vous short pedate lobes, which overlap each other; in others the seg- 
ments are split nearly to their base into linear-wedge-form ribbons, from 
a quarter to half an inch in length. The uninjured apices are always ob- 
tuse. In fertile specimens the lateral margins of the lobes, especially 
towards the base, are minutely curled and closely fringed with minute, 
leafy, subsimple, or multifid processes, in which the tubercles are formed. 
Tubercles variable in size, globose, always formed in the marginal cilie, 
containing several detached groups of spores; spores hyaline, each con- 
taming several coloured grains. Tetraspores forming cloudy patches, not very 
obvious, arranged along the margin of the frond, tripartite, or occasionally 
cruciate. Frond composed of very minute cells, arranged in a somewhat 
fibrous manner, traversed by numerous empty spaces or lacuna. Substance 
thickish, somewhat cartilaginous. Colour a beautiful, clear, bright red, 
varying to crimson or blood colour, and well preserved in drying. 
ae 
a ao nn aa 
This species is subject to very considerable variation in form, in 
size, and in the relative proportion of its different parts, and yet 
there is so much that is common to every variety, that it is rarely 
mistaken for anything else, although in the earlier days of marine 
botany, its synonymy was very much confused. ‘The modern 
division into genera has certainly facilitated in this stance, the 
recognition of species, and there is now no need to contrast the 
characters of this Alga with those of Mitophyllum laceratum, as 
was necessary at the time when Mr. Turner commenced his labours. 
The difference in the structure of the frond and in the fructifica- 
tion, are so marked and obvious that no commonly attentive 
person can now confound these two plants. 
The structure of the frond im Rhodymenia laciniata is consi- 
derably different from that of the typical species, and at a future 
time, it may become the type, as already proposed by Kiitzing, 
of a new group, to which, probably, several exotic species may 
belong. The large empty spaces, or lacunee, with which the 
substance is permeated, which do not appear to be enlarged 
cells, but rather cavities, are not found in true Rhodymenie ; 
and it is these, seen through the surface cellules, which give the 
appearance of areolation, noticed by Mr. Turner, when the plant 
is examined with a pocket lens, and which is lost if the frond be 
subjected to a higher magnifier. 
Fig. RHopDYMENIA LACINIATA:—of the natural size. 2. Tubercles of the 
ordinary kind. 3. Tubercles of larger size, occurring on plants which are 
imperfectly ciliate. 4. Section of a tubercle and of the frond. 5. Spores. 
6. Part of a sorus of ¢etraspores. 7. Tetraspores:—all more or less mag- 
nified. 
