IOO 
Elizabeth Acton. 
There is an irregular, lobed, parietal chloroplast and starch 
grains are nearly always present. They are often so abundant 
that they completely fill the cell (Text-fig. 2, E). The cells are 
multinucleate, 1 to 6 nuclei being present in a cell. 
Multiplication. 
Multiplication takes place by cells which become detached from 
the thallus. These may be either intercalary or terminal. 
Frequently the end cell appears to break away and germinate 
without a resting stage; or intercalary cells may round themselves 
off and develop a thick cell-wall as in Text-fig 2, E. Text-fig. 2, F 
shews a similar spore germinating. 
No motile method of reproduction has been observed. Yet 
it is evident that such a state can exist, for the alga must have 
entered the cracks in the glaze of the pie-dish by means of minute 
motile spores. External conditions must have arisen which caused 
the formation of a large number of motile reproductive bodies, but 
no trace of these could be found. 
Systematic Position. 
In discussing the systematic position of this alga, it will only 
be necessary to consider the chlorophyll-green penetrating algae 
which have previously been described, for it is undoubtedly a 
member of the Chlorophyceae. 
Among these there are three genera— Gomontia, Teltamia and 
Foreliella —to which this alga bears some resemblance. 
In 1889, Bornet and Flahault 1 founded the genus Gomontia to 
contain a shell-boring alga which they named Gomontia polyrhiza. 
The reproductive stage of this plant had already been described by 
Lagerheim 2 as a new species under the name Codiolum polyrhizum. 
In 1895, Batters 3 described two shell-boring algae which he 
placed in a new genus Teltamia, and in 1898, Chodat 4 founded a new 
genus Foreliella to contain his new species Foreliella perforans 
which penetrates the shell of the fresh-water mussel. 
These three genera have many points in common, but Tellamia 
seems to be separated from the other two and from the alga under 
consideration by the form of its thallus. 
1 Bornet et Flahault. “ Sur quelques plantes vivant dans le teste calcaire 
des mollusques.” Bull. Soc. Bot. France, T. xxxvi, 1889. 
2 Lagerheim. “ Ett Bidrag till Fanned ora Slagtet Codiolum A. Br.” 
Oefvers. af Kongl. Vet. Akad. Forhandl., 1885. 
3 Batters. “ On some new British Marine Algae.” Ann. of Bot., 1895. 
4 Chodat. “ Etudes de Biologie Lacustre.” Bull. del’Herbier Boissier, 
June, 1898. 
