4 Watson, The Upper Liassk Rcptilia. 



its pelvic girdle and that of the Manchester specimen, 

 L. 7077, of y]/. Jioiiialospo}idylus may be accounted for. 



All four limbs of the type specimen of M. macrop- 

 teriis are preserved, and although they are somewhat 

 difficult to make out on account of the imperfect 

 development of the specimen, do give an accurate idea 

 of the structure of the Microcleidus limb. 



For comparison with them there is only the fore limb 

 of M. Jiouialospotidylns at Manchester, which is described 

 later on in this paper. 



The right limb of M, iiiacyopterus^ which is the better 

 preserved, is somewhat obscured by matrix, and has a 

 fracture running across the middle of the shaft of the 

 humerus. 



The dimensions of the humerus are : — length 30 cms., 

 breadth across the head 1 1 cms., across the distal end 

 18 cms., minimum width of shaft 9 cms.? 



The head is obscured, the distal end of the bone has 

 the usual flattened form. The anterior border is almost 

 straight, the posterior is strongly concave. The distal 

 end of the bone presents three facets for other bones. 

 Those for the ulna and radius are straight, nearly in the 

 same line, and approximately at right angles to the 

 anterior border of the bone. The third is smaller, and is 

 parallel to the anterior edge of the bone. It lies on the 

 posterior edge. 



These facets support the following three bones : — 



1st. The radius, a flattened bone 9 cms. across proxi- 

 mally, 13 cms. long and 8 cms. wide distally. Its anterior 

 border is nearly straight, but the posterior border is con- 

 cave, so that the minimum width is only 6 cms. 



2nd. The ulna, which is a flat bone of irregular 

 shape, which will be best understood from Fig. i. 



