MICROSCOPY. 875 
3. In the Saprolegniei there is but one kind of sporangia ; 
those which develop parthenogenetically, and those which are fer- 
tilized are identical, and show no difference originally. The un- 
fertilized zoospores grow sooner and more readily than those 
which are fertilized. 
4. Several peculiarities in the formation of zoospores, which 
have been considered sufficient specific distinctions, are not import- 
ant as such, but are merely evidences of a greater or less tendency 
to dimorphism, representing various stages of development in the 
zoospores. 
5. Also various sexual forms of growth may appear in the 
same species, which are not reliable as specific distinctions.— 
S. 
Section CUTTERS. — At the Queckett Club, Mr. T. C. White al- 
luded to the impracticable expensiveness of many excellent sec- 
tion cutters, and stated that he had used with great success @ 
contrivance, which consisted of a brass tube fastened at right angles 
with a brass plate, upon which a glass plate with a corresponding 
aperture was cemented for a cutting surface. The substance to 
be cut was embedded in an inner tube which was simply pressed 
up by the finger when required. 
Mr. Walter White read a paper on the “ Science-Gossip” section 
cutter in which the plug holding the object is raised by slight blows 
upon a wedge, instead of by a screw. 
The President, Dr. R. Braithwaite, said that he did not possess 
a section machine, but was accustomed to cut sections of sphag- 
num and other leaves by inserting them in a slip of soft cork and 
cutting them by hand. 
LecTurE-ILLUsTRATIONS OF Microscopic Oxnsects.— Rev. W. H. 
Dallinger has communicated to the Royal Microscopical Society 
an improved method of preparing transparencies for use with the 
lime-light and lantern. He finds large drawings unsatisfactory 
for a large audience, as well as incomplete in detail, unless pre- 
pared with great labor and skill, and the usual transparencies for 
screen use, whether photographed or painted, cost too much time 
and labor to be always available. To obviate these difficulties, he 
draws the magnified image on a surface of finely ground glass of 
the size of a magic-lantern slide. , The drawing is as easily done 
as upon card, using a black lead pencil, and the camera lucida if 
