G. R. Wieland — Archelon isohyros. 



40a 



ischyros bears an elongate ridge jnst opposite the coracoid bor- 

 der. The scapula and procoracoid stand at the same angle of 

 125° in both cases. Distallj, both these elements are subtri- 

 angular in section, with the vertices well on the inner side, 

 leaving the inner faces somewhat ridged distally, though medi- 

 ally there is very distinct flattening. 



The outline of the articular face is approximately that of 

 an isosceles trapezoid, with a broadly saddle-shaped convexity 

 angling across it so as to leave on the one side of the upper 

 and wider end of the articular face a concavity for the recep- 

 tion of the coracoid, and on the other side a broad, rather flat, 

 humeral expanse. The entire articulating surface, like that of 

 the coracoid, is tuberculated. The lateral surfaces are finely 

 striate, the procoracoid having additional large striations, like 

 those of the coracoid. 



Measurements of Procoracoscapida. 



Width of neck 



Width of articular extremity 



The greatest transverse width of same 



Length of precoracoid to inferior border of the 



scapula - 



Length of scapula to inferior border of the 



precoracoid . _ _ 



Length of the scapula to the glenoid cavity 



Distance between extremities of the scapula 



and precoracoid _ _ 



Width of precoracoid proximally 



Least width of precoracoid , 



Distal width of precoracoid 



Distal thick^ness of precoracoid 



Least width of scapula 



Proximal thickness of scapula ._ 



Distal width of scapula ._ 



Distal thickness of scapula 



Meters. 

 171 

 21 

 13 



35 



485 

 45 



66 

 117 

 107 

 127 



10 



078 

 046 

 095 

 085 



Humerus. — The humerus agrees with that of gigas in that 

 it is flat, with a heavy globular head and an immense trochan- 

 ter, which, with its base, is even larger than the head. In 

 fact, though the head possesses a large articular surface, its 

 general aspect is that of being a secondary projection from 

 the trochanter. From the massive proximal end the shaft 

 constricts slightly near the middle, at the same time flatten- 

 ing, but again expanding and thickening in the lower half 

 into a flat, but massive, fan-shaped distal extremity, making 

 an angle of about 105° with the proximal end. The most 

 notable variation from gigas (also tuber osa),"^ aside from dis- 



* Cretaceous Yertebrata of the "West, p. 113. 



