1898] CURRENT LITERATURE st3 
peculiar (mesarch) type of vascular bundle as has long been known to occur 
incycad leaves. Mesarch bundles are found in certain fossils of cycadean 
stock (Bennettiteee, Medullosez), in the leaves of Cordaitez, which like recent 
cyeads had normal stem bundles, and in Lyginodendron and Poroxylon.. 
Dr. Scott's discovery establishes a new link between the Cycadacez and the 
Lyginodendrez and, coupled with the occurrence of mesarch bundles in these 
palozoic plants, makes it probable that this kind of bundle formerly occurred 
in the stems as well as leaves of cycads. He thinks the loss has been due 
to the early and increasing development of secondary tissues from the 
cambium. 
Mr. W. H. Lang® has investigated the microsporangia of Stangeria 
The nearly mature sporangium has a wall five or six cell-layers 
thickness, and the spore mother cells are immediately invested by three 
differentiated layers. The inner layer is the tapetum, which is not distinguish- 
able till the sporangium is well grown, and then arises from the sporogenous 
mass. The other two specialized layers are derived from the sporangium 
wall and consist of flattened cells. The archesporium was not traceable to 
asingle cell, but was a plate of four cells derived by a periclinal division of 
four large hypodermal cells.—W. R. SMITH. 
THE RADICAL DIFFERENCE of opinion regarding bacterial structure which 
* present exists among investigators who, like Biitschli and Fischer, are 
rea conversant with the subject-matter, naturally makes all interpretations 
the observed facts appear more or less in the light of odzter dicta, and one 
the latest contributions to this interesting discussion can hardly escape 
Placed in the same category with the others. Meyer, nevertheless, 
Sata problem a far richer contribution of fact than is contained in 
recent polemical deliverances. 
i bacterium (regarded by Meyer as a new species, and named 
cally “gaa ra), wwaich was found upon boiled carrot, afforded espe- 
of very high : oaeral for investigation, and the author claims that the use 
greatly tie magnifications, combined with carefully chosen peace niypete 
itions in wi ae study. The spore of Astasia germinates under ae 
and subdiy; . vA six hours, and gives birth to a motile rod which divides 
ay into new motile forms. After about twelve hours some of 
a. individuals come to rest, secrete a gelatinous envelope, and 
tods in the aay although continuing to divide. Some, but not all, of these 
quiescent stage become sporangia, as Meyer terms them, and each 
"Studies j F 
int sin the development and morphology of cycadean sporangia. Annals 
* 421-438. 18 7 
brings 
Bot 
fy . 
"ART ; : 
der cay Myer. Studien iiber die Morphologie und Entwickelungsgeschichte 
%4: 185-24 — an Astasia asterospora A.M. und B. tumescens Zopf. Flora 
ee 
