Of the other animals supplied with blood, some differ but
little, as is the case with birds; others have systems analogous, as
fishes; for viviparous fishes, such as the cartilaginous species,
are gristle-spined, while the ovipara have a spine which corresponds
to the backbone in quadrupeds. This exceptional property has been
observed in fishes, that in some of them there are found delicate
spines scattered here and there throughout the fleshy parts. The
serpent is similarly constructed to the fish; in other words, his
backbone is spinous.