PLATES 
EXPLANATION OF PLATES 
The drawings were made with the aid of a camera lucida, using a Zeiss 2-mm. 
apochromatic immersion objective, N. A. 1.30, and a Spencer compensating 
ocular 20 X which produced a magnification of 2633. The illumination consisted 
of light from a 100-watt frosted-globe Mazda concentrated-filament lamp passed 
through a daylight glass or a common cobalt-blue glass filter, and an Abbe con¬ 
denser. The observer was shaded from the light in front of him and from the 
sides by a black-cloth screen. 
In reproduction plates 1 to 8 have been reduced one-third, and plate 9 three- 
fourths, giving a final magnification of 1755 and 1316, respectively. 
Figures 1 to 20 represent complexes of class I; figures 21 and 23, complexes of 
class II. 
