CRYPTOniBA. 1 1 



Suborder 11. TIIECOPIIORA. 



Thccophora, Dollo, linll. Miia. Ikhj. iv. 1880, p. Ul. 



Dorsal vcrtcbnc 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., Amydte, part., Oppel, Onhi. liept. 1811 ; Afjassiz, 



Contr. N. H. U. S. i. 1857. 

 Testudiuea, Emydoa streptopelyca, Eueveta, part., Sfamihi.s, Zoof. 



Amph. 1854. ' 

 Tylopoda, Steganopodes, Oiacopodes, part., Gray, Suppl. Cat. Sh. 



liipt. i. 1870. 

 Crvptodira, part., Cope, Pi-oc, Amer. Axsoc. Adv. Sc. xix. 1870, 



p. -l-V). 

 PeltochelyidiB, part., Seelvj/, Q. Jouni. OcoL Svc. xxxvi. 1880, p. A\-2. 

 Dactylosterna, part., Clidosterna, Lysosterna, Cope, Proc. Amer. I'/ii/o<. 



Sue. XX. 1882, p. 148. 

 Dactvloplastra, part., Clidoplastra, Lvsoplastra. Dollo, Bull, 3Iu.s. 



Belfj. iv. 1886, p. 91. 

 Paradiacostoidea, part., Baur, Zoul. Anz, 1887, p. 99. 



Neck bending by a sigmoid curve in a vertical plane ; cervical 

 vertebra? 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 ; ])terygoids narrow in the 

 middle, in contact on the median line. Pelvis not anchyloscd to 

 the carapace and plastron. Digits with not more than three 

 phalanges. Epiplastra in contact with hyoplastra ; cntoplastron, 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. 



Dorsal Yerteukal Coliimx a>^d Carapace. — There are ten dorsal 

 vertebrae, the first and last of uhich have no share in the formation of 

 the dorsal shield. The first has a short depressed centrum, concave 

 anteriorly, with strong pra?zygapophyses 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 

 {Kaclmga, Batajur, Callacfur, RardeJla), also with the ascending 



