66 The American Naturalist. [ January, 
ZOOLOGY. 
The Relation of Nuclei and Cyptoplasm in the Intestinal 
Cells of Land Isopods.'—Somewhat more than two years ago the 
late Professor Ryder and Miss Pennington (Anat. Anzeiger, Bd. IX, 
Nr. 24 & 25) announced the discovery of the fact that nuclei in the 
adjacent cells of the intestinal epithelium of Porcellio may become 
amoeboid, wander toward each other, and in some cases fuse together. 
This surprising fact the authors mentioned interpreted as a non-sexual 
form of conjugation; and, while recognizing its unique character, did 
not doubt that it was a normal phenomenon, even suggesting that it 
might have some relation to sexual conjugation. : 
Owing, however, to the entire novelty of these observations and inter- 
pretations the paper was received by many persons with considerable 
reserve. One author, W. Schimkewitsch (C. R. Soc. Natural., St. Pe- — 
tersbourg, 1895, I, and Biolog. Centralblatt, Bd. XVI, Nr. 5), while — 
confirming the observation, denied that the nuclear fusion was a normal — 
phenomenon. He interpreted it not as a form of nuclear conjugation } 
but simply as as an artifact. : 
In the course of a study of amitosis, upon which I was engaged, it 
occurred to me that the phenomenon is question might be an irregular 
form of direct nuclear division ; and with the approval of Dr. Mary — 
Pennington, the junior author of the paper first mentioned, I undertook — 
a review of that work. i 
My observations began with Porcellio, and were then extended to ‘ 
Oniscus and Armadillidium. On the whole the results of this review — 
confirm the conclusions of Schimkewitsch. The phenomenon, which — 
may be readily observed, is in most cases neither a form of nuclear con- — 
jugation nor division, but simply an artifact. I was first impr i 
with the fact, as was also Schimkewitsch, that in the most carefully pre 
served preparations relatively few of these so-called “ conjugating 
nuclei” were found; on the other hand, in cases where the intestine 
was cut open before fixation, or was in other ways roughly handled, 
many of them occurred. 
The shape and structure of these nuclei is such as to suggest the idea 
that they have been squeezed out of shape by some sort of pressure. 
They are most frequently long and pointed, with the chromatic substance 
condensed at one end, and with an empty nuclear membrane at 
other, Figs. 1,2 and 3. In some cases these nuclear processes are 
‘Contributions from the Zoological Laboratory of University of Pennsylvania, 
No. VI. : . 
