GONIOCYSTIS. 349 



2. SPHiEROZOSMA EXCAVATUM, 



Plate LXXXiy. 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. 



Hab. 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 fyoivia, an angle, and KvcrTi9, a cell. 



Section i. Trigonocystis Hass. 



Char. Cells loith three angles. 



Derivation. From rpiycovov, triangular, and Kvaris, a cell. 



1. Trigonocystis orbicularis Hass. 



Plate LXXXIV. Fig. 7. 



Char. Frond smooth, suborbicular. 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. 



