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(invertebrate zoology)
A subclass of Crustacea erected to include the primitive crustacean Hutchinsoniella macracantha.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



a subclass of small primitive crustaceans. The body is elongate, measuring as much as 3 mm in length. It consists of a head, a ten-segmented thorax with legs, and a nine-segmented legless abdomen. At the end of the body is a ramus with two long bristles. The legs are used for locomotion and respiration, as well as for directing food toward the mouth opening. There are two pairs of antennae on the head, small upper jaws, and two pairs of lower jaws, which are practically indistinguishable from the thoracic limbs. The animals lack eyes, a condition related to their burrowing way of life. The female lays eggs into an egg sac located on the last segment of the thorax. Nauplii are hatched from the eggs and become adults only after 18 molts.

The subclass Cephalocarida was discovered in 1957. Its first identified representative, Hutchinsoniella macracantha, was found on the Atlantic coast of the USA. Other species have been found on the eastern and western coasts of North America and near Japan. Three genera, embracing four silt-dwelling species, are known.


Zhizn’ zhivotnykh, vol. 2. Moscow, 1968.
Dogel’, V. A. Zoologiia bespozvonochnykh, 6th ed. Moscow, 1975.


The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
Details of morphology, phylogeny, physiology, and ecology are then presented for the class Cephalocarida, class Remipedia, subclass Hoplocarida, and superorder Syncarida.
Editors and authors cover class Branchiopoda, Cephalocarida, Maxillopoda, Ostrocoda and Malacostaca, with changes from the last edition of 1989, a list of endangered crustaceans in North American and Hawaii and those presumed extinct, and a recounting of the literature cited.
Naked sensory cilia of presumed chemosensors of other crustaceans, Hutchinsoniella macracantha (Cephalocarida) and Pachypygus gibber (Copepoda), have been shown by TEM, and in the former case also by SEM, although the documentation is not of the highest quality (Hipeau-Jacquotte, 1986; Elofsson and Hessler, 1994).
Sensory structures associated with the body cuticle of Hutchinsoniella macracantha (Cephalocarida).
Extant members of the Cephalocarida retain this system, but almost all other recent species have at least three pairs of mouthparts, i.e., mandibles (Md), maxillae 1 (Mx1), and maxillae 2 (Mx2).
Members of the class Cephalocarida are the most primitive living crustaceans, on the basis of comparative studies of the external morphology, skeletomusculature, larval development, and behavior of the best-known species, Hutchinsoniella macracantha (Sanders, 1957, 1963; Hessler, 1964, 1992; Hessler and Newman, 1975).
Amongst the other classes of crustacea, namely, Branchiopoda, Cephalocarida, Maxillopoda, Ostracoda, and Remipedia, only the last named has not been examined for its muscle fine structure.