209 



shown in the Plankton-tables given above, in which is recorded: — 

 (1) The number of the samples; (2) the habitat; (3) the tempera- 

 ture of the water; (4) its salinity; (5) its colour (Forel's scale); 

 (6) the times for the collecting (day, month and hour); (7) the 

 Protophytes and Protozoes contained in the sample — the scale of 

 frequency used being the usual subjective one: — CC denoting 

 dominant; С very common; 4- rather common; г rare; and rr 

 singly (only a few or a solitary individual observed). The rare 

 organisms are not recorded in the tables, but in a separate list 

 (pp. 170 — 174); in the list (pp. 159 — 169) where all the organisms 

 are enumerated, they are marked by an asterisk. 



Voyage out. The North Sea contains Triposplankton (p. 147). 

 Around Fair Isle oceanic forms (Peridinium ovatum, P. pallidum, 

 Rhizosolenia semispina) occur mixed with neritic ones. — The 

 Plankton of the North Atlantic (from Long. 4° W.) contains every- 

 where Coccolithophora pelagica, but is otherwise variable (pp. 

 147 — 148); at Long. .15° — 31° it is characterized by containing 

 Thalassiothrix Frauenfeldii; at Long. 31° — 36° by Chœtoceras 

 peruvianum, etc.; while the Polar Current off the east coast of 

 Greenland is filled with Trichoplankton {Thalassiothrix longissima ; 

 Coscinodiscus marginatus; Rhijnchomonas marina) and strangely 

 enough Rhizosolenia stylifoi'mis, which is otherwise a warm water 

 form. Homewa^rd route. Around Gape Farewell occurred a 

 curious , partly Icelandic-neritic , partly eastern-oceanic Plankton 

 (p. 150) which may be explained by the fact that water from the 

 east part of the North Atlantic Ocean, containing oceanic forms, 

 has during the summer months flowed on towards the north-west 

 till it has touched the south coast of Iceland, whence it has taken 

 along with it some neritic forms and has then gone on along the 

 coast westward to Irminger Sea where a part of the water in 

 question has been carried along by and mixed up with the Polar 

 Gurrent from off the east coast of Greenland, from whence also 

 some forms occur. A similar circulation of water is mentioned and 

 figured by Ryder (I.e.). — The warm part of the route in the 

 Atlantic Ocean contains variations of Scoticaplankton (p. 152), 



As Dr. Steenstrup's apparatus works continually and gives pure 

 samples , these gatherings are useful to control and to compare 

 with the usual collections made on the routes to Iceland and 

 Greenland which have hitherto been investigated by Ostenfeld 

 (v. pp. 144 — 145). A comparison shows (1) that it is sufficient 

 XXVI. 14 



