1XXX PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



from a specimen obtained from the lignites of Debruge, near Apt. 

 M. Gervais had given his reasons for considering the genus Xiphodon 

 very approximate to Hyojpotamus ; but Professor Owen points out 

 that both, Anthracotherium and Hyopotamus differ from Anoplothe- 

 rium, Xiphodon, and Dichodon, by the interrupted character of the 

 dentition, which in the latter genera is continuous. The genus Di- 

 chobune had been also separated by Cuvier from the genus Anojolo- 

 therium, the species A. minus and A. leporinum having been 

 transferred to this new genus, which is closely connected with the 

 genus Xiphodon ; it is, indeed, manifest that most able palaeontolo- 

 gists have found it sometimes difficult to determine between such 

 closely- allied genera, M. Gervais having in like manner transferred 

 the species Hyracotherium Robertianum to the genus Dichobune. 

 Professor Owen also made some interesting observations on the 

 consequences of adopting the analogy of Microtherium or of Anoplo- 

 therium in determining the fore or back parts of the crown of the 

 upper molar — an important point in settling the relations of a new 

 genus, — he himself adhering to the Anoplotherium. 



In respect to the first appearance of true Euminants, Professor 

 Owen remarked that the dentition of the upper jaw of the species 

 Anoplotherium murinum and A. obliquum, referred by Cuvier to his 

 genus Dichobune, must be known before the existence of true Eumi- 

 nants in the Upper Eocene gypsum of Paris can be inferred. The 

 following interesting remark closed his statement, and is worthy of 

 careful attention ; for, whilst it speaks of a formative force being 

 transferred from one set of teeth to another, as an easy mode of effect- 

 ing a transition, and shows how easily the Euminant stomach might 

 have been modified, it is impossible not to imagine how readily many 

 transmutations might have been effected in the progress of time, 

 without the aid of renewed creation. " No doubt the affinity of these 

 small Anoplotherioids to the Chevrotains was very close ; let the for- 

 mative force be transferred from the small upper incisors to the con- 

 tiguous canines, and the transition would be effected. We know 

 that the Euminant stomach of the species of Tragulus is simplified 

 by the suppression of the psalterium, or third bag ; the stomach of 

 the small Anoplotherioids, whilst preserving a certain degree of 

 complexity, might have been somewhat more simplified. The certain 

 information which the gradations of dentition displayed by the above- 

 cited extinct species impart, testifies to the artificial character of 

 the order Euminantia of the modern systems, and to the natural cha- 

 racter of that wider group of even-toed hoofed animals, for which 

 I have proposed the term Artiodactyla." 



The next paper by Professor Owen was one on a small Lophiodont 

 Mammal from the London Clay, near Harwich. Professor Owen 

 first points out the rarity, and usually fragmentary condition, of the 

 remains of mammals found in Eocene beds below the Binstead, Gyp- 

 seous, and Headon or Hordwell series, either in our own country or 

 on the Continent, and illustrates this position by referring to the 

 fossil evidence upon which the genera Pachynolojohus, Dichobune, Pro- 



