ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
411 
which appear to have no contractile property. The growing point and 
the whole corm are constantly forced downwards by the growth of the 
new buds which are formed on its upper surface. 
Germination of Cryptocoryne.* — Prof. K. Goebel describes the 
structure of Cryptocoryne spiralis and ciliata , marsh plants, species of 
Aroideae, in which the embryo germinates while still attached to the 
plant. The small spadix is completely hidden within the spathe; an 
outgrowth from the spathe above the spadix prevents the access of larger 
animals, while small insects enter freely, and effect the carriage of the 
pollen to the stigma. The ovules are characterised by the very strong 
development of the outer integument. When the embryo begins to ger- 
minate, the cotyledon serves as an absorptive organ, and after the endo- 
sperm has been consumed, the embryo derives the greater part of its 
nutriment from the outer integument of the ovule. 
Phenomena of Symbiosis.f — Mr. A. Schneider classifies the phe- 
nomena of symbiosis under the following heads : — 
I. Incipient Symbiosis (Indifferent Symbiosis). 
1. Accidental Symbiosis. 
2. Contingent Symbiosis. 
II. Antagonistic Symbiosis. 
1. Mutual Antagonistic Symbiosis (Mutual Parasitism). 
2. Antagonistic Symbiosis (Parasitism). 
a. Obligative Antagonistic Symbiosis. 
b. Facultative Antagonistic Symbiosis. 
3. Saprophytism. 
a. Facultative Saprophytism. 
b. Obligative Saprophytism. 
III. Mutualistic Symbiosis. 
1. Nutricism (Semi-mutualistic Symbiosis). 
2. Mutualism. 
3. Individualism. 
a. Semi-individualism. 
b. Complete Individualism. 
IV. Compound Symbiosis. 
Accidental symbiosis represents the least specialised form, and is of 
wider occurrence than all the others combined. Contingent symbiosis 
( Raumparasitismus ) involves a preference displayed by one organism 
for living in contact with another. Nutricism is illustrated in myco- 
rhiza, such as that of the roots of Cupuliferte ; mutualism in the root- 
tubercles of the Leguminosse. The two forms of individualism occur 
in the lower and the higher forms of lichens. Compound symbiosis 
is found especially in the animal kingdom. 
Effect of Mineral Salts on Development.! — M. C. Dassonville has 
experimented on the effect of solutions of mineral salts (chiefly Knop’s 
solution) on the growth of different grasses (wheat, rye, oat, maize, &c.) 
as compared with that of pure water. He finds the general result to 
* Flora, lxxxiii. (1897) pp. 426-35 (12 figs.), 
f Minnesota Bot. Studies, 1897, pp. 923-48. 
t Comptes Rendus, cxxiv. (1897) pp. 1467-70. 
