THE PRINCIPLES OF BIOLOGY. 
333 
THE PRINCIPLES OF BIOLOGY. 
BY HERBERT SPENCER. 
Exposition of Chapter XII. — On “ Distribution.” 
BY WILLIAM MATHEWS, M.A., F.G.S. 
In studying the distribution, on the earth’s surface, of 
any group of organisms, two facts, of widely different signi¬ 
ficance, are presented to our attention. First, the character 
of the inhabitants of any given locality depends upon the 
nature of the locality ; secondly, two localities approximately 
similar in nature will, if sufficiently far apart, be tenanted by 
different collections of organisms; the species inhabiting them 
will, as a general rule, be representative and not identical. 
In the remarks which I am about to offer on the subject 
of distribution, I propose to examine briefly some of the 
leading phenomena presented by the distribution in space of 
flowering plants. 
The habitats of such plants are characterised by one or 
more of the following variations and conditions : — 
(A.)—Differences of land and water— 
Marine. 
Fresh water. 
Stagnant. 
Running. 
Marsh. 
Land. 
Littoral. 
Inland. 
(B.)—Differences of soil— 
Calcareous. 
Argillaceous. 
Siliceous. 
(C.)—Differences with respect to cultivation or otherwise— 
Meadows, Pratal. 
Pastures, Pascual. 
Arable land, Agrestal. 
Heaths, Ericetal. 
Road sides, Viatical. 
Hedges, Septal. 
Woods, Sylvestral. 
Rocks, Rupestral, 
