Difficulty of entitling a subclass corresponding to every combination.
This superorder is equivalent to the subclass Azygostei of Hay.
This subclass, like the previous one, contains only a single order, viz.
This subclass contains some of the most remarkable of the seaweeds.
There remains the fourth subclass—Dipnoi or Dipneusti, the lungfishes.
Embryo with a pair of opposite cotyledons, or in Subclass II.
The fourth subclass, Cirripedia, comprises the Barnacles and Acorn-shells.
This limitation of parts places them in a higher rank than the corals of the first subclass.
The subclass Copepoda comprises animals, for the most part of microscopic size, which are abundant in fresh water and in the sea.
The subclass c forms an exogamous unit with e, and the subclass d with f.