XV, 6 
Shaw : Camp bellosphaera 
507 
soon as the membrane ceases to conform with the segmentation 
products of the protoplast, the outer limit is visible only in cases 
of more or less deeply stained material. Examples of such are 
found on slides bearing material stained with Bismarck brown 
alone (Nos. 1 and 3). In the shrunken, Venetian turpentine 
preparations each gonidium is surrounded by a membrane which 
has almost no thickness on the outer side, but reaches to the 
center of the coenobium on the inner side, grading from one side 
to the other in such a way that the cavity of the coenobium is 
filled with the substance of these walls, except for very small 
interstitial spaces where three of the walls meet, and a large 
space in the anterior quarter of the coenobium. The very thin 
outer part of the gonidium wall has an extent of about a fourth 
or fifth of the circumference of the gonidium, and a correspond- 
ing superficial area of the gonidial protoplast is in close relation- 
ship with neighboring somatic cells. A large proportion of the 
shrinkage that occurs in the Venetian turpentine specimens 
takes place in the gelatinous matrix, if there be such, which 
fills the coenobial cavity. 
The natural form of the membranes of the gonidial cells is 
best shown by specimens near the margins of the cover glasses of 
the type slide and others of the same and sister lots of Venetian 
turpentine preparations. The marginal and submarginal speci- 
mens on these slides are swollen instead of shrunken like those 
which make up the bulk of the preparation. This is true under 
about the marginal millimeter of the 24 millimeter square covers. 
The specimens here are beautifully plump. In fact many of 
them seem to be excessively turgid. The swelling involves only 
the cell membranes and not the protoplasts. It is most marked 
at the edge of the cover and in a space the greater part of a 
millimeter in width. Then, in a narrower zone, the specimens 
grade off from terete to shrunken. The marginal specimens are 
also faded. The Bismarck brown is here more rapidly and com- 
pletely faded than the nigrosin stain, in both the single- and 
double-stained material. The most beautiful of the specimens 
are the coenobia in which full expansion of the cell walls has 
been accompanied by a certain degree of bleaching. In some 
of these, careful focusing reveals the gonidial membranes. In a 
coenobium with well-developed gonidia it can be seen that over 
an area on the outer side of the gonidium its membrane is very 
thin, as noted in the shrunken specimens, and that on the inner 
side it is very thick — thicker than in the shrunken specimens — 
so thick as almost to fill the central cavity of the coenobium and 
