166 BRITISH DESMIDIE-E. 



ft Frond smooth, crescent-shaped, rapidly tapering from the middle. 



5. C. Ehrenbergii (Menegh.) ; frond smooth, crescent- shaped, when 

 empty colourless ; lower margin inflated at the middle ; ends 

 rounded ; vesicles numerous, scattered. 



Clostermm Lunida, Ehr. Infus. t. 5. f. xv. 2 (1838). Hassal], Brit. Fresh- 

 water At gee, t. 84. f. 4? 



Closterium Ehrenbergii, Meneghini, Synop. Desmid. in Linncea 1840, p. 232. 

 Hassall, Brit. Algae, p. 369 (excl. synonyms), t. 87. f. 1. 



Common, often in streams. Henfield, Westham, Tunbridge Wells, &c., 

 Sussex ; Chertsey and Reigate, Surrey, Mr. Jenner. Penzance and Dolgelley, 

 J. R. Bristol, Mr. Thwaites. Ambleside, Westmoreland, Mr. Sidebotham. 

 Aberdeenshire and Banffshire, Mr. P. Grant. 



Germany, Ehrenberg . Falaise, Brebisson. 



Frond bright green, stout, distinctly visible to the naked eye, lunately 

 curved, five or six times longer than broad, extremities tapering, ends rounded, 

 lower margin very concave with an inflation at the middle ; fillets several, 

 three of them more evident ; vesicles numerous, small and scattered. Empty 

 frond colourless, without a suture at the middle, collapsing when dried. 



Closterium Ehrenbergii agrees with C. Lunula and C. moniliferum in size, 

 colour and texture : it is more curved than the former, the lower margin being 

 concave, not straight, and its centre is protuberant. From the latter it differs 

 in its vesicles, which are smaller, more numerous and scattered. 



Length of frond -gL of an inch ; greatest breadth -j^-^. 



Tab. XXVIII. fig. 2. frond with endochrome. 



6. C. moniliferum (Bory) ; frond smooth, crescent-shaped, when 

 empty colourless; lower margin inflated at the middle; ends 

 rounded; vesicles in a single row. 



Lunulina monilifera, Bory, Encycl. Method. Hist. N. des Zooph. 1824, t. 3. 

 f 22, 25 and 27. 



Closterium Lunula, var., Ehr. Abh. der Berl. Ak. 1830, p. 62. 



Closterium acerosum, var., Ehr. Abh. der Berl. Ak. 1831, p. 68. 



Closterium Lunula, Kiitzing, Sgnop. Desmid. in Linncea 1833, f. 80. Bre- 

 bisson, Alg. Fal. p. 58. t. 8. 



Closterium moniliferum, Ehr. Infus. p. 90. t. 5. f. 16 (1838). Meneghini, 

 Synop. Desmid. in Linncea 1840, p. 232. BaWey, Amer. Bacil.in Amer. 

 Journ. of Science and Arts, v. 41. p. 302. t. 1. f. 31. Jenner, Ft. of 

 Tunbridge Wells, p. 196. Kiitzing, Fhy. Germ. p. 130. Hassall, 

 Brit. Alg. p. 370. 



Common. Penzance and Dolgelley, J. R. Framfield and Hastings, Sussex ; 

 and Beigate, Surrey, Mr. Jenner. Kerry, Mr. Andrews. Cheshunt, Mr. 

 Hassall. Near Bristol, Mr. Thwaites. Yate, near Bristol, Mr. Broome. 

 Aberdeenshire, Dr. Dickie and Mr. P. Grant. Banifshire, Mr. P. Grant. 

 Cheshire and Westmoreland, Mr. Sidebotham. Manchester, Mr. JVilliamson. 



Germany, Ehrenberg, Kiitzing, Corda, &c. Falaise, Brebisson. Common 

 in New York and New England, Bailey. 



