312 Bulletin American Museum of Natural Hif<tory. [Vol. XXVII, 



(3) The dentition of the Oxyclseniclse (represented by Tricentes, Chria- 

 cus, etc.) is structurally more or less prototypal to that of both groups. The 

 Mesonychid type may be derived from it by way of Triisodon . The Oxypenid 

 and Hysenodont dentitions, however, even in their most primitive known 

 stages have already advanced far beyond it. The Arctocyonid and Miacid 

 dentitions, while divergently specialized, present no features incapable of 

 derivation from the Oxyclsenid type. 



The derivation of these various lines of Creodonts and ancestral Fissi- 

 pedes will not be settled until more intermediate stages, as well as the skull 

 structure of the Oxyclsenids, shall be discovered; however the Oxyclrenid 

 dentition is intermediate in character between the various Carnivorous 

 dentitions on the one hand and the simple Insectivore type represented in 

 Ictops and Pantolestes on the other. If the Oxyclsenidte should be proved 

 to be allied to the ancestral Lipotyphla and thus to fall within the definition 

 of the order Insectivora, it will follow that the various lines of Creodonts and 

 the ancestral stem of the Fissipedia have been derived independently from 

 an "Insectivore-Creodont" stock of possibly Upper Cretaceous age. 



11. The Pinnipedia. 



Outline histonj of the ordinal classification. 



1693. Ray includes "Phoca" and the walrus (" Morse") with the other 

 Carnivora in the "Quadrupeda vivipara unguiculata, mviltifida, carnivora 

 majora capite longiore." 



1735-1766. Linnaeus includes Phoca in the order Ferae. 



1780. Storr assigns the seals to the Phalanx Pinnipedia, one of his three 

 primary divisions of the Mammalia. 



1779-1797. Blumenbach proposes the order Palmata to include {A) 

 Palmata Glires, {B) Palmata Ferae (Phoca, Lutra), (C) Palmata Bruta. 



1795. Geoff roy and Cuvier apparently follow Blumenbach in placing 

 Phoca and Rosmarus with Manafus, Trichechus (the Dugong) in "les Amphi- 

 bies," an old group which had been very properly broken up by Linnaeus. 



1800. Cuvier restricts "les Amphibies" to include only "les Phoques" 

 and "les Morses," and places the order next to "les Cetaces" in a grand 

 division "a ])ieds en nagoire" of the Mammalia. 



1811. Illiger uses Storr's term Pinnipedia both as an order and as a 

 "familia." 



1816. De Blainville groups "Les Phocpies," "les Taupes," and "les 

 Cheiropteres" as a grand division "anomaux" of the ordre " Carna-ssiers." 



1817. Cuvier removes "les Amphibies " from the vicinity of the Cetacea, 



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