S34 NATURAL SCIENCE [July 
and Sandgate has been explored by Mr J. Cosmo Melvill and 
myself, but the rest of the coast is, I believe, entirely unexplored. 
Only about 110 species out of more than 750 British species have 
as yet been found in the county, although at least 500 of the British 
species might reasonably be expected to occur. The richest places 
are, as a rule, muddy estuaries, the open sea where streamlets run 
into it, Zostera beds, and rocks exposed at low water. Also places 
where two tides meet, as at Whitstable. The shells dredged by 
fishermen often have deep-water species attached to them. 
The limit of the northern species on the east coast of England 
still needs accurate determination, one of these, Monostroma Blyttii, 
having been found as far south as Deal. On the western coast 
several of these have been traced as far south as Anglesea, but on 
the eastern coast, where the influence of the Gulf Stream is far less 
felt, they might be expected to extend further south, and the coast 
of Kent might furnish important data on this point. 
That this group of plants affords an excellent field for work is, 
I think, evident froin the fact that a small band of British algolo- 
gists, less than half a dozen in number, have succeeded in nearly 
doubling the number of British species known in 1851, raising 
them from 400 to about 750 in 1898. This has been done, chiefly, 
by searching for the species known on the adjacent shores of 
Norway and France, but not in England. The majority of these 
have been found in England and Scotland, but several deep-water 
species yet remain to be discovered. 
6. Fresh Water Algae.—A few local lists of fresh-water 
algae, including diatoms and desmids, have been published, but 
these only furnish a very small proportion of the possible number 
of species that should occur in Kent. The best localities for search 
are the brackish and fresh-water marsh ditches from Gravesend to 
Pegwell Bay, and those around Minster near Canterbury, also the 
ponds and ditches of the Weald and Gault, and the springs issuing 
from the Chalk hills. The military canal near Hythe and the 
ditches in Romney Marsh should afford many species. Spring and 
autumn are, as a rule, the best time to collect them. In summer 
the growth of aquatic plants is often so luxuriant that many species 
are hidden. : 
It is necessary also for the collector to remember that many 
species, such as Spirogyra, which are not easily determined except 
when in fruetification, often assume, when in that state, a yellowish 
tint that would suggest decay and perhaps prevent their collection. 
Hitherto I have spoken only of the work to be done in the 
county of Kent, but much of the same kind of work requires to be 
done in the other three counties. 
I may perhaps take this opportunity to direct attention to 
