96 



University of California. 



[Vol. 3 



The anterior limbs of osmonti have been described in detail in 

 the general discussion of the genus. As yet they are the only 

 known bones representing the anterior limbs of this genus, except 

 the fragment of a humerus with the specimen of alexandrce. The 

 humerus of osmonti differs from that of alexandrce in being much 

 thicker and in possessing a much narrower notch in the anterior 

 border. 



osmonti. alexandrce. 



Humerus 



Greatest axial length .170 al90 



Width of distal end 180 



Greatest thickness proximal end 80 68 



Thickness distal end 50 38 



Width of anterior notch 10-20 40 



Radius 



Length 95 



Width 115 



Thickness of proximal end 50 



Ulna 



Length 71 



Thickness of proximal end 30 



Eadiale 



Width 95 



Thickness of proximal end 30 



Shastasaurus alexandrae, n. sp. 



Pls. 12 and 13. 



This species is represented by a specimen collected a quarter 

 of a mile south of the Cove by the party under Mr. H. W. 

 Furlong. It was found a short distance below the contact between 

 the Atractites beds and the Trachyceras beds. The specimen 

 includes the greater part of a skull, nearly all of the pectoral 

 girdle, part of a humerus, fifteen or sixteen vertebra? belonging 

 to the anterior portion of the column, and numerous ribs. 



The cranium has already been described in detail as the only 

 one certainly known to belong to a member of this genus. It is 

 essentially like that of Ichthyosaurus. The portion of a humerus 

 which is present shows that element to have been much thinner 

 at both extremities than in osmonti. The anterior notch is also 

 very different, being much wider and relatively shallower. 



The coracoids like the humerus are thinner at both extrem- 

 ities than in osmonti and are much wider distally. The anterior 



a Approximate. 



