History of Monsters 429

...we might observe them in families. Truly, because we cannot peer into the secret depths of these things, the result is that a smaller number of these monsters is shown.

XII. Nevertheless, we present here for your inspection an image of a two-headed fish, which was caught in the Nile, the river of Egypt, not far from the town called Latislana. This fish nearly equaled the size of a crocodile and was of a grayish color marked with whitish spots. It possessed two heads, as shown in the illustration, and for that reason could be called *Dicephalos*, or two-headed. However, because it seemed to consist of two fish bodies joined to a single tail, this fish should perhaps be classified among two-bodied monsters rather than among the two-headed ones.

If we investigate the specific causes of two-headed monsters before proceeding further, we should note that these primarily arise from an abundance of seminal matter. For if this matter—destined for the formation of a particular member, such as the head—is divided into two parts by the power of the formative faculty, two heads will result in a single subject. If the supply of matter intended for only one head is small, it will produce very small heads; but if it was intended for two, then two heads proportionate in size to the body will result.

This spermatic matter is that which remains from the surplus nourishment used for the parents' heads; because it is abundant, the formative faculty sometimes divides it into two parts, and two-headed offspring are procreated. Paradoxically, a deficiency of this same matter can also cause a two-headed monster. This tends to happen when the matter contained in the womb is insufficient to generate twins but is too abundant for a single fetus. In such cases, Nature, first applying itself to the procreation of the head, doubles it due to the surplus of matter, but then, as the matter runs out, forms only a single body for the rest. This explains why many monsters of this type have been observed.

Others attribute this kind of monster to superfetation—when new seminal matter entering the womb joins with the previous matter, allowing some part of the fetus to be doubled wherever this new matter is deposited. However, I believe this happens very rarely. A part generated from this subsequent matter and doubled alongside the first could never reach full perfection. Similarly, we cannot be led to believe that this depends on the discharge of maternal seed without superfetation; for the power of the paternal seed, already occupied in the procreation of the first fetus, would be pulled away from its initial work if it were to act upon the newly arrived seed.

To these causes, we must add the narrowness of the womb, which certainly seems worthy of consideration in this case, especially when a two-headed fetus is born in a first delivery. Indeed, an abundance of matter in a narrow space might form the principal parts—namely the heads—intended for twins, but cannot be converted into the remaining doubled parts because the tight space will not accommodate them. Consequently, from the duplicates, only one body is formed, and a two-headed monster is generated. It is true, however, that the lower parts of such a monster are usually thicker than normal.

Others trace the cause of a monster with redundant parts back to monstrous parents. If both parents happen to be afflicted with some monstrous defect, then monstrous offspring can easily be generated, because Nature is very diligent in perpetuating species. However, it does not necessarily follow that if the parents are two-headed, a two-headed child will always proceed from them. Their heads contribute such a small portion of matter to the seed that it can only serve the formation of one head, not a doubled one. Nor can an abundance of food provide a cause for two-headedness; for once a fetus is conceived in the womb, it can grow for the duration of its development, but it cannot double its parts. This is often observed in girls whose heads have grown to an enormous size because nourishment was pulled to the head by a great attractive force or was constantly supplied from other lower parts.

Nor should the cause of two-headedness be attributed to the mental affections of the parents, as some have claimed. This is because the parents' thoughts and imaginations reside only in the substance of the spirits; therefore, they could by no means produce a monster remarkable for its superfluity of parts. It remains, then, that the causes