IOI 
On a New Penetrating Alga. 
Two species 7'. contorta and T. intricata were described, both 
of which penetrate the periostracum of mollusc shells. The thallus 
is a flat expansion not bearing special penetrating branches. 
Batters himself places the genus near Endoderma. It is difficult to 
see why the genus Tellamia was formed, for there seems to be no 
reasonable objection to placing both T. contorta and T. intricata in 
the genus Endoderma which already existed. 
The alga under consideration resembles very closely both 
Foreliella perforans and Gomontia polyrhiza. The question there¬ 
fore arises as to what characters separate these two genera. 
According to Chodat, who is responsible for this genus, Foreliella 
only differs from Gomontia in three points:—the chromatophore is 
different, the cell is uninucleate and the thallus is more markedly 
perforating. He does not state how the chromatophores differ 
and as far as can be ascertained there is no important difference. 
The fact that the cells are multinucleate in Gomontia and 
uninucleate in Foreliella is not sufficient to separate the two 
genera, nor is the fact that the thallus is more markedly perforating 
in the one case than in the other. This latter fact is probably 
largely due to circumstance. The shell of Anodon is very soft 
compared with the shells perforated by Gomontia and therefore 
offers less resistance to the passage of the penetrating branches. 
There is therefore no valid reason for separating Foreliella 
from Gomontia , and Foreliella perforans should be known as 
Gomontia perforans. 
The new alga is evidently a species of Gomontia. The alga is 
perforating, the thallus consists of filaments radiating from a 
central point, and these branch dichotomously giving off in addition 
penetrating branches. The cells have a parietal, lobed chloroplast 
1-6 nuclei, and they are crowded with starch grains. All these 
facts are characteristic of Gomontia. 
It differs slightly from the species G. polyrhiza in size and also 
in the shape of its cells. The terminal cells in G. polyrhiza are 
usually club-shaped, swollen at the end. In the new species they 
frequently taper towards the end. 
Chodat 1 mentions a species G. Manxiana. I have not been able 
to find any description or any other mention of this species, so 
that it is impossible to discuss it here. 
Collins 2 in 1897 described a fresh-water species G. Holdenii 
’ Chodat. “ Algues vertes de la Suisse.” p. 61. 
2 F. S. Collins. “ Some perforating and other Algae on fresh-water 
shells.” Erythea, Vol. V, No. y, 1897. 
