GONIOCYSTIB. 349 



2. SPH^ROZOSMA EXCAVATUM, 

 Plate LXXXIV. Fig. 2. 



Char. Cells longer than broad, excavated laterally, with two 

 glands or teeth at each margin. 



Schistochilum excavatum Ralfs, MS. ; Jenner, in Flora of 

 Tunbridge Wells, p. 192. 



Hob. In a boggy spot near Cross in Hand, opposite to 

 where the road branches to Hailsham ; bogs at Fisher's 

 Castle, and in a pond between Ramslye and Broadwater 

 Forest : Mr. Jenner. 



A very distinct and interesting species. 



Section ii. 

 Frond not forming filaments . 



54. GONIOCYSTIS Hass. 



Char. Cells angular. 

 Derivation. From ywvia, an angle, and KVCTTLS, a cell. 



Section i. TRIGONOCYSTIS Hass. 



Char. Cells with three angles. 



Derivation. From rpiy&vov, triangular, and KV<TTI,S, a cell. 



1. TRIGONOCYSTIS OKBICULABIS Hass. 

 Plate LXXXIV. Fig. 7. 



Char. Frond smooth, sub orbicular. End view triangular. 

 Angles obtuse. 



Staurastrum orbiculare Meneghini, Synop. Desmid. p. 225. 

 Desmidium orbiculare Ehr., Infus. p. 141. tab. 10. fig. 9. 

 Staurastrum orbiculare Ralfs, in Annals, vol. xv. p. 152. 

 pi. x. fig. 4. a. b. c. ; Jenner, in loc. cit. p. 192. 



