No. 420.] HISTORY OF STICHOSTEMM A. IOO5 
season, apparently as a means of getting rid of a portion of 
the body which has become of little use. 
I have never observed spontaneous fission or fragmentation 
in Stichostemma, and have never found pieces or fragments 
which might be the result of such fission. Occasionally speci- 
mens are found which show slight constriction at some points, 
but isolation and continued observation of these individuals 
have always been without result. These constrictions appear 
not only in individuals with mature sexual products, but in 
other stages, and usually disappear after a few days. More- 
over, they are frequently irregular, being more pronounced on 
one side of the body than on the other. I am inclined to 
believe that they are merely the results of slight injuries, 
for slight cuts in the sides of the body produce results which 
are indistinguishable from those found in freshly collected 
specimens. 
HULL ZoóLoGiCAL LABORATORY, 
UNIVERSITY OF CHICAGO, July, 1901. 
LITERATURE. 
'97 BENHAM, W. B. Fission in Nemertines. Quart. Journ. Mir. Sci. 
Vol. xxxix. 
'98 BónwrG, L. Beiträge zur Anatomie und Histologie der Nemertinen. 
Zeitschr. f. wiss. Zool. Bd. lxiv, Heft 3. 
01 Hott, E. B., and LEE, F. S. The Theory of Phototactic Response. 
Am. Journ. Physiol. Vol. iv, No. 9. 
'90 Lors, J. Der Heliotropismus der Thiere und seine Uebereinstim- 
mung mit dem Heliotropismus der Pflanzen. Würzburg. 
'03 Lors, J. Ueber künstliche Umwandlung positiv heliotropischer Thiere 
in negativ heliotropische und umgekehrt. 4 rch. f. d. ges. Physiol. 
'95 Pea T. H. Stichostemma eilhardi zov. gen., nov. sp. 
Zeitschr. f. wiss. Zool. Bd. lix. 
'96 MONTGOMERY, T. H.  Stichostemma asensoriatum nov. sf. a 
Fresh-Water Nemertean from Pennsylvania. Zool. Anz. Bd. xix, 
No. 515. 
