PROTOSTEGIDJE. 



207 



being 465 mm. At the hinder end of the symphysis its depth is no mm., and the width of 

 the jaw, 155 mm. On the under surface the symphysial end of the jaw turns strongly upward, 

 but the upper surface rises little. Wieland found the splenial to be present. 



Wieland has described 5 cervical vertebrae (fig. 266, cer. v) which belonged to the type 

 specimen (Amer. Jour. Sci., n, p. 401; xiv, p. 102). These centra indicate a neck of great 

 strength. The centrum of one, regarded as the third or the fourth, is procoelous, 95 mm. long 

 and 140 mm. wide. Dorsal, sacral, and caudal vertebrae also are described by the same author. 



The shoulder-girdle of the type specimen was described by Wieland (Amer. Jour. Sci., 

 II, p. 404). The scapula (fig. 266, scap) is a stout and heavy bone, resembling that of Pro- 

 tostega. The length of the body of this bone, from the upper end to the glenoid fossa, is 

 450 mm. The coracoid (fig. 266, cor) is elongated and slender, as in Protostega. The length is 

 650 mm., the width of the distal end, 127 mm. 



ul- 



FIG. 267. Archelon ischyros. Limb bones. 



jem 1 , left femur, dorsal surface ; fern", left femur, tibial border ; fern"', proximal end of left femur, fibular border ; 

 fb, fibula ; hum, left humerus ; rad, ulna ; lib, tibia ; ul, radius. The bones marked rad and ul should 

 exchange places, be placed with the other ends up, and eichange explanatory letters. 



The humerus (figs. 266, 267, hum) is an enormous bone, the length from the head being 

 580 mm.; the total length, 650 mm. The width of the distal end is 340 mm. This bone differs 

 from that of Protostega in having a relatively smaller head and the radial process much reduced. 

 Wieland describes also the radius, the ulna, and some phalangeal bones. The figures by 

 Wieland are here reproduced. In the figure of the fore limb the upper ends of the ulna and 



will have the positi 



the radius have mistakenly been represented as the lower. When the ends are reversed they 

 the positions that they have in Wieland's figure of the anterior flipper of Protostega 

 gtgas. The bones must also exchange places and legends. 



The pelvis of the type specimen is described and figured in the journal so often quoted 

 (vol. ix, p. 247). The figure is here reproduced (fig. 268). This pelvis is of astonishing size, 

 the length and the width being each nearly half the length of the carapace. In general, its 



