ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 271 



On the retention of the power of germination by the spores of 

 alg8B very little is known ; but it is probable that they differ greatly 

 in this respect. 



The colour of seaweeds is probably of considerable physiological 

 importance. It is possible it may act like the colour of flowers, as an 

 attraction to those marine animals which assist in fertilization, and 

 also as a protection against those which are injurious. The same 

 purpose may also be served by the different taste and smell of different 

 species. 



Cystoseirse of the Gulf of Naples.* — E. Valiante publishes a 

 monograph of this genus. His investigations relate to the histology 

 of the alga and the classification of the species. The points specially 

 described are : The germination of the spores and formation of the 

 embryo ; the development of the vegetative organs of the embryo ; the 

 rhizoid processes, and radical disk ; and the sexual organs of reproduc- 

 tion. In the systematic part eleven species are described, one of them 

 new. 



Polysiphonia.f — L. Kolderup-Eosenwinge hn,s investigated the 

 structure of this genus of seaweeds, especially the species fastigiata, 

 nigrescens, and violacea. He confirms the statement of Schmitz that 

 cell-division does not take place either by a transverse septum or by 

 a longitudinal septum which includes the longer axis. The divisions 

 of the common basal cell of " branch " and " leaf" in P. violacea were 

 especially followed out and described. A peculiarity of the cell- 

 division in Polysiphonia and in some other Floridese is that the two 

 daughter-cells are of unequal size. It usually gives the impression 

 as if a smaller cell were cut off from a larger one, which remains 

 more or less entirely unchanged. The spiral arrangement of the 

 " leaves " is indicated already in the divisions of the apical cell. 

 The formation of the " branches " takes place in different ways in the 

 different species, pseudo-dichotomous, monopodial, or axillary. 



The antheridia and cystocarps are the result of metamorphosis of 

 the " leaves." The following is the mode of formation of the tetra- 

 spores in P. fastigiata. A large cell is first of all separated from 

 one side of the parent-cell. This divides into three cells by two 

 oblique, vertical, but not radial walls ; two of them on the outer side, 

 which behave like pericentral cells, a larger one on the inner side, 

 which is again divided by a horizontal wall into two cells, the upper 

 of which is the mother-cell of the tetraspores. 



Pithophora.J — F. Wolle records the interesting fact of the dis- 

 covery in several localities in New Jersey, U.S.A., of this singular 

 alga, hitherto known only in the tanks in the hot-houses at Kew, and 

 made, by its discoverer Dr. Wittrock, the type of a new order allied 

 to Confervaceee. 



* Fauna u. Flora des Golfes v. Neapel. vii. Monographic, 1883. Die 

 Cystoseiren, 30 pp. (15 pis.). 



t Bot. Gesell. Stockholm, Sept. 16, 1883. See Bot. Centralbl., xvi. (1883) 

 pp. 222-4. 



t Bull. Torrey Bot. Club, x. (1883) p. 13. 



