CHELONIA M ARM GRATA. 455 



But whether 



Chelonia lacrymata, Cuv. R6gn. anim. 2(i ed. II, 1829, 13 ; &, ed. illustr. Kept. 19, 



is identical with it, we are not, for the present, prepared to decide, 



3. Chelonia marmorata, Dum. & Bibr. 



(Plate XXXI, figs. 5-7.) 



Spec. Char. — Head rather small ; vertex plate small ; middle occi- 

 pital large ; postoccipitals moderate. Lowermost and third post- 

 orbitals larger than the second and uppermost ; the second occa- 

 sionally subdivided so as to give five postorbital plates. Upper 

 temporal shield moderate, subequal with the rest, which are smallest 

 over the tympanum. Carapax subovate, elongated; back quite 

 arched or convex. Middle vertebral shields longer than broad. 

 Marginal shields rather large, twenty-five in number. 



^YN.— Chelonia marmorata, DuM. & Bibr. Erpet. gen. II, 1835, 546. PI. xxiir, 

 fig. 1. 



Chelonia midas, Shaw, Geu. Zool. 1X1, i, 1802, 3. Tab. xxii. 



Observ. — This species is here introduced for the sake of compari- 

 son with the following one, in order that a certain series of characters 

 of both could be satisfactorily shown. Space did not permit giving 

 a figure of the carapax on the accompanying Atlas. In its outline it 

 difiers widely from that of 0. formosa; it is more of a subelliptical 

 form, the back being more arched, the sides steeper, and the periphery 

 more declivous. The shape of the epidermic shields vary in the same 

 proportion, since their absolute number is the same in both species ; 

 the middle dorsal ones are longer than broad. 



The head is a good deal smaller than in G. formosa, and the cepha- 

 lic plates, though of a similar type, exhibit various modifications cha- 

 racteristic in either species. The middle occipital, hexagonal in shape, 

 is the most conspicuous ; the postoccipitals, subtrapezoid, come next, 

 then the elongated frontals, the subpentagonal parietals, and the irre- 

 gular latero-occipitals. The vertex plate is the smallest, pentagonal, 

 narrow posteriorly, and angular in front. There are a few supple- 



