MORRISON MAMMALS: PANTOTHERIA 45 



tidae. but he abandoned this in 1887, recognizing, as most subsequent writers have 

 failed to do, that there is no difference between this supposed family and the Dryo- 

 lestidae. 



In his memoir (i888a) Osborn recognized five families: Amphitheriidae, Pera- 

 lestidae. Kurtodontidae. Amblotheriidae, and Stylacodontidae. The first three were 

 placed with the Triconodontidae in the Prodidelphia as marsupials and the last two 

 in the Insectivora Primitiva as placentals. Later in the same year (i888b) he recog- 

 nized the unity of the Jurassic mammals with tritubercular molars as opposed to those 

 with triconodont molars and he abandoned the families Peralestidae and Kurtodonti- 

 dae. In 1893 Osborn consistently grouped these mammals together, calling them tri- 

 tuberculates. In the same year the name Trituberculata Osborn, as a taxonomic term 

 first appeared (Zittel 1893). 



Despite some rearrangement of their contents, the orders Pantotheria Marsh and 

 Trituberculata Osborn are synonymous. The question whether the prior term Panto- 

 theria or the more widely adopted Trituberculata should be used for the group has 

 been discussed in some detail elsewhere (Simpson 1928B, p. 108). It has been decided 

 that the earlier name is not open to serious objection and is less misleading. The order 

 is therefore called Pantotheria throughout the present work and its members panto- 

 theres. "Trituberculate" is understood to be a term in dental morphology, applicable 

 to members of various orders, and without taxonomic significance. 



Four more classifications of the group may be given in brief resume. That of 

 Osborn in 1907 is as follows: 



Infraclass Placentalia 



Order Pantotheria Marsh (Trituberculata Osborn) 

 Amphitheriidae 



Amblotheriidae or Stylacodontidae 

 Paurodontidae 

 Diplocynodontidae 

 Gregory 1910: 



Subclass Theria 



Infraclass Metatheria 



?Order Trituberculata (Pantotheria in part) 

 Amphitheriidae 



Amblotheriidae (Stylacodontidae) 

 Paurodontidae 

 Dicrocynodontidae (Doubtfully placed here) 



Gregory 1922: 



Order Trituberculata 

 Amphitheriidae 

 Stylodontidae 

 ? Diplocynodontidae 

 Schlosser in Zittel's Grundziige, 1923 edition: 

 Subclass Eplacentalia 



