KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 35. N:0 5. 55 



find, in the same specimen, all transitions from the curved spinulose awns of Lauder's 

 species to the less spinulose and less curved awns of my C. rudis, which thus must be 

 considered identical with C. coarctatus. It is remarkable that this species always is accom- 

 panied by a small Zooxanthella. 



Chsetoceros compressus Lauder. 

 There seems not to be any specific difference between this form and C. con- 



tOrtUS SCHUTT. 



Chsetoceros curvisetus Cl. 



This species seems me now not to differ specifically from C. secundus Cl., the 

 latter being somewhat coarser and less curved. Specimens from the Malay Archipelago 

 scarcely differ from those of the North Sea. Both are thus to be united under 

 the name of C. secundus, but the narae C. curvisetus is of so frequent use that I prefer 

 the latter. 



Chsetoceros distans Cl. 



This form has a single chromatophore, parallel to the pervalval and sagittal axes. 

 It seems to be very nearly related to C. Ostenfelclii Cl., from which it differs in shorter 

 cellules. It is, besides, considerably larger, but if these differences are sufficient for 

 specifical distinction must be left to future researches. 



■■ ' \ i' . : ■( 



Chsetoceros furca Cl. ' ' ' '^ 



This species has a single chromatophore-plate extended in the direction of the sagittal 

 and pervalval axes. 



Chsetoceros paradoxus Cl. '" 



The chromatophore is single and extended along the zone. The width of the fora- 

 mina is somewhat variable. . ,, 



Chsetoceros Ralfsii Cl. 



This species has a single chromatophore-plate extended in pervalval and sagittal 

 direction and is nearly alkin to C. javanicus Cl. {— C. Schtlttii Cl.). 



Chsetoceros Weissflogii ScHL TT. ' ' 



I have above classitied as Cluctoceros Weissflogii a diatom, which was found in 

 several samples from the Malay Archipelago. The determination is doubtful, as no spoi-es 



