ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 557 



Glasgow, giving interesting particulars respecting the original discovery 

 of Fragilaria Harrisonii near the remains of the ancient Priory of 

 Haltemprice in Yorkshire. These particulars he gives here. The 

 species has been lately removed from Fragilaria to the genus Staurosira 

 by Peragallo. A figure of the diatom is given attached to a sand grain. 



Diatoms from Nyassaland.* — 0. Midler publishes the second part 

 of his report on the Bacillariaceae collected by the German expedition 

 to Lake Nyassa and the Kinga mountains. A certain number of new 

 species and varieties are described, belonging to the section Discoidege- 

 CoscinodisceaB ; with an addendum to Surirellese, carried on from the 

 last paper. Several of the species are treated in morphological groups, 

 and each record is followed by critical notes. Eemarks are made on the 

 subgenus Orthosira, and on mutation by jumps. 



£<] Studies in the Dictyotacese.f — J. Lloyd "Williams publishes under 

 the above title two interesting communications : (1) the Cytology of the 

 Tetrasporangium and the Germinating Tetraspore ; and (2) the Cytology 

 of the Gametophyte Generation. The author divides his first paper 

 into the following sections : the stalk-cell division ; the first, or reduc- 

 ing division of the tetraspore mother-cell ; the second, mitosis in the 

 tetraspore mother-cell ; karyokinesis in the germinating tetraspore ; 

 abnormalities ; conclusions. The latter section is divided into (1) the 

 alternation of generations, and (2) the nucleolus. The author has worked 

 out the cytology of all the various kinds of cells in the three forms of 

 Dictyota, male, female and asexual, and he considers that so far as cyto- 

 logical evidence is concerned, there seems to be no reason to doubt that 

 there is here a clear case of alternation of generations. In the second 

 paper the author describes the development of the oosphere and anthero- 

 zoid, the fertilization of the ovum and its subsequent segmentation, to- 

 gether with the parthenogenesis of unfertilized eggs — the observations 

 in this case applying to Dictyota dichotoma only. The sections of this 

 paper are entitled : the development of the oogonia ; the development 

 of the antheridium ; the fertilization of the egg ; the segmentation of 

 the fertilized egg ; the parthenogenesis of unfertilized eggs ; general 

 considerations ; summary. It is found that the sexual cells, unlike 

 the tetraspores, are produced and liberated simultaneously in fortnightly 

 crops. Fertilization takes place externally. Eggs not fertilized within 

 about half or three-quarters of an hour after liberation become invested 

 with walls and germinate parthenogenetically. The oogonium and anthe- 

 ridium are produced by the increased growth of surface cells, which, after 

 cutting off a stalk-cell, form respectively a single egg, or over 1500 an- 

 therozoids. There is no division of the nucleus in the oogonium as 

 there is in that of Fucus. The nuclear division is described and figured 

 in detail. 



Corallinacese.J — A. Weber van Bosse and M. Foslie publish a mono- 

 graph on the Corallinaceai of the Siboga expedition to the Dutch East 

 Indies. M. Foslie is the author of the first part of the joint paper, and 



* Engler's Bot. Jahib., 1904, pp. 256-301 (2 pis., 4 figs, in text). 



t Ann. of Bot., xviii. (1904) pp. 141-GO (2 pis.) ; pp. 183-204 (3 pis.). 



% Siboga-Expeditic. Monogr.,;lxi. (Leiden, 1904) 110 pp. (1G pis., 34 figs, in text). 



