. SOO 1000 0- C M - 298 286 361 ~ ^ C M 50- C M - 1305 373 20 _ _ C M 100- C M 12 6548 21 94 38 5 C M 250- C M 10 889 36 I50 32 31 C M C M 3 17 547 2318 23 69 282 3702 6 2! 1 17 C M 750- C M 15 146 2573 14 165 7 577 144 - C M Fig. 8. Pseudo-diurnal vertical migration. The four-hourly vertical distribution of the First Calyptopis based on the aggregate of the catch-figures shown in Fig.^6. disturbing influence of the deep moulting of the Metanauplius upon the results, must end up in a picture that in some respects is illusory. For such an illustration must inevitably include large numbers of la
. SOO 1000 0- C M - 298 286 361 ~ ^ C M 50- C M - 1305 373 20 _ _ C M 100- C M 12 6548 21 94 38 5 C M 250- C M 10 889 36 I50 32 31 C M C M 3 17 547 2318 23 69 282 3702 6 2! 1 17 C M 750- C M 15 146 2573 14 165 7 577 144 - C M Fig. 8. Pseudo-diurnal vertical migration. The four-hourly vertical distribution of the First Calyptopis based on the aggregate of the catch-figures shown in Fig.^6. disturbing influence of the deep moulting of the Metanauplius upon the results, must end up in a picture that in some respects is illusory. For such an illustration must inevitably include large numbers of larvae which, although to all appearances migrants into deep water from the surface, could never in fact have been anywhere near the surface at all. Fig. 8 in short provides a typical example of the many pitfalls oceanography falls heir to through the employment of nets that do not go deep enough. For if the lower limit of observation in this instance had been say 500 m. there would have been no reason to suppose that the orthodox pattern of rhythmic diurnal vertical migration it manifestly presents was anything other than real, or to doubt that the First Calyptopis made a daily descent into the warm south-flowing core of the deep current running counter to the surface stream. That the picture is not in fact real, but partly an illusion created by the presence of recently born, and still climbing First Calyptopes rising from below, can clearly be established if the dawn to dawn vertical distribution of the combined Calyptopis stages be based, as in Fig. 9, upon data drawn from stations where the First Calyptopis^ occurred free, that is, not in association with deep-mouhing Metanauplii, thereby excluding any possibility that deep, still climbing, Calyptopes could enter into and prejudice the resuh and making reasonably sure that the Calyptopes as a whole, the developmental ascent having been accomplished, had definitely reached the surface. Worked out in this way the vertical exte
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Keywords: ., bookcentury1900, booksubjectocean, booksubjectscientificexpediti
