ANNIVERSARY ADDRESS OF THE PRESIDENT. lxxxi 



palceotherium (Gervais), Macacus or Eopithecus, and Hyracotherium 

 have been established. This last-named fossil genus was founded upon 

 " the portion of a cranium with the molar series of teeth ;" and as he 

 was enabled to determine a new genus, named by him Pliolophus vul- 

 piceps, on " an entire skull with the complete dentition of both upper 

 and lower jaws, and a portion of the skeleton of the same individual, 

 including the right humerus, the right femur, a great part of the 

 left femur, the left tibia, and three metatarsal bones, apparently 

 of the same hind foot," and many other recognizable and import- 

 ant portions of the skeleton, he justly states that " it is the most 

 complete and instructive mammalian fossil of the age of the Lon- 

 don Clay which has hitherto been discovered, and its study is 

 replete with interest. It was brought to the British Museum by 

 Mr. Colchester, being imbedded in one of the Eoman- cement nodules 

 of the London Clay, near Harwich. The osseous tissue is fossilized, 

 and partly impregnated with pyritic matter. It is well known how 

 rich the cement-nodules are in fossils ; and, a fragment having been 

 chipped off the present one, the attention of the workmen was 

 arrested by the appearance of what appeared to them the head of a 

 fox. The specimen then came into the possession of the Eev. 

 Richard Bull, M.A., vicar of Harwich, who placed it in the hands 

 of Mr. Colchester to obtain the opinion of Professor Owen on its 

 true character and relations. By him it was recognized as a new 

 species, forming the type of a new genus, which he has named 

 Pliolophus, meaning to imply that it was nearer to the Lophiodont- 

 type than its close ally the Hyracotherium : the whole name Plio- 

 lophus vulpiceps, or Pox-headed Plioloph, expresses the peculiar 

 form already alluded to. 



It is unnecessary that I should enter into the anatomical details, 

 worked out, as they have been, with the usual skill of Professor 

 Owen ; but I may mention some of the results. One portion of 

 the cranium approximates the specimen to the carnivorous type, 

 whilst in other respects it follows the rule of the Hog, Hyrax, and 

 Palseothere — resembling, in the proportions of the zygomatic arches, 

 the Palceotherium more than any existing mammal. In a similar 

 manner its approximation on the one hand to, and its divergence, on 

 the other, from several other genera, such as the Rhinoceros, Tapir, 

 Horse, and Hyrax, Anoplotherium and Hyracotherium, are minutely 

 investigated, as are also the similarly partial approximation and par- 

 tial divergence in affinities as exhibited by a conjoint comparison of 

 the skull and teeth of Pliolophus and various other genera. Professor 

 Owen then states that Lophiodon, Pachynolophus, Pliolophus, and 

 Hyracotherium form so many sub-generic modifications of the same 

 natural family of Perissodactyle Ungulates, and that in the compara- 

 tive simplicity of their premolars, and the progressive approach to 

 the molar type of the Chaeropotamoids, the Pliolophus and Hyraco- 

 therium both exhibit a tendency to a closer adherence to the general 

 Ungulate type. 



Professor Owen then observes that, " in stating that these modified 



