464 H. G. SEELEY ON THE AXIS OE A WEALDEN DINOSAUR. 



there are two lateral articular surfaces wider apart, but not entirely 

 incomparable with the articulations in the Dinosaur. The resem- 

 blance is almost as close to the axis of Hatteria, though in that genus 

 the neural spine is large, and there are no lateral articulations for a 

 cervical rib, a resemblance the more important since this ordinal 

 type links itself closely with the Chelonia and Crocodilia. In the 

 Crocodile the axis has a two-headed rib, but the odontoid process is 

 not anchylosed to its flat anterior face, while its posterior face is as 

 unlike that of the Dinosaur as is the corresponding surface of the 

 axis in a bird. Among mammals the nearest resemblance to this 

 bone is seen in the whale. 



I gratefully express my indebtedness to Prof. Hughes for the 

 loan of this specimen. 



Discussion. 



Prof. Leidt remarked that, although he had never seen the axis 

 of a Dinosaur, the type of vertebra described was so like that of the 

 succeeding ccrvicals of the genus Hadrosaurm, that he had no doubt 

 the author was correct in his identification of it. 



