1857.] OWEN DICHOBUNE OVINA. 259 



4to, torn. iii. 1822, p. 64, for the Anoplotherium minus of the original 

 Memoir, in the *Annales du Museum,' tom. iii. (1803), and for the 

 Anopl. leporinum of the 4to edition, 1822, tom. i. pi. 2. fig. 3, and 

 tom. iii. pp. 70 and 251 *. It is closely alhed to the Anoplotherioid 

 genus Xiphodon ; the dental formula is the same, only there is a 

 slight interval between the canine and the first premolar in both 

 jaws : the first three premolars are subcompressed, subtrenchant, 

 but less elongated from behind forwards than in Xiphodon. Besides 

 the two normally developed and functional digits on each foot, there 

 be one, sometimes tw^o, supplemental digits. 



The best illustration of the structure of the upper true molars is, 

 perhaps, afforded by the figure of one of these teeth in the * Proceed- 

 ings of the Geological Society,' May 20th, 1846, published in the 

 * Quarterly Journal,' vol. ii. p. 420. ** The Anoplotherian charac- 

 ter of the tooth is shown by the large size of the lobe, p, cc, fig. 1, 

 and the subgeneric peculiarity by the continuation of its dentinal 

 base with that of the inner and anterior lobe, i d, at the early stage 

 of attrition presented by the crown of the tooth in question. In the 

 large and typical Anoplotheria, the lobe, p, preserves its insular form 

 and uninterrupted contour of enamel until the crown is much more 

 worn down (than in the present tooth, fig. 1). In this respect, as in 

 the modifications of the lower molar teeth, the genus Dicliohune 

 shows its closer affinity to the true Ruminants ; but the little fold of 

 enamel dividing the lobe ^ d from p distinguishes the upper molar 

 tooth in question from that of any Ruminant." (p. 421.) 



Two upper molars, originally referred by M. Gervais to the genus 

 Hyracotherium f, have since been figured by him, and referred, ana- 

 logically, to his Dichobiine Rohertiana X- They unquestionably cor- 

 respond more closely with the upper molar referred by me to the 

 genus Bichobune than to the upper molars of Hyracotherium. They 

 show, as M. Gervais describes, " cinq pointes tuberculeuses placees 

 sur deux rangs, trois au premier rang et deux au second." (p. 6.) 



In the characters of the genus JDichohune given by M. Gervais in 

 the text, he describes the upper true molars as formed " de deux 

 rangs de pyramides obtuses ; deux pyramides en avant ou au premier 

 rang et trois en arriere, c'est-a-dire au second rang." 



Whether this ascription of the three cones or points to the hinder, 

 instead of the fore, division of the molar tooth be based upon an ob- 

 servation of those teeth in situ in the upper jaw, or upon the analogy 

 of the Microtherium {Cainotherium, Lartet) is not stated. The teeth 

 of the Bichobune Robertiana were found detached in the marl of 

 the " calcaire grossier" : the upper molar from the Binstead Eocene, 

 referred by me to the genus Bichobune, was also a detached speci- 

 men. Entire crania of Microtherium^ from the lacustrine calcareous 

 marls of the Puy-de-D6me, are in the British Museum, and these 



* " EUe formera aussi pour raoi le type d'un sous-genre que je noramerai Di- 

 cJiohune, a cause de ces pointes ou collines disposees par paires sur les quatre 

 dernieres molaires." — Ed. cit. p. 64. 



t Compte Rendu dc I'Acaderaie des Sciences, t. xxxi. p. 552. 



X Paleontologie Frangaise, pi. 35. fig. 12. 



