116
R. K. DELL
only the monotypic genus Paracucumis appears to be endemic although
Ekmocz~cumis is largely confined to the Antarctic with five of its six
species endemic (including South Georgia) and the other species
occurring in South Georgia and the Falklands. The other 18 genera are
more or less widely distributed in the oceans of the world. The holothurian fauna is thus fairly generalized. Similarly there is little sign of
species diversity in the group. Considered at the species level, about
58% are endemic (71% if South Georgia is included). Of the remaining
species eight are known elsewhere from South America and Kerguelen,
one from Kerguelen alone, and two from New Zealand and South
America.
Southern South America thus seems to be the main pathway for
holothurian migration. There are no other obvious relationships.
Study of the distribution maps presented by Pawson (1969) makes
it clear that the distribution of Antarctic holothurians is only poorly
known, and Pawson had stated that the most up to date information
available on Antarctic holothurians was Ekman’s paper in 1925. Thus
the collections made over the last 15 years have not been available, nor
have the collections made by some earlier expeditions, notably the
Discovery Collections. It is also obvious that the records for the Subantarctic are much better documented.
Under the circumstances consideration of the distribution of the
holothurians within the Antarctic area is probably not very profitable.
From the fact that a number of species have been recorded from one or
two areas in East Antarctica and from West Antarctica it would seem
fairly obvious that a fair percentage of the typical Antarctic species
will prove to be circumpolar in distribution.
A peculiar member of the Psolidae from off the Antarctic Peninsula
in 2 763 to 2 818 m proved to have a lateral sole instead of the usual
ventral sole as developed in the rest of the family. Pawson (1971)
described this form as a new genus and species, Ekkentropelmac brychia.
R. Ascidiacea
The ascidian fauna of the Antarctic is large and varied. It has been
made known in a long series of papers from those on South Georgia by
Pfeffer (1889) and Michaelaen (1898, 1900) to the series of expedition
reports by Herdman (1902,1910,1912,1923), Sluiter (1905, 1906,1912,
1914, 1932), Hartmeyer (1911), van Beneden and Selys-Longchamps
(1913), Harant and Vernihes (1938), h b a c k (1938, 1950), Kott (1954,
1969a), Millar (1900) and Vinogradova (1962). It is one of the few groups
for which we have a modern comprehensive monograph (Kott, 1969a)
based on most of the recently collected material. Kott (1969b) has also
R. K. DELL
only the monotypic genus Paracucumis appears to be endemic although
Ekmocz~cumis is largely confined to the Antarctic with five of its six
species endemic (including South Georgia) and the other species
occurring in South Georgia and the Falklands. The other 18 genera are
more or less widely distributed in the oceans of the world. The holothurian fauna is thus fairly generalized. Similarly there is little sign of
species diversity in the group. Considered at the species level, about
58% are endemic (71% if South Georgia is included). Of the remaining
species eight are known elsewhere from South America and Kerguelen,
one from Kerguelen alone, and two from New Zealand and South
America.
Southern South America thus seems to be the main pathway for
holothurian migration. There are no other obvious relationships.
Study of the distribution maps presented by Pawson (1969) makes
it clear that the distribution of Antarctic holothurians is only poorly
known, and Pawson had stated that the most up to date information
available on Antarctic holothurians was Ekman’s paper in 1925. Thus
the collections made over the last 15 years have not been available, nor
have the collections made by some earlier expeditions, notably the
Discovery Collections. It is also obvious that the records for the Subantarctic are much better documented.
Under the circumstances consideration of the distribution of the
holothurians within the Antarctic area is probably not very profitable.
From the fact that a number of species have been recorded from one or
two areas in East Antarctica and from West Antarctica it would seem
fairly obvious that a fair percentage of the typical Antarctic species
will prove to be circumpolar in distribution.
A peculiar member of the Psolidae from off the Antarctic Peninsula
in 2 763 to 2 818 m proved to have a lateral sole instead of the usual
ventral sole as developed in the rest of the family. Pawson (1971)
described this form as a new genus and species, Ekkentropelmac brychia.
R. Ascidiacea
The ascidian fauna of the Antarctic is large and varied. It has been
made known in a long series of papers from those on South Georgia by
Pfeffer (1889) and Michaelaen (1898, 1900) to the series of expedition
reports by Herdman (1902,1910,1912,1923), Sluiter (1905, 1906,1912,
1914, 1932), Hartmeyer (1911), van Beneden and Selys-Longchamps
(1913), Harant and Vernihes (1938), h b a c k (1938, 1950), Kott (1954,
1969a), Millar (1900) and Vinogradova (1962). It is one of the few groups
for which we have a modern comprehensive monograph (Kott, 1969a)
based on most of the recently collected material. Kott (1969b) has also