NO. 2 A STUDY OF MENISCOTHERIUM — GAZIN Q 



but in the second edition of his textbook (1937) this latter opinion 

 was modified by the statement that the hyracoids were probably 

 derived from Old World condylarths. Schlosser in his study of the 

 Fayum hyracoids (1911) pointed out that although there was a 

 resemblance in foot structure between M eniscotherium and the hyra- 

 coids, the tooth structure resemblance is with the recent hyracoids 

 and only one Fayum form (Saghatherium) . Greater divergence was 

 noted with respect to the bunodont hyracoids of the Fayum. Much 

 more recently Simpson (1937) has referred to meniscotheres as 

 "hyracoidlike" and (1945) in commenting on the hyracoids has 

 observed that ". . . no one has ever fully examined and logically 

 interpreted numerous resemblances, probably but not surely super- 

 ficial, to various other groups, notably to the meniscotheres and 

 notoungulates." 



The European Paleocene genera Pleuraspidotherium and Ortha- 

 spidotherium had a varied history of interpreted relationship, as out- 

 lined by Teilhard de Chardin (1922), but in their later treatment, 

 following Zittel (1893), came to be regarded by Weber (1904) and 

 Schlosser (in Zittel and Schlosser, 1923), for example, as having 

 condylarth affinities. It may be noted, however, that following his 

 description of these genera in 1878, Lemoine, in 1892 (see Teilhard 

 de Chardin, 1921-1922, p. 37), thought that Orthaspidotherium 

 belonged in a position ancestral to the artiodactyls, an idea that was 

 adopted by Schlosser in 1911 (in Zittel and Schlosser). Teilhard 

 de Chardin in 1920 (and 1922) convinced of a closer relationship 

 to the meniscotheres, included both Pleuraspidotherium and Ortha- 

 spidotherium in the Meniscotheriidae. This assignment was adopted 

 by Simpson (1937) but with subfamily separation of Pleuraspido- 

 theriinae and Meniscotheriinae. In 1929, however, Simpson noted 

 the distinctive features of Orthaspidotherium but regarded Schlosser's 

 (Lemoine's 1892) suggestion of an artiodactyl relationship as highly 

 improbable. Most recently D. E. Russell (1964) has described more 

 fully the Pleuraspidotherium materials from Cernay and, with 

 detailed consideration of relationships, has followed Teilhard de 

 Chardin and Simpson in including Orthaspidotherium as well as 

 Pleuraspidotherium in the Meniscotheriidae. 



GEOGRAPHIC AND GEOLOGIC OCCURRENCE 



The known distribution of M eniscotherium is included geographi- 

 cally within the states of Wyoming, Colorado, and New Mexico in 

 this country and in Alberta, Canada. Geologically it ranges from 



