262 a. wadlucal and d Physiological Bienen aes ge 
Aachciie de 
the cell-wall at all but two points, where it protrudes ‘itatiph Fae 
the wall in the form of long vibratile cilia, by the motion of . 
‘which it is propelled through the water. The cilia are ex- ‘a 
tremely delicate, and are invisible except when moving very 
slowly, or when artificially coloured by some reagent, as — 
iodine, which, however, kills the plant. In this condition it - | 
sometimes loses its cell-wall, and swims about as a naked 
primordial cell. Eventually, however, it loses its cilia, 
clothes itself with a coat of cellulose, and becomes quiescent. 
In this state it may retain its vitality when dried up, even 
for years ; and will then resume its activity when again placed 
in water.—ED. | 
Crass, IL. Fier: 
The elements of which the vegetative parts of Fungi 
that do not subserve the process of reproduction, consist, — 
are hyphe, or filaments of cells destitute of chlorophyll, 
which usually branch repeatedly by lateral ramification, and 
grow only at their apices. Ina small group which forms a 
transitional step from Algz to Fungi, the Phycomycetes, 
the entire vegetative portion of the Fungus consists of 
a single undivided cell. The next group in the ascending 
series, the Mould-fungi, consists only of a single often much 
branched filament of cells. Even in the highest forms the 
filaments either run parallel to one another, or in an irre- 
gularly complicated mass, but often forming structures of an 
externally definite form characteristic of particular species. 
Sometimes the hyphz are compacted at particular parts into 
a dense parenchymatous structure, known as a pseudo-paren- 
chyma, as on the surface of the larger Fungi, where it forms 
their skin. | leo Se 
A number of unicellular organisms, such as, especially, ) 
the Yeast-fungz, which form cloudy or slimy precipitates or 
pellicles on the surface of organic. bodies in a state of de- 
composition, are also usually included in this class, It is, | 
‘however, still doubtful whether these organisms are only — ae 
