T. aulcata will serve for an illustration of this genus : it is the species assigned to Africa and America with a 1. M. de Orbigny is stated to have himself collected the young of Testudo aulcata in Patagonia, where, according to him, the species is very common. Messrs. Durneril and Bibron declare that other specimens come without doubt from Africa.
Hognoptu, Dum. and Ilibr.—Four toes only on each foot., and all unguiculate ; carapace and sternum of a single piece. There are two species : ll. ortolan, ; 11. slogan,.
Py.ris, MI.—Feet each with five toes, the posterior ones with four nails only; carapace of a single piece ; sternum moveable anteriorly.
This genus in the only Land Box-Tortoise ; but an analogue (Sterwotheriss) occurs among the Marsh-Tortoises, in the division of Pleurodere Elodians.
The anterior portion of the pleatron of Py.ris, which is susceptible of motion, is of very small extent, for it only reaches, backwards, to the space of the first two pairs of sternal plates, and conse qucutly it is under the strongly indi cated suture of the second with the third pair that the elastic ligament which per forms the office of A hinge is seen. By means of this sort of moveable door or lid, the Pyxis can, by lowering it at will, protrude its head and its fore feet, and by raising it, shut itself up in a sort of box, for the edges of this hinged operculum closely fit those of the cara pace, which serve it as a door-case. The animal then has nothing to fear, be cause its sternum protects behind, by its enlargement, the space by which the feet and the tail can be put forth and deeply drawn up. P. arachnoides is the only species known.
Einiryn, Bell.— Feet with five toes, the posterior ones with four nails only; carapace moveable behind ; sternum of a single piece.
Messrs. Dum4ril and Bibron observe that this is the most curious of the family Chersites. The Cho Ionians that compose it alone enjoy the faculty of moving the posterior part of their carapace in order to lower it and apply it against the plastron, so as com pletely to close the osseous box behind, as the Pyzides close theirs before when they elevate the moveable anterior portion of their plastron. But, as we have seen, the mobility of the anterior part of the sternum is In Py.ris due
to the presence of an elaatio ligament which performs the office of a hinge, whilst In Kini.rys the carapace offers no really moveable articulation ; the hones, the vertebra:, And ribs are the parts which bend. In consequence of thin elasticity of the bonen and their thinness, the carapace can be moved down to approximate the sternum. The sinuous lino on which this flexion operates in indi cated externally by n slight space, which in filled by a sort of fibro cartilaginous tissue. Thin undulated line exists between the ante penultimate and the pent:Minato margined:acrid plate.
The three known species have not, like all the other Chersinns, the abdominal plates much more extensive than the other horny plates of the sternum, which, joined to the enlargement and the rounded contour of the plastron behind, approximates them in a certain degree to Ciatialo, the first genus of the Flothans. There are three species llongeana ; K. erns; K. Belliona.
l'aunanian notices a Land-Tortoise in the woods of Arcadia, whose shell was used to make lyres.
Family TI. F.lodiana—Marah-Tortoises.
The habits of the Elodisna differ very much from those of the other three great groups of Cheloniann. The Marsh-Tortoises have not the slowness of the band-Tortoines. They swim with facility, and on land make much quicker progress than the Chersians. They frequent small streams whose course is not too rapid, lakes, ponds, and marshes : they are not almost entirely vegetable-feeders, like the Chersians and Thalassians, but, like the Potamians, prey on living animals ; river mollusks, inourous and Urodele Batrachians, and Aunelides are their food.
The eggs are generally spherical, with a calcareous shell, And white, like those of the other Cheloninns. The females deposit them in shallow cavities, which they hollow out in the earth, nearly in the same manner as the Land-Tortoises; but the Elodians prefer the banks of the waters where they dwell, in order that their young ones may the more easily there find refuge from their numerous enemies. The number of eggs varies according to the species, and probably according to the age of the individuals, for the females are capable of producing fertile eggs for some years before they have attained their full growth.