PREFATORY NOTE. 
THe rearrangement of the British Lichens in the Herbarium of the 
British Museum and the incorporation of a Brea series of specimens 
made a revised Catalogue of these plants a necessity. 
The large number of authentic specimens from Dillenius, Hudson, 
Sowerby, Dawson Turner, T. Taylor, Salwey, Mudd, and Leighton 
contained in the Herbarium supplied material for determining the 
suaies of these lichenologists which does not exist elsewhere ; while 
the extensive series of British Lichens, including the collections of 
Buddle, E. Forster, R. Brown, Carroll, Piggot, Holl, Crombie, and 
Larbalestier, made it possible to determine with certainty the 
geographical distribution of the species within the British Islands. 
The Rev. J. M. Crombie, M.A., undertook the preparation of a 
Monograph based on these materials. This volume contains descrip- 
tions of half the known British species. The remainder (consisting 
of the Lecideei, Graphidei, Pyrenocarpei, Peridiei, and Myriangiacci) 
is so advanced that it may be expected to appear in 1895, and 
will contain a complete index to the genera and species of the 
whole work. 
WILLIAM CARRUTHERS. 
March 184. 
