9 
Freshwater Alyse and Schizopliyceee. By A. W. Bennett. 
Penium cylindrus Breb. 
„ digitus Breb. 
,, navicula Breb. 
A widely distributed species ; probably often overlooked from its 
remarkable resemblance in form to a Navicula. 
Penium closterioides Blfs. 
„ Brebissonii Rifs. 
„ didymocarpum Lund. 
Cylindrocystis diplospora Lund. 
„ crassa DBy. 
*Mesotfenium chlamydosporum DBy. 
Only mentioned in Cooke as occurring in Ireland. 
* Mesotaenium De Greyi f Turn. 
Punchbowl ; length about 80 /x. 
Tetmemorus Brebissonii Rifs. 
„ granulatus Rifs. 
,, levis Rifs. 
„ penioides Benn. 
*Tetmemorus minutus DBy., Conj., p. 74, t. v. f. 10. (Figs. 
8, 9.) 
Length 45-50 /x, breadth 15-18 /x ; narrowing rather rapidly at 
the extremities ; constriction and terminal lobing both inconspicuous ; 
membrane quite smooth ; endochrome granular, with central row of 
vesicles. Resembling T. levis, but about two-thirds its length, and 
broader in proportion. Punchbowl, Hindhead. Hitherto recorded 
from the Black Forest, Silesia, Bohemia, Finland, and the United 
States. 
Spirotaenia condensata Breb. 
„ obscura Rifs. 
Micrasterias denticulata Breb. 
„ rotata Rifs. 
„ eotata var. acutidentata var. n. (Fig. 10.) 
Terminal lobes of semi-cells bilobulate, with bidentate lobuli. 
Some of the lobuli of the lateral lobes tridentate, especially those at 
each extremity. Teeth of terminal lobes much sharper than in the 
normal form. In the Punchbowl. 
Micrasterias truncata Breb. 
,, „ var. tridentata mihi. 
„ crenata Breb. 
f Erroneously given in Cooke as ill. Greyi. 
