Macrura sentence example
- The shrimps and their allies are distinguished from the larger Macrura, such as the lobsters and crayfishes, by greater development of the paddle-like limbs of the abdomen or tail, which are used in swimming.
- 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.
- There are at least seven orders: the stalk-eyed Brachyura, Macrura, Schizopoda, Stomatopoda, and the sessile-eyed Sympoda, Isopoda, Amphipoda.
- 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 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.Advertisement
- Spence Bate maintained that the Schizopoda ought not to form a separate order, but to be ranged as a macruran tribe, "more nearly allied to the degraded forms of the Penaeidea than to those of any other group" ("Challenger" Reports, " Macrura," p. 472, 1888).
- - The Macrura anomala, or Anomura in restricted sense, are popularly known through the hermit-crabs alone.
- The resemblance of these creatures to miniature Macrura is alluded to in the generic name Nannastacus, meaning dwarf-lobster.
- The sac is open to the exterior in most of the Macrura, but completely closed in the Brachyura.
- 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.Advertisement
- 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.
- The earliest forms, from the Lower Oolite and later, belonging chiefly to the extinct family Prosoponidae, have been shown to have close relations with the most generalized of existing Brachyura, the deep-sea Homolodromiidae, and to link the Brachyura to the Homarine (lobster-like) Macrura.
- Orders: Decapoda (Sub-orders: Brachyura, Macrura), Schizopoda (including Anaspides), Stomatopoda, Sympoda (Cumacea), Isopoda (including Tanaidacea), Amphipoda.