50 NORTH AlvrERirAN BATRAOIIIA AND KEPTILIA. 



h. Shield coiiipletelj ossified. 



X. Fingers and toes not bound closely together ; more 

 than the distal phalanges free. 



*Tail crested, very long and strong; plastron 

 narrow and small; bony vertebral plates 12, 

 continuous the whole length of carapace; 

 plates of plastron nine; head large; neck long 

 and stout ; body highest in front . . ChelydridcB. 

 **Tail short ; plastron usually broad and large. 



1. Lower jaw with a long, strong, sharp point 

 at symphysis ; bony vertebral plates from 5-7, 

 not continuous; plates of plastron eight in 

 adult ; iliac bones arched outwards ; coracoids 

 reaching back of middle transverse suture of 

 plastron; coracoid and pubis closely approxi- 

 mated; skin loose on knees and elbows; tail 

 tipped with a horny spur in males. 



CinosternidcB. 



2. Lower jaw without long point at symphysis ; 

 bony vertebral plates 10, continuous; plates of 

 plastron nine ; iliac bones nearly parallel ; cor- 

 acoid not reaching middle transverse suture; 

 skin clinging more or less to knees and elbows. 



Mnydidce. 



y. Fingers and toes bound 'closely together; only the 



last joint free; bony vertebral plates about 10; 



plates of plastron nine ; iliac bones wider apart at 



hip joints than at sacrum Testudinidce. 



Family SPHARGIDIDJE. 



Body highest in front and widest at the anterior edge of the 

 bridge; posterior limbs much exposed; head high, short and very 

 broad at the back; two pits and two teeth-like projections on the 

 upper jaw; a single, median projection on the lower. There is 

 but one genus in the family. 



Genus Sfhargis, Merrem. 



Body covered by a smooth coriaceous skin; feet without 

 nails; several longitudinal ridges along carapace. 



94. 8. Goriaoea^ Rondelet. Leathery Turtle. Color above 

 dark brown; below whitish; nodules along the longitudinal 

 ridges of carapace. On the Atlantic coast to Massachusetts, 



