Clare Island Survey — Marine Algae. 15 85 



position held by Ascophyllum and F. vesiculusus, till, at \ mile below 

 Newport, the association consists entirely of this species. Ascophyllum is 

 the last to disappear, persisting on boulders, especially in the lower part. 

 At Newport Bridge, 7*1 ceranoides forms a very fine growth, of which some 

 50 or 60 yards are exposed at low-water ; as far as could be seen, it extends 

 right across the river. The association continues above the railway bridge 

 (the exact distance was not noted), where it is covered with perfectly fresh 

 water for many hours at a time. The upper part of the F. ceranoides belt 

 (at the Pelvetia level) consists of very short plants, in some cases barely an 

 inch high. Amongst it exists a certain amount of Catenella and Bostiychia, 

 especially on slabs of rock. At a lower level the growth is large and 

 vigorous, and shows as usual great blistering of the thallus. 



Bunowen. 



Rising in the mountains near Croaghpatrick, and flowing through the 

 town of Louisburgh, the Bunowen cuts a sinuous course through the boulder- 

 clay on the plain, and immerges on the sandy shore west of Old Head. The 

 banks for the last mile are loamy and steep, until about \ mile from the shore, 

 where they tend to become flatter as the river widens out. In wet weather 

 the volume of water is largely increased ; the deep brown stream being 

 perfectly fresh when the tide iS on the ebb. Many algae therefore, which 

 are normally left dry and first moistened by the returning tide, are not 

 infrequently immersed for hours in fresh water. 



Vertical Banks. — Beginning about -i- mile from the shore, we find at low- 

 water banks 3-5 feet high. Where current is felt, there is constant erosion, 

 and algae are practically absent: but in bays and bends a short vege- 

 tation exists, showing definite zonation. The sequence of the bands is 

 usually as follows, beginning at, or slightly above, the average high-water 

 level : — 



Phoeococcus adnatus, ...... 2-3 ins. high. 



Rivularia nitida, ....... 1—1^ foot „ 



Bhizoclonium riparium and Enteromorpha intestinalis var. 1 „ 



Do. with Pylaiella litoralis (F. ceranoides scattered), 1 „ „ 



This vegetation extends more or less interruptedly for some distance till 

 a bend and widening of the stream is reached. Several creeks and back- 

 waters then appear, as well as flat, muddy slopes ; and the extra shelter is 

 favourable for Vaucheria, which now becomes prominent. The average 



