160
R. K. DELL
Dearborn’s collections as reported by him (1967) are obviously
mainly taken from Zone I11 of Dayton, et al.
On volcanic gravel and debris in less than 50-60 m Lineus, Clyptonotus, Limatula, Ophiurolepis geliclu, Ophiacantha antarctica, Odontaster
validus and Diplasterias brucei are amongst the most conspicuous
animals.
Amongst Crustacea the amphipod genus Orchomenella is well represented, 0. pinguides Walker occurring in shallow water while 0. plebs
Hurley and 0. rossi Walker were attracted in their thousands to the bait
in traps. Below 100 m other amphipods such as Epimeria macrodonta
Walker, Epimeriella macronyx Walker, Eusirus microps Walker and
Maxilliphimedia longipes Walker were taken, with the brilliant
crimson-marked Emirus perdentatus Chevreux below 500 m. Six
species of mysids have been identified from these McMurdo Sound
collections together with four species of cumaceans, and a single tanaid
species, Nototamis antarcticus (Hodgson), proved to be extremely common down to about 100 m. In deeper water several species of isopods
occurred, Cirolana intermedia Vanhaffen, C . albinata Vanhaffen, Aega
glacialis Tattersall and several species of Antarcturus.
Amongst the molluscs, a scavenging gastropod Neobuccinum eatoni
was often common in shallow waters. The bivalves Laternula elliptica,
Yoldia (Aequiyoldia) eightsi and Thrmia meridionalis were common
burrowing forms with Limatula hodgsoni burrowing in living sponges
or in the matted dead spicules below. The small bivalve Philobrya
sublaevis lives attached by a byssus to many other fixed animals. The
gastropod Trophon longstafli is another carnivore with the trochoids,
Nargarella refulgens and Antimargarita crebrilirulata (Smith) and small
rissoids like Subonoba and Ovirissoa occurring in countless thousands.
Sponges were present in enormous number and variety, especially
hexactinellids with their long siliceous spicules, together with many
alcyonarians. The other obvious diverse group represented is the echinoderms. Below 60 m the crinoids Promachocrinus kerguelensis and
Anthometra adriani occurred together with two other species. Sterechinus
neumayeri was the only sea urchin taken in the vicinity of McMurdo
Base although three species of the Abatus complex were also collected
elsewhere in McMurdo Sound. Nine species of ophiuroids were collected
together with about ten species of asteroids.
There has always been considerable discussion as to how so many
organisms manage to exist under ice shelves in the Antarctic, especially
such extensive areas as the Ross Ice Shelf. I n addition to the mere fact
of l i e persisting in the sea under thick ice cover, the problem of energy
flow in such environments is of great theoretical interest. Littlepage
R. K. DELL
Dearborn’s collections as reported by him (1967) are obviously
mainly taken from Zone I11 of Dayton, et al.
On volcanic gravel and debris in less than 50-60 m Lineus, Clyptonotus, Limatula, Ophiurolepis geliclu, Ophiacantha antarctica, Odontaster
validus and Diplasterias brucei are amongst the most conspicuous
animals.
Amongst Crustacea the amphipod genus Orchomenella is well represented, 0. pinguides Walker occurring in shallow water while 0. plebs
Hurley and 0. rossi Walker were attracted in their thousands to the bait
in traps. Below 100 m other amphipods such as Epimeria macrodonta
Walker, Epimeriella macronyx Walker, Eusirus microps Walker and
Maxilliphimedia longipes Walker were taken, with the brilliant
crimson-marked Emirus perdentatus Chevreux below 500 m. Six
species of mysids have been identified from these McMurdo Sound
collections together with four species of cumaceans, and a single tanaid
species, Nototamis antarcticus (Hodgson), proved to be extremely common down to about 100 m. In deeper water several species of isopods
occurred, Cirolana intermedia Vanhaffen, C . albinata Vanhaffen, Aega
glacialis Tattersall and several species of Antarcturus.
Amongst the molluscs, a scavenging gastropod Neobuccinum eatoni
was often common in shallow waters. The bivalves Laternula elliptica,
Yoldia (Aequiyoldia) eightsi and Thrmia meridionalis were common
burrowing forms with Limatula hodgsoni burrowing in living sponges
or in the matted dead spicules below. The small bivalve Philobrya
sublaevis lives attached by a byssus to many other fixed animals. The
gastropod Trophon longstafli is another carnivore with the trochoids,
Nargarella refulgens and Antimargarita crebrilirulata (Smith) and small
rissoids like Subonoba and Ovirissoa occurring in countless thousands.
Sponges were present in enormous number and variety, especially
hexactinellids with their long siliceous spicules, together with many
alcyonarians. The other obvious diverse group represented is the echinoderms. Below 60 m the crinoids Promachocrinus kerguelensis and
Anthometra adriani occurred together with two other species. Sterechinus
neumayeri was the only sea urchin taken in the vicinity of McMurdo
Base although three species of the Abatus complex were also collected
elsewhere in McMurdo Sound. Nine species of ophiuroids were collected
together with about ten species of asteroids.
There has always been considerable discussion as to how so many
organisms manage to exist under ice shelves in the Antarctic, especially
such extensive areas as the Ross Ice Shelf. I n addition to the mere fact
of l i e persisting in the sea under thick ice cover, the problem of energy
flow in such environments is of great theoretical interest. Littlepage