Studies on Limacina inflata d'Orbigny (Thecosomata, Gastropoda) in the Indian Ocean 395
present in all 12 Indian Ocean Standard Net (IOSN) night tows in August and October. As
CBS and IOSN samples were not available from the same station, no definite conclusion
can be drawn as to the efficiency of the gear. However, in the southern latitudes IOSN
samples, too, lack this species.
The diurnal variation of this species is remarkable (Fig. 9 a). There are a few records
of small numbers of specimens, especially during April- August, but most of the day
collections do not contain this species, whatever the latitude and season. Only collections
day
40
•
OL...4.~~~!!--,-.1....10...!
~fLf-1?1
«o-,:::E:::E-,
1962 Months 1963
Fig. 11. Seasonal variation in the mean number of Limacina inflata with % of occurrence
from the northern latitudes between 9
0
and 13 0 S and another at 21
0
S show greater
abundance. This shows that Limacina inflata for most of the year lives below 200 m
during the day in many stations along 110° E.
The mean number of Limacina inflata and its percentage of occurrence with respect
to latitude and month are shown in Figs. 10 and 11, day and night values being shown
separately. In determining the average, either for each latitude or each cruise, single
records of occurrence were omitted in day values, but included in the total. Of all the
latitudes between 9° and 32 ° S, the maximum number of this species was found at 11 ° S
and minimum at 26° S. Of all 6 cruises, the highest percentage was found in July- August
1963, the highest mean number in August-September 1962 and the lowest in JanuaryFebruary 1963 (Fig. 11).
present in all 12 Indian Ocean Standard Net (IOSN) night tows in August and October. As
CBS and IOSN samples were not available from the same station, no definite conclusion
can be drawn as to the efficiency of the gear. However, in the southern latitudes IOSN
samples, too, lack this species.
The diurnal variation of this species is remarkable (Fig. 9 a). There are a few records
of small numbers of specimens, especially during April- August, but most of the day
collections do not contain this species, whatever the latitude and season. Only collections
day
40
•
OL...4.~~~!!--,-.1....10...!
~fLf-1?1
«o-,:::E:::E-,
1962 Months 1963
Fig. 11. Seasonal variation in the mean number of Limacina inflata with % of occurrence
from the northern latitudes between 9
0
and 13 0 S and another at 21
0
S show greater
abundance. This shows that Limacina inflata for most of the year lives below 200 m
during the day in many stations along 110° E.
The mean number of Limacina inflata and its percentage of occurrence with respect
to latitude and month are shown in Figs. 10 and 11, day and night values being shown
separately. In determining the average, either for each latitude or each cruise, single
records of occurrence were omitted in day values, but included in the total. Of all the
latitudes between 9° and 32 ° S, the maximum number of this species was found at 11 ° S
and minimum at 26° S. Of all 6 cruises, the highest percentage was found in July- August
1963, the highest mean number in August-September 1962 and the lowest in JanuaryFebruary 1963 (Fig. 11).