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Containing group: Mesomyaria


Carlgren's catalog (1949) recognized one genus of Exocoelactiidae, Exocoelactis, containing two species. The names listed above are the original binomina of these species. Nomenclatorial inconsistencies need to be resolved in a future revision of this genus (see below).


Exocoelactiidae: Thenaria (Mesomyaria) with irregular arrangement of tentacles in connection with the bilateral development of the younger mesenteries. After the stage with 12 pairs of mesenteries the later mesenteries arise bilaterally in each sector of the animal, so that the youngest mesenteries appear in the middle of the secondary exocoels. In each pair of the younger mesenteries one mesentery is larger than its partner.

Exocoelactis: Exocoelactiidae with well developed base. Column smooth or somewhat nodular, thick-walled and vase-shaped. Margin tentaculate, undulating or drawn out in 12 or more lobes, which are more or less distinctly marked. Sphincter mesogloeal, weak, so that the upper part of the column cannot cover the tentacles. Tentacles fairly short to short, sometimes thickened on the outer side at the base. At least the 12 first tentacles, and sometimes at least some of those of the third cycle, are typically arranged; the other tentacles are set in two rows, forming triangular groups continuous with one another. The 12 inner tentacles (or a few more) are the largest and lie in the depressions between the disc-lobes. The outer tentacles decrease in size towards the apices of the lobes. The outermost tentacles communicate with the exocoels, the inner with the endocoels. Longitudinal muscles of tentacles and radial muscles of oral disc mesogloeal, at least the former placed near the endoderm. 2 broad siphonoglyphs and two pairs of directives. The pairs of the mesenteries of the 2 first cycles are normally developed, perfect and sterile. Each of the later pairs consists of a larger and a smaller mesentery, arranged bilaterally with the youngest pairs in the middles of the secondary exocoels. The stronger partner in each of these pairs is perfect and may be sterile, all the other mesenteries are fertile. Cnidom: spirocysts, basitrichs, microbasic p-mastigophors.


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. Exocoelactiidae. Version 01 January 2000 (temporary). http://tolweb.org/Exocoelactiidae/18793/2000.01.01 in The Tree of Life Web Project, http://tolweb.org/

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