Century Dictionary and Cyclopedia - In zoology: Latreille's name
for all crustaceans, except the stalk-eyed and sessile-eyed
groups. It is restricted to a portion of the lower crustaceans,
but the classifications vary so much that the term is gradually
being abandoned. The groups usually noted by it are the
Ostracoda, as Cypris; Copepoda, as Cyclops; Cladocera, as
Daphnia (see Daphnia); Branchiopoda, as the brine-shrimp
(Artemia salina) and the glacier-flea (Podura nivalis);
Trilobites, all of which are extinct; Merostomata, of which
Eurypterus and Pterygotus are the best-known examples among
fossils, the king-crab being the only living example. To these
some add the Epizoa, or parasitic crustaceans. No zoological
definition can be framed to include all these groups, each of
which is now usually regarded as a distinct order. The
Entomostraca appear to have been first named by O. F. Müller in
1785, and have also been called Gnathopoda, as by H. Woodward. -
In various Systems, one of two main divisions of Crust