466 
Algae. — Eumycetes. 
d’origine neritique. On peut y arriver en colorant par un melange 
de Rosazurine G et d’azurine brillante en presence de potasse caus- 
tique. Apres refroidissement on traite par une solution de sulfate de 
cuivre ä 0,5°/ 0 . La paroi des kystes apparait coloree en rose ou en 
rouge, tandis que la carapace des Peridiniens Test en bleu. 
Pour les Diatomees l’hematoxyline alunee vieille (preparee depuis 
6 mois au moins) donne de tres bons resultats, surtout si l’on fait au 
prealable macerer le plancton pendant 24 heures dans une solution 
de Vanadate d’ammonium au centieme. Les materiaux fixes ä l’acide 
chromique ne peuvent etre utilises: la membrane reste incolore. 
II est interessant de faire remarquer que le plancton traite par 
l’alcool est presque toujours melange ä des matieres mucilagineuses 
dont l’ensemble offre une tres grande ressemblance avec des mas- 
ses plasmiques. Ce sont sans doute ces depöts qui ont ete pris 
pour du protoplasme extramembraneux dont la presence a servi ä 
etayer la theorie ingenieuse de l’accroisement centrifuge. 
P. Hariot. 
Fraser, H. C. J., Contributions to the Cytology of Humaria 
rutilans Fries. (Annals of Botany. XXII. p. 35—55. pl. IV & V. 
1908.) 
The author continuing her series of investigations on the deve¬ 
lopment of Ascomycetes has followed the life history of this form. 
The ascocarp originates apart from any ascogonium or antheridium 
in a mere tangle of septate hyphae. In this tangled mass, the hypo- 
thecium of the young ascocarp, the nuclei are seen to be of two 
sizes and the smaller nuclei fuse in pairs, thus giving rise to the 
larger. Migration of nuclei seems to take place, though rarely, in 
connexion with these fusions. There is thus a process of reduced 
fertilization or apogamy, as these fusions of vegetative nuclei 
replace the normal sexual union. The cells containing the fusion 
nuclei give origin to the ascogenous hyphae; nuclear division in 
these hyphae show 16 chromosomes. The divisions in the ascus were 
closely studied. Düring the first mitosis fusion of the two nuclei in 
the ascus occurs and at this time the separate spiremes already show 
evidence of a longitudinal fission. 
The first and second divisions are considered as heterotype and 
homotype respectively. The stages described by Farmer and Moore 
in the meiotic phase of animals and plants were observed during 
these divisions and the same interpretation is placed upon them. 
In the heterotype division reduction occurs and 16 chromosomes 
appear. Since there is no evidence of the union of the spiremes 
of the two fusing ascus nuclei it may be supposed that each conti- 
nues its development separately, and each independently breaks up 
into the reduced number of chromosomes. The 16 chromosomes 
would thus represent two sets of postmeiotic chromosomes This 
number is retained during the second division. The third division is 
of particular interest for in the early prophase the 16 chromosomes 
appear; but they separate without Splitting, leading to a second re¬ 
duction to eight chromosomes, the post-meiotic number. To this 
new, simple type of reduction, which is not associated with a con- 
traction of the chromatin, the term brachymeiosis is applied. It is 
suggested that the physiological difference between ordinary meiosis 
and the simple brachymeiosis may be in the fact that the former 
in its associated contraction allows of the mingling of chromatin 
