THE ZYGNEMACE.E. 
321 
of these latter from an accidentally ruptured cell: their 
motion was very feeble and not at all like to the same bodies 
normally produced in other algas. 
There is no more deeply moving and exciting spectacle in 
the whole range of natural phenomena than is afforded in 
witnessing the emission from the mother cell of normally 
produced zoogonidia, as it occurs in the genus Ulothrir . You 
perceive that the cells of certain filaments are densely packed 
with green ovoid granules, in place of the usual quadrangular 
plate of endoebrome: you are gazing upon these apparently 
inert masses of matter, when lo ! in an instant, and without 
premonitory symptom, the entire mass of granules in a cell is 
in motion, and a portion is seen protruding through the cell- 
wall ; in a short space, and by successive efforts, flic entire 
mass passes out of the cell, which closes with a rebound. It 
is then seen that these bodies are enclosed in a filmy envelope 
of bubble-like tenuity. After a brief period of repose, the 
outer members of the group begin to jerk and tug and oscillate, 
and soon separate themselves from their fellows ; the 
remainder speedily follow, and you have before you a group 
of from 8 to 32 or more biciliated subpyriform bodies all in a 
state of wild activity. Cell after cell rapidly discharges its 
contents till you behold a mass of bodies madly gyrating and 
waltzing round each other as if, by this, giving expression to 
their sense of this new active and exuberant life. On viewing 
the empty cell there is no apparent rupturing of its wall; it is, 
therefore, presumable that the escape of the body of micro- 
zoogonida is effected through an orifice specially formed in the 
cell-wall at the precise period required for its emission : and 
this is precisely analogous to what takes place at the period of 
the fertilization of the oosplieresin Vaucheria and OZdoyonium . 
Pre-eminent among the many questions of importance at 
present engaging the attention of vegetable physiologists are 
the nature of the relations that exist between the cell-wall 
and the protoplasm, and the possible continuity of the 
protoplasm through the walls of cells. Until recently the 
cell-wall has been regarded as a sort of protective envelope, 
elaborated by the protoplasm body, and in which it, in a 
manner, imprisoned itself and cut itself off from contact or 
connection with the protoplasm of neighbouring cells, a wall 
which acts, as Professor Hillliouse has said, towards the 
individual cell as an exoskeleton. Facts are now rapidly 
accumulating which will no doubt ultimately lead to an 
abandonment of that conception. As Hillliouse observes, “ in 
modern teaching the vegetable organism is a whole, with its 
protoplasmic body, it is true, broken into fragments which 
