rudiment of a thumb, and at the outer edge of the ankle of the hind foot there is for the most part a tubercle, which in some genera is expanded into a large oval disk with free edges; this tubercle is analogous to one of the little bones of the human ankle, and is not, as has been supposed, the rudiment of a sixth toe.
The motions of the Frogs are lively, and the muscular power displayed by them very great, particularly in swimming and leaping. “The muscles of the abdomen,” as Mr. Broderip observes, “are more developed than in the other reptiles, offering, in this particular, some analogy to the abdominal structure of the Mammifers. But it is in the disposition of the muscles of the thigh and legs, in the Frogs and other Anourous Batrachians, that the greatest singularity is manifested. These, whether taken conjointly or singly, present the greatest analogy with the muscular arrangement of the same parts in man. We find the rounded, elongated, conical thigh, the knee extending itself in the same direction with the thigh-bone, and a well-fashioned calf to the leg. It is impossible to watch the horizontal motions of a frog in the water, as it is impelled by these muscles and its webbed feet, without being struck by the complete resemblance in this portion of its frame to human conformation, and the almost perfect identity of the movements of its lower extremities with those of a man making the same efforts in the same situation. By the aid of these well-developed lower limbs, and the prodigious power of their muscular and bony levers, a Frog can raise itself in the air to twenty times its own height, and traverse, at a
