34 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 Ancdesea, 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 from 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 Bomney 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 fructification, 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 



