CHELONIA FORMOSA. 457 



much longer than broad ; marginal shields moderate, twenty-five 

 in number. Brown, maculated with yellowish or olive. 



DESCR. >The size of the cephalic plates, as given in the above diag- 

 nosis, is comparative with the corresponding ones in C. marmorata, 

 and must be understood as expressing their proportional development 

 in both species. For, if we enumerate those plates in point of abso- 

 lute size in the species which is the subject of the present article, the 

 postoccipitals are the largest of the set ; the middle occipital comes 

 next in order ; then the parietals, the frontals, and finally the latero- 

 occipitals. 



But to return to each of those plates : they differ greatly in form 

 from one another. Thus the frontals are elongated, their sides nearly 

 rectilinear, not to say parallel, for they are somewhat narrower ante- 

 riorly than posteriorly, in conformity with the general outline of the 

 snout, which is obtusely subcouical forwards. A diminutive inter- 

 nasal may be observed at the anterior extremity of the frontal (fron- 

 tonasal) plates, between their commissure. Posteriorly, the frontals 

 are obtusely triangular, the inner edge of that triangle admitting the 

 anterior portion of the vertex plate, whilst the external edge of the 

 same triangle is contiguous to the parietals. The vertex plate is the 

 smallest, subhexagonal, elongated ; narrowest posteriorly, where it 

 emarginates somewhat the anterior edge of the middle occipital; late- 

 rally it is contiguous to the parietals. The latter are a little wider 

 than long, obscurely hexagonal, their exterior edge forming with that 

 of the frontals the upper rim of the orbit. Each parietal is contigu- 

 ous posteriorly to the upper postorbital and anterior latero-occipital, 

 and interiorly to the middle occipital, and as already observed, to the 

 vertex plate itself. The middle occipital is longer than broad, hepta- 

 gonal, posteriorly acute-angled, anteriorly subconcave upon its conti- 

 guity with the vertex plate. Its latero-anterior edges are contiguous 

 to the parietals, laterally to the anterior latero-occipitals, whilst its 

 posterior acute angle engages between the postoccipitals. The latter 

 are quite elongated, sublanceolated, broadest posteriorly, subtruncated 

 behind, and acute-angled in front. Their anterior acute angle engages 

 between the middle occipital and the- anterior latero-occipitals, whilst 

 laterally they are contiguous to the posterior latero-occipitals. The 

 anterior latero-occipitals themselves are obscurely hexagonal, longer 

 than broad, anteriorly contiguous to the middle occipital and the 



115 



