10. GROWTH, MATURITY AND MORTALITY
297
produced and in some years, therefore, the fecundity may be greater
than in others. Further, there may be some latitudinal variations in
the fecundity of a species owing to more time being required for the
animal to become sexually mature in some sea areas than in others and
1 abdominal
phatophore
20
II th
--..-Yo
10 th 3 telson spines
.
.
.
.
,
.
,
.
I
0
I
I
I
40
I
9th
5 telson spines
I
' ; I r d
I
120c
2nd
1
8 t h
Antenna adult
I
I
2
3
4
5
6
7
8
9
Total length (rnrn)
FIO. 113. Length/frequency histograms of the furciliae of Thysanobsa raschii. (After
Mauchline, 1965%)
also owing to possible differences in the duration of the breeding season
in different areas. The evidence available for making these suggestions
will be discussed after we have examined the growth rates of the
different species.