THE FRESHWATER PLANKTON OF THE SCOTTISH LOCHS. 
3, 4. Desmidium occidentale, sp.n. x 400. 
5). £ coarctatum, Nordst., var. cambricum, West. x 400. 
6. Hyalotheca Indica, Turn. x 520. 
7. Spherozosma Aubertianum, West. x 520. 
8, 9. Botryococcus protuberans, sp. n. Small portions of two colonies. x 520. 
10, 11. Tetraédron limneticum, Borge, forma. x 520. 
12. Celastrum Morus, W. & G.S. West. x 520. 
13. Pediastrum Boryanum (Turp.), Menegh. Large ccenobium, x 520. z, empty zoogoni- 
dangia, showing slit through which the zoogonidia escaped. 
14. Pleodorina californica, Shaw.  v.c., vegetative cells ; g.c., gonidial cells. 
15, 16. Phexococcus planctonicus, sp.n, x 520. 
17-19. Actinobotrys confertus, gen. et sp.n. 17 and 18, two colonies, the mucous investment not 
being represented, x 520; 19, single cell to show parietal chloroplast, x 1000. 
20. Closterium aceroswm (Schrank), Ehrenb., forma minor, x 520. 
21. 5 setacewm, Ehrenb., var. elongatuwm, var.n. x 250. 
22. $9 Kiitzingti, Bréb., var. onychosporum, var.n. x 520, 
23. Rhizosolenia eriensis, H. L. Sm., var. morsa, var. n. Extremity of large specimen. 
PrATE if. 
1. Cosmarium Botrytis (Bory), Menegh., var. depressum, var.n. x 430. 
ee) 5 capitulum, Roy & Biss., var. grenlandicum, Borges. x 520. 
4, 5. es moniliforme (Turp.) Ralfs, forma panduriformis, Heimerl. x 520. 
6. 5 Another smaller form of f. panduriformis. x 520. 
Up Sianeasinae Tohopekaligense, Wolle, var. trifurcatum, W. & G. 8. West forma. 
sh, 9) 5 anatinum, Cooke & Wills, var. longibrachiatum, var.n. x 520, 
11, 12. Staurastrum inelegans, sp.n. x 520. 
sy, 5 paradoxum, Meyen, var. longipes, Nordst. x 520, 
14. Pe He es - forma permagna, x 520. 
15. = brevispinum, Bréb., var. obversum, var.n. x 520. 
16. x 5 var. altum, var.n. x 520. 
17. i forficulatum, Lund. x 520. 
18,119. bs subnudibrachiatum, sp.n. x 520. 
20. _ sibiricum, Borge. x 520. 
21. Xanthidium antilopeum (Bréb.), Kiitz., var. Hebridarum, var.n. x 520. 
22. Arthrodesmus Incus (Bréb.), Hass., var. longispinum, var.n. x 520. 
10. Arthrodesmus Incus (Bréb.), Hass., var. Ralfsii, W. & G.S. West forma. x 520. 
x 520. 
23. Staurastrum sublevispinum, W. & G.S. West. x 520. Individual showing the initial 
stage of division. 
24. 55 Sebaldi, Reinsch, var. productum, var.n. x 520. 
