34 Notes on Diatomaceex. Mora Jue EO. 
the obstacle in the shape of the investing membrane is suddenly re- 
moyed. For the motion is the true lively action peculiar to the 
living individual in the naviculiform Diatomacez, and is not in all 
cases towards the opening made, but often many, or, as in some cases 
which have come under my observation, most of the frustules begin 
to move in an opposite direction at first, while at the same time 
many escape by the opening in the tube, and thereafter assume 
vigorous motion in the surrounding liquid. Again, usually some of 
the frustules, being, as at first appears, carried along by the stream 
constituting the mass of those moving towards the opening, all of a 
sudden seem to change their minds, or are struck with an idea, if I 
may so express myself, and here and there will be seen individuals 
which at once alter the direction of their course and move in exactly 
the opposite direction, or backwards as we may say. ‘The individual 
frustules as they escape from the ruptured end of the investing tube 
and enter the surrounding water, do so with the peculiar trembling 
and apparently uncertain movement so characteristic of many of 
these organisms. 
It will be well to note that these observations have been mainly 
made on Schizonema Grevillet, a species occurrmg very commonly 
in New York harbour, although I have noticed the same thing to 
happen with other species of the same genus, and, if I am not mis- 
taken in the allied one, Homcocladia. 
After a time it would seem that the broken end of the tube be- 
comes closed again ; perhaps by the deposition of new matter, or it 
may possibly be by the action of the surrounding water upon the 
fluid within the tube, if it be of a different composition (which would 
seem to be extremely doubtful, however), as the frustules no longer 
attempt to escape, and resume their quiescent state from which they 
have been startled by the accident of the rupture, or they move over 
each other up and down with the same irregularity which is com- 
monly the habit of these forms. 
T am strongly of opinion that certainly in some of the cases in 
which I have seen this escape of frustules take place from the in- 
vesting tube, it has not resulted from any rupture caused by my 
manipulation, but would seem to be a normal occurrence. In fact, 
at such times the diatom is taking upon itself the active or free con- 
dition by means of which the species is to be distributed. And we 
must believe that such is the habit of all so-called epiphytaceous 
forms ; otherwise it is not easy to comprehend how the species 
become so wide spread as many of them are, for we have not at 
present any authentic notice of the formation of free-swimming 
spores in this family. It is hard, when making such observations as 
those I have here recorded, to believe that these organisms are not 
endowed with sentient capacities, especially when one sees, as I have, 
a free frustule of such a Schizonema apparently attempt to regain a 
