20 FRIDTJOF NANSEN. [norw. pol. exp. 



on the under side of the body; but I had not seen it. At the same 

 time the first vacuole (situated on the upper side of the body, nearest the 

 eye) was considerably reduced. The contractions of the vacuoles occurred 

 curred at long intervals. The tentacula were slender, straight, apparently 

 rigid, and ending in a slight knob. I did not sec them move, but there was 

 occasionally a slight vibration in them. 



The interior of the body was filled with big refractive globules (Fig. 3, b) 

 which may be reserve nourishment. They do not approach close to the sur- 

 face. In the outer layer a great mumber of small grains occur (Fig. 3, a) 

 which have a rapid, half oscillating movement, while swimming about. What 

 I assumed to be the nucleus, was situated near the upper side of the body, 

 and there were i Fig. 2 no refractive globules but only small oscillating grains 

 between it and the outer membrane or surface. It appeared as an oblong 

 granular mass. The granular appearance might have been due to threads. 



The colour of the organism was slightly yellowish green, which seemed 

 to be due to the refractive globules (Fig. 3, b). 



Length of individual about 0095 mm. 



I kept this organism under observation during the whole day (July 30) 

 till interrupted by a bear in the evening. 



When I came back after a few hours, the water had been much reduced 

 by evaporation, and the organism had become much contracted on the one 

 side. When fresh water was added it again expanded, and then I left it for 

 the night. 



The next morning, July 31, 1894, it had about the same appearance, but 

 was slightly contracted, and somewhat reduced in size. Later on in the day, 

 while I was following the developement of the organism illustrated on Pis. V — VI 

 which was in the same preparation, the cover-glass was several times touched 

 by the microscope, and great masses of the cell contents were twice squeezed 

 out. The first time the organism was much contracted and of irregular shape 

 (like Fig. 1) but after a while it returned to its regular, spheroidal form. After 

 the second time I could observe no motion in the organism. The big glo- 

 bules (Fig. 3, b) which had been spueezed out into the surrounding water ap- 

 peared at first to have a nearly homogeneous structure, but the contents 

 of rome began in the evening to be differentiated into one or two "nuclei" 

 and a granular mass (PI. VI. Fig. 20, c). Some of them also began to 



