TESTT7DINTD.E. 1 13 



R. 1580. A smaller and imperfect left hyoplastral. The anfcero- 

 external angle is wanting, but the entire humero-pectoral 

 sulcus is shown, and is seen to be confined to this bone. 



Hastings Collection, 



30410 e. The right hyoplastral of an immature individual. This 

 specimen agrees in size with the corresponding bone of 

 No. 32349, and shows that the humero-pectoral sulcus 

 traversed the entoplastral, as in that specimen. 



Hastings Collection. 



1L 1577. A nearly similar right hyoplastral. In this specimen the 

 humero-pectoral sulcus would have cut the entoplastral at 

 a higher level than in the preceding specimen. 



Hastings Collection. 



R. 1581. Fragment of a right hypoplastral, agreeing in relative 

 size with the type specimen, and therefore probably refer- 

 able to this species. Hastings Collection. 



30410 f. The left hypoplastral. This specimen agrees with the 

 hypoplastral of No. 32349 in dimensions, its length being 

 0,085 (3*36 inches), and its width at the inguinal notch 

 0,065 (2*55 inches)* It is much shorter than in O. oweni. 



Hastings Collection. 



R. 1578. A right hypoplastral of similar type. Hastings Collection. 



R. 1578 a. A smaller right hypoplastral of the same type. 



Hastings Collection. 



R. 1579. The two associated xiphiplastrals of an individual agreeing 

 in size with No. 32349. The form of the notch is nearly 

 the same as in the latter, and differs widely from that in 

 the type of O. oweni. Hastings Collection. 



The following specimen is from the Upper Eocene {Lower Oligocene) 

 of Apt, near Debruge (Vaucluse), France. 



26651 x. The imperfect left hyoplastral of a young individual. 

 This specimen agrees closely in size with the type plastron 

 of O. oweni, but differs in the contour of the notch for 

 the entoplastral, which is thus shown to have had the 

 wide contour characteristic of the present species. 



Bravard Collection. Purchased, 1852. 



PART III. I 



