MR. E. LTDEKKER OlST DACRYTHERIUM 0VINT7M. 3 



side of the ramus and the oral surface of the teeth. The ramus has 

 lost the summit of the coronoid process and part of the " angle," as 

 well as the extremity of the symphysis. The three true molars, 

 the first three premolars, and the canine are perfect, but the crown 

 of the fourth premolar is broken ofi", and the incisors are wanting. 

 The jaw agrees in all its proportions with the cranium, this being 

 especially shown by the small premolariform canine, separated by a 

 short interval from the first premolar ; so that, altogether apart from 

 the alleged association, I feel no hesitation in referring it to the 

 same species as the cranium. The three remaining premolars are 

 trenchant teeth, the second and third being almost in contact, but 

 the small first one being separated from the second by an interval 

 about the same as that which divides it from the equally small and 

 nearly similar canine. 



Compared with the type of Dichohune ovina, PI. I. fig. 3, in which 

 the first and second incisors are wanting on both sides, the present 

 ramus agrees so exactly as not only to confirm my reference of the 

 former to Dacrytherium, but likewise to show that both the Prench 

 and English specimens belong to a single species. 



If, however, we compare the mandible represented here with 

 the one figured by Filhol in the ' Ann. Sci. Geol.' vol. viii. pi. x. 

 figs. 254-256, we shall find such marked differences between them 

 as to show that they cannot belong to the same form. Thus in the 

 latter the second and third premolars are larger than in the present 

 specimen, while the canine, instead of being a small, upright, 

 premolariform tooth, is comparatively large, proclivous, and incisor- 

 like ; while the incisors themselves are also proclivous. If the 

 length of the dental series in the mandible figured by Filhol be 

 compared with that of the upper dental series, it will be seen at 

 once to be too short, while the proclivous incisor-like canine and 

 incisors are not the sort of teeth, either in place or position, which 

 could be opposed to the corresponding teeth of the upper jaw, I 

 have, therefore, no hesitation in concluding that the mandible 

 figured by Eilhol as that of Dacryther'ium belongs to another form ; 

 and consequently that his D. Cayluxi is specifically the same as the 

 so-called Dichohune ovina. The synonymy of that species will 

 accordingly be as follows, viz. : — 



DACRTTHEEItTM OVINFM (Owcn), 



Dichohune ovina, Owen, 1857. 



? Hyopotarmis Gresslyi, Pictet, 1869 (non Tapinodon Gresslyi, Meyer). 



Dacrytkerium Cayluxi, Filhol, 1876. 



? Hyopotamus Picteti, Lydekker, 1885. 



Dacrytheriiim cayluxense, Lydekker, 1885. 



Dacrytkerium ovinum, Lydekker, 1885. 



This identification of the French with the English species of 

 Dacrytherium adds one more to the list of mammals common to the 

 Phosphorites and the Headon beds, and thus tends to confirm the 

 accumulating evidence that the former should be regarded as of 

 Lower Oligocene (Upper Eocene) rather than Middle Oligocene 

 (Lower Miocene) age. It may be added that my suggested iden- 



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