vertebrata above the fishes and amphibia (= frogs, toads, newts,
and etc.)--
(a) Absence of gills (not gill slits, note) at any stage in
development.
(b) An amnion, and
(c) An allantois in development.
The meaning of (b) and (c) we shall explain to the student in the
chapters on embryology. We simply mention them here to render
our table complete.