1857.J OWEN DICHOBUNE OVINA. 255 



chioness of Hastings, and now forms part of the Palseontological 

 collection in the British Museum. The dental formula, as shown 

 by the mandibular teeth, and by the evidence on their crowns of the 

 presence of the teeth of the upper jaw, is the typical one in diphyo- 



dont* Mammalia ; viz., i ^;:3^, c ^zii' P jz:^, m ^3^=44. The canine, c, 

 with a crown like that of the first premolar,^ 1, and not longer, is 

 separated from it by an interval of half the breadth of the crown and 

 by a narrower interval from the outer incisor, i 3. The first pre- 

 molar, p \, is divided by an interval of scarce a line's breadth from 

 the second, p 2. The rest of the molar series are in contact. 



The total length of the lower jaw is 5 inches 11 lines (0"*148) ; 

 that of the molar series is 2 inches 1 1 lines (0™*075) ; that of the 

 three true molars is 1 inch 4^ lines (0™'035). 



The near equality in height of the crowns of all the teeth, and 

 their general character, show that the animal belonged to that group 

 of the Anoplotherioid family which includes the genera Dichobune 

 and Xiphodon of Cuvier. The dentition of the present species dif- 

 fers from that of Bichodon in the absence of the accessory cusps on 

 the inner side of the base of the true molars, fig. 3, ml, 2, 3, and 

 both from Dichodon cuspidatus f and Xiphodon gracilis X in the 

 minor antero-posterior extent of the premolars : it corresponds with 

 Dichobune (as represented by the Dick, leporina, Cuv.§) in the 

 proportions of the premolars and in the separation of the canine from 

 the adjoining teeth : to this genus, therefore, the fossil is referable, 

 provisionally, in the absence of knowledge of the molars of the upper 

 jaw, which are the most characteristic ; and I propose to call the 

 species, from the size of the animal represented by the fossil, Dicho- 

 bune ovina. The lower jaw differs in the broader or deeper hori- 

 zontal ramus, and in the less oblique ascending ramus, from that 

 of the Dichobune leporina figured by Cuvier ||. 



The outer incisor, i 3, has a short and broad crown reduced by the 

 attrition of the summit to a semioval shape, with the external con- 

 vexity interrupted by a feeble conca\dty near the hind border, the 

 inner side having the middle convexity passing into a slight concavity 

 on each side ; but it has no basal ridge and fossa, as in Dichodon. 

 The crown is covered by a moderately thick enamel, well-defined 

 from the fang. 



The canine, c, has a similar, but larger and more pointed crown, 

 with a very feeble indication of a hinder lobe, and deeper concavities 

 before and behind the median convexity of the inner surface. The 

 crown is worn at the summit and along the anterior slope, exposing 

 a linear tract of dentine ; it expands abruptly, before and behind, 

 above the fang. 



The first premolar, ^^ 1, is smaller than the canine, but resembles 

 it in shape, save m a less feeble indication of the hind basal lobe, the 



* Philosophical Transactions, 1850, p. 493. 



t Quarterly Journal of the Geological Society, vol. iv. June 1847, p. 36, pi. 4. 



+ Osseniens Fossiles, ed. 1836, torn. v. p. 105, pi. 133. 



§ lb. torn. V. p. 110, pi. 90. fig. 1. II lb. 



