294 с. H. Ostenfeld. 



largest one (placed most at right). It we compare the specimens 

 with the figures quoted above from Jorgensen's and Brandt's papers, 

 we shall find a close resemblance. The smaller specimens answer 

 to Jorgensen's f. acuta (1901, p. 12), the larger ones to his f. caudata 

 (1901. p. 12), but 1 have not succeeded in finding any definite limit 

 between them. 



All the specimens which I reckon to the var. typica have in 

 common : long and well-developed teeth in the mouth of the house, 

 the lower end not sharply set off from the main part, but of vari- 

 able length and often forming a distinct "Fortsatz"; the structure of 

 the house-wall is not coarse. 



Var. typica was dominant in the samples from the pack-ice in 

 August 1906, but not present in the coastal water. It was found 

 sparingly in the samples from Danmarks Havn in October 1906 

 (under the ice), but mostly only empty houses. In 1907 it was 

 dominant in Danmarks Havn in Aug. — September. In July— Au- 

 gust 1908 it occurred sparingly in the samples from the coastal 

 water, while dominant in those from the pack-ice and again rare 

 outside this, when the temp, rose from 0° — 2'' С to 6° — 7°. In the 

 last region where 1 found it with resting spores (cfr. Laackmann, 

 Wiss. Meeresunters., Abt. Kiel, 1906), the specimens were small and 

 approached the oceanic species С edentata Bdt. (f. parumdentata Bdt.). 



The dimensions of the houses of some of the measured speci- 

 mens follow here : 



b. var. gigantea (Bdt.) Jørgensen, 1899, p. 35, pi. 3, figs. 26-28; 

 1901, p. 14; Brandt, 1906—07, p. 233, pi. 38, figs. 2,3,8,9; C. gigantea 

 Brandt, 1896, p. 63, pi. 3, figs. 21—24; Ostenfeld, 1. с, 1899, p. 62. 

 (Fig. 4). 



In the samples from Danmarks Havn, Sept. 1907, I found together 

 with the preceding form a still larger one, which agrees well with 

 var. gigantea. It dilfered from var. typica in its greater length and 

 the short teeth in the mouth of the house ; the structure of the 

 house-wall was the same. 



Besides in the two mentioned samples, it was found very spar- 

 ingly in July 1908 in and olf Danmarks Havn (two samples) and in 

 the pack-ice (two samples). It was not always easy to distinguish 

 it from var, typica. 



