ABSTRACTS OF PAPERS 135 



IcL Longirostral, long- jawed, bunomastodonts, 

 Africa, Eurasia, America, 



16. Rhynchotherine, beak-jawed, bunomasto- 

 donts, North America. 



Ic. Brevirostral, short-jawed, bunomastodonts, 

 Asia, America. 

 B. Zygolophodont : 



2. Mastodontincc, typical mastodonts of Europe, x\sia, 



America. 

 III. Elephantidw: 

 STEGODONTS. C. Brachylophodont, short-crowned, crested teeth. 



3. Stegodontinw, stegodonts of southern Asia. 

 ELEPHANTS. D. Hypsilophodont, long-crowned, crested teeth. 



4. Loxodontince : 



4a. Loxodonta antiquus, straight-tusked ele- 

 phants, Eurasia, Africa. 

 46. Loxodonta africanus, African elephants. 



5. Elephanthue: 



5a. EnelepJias primipenins,msimm6ths, Eurasia, 

 North America 



56. Euelephas columM; E. imperator, Ameri- 

 can mammoths. 



5c. Elephas indicus, Indian elephants. 



The three traditional families, namely, the Dinotheriidw, Mastodontidce, and 

 Elephantidw, call for no comment. 



The mastodonts may be divided into two subfamilies, namely, (1) the Biino- 

 fnas'fodontinw, which are clearly distinguished by the presence of cones grow- 

 ing in between the transverse crests and forming "trefoils," to use the term 

 introduced by Cuvier in his description of the grinding teeth of M. angustidens. 

 This was the first bunomastodont discovered and is the type of a great race 

 of longirostral, long-jawed, short-limbed forms, which ranged widely from 

 northern Africa over Europe, Asia, and North America. As shown also in the 

 accompanying scheme, the bunomastodonts, which sprang from Palwomastodon 

 of the Oligocene of northern Africa and possibly as well from Hemimastodon 

 of southern Asia, divide into three great, long-lived phyla, which may be dis- 

 tinguished as follows : 



Longirostral, long-jawed, typified by the species M. angustidens. 



Medirostral, beak-jawed, typified by Rhynchotherium. 



Brevirostral, short-jawed,- typified by the species M. mirificus. 



The long-jawed and short-jawed phyla of bunomastodonts. are comparatively 

 well known in Europe, Asia. North and South America. The beak-jawed 

 phylum, typified by the genus and species Rhynchotherium tlaxcalw,^ is pro- 

 visionally arranged, because there is some uncertainty as to the position of 

 the species R. euhypodon Cope, R. (?) shepardi Leidy, and R. hrevidcns Cope. 

 The rhynchotherines are readily distinguished by jaws of medium length, which 

 tend to turn downward into a long, depressed beak, somewhat like that of 



8 The specific name tlaxcalw is suggested to llie author by Dr. AV. D. Matthew in refer- 

 ence to the locality in Mexico, Tlascala. 



XI — Bull. Geol. See. Am., Vol. 29, 1917 



