560 THE AGE OF MAMMALS 



SUPERORDER N TO U N G UL A T A. Extinct South American 

 Hool't'(l MiininKils.i 



XXIII. Okuek TOXODONTIA. Toxodonts, with rhinoceros-like grinding 

 teeth. 



1. Sup.OHDKii HoMALODOTHERlA. IIoMialodotheres. 



Fam. Notostylopidae. Notostylopids. 



f Notostylojjs. Notostylops Beds (? Bas. Eoc), S. Amer. 



I Trigonosti/lops. Notostylops Beds (? Bas. Eoc), S. Auier. 

 Fam. Homalodotheriidae. Homalodotheriids. 



f Homalodotherium. Santa Cruz Beds (? U. Mioc), S. Amer. 



Inc. Sed. 



f As)no(leus. Pyrotherium Beds (? Eoc), S. Amer. 



2. Suborder Astrapotheria. Astrapotheres. 



Itic. Sed. Fam. Albertogaudryidae. Albertogaudryids. 



f Alhertogawlr^a. Notostylops Beds (? Bas. Eoc), S. Amer. 



f (?) Astraponntus. Astraponotus Beds (? Bas. Eoc), S. Amer. 

 Inc. Sed. Fam. Isotemnidae. Isotemnids. 



f Isotemnus. Notostylops Beds (? Bas. Eoc), S. Amer. 



Fam. Astrapotheriidae. Astrapotheres. 



■f- Astrapfltherium. Colpodon Beds (? Mioc), and a type species in 

 Santa Cruz Beds (? U.-Mioc), S. Amer. 



3. Suborder TOXODONTIA. True Toxodonts. 



Inc. Sed. Fam. Archaeohyracidae. Archfeohyracids. 



f ArchcBohijrax. Pyrotherium Beds (? U. Eoc), S. Amer. 



f Rhi/nchippus. Pyrotherium Beds (V U. Eoc), S. Amer. 

 Fam. Toxodontidae. Toxodontids. 



■(■ Nesodon. Santa Cruz Formation (? U. Mioc), S. Amer. 



f Toxodon. Pampean (? Plioc & Pleist.), S. Amer. 



f Colpodon. Colpodon Beds (? Mioc), S. Amer. 



4. Suborder Typotheria. Typotheres. 



Fam. Inter atheriidae. Interatheres. 



f Prolijpotherium. Santa Cruz (? U. Mioc), S. Amer. 



1 Vide Weber, Die Siiugetiere, 1904 (under 'Litopterna, Toxodontia,' etc.) : A. Smith Wood- 

 ward, Outlines of Vertebrate Palaeontology, Cambridge, 1898; Voii Zittel, Paliiontologie, IV 

 Bd., Mammalia. Among the numerous monographic researches by Ameghino, Lydekker, Roth, 

 Gaudry, Scott, Sinclair, may be mentioned especially : Lydekker's A Study of the Extinct 

 Ungulates of Argentina, Paleontologia Argentina, II, An. del Museo de la Plata, 1893; the 

 monographs (now in press) by Professor Scott and Dr. Sinclair in the Princeton Univ. Exped.to 

 Patagonia; Sinclair's article, The Santa Cruz Typotheria, Proc. Amer. Philos.Soc, Vol. XLVII, 



1908, pp. ()4-78 ; and Gaudry 's memoirs in the Annales dp PaMontologie (Marcelliu Boule), 190t)- 



1909. The present provisional arrangement is by Gregory. 



