ESTERLY: EUCALANUS. 17 
(Fig. 1). ‘The only question connected with their occurrence is 
whether or not that is their normal form. ‘There can be no doubt that 
the rod-like forms are not optical sections or isolated portions of 
band-shaped bodies which have been so crumpled or folded as to be 
cut into many scattered bits. ‘There is the possibility, though I be- 
lieve it is remote, that both rod-like and band-like interior bodies 
occur in the retinal cells. 
‘The question as to the branching of the interior bodies, which was 
raised by Hesse, is a debatable one. My belief is that branching does 
not occur, though in some preparations it appears to (Plate 1, Fig. 5). 
Here, again, it seems probable that the branched appearance is due 
to the fact that numbers of rod-like bodies are closely massed together, 
the apparent branching being in reality due to the protrusion of the 
ends of certain spicules or groups of spicules from the more general 
ageregation of them. Indeed, the appearance of a branching habit 
seems to me to be strong evidence that the band-form of the interior 
body is really not the unit of structure in cases where it occurs, for 
often (Plate 1, Fig. 8) an end of an otherwise apparently homogeneous 
ribbon is frayed out. I am at a loss to account for this frayed or tas- 
seled structure except on the assumption that masses or groups of rods 
or spicules compose the ribbon. 
The interior bodies stain in the same way that the nuclei do. This 
holds for all of the staining methods I have employed. ‘The colora- 
tion is the same in the two objects in either iron-haematoxylin, Ehrlich’s 
haematoxylin or acid haemalum. Vom Rath’s fluid blackens or 
browns all the structures in the cell,— plasma, nucleus, and interior 
bodies, alike. But Mallory’s connective-tissue stain is especially good 
for differential staining.. When sections are treated in this way, 
the nuclei and interior bodies become yellow, all other structures red 
or reddish-purple, except chitin and connective tissue, which become 
blue. ‘The interior bodies are evidently highly differentiated portions 
of the cell, though there is no reason to think that they are in any way 
the equivalents of nuclear structures, since their appearance in rather 
heavily stained haematoxylin preparations is vitreous and refractive. 
This is true to some extent, also, in Mallory’s stain, and is especially 
evident if a vom Rath preparation is well decolorized in hydrogen 
peroxide. ‘The interior bodies are ordinarily as deeply stained as any 
other part of the retinal cells, but they decolorize more quickly and 
then appear as refractive or colorless objects in the brown cytoplasm. 
It is difficult to describe the interior bodies in general terms. ‘The 
isolated ones are rod-like or spindle-shaped, and this is in general the 
