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Protoscenium simplex (Cleve, 1899)

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Protoscenium (?) simplex:
Bars thin, cylindrical, each divided at the distal end into three branches, connected by thin threads into a delicate polyhedral network (Diam. 0.06 mm).
(Cleve) 1899
Plectanium simplex:
Cfr. the description of the genus and the introductory remarks.

Each of the primary branches of the main spines has, as already mentioned, near their end, a verticil of 3 branches, of which the two are the connecting arches mentioned above, the third being a short spine about equal in length to the free end of the branch. This spine may - as above mentioned - be connected with one of the approximate corresponding ones, or with the protruding part of the main spine, by exceedingly fine arches.

Here and there on the outer arches fine byspines are found, which are perhaps partly developed into such hair-like connecting arches.

The species is no Plectanium in Haeckel’s sense. Cleve draws the apical spine as protruding from the common starting point of the basal spines, and has, probably for this reason, classed the species as belonging to HCK's genus Plectanium.

I have seen only a few individuals of this species; but I have, nevertheless, no doubt that its characteristic structure in all important points is as above described. Older individuals have, perhaps, a more richly developed network of added, secondary arches.

Rare and only singly: 19/1 1899, 40 miles NW of Gaukværø, 0-700 m. Is, however, easily overlooked.

Distribution: Only noticed by Cleve from two places: 78° N, 3° W, deep sea haul; 56° N, 36° W. Probably also boreal oceanic.
Jørgensen 1905


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