Merriam.1 



Neiv IcMhyosauria . 



255 



be determined the clavicles are much like those of Shastasaurus 

 alexandrce and osmonti. 



An elongated, triangular bar, shaped somewhat like a boom- 

 erang, stretches across the median line below the contact of the 

 clavicles and possibly represents the interclavicle (PI. 21, fig. 1, 

 Ic and Ic') . One-half of the triangle is perfectly preserved. The 

 angle on the other side has been broken away, but had probably 

 a form similar to the part present. The obtuse angle on the 

 convex side of the bone may represent the median stem of the 

 interclavicle in Ichthyosaurus. If this element is entire the 

 posterior angle or median stem is much more reduced than in 



auy other known Ichthyosaurian. 



Measurements. 



Coraeoid 



Antero - posterior diameter 72 mm. 



Transverse diameter 35 



Greatest thickness at proximal end 12.5 



Greatest thickness on distal margin 15 



Scapula 



Length 40 



Thickness at proximal end 1 1 



Width at proximal end *19 



Clavicle 



Width at end next median line 16 



Width in middle of shaft 1 1 



Anterior limbs (PI. 22, fig. 1). — In agreement with the gen- 

 erally elongated type of the limb, the humerus is considerably 

 longer than broad. The distal end is wider than the proximal, 

 having a transverse diameter equalling two-thirds the length of 

 the bone. The trend of the anterior border is nearly at right 

 angles to that of the distal margin, while the posterior border 

 slopes backward. This means that the posterior side of the limb 

 would receive a little less power than the anterior side, a fact 

 that might have some influence in determining the location of 

 reduction in the phalangial portion of the limb. In the middle 

 of the anterior margin is a sharply cut notch which is opposite 

 the deepest part of a much broader indentation of the posterior 

 side. This constriction of the middle of the humerus clearly 

 represents the original shaft of the bone. Its presence here 



*Approximate. 



