626 
Algae. — Eumycetes. 
at high magnifications. (The Journal of the Quekett mierosco- 
pical Club. ser. 2, Vol. 10, N°. 62. p. 243—246. 1908.) 
When photographing very translucent diatoms at high magnifi¬ 
cations it is difficult to obtain sufficient contrast between the object 
and the background. This is due to too small a difference between the 
index of refraction of the mounting medium and that of the silex 
of the diatom. Better results are obtainable with styrax than with 
Canada balsam; better again with monobromide of naphthalin; and 
best of all with realgar. Secondly it is very difficult to obtain a 
sharply defined photograph of the minute details of the diatom. 
These finer details when much enlarged appear as if they are 
mounted in fog in the photograph. Owing to optical difficulties there 
is a halo round each dot; the fog is the result of the overlapping 
haloes. The author describes how by the use of suitable photogra- 
phic plates, coated with rapid and slow emulsions respectively,. 
the fog may be more or less eliminated. A negative is taken on a 
rapid plate; from this a positive is made on rapid plate; and from 
this a second negative on a slow plate. The explanation of how and 
why success is obtained is given by the author. E. S. Gepp. 
West, G. S., Botanical Synonyms in the Desmidiaceae and 
Protococcoideae. (Journal of Botany. XLVII. London, p. 60—64. 1909.) 
This is a series of criticisms and corrections of determinations 
in a paper by C. Bernard upon Protococcacees et Desmidiees d’eau 
douce, recoltees ä Java (Dep. de l’Agriculture, Batavia. 1908. 230 pp. r 
16 pls.). Bernard enumerated 326 species and varieties, and illustrated 
them with 580 figures. He described two new genera and eighty-seven 
new species and varieties, and appended a bibliography of ninety- 
three works. West complains of the inaccuracy of many of Ber- 
nard’s figures and of the absence of many necessary side and 
vertical views. He also complains that Bernard apparently has 
omitted to consult sundry important works on the Desmids of 
Britain, tropical Africa, South America, Koh Chang and 
Burmah. West first reduces or condemns thirty of Bernard’s new 
species, and then points out the inaccuracy of some forty-five other 
determinations. E. S. Gepp. 
Hagem, O., Untersuchungen über norwegische Mucori- 
neen. I. Chria. (Videnskabs Selskbs. Skrifter. I. Math-naturv. 
Klasse. 7. 1907. Christiania. 1908. 50. pp. with 22. figs. in the text.) 
The author has undertaken to examine the fungi of the air and 
the soil; but for the thorough examination of the biology and phy- 
siology of the fungi it is necessary first to clear up their systematic 
Position and therefore the author gives in this first part a mono- 
graphic review of the species of the Mucorineae , he has isolated 
from the soil and the air, remarking, that these fungi are not to be 
classified according to their morphological qualities only, but that 
the physiological qualities too are necessary for their proper Classi¬ 
fication. The author describes how he caught the Mucoraceae of the 
air by placing Petribowles in town and wood. Even the germs, 
caught at - 23° were able to germinate. The Mucoraceae of the 
soil he cultivated by spreading a small grain of earth or decayed 
wood on Agar in a lot of Petribowles. He has found 16 species 
of Mucoraceae in the soil, viz: Mucor racemosus Fres., Mucor hie- 
