ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 197 



and the views of various authors on the subject, are discussed. Carlson 

 himself considers that its allies are Apioci/stis, Tetraspora, and Htapfia, 

 which possess the same " pseudo-cilia " as Botryococcus, though in the 

 last-named genus they are considerably shorter than in the other genera. 

 Botryococcus is therefore regarded by the author as the most primitive 

 .and Apiocystis as the most highly developed of this group. 



Rhizoids of Mougeotia.* — A. A. Pascher gives an account of previous 

 work on the formation of the rhizoid-like outgrowths which occur on 

 Jlouyeotia, and describes the result of his own investigations on sterile 

 plants collected by him in Southern Bohemia. These appeared every 

 year in an artificial basin of water at the end of March and lasted for a 

 month, after which their place was taken by a species of Stigeoclonium. 

 The MougeoUa filaments developed a rich growth of rhizoids, and tlie 

 author describes in detail their manner of origin as well as that of the 

 •chromatophores which enter them from the main filament. He points 

 out that after the earliest stages the name " rhizoid " is incorrect for 

 these outgrowths, which with their chromatophores and cell-division are 

 really branches. He merely follows former writers in using the term. 

 He holds that they are, notwithstanding their frequent occurrence, an 

 abnormal growth and caused by outside influences. All attempts failed 

 to cultivate the alga under similarly abnormal conditions to those in 

 which the material examined was growing. 



Dunaliella.t — E. C. Teodoresco completes his morphological and 

 biological observations on this genus, and gives his reasons for maintain- 

 ing two distinct species, D. salina already known, and D. viridis a new 

 species. He finds that the former has zoospores with htematochrome 

 and no stigma, which produce red gametes reproducing the same type 

 of zoospore, while the latter, D. salina, is always green and always 

 possesses a red stigma. The exceptional conditions under which these 

 species can live is described, under the headings of dryness, temperature, 

 darkness, light, and concentration of water. The various experiments 

 of the author are described. 



Fossil Diatoms in New Jersey.^ — A. M. Edwards publishes an 

 account of fossil Diatoms discovered by him in the north-eastern part 

 of New Jersey in 1X1)0. He describes the geological position of the 

 deposit, and makes critical remarks on the species found there. These 

 point to the existence of a former lake, which was discovered inde- 

 pendently by the author, but had been already recognised by G. H. 

 Cooke, and called Lake Passaic. 



Navicula ostrcaria.§ — C. Sauvageau makes some interesting re- 

 marks on this Diatom, which has been studied by several authors and has 

 lately been recorded from the Mediterranean by Molisch. The author 

 deals with past work on the subject and with the history of species. 

 The Diatom is not confined to the shells of oysters (where, of course, it 



* Flora, xcvii. (1907) pp. 107-15. 



t Rev. Gen. Bot., xviii. (1906) pp. 409-27. 



i Nuov. Notar., xviii. (1907) pp. 39-48. 



§ Soc. Sci. Arcachon, ix. (1906) pp. 49-59. 



