(88) 



and scattered, occasionally more or less collected in groups ; enclosed in 

 a narrow pellucid limbus. 



This rather pretty and delicate Alga is everywhere met with on all 

 our shores, generally gTOwing on rocks and stones, and occasionally on 

 other Algse in the deeper tide-pools, where its long, soft, conferva-like 

 bundles form a very conspicuous object during spring and summer 

 months. The extreme delicacy of its filaments, and the abundant 

 branching, give a softness and a woolliness to the entire aspect of the 

 plant, scarcely observed in auy other species. In spring and early 

 summer, when the plant is yet covered with the thin transparent robes 

 of its early youth, so soft and delicate is the mass, that when lifted out 

 of the water it retains so much of the fluid, that it looks almost like a 

 mass of dark fibrous jelly, and when squeezed in the hand it pours out 

 the water like a sponge. 



We are informed in Phyc. Brit, that Areschoug considers this merely 

 a state of Chordaria Jlagelliformis without the coating of radiating 

 filaments that form the periphery in that species, having found branches 

 with both kinds of structure on the same plant, and a suggestion is 

 there offered that we may have more than one species confounded under 

 the present. The Dktyosiplion is very commonly parasitical on Chor- 

 daria. Coxild it be possible that the great Swedish naturalist could 

 have mistaken such a circumstance and been deceived by two branches 

 thus occurring together or even attached 1 a young plant, for instance, 

 of Dictyosiplion attached to the Chordaria might very readily be mistaken 

 for parts of the same plant. We have been often very much puzzled 

 with them under such circumstances. 



The present species has considerable resemblance to Desmarestia viridis, 

 and may readily be mistaken for it, but the invariably opposite branches 

 in that species, and the articidated upj)er ramuli, will always serve to 

 distingu-ish them. 



Dr. Harvey also mentions having specimens collected on the west 

 coast of Ireland, in which the fruit is collected in clusters, as in Striaria, 

 but not disposed in transverse bands, and that such specimens exhibited 

 also a somewhat different habit from ordinary ones. 



EXPLANATION OF PLATE CLXL 



Fig. 1. — Dictyosij)hon fcenicidaceiis, natural size. 

 2. — Longitudinal section of old branch. 

 3. — Transverse section of same. 

 4. — Longitudinal section of young branch and spores. 

 5. — Transverse section of young branch. 

 6. — Spores. 

 7. — Apex of a branch. All magnified. 



