REVIEW OF T H E SYSTEMATICS A N D ECOLOGY O F OCEANIC SQUIDS
111
ventral arms are minute. I n the larger larva (Fig. 7, D) the hole
through the proboscis has become much larger and almost divides the
proboscis into two halves. the tentacles. The proboscis tip bears
about nine pairs of small suckers (Fig. 7 , D). During growth to the
adult, the arms become relatively longer, the head becomes relatively
shorter and the body becomes relatively narrower compared with
the mantle length.
Other examples from the eastern North Atlantic possibly referable to
0. caroli and 0. pteropus have been recorded from the surface to 2 025 ni
with open nets in July to September (Chun, 1913; Massy, 1916a,
1928a: Joubin, 1920, 1924). Okutani (1965) has given a brief description
of larvae referred t o 0. bartrami occurring off Japan.
Once the larval stage is over, change in body form is gradual
(Adam, 1952). Females of 0. caroli become mature (presence of ripe
ovaries and enlarged nidamental glands) at a mantle length of 40.0 cm
and males (presence of spermatophores) at 30.0 cm (Clarke, 1962e).
In 0. pteropus, females become mature at a mantle length of 3 0 4 cm.
As we have caught apparently-healthy females of these two species
which possess spent ovaries it appears that they do not necessarily die a t
spawning; we have, however, no evidence that these survivors spawn a
second time. The greatest size reached by females of 0. caroli known
to the author is 69.0 cm (mantle length) and by males 36.0 cm; that
of 0. pteropus females is 37.0 cm. The sex ratio of 0. cnroli taken in
the North Atlantic by Discovery II is 46 females to 18 males. In
&he West African region the sex ratio of 0. pferopus is 22 females to
13 males (Adam, 1952).
One of the ventral arms is hectocotylized in both these s p e c k hy
103s of suckers from the tip and the development of a slight groove.
Spermatophores are stuck into the buccal membrane of the female.
While the ovaries and nidamental glands suggest that spawning takes
place in late summer and autumn in 0. caroli, spermatophores are
present in males taken throughout the year (Clarke in preparation).
A large 0. caroli probably lays about 360 000 eggs (calculated from the
ovary of one ripe female).
There is no doubt that these species are rapacious predators rapa1)le
of attacking fish and squids the same size or larger than themselvcs.
If one is caught on a hook the other members of the shoal turn on i t
and sometimes badly damage it before it can be pulled in (Figs. 6 and 8).
Such observations belie Steenstrup’s (1 885) contention that 0. pfwopws
feeds on small, weak animals driven into the trap formed by the
arms and their membranes which function rather like a dipnet. Few
stomachs have been examined. An 0. pteropus proved to contain fish.
111
ventral arms are minute. I n the larger larva (Fig. 7, D) the hole
through the proboscis has become much larger and almost divides the
proboscis into two halves. the tentacles. The proboscis tip bears
about nine pairs of small suckers (Fig. 7 , D). During growth to the
adult, the arms become relatively longer, the head becomes relatively
shorter and the body becomes relatively narrower compared with
the mantle length.
Other examples from the eastern North Atlantic possibly referable to
0. caroli and 0. pteropus have been recorded from the surface to 2 025 ni
with open nets in July to September (Chun, 1913; Massy, 1916a,
1928a: Joubin, 1920, 1924). Okutani (1965) has given a brief description
of larvae referred t o 0. bartrami occurring off Japan.
Once the larval stage is over, change in body form is gradual
(Adam, 1952). Females of 0. caroli become mature (presence of ripe
ovaries and enlarged nidamental glands) at a mantle length of 40.0 cm
and males (presence of spermatophores) at 30.0 cm (Clarke, 1962e).
In 0. pteropus, females become mature at a mantle length of 3 0 4 cm.
As we have caught apparently-healthy females of these two species
which possess spent ovaries it appears that they do not necessarily die a t
spawning; we have, however, no evidence that these survivors spawn a
second time. The greatest size reached by females of 0. caroli known
to the author is 69.0 cm (mantle length) and by males 36.0 cm; that
of 0. pteropus females is 37.0 cm. The sex ratio of 0. cnroli taken in
the North Atlantic by Discovery II is 46 females to 18 males. In
&he West African region the sex ratio of 0. pferopus is 22 females to
13 males (Adam, 1952).
One of the ventral arms is hectocotylized in both these s p e c k hy
103s of suckers from the tip and the development of a slight groove.
Spermatophores are stuck into the buccal membrane of the female.
While the ovaries and nidamental glands suggest that spawning takes
place in late summer and autumn in 0. caroli, spermatophores are
present in males taken throughout the year (Clarke in preparation).
A large 0. caroli probably lays about 360 000 eggs (calculated from the
ovary of one ripe female).
There is no doubt that these species are rapacious predators rapa1)le
of attacking fish and squids the same size or larger than themselvcs.
If one is caught on a hook the other members of the shoal turn on i t
and sometimes badly damage it before it can be pulled in (Figs. 6 and 8).
Such observations belie Steenstrup’s (1 885) contention that 0. pfwopws
feeds on small, weak animals driven into the trap formed by the
arms and their membranes which function rather like a dipnet. Few
stomachs have been examined. An 0. pteropus proved to contain fish.