110 



Baron F. Xfopcsa — British Dinosaurs- 



bones ; a second individual, of which the distal end of the pubis and 

 some dermal plates have been described by von Huene as Stegosaurus 

 sp., 1 is in the Sedgwick Museum at Cambridge. 



The type-specimen of St. prisons is represented by the following 

 material : 2 anterior cervical vertebras including the axis, 9 dorsal 

 vertebras or fragments of such, 15 caudal vertebrae, 1 cervical rib, 

 fragments of chevron bones, 3 left and 1 right dorsal ribs, the 

 right humerus and ulna, the left femur and parts of the corresponding 

 tibia and fibula, carpal bone, astragalus, and calcaneum, fragments of 

 both ilia, parts of both pubic and ischiac bones, parts of the dermal 

 armour. 



FlG. 1. a. Axis of St. prisms seen from the right (most of the neural spine 

 wanting). b. Anterior cervical rib of same. c. Dorsal vertebra of the 

 same. d. Middle caudal vertebra of the same. 



Vertelrce. — The axis of the Fletton Dinosaur is of special interest, for 

 hitherto no axis of a Stegosaurian has ever been described or figured. 

 It is 12 cm. long; at the posterior end its body is 4-8 cm. wide and 

 4-5 cm. high. Unfortunately the neural arch is much mutilated, as 

 shown in Fig. la. 



The odontoid projects far forward; the centrum is strongly compressed 

 laterally, but as shown by the irregular split-like section of the neural 

 canal this is to some degree due to post-mortem deformation. This 

 deformation has also caused the basal keel of the centrum to be more 



1 Centralblatt fur Mineralogie, Geologie, und Palaeontologie, Stuttgart, 1902. 



