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Macrocypridia.
Homarus.
Carcinus.
This writer’s investigations with regard to Macrocypridina, Homarus and Carcinus gave
the following results:
Cypridina (Macrocypridina) castanea G. S. Brady.
Only five specimens were recorded; they measured 6,0, 4,0, 1,9, 1,8, and 1,8 mm.
„Apparently three stages, L, IL, and IV., were represented in the five specimens; with
a growth-factor of 1,5, the lengths 1,8, 2,7 (missing), 4,0, and 6,0 are related as in the other
species“ (p. 279).
Homarus americanus Milne Edwards.
This investigation is based on the statements as to length given by F. H. Herrick in
the work of 1896 quoted above. The result of this study quite coincides on the whole with
the resuit previously obtained by F. H. Herrick, cf. p. 125 above. It is noteworthy,
however, that G. H. Fowler pointed out that there must be a difference between the
early, larval moults and the moults at a more advanced âge, p. 280: ,,If a lobster
con-tinued to moult at the same brief intervals, and to grow by the same incrément as
did HERRICK’s larvae, it would be 10% inches long at the end of its first year (instead of
2 -3 inches), and in five years would be a dangerous monster of portentous size.“
Carcinus maenas Leach.
G. H. FOWLER based this investigation on measurements of the greatest breadth of the
carapaces that were thrown ofï by eleven individuals kept in aquariums; the
measure-ments were previously published by H. C. WILLIAMSON, 1903. „The observed breadths
seemed... to fall into groups round obscure médians.“ Although the average values for
these classes of breadths seem to be anything but certain, they agréé in quite an
amazing way with BrOOKS’s 1 a w. In the following table the left row represents „the
means of these vaguely indicated groups“, the right row „the successive products, by an
empirically - found growth-factor, of means starting from 4,80, the lo west observed mean
of the series“ (p. 281).
4,80 4,80 X 1,27 = 6.09
6,05 6,09 X 1,27 - 7,73
7,75 7,73 X 1,27 = 9,81
9,61 9,81 X 1,27 = 12,45
12,65 12,45 X 1,27 = 15,81
16,02 15,81 X 1,23 = 19,44
19,50 19,44 X 1,23 = 23,91
23,89 23,91 X 1,23 = 29,40
29,30 29,40
As will be seen from the above table G. H. FOWLER was of the opinion that in this case
too a smaller growth-factor could be observed for older stages. For more details see this author’s
account, pp. 280, 281,
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