a 
part of the frond also: these are rarely indistinct, and are often very well 
defined. ‘The axils are patent, the apices spreading widely. A variety is 
common in which the lateral smaller lobes of the frond hook backwards and 
coil round any neighbouring plant. Coccidia depressed, spheroidal, generally 
marginal or in marginal processes, containing, on a central placenta, 
numerous chained spores. Spots of tetraspores minute, oblong, confined to 
a line immediately within the margin, or else placed in little leafy processes 
which fringe the principal lacinize of the frond. Suéstance delicately mem- 
branaceous, and very thin, but somewhat tough, elastic, and not adhering 
strongly to paper. Colowr a purplish or brownish full red, reflecting glau- 
cous tints when growing. 
PLO eeeerrrernn 
This is the most generally dispersed species of Mitophyllum, and 
the one most usually met with within tide marks. It frequently 
is found fringing the steep and shaded sides of deep rocky pools, 
when protected from the sun by overhanging uci; but its 
favourite place of growth seems to be on the stems of the larger 
oar-weeds. The frond varies much in breadth in different 
specimens, as may be seen by our figure, which, however, by no 
means represents the extreme forms. Some specimens are so 
broad and so little divided that they closely approach VV. Gmelini 
in aspect, especially when dried; but the substance and colour of 
the two plants are essentially different, and when seen growing it 
is impossible to mistake one for the other. A very singular 
variety of JV. /aceratum is frequently seen between tidemarks, 
attaching itself by hooked lobes to neighbouring small alge, and 
sometimes so intricately interwoven with their stems that it 
cannot be extricated without tearing. In this the frond is very 
narrow, of a brighter colour than usual, and almost every lobe 
converted into a strong recurved hook. 
I have frequently observed spores to be developed within the 
substance of the placenta, as well as on its outer surface. Our 
figure (fig. 4) represents them in both positions, as seen in a 
vertical section of the conceptacle. 
Fig. 1. NiropHyLLUM LACERATUM; a broad variety. 2. A narrow variety, 
with marginal processes :—doth of the natural size. 3. Small portion of the 
membrane with a marginal coccidium. 4. Section of the coccidium. 5. 
Marginal spot of tetraspores. 6. Marginal processes containing spots of 
tetraspores :—all magnified. 
