ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
565 
His experiments were carried out on species belonging to three different 
families, — Protococcaceae, Ulothrichacuse ( Ulothrix , Hormidium , Sticho- 
coccus), and Chaetophoraceee ( Microti tamnion ). 
Herr 0. Loew * contests the accuracy of one or two statements made 
by Benecke, and the latter replies, f 
Germination of the Cutleriacese.J — M. C. Sauvageau compares the 
structure of the thallus of Gutleria or Zanardinia to that of filaments of 
Ectocarpus united laterally. Two modes of germination have been ob- 
served in the family : — the parthenogenetic development of the oospheres 
of Cutler ia multijida, observed by Thuret ; and the germination of im- 
pregnated oospheres described by Falkenberg. The former give rise to 
plants resembling a young Ectocarpus, the latter to the form known as 
Aglaozonia. M. Sauvageau confirms the occurrence of both these modes 
of germination in the case of Gutleria adspersa, and states that the two 
modes are not due to differences of habitat, season, or temperature, but 
that they occur side by side on the same substratum. There are no 
intermediate conditions between these two modes of germination. 
Bangia pumila. §— Mr. 0. Y. Harbishire describes this endemic 
species of the eastern Baltic. Besides the vegetative mode of propaga- 
tion, he was able to follow out in this species a sexual mode. The 
antherids consist of cells in which the contents have divided into a large 
number of “spermatia” by repeated quadripartition. The “ sperma- 
tium ” enters the procarp through a small orifice. Cystocarps are formed 
on branches on which the procarps have been impregnated. 
Laminariacese.U — Prof. N. Wille has studied in detail the anatomical 
structure of Alaria esculenta, which he regards as the highest northern 
type of the Laminariaceee, especially in the following points : — the inter- 
calary zone of growth in the stipe ; the structure of the stipe ; the 
formation and structure of the rhizoids ; the structure of the mid-rib, 
of the sterile surface of the leaf, and of the sporophyll. The assimilating 
tissue is confined to a single outermost layer of cells. The conducting 
elements are partly sieve-cells formed from the meristematic cells, partly 
sieve-hyphae. The former may lose their function with age, and become 
closed bv plugs of cellulose. The rhizoids are formed from the super- 
ficial layer in the lower part of the stipe The sporophyll may persist 
for a whole year, and the stipe may live for several years. In the 
formation of the sporanges there is a great increase in the number of 
chromatophores. The trichomic structures contribute to the nourishment 
of the plant. The intercellular substance consists, in the opinion of the 
author, essentially of calcium pectinate ; while the inner lamella of the 
cell-wall shows the reactions of cellulose. 
Centrosome of Dictyota.^T —After a summary of what is at present 
known as to the existence of centrosomes in the vegetable kingdom, 
Mr. D. M. Mottier describes his discovery of them in Dictyota dichotoma, 
* Op. cit., 2 te Abt., pp. 235-6. f Tom. cit., p. 236. 
% Comptes Rendus, exxvi. (1898) pp. 1435-8. Of. this Journal, ante, p. 453. 
§ Komm. wiss. Unters. d. Deutsch. Meere in Kiel, iii. (1898). See Hedwi^ia, 
xxxvii. (1898) Rep., p. 106. 
|| Beitr. z. Phys. Anat. d. Laminariacecu, Christiania, 1897, 70 pp. and 1 pi. See 
Bot. Centraibl., lxxxiii. (189S) p. 388. 
H Ber. Deutsch. Bot, Gesell., xvi. (1898) pp. 123-8 (5 figs.). 
2 q 2 
