V -THE FOOD OF MARINE ANIMALS. 



By Prof. K. Mobius. 



[From " Tugeblalt der 53. Versammlung Deutscher Naturforscher nnd Aerzte in Danzig, 

 1880." Journal of the 53d Conference of German Scientists and Physicians, held at 

 Danzig, 1880. No. 6, September 22, 1880.] 



All the known forms of animals may be divided into 155 orders ; of 

 these 52 live on land, 67 in fresh water, and 107 in salt water. The sea, 

 therefore, is richer in animal forms than the fresh water and the land, 

 and also produces more individuals than fresh water and laud combined. 



As the number of domestic animals on a farm depends on the extent 

 and quality of the land belonging to it, in the same way the number of 

 animals in the different domains of nature, both on land and iu water, 

 depends on the quantity of food. 



As no animal is able to form the organic combinations of its body 

 direct from water, air, and mineral substances, all animals of our earth 

 depend on the quantity of organic matter produced by the vegetable 

 kingdom ; and the number of animals inhabiting the different seas, there- 

 fore, likewise depends on the quantity of organic nutritive matter which 

 the water, either directly or indirectly, receives from the vegetable king- 

 dom. 



To prove this let us first of all cast a glance at our own seas, the 

 Baltic and the North Sea. 



Large meadows of green sea- weeds extend in the shallow waters near 

 the coast, wherever the bottom does not consist of shifting sand, in 

 which no plant can take root. Wherever the bottom is stony, brown 

 algas (fucoids) grow, and further away from the coast, at depths of GO to 

 80 feet, the bottom is in many places covered with red algae (florids). 

 At a still greater depth there are few or no plants ; but aquatic plants 

 torn loose from the places where they grew are often brought up in 

 dredges from a depth of several hundred yards. After the gases filling 

 their tissues have escaped, such plants sink towards the bottom, fall to 

 pieces, and finally form the principal component part of the mass of 

 dark, soft mud forming the bottom of many bays of the Baltic and 

 North Sea. When such mud, brought up in dredges, is put into a barrel, 



* DU> Nahrung der Seetiere. Vortrag von K. Mobius, Professor in Kiel. Translated by 



Herman Jacobson. 



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