38 CHELODINA. 



The shell is roundish, rather convex ; the sternum is 

 broad, rounded before, bifid behind. The front lobe (and 

 sometimes the hinder one, according to Daudin) is separated 

 from and moveable on the central lobe by a transverse carti- 

 laginous suture. The suture of the front lobe is placed be- 

 tween the pectoral and abdominal plates, and the front lobe 

 is furnished with an iViternal bony process on each side, near 

 the suture, serving as a hinge. The intergular plate is in the 

 margin, between the gular plates ; the margin is destitute 

 of any nuchal plate ; the lateral marginal plates are very 

 narrow, and the two front ones are very short and square. 

 The inner surface of the hinder lobe of the sternum, in the 

 specimens which I have examined, is marked with the scar 

 of the attachment of the pubis. 



This genus consists of only part of the species of the genus 

 established under the above name by Mr. Bell ; the other 

 species belonging to the family of Emydce. 



1. Ster7iotherus castaneus, fChesnut Sternotherus.) — Testa 

 ovata convexa acute carinata castanea, scutellis nigris levis- 

 simis radiantibus radiatim rugosis ; areolis punctulatis rugosis. 



Emys castanea, Schweiger. Testudo siibnigra, (5. Daud. 

 (v. t. Mus. Par.) Sternotherus Leachianus, Bell Zool. Jour. iii. 

 t. 14, (v. t. Mus. Bell.) 



Habit. (v.t. Mus. Bell et Paris.) 



2. Sternotherus sulniger , [Black Sternotherus.) "Testaovali 

 convexa, scutellis nigris nitentibus in margine striatis ; verte- 

 bralibus mediis planis leviter carinatis." 



Test, siibnigra. Lacep. Daud. t. 7, f. 2. Test, nigricans, 

 Merrem. Emys suhnigra, Schw. 



Hab. (non vidi.) 



This species scarcely appears distinct from the former ; I 

 did not observe it at Paris, and have therefore given Schwei • 

 ger's specific character. According to Daudin the hinder 

 lobe of the sternum is mobile ; but that may be a variety of 

 age. This character is not noticed by Schweiger. 



Gen. 2. CHELODINA, [Chelodina.) 



Maxillae cornese, sternum latum solidum, scutellum inter- 

 gulare hexagon um inter angulos scutellorum gulariura hume- 

 raUumque, nuchale distinctum. 



