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Do the mature males
die comparatively
soon?
same number both in the August sample and tke February one. Thus in the August sample
there were 13 S and 14 $, in the February sample 108 c? and 96 $. This observation agrees
very well with G. H. Fowler’s result. On the other hånd there were in my samples a far
greater number of males than females in the second larval stage. The explanation of this
pheno-nienon certainly seems to be that the females of this stage, on account of their small size, passed
through the meshes of the plankton net in far greater numbers than the males; it is to be noted
that the still smaller larval stages were almost entirely absent in these samples; cf. G. H. FOWLER’s
result above. Males and females presumably occur during the larval period in about a proportion
of 1:1. The proportion between the mature males and females seems to be subject to rather
considérable variation. In the August sample the males predominate, in sample I even almost
in the proportion of 2,5 : 1 and similarly in sample II of February; in sample I of the latter rnonth
both sexes are almost equally represented and in samples III and IV of this rnonth the females
are very strongly prédominant. See also below.
What is the cause of this variation? Do the males die comparatively soon after
attaining maturity? The faet that the February samples are taken at about the same
time and the same locality (cf. below) does not seem to indicate this. But no definite answer
can be given to this question before renewed investigations have been carried out with more
abundant material.
Habitat: — S k a g e r Rak and Catt e gat:
North Koster; 2. IL: Depth, 30 m.: very rare (only one specimen). Depth, 65 m.: very
common; R. M. S. 331. South Koster; I. IL: Depth, 0 m.: very rare (only one specimen);
R. M. S. 332. Depth, 30 m. : very rare; R. M. S. 333. Depth, 65 m. : neither common nor
rare; R. M. S. 334. Depth, 125 m.: very common. Depth, 140 m.: very common
( 316 specimens); R. M. S. 335. Väderöarna (off Fjällbacka); 6. IL: Depth, 0 m.: very
rare; R. M. S. 336. Depth, 30 m.: very rare (only one specimen); R. M. S. 337. Depth,
65 m.: very common; R. M. S. 338. Hållö (N. of Lysekil); 7. IL: Depth, 30 m.: common;
R. M. S. 339. Depth, 65 m.: rare; R. M. S. 340. Måseskar (S. of Lysekil); 8. IL: Depth,
30 m.: very rare; R. M. S. 341. Pater Noster (Marstrand); 8. IL: Depth, 0 m.: very rare
(only one specimen); R. M. S. 342; Depth, 30 m.: very rare; R. M. S. 343. Vinga (Göteborg);
9. IL: Depth, 30 m.: very rare; R. M. S. 344. — All these samples were taken by the
Swedish Hydrograph ical Biological Com mission during a cruise in 1911.
South Koster; 12. VIII.; depth, 150—0 m. : 1 female; R. M. S. 369. Lat. 58° N., long 9° E.
( S. VIII); 9. VIII.: At the surface: 9 mature males, 6 mature females and 11 juvenes;
R. M. S. 378. Depth, 300—0 m. : 24 mature males, 10 mature females and 16 juvenes; R.
M. S. 379. Lat, 58° 20’ N., long. 10° 5’ E. (= S. VIL); 10. VIII.; depth, 150—0 m.:
4 mature males and 24 juvenes in different stages; R, M. S. 370. Lat. 58° 46’ N., long. 10° 25’ E.
( S. X.); depth, 40 m.; 9. VIII.: 3 mature males, 8 mature females and 6 juvenes; R. M. S. 380.
(Partly — the material of P. T. Cleve, 1903.)
C o a s t o f Norway:
Lofoten Islands; eoll. et determ. G. O. SARS; 17 mature males and 102 mature females.
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