ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 219 



Fucus platycarpus and F. lutarius.*— C. Sauvageau writes with 

 much detail about two species of Funis collected at Arcachon — F. platy- 

 carpus and F. lutarius. 1. He shows that the name F. spiralis Linn, 

 has no precise meaning, and cannot be used to replace F. platycarpus 

 Thuret, a southern species, with which must be united the F. spiralis, 

 F. Areschougii, F. Sherardi, F. versoides of authors. F. versoides has 

 been accidentally introduced into the Adriatic and become naturalised. 

 Sauvageau proposes three varieties of F. platycarpus, namely, typka, 

 spiralis, and Umitaneus. 2. As to F. lutarius Kuetz., he holds it to be 

 worthy of specific rank. It grows on mud, or on bunches of littoral 

 phanerogamic plants where protected from desiccation by Chlorophycese. 

 The spiral frond possesses numerous piliferous crypts. The type possesses 

 no acrocysts, however, in the north of Spain, and in England vesicu- 

 liferous specimens are found. He separates off from it the new variety 

 inrassonensis. He suggests that histological researches may serve to 

 settle the real affinities of the limicolous forms of Fucus. 



Cytology of Porphyra.f — S. M. Wislouch treats of the anatomy of 

 the cell in Porphyra, and confirms the observations of previous investi- 

 gators as to the structure of the cuticle aud cell-membranes. The cell- 

 wall appears to be composed of hemi-cellulose, inasmuch as it responds 

 negatively to cellulose reactions. He gives some new figures of the 

 chromatophores, and describes a radiating type of structure not previously 

 observed in them. The large roundish body situated in the centre of the 

 cell, hitherto supposed to be the nucleus, is the pyrenoid of the chroma- 

 tophore. The real cell-nucleus is very much smaller, 1 ■ 5-2 /*, and lies 

 sideways between the cross-divisions of the chromatophore. The author 

 corrects the views of Haberlandt as to the position of the nucleus in the 

 basal cells — those which bear rhizoidal protuberances. The nucleus is 

 situated in the older part of the cell, and not in the actively growing 

 part. 



Ceramium radiculosum, a Brackish-water Species.! — J. Schiller 

 treats of the morphology and biology of Ceramium radiculosum Grim., 

 one of the few red algte which have established themselves in brackish- 

 water. It occurs above the mouth of the river Timavo near Monfalcone, 

 on the Adriatic. He describes and figures its structure, and carefully 

 considers its distribution and the physical factors of its environment. 

 He shows that it ascends the river as far as the brackish-water goes at 

 flood tide, and that it descends towards the river mouth at least as far 

 as the fresh-water penetrates during the ebb ; and that during the 

 twenty-four hours the plants are thus twice washed over by fresh-water 

 and twice by brackish-water. He shows that the values of the salinity 

 of the water of the two periods lies between 0*05 and 2*85 p.c. ; and 

 that the alga requires that the water shall be quick flowing, clean and 

 not above 20° C. He describes also the formation of the rhizoids by 

 which the Ceramium splits open the tissue of the plant which serves as 

 matrix — Zostera, Scirpus, Potamogeton, or Enteromorpha. 



* Bull. Stat. Biol. Arcachon, 1908, 160 pp. 



t Bull. Jard. lmper. Bot. St. P^tersbourg, viii. (1908) pp. 89-101 (figs.). 



J Oesterr. Bot. Zeitschr., lviii. (1908) pp. 49-54, 111-18 (1 pi. and figs.). 



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