8. MVLACOCLKVMTfl. 89 



Synopsis of the Species. 



Carapace rniich depressed ; the length of 

 the hind lobe of the plastron much ex- 

 ceeds the width of the bridge 1. terrapen, p. 89. 



Carapace tectiform, the vertebral keel obtuse 

 and not tubercular ; hind margin but 

 moderately serrated 2. r/eograj^Jiica, p. 90. 



Carapace tectiform, with strong vertebral 

 keel ending in a tubercle on each shield ; 

 posterior margin very strongly serrated . 3. lesueurii, p. 91 . 



1. Malacoclemmys terrapen. 



Testudo terrapin, Schoppf, Test. p. G4, pi. xv. (1792). 



centratii., DmaJ. Rcpf. ii. p. 153 (1802). 



coucentrica, tShniv, Zoo/, in. p. 43, ])1. ix. (1802). 



Emvs centrata, Schwelr/q. Proclr. p. 32 (1814); Say., Journ. Ac. 



Phikal. iv. p. 205 (1S2.3). 

 Testudo palustris [non Gt)iel.), Lecotitc, Ann. Lye. K. Y. iii. p. 113 



(1830). 

 Terrapene palustris, Bonap. Ossorv. s. sec. Ed. d. H. A. p. 157 (1830). 

 Emys concontrica. Gray, Sipi. Rept. p. 27 (1831) ; Bell, Mon. Test. 



pi. — (1834) ; Bum'. ^- Bibr. ii. p. 201 (1835). 

 terrapin, Ilulhr. N. Am. Ilcrp. i. p. 87, pi. xii. (1842) ; Bekny, 



Faun. N. ¥., Bept. p. 11, pi. xxiii. fig. 63 (1842) ; Wied, N. Acta 



Ac. Leop.-CaroJ. xxxii. i. p. 1(5 (1805). 



palustris, Dehiy, I. c. p. 10, pi. iii. fig. 5. 



Malaciemys conceutrica, Gray, Cat. Tort. p. 28(1844), and Sh. Rept. 



1. p. 37 (vars. concentrica, centrata, tuberculifera) (1855), and 



Suppl. p. 42 (1870). 

 Emys macrocephala, Gray., Cat. Tort. p. 20. 

 JMalacoelemmvs palustris, Ayassiz, Contr. N. H. U. S. i. p. 437, pi. i. 



figs. 10-12 '(1857). 

 Clemmvs terrapin, Strauch, Chelon. Stud. p. 132 (18G2), and Verth. 



Schiidkr. p. 90 (1865). 

 Emys pileata, Wied, I. c. p. 17, pi. i. figs. 2 & 3, & pi. ii. figs. 1-4. 



Carapace much depressed, oval, posterior border sometimes dis- 

 tinctly reverted, very rarely serrated ; a more or less strong, inter- 

 rupted, vertebral keel or series of subconical tubercles ; dorsal 

 shields concentrically grooved, or smooth ; nuchal moderate, as 

 broad as long or a little broader than long ; first vertebral broader 

 anteriorly tban posteriorly ; vertebrals 2 to 4 much broader than 

 long, broader than costals. Plastron a little smaller than the 

 opening of the shell, obtusely angulated laterally ; bridge rather 

 narrow, its width considerably less than the length of the bind 

 plastral lobe ; latter openly notched posteriorly ; relative proportions 

 of the plastral shields very variable ; the suture between the abdo- 

 minals and that between the anals are of equal length, or the latter 

 is the shorter ; pectorals usually much smaller than abdominals, 

 sometimes very slightly smaller; axillary and inguinal rather small. 

 Head large ; snout short, more or less obtusely pointed ; upper beak 



