142 Barber . — On the Str lecture of P achy theca. 
three cases, however, there is undoubted branching (Fig. 4). 
The cell-rows are separated from one another by a slightly- 
coloured matrix, and the distance between two adjacent 
cell-rows is as great, or slightly greater than the diameter of 
one of the cells. On the transverse walls are developed oval 
swellings, similar to the callus-plates or ‘ stoppers 5 of the 
Florideae or the swellings on the walls of Oscillatoria or Nostoc 
(Figs. 3, 4). 
In the central part the filaments are also divided by trans- 
verse walls : they appear to penetrate in all directions a clear 
colourless matrix (Figs. 2, 5, 6 , 7). In the section some 
appear to be cut transversely, and others obliquely, while 
some appear to run in the plane of the section. There is no 
well-marked branching ; and the stoppers appear to be absent 
from the transverse walls. The cells appear to be slightly 
less in diameter than those of the radiating filaments. 
It is at present impossible to say whether the cortical and 
central filaments are continuous. The filaments from the 
centre appear to have no connection with the oval bodies, 
but appear distinctly to wind in between them (Figs. 6, 7) ; 
and on tracing the filaments from the cortex inwards they 
also appear to pass between the oval bodies (Fig. 6). From 
the figures it will be seen that a direct continuity between the 
filaments of the different zones cannot be assumed. The walls 
of a cortical filament sometimes appear to be continuous with 
those of two contiguous oval bodies, while the central filaments 
appear to push themselves in between these latter. If this be 
so, the central filaments push themselves inside the cortical. 
There is, on the other hand, one case where an oval body 
appears distinctly to branch outwards into two radiating fila- 
ments, but it is not safe to lay stress on any isolated example. 
The main difficulty lies in the zone of oval bodies . Their 
shorter diameter is three or four times as great as that of 
the cortical filaments, while their length varies considerably 
(Figs. 2, 6, 7). In all cases there are well-marked inner 
walls separating them off sharply from the central matrix; 
but towards the cortex there is no such sharply-marked 
