20 CHELONIA. 



emarginate above the neck, and has a small, deep notch above the tail. The sternum is 

 truncated anteriorly and deeply notched posteriorly ; its mdth between the front incisions 

 equals that between the hinder, and is less than one-half of the length of the sternum. 



Plates. — Areolae and concentric striae very indistinct. Nuchal plate short, triangular. First 

 vertebral urn-shaped ; second rather broader than long ; third as broad as long ; fourth and 

 fifth with the keel rather prominent, the latter broader than the caudal. Caudal divided 

 into two by a very distinct groove. Marginal plates without any spines in large specimens. 

 Gulars as long as broad, the sum of their posterior angles being equal to a right angle ; 

 postgulars and pectorals of equal length ; abdominals broader than long ; prseanals as broad 

 as long ; anals rhombic, their inner margins forming a suture together and being shorter than 

 the posterior ; the angle of the notch between the posterior margins is nearly a right one. 



This description is taken from the typical specimen of Geoemyda grandis, a very old 

 male from Gamboja, 17 inches long, with a concave sternum. An apparently full-grown 

 female from the same locality, 11 inches long, differs considerably in the form of the shell ; 

 but there cannot be any doubt that it belongs to the same species, having the same cha- 

 racteristic coloration of the sternum and the same non-serrated anterior margin of the upper 

 shell. The shell of this specimen is much depressed, ovate, its greatest depth being con- 

 siderably less than the width of the sternum. As it is much younger than the male, the 

 areolae and concentric striae are very distinct. Nuchal plate elongate, triangular; sternal 

 portion of the abdominal nearly square. 



M. Mouhot, who collected these two specimens in Gamboja, has sent at the same time 

 a third, only 3 inches long, with the shell much shrivelled in consequence of its soft con- 

 dition in a fresh state. The ai'eolae are proportionally very large, granulated, and surrounded 

 by only two concentric striae. The most interesting point in the structure of its shell is, that 

 each vertebral plate, except the first, is di\ided into two lateral halves, which are arranged 

 in a zigzag line, each half overlapping the longitudinal ridge with its inner angle. Remains 

 of this structure are sometimes indicated in old specimens of G. sjn'nosa and of Cyclemys. 



Head, tail, feet, and coloration the same as in Geoemyda spinosa. 



The male specimen in the British Museum bears such evident signs of very old age, that 

 we do not believe the species grows to a larger size than from 17 to 18 inches. 



Plate I. represents the typical specimen, a full-grown male, one-thu'd of the natural size ; 

 figs. A, A', A" of Plate II., an adult female, also one-third, and figs. B & B' the young, one- 

 half of the natural size. 



