164
a. K. DELL
the summers of 1958/59 and 1959/60, listed a number of distinct types
of faunal assemblages from the Ross Sea. A good dea1 more work needs
to be done before these proposals can gain general acceptance, and much
more identified material must be incorporated into the data before
Bullivant’s assemblages can be given exactitude. Some identifications
from various published sources have been incorporated into the following summary. Four main assemblages were discussed :
1. Deep Shelf Mixed Assemblage ;
2. Deep Shelf Mud Bottom Assemblage ;
3. Pennell Bank Assemblage ;
4. Minor Assemblages.
1. Deep shelf mixed assemblage
Occurring widely in the Ross Sea and in McMurdo Sound on fine
sediments through which erratic boulders are scattered.
The common animals are tubicolous polychaetes, bryozoans (mostly
rooted varieties), occasional gorgonaceans, various ophiuroids, crinoids,
and other echinoderms and molluscs. Bottom photographs published
by Bullivant (plate 21) showed the general appearance. Animals
identified from a range of the stations listed as belonging to this assemblage, but identified after the publication of Bullivant’s paper include :
Molluscs : Limatula hodgsoni, Cyclocardia astartoides, Thracia
Ophiuroids : O p h i m n t h antarctica, Amphipodia joubini ;
Asteroid : Porania antarctica glabra ;
Pycnogonids : Pycnogonum gaini, Ammothea (Ammothea) glacialis, Achelia (Pigrolavatus) spicata (Hodgson), Austroraptus polaris
meridionalis, Cadulus dalli antarcticus ;
Hodgson.
2. Deep shelf mud bottom assemblage
Occurring at deeper stations on the shelf on a substrate of mud, or
sandy mud, together with erratic boulders. Tubicolous polychaetes are
common, with two species of sipunculid worms (Boljingia margaritacea
capsiformis and B. andersonni), the arenaceous Foraminifera, Rhbdamminu, various ophiuroids particularly Amphipodia joubini, but
including Ophionotus victoriae Bell, holothurians particularly rat-tailed
species, and Umbellula sp. Animals subsequently identified from these
stations include the pycnogonids, Colossendeis lilliei, and C. megalonyx
megalonyx, the coral Plabellum impenaum, the mollusc Dentalium
mujorinum, and the asteroids, Bathybiaster loripes obeaus, Psilaster
charcoti, hidaster gerlachei and Notasterim armata Koehler.
a. K. DELL
the summers of 1958/59 and 1959/60, listed a number of distinct types
of faunal assemblages from the Ross Sea. A good dea1 more work needs
to be done before these proposals can gain general acceptance, and much
more identified material must be incorporated into the data before
Bullivant’s assemblages can be given exactitude. Some identifications
from various published sources have been incorporated into the following summary. Four main assemblages were discussed :
1. Deep Shelf Mixed Assemblage ;
2. Deep Shelf Mud Bottom Assemblage ;
3. Pennell Bank Assemblage ;
4. Minor Assemblages.
1. Deep shelf mixed assemblage
Occurring widely in the Ross Sea and in McMurdo Sound on fine
sediments through which erratic boulders are scattered.
The common animals are tubicolous polychaetes, bryozoans (mostly
rooted varieties), occasional gorgonaceans, various ophiuroids, crinoids,
and other echinoderms and molluscs. Bottom photographs published
by Bullivant (plate 21) showed the general appearance. Animals
identified from a range of the stations listed as belonging to this assemblage, but identified after the publication of Bullivant’s paper include :
Molluscs : Limatula hodgsoni, Cyclocardia astartoides, Thracia
Ophiuroids : O p h i m n t h antarctica, Amphipodia joubini ;
Asteroid : Porania antarctica glabra ;
Pycnogonids : Pycnogonum gaini, Ammothea (Ammothea) glacialis, Achelia (Pigrolavatus) spicata (Hodgson), Austroraptus polaris
meridionalis, Cadulus dalli antarcticus ;
Hodgson.
2. Deep shelf mud bottom assemblage
Occurring at deeper stations on the shelf on a substrate of mud, or
sandy mud, together with erratic boulders. Tubicolous polychaetes are
common, with two species of sipunculid worms (Boljingia margaritacea
capsiformis and B. andersonni), the arenaceous Foraminifera, Rhbdamminu, various ophiuroids particularly Amphipodia joubini, but
including Ophionotus victoriae Bell, holothurians particularly rat-tailed
species, and Umbellula sp. Animals subsequently identified from these
stations include the pycnogonids, Colossendeis lilliei, and C. megalonyx
megalonyx, the coral Plabellum impenaum, the mollusc Dentalium
mujorinum, and the asteroids, Bathybiaster loripes obeaus, Psilaster
charcoti, hidaster gerlachei and Notasterim armata Koehler.