Still specimens frequently occur which seem to connect the 
two. 
This species was discovered by the late Professor Mertens, on 
the coast of Holland, about the close of the last century, and first 
published by Roth, in his ‘ Catalecta.’- Mr. Dillwyn soon after- 
wards detected it near Swansea. It does not appear to be uncom- 
mon on the rocky parts of our shores, growing generally in clear 
water, and most frequently in deep pools near low-water mark. 
Seen under water it has much of the glaucous colour of C. 
Hutchinsie ; sometimes it occurs of a darker green, and then ap- 
proaches some of the less branched forms of C. rupestris, but is 
a larger and stronger growing plant. 
Fig. 1. CLapopHora DIFFUSA :—0f the natural size. 2. Part of a filament. 
3. Apex of a branchlet :—doth magnified. 
