4 8 
Classification of Green Algae. 
Agamic reproduction either by division of all the cells 
of the cce.iobium to form as many daughter-ccenobia, or, in 
the highest forms, by similar division of certain reproductive cells 
( partlienogonidia). 
Gamogenetic reproduction known in several genera. In 
the lower it takes place by the division of all the cells of the 
ccenobium into iso- or anisoplanogametes, in the higher by the 
formation ot antherozoids and eggs, which in the highest genus 
are developed respectively from special androgonidia and 
gynogonidia. 
[I'he torms belonging to this group exhibit a strikingly complete and 
wide-ranging progressive series of stages in the evolution of reproductive 
and vegetative characters:—(1) the gradual development of anisogamy 
from isogamy, culminating in perfect oogamy ; (2) a gradual increase in 
the number of cells and a corresponding increase in the size of the 
coenobium, associated in the highest forms with the differentiation of 
purely vegetative from reproductive cells, a differentiation which involves 
the evolution of a true soma or mortal body and the consequent 
appearance of natural death as a regular recurrent phenomenon ] 
Genera. 
^Coenobium of equivalent cells, all capable of reproductive division. 
1. Spondyloinorum. Ehrenberg. 
Ccenobium of sixteen loosely-connected ovoid cells 
arranged in four alternating tiers. No common 
investment. Each cell with a closely adherent wall, 
and four flagella attached to the broad end. Gametes 
unknown. 
2 . Goninm. Muller, 1773 . 
Ccenobium plate-like, of four or sixteen oval or slightly 
polygonal cells connected by protoplasmic processes 
and arranged in one plane, surrounded by a common 
mucilaginous investment. Flagella of all the cells 
on one surface of the plate. Gametes unknown. 
Resting cells (? zygotes) typical. Germination 
indirect. 
3. Tetragonium. West and West. 
Ccenobium as in Gentium, but always of four cells. 
Tips of flagella alone vibratile. 
4 . Stephanosphcera. Cohn, 1852 . 
Coenobium of one to (typically) eight ovoid cells 
arranged in a circle round the equator of the spacious 
spherical or oval investment. Cells with several 
stout radiating protoplasmic processes. Flagella 
penetrating investment equatorially. Isogametes 
spindle-shaped, conjugating within the investment, to 
form zygozoospores. 
(to be continued). 
It. Madley, Printer, Whitfield Street, W. 
