Aristotle [ca. 350 BCE] (De animalibus): [Aristotle clearly says the selache is a genus of fish, not an particular species of fish.] [Book 1, chapter 4.2] Some viviparous animals are internally oviparous, as the selache... In different animals the foetus assumes a different form, when first brought into the world, and is either a living creature, an egg, or a worm. The eggs of some animals, as birds, are hard-shelled, and are of two colors. Those of the selache and some other animals are soft-skinned, and have only one color. [Book 4, chapter 10.5] The selache sleep so soundly that they may be taken with the hand...[Book 6, chapter 10.1 ] The selache are viviparous, having first of all produced ova internally; and these they bring up in themselves... [Book 6, chapter 10.9] The selache descend from the ocean and deep water to the shore, to produce their young, both for the sake of the warmth, and care of their offspring. - [Cresswell translation, 1887]

Thomas of Cantimpré [circa 1200-1272 CE] (Liber de natura rerum, Marine monsters 6.11): The celethi is a marine animal, as Aristotle says, which surpasses other monsters of the sea or land in generating eggs in its womb; which, in due time, having come out of the womb, worms come out of them. When it has conceived, the fetus receives a perfect form, and the animal becomes like its parents with incredible speed after birth. This animal sleeps heavily, so that it can be caught by hand. This animal has a large heart compared to its body, and yet it is very timid. - [Badke translation/paraphrase]

Albertus Magnus [1st century CE] (De animalibus, Book 24, chapter 1.27): Celeti, as we have said before, is a genus of animals containing many species under it. But first it lays eggs, and afterwards gives birth, and then it is formed into the species of the one giving birth. But it is an animal that sleeps heavily on account of the weight of its head, so that it can be caught in the hand while it sleeps. - [Catholic Library]