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Paractis alba Studer 1878

Please note: Paractis alba is the original binomen of this species according to Carlgren's 1949 catalog. Nomenclatorial inconsistencies need to be resolved in a future revision of this genus (see below).
Containing group: Actiniidae


Actiniidae with very broad base enclosing shells of Gastropods. Column smooth, fairly broad, with well developed fosse. Sphincter aggregated endodermal (in younger individuals) to chiefly mesogloeal in adults. Tentacles up to about 80, conical, in at least 4 cycles, about half as numerous as the mesenteries. Longitudinal muscles of tentacles and radial muscles of oral disc ectodermal, very strong. Siphonoglyphs irregularly arranged (always?), fairly well developed. Two pairs (or only one pair?) of directives. Several pairs (up to about 20) of mesenteries perfect, an equal number of imperfect mesenteries, all these filamented and sterile. The mesenteries of the last cycle do not reach the margin and are fertile but lack filaments. Retractors and, especially the parietobasilar muscles, weak. Very large basitrichs in all parts of the ectoderm, especially in the column, where they are collected into spots containing a few spirocysts also. Cnidom: spirocysts, basitrichs (microbasic p-mastigophors?).

Other Names for Paractis alba Studer 1878


Carlgren, O. 1949. A Survey of the Ptychodactiaria, Corallimorpharia and Actiniaria. Kungl. Svenska Vetenskapsakadamiens Handlingar, series 4, volume 1, number 1.

About This Page
The information provided on this page is based on Oscar Carlgren's 1949 catalog.
Copyright © 1949 Swedish Academy of Sciences.

Please note that Carlgren's text contains a number of errors, and much of the information is now out of date. An update of the catalog is currently under preparation in Daphne Fautin's laboratory, and the results of this work will be incorporated in future versions of this page.

Keyboarding of Carlgren's catalog was done as part of a project to create an electronic database of the sea anemones of the world, funded by NSF Grant DEB9521819, awarded to Daphne G. Fautin. This grant is in the program Partnerships to Enhance Expertise in Taxonomy (PEET). Susanne Hauswaldt, Katherine Pearson, and April Wakefield-Pagels contributed to the keyboarding effort.

Correspondence regarding this page should be directed to Daphne G. Fautin at

All Rights Reserved.

Citing this page:

Tree of Life Web Project. 2000. Isosicyonis. Paractis alba Studer 1878. Version 01 January 2000 (temporary). http://tolweb.org/Paractis_alba/18358/2000.01.01 in The Tree of Life Web Project, http://tolweb.org/

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