1881.] 379 ; [Cope. 
The genera included in these families are the following. The table 
shows their geological distribution : 
EOCENE, MIOCENE, 
Lower| Upper Lower! Middle Upper 
| PLIOCENE, 
RECENT, 
Lophiodontide. 
Hyracotherium Ow. .............. 000: 12 
Pliolophus Ow. .......... ec ccc cece eee 4 
? Lophiotherium Gerv..............04- 
Pachynolophus Pom. ..........-...005 3° 
Helaletes Marsh............ 0.0.0 ee eee 
Lophiodon Cuv........ 0... cece eee eee 2{|1 
Hyrachyus Leidy...-..............00. 
Colonoceras Marsh............-...008 
Rom COCR Ww 
Triplopida. 
Triplopus Cope............. cece eevee 2 
HAyracodontida. 
Hyracodon Leidy. .............000eees 2 
Rhinocerontida. 
Aceratherium Kaup.................5. 3 
Coenopus Cope. ..... see eeeeeeeee eee 2 
Diceratherium Marsh................. 3 
Falabis COPes ss .ivcaes cassigiionwas geen 
Aphelops Cope........... cess eeeeeeees 
Ceratorhinus Gray.......... 0002s eee eee 1 
Rhinocerus Linn................2..05- 
Peraceras Copeé.......-. see eee cece ee 
Atelodus Pom..............c eee e eee 
Ww we 
a 
Q 
8, 
° 
a 
° 
B 
a 
2 
w 
8 
° 
5 
2 
Oo 
Tapiride. 
Listriodon Gerv.... ....ceeeeeeeeeeee 23 
Pa pirus: DUN. i.3¢ casas sas odors See 4985 6 
Elasmognathus Gill......cseeeeeeeeces 
eo 
Chalicothertida. 
Rhagatherium Pict...........00..ee0-- 1 
Leurocephalus 8. 8. and O.... .....-.. 
Paleeosyops Leidy.........-.seeeeeeees 1 
Limnohyus Leidy............0-ee eee 
Lambdotherium Cope..........+.+e+5+ 2 
Propaleotherium Gerv........--++-+-- 1 
Chalicotherium Kaup. ... 
Nestoritherium Kaup...........+.+e00- 1 
Meniscotherium Cope........+.++-+06 1 
Wwmrwawr 
Macraucheniide. 
Macrauchenia Ow...... Sa awareness’ 2 
PROC, AMER. PHILOS. soc. xrx. 108. 2v. PRINTED May 14, 1881. 
