1. Cl.VOSTKRXUM. 



35 



The rib-like process of the nuchal is long and situated beliind 

 the marj^inals iu the young, short and extending below the first 

 marginal in the adult, Jfeural plates narrow, forming an incom- 

 plete series, five or six in number, the two or three last pairs of 

 costals, and sometimes also the first pair, in contact on the median 

 line; eighth costal sometimes (C. odoratum, C. scorpioides) very 

 small, and without distal i)oint. Vertebral and costal shields usually 

 imbricate. Linabs and tail scaleless ; two or three curved lamella) 

 on the front of the forearm, and some on the hinder side of the 

 leg. 



Fig. 12. 



Shell of Cinosfernum leucosfo 



/num. 



Young specimens of all the species are very similar, and their 

 determination meets with great difficulties. There is but a small 

 difference in the size of the plastron between a newly born Cino- 

 sternum of Group 1. of the following synopsis and a corresponding 

 one of Group II., whilst that between the latter and one of Group IV. 

 is quite insignificant, if at all perceptible. The following synopsis 

 of the species applies therefore only to adult specimens. 



It must be borne in mind that, as in all Chelonians with hinged 

 plastral lobes, the mobility does not exist in the quite young spe- 

 cimens, and is often scarcely distinct, or restricted to the front 

 lobe only, iu the halr'grown. 



