N0 - 16 -1 PROTOZOA ON THE ICE-FLOES OF THE NORTH POLAR SEA. 



LACRYMARIA, sp. 

 PI. I, Figs. 1—14; PI. II, Figs. 5-7. 



This infusorium occurred very commonly both in the free-floating lumps 

 of algae, in the channels between the ice-floes, and in the accumulations of 

 diatoms in the ponds on the ice. The individuals were as a rule transparent 

 and colourless, but in some ponds on the ice I also found numerous animals 

 of exactly the same external appearance and shape, but which were dark- 

 green, or almost black. The normal, transparent form will first be described. 

 When it moved actively about, as was generally the case, it had a more 

 or less elongated form (PL I, Figs. 1, 2, 14). The body was very mobile and 

 could be stretched out and become rather slender (Figs. 2 and 14) or it could 

 be shortened and become thicker (Figs. 1 and 3, Fig. 1 is the same indivi- 

 dual as Fig. 2) or it could even be contracted into a spheroidal, motionless 

 globe (Fig. 10). When the body was stretched out, it could bend in a worm- 

 like manner (Fig. 2) and then it could rapidly wind its way between the dia- 

 toms, or could swim freely through the water while its body generally ro- 

 tated slowly round its longitudinal axis. The length of the body of well 

 developed individuals might, under these conditions, be 0-10 mm. (Fig. 1) or 

 more. 



At the anterior end there was a proboscis-like protuberance, which during 

 activity could be pushed out and bent vigorously to the sides whilst, in a 

 more quiescent state when the animal was contracted into a spheroidal form, 

 the proboscis was partly retracted. This proboscis was provided with numerous 

 long cilia, which were in perpetual active motion. Whether these long cilia 

 were actually fixed to the proboscis, or merely situated at its base, surrounding 

 it, was not ascertained. The surface of the body was provided with some- 

 what shorter not very dense cilia. They were somewhat more numerous at 

 the posterior end. 



In most individuals furrows could be seen, winding in left banded spirals 

 along the outside of the body (Figs. 3—7, 13—14). 



As far as I could make out, the spirally wound ribs thus produced, were 

 seven in number (at least on the anterior part) and ended in seven (?) lobes 

 round the proboscis (see Fig. 5, where four of these lobes are seen). These 

 ribs could sometimes also be seen on the posterior end (Fig. 3). 



