CATALOGUE OF SHIELD REPTILES. 



15 



Synopsis of the Genera. 



A. Head and tail moderate ; sterno-costal suture simple. 



a. Sternum solid, truncated before and nicked behind, attached 

 to the thorax by a bony symphysis, covered with the end of 

 the pectoral and abdominal shields ; sternal plates 12 ; axil- 

 lary and inguinal plates moderate or none. 



* Pectoral plates small, short, triangular, lateral, far apart. 



1 . Manouria. 



** Pectoral plates broad, square, close together, side by side. 

 t Toes strong, free, not %cebbed, cross-shielded above. 



2. Geoemyda. Head covered with a thiu hard skin. Toes rather 



short, free ; claws 5 ' 4. 



tt Toes strong, webbed, cross-shielded above. 



3. Niooria. Head covered with a thin hard skin ; eyes large, 



close together, subsuperior. Toes very short, united. 



4. Geoclemys. Head covered with a thin hard skin, rhombic; 



forehead flat ; eyes lateral. Toes strong, shortly webbed. 



5. Emys. Head covered with a thin hard skin, broad, ovate; 



forehead convex ; eyes subsuperior ; branches of lower jaw 

 narrow, covered with the beak. Toes short, strongly webbed. 



6. Chrysemys. Head covered with a thin hard skin, oblong; 



forehead convex ; eyes subsuperior. Sternum broad, rounded 

 before and behind. Toes strongly webbed. 



ttt Tees elongate, largely vwbbed. with small scales above. 



7. Pseudemys. Head covered with a thin hard skin, ovate ; 



forehead convex ; eyes subsuperior ; branches of lower jaw 

 dilated, flat, covered with a soft skin. Toes short, webbed. 



8. Batagur. Head covered with a thin hard skin, broad, ovate ; 



forehead convex ; eyes subsuperior ; branches of lower jaw 

 narrow. Toes largely webbed. 



0. Malaclemys. Head depressed, covered with a soft skin, ovate ; 

 forehead convex; eyes subsuperior. Toes broadly webbed. 



b. Sternum divided by a central cross suture, attached to the 

 thorax by a ligamentous suture, covered by the end of the 

 pectoral and abdominal shields ; sternal plates 12; axillary 

 and inguinal plates very small. Toes webbed. 



t Legs scaly ; toes slightly webbed. 



10. Cistudo. Head rhombic; forehead flat; eyes lateral. Ster- 



num very broad; anterior lobe covered with the gular, 

 humeral and pectoral plates," and quite free. 



11. Lutremys. Head ovate; forehead convex; eyes subsui)erior. 



Sternum broad; tlie suture l)etween the two sternal lobes in 

 the short sterno-costal sutiu'e. 



tt Legs with crescentic shields ; toes broadly webbed. 



12. Cviora. Head rhombic ; forehead flat ; eyes lateral. Sternum 



very broad ; anterior lobe partly included in the sterno-costal 

 suture. 



13. Cyclemys, Head ovate ; forehead convex ; eyes subsujierior. 



Sternum rather narrower than the cavity at each end ; the 

 cross suture between the two sternal lobes in the middle of 

 the long sterno-costal suture. 



c. Sternum divided by two cross sutures; central lobe attached 

 to the thorax by a bony symphysis, covered by the end of the 

 abdominal shields only; sternal plates II or 8; the axillary 

 and inguinal plates large. Toes webbed. 



14. Kinosternon. Sternal plates 1 1 ; gular plates united ; humeral 



and pectoral distinct ; pectoral triangular. 



15. Aroinoclielys. Sternal plates 11 ; gular linear, rudimentary; 



pectoral broad, four-sided. 



16. Staurotypus. Sternal plates 8 ; gular, humeral and pectoral 



united together. 



B. Head and tail very large; sterno-costal symphysis covered 

 with one or three peculiar plates. 



a. Sternum cross-like, acute before; sternal plates 10, with a 



broad one on each side, over the sides of the sternum. 



17. Cbelydi-a. Head depressed, covered with a soft skin. Shell 



with a single series of mai'ginal shields. 



18. Macroclemys. Head large, high, covered with symmetrical 



horny plates. Shell with a double series of marginal shields 

 on each side. 



b. Sternum broad, truncated before ; sternal plates 12; sterno- 

 costal suture covered with three or four additional plates. 



19. Platysternon. Tail cylindrical, shielded. Shell depressed. 



20. Dermatemys. Tail ? Shell convex. 



These genera pass gradually one into the other, and the 

 similarity in the form of the sternum between Platyster- 

 non and Emys converts the series into a circle. The genus 

 Cistudo appears to unite them to the Land Tortoises, while 

 Chelydra has some affinities with certain of the Chelydce. 



A. Head and tail moderate ; sterno-costal suture simple. 



Emydina (part.), Gray, Ann. Phil. x. 210 (182.")). 

 Emydidse § A, Gray, Cat. Tort. B.M. 13 (1844). 

 Emys, Gray, Syn. Rejjf. 20. 



Dum. ^- Bib. Erp. Gen. ii. 234 ; Cat. Meth. R. 8. 



a. Sternum solid, truncated before and nicked behind, at- 

 tached to the thora.v by a bony symphysis ; sternal 

 plates 12; axillary and inguinal plates moderate or 

 none. Emydina. 



Emydidse § A. a, Gray, Cat. Tort. B.M. 13. 

 Emydina (part.), Gray, Ann. Phil. x. 210. 

 Clemmvs, IVagler, Syst. Repf. 137. 

 Fit.:. Syst. Repf. 29 (1843). 



* Pectoral plates small, short, triangular, lateral, far 

 apart. 



1. MANOURIA. 



Animal luiknown. Shell rather depressed ; caudal plates 

 double, separate. Sternum solid, broad, produced and 



