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Classification of Green Algce . 
Fam. II. Tetrasporaceae. 
Plant-bodv rarely unicellular never motile when adult though some¬ 
times ciliate, usually consisting of the products of successive vegetative 
divisions united by the more or less mucilaginous remains of the 
mother-cell walls to form a colony , often of fairly definite form. Cells 
always rounded or oval and mostly showing the chlamydomonad-type 
of organisation, usually lacking however, the eye-spot. Reproduction 
typically by zoospores arising lrom any of the cells of the body 
and often also by conjugation of isoplanogametes. 
*Ciliatae. 
Individual cells generally provided with two flagella, but the 
whole colony immotile. 
[The flagella found in this group are usually extremely long, being 
mostly imbedded in the mucilaginous matrix of the colony. They appear 
to be functionless and have indeed been often overlooked. Only in 
Physocytium , the simplest member of this group, have they the chlamjdo- 
monadine appearance and this apparently indicates the phylogenetic 
origin of the group.] 
• 
Genera. 
1. /’hysocytium. Borzi. 
Colony globular, attached by two fine threads which 
seem to be derived from the flagella of a zoospore 
which has anchored itself by means of them. The 
cells within the colony, few in number, and irregularly 
clustered, arise by division of this zoospore body; 
each cell has usually two short flagella. Isogametes. 
i 
2. Apiocystis. Nageli. 
Colony pyriform, firmly attached by the narrow end; 
interior of very thin mucilage. The cells are distri¬ 
buted in a single layer below the surface, and each 
may or may not have two long cilia. Zoopores and 
gametes known. 
3. Tctraspora. Link. 
Colony a floating crumpled membrame of indefinite 
form. Cells bifiagellate distributed in a single layer 
and grouped in fours. 
[The long flagella of the cells are obvious in the very young colonies, 
but not easily detected in tbe thick mucilage of the old ones. Thuret 
figured the flagella in 1850 (Ann. Sci. Nat., Bot., ser. 3. tom. xiv, pi, 21, 
fig. 7) but several subsequent writers have ignored them.] 
4. Stapfia. Chodat, 1897. 
Colony vermiform of dense mucilage cells in a single 
layer below the surface. Flagella conspicuous, but 
entirely imbedded in the mucilage. 
** Dendroidcce . 
Colonies consisting of oval cells grouped to form more or less 
tree-like clusters by the united but not confluent remains of 
the mother-cell walls. 
