DESMID FLORA OF DARTMOOR. 257 



in the plates accompanying this paper contain practically only 

 those indicated by him, and of these descriptive notes are given 

 when necessary under the heading " Description of Plates." 

 The nomenclature followed throughout in this paper is that 

 adopted by W. and G. S. West in their Monograph of the British 

 Desmidiaceae (4) as far as it is published. Unfortunately it 

 includes but a small portion of the genus Staurastrum, and for 

 the completion of the genus, and for genera such as Desmidium, 

 Sphaerozosma, etc., I have had to rely on Cooke's British Des- 

 mids (14) Kalfs's British Desmidieae (15) and whatever papers I 

 could procure supplementing these earlier works. It is for this 

 reason that the Staurastrum section of the census table must 

 be regarded as incomplete and more or less unsatisfactory. The 

 species in the census table have been arranged alphabetically 

 for convenience of reference. 



It is my pleasing duty before closing this paper to acknow- 

 ledge my indebtedness to those who have so generously given me 

 assistance in its preparation. To Professor G. S. West, M.A., 

 D.Sc, F.L.S., of Birmingham University, I am deeply indebted 

 for his kindness in going through my drawings and notes at a 

 period when he could ill spare the time, and sending me valuable 

 criticisms thereon. Several members of the Quekett Micro- 

 scopical Club have been extremely generous with their help : 

 Mr. C. Turner and Mr. J. Wilson have kindly and patiently gone 

 over gatherings of nearly all the principal bogs I have collected 

 from, sending me lists whereby I have corroborated and extended 

 my own ; to Mr. C. D. Soar, F.L.S., and Mr. D. J. Scourfield, 

 F.Z.S., and also to Mr. C. H. J. Sidwell, F.R.M.S., I owe thanks 

 for lending me literature connected with the group that has been 

 invaluable. Finally, I would ask The Quekett Microscopical 

 Club to accept my thanks for the kindness it shows me in accept - 

 ing this paper for the pages of its Journal. 



Special Notes on Some Species 



(5) Gonatozygon filosum Wolle. This rare species appears to 

 be confined on Dartmoor to the old and prolific bogs of 

 Metherall, Gidleigh and Postbridge. It rarely occurs. 



