W. C. Knight — Jurassic Vertebrates from Wyoming. 379 



Megalneusaurus rex Knight.* 



The type of this genus and species has been founded upon 

 the following remains : Cervical, dorsal and caudal vertebra ; 

 one limb nearly complete ; ribs and the greater portion of the 

 pectoral girdle. The limb measures 2*209 meters in length. 

 When found it was articulated and in the position represented 

 in figure 1. Between the ends of the phalanges were hardened 

 disks of siliceous matter measuring 10 mm in thickness. The 

 phalanges are long cylindrical bones with rather slender shafts 

 and expanded ends. The shape and size of these bones vary- 

 greatly when belonging to the same row. For example, the 

 first phalange of the first digit is 87 mm long, and the first pha- 

 lange of the fifth digit is 106 mm long. The first digit is coal- 

 esced with the second at the fifth joint of the second. The 

 metacarpal of the fifth digit articulates with the ulnare and the 

 third bone of the distal row of car pals. The radius has a 

 groove extending two-thirds of the length of the exterior 

 border. Radial likewise grooved. The coracoids are long, 

 broad bones, but are not in a condition to give valuable measure- 

 ments. The vertebra vary greatly in form : cervicals, trun- 

 cated above, with nearly straight sides which gradually curve 

 and form a rounded lower surface ; dorsals, cylindrical, slightly 

 compressed, with large transverse processes ; neural spines low 

 and keel shaped ; caudals, flattened beneath. 



Measurements. 



Humerus, — Length . . 



Distal width 



Distal thickness 



Thickness of shaft 



Circumference of shaft 



Proximal width . _ 



Proximal height 



Proximal circumference 



Ulna— Width _ 



Length 



Distal thickness 



Proximal thickness — 



Radius, — Width 



Length 



Distal thickness 



Proximal thickness 



Ulnare, — Width 



Length 



Thickness 



Intermedium, — Width . _ 



Length 



Thickness 



991 m 



365 



122 



195 



555 



225 



266 



875 



1 78 m 



158 



080 



104 



17l m 



163 



100 



100 



130 m 



095 



088 



100 m 



140 



078 



*Cimoliosaurus rex., Science, Oct. 4, 1895, p. 449. 



