322 



ZOOLOGY 



SECT. 



ten in number, are immovably united with one another by means 

 of fibro-cartilaginous intervertebral discs. Each of the neural 



FIG. 929. Anterior vertebrae of young Crocodile. A. atlas ; Ep, axis ; IS, inter-vertebral 

 discs ; 0, pro-atlas ; Ob, neural arches ; Po, odontoid process ; Ps, spinous processes ; Pt, 

 transverse processes ; R. R. 1 .R. 2 ribs ; S. arch of atlas ; u. median piece of atlas ; WK, centra. 

 (From Wiedersheim.) 



FIG. 930. Cistudo lutaria. Skeleton seen from below ; the plastron has been removed and 

 is represented on one side. C. costal plate ; Co. coracoid ; e. entoplastron ; Ep. epiplastron ; 

 F. fibula ; Fe. femur ; H. humerus ; II. ilium ; Is. ischium ; M. marginal plates ; Nu. nuchal 

 plate ; Pb. pubis ; Pro. procoracoid ; Py. pygal plates ; R. radius ; Sc. scapula ; T. tibia ; 

 U. ulna. (From Zittel.) 



spines, from the second to the ninth inclusively, is expanded into 

 a flat plate, and the row of neural plates (Fig. 931, F), thus formed, 

 constitutes the median portion of the carapace. The ribs 



