8 Transactions of the Society. 



II. — Fresh-ivater Algx {including CliloroplujUaceous Protopliyta) 

 of North Cormvall ; with descrijyiions of six new species. 



By Alfked W. Bennett, F.E.M.S., F.L.S., Lecturer on Botany 

 at St. Thomas's Hospital. 



(Bead 12th January, .1887.) 

 Plates III. and IV. 



So little is known accurately of the geographical distribution of any of 

 our fresh-water algae, that it seems to me a complete record may not be 

 without value of all the species observed during a six weeks' stay in 

 North Cornwall, in August and the early part of September 1886. The 

 localities from which gatherings were made were entirely in the northern 

 part of the county, from Boscastle to Newquay, a distance of about 

 thirty miles, and mostly within a short distance of the sea. This is 

 chiefly a limestone country, no granitic or other volcanic districts having 

 been visited. It is characterized by the entire absence of peat-bogs 

 over a large portion of the area ; but the few examined, at Mawgan, 

 Koche, and St. Denis, were rich in desmids and other organisms. 



On comparing this list with that made in the ]3revious year in the 

 English Lake Country, they are seen to differ considerably.* It is not, 

 however, in any way suggested that either list approaches completeness, 

 or that the species wiiich occur in one only of the lists may not ulti- 

 mately be found in both districts. In order to facilitate the comparison 

 I have prefixed an * in the present list to those species not included 

 in that for the Lake District. Some general comparisons between the 

 two may, however, be interesting. 



EXPLANATION OF PLATES III. and IV. 



Fig. \. — Apiocystis Bvauniana Nag. x 200. 



„ 2. — Hydiianum hetcromorplium Eeinsch X 400. 



,, 3. — Apbanothece microscopica Nag. x 100. 



„ 4. — 0.scillaria princeiis Vaucb. x 200. 



,, 5. — Stigoncma uiinutum Hass. ? (outline only) x 100. 



„ C, 7. ,. „ portions of primary filament X 200. 



„ 8. „ „ portion of prim:iry filament, showing attachment of 



branch, x 200. 



„ 9, 10 „ „ portions of branch, X 200. 



„ 11. — Pediastrum integrum Nag., young ccenobium x 300. 



., 12. „ „ older ccenobium x 300. 



„ 13. „ „ portion of ditto, showing possible resting-cell 



a, X 400. 



,, 14. — Coclastrum cubicum Nag. x 600. 



., 15. — Selenastrum bifidum Bonn, x 400. 



„ 16. „ „ „ single cell x 600. 



„ 17. — Docidium granulatum Benn. x 400. 



„ 18.— Euastrum oblongnm rilrev. var. integrum Benn. x 200. 



„ 19. — „ cra^-.'sum Breb. var. cornubiense Benn. x 200. 



„ 20. — „ crenulatum Bonn., froiit view x 600. 



„ 21. „ „ „ end view x 600. 



„ 22. — Cosmarium spliericum Benn. x 300. 



„ 23. „ discretum Benn. x 400. 



„ 24. — Staurastrum cornubiense Benn. x 800. 



* This Journal, 1886, pp. 1-15. 



