No. 1.] MIDGUT OF THE TERRESTRIAL ISOPODS. 99 
slightly developed true endodermal “ midgut.” At all events the 
cell-divisions described were mitoses and not amitoses, and no 
trace of regeneration by amitotic division has yet been found 
in the Isopod “ midgut.” 
I do not wish it to be understood that I am denying the 
existence of amitosis in one form or another in the « midgut ” 
of the land Isopods; my point is that it cannot occur by any 
means as frequently as has been supposed, and that the pecu- 
liarly formed nuclei are not necessarily nuclei which are under- 
going amitosis. I have myself observed certain arrangements 
of nuclei, which I have represented in Figs. 7 and 8, and which 
seem to be explicable only as the result of a direct division of 
the nucleus; they represent, however, a Sragmentation of the 
nucleus rather than what is usually denoted amitosis. In some 
cells one or two small portions of nuclear substance may be 
found lying beside a nucleus, as is shown in Fig. 7, and in one 
instance (Fig. 8) I observed the results of the fragmentation of 
a nucleus into a number of small portions. Cases such as these 
I have found only in fully adult specimens, and I believe them 
to be the results of beginning disorganization rather than a 
multiplication of nuclei. 
It is interesting to find that the Isopod “ midgut ” has been 
held to furnish evidence not only of the occurrence of amitosis, 
but also of a reverse and more remarkable process, namely, a 
conjugation of nuclei. The late Prof. J. A. Ryder and one of 
his students, Miss Mary E. Pennington, have described (94) 
such as occurring in the “midgut” of Porcellio. The figures 
which they give to substantiate their conclusions may readily 
be duplicated, and in Fig. 3 I show some instances of the same 
phenomenon as they describe. But the interpretation of such 
peculiarities as a fusion of nuclei seems to me to be entirely 
unwarranted. Their mistake has arisen from a misconception 
of the true structure of the “ midgut ”’ epithelium; they have 
evidently regarded, just as Carnoy has done, the appearances 
seen with a high focus, to which I have referred in an earlier 
part of this paper, as denoting a perfect separation of the vari- 
ous cells, and have failed to perceive that we have really to do 
with a syncytium. 
