Trachomedusae

The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Trachomedusae

 

(also Trachymedusae), an order of marine coelenterates of the class Hydrozoa. The Trachomedusae have eight sex glands arranged along radial canals, and numerous delicate tentacles on the margin of the umbrella. The life cycle lacks a polypoid generation. A planula develops from the egg and is transformed into an actinula-like larva, which metamorphoses into a young medusa. There are approximately 50 species, ten of which are found in the USSR. Aglanta digitale, the commonest species of its genus, is found in almost all oceans. Deep-sea species are reddish or brownish in color and are capable of luminescence.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
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