 whether the anterior premolars were present or not cannot be 

 determined from these specimens. From the condition in 

 Palosomastodon it is reasonably certain that they were absent. 

 In Pakeomastodon all upper teeth from the second premolar 

 to the last molar and all lower teeth from the third premolar 

 onwards are in wear at once. In Hemimastodon the third and 

 fourth premolars above and below are much worn, and are 

 probably pushed out before the third molar is erupted, leaving 

 the three molars in wear. In Tttrabelodon § the second and 

 third premolars are cut in both jaws, but are entirely lost 

 before the second molar comes into wear. In all later forms 

 the premolar series is entirely suppressed. Hemimastodon, 

 therefore, is shown to occupy a place halfway between the 

 genera Palaiomastodon and Tetrabelodon, and, considering its 

 probable horizon, this is what we should expect. 



A further description and figures of these interesting 

 fragments will be published in a forthcoming catalogue of the 

 whole collection from the Bugti region. 



* Pal. Ind. n. s. vol. iv. memoir 2. 



f Pal. Ind. (10) vol. iii. pi. iv. fig. 3. 



t Trans. Roy. Soc. B. vol. 199, pp. 393-407. 



§ Trans. Roy. Soc. B. vol. 196, pp. 99-118. 





