VI BRITISH DESMIDIACE^E. 



of British Freshwater Algse ' was published by Hassall, 

 and in this work (58 Desmids were described and 

 figured. Hassall did not give the dimensions of the 

 species, and both the text and figures are often very 

 inaccurate. Three vears later, in 184-8. Ralfs' ' British 



t 



Desmidiea? ' appeared, and this book undoubtedly 

 opened the eyes of British naturalists to the wondrous 

 beauty of a neglected class of plants. At the same 

 time it gave a stimulus to the study of microscopical 

 botanv, and Ralfs' book stands to-dav as the only 



. J t * 



monograph extant containing accurate figures of these 

 simple plants. In this classical volume Ralfs described 

 and figured 162 species and 32 varieties of British 

 Desmids, and 18 species and 4 varieties of other 

 Alga3 belonging to the genera Ankistrodesmus, Pe<Ji<i*- 

 triiiu, and Scenedesmus. These genera were at that 

 time supposed to belong to the Desmidiaceae. He also 

 briefly included some 64 species of Desmids and '} 

 species of other Alga3 which had been found in 

 foreign countries. 



From 1858 to 1885 a large series of notes and short 

 papers by W. Archer appeared in the ' Proceedings of 

 the Dublin Microscopical Society ' and the ' Quarterly 

 Journal of Microscopical Science,' and in 1861 the 

 same writer contributed the article on the Desmidiacese 

 for Pritchard's 'Infusoria.' These are unquestionably 

 among the most valuable contributions to the literature 

 of British Desmids, and clearly prove that Archer 

 \vas second to none in his detailed acquaintance and 

 clear insight into the structure and habits of these 

 plants. It is a great pity that many of his preliminary 

 notes were never followed by his promised detailed 

 descriptions and figures, as in several instances they 

 were too meagre to be of any value. 



