444 Proceedings of the Roi/al Irish Academy. 



"We have attempted to save space by the following abbrevia- 

 tions : — 



T. = W. Thompson. D. = Doran. 



M. = Dr. D. Moore. C. = I. Carroll. 



Mc. = McCalla. B. = Miss A. Ball. 



H. = "W. H. Harvey. N. = Authors of Paper. 



PH^OPHTCE^. 



Cohort I. ECTOCAEPIN^. 



Order i. — Desmaeestiace^. 



Desmarestia, Lamx. 



This genus is very commonly represented on all the Irish 

 coasts by the first three species. The th alius provides good 

 material for the observation of trichothallic growth. 

 J), virtdts, Lamx. 



Unilocular sporangia are described in Crouan's " Florule 

 du Finistere." Occurs on all the coasts. ^ 

 D. aculeata, Lamx. 



Xuckuck (2) describes the unilocular sporangia in the winter 

 state of this species. On all the coasts, one of the commonest 

 species. 

 D. ligulata, Lamx. 



One of us (non fig. 14 in Annals of Botany, v., pi. viii.) 

 described the unilocular sporangia; both extra and intcr- 

 tidal, on all the coasts. 

 B. Budresnayi, Lamx. 12. 



This is not uncommon on the coast of France, and has been 

 recently dredged by Brebner at Plymouth. It is quite rare in 

 Ireland. There is a specimen in Trinity College Herbarium, 

 collected by G. Sanders in Lough Foyle. One of us, working 

 at Inishbofin, Connemara, in August, obtained a specimen of 

 this plant by dredging in 13 fathoms off the Gunn rock. 



Order II. — Dicttosiphonace^. 

 Dictyosiplion, Grev. 



The branch-tips are unjointed and cortexed. 

 D. fceniculaceus, Grev. 



This species, common like Desmarestia viridis, is distinguished 

 from it by having its branches usually alternating. Pluri- 

 locular sporangia are unknown. Occurs on all the coasts. 



