494 Algae. — Fungi, Bacteria und Pathologie. 



division in the carpogonial cell provides one nucleus for the 

 trichogyne portion, and one (which subsequently fuses with 

 that of the sperm) which lies near the base of the lower 

 (carpogenous) portion. The antheridia are formed in radial 

 Clusters of foiir on the cells of the antheridial branches, and 

 each antheridium liberates a spermatium. This body is not the 

 definitial sperm, for when it becomes attached to the tricho- 

 gyne its nucleus undergoes mitosis, and it thus gives rise to two 

 sperms, each of which enters the trichogyne. The nucleus of 

 the iatter degenerates, as do those of the supernumerary sperms, 

 one male gamete passing through the narrow tubulär canal 

 that separates the trichogyne from the carpogenous cell. The 

 nucleus lying in the latter ascends to fuse with that of the sperm, 

 the process occuring in the region situated above the chroma- 

 tophore. Afterwards it descends again to the base, and there 

 undergoes mitosis. The first result of this division is the Sepa- 

 ration of a stalk cell, and then from the carpogenous cell of 

 the second order are budded out the gonimoblastic filaments. 



The nuclei of these cells all contain, so far as could 

 be ascertained, double the number of chromosomes cha- 

 racteristic of the Nemalion plant cells. The terminal cells of 

 the gonimoblastic filaments, at the divisions from which the 

 carpospores are definitely formed, is of a heterotype nature and 

 exhibits the reduced number of chromosomes. 



Owing to the fact that after a carpospore has escaped, the 

 subjacent cell may, and seems normally to, proliferate and 

 further that this process may be again repeatecl, it is difficult to 

 discover the exact relation of the heterotype mitosis to spore 

 formation. The author however concludes that some of them 

 at least are formed directly on its termination, and if this is 

 correct it would indicate that at any rate for this plant, it is 

 certain that the reduction is truly effected by the heterotype 

 division. But it would be of interest to follow, if possible, the 

 Steps of mitosis at the first division of the carpospore. Should 

 the whole reduction process be effected by a Single heterotype 

 mitosis, it would represent a shortening of the process as com- 

 pared with that elsewhere encountered in plants and animals, 

 although the essential function (that of reduction) would be se- 

 cured. It is at any rate clear that so far as the nuclear pheno- 

 mena are concerned, the evidence, as afforded by Nemalion, 

 indicates that in the red seaweeds a true alternation of gene- 

 rations exists. It is obvious however that further investigations 

 on tetraspore-forming members of the group are urgently 

 needed. J. B, Farmer (London). 



BOUDIER, Icones Mycologicae. Serie I. Livraisons 2 et 3. 

 Sept. et Dec. 1904. 



Les 40 nouvelles planches publiees par la librairic Klincksieck 

 presentent les caracteres de precision scientifique et de beaute artistique 

 signales ä propos de la premiere livraison (Bot. Centr. XCVI. p. 328). 



