68
R. E. DELL
doubtedly attracted more comment than any other Antarctic species.
It is the species which has been known as Hexalasma antarcticum, which
Newman and Ross (1971) have shown to be based on the adult form of an
earlier described species, now B. corolliforme (Hoek). These authors
have also shown that this group of corolliforme, the New Zealand
Miocene B. aucklandicum (Hector) and the North Atlantic B. hirsutum
(Hoek), are so different from Hexelasma that they warrant a, new
genus, Bathylasma. The suborder Balanomorpha is usually divided
into two families, the Chthamalidae and the Balmidae. There has
always been uncertainty about in which family Hexelasma and its allies
should be accommodated. Newman and Ross (1971) believe that these
genera are distinct enough to require a new family, the Bathylasmatidae. Growth of knowledge of what we must now learn to call Bathylasma corolliforme has been slow, contributors following the tradition of
scientific interdisciplinary effort in the Antarctic. Borradaile (1916b)
described it from disarticulated valves collected as subfossils in a glacier
deposit about 9 m above aea level in the Ross Sea. It has been one of the
central points in the discussions concerning the methods by which
organisms of many groups have been exposed on the surface of ice,
which has ranged from Debenham (1919) to Debenham (1961) and
thence into the discussions on anchor ice formation.
Dead valves have been dredged in quantity on occasions and Utinomi (1965) and the geologist Weisbord (1967) have given recent
accounts. Bage (1938) had a live specimen but most other accounts of
this barnacle had been based upon dead valves. Some of Weisbord’s
specimens from the Scotia Ridge gave an age of 17 000 f 360 years
and would therefore be Pleistocene. Bullivant (1967, p. 66, pl. 14, p. 50)
described a “ Barnacle-plate Bottom ” in the Ross Sea with many live
specimens. Here on the northern edge of the deep shelf in the Ross Sea,
“ Hexelasma antarcticum covers exposed erratics thickly and the dead
plates have built up a deposit comprised of very little else, with almost
no fine sediment ”.
This station was New Zealand Oceanographic Institute Sta. A463,
7Z020’S, 174O50‘E, in 468 to 465 m. A similar bottom was recorded
from the nearby Station A465 in 399 m. The U.S.S. Glacier sampled a
similar assemblage about 18 miles west of Station A463, in 521 m. It is
evident that a fairly extensive bed of Bathylasma occurs along the edge
of the deep shelf, in an area where the lack of h e sediment indicates
strong bottom currents in depths from about 400 to 550 m. Now that
it has been shown that corolliforme and antarcticum are synonymous, as
Weisbord (1965) had indicated might well be true, it is possible to
assess its distribution. It would appear to be circumpolar in high
R. E. DELL
doubtedly attracted more comment than any other Antarctic species.
It is the species which has been known as Hexalasma antarcticum, which
Newman and Ross (1971) have shown to be based on the adult form of an
earlier described species, now B. corolliforme (Hoek). These authors
have also shown that this group of corolliforme, the New Zealand
Miocene B. aucklandicum (Hector) and the North Atlantic B. hirsutum
(Hoek), are so different from Hexelasma that they warrant a, new
genus, Bathylasma. The suborder Balanomorpha is usually divided
into two families, the Chthamalidae and the Balmidae. There has
always been uncertainty about in which family Hexelasma and its allies
should be accommodated. Newman and Ross (1971) believe that these
genera are distinct enough to require a new family, the Bathylasmatidae. Growth of knowledge of what we must now learn to call Bathylasma corolliforme has been slow, contributors following the tradition of
scientific interdisciplinary effort in the Antarctic. Borradaile (1916b)
described it from disarticulated valves collected as subfossils in a glacier
deposit about 9 m above aea level in the Ross Sea. It has been one of the
central points in the discussions concerning the methods by which
organisms of many groups have been exposed on the surface of ice,
which has ranged from Debenham (1919) to Debenham (1961) and
thence into the discussions on anchor ice formation.
Dead valves have been dredged in quantity on occasions and Utinomi (1965) and the geologist Weisbord (1967) have given recent
accounts. Bage (1938) had a live specimen but most other accounts of
this barnacle had been based upon dead valves. Some of Weisbord’s
specimens from the Scotia Ridge gave an age of 17 000 f 360 years
and would therefore be Pleistocene. Bullivant (1967, p. 66, pl. 14, p. 50)
described a “ Barnacle-plate Bottom ” in the Ross Sea with many live
specimens. Here on the northern edge of the deep shelf in the Ross Sea,
“ Hexelasma antarcticum covers exposed erratics thickly and the dead
plates have built up a deposit comprised of very little else, with almost
no fine sediment ”.
This station was New Zealand Oceanographic Institute Sta. A463,
7Z020’S, 174O50‘E, in 468 to 465 m. A similar bottom was recorded
from the nearby Station A465 in 399 m. The U.S.S. Glacier sampled a
similar assemblage about 18 miles west of Station A463, in 521 m. It is
evident that a fairly extensive bed of Bathylasma occurs along the edge
of the deep shelf, in an area where the lack of h e sediment indicates
strong bottom currents in depths from about 400 to 550 m. Now that
it has been shown that corolliforme and antarcticum are synonymous, as
Weisbord (1965) had indicated might well be true, it is possible to
assess its distribution. It would appear to be circumpolar in high