ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 185 



Muscinese. 



Ephemeropsis Tjibodensis Goeb.* — M. Fleischer gives a full -de- 

 scription of this little-known moss, the protoneme of which forms round 

 greenish-yellow or reddish-brown spots on the leaves and steins of ferns 

 and flowering plants in Java. He regards it as the type of a distinct 

 family nearly related to the Hookeriaceae in the structure of the sporo- 

 gone and peristome. 



Braithwaite's British Moss-Flora. — Part XX. of this work is just 

 published, and continues the description of the Hypnaceas. The genus 

 Hypnum (including Brachytheciuin) is completed, numbering 43 British 

 species, and is followed by the small genera Lesquereuxia (4 sp.), Iso- 

 thecium (2 sp.), Pterogonium (1 sp.), and Pterygynandrum (1 sp.). The 

 six plates, Nos. 103—108, are of the usual excellence. 



Cell- and Nuclear-Division in Hepaticse.j — J. M. Van Hook finds 

 the process of the formation of the cell-plate to be essentially the same 

 in Anthoceros and Marchantia. In the cells of the stalks of the arche- 

 goniophore of Marchantia, the first noticeable evidence of nuclear divi- 

 sion is the pulling out of the nuclear membrane, generally in the 

 direction of the long axis of the cell, into two points which are opposite 

 to each other, and around which the chloroplasts tend to collect. At 

 each point from which conspicuous radiations extend is a minute body. 

 These are the centrospheres, which seem undoubtedly to exert a great 

 attractive force. The centrosomes appear as dark round bodies at the 

 centre of the centrospheres. They become invisible as soon as the 

 polar radiations have disappeared. As the nucleus increases in length, 

 the radiations become exceedingly distinct, and extend further over the 

 nuclear membrane, which they penetrate. Before they meet at the 

 middle from the two centrosomes to form the spindle, the linin threads 

 have become more conspicuous, with thickened or knotty portions ap- 

 pearing as chromatin. The number of chromosomes appears to vary 

 between five aud eight. When the spindle-fibres have extended to the 

 region of the equator, the nuclear membrane disappears, and the spindle 

 is formed. 



In the formation of the spore-mother-cells of Anthoceros no centro- 

 sphere could be detected. 



Algae. 



Agardh's Analecta Algologica.J — Tho last of the contributions of 

 the late Prof. J. G. Agardh to our knowledge of the Florideaa consists 

 of a number of detached articles, the most important of which is a 

 detailed review of the sub-genera and species of the genus Gigartina. 

 In the course of the remaining papers, the following new genera are 

 established. 



Dactylymenia, nearly related to the Kallymenieaa. Cystocarpia 

 nucleolis pluribus invicem disjunctis, intra cellulas rotundatas singulis, 

 sensim in nucleum validum, in media frond e nidulantem conjunctis con- 

 stituta, gemmidia plurima sine ordine distincto conglobate foventia 



* Ann. Jard. Bot, Buitenzorg, xxvii. (1900) pp. 68-71 (2 pis.). 

 t Bot. Gazette, xxx. (1900) pp. 393-9 (I pi.). 



t Continnatio v., Acta Univ. Lund, xxxv. (1899) 160 pp. and 3 pis. Cf. this 

 Journal, 1S99, p. 307. 



