28 
Entwicklungsgeschichte — Physiologie 
is more probably a form of mitotic division dealing with a single large 
chromosome. • J. Ramsbottom (London). 
MC CORMICK, F. A., Development of the zygospore of Rhizopus 
nigricans [Prelimin. Notice] (Bot. Gaz. 1912, 53, 67—68). 
In the formation of zygospores in this species there is a streaming 
of protoplasm with nuclei into the young suspensors, followed by a denser 
accumulation at the contact ends of the suspensors. Before the suspensors 
are cut off, there appears a difference in the density and staining capacity 
of the protoplasm of the two suspensors, and this difference persists until 
the zygospore is mature. The walls, cutting of the gametangia from each 
other may not be formed simultaneously, and in each wall there is left 
a central pore. The wall separating the gametangia, thickens considerably 
before disintegration, and fragments of the thickened wall may be found 
in quite old zygospores. In the majority of zygospores the wall breaks 
down before any thickening occurs. The many nuclei from each game- 
tangium increase in size after the disintegration of the wall. All the 
nuclei except two disintegrate and these two nuclei are imbedded in a 
coenocentrum. There are certain indications that the coenocentrum has its 
origin at the point of contact of the two suspensors before the gametangia 
are cut off. Neither fusion nor division of the nuclei has yet been observed. 
From this stage to maturity many changes occur in the appearance of 
the zygospore, but their interpretation is not yet clear. The coenocentrum 
persists until quite late, and in the mature zygospore there are mamy 
nuclei of the same size as those in the mycelium. 
J. Ramsbottom (London). 
BESSEY, E. A., A suggestion as to the phyllogeny of the Hsco- 
mycetes (Science, N. S. 1913, 37, 385 [7. Mar.J). 
The author notes the similarity between the plant body and “spore 
fruits“ of the Ascomycetes and red sea weeds. Some red Algae lack 
chlorophyll and are parasitic on other Algae , suggesting the relation of 
Lichens to their host; both, likewise, having motile sperms. This indi¬ 
cates the development of Lichens from primitive parasitic red Algae; and 
from such Lichens have arisen the non-lichen Discomycetes, and perhaps 
through the closing and hardening of the apothecium also the Pyreno- 
mycetes. C. J. Humphrey (Madison, Wise.). 
PAVOLINI, A. F., L’ecidio della Pace ini a fuse a Relhan (Bull. Soc. 
Bot. Ital. 1912, 90—93). 
L’auteur étudie le développement de FAecidium du Puccinia fusca 
et spécialement Facte de la binucléation dans les écidiospores et les 
phénomènes qui précèdent et suivent cet acte. M. Turconi. 
BLAKESLEE, A. F., A possible means of identifying the sex of 
(+) and (—) strains in the Mucors (Science, N. S. 1913, 37, 
385 [7. Mar.]). 
The method consists in growing the (+) and (—) races of an iso- 
gamous dioecious species in contrast with a hétérogamie hermaphroditic 
species. A sexual relation has been found to occur between female 
