30 Mr M. C. Potter, On Epiclemmydia lusitanica, —[Nov. 8, 
authors observed that, in the quiescent winter condition of the 
bulb, there are patches of callus—easily made conspicuous by 
staining with corallin—on the transverse walls. From this they 
infer that the transverse walls are perforated, the canals through 
them being open in the active, and closed by callus in the 
quiescent condition of the bulb, just as is the case with sieve- 
tubes. This inference has, however, to be confirmed by an investi- 
gation of the bulb in the active condition. The authors also 
observed that each segment of a vesicular vessel contains a large 
nucleus. 
(3) On Epiclemmydia Lusitanica a new genus of alge. By 
M. C. Potter, M.A. 
In the southern parts of Spain and Portugal, where rain falls 
generally only during the winter and spring months, numerous 
pools remain throughout the summer in the beds of the dried-up 
streams. To these pools collect during the summer numerous 
water loving animals among which we find water Tortoises. 
These Tortoises remain a great deal in the water and their shells 
on this account afford a suitable nidus for alge. 
The alga, which is the subject of this paper, appears to the 
naked eye as roundish patches of a deep green colour and occurs 
generally on the back, but sometimes on the under surface of the 
Tortoise near its margin. 
On cutting sections of one of there patches in a direction 
perpendicular to the surface of the animal’s back, we find the alga 
to consist of a number of squarish cells, some of ‘which are closely 
applied to the surface of the Tortoise shell and exposed to the 
action of the water in which the Tortoise lives, and others forming 
wedge-shaped masses which penetrate into the Tortoise shell. 
The cells of the alga divide in planes parallel and perpen- 
dicular to the back of the Tortoise; and by these divisions new 
cells are continually being formed, but the mass of cells where 
exposed is never more than a few layers thick, the outermost 
layer continually forming zoospores or being destroyed. These 
cells are closely applied to the surface of Tortoise shell and are 
continually trying to penetrate into it. The algal cells are only 
able to penetrate into the Tortoise shell by means of any cracks 
which may occur; so that whenever an algal cell reaches or finds 
a crack it immediately grows into the crack. At first when the 
crack is small only a small piece of algal cell can penetrate; this 
small piece however grows and spreads parallel to the surface of the 
Tortoise, and divides into cells by planes perpendicular, and when 
