Prof. Owen 07i PHolophus vulpiceps. 531 



hind foot. Many portions of ribs and vertebrae remained imbedded 

 in the hard matrix. 



The septarian nodule containing the aljove parts was transmitted 

 to the author by the Rev. Richard Bull, M.A., Vicar of Harwich, 

 by whose permission the bones were extricated, described, andtigured 

 for the present communication. 



The length of the skull is 4 inches, its extreme breadth 2 

 inches 2 lines, the height of the cranium opposite the first pre- 

 molar tooth 9 lines. Its shape and characteristics determine the 

 hoofed nature of this species and its affinities to the Perissodactyla, 

 or the order of Ungulata with toes in odd number. 



The orbit, 9 lines in vertical diameter, is smaller than in the 

 Hyracotherium, and is not situated so low down as in that animal, 

 the Palffiotherium, and the Tapir. The dentition accords with the 

 type of the diphyodont Mammalia, viz. i '^' c ^^, ^ ji^j' m ^^^^AA. 

 The characters of these teeth were described. The canines are 

 small in both jaws : they are separated by a vacant space from the 

 outer incisors, and by a longer interval from the first premolars. 

 These form a continuous series with the remaining teeth in the 

 upper jaw, but are separated by a space of about half their breadth 

 from the second premolar in the lower jaw. The succeeding teeth 

 increase in size to the penultimate molar in the upper, and to the 

 last molar in the lower jaw, which tooth has a third lobe. 



In his comparisons of the modifications of the grinding surface of 

 the teeth, the author remarked that the generic or family type of the 

 Lophiodont upper molars is, to have the outer wall developed into 

 two cones, from each of which is continued an oblique ridge ^yhich 

 expands into, or joins, a smaller and lower cone on the inner side of 

 the crown. 



In Pachynolophns, a subgenus of Lophiodonts foundedby M. Pomel, 

 on a species of the size of the PHolophus from the calcaire grossier of 

 Passy near Paris, the oblique ridges are lower at their commencement 

 and more partially expanded in their course inward than in Lophiodon 

 proper. In PHolophus the partial expansion is more circumscribed, and 

 forms a small intermediate tubercle, except on the ridge at the hinder 

 half of the last upper molar. In the lower ]a\voiPachj/nolophus the first 

 premolar, according to the description and figure given by M. Ger- 

 vais (Paleontologie Fran9aise, 4to, pi. 17, figs. 1 & 2), is not 

 developed, and the canine is separated from the molar series by a 

 diastema of twice the length of that in PHolophus. This latter genus, 

 therefore, is more nearly allied, in respect of the number and position 

 of its teeth, to Lophiodon proper ; but it differs from all previously 

 known Lophiodonts in the modification of the grinding surface ot 

 the molars of the lower jaw. This surface in Lophiodon, Pachyno- 

 lophus, Lophiotherium, Tapirulus, and Coryphodon presents two trans- 

 verse ridges connected by a diagonal ridge : whereas each transverse 

 ridge in PHolophus is divided into a distinct cone, the anteri(jr pair 

 on the second true molar being separated by an intermediate small 

 cone, thus affording, as in the Htercoynathus, an instance of three 

 cones on the same transverse line in a lower molar tooth. In the 

 last true molar the anterior pair of cones are united by a low and 



