318 Royal Society. 



ject which approaches the present state of the science ; and from the 

 same arrangement hemg used as that adopted in the British jMuseum, 

 it forms an excellent manual for that collection. 



In the Press. 



A Naturalist' s Rambles on the Devonshire Coast. 

 By P. H. GossE, A.L.S. 

 This work will embody the result of researches and observations 

 made by the author among the rocks, caves and tide-pools of the 

 interesting shores of North and South Devon ; and will comprise the 

 most beautiful and interesting forms of sea-side Natural History, 

 many of which are as yet undescribed. 



PROCEEDINGS OF LEARNED SOCIETIES. 



ROYAL SOCIETY. 



Jan. 1.3, 1853. — A paper was read, entitled " Description of some 

 species of the extinct genus Nesodon." By Prof. Owen, F.R.S. 



The author commences by referring to a genus of extinct herbi- 

 vorous mammals which he had founded in 1836, on certain fossil 

 remains discovered in Patagonia, and which, from the insular dispo- 

 sition of the enamel folds characteristic of the molar teeth, he had 

 called Nesodon. Subsequent transmissions of fossils from the same 

 part of South America, by their discoverer, Capt. Sulivan, R.N., now 

 enabled the author to define four species of the genus. The first 

 which he describes is founded on a considerable portion of the cra- 

 nium and the lower jaw, with the teeth, and is called Nesodon 

 ovinus. After the requisite osteological details and comparisons the 

 author proceeds to describe the three incisors, the canine, and five 

 molar teeth, which are present on each side of both upper and lower 

 jaws, and then enters upon an inquiry as to the nature and homo- 

 logies of the grinding teeth. The result is to show that the first 

 four molars belong, with the incisors and canines, to the deciduous 

 series, and that the fifth molar is the first true molar of the perma- 

 nent series ; the germ of a second true molar was discovered behind 

 this, in both the upper and the lower jaws, whence the author con- 

 cludes that the Nesodon ovinus had the typical number of teeth when 

 the permanent series was fully developed, viz. i ^^, c —^y P 



4—4 



The structure of the grinding teeth proving the extinct animal to 

 have been herbivorous, the number and kinds of teeth in the entire 

 series show that it was ungulate. In this great natural series of mam- 

 malia the author next shows that the Nesodon had the nearest afli- 

 nities to the odd-toed or Perissodactyle order amongst the existing 

 species ; but certain modifications of structure, hitherto peculiar to 

 the even-toed or Artiodactyle Ungulates, are repeated in the cranium 

 of the Nesodon : more imjiortant marks of affinity are pointed out in 

 the Nesodon to the Toxodon; and both these extinct forms of South 



