MUSEUM OF COMPARATIVE ZOOLOGY. 177 
caliber of the opening (Figs. 10, 56), and thus to facilitate the passage of 
the egg mass. The hypodermis can hardly be followed around the bend 
under the infolded cuticula. If it exists there, it is certainly a very 
much attenuated layer. I do not think that the elongated cells of the 
bulb can be regarded as modified hypodermal cells. 
VI. Discussion. 
1. Dorsau OCELLS. 
The nature of the dorsal cells is not definitely determined, yet I have 
little doubt as to their nervous character. The interpretation of them 
as gland cells (Bürger, ’91) seems to me untenable for many reasons. 
The cells do not have at all the appearance of gland cells, there is no 
trace of any secretion in the cell or its process, nor anything in this pro- 
cess which suggests even remotely a duct, and finally one. finds no con- 
nection of the stalk with the iùtestine or with the exterior. Against the 
possibility that they may be degenerate gland cells, functional in larval 
life, it may be urged that there is absolutely no evidence of degeneration 
in the appearance of the cells. 
If the positive evidence on the other side be, examined, it will be 
found to be almost equally strong, and in favor of their nervous charac- 
ter. In the first place, their nuclei are like those of the large ganglion 
cells in affinity for stains, in the possession of one or two large homo- 
geneous nucleoli, and in the curious unstained enclosures already 
described. On the other hand, it cannot be denied that the nuclear 
membrane is more irregular, and seems to be connected with the fibres 
of the cell substance, a condition which was not seen in the large gan- 
glion cells. 
The stalks of these cells. certainly resemble nervous processes opti- 
cally, as well as in their relation to the cell body, and in their termina- 
tion, which has been considered in detail. Unless one regards the stalk 
as differentiated into a stainable and a non-stainable portion on account 
of some unknown difference in the chemical nature of the parts, it must 
be granted, I think, from the evidence previously produced, that the pro- 
cess branches at or near its termination in the brain. This branching 
seems to me to be an insuperable objection to the interpretation of these 
cells as glandular, and indeed to render it almost certain that they are 
nervous. Their enormous size and extremely fluid contents may be 
due to the freedom for growth which they enjoy in an unrestricted space, 
and, in part at least, to osmotic conditions. 
