228 MR. W. ARCHER ON THE MINUTE STRUCTURE AND 
though these sometimes reach only the formation of a ramification-cell—as indeed the 
effort to produce pinnelle at the apices of some of the plumes lower down may get no 
further than the same preliminary stage. 
In the “ typical" form the ramifications given off from the cortical stratum are much 
more prone themselves to branch than in Mr. Moseley's. Several branches (from three 
to ten) are given off, generally alternately, in quick succession, and radiate in a kind 
of fan-like manner; each possesses always a preceding ramification-cell (five-sided when 
the branch is formed), as in Mr. Moseley's plant. Тһе pits and stoppers are present, 
but not so conspicuously evident. 
The differences between the “ typical" В. callitricha and В. Hombroniana are very 
graphically shown in Mr. Tuffen West’s delicately rendered drawings. More distinct 
still than they are from each other, appears Mr. Moseley’s plant from either. 
At first glance, Ballia scoparia, Harvey, seems hardly to belong to the same genus. 
Distinct as is the habit, and divergent as is this plant in several details from the pre- 
ceding forms, there is still a good deal in common; but possibly, after all, the same 
characteristics may yet be found to be more forcibly presented in other algee. So far as 
regards the pits, they are not confined to Ballia in Rhodophyces ; these, as “ pores,” 
have long ago been pointed out by Nägeli. It is the “ stoppers” (so called) which 
I fancy to be new. | 
Now in B. scoparia the pits are generally pretty evident, the stoppers not readily 
seen, presenting themselves as only little thin discoid bodies (Pl. XXIX. figs. 8-9). It 
likewise possesses a plexus of threads on the principal stems, of which more below. 
. Like the former, this species branches by interposition of *ramification-cells;" but 
these and the mode of branching are quite dissimilar. 
Its general habit is aptly enough indicated by Dr. Harvey's specific name :—long-drawn- 
out and fastigiate; the “branches” scarcely thinner than the “stems,” most irregularly 
given off at no particular intervals, and only at one side, and branches fitfully again 
branching (Pl. XXIX. fig. 2). The branches stand off with a slight curve from the cell 
on which they originate, and then proceed upwards at an acute angle to the “ stem.” 
The ends of the joints appear to be slightly hollowed; and the adjacent upper and lower 
ends mutually somewhat overlap, the outer lower margins being convexly rounded 
(figs. 8, 9). The upper portions of the branches give off unilaterally a succession of 8 
few (1-5-6) of short spine-like uncinate bluntly acuminate branchlets (fig. 3); and when 
these are formed, that branch which bears them grows upwards no more; that is, its 
terminal cell ceases to subdivide, and its apex becomes acuminate, like the lateral spine- 
like branchlets. 
Now the formation of the ramification-cell is puzzling. When a young one is viewed 
edgeways, it seems to form a lenticular hollowing in the thick wall of the joint (fig. 6); 
but how that could so originate is very questionable. It may be formed by a deposition 
of membrane all round the joint, but so as to shut out a portion of the ** contents," 
which assumes that figure. Viewed from the “ front” (fig. 9), this as yet very thin cell 
is seen to be of broadly elliptic figure, showing a minute sharply marked pit and stopper 
exactly in the centre. More grown, and viewed edgeways, one of these cells appears 
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