ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 737 



previously stated view is correct, viz., that the oospheres produce now 

 Gutleria, now Aglaozonia. They prove it for the parthenogenetic 

 oospheres only, but a priori the same applies to the fecundated 

 oospheres. 



The ordinary methods of studying the germination of the repro- 

 ductive bodies of algas are unsatisfactory, affording much doubt as to 

 the purity of the culture. Sauvageau's method* is as follows. He 

 employs only small fragments of the plant, carefully selected, cleaned 

 and washed, and placed in a drop of filtered water in a moist chamber 

 (a Yan Tieghem cell). He used a cover-glass for conjugating spores, 

 etc., and an ordinary slide for advanced stages of germination. But 

 as the latter are too smooth, and allow the young plants to peel off 

 after a time, he has found it better to take the polish off the surface 

 previously by exposing the particular area on the slide to the fumes of 

 hydrofluoric acid. The finely roughened surface obtained permits the 

 plants to attach themselves very firmly, and does not interfere much 

 with microscopic observation. 



He describes f the development of Halopteris (Stgpocaulon) scoparia. 

 The germination of the zoospores is indirect, as in Cladostephus, but in 

 a different manner. The rather intricate stages of development, 

 described in detail, are not due to malformations, but were followed 

 out in hundreds of plants. Halopteris is heterogamous ; and possibly 

 the development of the oospore, if it contains sufficient reserve 

 material, will turn out to be direct. 



He adds J some further observations to his recent account of Fuciis 

 lutarius, which living partly in mud, multiplies itself by producing there 

 an abundance of adventive shoots. The plant can also live an almost 

 aerial and epiphytic life. On salt marshes at Arcachon it lies concealed 

 among stems of Spartina ; it hangs on the branches of Salicomia and 

 other plants, protected from desiccation at low tide by a covering of 

 E titer omorpha. Further, it is no longer to be regarded as a sterile 

 species ; for Sauvageau has lately found numerous specimens bearing 

 receptacles, especially among those with sub-aerial growth. All the 

 fifty receptacles examined were exclusively female ; no sign of dehis- 

 cence was found in any of them. The plant is apogamous (sensu 

 De Bary) ; possibly it may rarely be parthenogenetic. 



He publishes § some further observations on the parthenogenetic 

 germination of Gutleria adspersa. A fresh set of cultures showed after 

 some months a nearly equal proportion of Aglaozonia and Gutleria 

 plantlets. The germination of the zoospores, as well as of the 

 oospheres, of this plant gives in the same culture asexual or sexual 

 plants, the latter indifferently male or female. And in nature, although 

 conditions may seem to facilitate the development of this or that form 

 (the sexual state is very rare or absent in the northern seas), yet they 

 do not provoke it. The effect of warm weather upon the cultures was 

 to encourage the Aglaozonia (asexual state), and nearly destroy the 

 Gutleria (sexual state). The antheridia were dead ; but the indehisced 



* C.R. Soc. Biol. Paris, lxiv. (1908) pp. 700-1. 



t Op. cit., lxv. (1908) pp. 162-3. 



I Tom. cit., pp. 163-5. § Tom. cit., pp. 165-7.' 



