ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 77 



have already appeared in the "Journal de Botanique." In the present 

 volume he continues his treatment of Halopteris, and deals with Phlceo- 

 taulon and Ptilopoyon. He includes twelve species in the genus Halo- 

 pteris, and for the convenience of students he draws up two keys, one 

 for naming fertile and the other sterile specimens. Several species 

 hitherto known under other generic names are here placed in this genus. 

 Phlccocaulon contains three species, and the author shows the charac- 

 teristics which distinguish it from the genera Chmtopteris and Halopteris. 

 Ptilopogon is only begun, and one species is described, P. botryocladus 

 Reinke. The work is to be continued. A bibliographical index is 

 given of the memoirs quoted. 



Cytology of Nemalion multifidum.* — J. J. Wolfe fills with this 

 paper a gap in our knowledge of the cytology of Florideas. He divides 

 his paper into four sections : A. Methods. B. The cell. C. Matura- 

 tion and sexual reproduction. D. Mitosis. Under the cell he treats 

 of (a) the structure of the chromatophore ; (b) division of the chroma- 

 tophore. The third section is divided into (a) oogenesis ; (b) spermato- 

 genesis ; (c) fertilisation and development of the cystocarp. The fourth 

 section consists of (a) the nucleolus; (b) reduction. The chromato- 

 phore is present in all cells of the plant, except the mature antheridium 

 and the two sperm-cells to which it gives rise. It is in the form of a 

 hollow ellipsoid, from which processes radiate to the periphery of the 

 cell and there flatten out to form a clathrate membrane. The sex- 

 organs cannot be regarded as unicellular structures, and the reasons 

 for this are detailed. In the nucleus the entire chromatin content is 

 stored in the nucleolus, and, in the prophases of division, passes to the 

 nuclear wall along delicate fibrilhc. The spindle is intra-nuclear, and 

 centrosomes are distinctly visible at the poles at metaphase. The author 

 concludes that Nemalion presents the essentials of an antithetic alter- 

 nation of generations, and that the cystocarp is therefore the homologue 

 -of the sporophyte in higher plants. This conclusion he bases on the 

 fact that approximately sixteen chromosomes are present in the divisions 

 of the cells of the cystocarp up to the period of spore-formation, and 

 approximately eight in those of the thallus ; the reduction division 

 being immediately associated with the production of the carpospores. 



Chantransia Alarise.t— This species, which has hitherto only been 

 recorded from Iceland and the Faeroes, has now been found by 

 J. Adams at Portrush, co. Antrim, growing on the lamina of Alaria 

 esculenta. It differs from the type in being somewhat smaller and in 

 having alternate and not opposite monosporangia. Neither antheridia 

 nor cystocarps were observed. Hairs were not found terminating the 

 filaments, though they may have been present earlier in the year. 



Rhipidosiphon and Callipsygma.J — A. and E. S. Gepp give an 

 account of these two rare monotypic genera, both of which have been 

 placed in Codiacere. In the original description of Rhipidosiphon javensis 

 by Montague, the plant is described as being fan-shaped, with dicho- 



* Ann. Bot.. xviii. (1904) pp. 607-27 (1 fig. in text), 2 pis. 



t Journ. Bot. xlii. (1904) pp. 351-2. % Tom. cit.. pp. 363-6 (1 pi.). 



