12 MB. "W. THEOBALD, JUN., ON THIS 



Cyclemys, Bell. 



The characters of the genus, as giveu by Eell, must be corrected 

 thus: — Sternum divided into two qiiasi-lohes hy a perfectli/ mohile 

 osseous suture corresponding to llic transverse carlilaf/inous suture 

 of Cuora. This osseous suture is formed by the permanent non- 

 union of the pectoral and abdominal bones of the shell, and is 

 most developed in aged specimens, in which it becomes visible 

 externally by a carious fossa traversing the external plates, and 

 which may be noticed faintly in the fig. of the type G. Oldhami in 

 Griinther's ' Hoptilcs of Brit. Ind.' 



C ORBicuLATA, Bell (young), 



C. dentata, Gray (adult). 



C. Oldhami, Gray, P. Z. S. (adult). 



This species was not unjustly regarded by Mr. Bell as a very 

 curious one, and as affording a link between the box-tortoises and 

 tlie more typical Emydidce. Strangely enough, its describer over- 

 looked the fact of its possessing the very curious pseudo-hinge, 

 the bomologue of the ligamentous hinge of Cuora, although in 

 this species the motion of the two portions of the sternum is very 

 limited, owing to its being the result merely of the permanent 

 non-union of the toothed suture of the pectoral and abdominal 

 bony plates, and not of a special ligamentous division. In the 

 very young animal this transverse pseudo-hinge is imperceptible ; 

 but the motion of the plates dcvelopes it as the animal grows, so 

 that in half-grown epecimens it is perceptible enough, and, in 

 adult or aged ones, is often marked externally by a carious fossa. 

 Drs. Gray and Giinther have equally overlooked or misunderstood 

 this peculijirity, though in Giinther's specimen (type of G. Oldhami) 

 it is sufficiently discernible, which specimen was procured alive 

 by myself, and correctly identified by Mr. Blyth, before it Avaa 

 forwarded by Dr. Oldham to the British Museum*. 

 a. Young 3'50 



Shell orbicular, expanded, strongly keeled. Posterior margins 

 strongly toothed. Tail 0-75. Nuchal plate small, squarish. 

 Colour pale olive ; each plate radiately brown-rayed from a large 

 supero-posterior granular umbo. The umbo of the marginal plates 

 postero-marginal. Pupil round, black. Iris greyish yellow, brown- 



* See Gray in Proceedings of Zoological Society, May 12, 18(53, where 

 of Cyclemys he remarks "the lobes are only moveable in the young state." 



