Before ending these preliminary remarks, there might be mentioned the marine monsters, such as mermaids, sea-serpents, and the like, which from time to time have been reported; even at the present day there are people who devoutly believe that they have seen horrible and impossible demons in the sea. Pare describes and pictures a monster, at Rome, on November 3, 1520, with the upper portion of a child apparently about five or six years old, and the lower part and ears of a fish-like animal. He also pictures a sea-devil in the same chapter, together with other gruesome examples of the power of imagination. Early Teratology.--Besides such cases as the foregoing, we find the medieval writers report likely instances of terata, as, for instance, Rhodiginus, who speaks of a monster in Italy with two heads and two bodies; Lycosthenes saw a double monster, both components of which slept at the same time; he also says this creature took its food and drink simultaneously in its two mouths. Even Saint Augustine says that he knew of a child born in the Orient who, from the belly up, was in all parts double. The first evidences of a step toward classification and definite reasoning in regard to the causation of monstrosities were evinced by Ambroise Pare in the sixteenth century, and though his ideas are crude and some of his phenomena impossible, yet many of his facts and arguments are worthy of consideration. Pare attributed the cause of anomalies of excess to an excessive quantity of semen, and anomalies of default to deficiency of the same fluid. He has collected many instances of double terata from reliable sources, but has interspersed his collection with accounts of some hideous and impossible creatures, such as are illustrated in the accompanying figure, which shows a creature that was born shortly after a battle of Louis XII, in 1512; it had the wings, crest, and lower extremity of a bird and a human head and trunk; besides, it was an hermaphrodite, and had an extra eye in the knee. Another illustration represents a monstrous head found in an egg, said to have been sent for examination to King Charles at Metz in 1569. It represented the face and visage of a man, with small living serpents taking the place of beard and hair. So credulous were people at this time that even a man so well informed as Pare believed in the possibility of these last two, or at least represented them as facts. At this time were also reported double hermaphroditic terata, seemingly without latter-day analogues. Rhodiginus speaks of a two-headed monster born in Ferrari, Italy, in 1540, well formed, and with two sets of genitals, one male and the other female. Pare gives a picture of twins, born near Heidelberg in 1486, which had double bodies joined back to back; one of the twins had the aspect of a female and the other of a male, though both had two sets of genitals.