358 



TAOIO SK(l(lSItKI(i; 



The plankton 

 imtslignlionf. 



Tills residt is ubvituisly di'tiiiiti'ly o|)|Kist.'il in the view quoted iibovc as bi'Uiy [)ut loiward 

 l)v C. Al'STElN, Ittll. that P/i. (Pit.) t/lobusa has a siuglo planktonic copulation period liiiiitcd 

 to the mouths of April, May and .luiu'. 



On ari'oimt «)f this 1 carried out new investigations concerning this prohlcin. In the (list 

 place 1 investigated aboni a liundnd plankton samples, taken during January, February, May 

 and July at Skager Rak and Cattegat by the investigation vessel ,,S k a g e r a k" for the 

 ,,S\veilish Hydrographical Biological Commission". Secondly the ])lankton tables publislied 

 by the ,,("onseil permanent international pour I'exploration de la mer", on which C. Al'STEIN 

 had founded his view, were subjected to a renewed and careful investigation. 



The results of the first investigation seemed to support the view put forwaixl byAPSTEIN, 

 In all the samples from January, February and July this species was quite absent. Only in 

 a few samples from the month of May, consequently within the period suggested by APSTElN, 

 did I succeed in finding it. Both males and females were discovered. This is interesting because 

 the literature so far published does not clearly show whether both sexes are found swimming 

 freelv in the hiL'her la vers of the water. The results are shown in the following: table: 



The small number of females seems to indicate that the females return to the bottom 

 more rapidly than the males. 



The following are the results of my re-examination of the plankton tables published b}- 

 the ,,C o n s e i 1 permanent": 



Philomedes (Ph.) globosa is stated in these tables to have been caught at the following 

 stations on the following occasions: (The same terms are used in my work as those in these tables: 

 cc means very common, c common, + „neither common nor rare", r rare, rr very rare, — means 

 that the species was not found). 



1903: May: Da 7, lat. 57" 52' N., long. 11" 18' E., depth to the bottom = 87 m. 

 2. v., 1 l> 10 a. m. — 2 li 20 a. m. 

 75 m. — 45 ui. rr. 

 65 „ — „ + 

 10 „ ~ „ rr. 

 „ +. 



