506 



THE CAT. 



In Miacis* on the other hand, the astragalus is flat, but in the 

 lower jaw " we have a near approach to the dentition of the dogs/' 



Didymictisy I from the American lower eocene, is closely allied to 

 MiaciSy differing only in having one less inferior tubercular molar. 



Palceonictis t is a genus which is thought to resemble the Viverrine 

 Carnivora in its teeth, save that the second lower true molar is 

 rather sectorial unlike that of existing carnivorous mammals. 



Amblyctonus seems only to differ from the last in that its fourth 

 inferior premolar supports tubercles instead of a cutting edge. 



Patriofelis || is a genus founded on some fragments of a jaw ob- 

 tained by Professor Hayden from near Fire Bridge, Wyoming. It 

 was larger than the panther, the lower jaw being six inches long. 

 It has similar characters to those of Mesonyx, save that there are 

 only five lower molars instead of seven. 



Hycenodon*k is a well-known European form, but is found in 

 America also. It has also sectorial molars in large number, but its 

 brain ** was formed on the same type as that of the existing carni- 

 Hycenodon has a scapho-lunar bone. * 



vora. 



Arctocyon, the oldest mammal yet discovered posterior to the 

 mesozoic epoch, is another long and well-known European fossil \ \ 

 animal of the lower eocene. It is almost as large as a wolf, with a 

 long tail and a much curved humerus with a strong deltoid ridge. 

 The skull is very narrow between the middle of the zygomatic 

 arches, and has large palatine foramina. The brain had large 

 olfactory lobes and a small cerebrum which left the cerebellum and 

 probably the corpora quadrigemina uncovered and was almost un- 

 convoluted. There were seven upper molars. The first of these 

 had one root, the second and third two roots, then came a triangular 

 tooth (slightly sectorial in character), followed by three tubercular 

 molars, the last but one being the largest. The teeth were gene- 

 rally tubercular. The ankle joint is unknown. 



Cynodon J J is an upper eocene form, considered by M. Gaudry as 

 intermediate between the dogs and civets, some species being more 

 like one and others more like the other of these two types. Like 



* Cope's paper on Creodonta, pp. 3 

 and 58. 



t Cope, 1. c., p. 3. 



J Cope, I. c., pp. 3 and 6. See also 

 Gaudry, /. c., p. 19, fig. 11 ; and 

 Gervais, Pale'ontol. Fran?aise, p. 225, 

 plate 25, figs. 11, 12. 



Cope, 1. c., p. 3. 



|| See United States Geological Survey 

 of Territories, vol. i, p. 114, plate 7, 

 fig. 20 ; and Pro. Acad. Nat. Sc. 

 Philadel., March, 1870, p. 11, plate 2, 

 fig. 10. 



IT See Gaudry, I. c., p. 14, figs. 3 and 

 4 ; also Gervais, PaL Franp., p. 232, 

 plate 24; Filhol, Ann. des Sc. Geol., 

 vol. 7, p. 162 ; and Leidy's Mammals of 

 Dakota and Nebraska, Journal Acad. 



Philadel. vii., p. 39, plate 2 ; and 

 De Blainville's Osteog. (Canis), p. 17 ; 

 and De Laizer and De Parien, Ann. 

 des Sc. Nat., 2nd series, vol. xi., 1832. 



** Nouvelles Ann. du Musdum, 

 1870, plate 6, fig. 7. 



ft De Blainville (Subursus), p. 73, 

 plate 13 ; Gervais, Pale'ontol. Fran9. p. 

 220 ; and Nouvelles Ann. du Mus., 

 vol. vi., p. 147, plate 6, fig. 4 (brain) ; 

 Gaudry, I. c., pp. 22-24, fig. 14. 



JJ See Gervais, Pale'ontol. Fran., p. 

 218, plate 15 ; and Aymard, Ann. de 

 la Soc. Acad. du Puy, vol. xv., p. 92, 

 1851 ; also Gaudry, 1. c., p. 215, figs. 

 282 and 283. M. Filhol has shown the 

 great variability of Cynodon. 



