ARTIFICIAL OYSTER CULTURE. 1059 



animals of three different species Very few 



p]ants grow upon the banks. Upon only a single one of 

 the oyster-beds of the sea-flats has eel-grass (Zoslera 

 marina] taken root, (c] Upon other beds reddish-brown 

 algae (Floridiae] are found, and, floating in the water which 

 flows over the beds, occur microscopic algae (Desmidiae 

 and Diatomaceae], which serve as nourishment to the 

 oysters. If the dredge is thrown out and dragged over the 

 sea-flats between the oyster-beds, fewer and also different 

 animals will be found upon this muddy bottom than upon 

 the sand. Every oyster-bed is thus, to a certain degree, 

 a community of living beings, a collection of species, and a 

 massing of individuals, which find here everything neces- 

 sary for their growth and continuance, such as suitable 

 soil, sufficient food, the requisite percentage of salt, and a 

 te'mperature favourable to their development. Each species 

 which lives here is represented by the greatest number of 

 individuals which can grow to maturity, subject to the 

 conditions which surround them, for among all species the 

 number of individuals which arrive at maturity at each 

 breeding period is much smaller than the number of germs 

 produced at that time. 



Science possesses, as yet, no word by which 

 such a community of living beings may be designated ; no 

 word for a community where the sum of species and indi- 

 viduals, being mutually limited and selected under the 

 average external conditions of life, have, by means of 

 transmission, continued in possession of a certain definite 

 territory. I propose the word Biocoenosis (d\ for such a 



(c) This weed grows in great quantities on the French beds, and 

 proves very useful in protecting the oysters at low tide from the heat of 

 the sun. 



(d) From Bios, life, and komoein, to have something in common. 



II 2 



