258 



SUBUNGULATA 



ORDER IX 



and have a persistent pulp-cavity. P^ and Pg have only one cusp with a small 

 protuberance. P^ with large outer and small inner cusps. P^ of the upper 

 and lower jaws has four paired cusps. Molars as in Teirahelodon and Mastodon, 

 each have three well-defined transverse ridges consisting of two cusps each. 

 M^ usually with a talonid. Symphysis of the lower jaw very much elongated. 

 Narial openings high and rather remote. Skull rather high and short, 

 pavietals slightly convex, and having a sagittal crest. Oligocene of Egypt. 



P. beadnelli Andrews 

 must have had a fairly 

 long proboscis. 



Eemimastodoii Pil- 

 grim. Teeth inter- 

 mediate between those 

 of Palaeomastodon and 

 Mastodon. Lower 



Miocene, India. 



Tetvabelodon Cope 

 (Figs. 342-345). Skull 

 more resembling that of 

 Elephas but the frontals 

 are less steeply inclined 

 upward. Upper jaw 

 lower, symphysis of 

 mandible much elon- 

 gated. Skeleton less 

 elevated and 



Fig. 340. 



Palaeomastodon beadnelli Andrews. Oligocene, Fayum, Egypt, 

 and lower jaw restored, i/io- (After Andrews.) 



Skull 



robust. 



formula : 



Superior 

 straight 



more 



Dental 



1.0.3-0.3. 



1.02-0.3. ■ 



incisors 



slightly 



Palaeomastodon sp. 



Oligocene, Faynm, Egypt. J , Upper cheek teeth. 

 B, Lower cheek teeth. 1/3. 



curved downward, with 

 a broad external band 

 of enamel. Inferior 

 incisors smaller and 

 shorter than the upper, 

 forming a spatulate end to the jaw. Superior cheek teeth large, oblong, 

 quadrate, with three, four, more rarely five high transverse crests, either 

 simple {Zygolophodon) or broken up into mammiform bosses (Bunolophodon) 

 separated from each other by deep valleys. A median groove divides 

 each transverse crest into two halves and also runs longitudinally through 

 the entire length of the crown. The whole crown of the tooth is coated 

 with a thick layer of enamel; the cement is. also exceptionally developed, 

 yet never entirely fills the transverse valleys. The crowns of the superior 

 cheek teeth are inclined from without inward, and the wear by means of 

 which the dentine is laid bare is stronger on the internal than on the external 

 half of the tooth. The inferior cheek teeth differ from those above merely 

 in their somewhat narrower breadth, the undiAnded transverse roots beneath 

 the crests, the oblique inclination from without inward, and the stronger 

 wear on the outer half of the crown. 



