155 
During the winter months numbers of algae are washed away, 
and Colpomenia though still one of the most abundant weeds has 
rocks “ the winter gales, but the Colpomenia-thalli anenechath are 
of increased size, and thus more liable to be detached by w 
action. ot a few specimens also ‘lan detached owing sete 
imprisoned air within them rendering the thalli sufficiently buoyant 
to break away from their moorings when covered with water on the 
return of the tide. 
n the spring Colpomenia is again re. paneaneHt st, a second 
ee development has been March pril. 
Numerous Eporelings develop Doh poets and sprin 3; so that 
specimens of all ages have net found at Easter. Such plants are 
either epiphytic or saxicolou 
After April Colpomenia cis to disappear. A certain number 
of plants continue to develop during April and May, but the bulk 
of the growth is by this time of a pale yellow-brown colour, and 
much eaten by marine animals, or infested with epiphytes. A 
small number continue till June, but after this date, with the 
exception of isolated examples, the plant disappears till autumn. 
Very large specimens are to be found in May ; these usually occur 
in rock-pools in the more sheltered localities (ex .g., Studland Cliffs) 
where there is less risk of their being torn or detached by wave- 
action. The large epenany probably represent individuals which 
germinated in autumn and survived the winter, but precise infor- 
mation on this nt is not to hand, as efforts to keep individual 
plants under observation were not successful. Plants 9-10 em. in 
diameter are not at all uncommon, and the largest noted measured 
12 cm. in length. Sauvageau refers to a case at Cherbourg where 
irregular in shape, and more or less eaten and tor 
urning now to ecological considerations, the substratum to 
which Colpomenia is found attached has already been dealt with, 
and also its vertical distribution on the Bnore which is regulated. 
sheltered ground within the Portland breakwaters, it is plentiful. 
At Studland also, where the cliffs face north and the rock-pools are 
pneaery sheltered, it is very abundant, the pools from this 
region haying provided the largest specimens which have been seen. 
At Handfast Point (Old Harry pos where rougher water occurs, 
Colpomenia is not found. The effect of exposure may be 0 
also at Swanage. In the quiet ee near the pier the plant i is 
plentiful ; at. Peveril Point, where the conditions are ge it is 
almost absent, or only found between the two reefs which 
imeéasure-of shelter, In Durlston: Bay, with its shelving rocky shore 
