OLIVE : MONOGRAPH OF THE ACRASIEAE. 
463 
The individuals of Guttulina, for example, have normally the form 
oi Amoeba Umax (pi. 5, fig. 35) without pseudopodia; Fayod 
asserts, however, that those of Guttulina protea throw out pseudo¬ 
podia under certain unfavorable conditions, such as occur when 
numerous bacteria are present, or when the nourishment is concen¬ 
trated. The myxamoebae of Sappinia and Guttulinopsis, on the 
other hand, normally possess lobose or rounded projections (pi. 5, 
figs. 4, 6, 15, 17). When growing Dictyostelium on hanging drop 
cultures, it was noticed that an insufficient amount of water causes 
the individuals to assume also an abnormal shape ; they become nod¬ 
ulose and the protoplasm appears dense, while the movement under 
these conditions is extremely slow (pi. 6, figs. 63, 64). 
With the one exception of Guttulina rosea, in which, according 
to Cienkowsky, the protoplasm is reddish, no distinct color can be 
seen in the cytoplasm of the myxamoebae of any of the species in 
the vegetative stage. Granules of varying size and distinctness may 
usually be observed shifting about in the internal streaming, some of 
which are probably the chromatic bodies of the nuclei, while others 
may be bodies which have been ingested or which represent certain 
products of metabolism. As Brefeld asserts, the nuclei in the 
myxamoebae seem to vary in distinctness during the vegetative con¬ 
dition ; this change is probably due to the varying size and degree 
of refractiveness of the component granules. 
The secondary division of the myxamoebae. — After a more or 
less prolonged vegetative existence on a nutrient substratum, during 
which the myxamoebae increase in size, they finally divide, becoming 
thus rapidly multiplied. Just how many times division of a single 
individual and of its derivatives may occur, can hardly be determined 
without continuous observation through several days; the number 
undoubtedly varies, however, with the amount of available moisture 
and food. In preparing for division, the myxamoeba becomes more 
or less elongated, the contour becomes more regular through the 
withdrawal of the pseudopodia, and a constriction appears which 
finally divides the individual into two more or less equal parts, each 
part receiving one or more of the deeply-staining nuclear bodies 
(pi. 5, fig. 18; pi. 6, fig. 66-73). The whole process takes place in 
a comparatively short time, a minute or even less usually sufficing 
for its completion. Instances may sometimes be observed in which 
the connecting isthmus between the two halves becomes almost 
