E. W. BERGER ON THE CUBOMEDUS. 4] 
Most of my series were cut 4u in thickness. All in all I cut 
sixty-five clubs besides making some maceration preparations from 
material preserved for that purpose. These sixty-five series represent 
material from fourteen bottles. As a whole, my material was good, 
but the material from one bottle was decidedly superior for showing 
the axial fibers of the prisms and pyramids of the retinal cells. 
This shows the advantage of plenty of material. It will be evident 
that I had plenty of material. 
I found iron-hematoxylin the most satisfactory stain. I stained 
for a shorter or a longer time—one-half to several hours and longer— 
and then washed out the sections until under a low power of mag- 
nification they appeared quite unstained, the nuclei and a few other 
parts only appearing darkly stained. 
Depigmentation I practiced but little. I obtained many of my 
series almost wholly unpigmented, especially those I cut last. Others, 
of course, were very heavily pigmented. I am not certain but that 
alcohol slowly dissolves out the pigment after a long period of 
preservation. Slight variations in the technique of killing and pre- 
serving may also, perhaps, determine the stability or solubility of the 
pigment, as, of course, also the condition of the pigment at the time 
of killing. 
Anatomy.—For a short epitome of the anatomy of a Cubomedusa 
and of a Cubomedusan sensory club see p. 2 of the Introduction. 
The Distal Complex Eye—General.—The distal (larger) complex eye 
(Fig. 7) and the proximal (smaller) complex eye (Fig. 13) are so 
named to distinguish them from the lateral simple eyes of the clubs. 
The distal complex eye consists of the following parts: a cellular 
cornea, continuous with the epithelium of the sensory club; a cellular 
lens (externally cellular and internally often quite homogeneous) 
immediately beneath the cornea; a homogeneous capsule just internal 
from the iens, and evidently a secretion from the lens cells; a 
vitreous body composed primarily of prisms and pyramids just 
beneath the capsule; and a retina of pigmented cells, with sub- 
retinal nerve tissue, ganglion cells and fibers. To my knowledge 
all observers (except Carriére, who missed the capsule) are quite 
agreed on the anatomical structure of the distal complex eye as also 
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