GENERAL 227 



The species of Scalpelbim were collected in the so-called Southern Ocean and the 

 southern part of the Atlantic Ocean. The localities are grouped round the Falkland 

 Islands, Palmer Archipelago, South Georgia, Elephant and Clarence Islands, and Tristan 

 da Cunha, which latter locality is the most northerly for the genus Scalpellum in this 

 collection. These species therefore belong to the so-called Antarctic and sub-Antarctic 

 regions of which the limits are not uniformly regarded by different authors. By 

 some, e.g. Weltner, the northern limit for the sub-Antarctic is set at 40° S, a very unnatural 

 limit, and not in agreement with the principles of modern zoogeography. By later 

 authors, South Africa, South Australia and New Zealand are not held to belong to 

 the sub-Antarctic region. In consequence of this lack of uniformity it is difficult to 

 determine how many species of Scalpellum are known from the Antarctic and sub- 

 Antarctic regions. Some species are known also from parts near to the northern limit 

 here mentioned, and if these are included about twenty-six species of Scalpellum are 

 known from both these regions. 



It is not possible to decide whether they are distributed over the whole area in which 

 the Discovery material was collected, as only a few finds of each species are known. 

 Of these twenty-six species, only three were rediscovered by the Discovery expedition, 

 namely, S. gibberum, C. W. Aurivillius, 1892, S. africanum, Hoek, 1883, and S. con- 

 vexiim, Nilsson-Cantell, 1921, all from previously known localities. As the other three 

 species are new to science, we must admit that our knowledge of the Cirripedes from 

 these parts of the ocean is incomplete. Since some, such as S. elongatum, Hoek, 1883, 

 are known also from New Zealand waters, it is possible that others have a wider distri- 

 bution. S. ventricosiim, Hoek (1907), 1913, noted by me from the Atlantic Ocean 

 (50° 11' S, 50° 50' W) was first described from a more northern and eastern locality 

 (10° 35-6' S, 124° 1 1-7' E). If other species have such a wide distribution the number 

 of species mentioned above may be much greater. At present, I think it is impossible 

 to give a complete discussion of the distribution of these South Atlantic species of 

 Scalpellum. The details of the distribution of the genera in this collection are given 

 under the descriptions of the species. A comparison may here be made between the 

 species with regard to the depth at which they were found. (Table overleaf.) 



The first eight species in this table are pelagic, occurring on animals and floating 

 objects. The substrata are discussed in detail in the systematic part of this paper. Of the 

 remainder, most were taken from the littoral belt if, in accordance with many authors, we 

 put the limit for this zone at 200 m., and not 400 m. as is done in many works on Cirri- 

 pedes. Surely many occur in the abyssal zone also. For instance, S. convexum, Nilsson- 

 Cantell, 1921, is here noted from 110-236 m. and in the type description from 310 m. 

 H. corolliforme is here taken from 200 m., but was first described from a specimen from 

 deeper water (274 m.). The three new species of Scalpellum are from depths greater 

 than 200 m. 



Many of the species here collected are well known. Still, the collection is of biological 

 and embryological interest. Of some species of Lepas, Scalpellmn and Coronula, rich 

 material was brought home, including young stages. I have followed the principles applied 



