PROCEEDINGS OF SOCIETIES. Ill 



HISTORIC SOCIETY OF LANCASHIRE AND CHESHIRE. 



On the Diatomacece. of the Neighbourhood of Liverpool. 



By Thomas Comber, Esq. 



(Read 16tli December, 1S5S.) 



In laying before the Society the following contribution to 

 the Liverpool Flora, I have been influenced by a wish to 

 increase, in some degree, the knowledge of the Natural 

 History of the neighbourhood, towards which so much has 

 been done by other Liverpool naturalists; and although I 

 have confined myself to a single order I trust the subjoined 

 list will be of some use in this respect. I am also not without 

 hope that it will assist those whose researches have been 

 extended over a wider field than my own, in their investiga- 

 tion into the geography of the order, at present in a very 

 unsatisfactory state. 



I have adopted the limits established by Dr. Dickenson in 

 his Flora of Liverpool, extending to the north as far as 

 Southport. In this district there are found as many as. 257 

 described species of Diatomaceae, affording representatives of 

 51 genera. Of these 120 are fresh water, 64 brackish, and 

 73 marine species : these last numbers are, however, only 

 approximate, in consequence of many species being some- 

 times found in both fresh and brackish, and others in marine 

 and brackish, localities. For instance, I have gathered 

 Navicula Westii and Stauroneis sali.ua, both generally con- 

 sidered altogether marine species, in a living state in a pool 

 to which no sea water could possibly have got for at least 

 eight months. 



Those species usually found in Alpine situations, such as 

 Navicula crassinervia, N. serians, some of the Pinnularia and 

 OJontidia, Tabellaria fiocculosa, and several of the Melosira 

 and Orthosira. are absent ; but this is only what would be 

 expected: another deficiency for which I cannot account 

 occurs in the allied genera of Podosphenia, Rhipidophora and 

 Lichmophora, containing in all ten species, of which the only 

 representative found in this neighbourhood is R. Dalmatica 



I have used Professor Smith's nomenclature, as being the 

 best known, even in many instances where it is opposed to 

 my own views. Only twenty of the species, discovered since 

 the publication of the second volume of that work, are not 

 described in his synopsis. 



My best thanks are tendered to three members of the 

 Microscopic Club of this town, Messrs. G. M. Browne, 



