2.  “Let the waters bring forth moving creatures after their kind.”  God caused to be born the firstlings of each species to serve as seeds for nature.  Their multitudinous numbers are kept up in subsequent succession, when it is necessary for them to grow and multiply.  Of another kind is the species of testacea, as muscles, scallops, sea snails, conches, and the infinite variety of oysters.  Another kind is that of the crustacea, as crabs and lobsters; another of fish without shells, with soft and tender flesh, like polypi and cuttle fish.  And amidst these last what an innumerable variety!  There are weevers, lampreys and eels, produced in the mud of rivers and ponds, which more resemble venomous reptiles than fish in their nature.  Of another kind is the species of the ovipara; of another, that of the vivipara.  Among the latter are sword-fish, cod, in one word, all cartilaginous fish, and even the greater part of the cetacea, as dolphins, seals, which, it is said, if they see their little ones, still quite young, frightened, take them back into their belly to protect them. Narrated by Ælian (Anim i. 16) of the “glaucus,” a fish apparently unknown.