468 
Transactions of the Society. 
The results here set forth have been obtained by the gradual ex- 
amination for many years of a large and extensive series of algte- 
gatherings ranging over many of the counties of the south and south- 
west of England. A more detailed account of the collections (which 
were for the most part made by the authors) will be found below. 
All the species recorded for Frensham, the New Forest, and Dart- 
moor, are additional to those found at these respective localities by 
Mr. Bennett. 
In these gatherings no less than 52 species of Desmids have been 
observed with zygospores, many of them for the first time in that state. 
As might be expected, the more alpine and “ wet-rock ” species 
(such as Cosmarium anceps , G. Holmiense , C. nasutum, Staurastrum 
Meriani, S. Kjellmani, &c.) are, as far as we have observed, absent from 
all the eastern counties of the South of England. 
As it is impossible to accurately identify, from sterile specimens, 
the majority of plants belonging to the families (Edogoniaceae and 
Zygnemace.ae, no species of these orders are recorded in this paper 
unless they were seen in abundant fruit, with the exception of (Edo- 
gonium undulatum , which even in its barren state is unmistakable. 
The classification set forth in this paper is the one which we 
think to be the most natural, after taking into consideration all the 
Plate VI. 
(Explicatio iconum.) 
a, a ' = front view (a basi visa). 
b = vertical view (a vertice visa). 
c — side view (a latere visa). 
d = basal view of semi-cell (a basi visa). 
Fig. 1, 2 . — Closterium Siliquci sp. n. X 520. 
„ 3. „ lanceolatum Kiitz. var. parvum var. n. x 520. 
„ 4. „ Pritchardianum Arch. Apex of semi-cell, x 520. 
„ 5. „ „ Zygospore formed by the conjugation of three 
cells, x 120. 
,, 6 . — Sphasrozosma WaUichii Jacobs var. anglicum var. n. a et d, X 520 ; a', X 830. 
„ 7. „ vertebrcitum (Breb.) Ralfs var. latius var. n. x 520. 
„ 8, 9. — Penium subtile sp. n. 8, X 520 ; 9, x 660. 
,, 10 . — Cosmarium Blyttii Wille var. Novas Sylvas var. n. x 520. 
„ 11. „ fastidiosum sp. n. X 520. 
., 12. „ ocellatum B. Eichl. and Gutw. var. incrassatum var n. x_520. 
„ 13, 14. ,, sphagnicolum sp. n. x 520. 
,, 15. — Xanthidium concinnum Arch, x 740. 
,, 16. — Arthrodesmus octocornis Ehrenb. Zygospore x 520. 
„ 17 . — Cosmarium bioculatum Breb. Zygospore x 520. 
,, 18 . — Staurastrum rostellum Roy and Biss. var. erostellum var. n. x 660. 
„ 19 . — Cosmarium subpunctulatum Nordst. x 520. 
„ 20. „ subbroomei Schmidle, forma. X 520. 
„ 21. „ Ungerianum (Nag.) De Bary var. subtriplicatum var. n. X 520. 
„ 22 . — Staurastrum trachytithophorum sp. n. x 520. 
„ 23. „ nodosum sp. n. x 660. 
,, 24. — Cosmarium bioculatum Breb. var. Mans var. n. x 520. 
„ 25. — Staurastrum tetracerum Ralfs var. validum var. n. x 520. 
„ 26. — Cosmarium Cucurbita Breb. Zygospore x 520. 
„ 27 . — Staurastrum gracile Ralfs. Zygospore X 520. 
