HISTOLOGY OF CERTAIN SPECIES OF CORALLINACEJE. 205 
The terminal cells contain viscid protoplasm, dark granules, and a nucleus. Their 
sides are, after decalcifying, evidently in contact; and when the process has been only 
partially carried out, а granular mass of carbonate of lime is seen to hide the side walls 
of contiguous cells, and to intrude on their internal space. 
Having their side walls in contact after decalcifying, it is not probable that there 
ean have been much of the calcareous element between the cells; there was some 
in the cell-walls, and also in the position of the primordial utriele. There is, however, 
frequently a small amount of caleareous deposition in the distal end of these outer 
green cells, but not enough to cover the whole surface. Nevertheless, when the whole 
frond of Corallina officinalis has matured, the whole of the distal end is covered, and. 
thus the organie connexion between the superficial tissue and that beneath is destroyed. 
The proximal end of the outer green cells is in close contact with the upper wall of 
the cells beneath; and in the early days of the growth of the frond there is very little 
mineral deposition there: but later it occurs, so that finally these cells, and the others 
beneath them in the mass of the frond, are quite surrounded by opaque carbonate of lime, 
Which is, moreover, amongst their cell-walls and within to a certain extent. 
The superficial epithelial-looking layer of thé British Corallines, and of some from 
Port Natal, is the homologue of the delicate homogeneous layer covering the more 
rapidly growing and less calcareous Corallines of the Bermudas; and the flat cells of the 
one are the analogues of the long slender filamentous processes of the others. 
In some decalcified specimens from Bermuda the cell-wall of the cells supporting the 
processes, and of the deeper cells also, is very thick, and no pores are to be seen. 
After much, but not all, of the carbonate of lime has been removed, it is seen to be 
granular, to be ineluded in the substance of the walls, between them, and in the cell. 
And when this last state occurs all the solid contents are crowded up in the middle. 
In a young frond of Соғай па officinalis these outer cells are seen to be dotted on their 
sides with minute dark punctations after the action of acid. 
Beneath the outermost green-coloured layer of cells of Corallina officinalis are others 
of the same colour or else of a light port-wine tint. They have dark granules, some of 
considerable size, within them; and in the instance of the port-wine-coloured cells the 
colouring matter is in solution as well as in the granules. The cells are cubical or oval in 
outline, some being elongate; they are in close contact with those in front and behind ; 
but an intercellular space exists around the sides. That is to say, after decalcification, 
the slightest pressure will separate the sides of groups of cells; and it is in this position 
that the bulk of the calcareous element is deposited. This imperfect adhesion of ше 
sides and the decided organic connexion between the ends of the cells in linear series, 18 
more or less seen throughout the frond. 
In young fronds the cells, especially when ү 
E v aggregates ii enisi masses so as to exhibit a small moniliform 
series; and in the midst is a rather large nucleus and nucleolus. Sometimes кене is to 
be observed a large circular dark line encircling a small zone of diaphanous wall, in the 
midst of which 48 а circular dark spot. All these cells are distinctly tinted. (Plate 
XXVII. fig. 7.) | 
SECOND SERIES.—BOTANY, VOL. I. 
‘they are elongate, are crammed with 
26 
