ON THK STATUS OK CHELONIA DKPliKSSA I'MtY. 181 



assigned it to tlie LCeiius Lepithicltehjs ; but it fails to meet the 

 requirements of this genus, as lie defines it, in having the 

 frontals entei'ing the rim of the orbit." Thus we find this 

 character allowed generic importance although Dr. Boulenger 

 had earlier shown that it was just as variable in the allied 

 Caretta as in the genus Ghelonia. Dr. Hay^^ himself writes : 

 " Boulenger has noted that occasionally in the loggerhead 

 (Careff(i) the frontal on one side or the other enters the rim 

 of the orbit. Doubtless it will be found that sometimes the 

 frontals of the bastard-turtle (Colpocliehjx) are excluded from 

 the orbit ; but such variations hardly affect the specific value 

 of the character." It is indeed remarkable that such a 

 variation should occur in two of the three well-known recent 

 species of turtles, and, that in the two others less perfectlj' 

 studied, the exceptional condition should occur, that in which 

 the frontals do not enter the orbit. With further material it 

 is very probable that not only the generic value (wliich I am 

 not prepared to agree exists) but the specific value of this 

 character will also disappear. 



In C. depreKsa (tig. -iTa) the length of the fronto-parietal 

 suture equals the greatest width of the frontals, but in i\ 

 mijdas the greatest width i.e. the width in the region where the 

 frontal enters the orbital border, is almost half as great again. 

 The greatest length of the frontals in C. mijdas (not their 

 length along the median suture) is also slightly longer. Owing 

 to the broader interorbital region in the common Green Turtle 

 and the extension (generally) of the frontal into the orbital 

 border, they have a very different outline to those of ij. 

 depressa. 



The quadratojugal not infrequently fails to meet the post- 

 frontal in suture in C mydas, and this is the condition of the 

 bones in 0. depressa (fig 48a). I have only seen one example 

 of C. m.ijdas in which the squamosal and jugai come into con- 

 tact, thus separating the two bones, and that, peculiarly, is the 

 specimen lent me by Dr. Kesteven, in which the frontal does not 

 enter the orbital rim. In my smallest specimen (tig. 48b), the 

 quadratojugal and postfrontal meet in suture on both sides, 

 and, as the frontals enter the periphery of the orbits to com- 

 paratively the same extent as in adult specimens, neither of 

 these characters can have anything to do with age, but must 



sn Hay— Proc. U.S. Nat. Mus., xxxiv., 1908, p. 191, 



