Here are a variety of natatory — that’s swimming related — audiobooks, to dive into this summer.

In those Copepods in which the palps of the mandibles as well as the antennae are biramous and natatory, the first three pairs of appendages retain throughout life, with little modification, the shape and function which they have in the nauplius stage, and must, in all likelihood, be regarded as approximating to those of the primitive Crustacea.

The eyes were probably stalked, the antennae and mandibles biramous and natatory, and both armed with masticatory processes.

They may, however, be natatory as in many Ostracoda and Copepoda, or prehensile, as in some Copepoda.

The thoracic limbs have the endopodites converted, as a rule, into more or less efficient walking-legs, and the exopodites are often lost, while the abdominal limbs more generally preserve the biramous form and are, in the more primitive types, natatory.