VEGA-EXPEDITION ENS V ET EN S K A P LI G A ARIiETKN. 459 



to trace out the limits of the species. Also were rich, but 

 less interesting materials obtained from algic, collected near Cape 

 Deschnew. Several samples of the bottom-mud from the North 

 Siberian Sea were also taken, but in examining them I could 

 not find a trace of diatoms. All the materials from the expe- 

 dition of the Vega have been examined by myself. Still more 

 materials from the hyperboreal America were collected during 

 the British expedition under the command of Sir George 

 Nares and examined by Mr. G. Dickie ^ Afterw^ards I have 

 received, through the Idndness of Prof. Oliver^ some of these 

 samples. Among them only three were rich enough to be 

 subjected to the usual cleaning-process, viz. from BesseVs Bay, 

 81° r N, Mushroom Point, 82° 28' N, and Discovery Bay, 81° 4i'. 

 The result of my examination of these gatherings are to 

 be found in the following pages. Also from the distant Franz 

 Joseph Land some diatomaceous gatherings have been col- 

 lected on the ice-flakes during the Austrian expedition under 

 Weyprecht. Some of the species found by Mr. Grunow in 

 these materials have been published in Van Heurck's Synop- 

 sis and issued in CI. and Moller Diat. No 314. Mr. Grunow 

 will later publish in a more complete manner his researches 

 in regard to these most interesting diatoms. The materials 

 brought together from the Arctic Sea are thus very considerable, 

 and their examination may give a tolerably complete idea of 

 the (Jiatomaceous vegetation the Arctic Sea. I have therefore 

 tried to give in the following pages a complete list of all the 

 arctic species, found b}^ myself and b}^ Mr. Grunow, omitting 

 those found by other authors, not beeing sure about their 

 determinations. 



Index of marine arctic Diatoms. 

 A. Placochromaticae. 



I. Cocconeidae. 



Cocconeis Sctdelhim Ehb. (Van Heurck Syn. XXIX, 1 — 12) 

 Greenl, Mushroom Point, Fr. J. L. -, Spitsb., Finm., Kara, 

 Cape Deschnew (East Cape). 



^ Jour. Linn. Soc. Vol. XVII, page 6. 



^ F. J. L. Franz Joseph Land according to Grunow. 



