

1G4 



DEVELOPMENT OF OKGANIC LIFE 



[Ch. IX. 



to a sub-class called Lyencephala, which comprises two orders 

 tlie Marsupialia and the Monotremata. In this last are in- 

 cluded the Echidna (or duckbilled Platypus) of Australia and 



same contir 

 mammalia 



membe 



remains 



this lowest 



fossil, but 



boniferous and other primary rocks, should air-breathers 



higher than the class of reptiles ever be discovered in theta, 



assuming that a thorough knowledge of the succession in 



time of the fossil vertebrata would bear out fully the theory 

 of progressive development f 



om 



sim 



complex types. We should then have monotremata in the 



m 



Tertiary strata, 



assuming 



undetermined 



In the history of the Tertiary and Post-tertiary series, it 



mammalia 



more 



perfect structures. Tor the 

 earliest known species of the placental sub-class does not 

 belong to the Quadrumanous order, the most ancient represen- 

 tative of that type being the Arctocyon primcevus, which has 



met 



in Prance in Eocene strata older than the 



Plastic clay or Woolwich beds. Of later date than this, M. 

 Rutimeyer has recognised, in a member of the Middle Eocene 

 group of the Swiss Jura, the jawbone of a monkey allied in 

 some points to the Mycetes or howling monkey of America 

 and in others to the Lemurs. If this determination be con- 

 firmed when more of the skeleton has been discovered, the 



would constitute the oldest known 

 Lrumanous animal.* The next step 



Coenopithecus lemuroides 



exam 



occurs in the Upper Miocene or Ealunian deposits of Europe, 

 in which several examples of the monkey tribe have been 

 met with, and among them some of the anthropomorphous 



apes 



One 



of them, the Dryopithecus, allied to the Grib- 



* The fossil monkey named Macacus nounced by the same anatomist in 1862, 

 Eocenus by Owen, found in 1840, at to be a pachyderm, more ample data for 



Kyson, near Ipswich in Suffolk, in a 



its correct determination having been 



stratum older than the London clay, and obtained. The very questionable authen- 

 which I formerly cited as quadrumanous ticity of another reputed British monkey 

 on the authority of Prof. Owen, was pro- will be alluded to (p. 194). 









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