Freshwater Algae of S. of England. By W. & G. S. West. 469 
recent work at this group of plants. For the filamentous Myxo- 
phycese (Cyanophyceae), i.e. the Nostochaceae Heterocystae and Nos- 
tochaceae Homocystae, we follow the classification and also the nomen- 
clature of Bornet and Flahault’s 4 Revision des Nostocacees Hetero- 
cyst ees ’ and Gomont’s ‘ Monographie des Oscillariees.’ 
The following is a more detailed account of the collections. To 
save space, contractions are used (throughout the paper) for the 
localities. 
I. Essex . — The only part investigated was Epping Forest, in 
which gatherings were made from ditches, hogs, squeezings of 
Sphagnum and Hypnum from several ponds, and washings of Myrio- 
phyllum and Potamogeton from a deep fish-pond. 
Ep. = Epping Forest. 
II. Middlesex . — Mostly collections from ponds and ditches in 
various parts of the county. 
Bg. = Bow Green. 
Ha. = Harefield. 
Hy. = Hyde Park. 
Ki. = Kingsbury. 
Kg. = Kingsbury Green. 
No. = Northwood. 
Pi. = Pinner. 
Ru. = Ruislip Reservoir. 
U. = Uxbridge Common. 
Wh. = Welsh Harp. 
III. Surrey . — By far the most numerous and varied gatherings 
were made in this county, during several years and at all seasons of 
the year. In the northern portion of the county, Esher West-end 
Common, Chobham Common, and Bisley Common, were much more 
productive than any of the other surrounding commons. In the 
south-east corner of the county a few very interesting species were 
obtained from some large ponds north of Felbridge, one locality 
quoted as “ Mill-pond E. of Chapel Wood ” being very rich. In the 
south-west corner, the Frensham district was fairly productive, but 
Thursley and Puttenham Commons were much the best. On the 
Plate VII. 
Fig. 1, 2. — Scenedesmus gramdatus sp. n. x 520. 
„ 3. — Cosmarium truncatellum Perty. X 520. 
„ 4, 5. — Tetraedron horridum sp. n. X 520. 
„ 6, 7. — (Edogonium macrospermum sp. n. x 520. 
„ 8. — BhapMdium polymorplium Fresen. var. tumidum var. n. x 520. 
„ 9-13. „ „ var. mirabile var. n. x 520. a, moving 
corpuscle. 
„ 14. — Staurastrum margaritaceum (Elirenb.) Menegh. var. robustum var. n. x 520. 
„ 15-17. „ „ var. subcontortum var. n. 
X 520. 
„ 18. — Dactylococcus bicaudatus A. Br. var. exilis var. n. x 520. 
„ 19. „ dispar sp. n. x 520. 
„ 20. — Arthrodesmus Incus (Breb.) Hass. var. subquadratus var. n. X 520. 
„ 21-23. — Tetraedron minimum (A. Br.) Hansg. x 520. 
„ 24. — Cosmarium adoxum sp. n. X 740. 
„ 25-28. — Ammatoidea Normanii gen. et sp. n. x 520. 
