296 с. H. Ostf:nfei,d. 



samples from the pack-ice in August 1906 and disappeared together 

 with it when reaching the coastal water, but more slowly (the 

 empty houses are perhaps more persistent than those of var. typica). 

 It was present together with var. typica in Aug.— Sept. 1907 in Dan- 

 marks Havn, but not common, hi 1908 (July— August) it was not 

 present in the coastal water, but appeared in the pack-ice (probably 

 only empty houses) and became common in the samples from the 

 outer margin of and outside the ice. 



Dimensions (in fi) : 325 x 80, 420 X 80. 



D i strib, [oï С. denticiilata): Neritic northern species of wide distribu- 

 tion, known along" tlie coasts from New Foundland north- and eastwards to 

 the Baltic Sea. 



Ptychocylis Brandt, 1886. 



5. Ptychocylis obtusa Brandt, 1896, p. 59, pi. 3, figs. 13, 15; 

 1906—07, p. 310, pi. 57, fig. 8; P. urnula, var. obtusa Jørgensen, 1901, 

 p. 18, pi. 3, fig. 32; P. Drygalskyi Brandt, 1896, p. 59, pi. 3, fig. 14; 

 P. obtusa, var. Drygalskyi Bdt., 1906-07, p. 312, pi. 55, figs. 1-3; pi. 

 56, figs. 3, 4; pi. 57, fig. 10; P. urnula var. digitalis, Jørgensen 1901, 

 p. 17, pi. 2, figs. 29, 30, pl.3, fig. 31; 1905, p. 143. (Fig. 6). 



In samples from Danmarks Havn, Aug.— Septm. 1907, P. obtusa 

 was found in some numbers, but not common; further it was pre- 

 sent in July 1908 in some 

 samples from the coastal 

 water and here not so un- 

 common. It was with some 

 hesitation that I named all 

 the specimens examined 

 P. obtusa, as at least the 

 smaller ones also may be 



named var. Drygalskyi, but 

 Fig. 6. Ptychoculis obtusa Brandt. 250 1. m. . , , . -, , . 



it has been impossible to 



me to find any distinct boundary between the main species and the 



so-called variety. To me it seems, as if var. Drygalskyi is only the 



smaller individuals o£ P. obtusa; and the annexed sketchs will show 



my meaning. Therefore I name them all P. obtusa. 



Distrib. Arctic neritic species known from Davis Strait, Labrador 

 Stream, Norwegian Sea, Norwa\', Spitsbergen. 



6. Ptychocylis urnula (Clap. & Lachm.) Bdt., var. acuta Brandt, 

 1906, p. 28, pi. 56, figs. 1, 2, 6; pi. 57, fig. 7; P. acuta Brandt, 1896, 

 p. 59, pi. 3, fig. 16. • 



In two samples from the outer part of the pack-ice in August 

 1906 a few specimens of a Ptychocylis were observed which I refer 



