15 178 Proceedings of the Royal Irish Academy. 



6. C. mucronatum var. Novae Zelandiae. Note similarity of utricles to those 



of the Irish plant. (New Zealand, Herb. Kew.) 



7. C. mucronatum var. tasmanicum. Apex of utricle very pointed. 



(Tasmania, Herb. Kew.) 



8. C. mucronatum var. califomicum. Mucro long, blunt ; often apparently 



articulate. (California, Herb. Kew.) 



Plate IX. 

 Ptilothamnion lucifugum sp. nov. 



1. Decumbent and upright fronds, showing irregularly produced branches 



and pinnae, (x c. 15.) 



2. Part of a branch showing pinnae and forked pinnulae. The pinnae are 



occasionally opposite ; but usually the opposite pinna remains 

 practically undeveloped, (x 80.) 



3. End of pinna, (x 140.) 



4. Pinnulae with antheridia. (x 140.) 



5-6. Part of decumbent branch showing rhizoidal pinnae, which occasionally 

 terminate in a more or less discoid expansion, (x 140.) 



Plate X. 

 1-2. Calothrix endophytica sp. nov. 



I. Portion of Enteromorpha frond showing Calothrix filaments within the 



cavity, (x 400.) 2. Cluster of short filaments, with the basal 



heterocysts (normal), (x 500.) 3. Longer filaments, with basal and 



intercalary heterocysts. (x 500.) 



4-9. Ascocyclus Saccharinae sp. nov. 

 4. Discoid thallus, easily separable into filaments. 5. Assimilating 



filaments and young aseocysts. 6. Assimilating filaments and 



young sporangia. 7. Sporangia and hairs, with basal sheath. 



8. Sporangia, and two empty aseocysts. 9. Two aseocysts with 



contracted contents, (x 400.) 

 10. Nitoph.yllum uuciuatum J. Ag., showing irregular fronds and acuminate 



branches. (Dried specimen, nat. size.) 



II. N. laceratum var. uuciuatum Grev. Quite distinct from the last, being 



merely a variety with uncinate branches of the common N. laceratum 

 (nat. size). 



Plate XI. 



Map of the Clare Island District. 



