. Central Asiatic Expeditions of the American Museum of Natural History, under the leadership of Roy Chapman Andrews : preliminary contributions in geology, palaeontology, and zoology. Central Asiatic Expeditions (1921-1930); Scientific expeditions; Natural history; Scientific expeditions; Natural history. Fig. 6. Eudinoceras. Upper premolar, No. 20134, natural size, external and crown Fig. 7. Acha>nodont. Supposed upper milk molar, No. 20136, nat- ural size, crown view. Artiodactyla Achaenodontidae No. 20136, an incomplete upper tooth, is doubtfully identified as dp^ of an achsenod
. Central Asiatic Expeditions of the American Museum of Natural History, under the leadership of Roy Chapman Andrews : preliminary contributions in geology, palaeontology, and zoology. Central Asiatic Expeditions (1921-1930); Scientific expeditions; Natural history; Scientific expeditions; Natural history. Fig. 6. Eudinoceras. Upper premolar, No. 20134, natural size, external and crown Fig. 7. Acha>nodont. Supposed upper milk molar, No. 20136, nat- ural size, crown view. Artiodactyla Achaenodontidae No. 20136, an incomplete upper tooth, is doubtfully identified as dp^ of an achsenodont. It is too incomplete for positive reference. The outer border of the tooth is missing, but it appears to have been of rounded subtrigonal outline with two major outer cusps (paracone, metacone) rounded and well separated, a smaller internal cusp (proto- cone) and a much smaller postero-internal cusp (hypocone) which stands a little apart but not far from intermediate between protocone and metacone. The tooth has some resemblance to dp^ of the entelodonts, differing in absence of the conules, which are well developed in the deciduous as also in the permanent molars of entelodonls. In the achaenodonts thej^ are absent in the permanent molars; dp^ is not known, but presumably would conform to the permanent molar construction. The Mesonychidse have a similarly simple construction of the molars, but lack the hypo- cone ; dp^ appears to be unknown in Mesonychidae but presumably would also conform to the permanent molar pattern and lack a hj^pocone. The above reasons warrant a provisional reference of No. 20136 to the Achsenodontidae. We agree with Peterson that this group is not ancestral to the entelodonts, and probably onlj^ distantly related.^ 'This view was indicated by Matthew in 1899, Achxnodon and Protelotherium being referred to a separate family from Please note that these images are extracted from scanned page images that may have been digitally enhanced fo
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