1887.] MICROSCOPICAL JOURNAL. 47 
stance as fat. (5). Zhe crystals, which are present only during the repro- 
ductive period, are distinguished into large forms, which do not pass into the 
spores, and small forms which do. They are never truly crystalline. The 
large forms are excretions ; the small ones consist of an organic substance and 
are reserve material. (6). Zhe pigment also occurs in the reproducing 
forms, is never diffuse but always granular, varies from blue to reddish violet, 
and appears simultaneously with the crystals. They are excretory masses, 
formed during the spore-building, and are left behind. Their chemical reac- 
tions are noted in detail. (7). Zhe connecting jelly-like substance is nor- 
mally present and is of great importance in keeping the colony together. It 
increases throughout the vegetative period both in mass and consistence, and 
becomes sometimes almost cartilaginous. It disappears rapidly in con- 
fined specimens. After the appearance of the zodspores it also decreases, 
first slowly and then rapidly. Even in dead spirit-specimens some physical 
properties, e. 2., of swelling out again in water, remain. Morphologically 
this substance is an excretion of the protoplasm. Physiologically, it is essen- 
tial to the connectedness, protection, hydrostatic, and even nutritive functions 
of the colony. (8). Vaczoles are not present in very young colonies. As 
the jelly-like substance becomes separated from the penetrating fluid, 
vacuoles are formed, to disappear again as spore-formation begins. They 
are surrounded by a fine plasmic layer. The variations in form and 
distribution are noted. The author regards them as entirely comparable 
to the vacuoles of other Protozoa. (9). Zhe skeleton.—The presence or 
absence of a skeleton cannot be regarded as establishing a natural division. 
In noting the mode of growth Brandt maintains the existence of an organic 
basis with subsequent silicification. He deprecates the erection of species 
on the variations of the spicules. (10). Yel/ow cel/ls.—These symbions, 
which Brandt has named Zodxanthella, are regarded as perhaps allied to the 
Peridinee. The results of assimilation are starch grains, and also granules 
of different composition. Their presence at different periods, their behavior 
when isolated, and other points are then noted. (11). Lzd¢viduality of the 
colontes.—Colonies of different species cannot fuse, but colonies of the same 
species may, and that independent of the developmental stages of the two 
fusing forms. As Schneider has shown, artificial division is readily prac- 
ticable. There is more division of labor within the colony than Hertwig 
allowed. The functions of intra- and extra-capsular protoplasms are quite 
distinct. The central capsule even, which solely forms the spores, is not 
homogeneous in its functions. 
Il. Biology.—(1). NMutrztéon.—After noting general facts as to food ma- 
terial, Brandt emphasizes the truly nutritive function of the symbiotic alge, 
which contribute the results of their assimilation (starch, etc.) to their ani- 
mal host. The breaking up of these ‘‘ yellow cells” during swarm-formation 
is’ specially noted, and also the changes in the assimilative protoplasm. (2). 
Movement.—The plasmic portions being much heavier than sea water are 
floated by the vacuoles and by the gallert substance, which sometimes appear 
to be lighter than sea-water, and enormously increase the surface. Mechan- 
ical and thermal stimuli produce changes which effect sinking and rising. 
The pseudopodia affect the specific gravity through their influence on the 
vacuoles. (3). Occurrence of different forms.—The distribution of the 
species is described in detail, and graphically expressed in curves. THe 
principal result shows their varied occurrence at different seasons. (4). Az- 
vironment. (a) The Spherozoa are very sensitive to changes of salinity. (6) 
They are uninfluenced by light ; even extreme illumination does not affect their 
vertical distribution. The statement of Geddes that radiolarians move from the 
light is denied. (c) Apart from seasonal changes, alterations of temperature 
