20 KRITISH 



collected to last many years. The Desmids offer a 

 wide field for investigation, as many parts of the 

 British Isles have not yet been examined. We have 

 made many long journeys for years past specially for 

 collecting these plants and other Algae amongst which 

 they are found, collecting daily through long holidavs, 

 but it is impossible for us unaided to cover the whole 

 of the British Isles. We have been kindly helped in a 

 few instances by material collected for us by friends 

 in places which we have not ourselves visited. We 

 have collected in Cumberland, Westmoreland, Durham, 

 Yorkshire, Lancashire, Derbyshire, Lincolnshire, Cam- 

 bridgeshire, Essex, Middlesex, Surrey, Sussex, Hamp- 

 shire, Devonshire, Cornwall, the Scilly Isles ; Anglesey, 

 Carnarvonshire ; Dumfriesshire, Kirkcudbrightshire, 

 Wigtownshire, Ayrshire, Dumbartonshire, Perthshire, 

 Argyllshire, Aberdeenshire, Inverness, Ross, Suther- 

 land, Caithness, Isle of Skye, Lewis, Harris, North Uist, 

 Benbecula, South Uist, the Orkney Isles, the Shetland 

 Isles; Antrim, Londonderry, Donegal, Tyrone, Armagh, 

 Down, Louth, Wicklow, Mayo, Galway, and Kerry. 

 Archer also collected in Dublin, Wicklow, Gralway, and' 

 Kerry, and was the pioneer in the investigation of the 

 fresh- water Algas of Ireland especially of the Des- 

 mids. Roy collected from several Scottish counties 

 and worked up material sent to him from other parts 

 of Scotland. He also made some collections in Wales 

 and examined a collection sent to him from Hampshire 

 as well as material sent to him from Leicestershire. 

 Ralfs did a good deal of work in West Cornwall and 

 also collected at Dolgelly. Marquand added to the 

 work done by Ralfs in West Cornwall. Jenner also 

 collected good material in Sussex and Kent. This 

 enumeration of counties shows clearly that a large part 

 of the British Isles is yet un worked, and many of the 

 counties enumerated have not been examined in a 

 detailed manner. It is most desirable that much more 

 work should be done in order to make our knowledge 

 of the distribution of the Desmids more complete. 





