ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 329 



ment laid down by the author, as also do the manner of cell-division 

 and the periodicity in the complete development of a species. Com- 

 parisons are drawn between the various types, and a sketch of the new 

 system founded on these characters is given. The method of examina- 

 tion consisted in emptying the cell of a fresh Desmid of its contents 

 by means of pressure, then of staining the different elements of the 

 membrane with water-solutions of fuchsin, methyl-violet, and Bismarck- 

 brown, and finally clearing the preparation with acetic acid. 



Dichotomosiphon tuberosus.* — Under this name A. Ernst describes 

 a new fresh-water alga allied to Vaucheria, which possesses, like that 

 genus, oogonia and antheridia. It also shows a form of non-sexual 

 reproduction hitherto unknown among Siphoneae. Towards the end of 

 the vegetative period elongated swollen bodies are formed at the ends 

 of the rhizoids. These bodies are filled with a dense protoplasm and 

 contain chlorophyll and starch. They become divided off from the 

 plant by a transverse wall, and in about two months new filaments arise 

 from any part of their surface. The author refers to Vaucheria tuberosa 

 Kutzing as being identical with his plant, but he maintains that it is 

 more nearly allied to Codium, Halimeda, and Udotea than to Vaucheria, 

 on account of the dichotomous branching and the internal thickening 

 of the membrane in places. 



Bryopsis plumosa.f — E. Perceval Wright has cultivated this species 

 and found that in certain cases the lowermost pinnae gave rise to 

 rhizoids and then dropped off, growing as independent plants. Some 

 dropped off having no rhizoids, and formed long, irregular, siphonaceous 

 growths resembling Vaucheria. Sometimes the protoplasm took the 

 appearance of oogonia, but no sort of reproduction Avas seen. The 

 plants then died from attacks of minute parasitic algae. 



Mastogloia fimbriata and M. binotata.f — E. Perceval Wright 

 publishes notes by Dr. Dixon on the periglcea and the tentaculoids of 

 these two species. A comparison between them shows certain differences 

 in the minute structure. A short account is given of previous work on 

 the subject, as well as the geographical distribution of four species of 

 Mastogloia (Orthoneis). 



Macrocystis pyrifera.§ — C. Skottsberg gives some notes on this 

 alga concerning its manner of growth, habitat, length, and the depth at 

 which it grows. He criticises statements made by J. D. Hooker in the 

 Flora Antarctica as to the length of a single plant, considering that the 

 alga is not so long, nor does it grow from such great depth as is there 

 described. 



Eisenia and Ecklonia.|| — K. Yendo has made a study of Eisenia 

 arborea Aresch. and of Ecklonia bicyclis Kjellm. He considers that 

 E. bicyclis is merely a form of Eisenia arborea, and names it E. arborea 

 forma bicyclis Yendo. 



* Arch. Sci. Phys. Nat. Geneva, xiv. (1902) pp. 506-10. 



f Notes Bot. School Trin. Coll Dublin, 1902, pp. 174-5 (pi. ix. figs. E, F). 



t Tom. nit., pp. 161-5 (pi. ix. figs. A-D). 



§ Bot. Notis.. 1903, pp. 40-4. 



II Bot. Mag. Tokyo, xvi. (1902) pp. 203-6 (figs. A, B). 



