ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 479 



summarises his results as follows : — 1. The current figures and descrip- 

 tions of the chromatophore of Closterium derived from Naegeli are 

 fundamentally incorrect. The chromatophore is not made up of a 

 series of radiating plates about a slender central core, but is a curved 

 cone-shaped structure with relatively narrow ridges on its surface. 2. The 

 pyrenoids are imbedded in the periphery of this chromatophore in 

 G. Ehrenbergii and exactly at its centre in G. moniliferum. 3. Pyrenoid 

 starch and stroma starch both have the same origin, all the starch being 

 formed around pyrenoids. 4. The pyrenoids show considerable internal 

 structure, frequently containing denser and lighter portions, vacuoles, 

 etc., and often are cleft into a mass of disks or segments of varying 

 number and form. 



Trentepohlia.* — F. Brand discusses the various sporangia of the 

 genus Trentepohlia, of which he finds three different kinds, the differ- 

 ence lying not in the form of the sporangium itself, but in the form of 

 the cell which bears it. Thus there is : — 1. The sessile sporangium, 

 which may be terminal, lateral, or intercalary, possesses no marked 

 annular thickenings on its dividing wall, is never separated from the 

 filament, and empties its spores in situ. 2. The pedicellate sporangium, 

 which does not arise direct from a vegetative cell, but is divided off from 

 the apex of a filamentous outgrowth of the somewhat swollen sporangio- 

 phore. This type occurs only apically or laterally on the filaments, has 

 mostly concentrical rings of thickening in the septum, and before the 

 escape of the spores breaks away from its stalk. 3. A short membranous 

 funnel is formed on the cylindrical sporangiophore by subapical con- 

 strictions. Inside the funnel the young sporangium is divided off by a 

 wall, which has two annular thickenings one over the other. This is 

 called the funnel-sporangium, and is always apical. It always falls off 

 from the sporangiophore before the escape of the spores. Details of 

 these three forms of sporangia are given, and instances are quoted. 

 Further, the author adds some notes on T. annulata Brand, which he 

 has found in a new locality, and on the culture of Trentepohlia. 



Cystosira and Sargassum. f — W. Nienburg has re-investigated the 

 development of the conceptacles and oogonia of Sargassum and Cystosira, 

 previously worked out by E. B. Simons, and finds that her conclusions 

 as to the formation of the conceptacle are, as was to be expected, quite 

 correct. She found that the early stages of the conceptacle in Sargassum 

 Filipendula differ somewhat from those of other Fucaceous genera, de- 

 scribed by Bower and Oltmanns. The same holds good for Gystosira 

 barbata. As regards the development of the oogonia, the author of this 

 paper does not quite agree with E. B. Simons, and sets forth the points 

 on which he differs. He finds that the oogonia of both Gystosira and 

 Sargassum show the usual nuclear division into three, and that in the 

 former there follows a reduction of the chromosomes. Therefore these 

 two genera are not exceptions to the rule, which apparently holds good 

 for all Fucaceas, that in the cycle of their development an ^-generation 

 enclosed in the oogonium alternates with a 2z-generation. 



* Ber. Deutsch. Bot. Gesell. xxviii. (1910) pp. 83-91 (1 pi.). 

 . t Flora, n.s., i. (1910) pp. 167-80 (figs, in text). 



