The resemblance of these creatures to miniature Macrura is alluded to in the generic name Nannastacus, meaning dwarf-lobster.
SHRIMP, a name applied in general to the smaller crustacea of the order Macrura and in particular to an edible species found on the coasts of northern Europe (Crangon vulgaris).
Between the Brachyura and Macrura some authors uphold an order Anomura, though in a much restricted sense, the labours of Huxley, Boas, Alcock and conjointly Alphonse Milne-Edwards and Bouvier, having resulted in restoring the Dromiidea and Raninidae to the Brachyura, among which de Haan long ago placed them.
The name of shrimps is sometimes given to members of the order Schizopoda, which differ from most of the Macrura in having swimming branches or exopodites on the thoracic legs.
Where the sac is completely closed it generally contains no solid particles, but in a few Macrura a single otolith secreted by the walls of the sac is present.
The French authors argue that from the macruran lobsters (Nephropsidae) anciently diverged two lines: one leading through the Dromiidea to the genuine Brachyura; or crabs, the other independently to the Anomura proper, which may conveniently be named and classed as Macrura anomala.
We need only mention the Mysis-stage (better termed Schizopodstage) found in many Macrura (as, for example, the lobster), which differs from the adult in having large natatory exopodites on the thoracic legs.