554 Mr. R. W. Hooley on the 



the radius rested, bordered postaxially bv the longitudinal 

 ridge. The ventral surface is strongly convex. On the 

 articulation there is clearly visible, although filled with 

 matrix, the circular pit near the preaxial border, for the 

 hemispherical knob of the proximal carpal, and at the post- 

 axial edge on the ventral surface are seen the remains of the 

 facet for articulation with the produced border of the carpal. 

 Distally no. 2 is very much inflated. 



J. a. 10, 3 : the distal end of left ulna. The surface for 

 the radius is more concave and the ridge more developed 

 than in no. 1. The dorsal surface becomes flatter proxi- 

 raaliy, while in nos. 1, 2, and 9 it is gently convex. The 

 distal extremity of this example differs considerably from 

 no. 1 ; instead of being strongly inflated, both dorsal and 

 ventral surfaces are fiat, converging and forming an angle 

 on the preaxial border. Nos. 4, 7, 8, and 11 are examples of 

 this type. J. a. 10, 6, the distal eud of left ulna, has a very 

 inflated convex ventral surface, continued to the articulation. 

 The longitudinal ridge is moderately developed. The dorsal 

 articular surface for the radius is slightly concave. The 

 preaxial side of the articulation is not as inflated as no. I 

 nor as compressed and angular as no. 3. Nos. 5 and 10 are 

 examples of this type. 



No pneumatic foramina are to be found on any of these 

 specimens. 



Conclusions as to the Extremities of Ulnce (see pp. 552-553). 



By a comparison of the articulatory surfaces of J. a. 11, 

 1, 2, 3, 4, 5, and 6, it is quite possible that they belong to 

 species with the same type of the distal end of humerus as 

 nos. 21 and 32 on tablet J. a. 6, and therefore of Group A. 

 Granting that the proximal ends, J. a. 9, 2, 3, 4, 5, and G, 

 Gi'oup B, have lost no epiphysis, and are as they were in 

 life, we consider them to belong to the same reptiles, 

 possessing the type of humerus exemplified in tiie distal eud 

 of humerus J. a. G, 20, Group B, a}id thus, if our conclusions 

 are correct, to Oraitliostoma. 



The only distal ends of humeri that J. a. 9, 1, Group C, 

 could in any way articulate with are those of the Group C, 

 of which the humerus J. a. 6, 30 is the type. The proximal 

 end of the ulna J. a. 11, 7 must for the present remain an 

 isolated bone, necessitating the formation of Group D, of 

 which it is the only example. 



There is no evidence available to enable the apportionment 

 of any of the distal ends to either of the genera formed by 



