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Professor Mohs’s General Reflections on 
to it by rivers, like the salt lakes of Persia and Siberia. The 
want of contractile power in this zoophyte, and the absence of 
all organs for seizing prey, show that it is nourished only by the 
particles of organic matter suspended in water, or by the ele- 
ments of that fluid, which is further indicated by the constant 
streams through its body, and by the development of its ova, 
when supported only with rain water. The great looseness and 
softness of its texture, and the width and defenceless condition 
of its openings, which now render the spongilla a safe retreat, 
and a convenient magazine of food for myriads of animalcules 
and aquatic insects, and a fit receptacle for their ova, obscurely 
indicate the unpeopled state of the waters of the globe, and 
consequent absence of these numerous assailants, at the period 
of the first formation of this zoophyte ; and its aptness for secre- 
ting silica, and the abundance of that earth in its skeleton, show 
the period of its creation to have been nearly synchronous with 
that of the siliceous or primitive rocks. 
Art. IX. — General Reflections on various important subjects 
in Mineralogy. By Frederick Mohs, Esq., Knight of 
the Order of Civil Merit, Professor of Mineralogy at Frey- 
berg, Fellow of the Royal Society of Edinburgh, of the 
Wernerian Natural Society, &c. (Concluded from p. 28.) 
HI HE natural-historical resemblance of several species consists 
in their greater or less agreement in regard to their natural- 
historical properties. In order to find out this agreement, we 
must consider the species as wholes (which they are, according 
to the general idea developed above), and not in single varieties, 
but as complete as possible ; in the same manner in which the 
botanist and zoologist have to compare the complete species of 
plants and animals, before they can judge rightly of the genus. 
Thus, a representation is produced, in which all the single con- 
nexions of certain natural-historical properties to be met with in 
individuals in some respect disappear, and are melted together 
into a kind of mean ratios. This original representation of the 
species, as it may be called, is different from the idea of the spe- 
cies, which only shews what the species are, and also different 
