ZYGNEMA. 151 



Rackham, near Piilborougli : Mr. Jenner. Dolgellcy : 

 Mr. Ralfs. Parkind : Major Martin. 



This is a very distinct, as well as common species ; that 

 which I regard as a variety of it occurs at Wanstead Fhits, 

 Essex, in which the filaments are somewhat finer, the cells 

 considerably longer, and the sporangia smaller. This may 

 be distinct. 



24. Zygnema longatum Hass. 

 Plate XXXI. Figs. 3, 4. 



Char. Filaments about equal in diameter to those of Z. sub- 

 ventricosum. Cells usually eight times as long as broad. 

 Sporangia not producing any inflation of the cells, in 

 ichich they are formed. 



Conferva punctalis Miiller, Flor. Dan. pi. 1. no. 1. Con- 

 jugata longata Yaucher, Hist, des Conf. pp. 71, 72. 

 plate 6. fig. 1.; Dillw. t. 3. upper figure in part? Z. 

 cBquale Hassall, in Annals of Nat. Hist. vol. x. p. 39. 



Hab. Cheshunt, rare : A. H, H. In a pond between 

 Pembury and Lamberhurst Quarter : Mr. Jenner. 



I have but little doubt of the correctness of the synonymes 

 quoted ; the cells are never inflated. " II n'y a rien de plus 

 elegant et de plus gracieux au microscope que cette jolie 

 conjuguee." — Vaucher. 



25. Zygnema inflatum Hass. 



Plate XXXII. Figs. 6, 7, and 8. 



Char. Filaments of much less diameter than those of Z. sub- 

 ventricosum. Cells usually four, Jive, or six times as long 

 as broad. Sporangia elongated, and lodged in cells which 

 become considerably inflated for their reception. 



Conjugata injiata Vaucher, Hist, des Conf. p. 68. plate 5. 



fig. 3. Zygnema varians Hassall, in Annals of Nat. Hist. 



vol. xi. p. 431. 



L 4 



