Discoidal plates to the number of thirteen, not imbricated. Muzzle short, rounded. Upper jaw with a slight notch in front and small dentilations on the sides; horny case of the lower jaw formed of three pieces and having its sides deeply dentilated. A nail on the first toe of each foot, C. Mydae. Messrs. Dumtril and Bibron observe that this and the three following species are so similar, that it is possible for them to form one species only : but they add that this question can only be satisfactorily solved by those who have opportunities of comparing the living animals.
C. 'virgule; C. maculosa ; C. marmorata.
Sub-Genus 2.—Imbricated dheloues.
Plates of the disc imbricated and thirteen in number. Muzzle long and compressed. Jaws with straight edges without dentilations, curved slightly towards each other at their extremities. Two nails on each fin.
This turtle has been taken on many of the European coasts ; several of large size (700 lbs. and 800 lbs. in weight) have been captured on those of Britain. One case, where the capture was effected off the coast of Scarborough, should be a warning not to use it rashly as food. Pennant relates that one of the three taken in 1748 or 1749 was parchased by a family, who invited several persons to partake of it. A gentleman present told the guests that the flesh was unwhole some, but one of the company persisted in eating of it, and suffered most severely, being seized with dreadful vomiting and purging ; and yet the Carthusians, Pennant tells us, are said to eat no other species. It would seem, then, that the severe effect above noticed must have been accidental, and the animal may have been in an unhealthy con dition. It is said to grow very fat; but the flesh is reported to be coarse and bad. The French name is given probably upon the supposition that it was the species used by the ancients in the early construction of the lyre.
This and the last-named turtle are the only species of the Chelonia that have been taken alive on the British coasts. Professor Bell in his ' British expresses his conviction that several of the "fresh-water species, both of Europe and North America, might be naturalised in the southern parts of England. The Terrapene Europera," he says, " the common Laenstrine Tortoise of the continent, he found in Portugal, Spain, Italy, and Greece, in France, and even in Prussia.
These tortoises are eaten by the inhabitants of all the countries in which they are found ; and as they live principally upon small fish, the air-bags of whieh they reject; it is said that the people are wont to judge of the quality of the tortoises to be found in a lake or pond by the number of air-hags which are seen swimming on the surface of the water. T once placed In a small pond, in which were some of these Fresh-Water Tortoises, six small living fish, and on the following morning I found the air-bags of five of them floating on the surface of the water and the sixth fish still alive. In some parts they are fed upon grains and other nourishing food, and fattened for the table. There are also several American species of blip, or Fresh-Water Tortoise, which will bear a greater degree of cold than that of most of our winters without perishing; and it is certainly desirable that a wholesome and agreeable food, like that afforded by some of these, should not be lost to us, if the species can be easily perpetuated and multiplied in our climate." Several species of Fresh-Water Tortoises are now in the collection of the Zoological Society, in the Aquavivarium of the Regent's Park Gardens.
The following list of Chdonia, arranged according to their geogra phical distribution, is from Dr. J. E. Gray's, 'Catalogue of the Tortoises and Crocodiles, Sc., In the Collection of the British :Museum.' When a species is found in two of the larger divisions of the list on account of its extensive range, it is preceded by an asterisk.
Fossil Cuvier, in his treatise upon Fossil Tortoises, observes that the number of living species is so considerable that it is very difficult to decide whether a fossil tortoise is or is not of an unknown species; inasmuch as it is not only necessary, before arriving at this conclusion, to compare the carapaces and plastrons covered with their horny plates or scales, as they are ordinarily seen in cabinets and repre sented in books, but also the skeletons, so the observer may accurately study the joining of the ribs and other bones which concur to compose their cuirasses. Ho names twenty-nine species that he himself bad stripped of their covering, and says that he had perfonned that operation on °there beside.