492 Prof. W. B. Scott — Osteology of Ancodus [Hyopotamus). 



I should not have noticed this case were it not for the tendency of 

 some writers to assign all stratified deposits connected with Glacial 

 beds to a mid-Glacial period. The stratified deposits of Lakeland 

 and its neighbourhood are very numerous, but their modes of pro- 

 duction are very diverse, and after many years of work in the 

 district I have seen no proofs of an extensive mid-Glacial sub- 

 mergence there ; everything points to the contrary. 



III. — Notes on the Osteology of Ancodus [S'vopotamus). 



By Prof. W. B. Scott, F.G.S. 

 Professor of Geology in the E. M. Museum of Geology, Princeton, New Jersey, U.S.A. 



IT might well appear that the labours of Kowalevsky and Filhol 

 had so completely determined the structure of this genus, that 

 nothing of importance remained to add to their results ; but this 

 is very far from being the case. The European material, found 

 principally at Hempstead and at Ronzon, near Puy in France, is 

 so scattered that its proper association is a matter of great difficulty, 

 and errors are unavoidable. 



Mr. J. B. Hatcher, Assistant in Geology, and one of the Curators 

 of this Museum, has during the past two summers been engaged in 

 collecting from the Oligocene beds of South Dakota, and among 

 many other treasures has obtained several all but complete skeletons 

 of Ancodus, belonging to the species which Osborn and Wortman 

 have lately named A. (Hyopotamns) hrachyrTiynchus. This material 

 proves to be of great interest and importance, and will be fully 

 described in an illustrated monograph which is soon to appear. 

 The object of the present preliminary notice is to call attention to 

 some of the more striking characteristics of this curious animal. 



The American species of Ancodus present certain constant differ- 

 ences from the European members of the genus. (1) The muzzle 

 is not drawn out into such an extraordinary rostrum ; (2) The skull 

 has greater vertical height, though this difference may be due in 

 part to the crushing which the Ronzon specimens have undergone ; 

 (3) The corotioid process of the lower jaw is much more prominent 

 and more decidedly recurved. 



The structure of the cranium is very similar to that found in the 

 peculiar American genus, Oreodon, the proportions of the cranial 

 bones being nearly identical ; but while in Ancodus the facial region 

 is remarkably elongate, in Oreodon it is extremely short, the teeth 

 forming a continuous series without diastemata. 



The vertebral column is also oreodont in character, and the odontoid 

 process of the axis, as in that family, is neither conical nor spout- 

 like, but half way between the two. The ribs are long and broader 

 and more flattened than in the oreodonts, and the sternum is similar 

 to that of the latter family. The scapula, humerus, ulna, and radius 

 differ from those of the oreodonts only in detail ; thus the ulna is 

 less reduced and has a shorter and remarkably heavy olecranon. 



The manus is pentadactyl, with a large, well-developed pollex. 



