332 THE AMERICAN NATURALIST. [Vor. XXXIV. 
Sporulation in Amæba. — C. Scheel’ describes and figures a 
most interesting method of reproduction in Am@eba proteus observed 
in the winter of 1897—98. The conditions leading to this hitherto un- 
known method of rapid increase in this fresh-water Amceba could not 
be determined, nor could various experiments bring about the same 
results in material from the same locality, examined in 1898-99. 
The Ameeba was studied both alive and in prepared sections and 
a pretty complete series of stages obtained. 
The creature draws in its pseudopodia, takes on a spheroidal form, 
and then secretes a cyst or case that ultimately shows three succes- 
sive layers. Within this the Amceba rotates rapidly, once a second, 
in all directions with frequent change; it looks as if ciliated, but no 
evidence of cilia was found, and its motions may be due to pseu- 
dopodia. After several days this rotation ceases. 
In one case a contracting vacuole was seen discharging rhythmi- 
cally to the exterior, when the cyst was partly formed. 
The nucleus divides into pieces, and when there are about 20-30 
they become arranged near the surface. These in turn continue to 
divide until 500-600 small nuclei are formed in the outer part of 
the Amceba, while the central part has none. Cell walls appear about 
the nuclei, first about the outermost ones, and gradually the pieces 
of protoplasm so circumscribed separate as small Amcebas. These 
break out through the cyst, which has in the mean time become 
softened and broken up. 
The whole process lasts from two and a half to three months. 
In this way hundreds of small Amcebas, 10—14 p in diameter, are 
set free at one time. 
The author was able to isolate the young and rear them to recog- 
nizable Amæba proteus in two and a half to three weeks. EA X 
Notes. — The second number of Vol. I of the Biological Bulletin 
contains the following articles: * The Early Stages in the Develop- 
ment of the Hypophysis of Amia calva,” by J. M. Prather; “ An 
Extraordinary New Maritime Fly,” by V. L. Kellogg; ‘On the Varia- 
tion in the Position of the Stolon in Autolytus," by P. C. Mensch; 
* Gordiacez from the Cope Collection," by T. H. Montgomery, Jr. ; 
and “ A Preliminary Account of the Spermatogenesis of Batrachoseps 
attenuatus, Polymorphous Spermatogonia, Auxocytes, and Spermato- 
cytes," by G. Eisen. 
l Beiträge zur Fortpflanzung der Amoeben. Festschrift Carl von Kupfers, 
Jena, 1899. 
