ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 679 



thallus is dorsiventral, with sympodial branching, and the plant 

 resembles in appearance a minute cauliflower. Cystocarps and tetra- 

 spores are described. The carpospores are pyriform, like those of 

 Dasyopsis, but it differs from that genus in having pericentral cells. 

 The other species referred to in this paper is GelkUum rigidum Vahl., 

 which should be placed in Gelidiopsis. It agrees with Gelidiopsis in 

 having a fan-like disposition of the apical cells, while Gelidium has one 

 large apical cell. The hyphae which characterise Gelidium are wanting 

 in G. rigidum, and the structure of the tetrasporous branches is identical 

 with those of Gelidiopsis var labile. 



Florideae of the Gulf of Spezia.* — This is the first part of a paper 

 by A. Preda, on the algal flora of the Gulf of Spezia. Seventy-three 

 species are given, and among them Bornetia secuiidiflora, which is 

 recorded as growing on a rhizome of Posidonia. 



Genicula of Corallinese.t — K. Yendo publishes the results of his 

 study on the genicula of the Corallineae, a subject which has lately 

 received attention from another botanist. After a short introduction, 

 he opens his paper with a description of the external appearance of the 

 genicula, and gives diagrammatic figures which make his meaning clear. 

 He considers that the genicula may be classified according to five 

 different types, distinguishable by the naked eye. These differences 

 are due to a diversity in the method of development in the early stages 

 of the plant. He discusses the position of genicula, both normal and 

 abnormal ; the relative position of the genicular and articular cells ; the 

 structure of the genicular cells, and comparison with articular cells ; 

 the formation and development of the geniculum ; the difference in the 

 properties of the cell-wall of articular and genicular cells ; and lastly, 

 the value of the geniculum as a systematic character. The subject is 

 worked out in great detail, and the genicula of several genera are 

 figured. 



British Fresh-water Algae.}— G. S. "West embodies in a Treatise on 

 the British Fresh-water Alga?, the results of his studies on this group. 

 Many new facts and suggestions concerning their life-histories, develop- 

 ment and relationships are here brought forward. A short preface 

 explains the lines on which the book is written and the necessity for 

 such a book. The contents are divided into two sections. The first is 

 an Introduction, which gives a short historical sketch of the principal 

 works hitherto published on the -subject ; and information on the 

 Occurrence, Collection, Preservation and Cultivation of Fresh-water 

 Algae. In the second section the author shortly diagnoses the six classes 

 of Algae in general, and then turns to Fresh- water Algas in particular ; 

 describing their Vegetative multiplication, Asexual reproduction, Sexual 

 reproduction, Polymorphism, and Phylogeny and Classification. To the 

 latter subject thirteen pages are devoted, and diagrams represent the 

 views of the author on this subject. The algae are then dealt with 

 under their various orders. Each genus is fully described, with short 



* Malpighia, xviii. (1904) pp. 76-93. 



t Journ. Coll. Sci. Tokyo, 1904, Art. 14, 44 pp., 1 pi. 



X Cambridge Biol. Ser. (1904) 8vo, xv. and 373 pp., 166 figs, in text. 



3 A 2 



