17 



March 11, 1834. 

 VVilliam Spence, Esq., in the Chair. 



Specimens and drawings were exhibited of a freshivater Torloise, 

 foiming pait of the collection of Mr. Bell, by whom it was described 

 as the type of a new genus, for which he proposed the name of 

 Cyclemys. 



Sternum latum, testam dorsalem longitudine fere aeąuans, inte- 

 grum, solidum ; testae dorsali ligamento squamato connexura. 



Cyclemys okbiculata. Cycl. iestd suborbiculari, carinatd, postici 

 dentatd,fuscd; scutis sterili Jlavescentibus, fusco radiatim lineatis. 



Long. dorsi, 8 unc. j iat. 7 ; alt. 3. 



Emys orbiculata, Bell. 



Pūlius. Emys Dhor, Gray, Syn. Rept., p. 20.? 



Hab. in India. 



Mr. Bell regards the Torloise which he has thus characterized as 

 supplying a link in the connecting series of the land with the/res/j- 

 wnter families vvhich has hitherto been \vanting ; and as especially 

 valuable in the natūrai arrangement, by the clue vvhich it furnishes 

 to the correct locaiion of the Indian forms of the genus Emys. It is, 

 indeed, most nearly related to Eviys spinosa, and on a superficiai ob- 

 servation might almost be referred to that species ; but on closer 

 examination it is found to differ from that Torloise, not only specifi- 

 cally, but generically also : its sternal bones are permanently sepa- 

 rated from the dorsal ones, with which they are connected by means 

 of a ligament alone, similar to that vvhich performs the šame office in 

 Terrapene. From the Box- Tortoises, however, to which, in this point 

 of its structure, it is so closely related, Cyclemys is altogether distinct, 

 the whole of its sternum being entire, instead of having, as is invari- 

 ably the case in Terrapene, one or more transverse divisions of the 

 sternum itself, the lobes of vvhich movė as on a hinge. In Terr. 

 Europcea this mobility of the sternum exists in each lobe in a small 

 degree, combined with the ligamentous connexion of the sternal to 

 the dorsal bones. In Cyclemys the vvhole sternum movės together. 

 thongh very slightly. 



The transition from the land to the Jreshwater Tortoises may con- 

 sequently be regarded as commencing in Terrapene j passing through 

 Terr. Europcea to Cyclemys orbiculata ; and thence through the In- 

 dian forms of Emys, vvhich so closely resemble the latter species, to 

 the other forms of Emys : the natūrai series of conne.xion betvveen the 

 Testudinida and the Emydidco being thus completed. 



The exhibition was resumed of the nevv species of Shells contained 

 in the collection of Mr. Cuming. Those novv exhibited vvere accom- 

 No. XV. Proceedings of the Zoological Society. 



