90 MR. D. M. S. WATSON ON THE 



dorsal surface and right side were published by Seeley, and that 

 author also gave less intelligible figures of the palate and of 

 the much damaged occiput. 



This skull has the lower jaw in position, and except for the loss 

 of the end of the snout appears to be (as are the other bones 

 from the same rocks) very well preserved and undistorted. 



The skull itself is in Russia and quite unreachable, but in the 

 light of our present knowledge of Anomodont structure it is 

 possible by a careful study of the drawings and of Prof. Seeley 's 

 description to gain a clear idea of its more important features. 

 In text-fig. 26 I have drawn four reconstructions of this skull 

 on the indications available. 



For the occiput I have used that figured by von Meyer as 

 Deuterosaurus, which cannot belong to that genus because it is 



Text-figure 27. 



Fen.Ov 



Brain-case of 'Rhopalodon ? 

 Right lateral aspect. X J. 



From a cast in the British Museum of the specimen figured by von Meyer 

 as Deuterosaurus . 



only half the size of that in the skull figured by Seeley, and does 

 not appear to agree at all in structure. It is, on the other hand 

 of very nearly the same size as the occiput of Seeley 's Rhopalodon 

 skull, shows no features incompatible with the wreck of that 

 region in this skull, and must presumably belong either to 

 Rhopalodon or the very similar Deinosaurus. 



Rhopalodon at once recalls the Pelycosaurs in appearance and 

 in certain structural features. It has a high compressed snout 

 passing backward into a square-cut lachrymal region, with a, 

 depression overhung by a projecting ridge on the prefrontal, just 

 as in Dimetrodon. The jugal in its shape at once recalls that of 

 the earlier genus. It differs from Dimetrodon in the much 



