68 ON PROTOPLASMIC CONTINUITY IN THE FLORIDEZ. 
in shape and appearance, small multi ane nerve-cells, 
threads and bodies is formed. The connecting rege are much ~ 
finer si most of those previously described, but s of them © 
carry a small bright particle which may be isco to: represent — 
the eoilar met with in other genera. 
igartina mamillosa, in its external characters, er es many — 
oints of resemblance to Chondrus crispus, an veges 
structure is also more or less similar. The sale of the } 
portions of the frond are however more regularly filamentous, vend | 
have fewer protoplasmic connections with other cells. Where they — 
form filaments, the cells are connec a longitudinally by single © 
protoplasmic threads, similar to those of the less complex i 
thamnions so that each cell has only rata connections, except where, — 
a branch is given off, in which case there are three. . 
Plate 244, figs, 12 and 18, are semi-diagrammatic views of the — 
ae and Gigartina respectively, wick will illustrate these — 
t 
cellular elements, The pro anit connections of the former are ~ 
noteworthy, as yrsaeastity appearances not unlike those of the ~ 
smaller sieve tubes of the cucumber and veicat malrow. : 
. Procamium. 
The genus Abin is oo on British coasts by a — 
single species — viz., P. cocci St is a well-known ~ 
“weed,” and consists of mpre poieeil'm mbranaceous frond, 
whose gliimaes "aushight -s cpimmnte ne alternately secund. — 
Each portion of the frond is composed of an axial row of cells, — 
which becomes densely corticated and only remains free, if any- — 
where, at the tips of the ultimate ramification 
Sections made in different directions alee: the stouter portions a 
of the frond reveal a very elaborate system of .protoplasmic — 
h 
pas ugh the end wall h hey 0 
ae r urrounding the axial cells is a layer of moderately 
e, polyhedral er whose walls, like 
it ; 
protoplasm, and in the older parts may differentiate a delicate : 
membrane similar to that described in Polysiphonia fastigiata. 
