IvONtiL. SV. VET. AKADEMIENS HANDLINGAR. BAND 34. N:0 I. 21 



the an^^les, all turned in an aii^le of 15 20 towards the longitudinal axis, thinner 

 and stronger intermingled. Terminal awns very long, stronger than the others, angular, 

 with spirally arranged small spines, which become stronger towards the distal end. 

 Endocysts in tlic middle of the cellules, biconvex, covered with numerous, long bristles. 



Longitudinal axis 0,oi2 to 0,02s. Sagittal axis 0,o2 to 0,025. Endocysts 0,oo9 to 0,oi2 

 long. Their sagittal axis 0,o2 to 0,025 millim. This species was found in March 1898 at 

 7N., ^:rW. (Temperature 25,y.) 



This species is well distinguished from all known forms by the absence of foramina, 

 by tlic direction of tlie awns bv the endocysts and the size. In the absence of foramina 

 and the direction of the awns it reminds of the very small form, which I have named 

 C. mbtilis (Bih. till. Kongl. Sv. Vet.-Akad. Handl., Vol. XXIII 3, n:o 5, fig. 8). Another 

 form without foramina I found in plankton from the Caspian Sea. 



Chietoceros Ostenfeldii. N. Sp. 



Plate VIII. Fig. 19. 



Chains flexible, witli large oval foramina, as large as the cellules. Cellules thin- 

 walled, with concave valves, somewhat longer than broad. Awns thread-like, short. 

 Terminal set;e stronger than the others. Cell-contents (as far as could be ascertained on 

 alcohol-preserved specimens) with one chromatophore along the wall of the zone. 



Longitudinal axis of the cellules 0,oi. Sagittal axis 0,oo7 millim. 



This form has a considerable resemblance to C. laciniosus Schutt, but is much 

 more delicate and has a single chromatophore. It lias been distinguished by Ostenfelu 

 .(lagttagelser over overfladsvandets temperatur, saltholdighed og plankton, in 1898) as 

 C'. laciniosus ojf'.i^ 



It was observed in April 1898 abundantly at 49 48 N., I9 29\V., rarer in 

 the Irminger Sea and the FSrOe Channel, but became there common in May. Later it 

 was seen only rarely, but in August it was found abundantly between Iceland and 

 Greenland. 



Dactjiiosoleii hyaliuiis. N. Sp. 

 riatc VIII. Fig. 33. 



Cellules cylindrical, 1' 2 to 2 times longer than broad, tirnjly iniited into confervoid 

 threads. Valves circular flat, without any visible structure and Avith simple, not crenulate 

 margins. Zone with numerous transvei-se rings, 2 in O.oi millim., not distinctly punctate. 

 Chromatophores small. Length of the cellules (),ot! to 0,on, their diameter 0,o-t millim. 



This species was found from February to June 1898 in the region of the New- 

 foundland Banks, associated with species belonging to styli-plankton. It reappeared on 

 the same area in November. Temperature 14,4, mean of 32 obs., max. 20, min 8. Sali- 

 nity 3.J, mean df 27 ol)s., max. 3(i,4ii, min. 32,62. 



