is slightly produced beyond them, forming an oblique mucro; their walls 
very thick, the mer portion formed of largish, polygonal cells, the outer 
of a stratum of closely packed vertical filaments. A very dense, broad, 
more or less clearly defined, sometimes obsolete mid-rib runs through the 
substance of the frond, and faint lateral, oblique veins proceed from it ; 
both formed of elongated, cylindrical cellules, disposed in longitudinal 
fibres. The cells composing the middle stratum of the frond are polygonal, 
gradually becoming smaller outwards ; and those of the periphery are very 
minute, and arranged in closely packed, vertical filaments. Colour a fine 
scarlet pink, dark in the main branches. Substance cartilaginous, imperfectly 
adhering to paper in drying. 
In reforming the genus Spherococcus, which, in the work of 
Agardh included a large number of species now dispersed into 
many genera, and many of which had little in common with each 
other except the spherical fruit, Dr. Greville confined the amended 
genus to the S. coronopifolius and to S. erinitus, Gm. The first 
of these, bemg the best known, is to be considered the type. 
Its structure is peculiar; under a pocket lens may be observed 
running through the branches the faint appearance of a mid-rib, 
connected with the margin by oblique lateral veins, both of which 
were first observed by Mr. Sowerby. By making a transverse 
section, and applying a more powerful glass, this venation is seen 
to be caused by an internal rib, composed of denser and more 
elongated cells than the rest of the frond; and if the imternal 
structure of the frond affords, m the Floridez, the surest generic 
characters, the presence of such a rib ought to be essential to the 
genus. Judged by this rule, my S. australis (Harv. in Hook. 
Lond. Journ, vol. i. p. 445), notwithstanding that outwardly it 
bears a close resemblance to S. coronopifolius, must be removed 
from the genus, its imternal structure being extremely lax, and 
more like that of Gracilaria, a group which, if allowed to retam 
all the species which seem disposed to drop into it, will soon be 
as anomalous as Spherococcus was formerly. 
S. coronopifolius appears to have been first noticed by Ray, in 
whose ‘Synopsis’ it is described. It is said to be unknown on 
the eastern coast of England. In Ireland it is more common, 
and is found at both sides of the island. In Scotland it is 
extremely rare. 
Fig. 1. SpumRococcus CORONOPIFOLIUS :—natural size. 2. Portion of a 
branchlet. 3. Section of a tubercle. 4. Spores. 5. Cross section of a 
main branch, in its lower part. 6. Longitudinal section of the same :—all 
more or less highly magnified. 
