Freshwater Algee of S. of England . By W. & G. S. West 501 
Yar. duplex (Kiitz.) Rabenh. III. Fh. 
Var. tumidum var. n. (PI. VII. fig. 8.) 
Yar. cellulis solitariis vel subsolitariis, curvatis, in medio 
inflatis, apicibus acutissimis. 
Long. 61-73 p; lat. 4 *5-6 *5 p. III. Pu., abundant. 
Yar. mirabile yar. n. (PI. VII. figs. 9-13.) 
Yar. cellulis semper solitariis, longissimis, variabiliter 
curvatis (nonnunquam sigmoideis), apicibus acutissi- 
mis. Long, usque 117 p ; lat. 2-3*5 p. 
III. Wi. ; in a pond amongst Conferva , July 1894 ; in 
same pond, Jan. 1895. 
The regularly curved forms of this variety are with difficulty 
distinguished from a minute Closterium. At or near the middle of the 
cells is a clear space, the chromatophores being completely interrupted, 
and towards the apices there is often present a clear space containing 
one minute moving corpuscle, but beyond this clear space there is 
sometimes a portion of the green cell-contents. The cell-contents are 
very irregular, and frequently much vacuolated. In a remark con- 
cerning the moving granules present towards the apices of the cells in 
the genus Closterium , Archer states (Quart. Journ. Micr. Sc., ii. 1862, 
pp. 257-8) that “ In Anhistrodesmus there are no such granules.” 
The latter genus is synonymous with Bhaphidium , and this plant was 
undoubtedly a Bhaphidium , and one which possessed these moving 
granules. 
2. B. convolution (Corda) Rabenh. III. Rp. 
Genus Selenastrum Reinsch. 
1. 8. Bibraeanum Reinsch. IY. Ks. 
*2. S. gracile Reinsch. III. Pu. 
Genus Lagerheimia (De Toni) Chodat. 
*1. L. genevensis Chodat. III. Mp. 
Genus Tetraedron Kiitz. 
1. T. minimum (A. Br.) Hansg. III. Fg., Mp., Th. 1Y. Ks. 
This was in large quantity from a pond on Keston Common, Kent. 
Many specimens showed the reproduction as described and figured by 
Lagerheim (Stud. Arktisc. Cryptog. I., Tetraedron u. Euastropsis, 
Tromso Mus. Aarsh. 17, 1894). Of. PI. VII. figs. 21-23. 
2. T. trigonum (Nag.) Hansg. I. Ep. III. Bi., Mp. 
3. T. tetragonum (Nag.) Hansg. III. Di. 
4. T. caudatum (Corda) Hansg. (Polyedrium pentaqonum 
Reinsch). III. Fg. 
Forma incisa Lagerh. II. U. III. Ra. IY. Ks. 
