HIATOMACI- K — l{HI/OS()LKMA Mi 



Scpiriii/x'/-: &2 N. 1 I',., very coiiimon ; (if) N. 1 \\'.. vcrv 

 conimoii deop i^ea haul Iroin 1(H) — ni.. inaxiimiiii at ;")() 

 m.) 6(r — ()7' N. 2 — ;V' W., not common or rare. 



Temperature: li.i, mean of Jti ohs., max. 21.4, mm. ;'>.;! 

 (only siuli obseivalion.'^ considered as relate to samples contaiiiiiiu 

 lliis f(irni abundantly). 



Salinity: HI.ts, mean oF li obs., max. 'M.-j-,, nun. 30,.;^. 



Plankton-type. I have found this form in samples from the 

 lied Sea. It occui-s more or less sparinj^dy in the E(|uatoriaI. An- 

 tilles and Florida Currents. Its principal area of distribution is tlu 

 area between the Azores, the west coast of Europe and the Faroe 

 (ihannel. I never found it c'fl)undantly in the North Sea, but in IIk 

 Skajjerak and alony- the Scandinavian coast it occurs durinji' tlu 

 summer in yreat abundance. As it occurred in September 1K99 very 

 abundantly in the deeper water-layers at &2^ — 65^ N. 1° E. — 1' 

 W., there is reason to believe that it arrives into the Skagerak 

 through the »Norske llendo^. It seems thus to follow the 200 metre 

 j)lateau round the French and l^ritish coasts. In some years it pm- 

 cedes so far as otT lieeren Island, where it was fduiid abundantlv 

 in September 1S{)(). — A'///. -S. 



RHIZOSOLENIA GRACILIS II. K S\iiTn:>' 



(PKitA.iM.ic: \a' Diatoiniste 185)2 I'l. XVI fig. 17. i 

 1X98 Anf/iis/ and Xdrrmhcr: Azores, abundant. 



Temperature: ls..^. 



RHIZOSOLENIA HEBETATA I!aii.. 



I'khv..al.i.(i: le Diatoinisb' 1892 PI. XVII lig. in. 



1S9S Mui-ch: (il .\. ■) \V. 

 Aliril: oit N. jo W. 



' Seems to he a dwarf form df /.'. .<riiiici-ti. 



