310 DR. LILY BATTEN ON 
Fig. 
. TRAILL, G. W.—Alphabetical List of Parasitical Algæ of Firth of Forth. 
. WRIGHT, E. P.—On the Form of so-called Siphons and Development of Tetraspores in 
Polysiphonia. Trans. Roy. Irish Acad. p. 47 et seq. 
. WYATT, Mary.—Algw Damnonienses. Torquay, 1833. 
. Yamanoucut, S.—Tetraspores on Sexual Plants in Polysiphonia. Bot. Gaz. vol. xli 
1906, p. 435. 
. ——— Polysiphonia violacea. Prelim, Note. Ibid. vol. xli. p. 425. 
. ——— Life-history of Polysiphonia violacea, Ibid. vol. xlii. pp. 401-449. 
. ZANARDINI, G.—Synopsis Algarum in Mari Adriatico. Taurini, 1842. 
EXPLANATION OF THE PLATES. 
PLATE 22. 
. Protoplasmic connections of the central siphon in P. elongata. 
2, Attachment disc of P. fruticulosa, seen from below. 
3. Tip of lateral branch of P. urceolata, 
4. Central siphon of P. fastigiata, showing protoplasmic connections and thickened 
walls, 
5. Development of rhizoids from the pericentral siphons of P. macrocarpa. 
6. Formation of rhizoids from the corticating cells in P, nigrescens. 
7. Transverse section of thallus of Ascophyllum nodosum, showing penetration by the 
rhizoids of P. fastigiata (constructed from a number of sections). 
. T. S. of thallus of Ascophyllum nodosum at the point of penetration of P. fastigiata, 
showing decolorised cells which have been attacked. Cam, luc. 
9. T. S. of thallus of P. fastigiata in region bearing tetraspores, 
10. P. insidiosa. T. S. of thallus, 
co 
11. » Habit drawing. 
12. P. macrocarpa. Portion of thallus showing attachment organs. 
13. » Habit drawing. 
14. " T. S. of thallus, 
15. P.rhunensis. Habit drawing. 
16. P. spiralis, spec. nov. Plan showing relative positions of twisted and untwisted 
portions, 
17. ” Branch bearing tetraspores. 
18. » T. S. of thallus. 
19. " Portion of thallus showing spiral twisting of the siphons. 
20. » Habit drawing. 
9]. » Portion of thallus showing attachment organ. 
22. » Dranch bearing tetraspores. 
23. P. urceolata. Habit drawing. 
PLATE 23, 
24. P. urceolata. Portion of thallus bearing attachment organs. 
25. , T. S. of thallus. . 
26. P. atro-rubescens. Portion of thallus showing spiral twisting of the siphons. 
27. » Portion of thallus showing attachment organs. 
28. » T. S. of thallus. 
99. Habit drawing. 
» 
30. P. fastigiata. T. S. of thallus. 
3l. " Habit drawing showing various stages in the developiuent of the 
Polysiphonia on Ascophy” m nodosum. 
82. P. furcellata. Habit drawing. 
