FUNDAMENTAL FORMS. 333 
nation, and is as perfectly simple in its structure as any 
crystal, which consists of a single inorganic combination, 
for example, of a metallic salt or of a silicate of the earths 
and alkalies. 
As naturalists believed in differences in the inner struc- 
ture or composition, so they supposed themselves able to 
find complete differences in the external forms of organisms 
and anorgana, especially in the mathematically determinable 
crystalline forms of the latter. Certainly crystallization 
is pre-eminently a quality of the so-called anorgana. 
Crystals are limited by plane surfaces, which meet in 
straight lines and at certain measurable angles. Animal 
and vegetable forms, on the contrary, seem at first sight to 
admit of no such geometrical determination. - They are for 
the most part limited by curved surfaces and crooked lines, 
which meet at variable angles. But in recent times we 
have become acquainted, among Radiolaria * and among 
many other Protista, with a large number of lower 
organisms, whose body, in the same way as crystals, may be 
traced to a mathematically determinable fundamental form, 
and whose form in its whole, as well as in its parts, is 
bounded by definite geometrically determinable planes and 
angles. In my general doctrine of Fundamental Forms, or 
Promorphology, I have given detailed proofs of this, and at 
the same time established a general system of forms, the ideal 
stereometrical type-forms, which explain the real forms of 
inorganic crystals, as well as of organic individuals (Gen. 
Morph. i. 375-574). Moreover, there are also perfectly 
amorphous organisms, like the Monera, Amceba, ete., which 
change their forms every moment, and in which we are as 
little able to point out a definite fundamental form as in 
