H. LydeliJier — On Fossil Mammalia. 63 



III. — Note on Threr Genera of Fossil Artiodactyla, with 

 Description of a New Species. 

 By R. Lydekkek, B.A., F.G.S., F.Z.S. 



CiENOTHERIUM FiLHOLI, Sf. nOV. noblS. 

 From the Querci/ Fhosphorites. 



IN his memoir on the Vertebrates of the Quercy Phosphorites, 

 Dr. Filhol has described two species which he refers to the 

 genus Ccsnotherium, viz. C. commune ^ and C. eJongatum.~ Of the 

 former only one ramus of the mandible is figured, and it is referred 

 to a varietal form under the name oi pro commune : the latter, which 

 is a small form, is known by the cranium and mandible. Both 

 species have no diastema in the dental series. In addition to these, 

 two small species are referred to the genus Plesiomeryx, under the 

 names of P. cadurceyisis ^ and P. qiiinquedentatus,^ the latter being 

 known only by the mandible ; these forms are distinguished from 

 the true Ccenotherium by the presence of a diastema between the 

 earlier premolars. 



From the Lower Miocene of Cournon (Puy-de-D6tne) and St. 

 Gerand-le-Puy (Allier) Dr. Filhol recognizes three species of 

 Ccenotlierium proper, viz. C. commune,'' C. laticurvatum,^ and C. 

 Geoffroyi ; ' and one species of Plesiomeryx, viz. P. gracilis.^ The two 

 latter are of very small size ; and G. laticiirvatum is the largest of all. 

 In a later memoir ^ the same writer describes a lower jaw from the 

 Lower Miocene of Eonzon, near Puy-en-Yelay, which is also referred 

 to P. gracilis, although it presents no diastema. This specimen 

 is the type of Aymard's ill-defined Zooligus Picteti (= C. Picteti, 

 Gervais) ; and on its evidence Dr. Filhol says that no distinction 

 derived from dental characters can be drawn between Gcenotheriiim 

 and Plesiomeryx ; although the latter is retained as a sub-genus 

 marked by certain cranial characters. The present writer prefers 

 to altogether abolish the latter term. From the Upper Eocene of 

 Mouillac, France, Dr. Filhol ^" has more recently described a frag- 

 ment of the maxilla of an allied form containing the last five teeth 

 under the name of Mouillactherium elegans. The specimen has not 

 been figured ; but it is described as differing from typical species of 

 Ccenotherium by having a larger and more forwardly placed inner 

 cusp to P^^, by the absence of the third cusp on the hinder lobe 

 of m. 3, and by the presence of a diastema between pm. 2 and pm. 3. 

 The sj)ecies is of small size, the length of the space occupied by the 

 three true molars being 0011. Tlie generic distinctness of this 

 form may perhaps be doubted. The following table indicates the 

 chief characters of the eight species mentioned above. 



1 Ann. Sci. Geol. vol. viii. art. 1, p. 212, pi. xii. pi. xii. figs. 269-70 (1877). 



2 Ibid. p. 212, pi. xii. figs. 27o-8. » Ibid. p. 205, pi. xii. figs. 271-4. 



* Ibid. p. 430, pi. xix. tigs. 314-16. ^ j/^id^ vol. x. art. 3, p. 213, pi. xxviii, 



« Ibid. p. 226. pi. xxix. ■? Ibid. p. 240. 



8 Ibid. vol. xi. pi. 1, fig. 13 (1881). 



' Ifw/. vol. xii. art 3, pp. 77-84, pi. xi. pp. 53-9 (1882). From specimens in 

 the British Museum the writer is inclined to think that U. cadurcciise and 6'. gracile 

 may he identical. Filhol regards them as very closely related. 



i» Ann. Soc. Sci. Phys. Nat. Toulouse, 1882, pp. 128-30. 



