6 Watsu^, T//C ['/>/>cr Liass/c J^f/>ri//,r. 



but I could not determine the presence of the super- 

 numerary post-axial bone. 



The femur is rather more slender than the humerus, 

 its anterior border is slightly concave. 



The fore limb o^ Microcleidiis Jioinalospondyliis is known 

 from L. 7077 in the Manchester Museum, the specimen of 

 which I have already described the girdles. 



The humerus is 39 cms. long and 21 cms. across the 

 distal end : the anterior border of the bone is straight, the 

 posterior strongly concave, the distal end shews two facets, 

 inclined to one another at an angle of about 135", there is 

 also a post-axial facet of small size and somewhat rounded. 

 The head is set straight on the shaft, it is a rounded knob 

 8 cms. in diameter, pitted all over for a cartilaginous coat, 

 with it is confluent the pitted surface of the great tuber- 

 osity, vv'hich has an area of 6 cms. by 4 cms. ; this tuberosity 

 gradually subsides on to the shaft. 



The radius and ulna resemble exceedingly those of 

 M. macropteriis, they are of equal length, the post-axial 

 supernumerary ossicle of the other species was probably 

 originally present, although it is not preserved. 



The radiale, intermedium, ulnare, and pisiform are 

 exactly as in M. inacropterus, except that the distal point 

 of the intermedium is truncated and articulates with a 

 small triangular bone completely surrounded by the inter- 

 medium, and the second and third distal carpalia ; this 

 extra bone occurs in no other known Plesiosaur limb, and 

 may be an individual abnormality ; in any case, it may 

 represent one of the centralia which must have occurred 

 in the ancestors of the Plesiosaurs. 



Another small triangular bone, of which the exact 

 position is unknown, is probably a pre-axial accessory 

 bone similar to that figured by Fraas in the fore limb of 



