TESTTTDINID.E. 95 



the specimen figured by Leidy in the ' Smiths. Contrib. 

 Knowl.' vol. vi. art. 7, pi. xx. (as Testudo hemisjiJuerica), 

 that there can be little doubt as to the generic identity of 

 the two forms. This is especially shown in the uninter- 

 rupted contour of the anterior border of the epiplastrals, 

 and the contour of the entoplastral. The thickening of 

 the epiplastrals characteristic of the land-tortoises is well 

 shown. Croizet Collection. Purchased, 1848. 



40771. A nuchal bone, probably referable to the same form as the 

 preceding ; from Sansan. There is a distinct nuchal 

 shield, and the absence of emargination of the anterior 

 border is well shown. The thickening of the under 

 surface shows that the specimen belongs to a land- 

 tortoise. Presented by C. Falconer, Esq., 1867. 



Genus PTYCHOGASTER, Pomel 1 . 



Neural bones short, and comprising an alternation of smaller 

 tetragonal and larger octagonal ones 2 ; costals alternately long and 

 short at their inner and outer extremities ; nuchal emarginate. 

 Hyoplastrals united to the carapace by suture, with the axillary 

 buttress extending halfway across the 1st costal ; hypoplastrals 

 joining the carapace by a straight ligamentous union, and movable 

 upon a transverse hinge : entoplastral cut by humero-pectoral 

 sulcus (fig. 18), epiplastrals somewhat thickened ; xiphiplastrals 

 without distinct notch. Vertebral shields hexagonal and of 

 moderate width ; pectorals short antero-posteriorly. 



Ptychogaster emydoides, Pomel 3 . 



The type species. Shell moderately vaulted, long, and narrow ; 

 the neurals smooth in the adult, but more or less distinctly carinated 

 in the young. Thickened rim of epiplastrals without distinct median 

 prominence. Length about 0,280 (11 inches). 



It may be observed that in this and the following forms the bones 

 of the shell anchylose more or less completely together in the 

 adult. 



Sab. Europe (France). 



1 Bull. Soc. G-eol. France, ser. 2, vol. iv. p. 383 (1817). 



2 See Grervais, Zool. et Pal. Franchises , 2nd ed. pi. liii. fig. 5. 



3 Oc. cit. p. 385. 



