112 TEANSACTIONS LIVEEPOOL BIOLOGICAL SOCIETY. 



G. setacea, C. Ag. 



I. of Man !, Hilbre I. !, Puffin I. !, New Brighton. 

 Halurus equisetifolius, Kiitz. 



(Grijfithsia equisetifolia, Keport I.) 



North Wales (fide Ealfs). 



Tribe III. — Monosporese. 

 Monospora pedicellata, Solier. 



Hilbre I.!, Puffin I.! 

 Pleonosporium borreri, Nag. 



I. of Man, Hilbre I., New Brighton. 

 Tribe IV. — Callithamniese. 

 Rhodochorton rothii, Nag. 



Puffin I.!, Anglesea!, Hilbre I.!, I. of Man! 

 Mersey. 

 B. florididum, Nag. 



Puffin I. !, Hilbre I. !, Anglesea !, I. of Man ! 

 B. membranaceum, Magn. 



Puffin I. !, Hilbre I. !, I. of Man ! 

 B. seiriolanum, Gib. 



This species of Bhodochorton I have ventured to record 

 as new to science.* In character it seems intermediate 

 between the genera Callitliamnion and Bhodochorton. The 

 erect filaments are unbranched and spring from a mem- 

 branous disc. The tetrasporangia are borne secundately 

 near the apex of the filaments, the oldest near the 

 apex. The species is a very minute one, the filaments 

 being on an average less than 1 mm. long. I found it as an 

 epiphyte on the main stems of Polysiphonia urceolata var. 

 patens, in the Beacon Channel, West Spit, Puffin I. In 

 the same paper (I.e.) I described the mode of formation of 

 sporangia in the genus Bhodochorton by a process of in- 

 novation, a phenomenon which has been observed in 



Mour. Linn. Soc. Bot. Vol. part 33. 



