cells of the superficial layer (or epidermis) being short and either square or 

 polygonal. Spores scattered freely over the branches. (On some indivi- 

 duals I have observed aggregated spores, forming scattered clusters or sori.) 

 Colour a pale olivaceous, becoming darker in age and on being dried. 

 Substance membranaceous and soft, closely adhering to paper in drying. 



A common inhabitant of tide-pools, and not inelegant, espe- 

 cially when clothed with the fine soft hairs which cover its 

 surface closely, when in a young and vigorous state, before it has 

 suffered from the wear and tear of its short existence. 



I believe by most British algologists this plant is regarded as 

 sui generis, entitled to a clear place in our system of arrange- 

 ment, and properly referred to the Dictyotece. But a distin- 

 guished Swede, Areschoug, regards it unhesitatingly as an abnor- 

 mal state of Chordaria fay ell if or mis, in which the horizontal fila- 

 ments of the periphery have not been developed, and he states 

 that he has found specimens having some of the branches with 

 the structure of Chordaria, and some with that of Dictyosiphon. 

 This is, a subject worth examining, but requiring a very careful 

 and accurate observation. 



It is also possible that we have two species, or perhaps more, 

 confounded under this name. I possess specimens collected on 

 the west of Ireland some years ago, having rather a different 

 habit from ordinary forms, and differing in having their spores 

 collected in clusters, as in Striaria, but not disposed in trans- 

 verse bands. To these I once gave the MS. name of B.frayilis, 

 which is adopted by Kiitzing, in his recent ' Systema Algarum.' I 

 have deferred noticing these specimens hitherto, from an un- 

 willingness to multiply doubtful species. 



Fig. 1. Dictyosiphon fo^niculaceus •. — the natural size. 2. Portion of a 

 branch: — slightly magnified. 3. Small part of the same, with, fruit and 

 some hairs. 4. Longitudinal section of the stem. 5. Transverse section 

 of a young branch. 6. The same, of an older branch, now become hollow : 

 — all highly magnified. 



