pellucid, those of the main branches four or five times longer than broad ; 
of the upper branches gradually shorter ; of the ramuli exceedingly short ; 
all deeply coloured at the swollen joints. Zetraspores immersed in the 
joint, several in each, disposed in a whorl. avelle surrounded by an 
involucre of several (4-5) short incurved ramuli, either sessile in the upper 
forks or borne on lateral peduncles. Substance soft, but rather firm ; glossy 
when dry, and adhering pretty firmly to paper. Colour, a brownish-red, 
with a purplish tinge ; sometimes more clearly purple. 
———_—s 
Our figure is intended to represent the ¢ypical form of the old 
Conferva diaphana of British authors, the longest known of the 
extensive group of the genus to which it belongs; a group 
which contains numerous very distinct plants, which were once 
confounded together as varieties of the species now under review. 
From the British species of this section, except one, our C. dia- 
phanum may be at once known by its larger size and more robust 
filaments ; it is also well characterized by the lateral dichotomous 
ramuli given off all along the principal divisions of the frond, 
and by the gradually attenuated filaments. These last characters 
distinguish it from C. nodosum and C. fastigiatum. 
Limited as it now is, the species has a very wide range, being 
found in most of the temperate parts of the sea. Though existing 
on all our coasts, from north to south, it does not appear to be 
very abundant anywhere, seldom growing in society: the tufts 
being thinly scattered here and there through the rock-pools. 
When growing, few Algze are more delicately beautiful ; and even 
in a dry state it forms a very handsome object, the brilliancy and 
regularity of the dot-like joints, connected by hyaline, oad 
spaces, having the effect of a piece of fine tracery. 
Fig. 1. CeramiuM DIAPHANUM :—of the natural size. 2. Branch, with tetra- 
spores. 3. Joints from the same. 4. A tetraspore. 5. Branch with 
favelle. 6. Joints from the same, with involucrated favelle :—all more or 
less highly magnified. 
