MARSUPIALIA. 



409 



to state this with absolute certainty. The oldest known 

 European Mammal is the Microlestes antiquus of the Upper 

 Trias, only a few teeth of which have been as yet detected. 

 The earliest horizon on which Microlestes occurs is in a " bone- 

 bed " in the Keuper of Wiirtemberg ; but it has also been 

 detected in the higher " Rhaetic " beds. Professor Owen 

 believes that the Hypsiprymnopsis of Mr Boyd Dawkins, from 

 the Rhaetic marls of Somersetshire, is also referable to Micro- 

 lestes. Upon the whole, it is most probable that Microlestes 

 was Marsupial ; and it appears to be most nearly related to 

 the little insectivorous Myrmecobius or Banded Ant-eater of 

 New South Wales (fig. 337). 



Fig. 337. Myrmecobius fascia ins. 



Nearly allied to Microlestes is a small Mammal, a lower jaw 

 of which has been obtained from the Trias of North America, 

 and which has been described under the name of Dromatherium 

 sylvestre. This little animal (fig. 338) appears also to be Mar- 

 supial, and to be most nearly related to Myrmecobius. Each 



F 'g- 338. Lower jaw of Dromatherinnt sylvestre (after Emmons). From rocks 

 supposed to be of Triassic age, in North Carolina. 



ramus of the lower jaw contains " ten small molars in a con- 

 tinuous series, one canine, and three conical incisors the 

 latter being divided by short intervals " (Owen). 



