dotted, or clothed with a tessellated membrane. A transverse section
(fix-. 4 .), exhibits a n a n w central tube, surrounded by several rows of
hexagonal ceUs, each of which contains a coloui-ed bag ; a longitudinal section
(fig 5 .), shows that the central tube is jointed at mtervals of four to
five times its breadth, and that the cells that encompass it become gradually
shorter towards the circumference. T h e /re it (which I have not seen) con-
sists of ceramidia, which have only been noticed by Koth, by whom they
are very imperfectly described ; and stichidia, or lanceolate pods, terminating
the branches, and containing triparted tetraspores. Co/oMr purplish,
brownish or greenish, according to l o c a l i t y Substance cai-tilaginous, imperfectly
adhering to paper in drying.
In the year 1838, Dr. Montagne, in the botanical portion of
M. de la Sagra’s history of Cuba, established his genus Bostry-
cUa upon B. scorpioides, and a tropical species, B. calamistrata,
with which he has since associated several others, having similar
organization; and I wish now to extend the generic character,
so as to comprise a little group of southern species, to which I
have elsewhere apphed the name Stictosiplionia, which differ
from the type, in having their central tube surrounded by a
single row of coloured cells. The genus thus constituted consists
of ten species, all of which have a similar habit, and all are
found in situations either bordering on high-water mark, or in
places where a considerable quantity of fresh water flows into
the sea. In this respect they differ from most other Bliodo-
melem, a tribe of Algse the majority of which grow at a considerable
depth, and are peculiarly impatient of the contact of
fresh water. So little is this the case with our B. scorpioides
that it has been called amphibia, from its sometimes growing in
ditches of brackish water, and such also, according to Dr.
Hooker, are the situations chosen by B. vaga, at Kerguelen’s
Land.
The name Melicothamnion, proposed by Kiitzing for B. scorpioides,
must be laid aside, as that of Bostrychia has the priority,
is equally applicable, and more euphonious. By Prof. J. Agardh
this group is included in Alsidium, hut it scarcely agrees with the
character of that genus, and still less with the habits of its species.
.Fig. 1. B o s tk y c h I -A s c o k p i o i d e s , a tuft :— of the natural size. 3. Part of a
b ra n c h . 3. In v o lu te a p e x o f th e ram i, w ith a p o r tio n o f a la te r a l b ra n c h le t.
4. Transverse section of a branch. 5. Longitudinal section oi the same :
— all more or It