. 1 I I [ 1 1 r DEC JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP OCT T 1 f 1 1 r NOV DEC JAN FEB MAR APR Fig- 54- Growth curves of E. superba after Ruud and Bargmann. GROWTH AS INDIVIDUALS AND SWARMS As INDIVIDUALS In illustrating the growth-rate of plankton animals, it is customary to plot the average monthly or half-monthly length of as large a series of measured specimens as possible. Thus Ruud (1932), mainly from specimens collected from whales' stomachs, and Bargmann (1945) from specimens collected from the plankton, obtain the growth curves reproduc
. 1 I I [ 1 1 r DEC JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP OCT T 1 f 1 1 r NOV DEC JAN FEB MAR APR Fig- 54- Growth curves of E. superba after Ruud and Bargmann. GROWTH AS INDIVIDUALS AND SWARMS As INDIVIDUALS In illustrating the growth-rate of plankton animals, it is customary to plot the average monthly or half-monthly length of as large a series of measured specimens as possible. Thus Ruud (1932), mainly from specimens collected from whales' stomachs, and Bargmann (1945) from specimens collected from the plankton, obtain the growth curves reproduced in Fig. 54. Before one year's growth is over, when the adolescents (p. 339, Fig. 95) first appear in substantial numbers in August, Bargmann is able to distinguish between males and females and accordingly from August onwards her growth curve divides into its male and female components. As Fig. 54 shows the growth- rate in the two sexes is very similar, the two curves, although the females are consistently smaller than the males,! following approximately the same course. Ruud does not treat the sexes separately and since he only had substantial larval samples for January, and little or no larval material covering the rest of the year, his curve for the greater part of the first year's growth is largely conjectural, and, as Bargmann (1945, p. 123) points out, in its early stages at any rate, much too steep. In certain broad essentials, however, the two curves agree, both showing at the end of the first year the increase in growth that accompanies the spring blooming of the phytoplankton and both a distinct slowing up 1 See again, however, Fig. 53 which clearly suggests that in a final burst of growth the female overtakes the male. 28-2
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