Fresh-water Algas, &c. By A. W. Bennett. 1 3 



by its smaller size, and the very light green endochrome, with a 

 distinct vesicle in the centre of each semi-cell or frnstule. 



Tetmemorus Brebissonii Menegh. 



Zygosperm large, orbicular, olive-brown, about 1*66 times 

 diameter of frond, not inclosed in a membrane, resembling there- 

 fore that of T. granulatus rather than of T. laevis. 



Tetmemorus laevis Ktz. 



,, granulatus Breb. 

 Tetmemorus penioides n. sp. Fig. 26. 



Frond about the size of T. granulatus, 190 //, long, by 47 "5 /it 

 broad, linear-elliptic, distinctly notched at each extremity, but 

 without any lip-like process. Margin continuous, with scarcely 

 any constriction. Cell-wall not punctated or granulated. 



Among Sphagnum, Furness Fells, Lancashire, apparently 

 frequent. This species appears to form a connecting link between 

 the genera Tetmemorus and Penium. The absence of a central 

 constriction is characteristic of the latter genus, while the terminal 

 notch seems to bring it under the former. 



Fenium margaritaceum Ehrb., vars. a and 7 Ealfs. 

 „ cyhndrus Ehrb. 

 „ polymorphum Perty. 

 „ lagenaroides Eoy. (Journ. E. Micr. Soc, 188 i, 



p. 197, t. V. fig. 6). 

 „ cucurbitinum Biss. (1. c. p. 197, t. v. fig. 7). 

 „ digitus Ehrb. 



„ interruptum Breb. Park Fell. 

 „ closterioides Ealfs. 

 „ truncatum Breb. 

 „ Brebissonii Ealfs. 

 Docidium nodolosum Breb. Ambleside. 

 „ truncatum Breb. 



„ clavatum Ktz. , 



,, baculum Breb. 

 Spirotaenia condensata Breb. 



„ obscura Kalfs. Furness Fells. 



Closterium Lunula Miill. 



„ acerosum Schrank. , 



„ turgidum Ehrb. Park Fell. 



„ Ehrenbergii Menegh. 



„ Dianae Ehrb. 



„ didymotocum Corda var. /3 Ealfs. 



„ costatum Corda. 



„ striolatum Ehrb. 



