The fore limbs, to use Professor Fraas’s words, “are among the most interesting of all the peculiarities of _Geosaurus_,” and show very clearly that these animals were excellent swimmers. The humerus is remarkably short and broad; the two bones of the forearm, the radius and ulna, are broad, rounded, or angular plates, not long bones, as in other crocodiles; the wrist bones also are broad and plate-like. The three bones of the thumb, that is of the digit which received most strongly the impact of the water in swimming, are also broad and flat. All of these bones are marvelously aquatic in type, as will be evident from a comparison of them with the corresponding bones of the ichthyosaurs and mosasaurs. The bones of the other fingers, however, were not much changed from the ordinary crocodilian form, as a further comparison of them with the fingers of a land crocodile will show. Furthermore the whole limb or paddle was very small in comparison with the hind leg, and it was attached very near to the head. The relative proportions of the front and hind limbs in the geosaurs, gavials, and alligators are instructive as showing the progressive decrease in size of the front legs from the subaquatic, through the semiaquatic, to the almost purely aquatic type. The hind legs, strangely enough, were not very different in size and structure from those of the gavials or teleosaurs. The thigh bone is long and slender, though the bones of the leg and ankle are somewhat shortened and flattened, as are also those of the first toe. There were no claws on the hind feet, a distinctly aquatic adaptation, and the toes were certainly webbed. The pelvis, while not especially stout, is of good size, and was firmly attached to the sacrum. Perhaps all these characters may best be summed up in the words of Professor Fraas, as translated: