PROTOSTEGID^. 



197 



Cope described and figured the humerus and some other limb bones. Case also added to 

 our knowledge of the limbs ; to Wieland most of all we are indebted for their complete restora- 

 tion. The materials furnishing his observations are in the Carnegie Museum, at Pittsburg. 

 The scapula, with its procoracoid process, is a stout bone. The coracoid is so long that it 



reacht the pelvis. The humerus is greatly modified, resem- 

 bling in some respects that of Dermochelys. The fingers are 

 elongated to form a great paddle for beating the sea. The 

 length of this limb, from the glenoid cavity to the tip of the third 

 finger, is estimated by Wieland as being 1060 mm. The greatest 

 spread of the fore limbs is supposed to have been 2500 mm. For 

 details on the structure of the flippers the student is referred 

 to Wieland's paper and to the figure here presented (fig. 251). 

 Fig. 252, reduced from Wieland's paper, represents a 

 humerus of Protostega now in Carnegie Museum. The total 

 length is 340 mm. 



Fig. 253, taken from Wieland, represents the hinder limb 

 and the pelvis. Both the pelvis and the limb resemble closely 

 those of the Cheloniidae. The ilium is a stout bone. The 

 ischium and the pubis appear to have met on the midline. The 

 hinder limb, in comparison with the fore limb, is relatively 

 longer than it is in most Cheloniidae. The greatest spread of 

 the hinder flippers is given as 1900 mm. Wieland thinks that 

 four of the toes were clawed. 



Estimates varying greatly have been made regarding the 

 size of this sea-turtle. It is highly probable that earlier esti- 

 mates made by Cope and Hay were too great. Cope concluded 

 that his specimen had a total length of 12.83 feet, about 3900 

 mm. From the specimen studied by Hay about the same con- 

 clusion was reacht. The discovery by Case that the plastron 

 was much shortened behind caused him to conclude that the 

 total length was considerably less than had been supposed. He estimated the length, including 

 the head, as about 2270 mm. He made the length of the carapace as 1640 mm., the width as 

 1235 mm. However, if we may judge from the carapace described by Wieland, the width 



FIG. 252. Protostega 

 Humerus. Xi. 



e, ectepicondylar passage. 



g'g a 



FlG. 253. Protostega gigas. Pelvis and hinder limb. X&. 



astc, astragalo-calcaneum; fern, femur; fb, fibula; I-V, the digits; il, ilium; isch, ischium; met, metatarsals; 

 p, first row of phalanges ; pub, pubis ; lib, tibia ; 1-5, tarsals of second row. 



was considerably greater than the length. It is now estimated that the length of the carapace 

 of the Pittsburg specimen was about noo mm. and the width about I20O mm. The total 

 length of the animal then must have been perhaps something over 2 meters. Its humerus 

 was 340 mm. long; that of Cope's type, 300 mm. 



