ANATOMY OF VERTEBRATES. 



131 



giilar,' fig. 92, 29 ; of an ' angular ' continued into a ' splenial,' ib. 30 ; 

 of a ' coronoid,' ib. 29' ; and of a ' dentary,' ib. 32. All Chelonia 

 are edentulou.s : the alveolar borders of both upper and lower 

 jaws are sbeatlied with horn : Init in a few species, especially the 

 soft turtles ( Triontjx, Tetronyx) these borders are notched or pro- 

 duced into tooth-like processes. The dentary elements coalesce 

 at the symphysis ; which, in the Snappers, especially Chehjdra 

 (^Chehnura) Temndnchii, is produced into a sharp hook. 



Tlie liyoid arch consists of a basihyal, fig. 92, 41, a pair of short 





Side view of cninial vcrtelu-a\ Enujs 



processes, ib. e, giving attachment to the genio- and hyo-glossi 

 muscles : of a pair of long ceratohyals, 40, by which the arch is 

 suspended to the mastoids ; and of a pair of hyobranchials, 47. To 

 complete the series of skull-ljones homologous with those of the 

 fish, represented in fig. 81, it is necessary to bring forward the 

 scapular arch which had receded a short distance from its vertebra 

 in the Batrachia, fig. 42, 52, from a more remote position in the 

 Chelonia : we then find that 51, fig. 92, answers to the scapula, 

 fio-. 81, 51 ; and that 52, fig. 92, answers to the coracoid, fig. 81, 52 : 

 the diverging series of many-jointed rays in the fish, fig. 81, are 

 now developed into the fore-limb, fig. 92, 53 — 5S. 



K 2 



