CHLOROPHYCEA 157 
shrinks into the great lumen of the cell-sap cavity 
and leaves the plant as a translucent sphere. In 
this condition it frequently parts company with its 
attachment and floating to the surface is drifted 
ashore. It is common in the West Indies, and 
reaches Bermuda, where the plants are often 
drifted ashore in this translucent state, and are 
called “ sea-bottles” by the inhabitants. Halicystis 
ovalis, which resembles this plant in shape, but is 
much smaller, occurs in the Clyde Sea area (and 
extends from western France to the Faroes and Scan- 
dinavia). Its systematic position is uncertain, since 
we know nothing of its reproduction, but so far as may 
be judged by the structure of its membrane, which 
shows none of the striation and very little of the 
stratification of Valonia, by its chromatophores, which 
have no pyrenoid, while those of Valonia possess 
one in many cases at least, and by the substitution 
of a sucker-like disc for rhizoids, it must be placed 
apart from Valonia. Schmitz suggests that its 
vegetative structure recalls the freshwater Botrydium 
most closely, and is mainly distinguished from it by 
the absence of rhizoids. However, this is true also 
of a comparison with Valonia, and until we know 
its reproduction any speculation must carry little 
weight. 
In other species of Valonia there occurs a remark- 
able form of branching, if it may be so termed. 
Small portions of protoplasm and chlorophyll gather 
opposite more or less definite parts of the mem- 
brane, generally near the apex, and separate them- 
selves from the rest of the contents by the formation 
