232 Geological Society : — Anniversary of 1839. 



most nearly allied to the Peccari. A fragment of a lower jaw of 

 the same genus, fomid by Mr. Darwin Fox in the Isle of Wight, 

 confirms this view, but indicates in some points an approach to 

 the carnivorous type. And it was remarked as interesting, that 

 the living genus of the hog tribe which most resembles the Chse- 

 ropotamus, the Peccari, exists in South America, where the Ta- 

 pir, the nearest living analogue of the Anoplothere and Palaeo- 

 there, the associates of the Chaeropotamus, also occur. Another 

 jaw, found by Mr. Pratt in the Binstead quarries in 1830, and re- 

 sembling that of the Musk Deer, Mr. Owen refers to a new species 

 of Cuvier's genus Dicobune, under the name Dichobune cervi- 

 num. Mr. Owen has also given us a description of Lord Cole's 

 specimen of Plesiosaurns macrocepJtalus, which he compares 

 with Mr. Conybeare's Plesiosaurns JDolicIwdeirus, by establish- 

 ing an intermediate species, founded upon a specimen existing in 

 the British Museum, and termed by him Plesiosaurns Haickinsii. 

 Besides tracing the analogies which connect these with each 

 other, and comparing them with the two great modifications of 

 the saurian tribe, the crocodiles and the lizards, Mr. Owen pre- 

 sented his remarks on the form of the Plesiosaurian vertebrae, 

 founding them upon a general view of the elements of which all 

 vertebrae are constituted. 



To the communications thus made to us, we may add Mr. 

 Owen's determination of another animal, of which the remains 

 brought from the neighborhood of Buenos Ayres, are among the 

 many treasures of this kind which we owe to Sir Woodbine Pa- 

 rish. This animal, of gigantic dimensions, appears to have been 

 alUed to the Megatherium, but with closer affinities to the Arma- 

 dillos ; and it probably possessed the characteristic armor, of 

 which, in the Megatherium, the existence is perhaps problemati- 

 cal. Mr. Owen has termed it Glyptodon, from the furrowed 

 shape of its teeth. 



In another communication, Mr. Owen endeavored to account 

 for the dislocation of the tail of the Ichthyosaurus at a certain 

 point, which is observable in many of the fossil skeletons of that 

 animal. This circumstance, so remarkable from its general oc- 

 currence, and which Mr. Owen was the first to observe, he is dis- 

 posed to account .for, by supposing a broad tegumentary fin to 

 have been attached to the tail for a portion of its length, the posi- 

 tion of which fin must, he conceives, have been vertical. 



