ANCYLOPODA. COXDYLARTHRA. 609 



is a large step from the admission of that possibility to the definite asser- 

 tion that they are the ancestors of that order. 



The Conoryctidae with Conoryctes and Onychodectes Cope, from the 

 Puerco Eocene, are possibly allied here. 



Order 13. ANCYLOPODA.* 



Plantigrade forms with 3 or 5 digits apparently ending in claws. They 

 appear to have possessed characters common to a number of groups. 

 When first discovered they were placed with the Edentata, but their 

 grinders are perissodactyl-like, On the other hand they may be without 

 a third trochanter on the femur and the axis of the limb does not pass 

 through the third digit. The bones of the two carpal rows alternate, but 

 the tarsals are serial. They are found in the Cretaceous and Eocene of 

 Patagonia, in the Eocene of Europe, the Miocene of Europe, America and 

 Asia and a few in the Pliocene. Homalodontotherium Huxley, penta- 

 dactyle (Fig. 320), complete dentition, Eocene, Patagonia ; Chalicotherium 

 Kaup., tridactyle, without incisors, Miocene, Europe ; Macrotherium 

 Lartet, Miocene, Europe. 



Order 14. CONDYLARTHRA.f 



Extinct, plantigrade or digitigrade animals with pentadactyle 

 limbs, without hoofs ; without a clavicle. Carpalia and tarsalia 

 sometimes serial, sometimes interlocking. The carpus 

 usually with a centrale. Dentition complete ; grinding teeth 

 brachyodont and bunodont. The humerus has an entepicondylar 

 foramen and the femur a third trochanter. From the Eocene 

 of America, and a few remains in the Eocene of Europe. 



They had a very small brain with an uncovered cerebellum 

 and a smooth cerebrum. The skull is elongated with orbits 

 widely open behind, the frontals and jugals being devoid of 

 postorbital processes. The canine teeth are not much 

 enlarged and the premolars are simpler than the trituber- 

 cular or quadritubercular molars. There is no clavicle. The 

 humerus has an entepicondylar foramen, therein differing 

 from that of Ungulata. They are commonly described as 



* Ameghino, Enum. Synopt. des Mammif. tert. de Patagonie, 1894. 

 Flower, Homalodontotheriu^i, Phil. Trans., 1874. Huxley, Quart. J. 

 Geol. Soc., 1870. Filhol, Etudes sur les Mammif. de Sansan, Ann. Sci. 

 geol., 1891, 21. Osborn, Amer. Nat. 22, 25, 26, 27, 1889-93. Cope, 

 Amer. Nat., 1889, p. 658. 



f Cope, Synopsis of the Vert. Fauna of the Puerco Series, Amer. Phil. 

 Soc., 16, 1888. Osborn and Earle, Fossil Mam. of the Puerco Beds., Bull. 

 Amer. Mus. N. Hist., 7, 1895. Matthew, A Revision of the Puerco Fauna, 

 ibid,, 9, 1897, p. 259. Osborn, Phenacodus, ibid., 10, 1898. Marsh, 

 Hyracops, Amer. Journ. Sci. (3), 43 1892. 



Z ir. E 1. 



