EXTLXCT FAMILIES 



y -93 



Fro. 112.— A right 

 upper molar of Mi ry- 

 copotam " i pusillus, 

 Pliocene, India. 

 (From the Palceonto- 

 logia Indica.) 



and the feet have four digits. 



M< ri/mjiolininis. — The genus Mrryrojtotnmusoi the lower Pliocene 

 of India may he regarded as an Anthraeotheroid which has lost 

 the antero-median column to the upper molars 

 (Fig. 11-). so that these teeth are consequently 

 quadrituberculate ; and may thus he regarded as 

 typical examples of the hrachy-selenodont modifica- 

 tion of molar structure. 



Cotylopidce. — The Miocene genus Cot)jl<>p* (Ore- 

 oihm l ) is the type of a large American family in 

 which the upper molars are selenodont and usually 

 have four columns, while the lower canine is approxi- 

 mated to the incisors and its form and function 

 assumed by the first premolar. The last upper 

 premolar is simpler than the molars. There is no 

 flange to the angle of the mandible ; 

 The affinities of this peculiar family are probably widely spread, 

 but they may have been derived from the Anthracotheriidce. The 

 type genus has the full Eutherian dentition, but in some of the 

 more specialised forms (Cyclopidius) the upper incisors may be 

 wanting, and large vacuities occur in the lachrymal region. The 

 generalised genus Protoreodon, of the Upper or Uinta Eocene, has 

 rive cusps on the upper molars, arranged as in the Anthracotheriida . 

 The pollex is retained in the manus of the t}-pe genus. 



The family may be divided into subfamilies as follows : — 



I. Upper molars with four columns. 



1. Orbits open, no lachrymal fossa, a diastema, the last upper 



premolar with two outer columns, outer wall of upper 

 molars concave and inclined inwards. — Agriochosrince 

 (Agriochosrus). 



2. Orbits closed, a lachrymal fossa, no diastema, the last upper 



premolar with one outer column ; outer wall of upper 

 molars flattened. — Cotylopince (Cotylops, Eporeodon, Mery- 

 cochcerus, Cyclopidius, etc.) 

 II. Upper molars with five columns. — Protoreontince (Protoreodon). 



Anoplotheriidce. 



— This family in- 

 cludes several 

 Upper Eocene 

 European genera, 

 with selenodont 

 upper molars, 

 carrying five 

 columns arranged 

 as in Anthraco- 

 theriwm. One of 



Fie. 113. — Restoration of Anoplotherium con 

 (Upper Eocene). Cuvier. 



This name (Leidy, 1851) is preoccupied by Orodus (Agassiz, 1838). 



