1905] CURRENT LITERATURE 229 
(one to four) into one, and after certain adjoining cells, called by him “nurse 
cells,” have gradually disintegrated and given up their chromatin to the forming 
spore. The first fusion is regarded as probably a sexual act, but he does not 
appear to attach this importance to the giving up of the chromatin by the “nurse 
cell.” His figures of the spores of Oscillatoria remind one of small hormogonia, 
while his ‘“‘nurse cells” evidently correspond to the cells adjacent to the hor- 
mogonia which have been heretofore regarded as collapsed, dead cells. 
The author makes a third distinct contribution, which is also far from con- 
vincing, in that he finds that the movements of the Cyanophyceae are caused by 
delicate cilia, distributed along the sides of the filament—Epcar W. OLIve. 
VULE of seven genera of cycads, Zamia, Macrozamia, Ceratozamia, 
10) 
Encephalartos, Bowenia, and Dioon, have been investigated by Miss Stoprs.'s 
The work was done in GorBEr’s laboratory and the standpoint is that of phylo- 
genetic anatomy. 
e integument in all the forms studied is differentiated into three layers, 
the outer and inner being fleshy, while the middle is the well-known stony layer. 
The inner system of bundles does not lie in the nucellus (which in all living cycads 
and their fossil relatives is absolutely without vascular bundles), or between the 
nucellus and integument, as is commonly supposed, but belongs to the inner 
fleshy layer of the integument. These bundles, which in all the seeds examined 
are similar and simple, sometimes extend beyond the nucellus, reaching almost 
to the micropyle. The larger ones are collateral and the phloem is not strongly 
developed. It is often hard to determine where the protoxylem lies, but, in general, 
the bundles are endarch. In the simplest case, these bundles come from the 
branching of a single concentric or nearly concentric bundle. 
The bundles in the outer flesh, with few exceptions, are collateral, with outer 
phloem and inner mesarch xylem. The central strand, from which these bundles 
come, is usually concentric. 
It is certain that the fossil seed, Lagenostoma, is related to living cycads. 
Evidence indicating this relationship is presented in detail and is illustrated by 
agrams. Miss Stopes believes that Lagenostoma lies near the common origin 
of the two groups. The single integument of the cycads is thought to correspond 
to the two separate integuments of Lagenostoma. 
It is particularly interesting to note that Cycas itself, generally thought to be 
the most primitive of the cycads, has the most highly developed seed to be found 
in the group.—C. J. CHAMBERLAIN. 
ZACHARIAS® adds another article to his long series of writings on the structure 
of the cyanophyceous cell, which leaves the subject in deeper uncertainty than 
ever. This latest addition is in the main a sharp criticism of the methods and 
_ 
*S STOPES, Marie C., Beitrige zur Kenntniss der Fortpflanzungsorgane der 
Cycadeen. Flora 93:435-482. figs. 37- 1904. 
*© ZacHarias, E., Ueber die Cyanophyceen. Jahrb. Hamburg Wiss. Anat. 21: 49- 
89. pl. 1. 1903. 
