104 BRITISH DESMIDIACEJE. 



inflated in the middle, gradually tapering though still 

 thick towards the apices, which are blunt and rounded ; 

 membrane- smooth and colourless. Endochrome a 

 single longitudinal band, not plicated, each locellus 

 containing a single moving granule, forming a rounded 

 cavity in the plasma, at some distance from the 

 apex." 



TIM-: LAND.- -Dublin and "Wicklow (Arrlirr). 



The above is the only description ever published of this 

 ('loxIm'iDii, ;m<l the size was not stated. We have not seen 

 any Desmid in the genus which could bo referred to it. 



41. Closterium praelongum Breb. 

 (PI. XXI, figs. 1, 2.) 



Closterium pr.rlongum Breb. Listo Desm. 1850,, p. 152, t. 2, f . 41 ; Arch, in 

 Pritch. Infus. 1861, p. 717 ; Kabenh. Flor. Europ. Algar. Ill, 1S6S, 

 p. 130 ; Cooko, Brit. Dcsm. 1886, p. 22, t. 10, f. 2 ; Wolle, Freshw. Alg. 

 U.S. 1887, p. 24, t. 55, f. 15, 16; De Toni, Syll. Alg. 1889, p. 8W; Hoy & 

 Biss. Scott. Desm. 1S94, p. 247 ; Nordst. Index Dosni. 1896, p. 205 ; West 

 & G. S. West, Alg. S. England, 1897, p. 480 ; Alga-fl. Yorks. 1900, p. 54. 



Arthrodia prxlonga K/untze, Eevis. gen. plant. 1891, p. 884. 



Cells of medium size, very elongate, 30-45 times 

 longer than their diameter, slightly curved, outer 

 margin about 25 C -30 of arc, inner margin slightlv 



O O O / 



concave, not tumid, gradually attenuated towards the 

 extremities which are a little recurved, apices obtuse 

 or rounded-truncate ; cell-wall smooth and colourless ; 

 chloroplasts with one series of 10 or 12 pyrenoids; 

 terminal vacuoles with many moving granules. 



Zygospore unknown. 



Length 530-840 ^; breadth 11-5-24 /x. 



ENGLAND. Lough rigg, and near Bowness, West- 

 moreland ! Malham Tarn Bog and Boston Spa, AY. 

 Yorks! Riccall Common, E. Yorks! Near Chapel Wood, 

 S.E. Surrey ! 



WALES. Capel Curig, Carnarvonshire ! 



SCOTLAND. Moss of Logie in Cromar, Aberdeen ; 

 Scolty Dam near Banchory, Kincardine (Hoy fyBissett}. 



IRELAND. - - Near Leenane, Galway ! Dublin and 

 AYicklow (Archer). 



