(134 



•I'Adi: SKOGSIiKliG 



Do the mature male. 



die comparati\'eli/ 



soon? 



same i\uinbor l)otli in tlu' August sainplo and the Fobruary one. Thus in tin' August sample 

 there were 13 J and 14 +, in the February sani])I(> 108 o iuul 96 9- This observation agrees 

 very well with (J. H. FOWI.HH's result. On the otlier hand there were in my samples a far 

 greater number of males than females in the second larval stage. The explanation of this pheno- 

 ineni'n certainly seems to be that the females of this stage, on account of their small size, passed 

 through tlu- 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. FowLEU's 

 result above. Males and females presiunably 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 

 considerable variation. In the August sample the males predominate, in sample 1 even almost 

 in the proportion of 2,5 : 1 and similarly in sample II of February; in sample I of the latter month 

 both sexes are almost equally represented and in samples III and IV of this month the females 

 are very strongly [in-ildininant. See also below. 



What is the cause of this variation? Do the males die comparatively soon after 

 attaining maturity? The fact 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 R a k and Cattegat: 



North Koster; 2. II.: Depth, 30 m.: very rare (only one specimen). Depth, 65 m. : very 

 common; R. M. 8. 331. South Koster; I. II.: Depth, 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 in.: very common. Depth, 140 m. : very common 

 (= 316 specimens); R. M. S. 335. Vaderoarna (off Fjallbacka); 6. II.: Depth, 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. Hallo (N. of Lysekil); 7. II.: Depth, 30 m. : common; 

 R. M. S. 339. Depth, 65 m.: rare; R. M. S. 340. Maseskar (S. of Lysekil); 8. II.: Depth, 

 30 m. : very rare; R. M. S. 341. Pater Noster (Marstrand); 8. II.: Depth, m.: very rare 

 (only one specimen); R. M. S. 342; Depth, 30 m. : very rare; R. M. S. 343. Vinga (Goteborg); 

 9. II.: Depth, 30 m. : very rare; R. M. S. 344. — All these samples were taken by the 

 Swedish Hydrographical Biological Commissi on 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 — m. : 24 matiire males, 10 mature females and 16 juvenes; R. 

 M. S. 379. Lat. 58" 20' N., long. 10" 5' E. (= S. VII.); 10. VIIL; 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. VIIL: 3 mature males, 8 mature females and 6 juvenes; R. M. S. 380. 

 (Partly -= the material of P. T. Cleve, 1903.) 



Coast of Norway: 



Lofoten Islands; coll. et determ. G. 0. SarS: 17 mature males and 102 mature females. 



