NOTES AND QUERIES. 143 
The advantages to Microscopists of this Trough over every other 
hitherto introduced must be at once apparent. By adding a little 
water (by means of a pipette) every day or two, to supply the loss 
Fig. 22. 
caused by evaporation, minute forms of Infusoria can be watched 
for weeks and their development traced. For the larger forms of 
pond life this Trough is no less useful—Melicerta, Floscularia, &c., 
&c., living in it for weeks without removal. Microscopists are thus 
able, by keeping a few Troughs in use, to place a variety of living 
specimens at once under the Microscope without trouble or loss 
of time. 
MovVEMENTS OF D1aToms.—At a recent meeting of the Royal 
Microscopical Society, a communication was referred to, on the 
movements of diatoms, in which the views of M. Mereschkowsky 
were controverted. 
The President said if they wanted to see diatoms to the best ad- 
vantage, they must see them under natural circumstances, If they 
were put upon a slide with a glass cover over them, the water 
became chilled, and their movements were to a great extent 
stopped ; but if the slide was warmed, their activity was increased 
to a much greater degree than usual. Under proper conditions, 
with a 1-16th immersion objective, he had distinctly seen the wavy 
movement of the protoplasm, but the impression was strong upon 
his mind that there was something else concerned in the movement 
in addition to this. It struck him that some of the movement was 
produced by the action of heat-currents in the water, for the things 
were so light as to be most easily influenced in that way; from 
his own observations he must consider it to be due to more than 
one agency. 
THE CLorH Motu.—Zinea fapetzella is one of those Tineide 
which sometimes do a great deal of mischief in houses. The 
larva constructs for itself a protecting tube from the fibres and 
small pieces of the stuff it delights to gnaw. After a time the 
caterpillar closes one end of its tube and attaches it to some fixed 
body; it then becomes metamorphosed, the chrysalis eventually 
