ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 591 



stjrax solution. He proved the existence of siliceous shells, 5 p.c. in 

 the mud of the stream, and 3 p.c. in the crusts and slimy coatings of 

 wooden objects. Some of the Bacillarie^ which live in the Bretter 

 canal of the pond have gelatinous sheaths which can withstand the 

 danger of drying up during the dry period when the sluice-gates are 

 shut. Species of Cymatopleura in the stream show an inclination to 

 saprophytism, for in their gelatinous sheaths are found other organisms. 

 Five new species and varieties are described. 



Sheath-forming Diatoms.* — M. Mobius describes instances he has 

 observed of two species of sheath-forming diatoms growing inside 

 the same sheath. He had previously published a note on this subject 

 in his "Algal Flora of Java" in 1893. In that case he found a 

 Scliizonema growing — sometimes isolated, sometimes in chains — among 

 the cells of Hommocladia. Now he describes the reverse case, a Hommo- 

 cladia among the cells of Schizonema. The material in which this 

 latter combination occurred was collected by Romer in a lake on the 

 island of Kildin, on the north coast of Lapland. Marine, brackish, and 

 fresh-water forms were represented in the collection. Among the diatoms 

 were specimens of Schizonema Grevillei, in the sheaths of which were 

 observed a small species determined as either Homoeocladia or Nitzschia 

 dissipata Grun. var. media. The distribution of this small species among 

 the Schizonema varied, and instances are figured. The author found also 

 another small species of Schizonema growing in the sheaths of S. Grevillei. 

 The author alludes shortly to his experiences in the staining of sheaths 

 of diatoms, and suggests the various effects of stains on different species 

 as an aid to identification. 



(Edogoniaceae.t — K. E. Hirn publishes a critical resume of the in- 

 vestigations and observations which have been made on ffidogoniaceae 

 in the years 1901-5, forming a supplement to the author's monograph 

 and iconograph of the order published in Act. Soc. Sci. Fenn. in 1900. 

 The present paper is divided into three sections : (1) The structm-e 

 and development of the CEdogoniace^e ; (2) new species, varieties, and 

 forms ; (3) list of species mentioned in literature, or otherwise observed, 

 since 1900, exclusive of new species. The first section deals with the 

 results obtained by various authors as regards cell-contents, cell-division, 

 germinating plantlets, oogonium malformations, the wintering of species 

 under cultivation without formation of oospores, and the influence 

 exercised by marine salts on the vegetation of certain species. To 

 the results of these authors Hirn adds his own observations. The 

 new species described since 1900 number 27 and 3 varieties, but the 

 author considers 20 only of these are good, 6 varieties and 2 new forms. 

 Complete information is now to hand about 0. pauJense and 0. j^seudo- 

 hoscii. The third section adds many new localities, and remarks to 

 species already recorded in the author's monograph. 



Algal Cells in Convoluta. %— F. Keeble and F. "W. Gamble have 

 made a study of the association of the green algal cell and the animal 



* Ber. Deutsch. Bot. GeselL, xxv. (1907) pp. 247-50 (figs.). 

 t Act. Soc. Sci. Fenn., xxxiv., No. 3 (1906) 63 pp., 4 pis. 

 X Quart. Journ. Micr. Sci., li. (1907) pp. 167-219 (2 pis.). 



