fish

All fishes, with the exception of the flat selachians, lie down
side by side, and copulate belly to belly. Fishes, however, that are
flat and furnished with tails-as the ray, the trygon, and the
like-copulate not only in this way, but also, where the tail from
its thinness is no impediment, by mounting of the male upon the
female, belly to back. But the rhina or angel-fish, and other like
fishes where the tail is large, copulate only by rubbing against one
another sideways, belly to belly. Some men assure us that they have
seen some of the selachia copulating hindways, dog and bitch. In the
cartilaginous species the female is larger than the male; and the same
is the case with other fishes for the most part. And among
cartilaginous fishes are included, besides those already named, the
bos, the lamia, the aetos, the narce or torpedo, the fishing-frog, and
all the galeodes or sharks and dogfish. Cartilaginous fishes, then, of
all kinds, have in many instances been observed copulating in the
way above mentioned; for, by the way, in viviparous animals the
process of copulation is of longer duration than in the ovipara.