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The Pennatulacea of the Siboga expedition

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distance apart of the small calices, the absence of definite teeth to the calyx, the reddish brown colour and the very slender form they are very different.

It is difficult to determine whether the differences between the specimens from Station 45 (depth 794 metres) and those from Station 271 (depth 1788 metres) are racial or environmental. It will be observed that there is a great difference in the depth of water from which they were obtained. It might have been anticipated that the forms from deeper water would have their calices further apart and not so well developed; but this is not the case, it is the specimens from the shallower water that have the smaller and more distant calices.

The two very young specimens from Stations 35 and 85 are much more closely related to the specimens from Station 271 than they are to those from Station 45.

The smaller one from Station 85, 17 mm. in length, has three calices on one side of the rachis and two on the other, the largest of these calices is 3 mm. in length. The stalk is damaged.

The other specimen from Station 35, 32 mm. in length, has a rachis of 13 mm. and a stalk of 19 mm. but the end of the stalk is also broken off. There are six prominent calices

on each side.

Both specimens are white in colour.

There can be no question that these two small specimens belong to the same species as the larger specimen from Station 271. The only question is whether the specimens from Station 45 and the smaller specimen from Station 271 are distinct. It is only after very careful consideration of the variations that occur in the course of the rachis of the larger specimen from Station 271 and a comparison of these variations with thé other specimens that I have come to the conclusion that they are not distinct.

Family Chunellidae Kükenthal. Chunellidae Kükenthal 1902. Zool. Anz. XXV, p. 302.

Chunellidae + Scleroptilidae Jungersen 1904. Pennatulidae. Ingolf Exped., p. 8.

Chunellidae + Scleroptilidae Kükenthal and Broch 1911. "Valdivia" Pennatulacea. pp. 265,270.

The family Chunellidae was established by Kükenthal in 1902 for certain remarkable

sea-pens (arranged by him in two genera) that were found by the "Valdivia" expedition in deep

water off the E. coast of Africa. He considered that this family was so far distinct that it should

be set apart in a separate Section of the Pennatulacea which he named the Verticilladeae. In

their magnificent memoir on the Valdivia Pennatulacea, however, Kükenthal and Broch changed

the name of the Section to Pennatulacea verticillata and included in it the families Scleroptilidae

and Umbellulidae. The section according to their system is arranged as follows: —

( Genus Calibelemnon .Family Scleroptilidae . . j Qenus Schroptüum

l Genus Amphiacme Family Chunellidae . . . j Qenus Chunella

Family Umbellulidae . . . Genus Umbellula.