27 



many specimens 



one — 



two — 



some — 



one — 



one 



April 30th, 1897. Rost. Plancton taken in the surface at the 

 quay of Glea. 

 Planorbulina refulgens. d'Orb.. 



— lobatula. Walk & Jacob, 



— coronata, Park A Jones, 



— akneriana, d'Orb., 

 Uvigerina angulosa. Will., 

 Cassidulina laevigata, d"Orb., 

 Globigerina bulloides, d'Orb., 

 Operculina amnionoides, Gronov, 

 Polystouniiella striatopunctata, Park it Jones, two 

 Uvigerina pygmaea, d'Orb.. — 

 Bullimina marginata, d'Orb., 

 Haplophragmium canariense, d'Orb., 



— glomeratnm, Brady, 



Jliliolina seminuluiii, Lin., 

 Nonionina depressula, ^^'alk & Jacob, 



— stelligera. d'Orb., 



Textularia williamsoni. Goes, 

 Pulvinidina concentrica. Park & Jones, — — 



March, .5th, 1897. ()stnes-fiord, Lofoten. Plancton from — 60 m. 

 Planorbulina lobatula. Walk & Jacob, 



— lefulgens, d'Orb., 



— akneriana, d'Orb., 

 Operculina amnionoides, Gronow, 

 Discorbina globularis, d'Orb., 

 Cassidulina laevigata, d'Orl)., 

 Nonionina depressula. Walk & Jacob. 

 Miliolina semigumum, Lin., 



April 28th, LS97, m.. Riist. 



Planorbulina lobatula, 'Walk A Jacob, 



— refulgens, d'Orb.. 



— coronata. Park & Jones, 



— akneiiana, d'Orb., 

 Uvigerina pygmaea, d'Orl)., 



— angulosa, \\'ill., 



Polyuiorphina compressa. d'Orb., 

 Cassidulina laevigata, d'Orb., 

 Globigerina bulloides, d'Orb., 

 Nonionina depressula. Walk & Jacob, 

 Haiilophragmium nanum, Brady, 

 Pulvinulina concentrica. Park it Jones, 

 Discorbina obtusa, d'Orb.. 

 Laatena lucida. Will. var. nordgaardi, n. v. 



two — 



Description of the new var. 



Pyriforniis aut ovalis, vix compressa, obtuse mar- 

 ginata, utrinque costa lata praedita, en tos ol er nica, 

 apertura ovalis magna. Long. 0..33 ram. 



This nice form is pear-shaped or oval, and scarcely compressed 

 from the sides, the keel is obtuse and has on either side a parallel- 

 running, thickened stripe, which ends above in a I'ounded point at 

 a distance of about one thiixl of the length of the shell from the 

 mouth-opening; below it is somewhat bent upwards and somewhat 

 narrowed by the button-shaped thickening that the shell ends in. 

 This stripe is by transparent light dai-k. by surface light it is 

 white, the elevation of it being (piite small. At the mouth the 

 shell is squarely cut off, at the lower end it is drawn out into an 

 obtuse prolongation. The species reminds one very much of I. 

 quadricostata, Reuss, but is distinguished from the latter species by 

 the form of the stripes, the almost Indl-shaped shell, and by the 

 oblong aperture, which is pointed to both sides. 



Two specimens were found liy Mr. 0. NoitDGAARD at Riist in 

 Lofoten, and were called after him". 



two — 



some 



many specimens 



two 



one — 



some — 



two — 



one — 



many specimens 



two — 



some — 



one 

 some 



two 

 one 



At the present stage of my investigations of animal plancton 

 at our coasts, it is impossible to give any general description. 

 What has till now been done in this held must rather be said to 

 be of a reconnoitering kind. I have tried to obtain knowledge of 

 the forms, their horizontal and vertical distribution, but have till 

 now undertaken no quantitative plancton determinations. Of course, 

 I have seen that there is great difference in the quantity of animal 

 plancton in the months of September and February, for instance. 

 In Lofoten it is rather poor in the latter month, especially in the 

 surface strata, as is also the case in the fjords near Bergen. Both 

 animal and vegetable plancton, however, is found also in the month 

 of F(;bruary. Arctic copepods, as mctridia longa, eiirhosta norvegica, 

 and calaniis In/perboreus, I have scarcely ever taken in tlie surface 

 strata (0 — 50 m.). But in the deep, where the temperature has 

 been about 6" C, and the saltness 34—35 "/oo, m. longa and c. 

 hyperhorms have occurred in greater numl)ers, especially in Lofoten. 

 Near Bergen too, I have observed a few specimens of the above- 

 mentioned arctic copepods. Recently there occun'cd further a 

 female f)f lietiTocliceta iwrvegicft (By-fjord, Aug. 24th, 1897, 0—300 

 m.). The occurrence of arctic cojjepods in our waters can scarcely 

 be used to support the so called "current hyjiothesis''. It is likely 

 that dr. H.toet is right in saying that these animals occur in the 

 deep of the fjords because arctic conditions are prevailing there. 



Through a seal-hunter at Troniso I have obtained some 

 plancton samples from the sea between Norway and Spitsbergen, 

 taken in the summer season. In some of these occur great 

 numbers of calanns hyperhoreus from the surface stiata. At our 

 coast, however, I have, as mentioned above, hitheito only taken 

 this species in somewhat deeper water. AVhat appears particularly 

 characteristic of arctic conditions, is the great uniformity throughout 

 the year of temperature and saltness, and it is therefore likely 

 that the arctic animal forms occurring in our waters keep in the 

 deep, because the physical conditions there are most corresiiondinff 

 to those of the Arctic Ocean. 



I thus think I jiave observed, in the case of several arctic 

 copepods. that in our waters they arc chiefly bound to the deep, 

 and this circumstance may be one of the conditions tiiat cause their 



