Page:Natural History, Reptiles.djvu/37

Rh that the feet are flattened into swimming-paddles, the toes being united, and enveloped in the same membrane: the anterior pair are greatly lengthened. Only the first two toes are furnished with claws, which are pointed; and one or other of these is apt to fall at a certain period of life. The pieces of which the plastron is composed do not form a continuous plate, but are variously dentelated, and leave wide

filled only by cartilage. The ribs are narrowed, and separated from each other at their external portion, but the entire circumference of the carapace is occupied by a circle of pieces corresponding to sternal ribs. The plates of the carapace are horny, and for the most part continuous at their edges, as in the majority of other Testudinata, but in some species, as that from which the beautiful Tortoise-shell is obtained, the posterior edge of each plate is produced, and overlaps the one that succeeds it.

The food of the Turtles consists chiefly of various kinds of sea-weeds, such as the Zostera