TRANSACTIONS. 
On some Diatomacej^ that are found in Noctiluca miliaris, 
and the best means of obtaining them. By Colonel W. H. 
C. Baddeley. Communicated by Mr. F. C. S. Boper, 
F.L.S., &c. 
(Read April 20tl., 1858.) 
While engaged in endeavouring to ascertain the mode of 
reproduction in Noctiluca miliaris, I remarked in all fresh 
specimens of this creature a mass of dark matter near the 
nucleus^ and on a closer examination found it consisted chiefly 
of Diatomacese. This has before been casually noticed by 
Mr. Brightwell and others ; it is therefore mainly for the pur- 
pose of inducing others along the coast to examine these crea- 
tures for the sake of the Diatoms they contain^ that I send 
the method I employ to capture them^ and some of its results. 
The Diatoms lie in the so-called vacuoles^ which the 
creature appears to have the power of moving by means of 
the threads to which they are attached. By this arrange- 
ment the vacuoles are brought towards the apparently slit- 
like opening of the mouth to receive the food^ and are after- 
wards drawn back again into various portions of the body. 
Having ascertained of what this food consisted^ it occurred 
to me that here was an easy method of obtaining different 
marine species of Diatoms^ and I at once tried to ascertain 
the best means of securing a good supply of these interesting 
little animals. I adopt the following plan : 
Attach a fine muslin net to the end of a light pole^ and pro- 
ceed to some spot where the Noctilucse are likely to be driven. 
A breakwater which causes an eddy to collect Medusae^ &c., 
generally yields a good harvest. 
Skim the surface, and wash the net repeatedly in a can of 
salt water; at night, these creatures are easily seen by their 
luminosity; by day, if plentiful, they cover the surface of 
the sea in brownish streaks. 
Having secured what is required, return home, and pour 
the water into a white hand-basin, allowing it to stand an 
hour or two. This rough treatment causes these creatures 
to disgorge their food, and if, after an interval, the water be 
carefully poured off, a sediment will be found at the bottom y 
which will consist of Diatoms mixed with some refuse. 
VOL. VI. i 
