LI 
DESCRIPTION OF BALLIA. 193 
Alge in the Siphonee; that of Sphacelaria, though rigid, is 
more of the nature of the cellular tissue of other Algæ. But the 
structure of the joints presents a still more striking character ; 
each joint is concave at its superior end, convex at its inferior, 
having thus a somewhat cordate figure, the convex end being 
inserted into the joint immediately below it, while the concave 
receives in like manner the one above. These joints consist 
of a single cellule, and contain a bag of colouring matter 
Which is collapsed in a dried state. The ramuli do not ap- 
pear to spring from these, but from accessory cellules placed 
at the upper end of the main cellule of the joint, and con- 
necting it with the joint next above it. 
Mr Brown suggests, that Agardh’s Sphacelaria callitricha 
may be only our plant in a faded state—an opinion that I 
think highly probable, as the Ballia assumes in decay a pale 
green colour. The magnified portion offers some slight dis- 
crepancies, chiefly that the ramuli are less close. The.joints 
appear to be of the same peculiar construction. In winter, 
the Ballia is frequently found entirely destitute of the jointed 
and pinnated ramuli, or merely clothed with their remains, 
and Mr Brown supposes that this annual shedding of its 
lesser branches may be connected with the propagation of 
the plant. Perhaps, the sporular mass which generally ter- 
Minates the rachides of the pinnated-ramuli or plumules, may 
be retained till these are thrown off. Many other Alge, it is 
Vell known, are deciduous in a similar manner. 
LJ 
Tas. IX.—Ballia Brunonia. Fig. 1. Plant, nat. size; 
E. 2, 3. portions of branches; f. 4. portions of the main stem; 
f 3. jointed hairs or fibres with which the main stem is 
clothed :—more or less magnified. 
~~ Yo UuuNe o Ne 
