/"rcenian : OBSERVATIONS ox CONSTANTINEA. 189 



area showing the dichotomy of the branching. Camera lucida for an 

 outline, x 250. 



Fig. 19. Cross section of stipe including the cortical and the begin- 

 ning of intermediate layer. The cut off ends of elongated central fila- 

 ments are seen in the intermediate area. Camera lucida. x 130. 



Fig. 20. Cross section of stipe in the central area ; shows the pre- 

 dominance of elongated filaments, x 250. Outlined with camera 

 lucida. 



Fig. 21. Longitudinal section of a stipe at the inner edge of the 

 cortex ; shows the complication of the elongated filaments. Outlined 

 with camera lucida. x 250. 



Fig. 22. External view of holdfast seen from below, x */ . 



Fig. 23. Diagram of cross section of a holdfast, m. layer of disor- 

 ganized mass on lower surface by which the holdfast adheres. 



Fig. 24. Lower portion of the cross section of the holdfast showing 

 the attaching layer m. Camera lucida. x 250. 



Fig. 25. Diagram of a cross section of a frond showing the distri- 

 bution of an endophytic alga (probably Chlorochytriuni) . Larger 

 number on the upper surface, end. endophyte. 



Figs. 26 and 27. Cross section of a frond ; detail drawing of endo- 

 phyte. iv. endophyte wall. pd. pyrenoid. n. cell of nurse plant in 

 'outline. Camera lucida. x 250. 



BIBLIOGRAPHY. 



1. Gmelin, S. G. Historia Fucorum. 1768. 



2. Postels, A., and Ruprecht, F. Illustrationes Algarum in itinere 

 circa orbem jussu Imperatoris Nicolai. I. i8,^/. ^p, f. 88. 1840. 



3. Zanardini, G. Saggio di classificazione naturale delle Ficee con 

 nuovi Studi sopra 1'Androsace degli Antichi. 49. 1843. 



4. Kiitzing, F. T. Phycologia Generalis. 400. 1843. 



5. Kiitzing, F. T. Species Algarum. 744. 1849. 



6. Agardh,J. Species, Genera etOrdines Algarum. 2:295. 1851. 



7. Harvey, W. H. Nereis Boreali- Americana i: 21 ; 2: 160, 173. 



'853- 



8. Harvey, W. H. Notice of a Collection of Algae made on the 

 Northwest Coast of North America, chiefly at Vancouver's Island, by 

 David Lyall, Esq., M.D., R.N., in the years 1859-61. Journ. 

 Linn. Soc. Bot. 6: 172. 1862. 



9. Kiitzing, F. T. Tabula- Phycologicas 17: 24. pi. 83. 1867. 



10. Zanardini, G. Iconographia Phycologica Adriatica 2 : pi. 78. 

 1860-76. 



11. Agardh, J. Species, Genera et Ordines Algarum. 3: 225. 

 1876. 



