RHODOSPERME. 131 
within the margin. A vertical cutting of one of the tubercles or coccidia 
of this species, very highly magnified, is represented at c. Fig. 117. 
The spores are developed in the terminal cells of the branched threads 
which arise from a placenta, or basal projection, in the centre of the 
tubercle. The arrangement of the spore-threads and production of the 
spores at their tips, is very similar in the coccidia of the Delesseriw, but the 
form is a little different. The tubercles in the Nitophylla are usually 
longer than high, when viewed as represented in Fig. 117; but in the 
Delesserie they are more generally spherical, and the spore-threads are set 
more upright and closer together. N. laceratum (Fig. 120) is one of the most 
abundant of the genus. It grows underthe shelter of the larger alge, and is 
often found attached to Corallina officinalis (Fig. 111) in rock poolsabout half- 
Fig. 119. Nitophyllum Hillie. 
tide level. In form and size it is very variable, deep-water specimens only 
being of large size, and broad in the segments of the frond; theseare generally 
found on the stems of Laminaria digitata (Fig. 46). In shallow pools this 
species rarely exceeds 6in., but I have gathered specimens on the shore at 
Exmouth and near Plymouth that would easily have covered a folio page. 
Fig. 120 was taken from one of my Exmouth plants, the fronds of which 
were 12in. long. This species, when viewed in clear rock pools under 
the influence of sunlight, is beautifully iridescent. The fronds are 
dichotomous, or branched by repeated forkings ; the margins are sometimes 
smooth and even, but more frequently waved and notched, and occasionally 
the long segments are twisted or curled, and very much interwoven. 
Some specimens are fringed with little ciliated or narrow leafy processes, 
nN 2 
