WOODWARD, ON MONOCHROMATIC ILLUMINATION. 253 
Cothurnia maritima. It is the lorica which alone diverges 
from the usual type, and which is, as shown by the drawing, 
longer, narrower at the upper part, and deeply notched on 
either side, in one or other of which the animal rests when 
extended. 
The range of infusorial variability is at present but little 
defined—its extent, perhaps, scarcely suspected by micro- 
scopists; we are, therefore, but too much disposed to confer 
names upon and create species out of mere varieties. The 
Cothurnia maritima I figure, however, is certainly so re- 
markable a variety that I think it may legitimately enough 
be named Corthunia maritima, var. incisa. 
The visitor to Hastings and St. Leonards will find the 
ditch J refer to, more particularly the broad end of it furthest 
from St. Leonards, a productive locality. Not only can a 
good gathering of Diatoms be obtained from it, such as 
Pleurosigma elongatum, P. angulatum, P. balticum, Amphi- 
prora alata, Achnanthes brevipes,Surrirella striatula,Epithemia 
constricta, &c., but it abounds in many interesting forms of 
infusorial life—amongst them, Tintinnus Cothurnia, a Baltic 
species (which I now, I believe, for the first time record as 
British also), Vorticella convallaria, Carchesium polypinum, 
Vaginicola valvata, Ameba crassa? Cothurnia maritima, with 
its variety, the C. incisa (mihi), &c. 
On Monocuromatic Intumination. By J. J. Woopwarp, 
Brevet Lieut.-Colonel, Assist.-Surgeon, U. 8. Army, in 
charge of Medical Microscopical Sections, Army Medical 
Museum. 
Srnce 1865 I have been in the habit of using monochro- 
matic (violet) light, not only for photo-micrography in my 
own hands and those of my able assistant, Dr. Edward 
Curtis, Assist.-Surgeon and Brevet-Major, U.S. Army, but 
also for all microscopic work requiring the sharpest defini- 
tion, as, for example, the examination of the finest Diatomacea, 
the Nobert’s lines, &c. 
I obtain the violet light by passing the direct light of the 
sun through a saturated solution of sulphate of copper in 
aqua ammonia, as originally suggested by Von Baer, in his 
‘ Kinleitung in die Héhere Optik,’ p. 48, the solution being 
held in a plate-glass cell, with parallel sides, and about the 
}th of an inch apart. The light thus obtained is concentrated 
