146 
becomes poorer, evidently on account both of the high temperature 
to which the water becomes heated, and of the scarcity of food. 
Also the raised salinity, of course, must be unfavourable to organic 
life; in the small pools with the crystallized salt no trace of 
organic life was found at all. 
In some of these pools out of the constant reach of the waves 
I found aåa curious organism growing on the bottom. It was å 
rather consistent mass of a very light brownish or yellow colour 
and looked most like a kind of sponge. The largest specimen seen 
was about the size of a knotted hand. Some specimens were 
preserved in alcohol. On my return to Copenhagen I asked Mr. W. 
Lundbeck, the eminent author of the Porifera of the Danish 
«Ingolf”-Expedition to examine them. He at once came to the 
result that the organism had nothing to do with the Porifera; it 
was a jellylike mass full of fine threads, which seemed to be of 
plant origin. I then asked Mag. Raunkiær and Dr. L. Kolderup 
Rosenvinge to examine the organism, and both came to the 
result that it was a colony of Thread-Bacteria. Especially Dr. 
Kolderup Rosenvinge examined it more closely and sent me 
the following description. 
«The firm jellylike mass, which is stated to have been yellowish 
or slightly brownish coloured in life, is formed by a thin, thread- 
like organism, which, on assumption of the cells having been 
colourless, must be referred to the Thread-Bacteria (CA/amydo- 
bacteriaceæ). The threads consist of rodshaped cells, ca. 14 thick 
and ca, 2—4 times so long, and are provided with a thin sheath, 
which colours strongly in hæmalum. The threads lie mainly parallel 
and appear møstly unbranched, false ramification, however, occurs 
now and then; they are imbedded in a homogeneous jelly, but free 
threads project above the surface of the jelly. On and in the jelly 
different Algæ occur, especially a Lyngbya, which are partly imbedded 
in the jelly, partly freely projecting; further, juvenile stages of å 
Cladophora and some few other Algæ. 
Whether the colour of the jelly in life originates from the 
