AND AVES OF NORTH AMERICA. 



71 



In. Lin. 

 1 5. 



Measurements of Vertebra). 

 Of Young. 

 Eighth? dorsal; total length, 



length to shoulder, 



longitudinal line between zygapophyses, 

 horizontal base of neural spine, 

 depth of neural canal, 

 " " articular cup, 

 width of 



neural suture to nearest diapophysis-, 

 Thiid?lumbar; total length, 



length to shoulder, 



longitud. line between zygapophyses, 

 horizontal base of neural spine, 

 depth neural oanal, 

 " articular cup, 

 width 

 First sacral ; length, 



anterior width centrum, 

 posterior " " 



depth neural oanal, 



" artioulation of diapophysis, 

 length " 



width neural arch between diapophyses, 

 Anterior caudal ; length, 



" to shoulder, 

 depth neural oanal, 

 " articular cup, 

 width " " 



width inferior plane, 

 Distal caudal ; length, 



" to shoulder, 

 depth cup,* 

 width " 

 length base diapophysis, 



None ..I' the vertebras exhibit a constriction of the neural canal by a ridge on each of its sides, as is seen in the 11. 



tenebrosus. 



This specimen is named from the short longitudinal and vertical extent of its hypapophyses. 



A. right humerus acoompanying three vertebras of the adult, has the same color and mineralization, and was 

 found with them ; it probably belongs to the same animal. Compared with a humerus of H. obscurus of medium 

 wze, it is three-fifths the length and has more strongly marked articular faoes. The head is more fcran«ver#e, less 



founded, and more strongly divided info the scapular and eoracoid faces. The width of the head is one fourth the 

 length, and reaches the summit of the deltoid crest. This crest is lower down in II. obscurus. (he above width only 



reaching its proximal base. The anterior face above the crest is concave in H. brevispinis, nearly Hat in II. obscurus. 

 There Is a moderate infernal tuberosity distally, and the condyles are moderately prominent, Coronoid fossa well 

 marked. 



1 



1. 



1 



5.5 





11. 





4.5 





9.5 





9.5 





3. 



1 



5. 



1 



1. 



1 



<;. 



1 







4.75 





i). 





11. 



1. 



2.75 



1 



.75 





10. 





4.75 





11. 





9. 



1 



2.5 



1 



5. 



1 



1.5 





4.5 





8. 





8.75 





4. 



1 



5.5 



1 



3.25 





0. 





5. 





3.75 



* Measurements of the artioular cup arc always mail.' from middle to middle of the rim. 



