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ESTERLY: EUCALANUS. 29 
with iron-haematoxylin (Plate 2, Fig. 23), or in Mallory’s connective- 
tissue stain (Plate 5, Figs. 44, 50). Even the granules of the cyto- 
plasm take part in the general radiate arrangement. It is also very 
plain that the contents of the cells are more densely aggregated nearer 
the basal plates than toward their distal ends (Plate 5, Fig. 50). 
It is difficult to say whether this striation is in any way related to the 
“Streifung”’ which Hesse notes in connection with the “Stiftchen- 
saum.” But in my opinion the denser condition of the cell contents, 
as well as the striated appearance in the retinal cells, is an expression 
of the greater secretory activity of the cells in that region, the product 
of which is shown in the basal plates, since the latter must be regarded 
as products of the retinal cells, for there are no others from which they 
can reasonably be derived. 
Such striations are strikingly shown, also, in the cells of the digestive 
tract in EKucalanus (Plate 4, Fig. 52), where it is very unlikely that they 
can be regarded as due to the presence of end fibrillae of nerves spread- 
ing out into the cell contents.. This condition of the digestive-cells, 
I believe, is strictly in line with that shown by Mark(’76) to exist in 
the cells of the salivary glands of certain Coccidae. 
The true character of the neurofibrillae is shown in such a drawing 
as Figure 49 (Plate 5), where, in the cells of the ventral eye, the struc- 
tures that I take to be the neurofibrillae of the axis cylinders are shown 
as rather heavy, beaded bodies (n. fbri.). These lie at a very low 
focus in the section (a fact which cannot be expressed in the drawing), 
and are in all likelihood parts of the two nerve fibres shown in a cor- 
responding position in Figure 45. In the left lateral eyes (Fig. 49, 
ocl. s.) there are two nerve fibres which may be seen to be directly 
connected with similar structures. In the right eye one such is shown. 
The nerve endings when shown in their entire extent (as I believe is the 
case in Figure 49, n. fbri.) stand out with remarkable clearness from 
the rest of the cell, and they take a tint almost precisely the same 
as that of the nerve fibres outside the cells. It is not unlikely that 
some of the granular appearance in the basal parts of the cells of the 
eyes is due to the presence of the beaded nerve-terminations. This is 
indicated rather strongly in the right lateral ocellus shown in Figure 
49. 
As far as my observations go, therefore, the median eye of the 
Copepoda does not resemble the eye of the flatworms in having the 
recipient ends of the nerves turned toward the pigment, nor in the 
character of the nerve ending, since it does not possess a “‘Stiftchen- 
saum’’ in the sense in which Hesse uses the word. It might be said 
