214 SUMMARY OF CURRENT RESEARCHES RELATING TO 



supply in standing pools of sea-water ; (2) competition for substratum 

 of green intrusive algse ; (3) the greater success of the associated 

 organisms in subaerial conditions ; (4) the nitrogen problem keeping the 

 plants impoverished ; and (5) the water problem restricting their growth 

 to shorter seasonal periods. A. L. S. 



New Portuguese Lichens. — Gonqalo Sampaio {Ami. Acad. Foly- 

 technica do Porto, 1917, 12, 1-4). Diagnoses of seven new species of 

 crustaceous lichens. A. L. S. 



The Sulphur Lichens of Saxon Switzerland. — A. Sghade {Ahh. 

 Naturio. Ges. " Isis'" Dresden, 1916, 28-44; see also J^ww. Mycol., 1917, 

 15, 511). The yellow colour of the Sandstone rocks, due to the colour 

 of the vegetation, has been determined by the author as caused by the 

 growth chiefly of Lepraria chlorina, to a lesser extent by Biatora lucida 

 and others. A. L. S. 



Lichens of Sardinia, — Giuseppe Colosi {Malpighta, 1919, 28, 

 458-71). The lichens here listed were collected by the author during 

 a stay at Cagliari. He gives a list of the places visited. He has added 

 two new varieties to science — Ramalina capitatavar.sardoasiTid Parmelia 

 tiliacese var. alba, so designated from the white under-surface. A. L. S. 



NOTICES OF NEW BOOKS. 



Critical Microscopy : How to get the Best out of the Microscope. 

 By Alfred C. Coles, M.D., D.Sc, M.E.G.P., F.R.S.E. 1921. 

 viii + 100 pp. and 3 pis. Published by J. and A. Churchill, 

 7 Great Marlborough Street, W.l, Price 7s. Qd. net. 



Faune de France : L Echinodermes. By Professor E. Koehler. 1921. 

 210 pp. and 153 figs. Published by Paul Lechevalier, 12 Rue 

 de Tournon, Paris. Price 25 francs. 



Faune de France : IL Oiseaux. By P. Paris. 1921. 474 pp. and 

 490 figs. Published by Paul Lechevalier, 12 Rue de Tournon, 

 Paris. Price 40 francs. 



Supplement (1918-1920) to the Catalogue of Lewis's Medical and 

 Scientific Circulating Library, with List of Additions to 

 March 1921. 68 pp. Price Is. net. 



Dictionary of British Scientific Instruments. Issued by the British 

 Optical Instrument Manufacturers' Association. 1921. xii + 

 334 pp. Published by Constable and Co., Ltd., London. 

 Price 21s. 



