128 



SKETCH OF THE HISTORY OF MAMMALIA. 



lower jaw ; J, crown of the two anterior molar teeth of 

 the lower jaw, enlarged ; e, crowns of the two posterior 

 molar teeth of the upper jaw, enlarg-ed. 



# f 



Skull of Ciivier"s Lagotis 



The Viscacha or Biscacha of the Pampas 



{Lagostomus trt/chadacti/liis, Brookes ; the Marmot Diana 

 of Griffith). 



Generic characters : — the molars consist of two ob- 

 lique lamellee, excepting the posterior one in the upper 

 jaw, which consists of three ; anterior feet with only 

 four toes, hinder feet with only three ; tail moderate. 

 Of this genus (Lagostonnis) we know but one species, 

 of which the earliest notice to be found is in DobrizhofFer's 

 ' Historia de Abiponibus,' 1784. He informs us that it 

 is called by these people Nehelaterek, and that it re- 

 sembles a hare with the tail of a fox. (Fig, 83.) " It 

 digs its burrows on the more elevated parts of the plains 

 with so much art, that no aperture is left by which the 

 rain can penetrate, and these burrows are divided into 

 distinct settlements, numerous families inhabiting the 

 same locality. On the surface of the ground are several 

 entrances into the burrow, at which, towards sunset, the 

 animals may be seen seated in crowds, diligently listen- 

 ing for the sound of any person approaching. If every- 

 thing remains quiet, they venture forth by moonlight to 

 feed ; and commit sad havoc on the neighbouring Helds, 



