In no other way could the bones have been used equally. The avian ilium would suggest a probability that they also at times stood erect like birds, from which position they could with more ease expand their wings; nor is such an idea opposed by the resemblance of some bones of the hind-limb to what obtains in birds, and of the neck of the femur to what is seen in mammals of great power in the hind-legs. That they lived exclusively upon land and in air is improbable, considering the circumstances under which their remains are found. It is likely that they haunted the sea-shores, and, while sometimes rowing themselves over the water with their powerful wings, used the wing-membrane as does the Bat to enclose their prey and bring it to the mouth. But the superior development of the pneumatic foramina suggest that their activity was greater than in ordinary sea-birds. The large Cambridge Pterodactyles probably pursued a more substantial prey than dragon-flies. Their teeth are well suited for fish, but probably fowl and small mammal, and even fruits, made a variety in their food. As the lord of the cliff, it may be presumed to have taken toll of all animals that could be conquered with tooth and nail. From its brain it might be regarded as an intelligent animal. The jaws present indications of having been sheathed with a horny covering, and some of the species show a rugose anterior termination of the snout suggestive of fleshy lips like those of the Bat, and which may have been similarly used to stretch and clean the wing-membrane. The high temperature, coupled with the sub-aerial life, are opposed to the idea of the animal having been naked. The undisturbed condition of the skeleton and some points of structure are opposed to the idea of their having had large feathers. The absence of such remains does not favour the hypothesis of their having been covered with scales, though in the legs of birds a scaly covering is met with. I should anticipate for them a filamentous downy feather, or hair, like a Bat's. The Bat combs its hair with its claws, and the Ornithosaurians may have used their claws in a similar way. They cannot be supposed to have been gregarious, from the large number of species relatively to specimens. The reproduction may have been much the same as in birds; and the young were probably reared with affectionate care[X]. [Footnote X: Mr Carruthers has shown me crushed Turtle-like eggs from the Stonesfield slate, which in the external pitting of the egg-shell are not so different from some birds as to preclude a suspicion that they might possibly be Ornithosaurian.] * * * * * _The following notes indicate structures in perfect specimens from the Lithographic slate which supplement the fragmentary remains from the Cambridge Greensand_[Y]. [Footnote Y: The German animals form different family groups. And it cannot be inferred that the structures seen in them pertained to Cambridge specimens.]