CRYPTODIRA. 11 
Suborder I. THECOPHORA. 
Thecophora, Dollo, Bull. Mus. Belg. iv. 1886, p. 91. 
Dorsal vertebree and ribs immovably united and expanded into 
bony plates forming a carapace. Parietals prolonged downwards, 
forming a suture with the pterygoids or separated from the latter 
by the interposition of the epipterygoid. 
Superfam. A. CRYPTODIRA. 
Chelonii, part., Amyd, part., Oppel, Ordn. Rept. 1811; Agassiz, 
Contr. N. H. U. 8.1. 1857. 
Testudinea, Hmydea streptopelyca, Euereta, part., Stannius, Zoot. 
Amph. 1854. 
Tylopoda, Steganopodes, Oiacopodes, part., Gray, Suppl. Cat. Sh. 
Rept. 1. 1870. 
Cryptodira, part., Cope, Proc. Amer. Assoc. Adv. Se. xix. 1870, 
De Zon. 
Peltochelyide, part., Seeley, Q. Journ, Geol. Soc. xxxvi. 1880, p. 412. 
Dactylosterna, part., Clidosterna, Lysosterna, Cope, Proc. Amer. Philos. 
Soc. xx. 1882, p. 143. 
Dactyloplastra, part., Clidoplastra, Lysoplastra, Dollo, Bull. Mus. 
Belg. iv. 1886, p. 91. 
Paradiacostoidea, part., Baur, Zool. Anz. 1887, p. 99. 
Neck bending by a sigmoid curve in a vertical plane; cervical 
vertebrae without or with mere indications of transverse processes ; 
centrum of the last cervical articulating with the centrum of the 
first dorsal, Mandible with articulary concavities ; outer border 
of tympanic cavity incompletely bony ; pterygoids narrow in the 
middle, in contact on the median line. Pelvis not anchylosed to 
the carapace and plastron. Digits with not more than three 
phalanges. piplastra in contact with hyoplastra; entoplastron, if 
present, oval, rhomboidal, or T-shaped. A complete series of 
marginal bones, connected with the ribs. 
The following is a brief sketch of the Osteology of the Group. 
Dorsat Vertesrat Corumn anp Carapace.—There are ten dorsal 
vertebree, the first and last of which have no share in the formation of 
the dorsal shield. The first has a short depressed centrum, concave 
anteriorly, with strong prezygapophyses articulating with the post- 
zygapophyses of the last cervical; it bears a short rib anteriorly, 
which is connected with the second rib, and, in a few genera 
(Kachuga, Batagur, Callagur, Hardella), also with the ascending 
