180 RECORDS OF TUE AUSTRALIAN MUSEUM. 



The frontals in ( '. deprt'sna (fig. 47a) do not enter into the foi-- 

 mation of the upper border of the orbits. In all but one of the 

 examples of C. mydas available to me, they do. In one specimen, 

 however, lent me by Dr. Kesteven,27 the prae and postfrontals 

 meet in suture laterally excluding the frontal completely on 

 each side from the orbital rim. This variation, which is 

 certainly tlie exception rather than the rule, has been recorded 

 by Dr. G. A. Boulenger^^ who has noticed it in both ( '. iin/das 

 and Caretta caretta. He lecords that in one specimen of C. 

 )iii/d(is "the prae and postfrontal bones were in contact, 

 excluding the frontal from the periphery of the orbit ; in 

 another the frontal separated the praefrontal from the })ost- 

 frontal ; whilst in a third, the former disposition was shown 

 on the right side and the latter on the left."-^ This character 

 has, b}' Dr. George Baur^o and Dr. O. P. Hay-^^ been allowed 

 genei'ic value, but with peculiar inconsistency on the part of 

 the former author. He chai-acterises the genus Chelotiin as 

 having the " orbit formed by : prefrontal, frontal, postfronto- 

 orbital, jugal, maxilliary." Just below this definition how- 

 ever, he overlooks its generic value and unites ColpocheJijs, 

 Garman, in which the frontals enter the orbital rim, with 

 Lepidochehjs, Fitzinger, in which the orbit is described as 

 being bounded by the " prefrontal, postfronto-orbital, jugal, 

 maxilliary." Dr. Hay-^"'^ in his fine Monograph of the " Fossil 

 Turtles of North America " recognises CoIpocheJi/s as 

 synonymous with Lepidochelys after Dr. Baur, but later stilP^ 

 he regards it as distinct. He remarks^* " Baur again 

 referred to this species (CoJixicJudijn Icemini) in 1890 and 



'^"^ This specimen was obtained from an hotel in Sydney and the 

 locality is unknown. No record of its shield characters have been kept 

 so that it is necessary to pi'esume that it was otherwise identical with 

 C. mydas. It is a coincidence too. that in this specimen the jugal meets 

 the squamosal in suture as mentioned anlc p. 181, an e.x;cei)tional 

 condition. 



28 Boulenger— Proc, Zool. Soc, 1890 (1891), p. 618. 



29 Hay— Proc. U.S. Nat. Mus., xxxiv., 1908, p. 196, records this last 

 condition in Caretta remivaga, sp. nov. 



30 Baur— Amer. Nat., xxiv., 1890, p. 486. 



31 Hay— Proc. U.S. Nat. Mus., xxxiv., UK)8, p. 183. 



•'- Hay — Foss. Turtles N. Amer., Cai-negie Inst., pub. 75., 1908, p. 8-10 

 and 16. 



33 Hay— Proc. U.S. Nat. Mus., xxxiv., 1908, p. 194. 

 3-» Hay— Proc. U.S. Nat. Mus., xxxiv., 1908, p. 184. 



