ANTARCTIC BENTHOS
75
“From that date until 25th October 1902, this species was taken in
numbers varying between 10 000 and 30 000 at a haul, and this at all
depths to 125 fm.”
Hodgson was of the opinion that these great masses normally fed
on the carcases of seals which had died when unable to find a breathing
hole in the ice.
The amphipod Bovallia gigantea (Pfeffer): The life history of this
large (up to 60 mm) reddish amphipod has been studied in the South
Orkneys by Thurston (1968). Bovulliu gigantea has been recorded from
the Antarctic Peninsula, the South Shetlands, and South Sandwich
Islands, and South Georgia, as well as from the South Orkneys, from
low water mark down to about 40m. It has been commonly found
associated with the large algae Desmarestiu anceps Montagne and
Phyllogigus grundifolius (A. and E. S. Gepp) Skottsberg.
In the South Orkneys it appears to be rather sedentary throughout
the year. Eggs are deposited in the brood pouch in late February and
March, but early development is slow and hatching does not take place
until September and October. As in many other malacostracans, the
number of eggs produced is in direct proportion to the size of the female,
ranging from 80 in a specimen 41 mm in length to 139 in a female
49 mm long. Breeding appears to be seasonal and regular. Females
reach breeding maturity at an age of about 40 months, males at about
28 or 29 months. The evidence available indicates that females die
after the brood is released, though some males may achieve two breeding seasons, dying off after breeding for the second time at about 40
months age.
The general associations of Antarctic amphipods have hardly begun
to be recorded. The necrophagous habits of Orchomenella have been
mentioned. Nine species of amphipods commensal in sponges, and two
species commensal in the branchid chamber of ascidians were listed by
Barnard (1932).
6 . Isopoda and Tanaidacea (Fig. 8 )
The first isopod of Antarctic facies to be described was the Magellanic
Xerolis paradoxa, described by Fabricius (1776) as Onisczcs paradoxa.
The first Antarctic forms proper were described by Eights (1833, 1852,
1866) from the South Shetlands. The Challenger did not obtain any
restricted Antarctic isopods although the reports by Beddard (1884a,
1884b, 1886) supplied a basic knowledge of Southern Hemisphere
members, and Subantarctic species in particular. Pfeffer (1887)
described the collections from South Georgia made by the German
expedition of 1882-83.
75
“From that date until 25th October 1902, this species was taken in
numbers varying between 10 000 and 30 000 at a haul, and this at all
depths to 125 fm.”
Hodgson was of the opinion that these great masses normally fed
on the carcases of seals which had died when unable to find a breathing
hole in the ice.
The amphipod Bovallia gigantea (Pfeffer): The life history of this
large (up to 60 mm) reddish amphipod has been studied in the South
Orkneys by Thurston (1968). Bovulliu gigantea has been recorded from
the Antarctic Peninsula, the South Shetlands, and South Sandwich
Islands, and South Georgia, as well as from the South Orkneys, from
low water mark down to about 40m. It has been commonly found
associated with the large algae Desmarestiu anceps Montagne and
Phyllogigus grundifolius (A. and E. S. Gepp) Skottsberg.
In the South Orkneys it appears to be rather sedentary throughout
the year. Eggs are deposited in the brood pouch in late February and
March, but early development is slow and hatching does not take place
until September and October. As in many other malacostracans, the
number of eggs produced is in direct proportion to the size of the female,
ranging from 80 in a specimen 41 mm in length to 139 in a female
49 mm long. Breeding appears to be seasonal and regular. Females
reach breeding maturity at an age of about 40 months, males at about
28 or 29 months. The evidence available indicates that females die
after the brood is released, though some males may achieve two breeding seasons, dying off after breeding for the second time at about 40
months age.
The general associations of Antarctic amphipods have hardly begun
to be recorded. The necrophagous habits of Orchomenella have been
mentioned. Nine species of amphipods commensal in sponges, and two
species commensal in the branchid chamber of ascidians were listed by
Barnard (1932).
6 . Isopoda and Tanaidacea (Fig. 8 )
The first isopod of Antarctic facies to be described was the Magellanic
Xerolis paradoxa, described by Fabricius (1776) as Onisczcs paradoxa.
The first Antarctic forms proper were described by Eights (1833, 1852,
1866) from the South Shetlands. The Challenger did not obtain any
restricted Antarctic isopods although the reports by Beddard (1884a,
1884b, 1886) supplied a basic knowledge of Southern Hemisphere
members, and Subantarctic species in particular. Pfeffer (1887)
described the collections from South Georgia made by the German
expedition of 1882-83.