MODE OF GROWTH OF A2ALLIA CALLITRICHA. 219 
raehis, the other in apposition with the longer portion of the lower joint of the rachis 
respectively. 
The upper (subhemispherieal) portion of the ramification-cell, thus eut off by the 
eurved, hollowed, oblique septum, is the first joint of a simple branch or (it may be 
eventually) of a subsidiary rachis (Pl. XXVIII. figs. 10 & 11). Before taking leave of 
this cell for the present, it is only necessary to say that at the middle of the septum is 
formed a pit—a double pit, it will be, of course, understood, each with its stopper. At 
this point, then, the five-sided ramification-cell has now, of course, two pits—one, as 
explained, opposite the corresponding pit of the rachis-cell, the other (younger) cor- 
responding to the pit of the basal cell of the branch; and as the former pair of pits, 
with their stoppers, are smaller than those at the ends of the rachis-cell, so the latter, 
in their turn, are smaller still than the former. 
À ramifieation-cell having reached this point may seemingly remain permanently so 
(in Mr. Moseley's plant many, by far the majority, do во); but certain of them proceed 
further. . 
If then they proceed to further development, the next stage is that from a point from 
about a third to scarcely half way from the outer side of the septum, cutting off the first 
branch-joint from the ramification-cell, a fresh curved and hollowed septum is produced ; 
this extends thence to about the middle of the lower and outer free and exposed (external) 
side of the ramification-cell, its concave side outward—that is, its convex side (as before) 
towards the cavity of the ramification-cell (6, in figs. 10 & 11). This latter has now 
reached the six-sided form above mentioned. Obviously the portion cut off therefrom 
is at first triangular, with only one exposed or external side—this being, in fact, the 
upper portion of the lower free and external side of the primary ramification-cell, which 
lower portion whereof still forms one of its boundaries, and of course still free and 
external. Again, we have to note the formation in this second septum of the opposite 
pairs of pits and their stoppers, occupying a position about one third of the distance 
from the lower end of the septum. The primary ramification-cell at this point, it will 
be seen, has now three pits—the third and last formed being that in the freshly formed 
septum, and placed at a point about a third of the distance from its lower end, and 
opposite to which it has its fellow pit and stopper. 
The triangular portion so cut off (which has one pit, with its stopper, in the septum 
between it and the other ramification-cell, being that first mentioned), like its prede- 
cessor, grows out at first laterally, and then obliquely upwards in a roundly inflated 
manner, this projecting portion being soon cut off by a fresh septum in such a way that | 
the lower remains as a five-sided cell. This latter may, in fact, be denominated a rami- 
fication-cell of the second degree (ғ 2, figs. 10 & 11); and the upper portion cut off 
therefrom forms the basal or primary joint of a secondary or accessory branch—the septum 
30 cutting it off bearing again its medium pair of pits and stoppers, still smaller in size. 
_ The five sides of the ramification-cell of the second degree, when the basal cell of 
the accessory branch is cut off, are thus made up:—1st. The upper portion of what 
Was once the outer free side of the ramification-cell of the first degree, now pushed out 
laterally and obliquely (1”); 2nd. The septum cutting it off therefrom (2”); 3rd. The 
