KONGL. sv. VET. AKADEMIENS HANDLINGAR. HAND. 34. N:o 2. 29 



Tliis spccies was found in May and June 1898 abundantly al tli<' Färöes, less 

 coinmon there in July. 



Lithodesmium andniatum Ehb. — July: Helder r. August: I 'Kin. r. September: 

 Helder c. 



Navicnla membranacea Cl. — February: St Vaast vt. April, Ma;/: E. of Scotland rr. 

 Nitzschia delicatissiina Cl. — April, May: 56° N. 7° K. +. 



N. seriata Cl. — February: Måseskär +. March: Skagerak and Väderö r. April, 

 Mii//: X. and E. of Scotland; S. of Norway r; \\ . Skagerak r; 55 X. l> E. r. 

 Tliis species was seen in 1898 October at 61°— 63° N. 5°— 10° W. (/•). 



Rhizosolenia alata Btw. — April, May: 57° — 60° N. 1° E. r. August: Skagerak rr. 

 October: Plym. r. 



R. atlantica H. Per. — November: W. of Jutland and in t lie Skagerak rr. 



R. calcar avis Schulze. — April, May: Skagerak and Måseskär r. July: off Ileligo- 

 land and W. of Denmark r. August t<> December: Skagerak, Väderö and Måseskär r. 



R. (alata var.) corpulenta Cl. — July to October: Plym. + c. 

 R. delicatula Cl. — February: St Vaast rr. 



R. (alata var.) gracillima Cl. — May: 58° N. 3° E. +. June: Skagerak rr; Mäseskär + c. 

 Ju///, August: Plym. cccr; Irisli Channel c; N. of Jutland c; Skagerak rr; Väderö + r; 

 Måseskär + cc. September to December: Skagerak, Väderö and Måseskär + r. 



R. robusta Norm. — January: Plym. /•. March: Plym. r. August: Plym. r. Sep- 

 tember: Plym. c. November: 55° N. 6° E. r. 



R. obtusa Hensen. — March: Maseskär rr. Ma//: 61° N. 1° E. r. 



R. semispina Hensen. — January, February: Väderö and Måseskär r. Mardi: 

 Skagerak, Väderö, Måseskär er. April, May: 61° N. 1° E. r; round Seotland r; 58° N. 

 4° E. c; N. of Jutland c; Väderö and Måseskär c +. June: Måseskär r. July: W. of 

 Denmark +. 



This aretie species was seen in October 1898 S. of Iceland, in Mardi 1899 abun- 

 dantly at 49° N. 9° W. and in April at 49° N. 7° W. 



R. setteera Btw. — February: St Vaast rr. Marek: Helder r; Skagerak r. April, 

 May: E. of Scotland r; Skagerak r; Helder r. September to December: Skagerak + /■. 



