ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
595 
geneous ; as soon as it becomes reticulate, the large nucleus contains a 
vacuole and two nucleoles. The network of protoplasm subsequently 
disappears ; the whole of the protoplasm becomes applied to the cell- 
wall, and is denser at the apex of the spore, where several nuclei make 
their appearance, and the first free-cell-formation takes place. The 
first’septation at the apex of the spore occurs simultaneously with the 
appearance of protein-granules, and advances gradually towards its base. 
No diaphragm was observed in any case. The terms primary and 
secondary prothallium are not applicable to the different zones of the 
protliallium of Selaginella. The extine and intine are formed from a 
single protoplasmoid shell of the spore ; subsequently the intine divides 
into two layers. 
Stem of Selaginella.* — Prof. R. J. Harvey Gibson has made a com- 
parative study of the stem of fifty-three species of Selaginella; and 
groups these, according to their anatomical structure, into eight sections, 
which do not correspond to the divisions of the genus ordinarily adopted 
and derived from morphological characters. These sections are grouped 
round the eight species — S. leevigata , sjoinosa , Galeottii, Braunii, oregana , 
Martensii, uncinata , and insequalifolia. 
The author calls attention to the fact that the structure of the 
ascending is often different from that of the procumbent stem. He retains 
the term epiderm for the limiting layer of cells, although it is destitute 
of stomates and has lignified cell-walls ; the sclerotized tissue lying 
immediately below it is the stereome or liypoderm. As endodermal cells 
he designates the cuticularized cells which arise from the chlorophyl- 
laceous layer surrounding the phloem ; the term trabecule is used in a 
general sense for the unicellular or multicellular strands which anchor 
the vascular cords to the cortex ; a trabecule may he merely an endo- 
dermal cell. The term pericycle is retained for the green layer or 
layers which give origin to the endodermal cells and enclose the phloem ; 
the elements occurring within it constitute the protophloem ; for the 
parenchymatous layer next the xylem he proposes the term phloem- 
parenchyme. The term vascular bundle is used to indicate a leaf-trace 
only ; stele being retained for the vascular strand enclosed within a 
pericycle and endoderm. 
Bulbs of Cystopteris bulbifera.f — According to Herr F. Matouschek, 
the adventitious buds of this species differ in structure from those which 
occur in other ferns, and present a greater resemblance to the bulbils of 
Flowering Plants. They consist of fleshy scales which are of a foliar 
character, and do not develope either fronds or roots while still attached 
to the parent plant ; they germinate only when they have reached the 
soil, after having been thrown off by the drying up of their basal portion. 
Fossil Salvinias.J — Mr. A. Hollick finds a number of remains of 
fossil Salvinias in a deposit from Washington Territory, U.S.A., and 
establishes from them one new species, S. elli^tica. 
Position of Sphenophyllace3e.§ — From a fresh examination of the 
various fossil forms comprised under SphenojoJiyllum and Trizygia, Herr 
* Ann. Bot., viii. (1894) pp. 133-206 (4 pis.), 
t Oesterr. Bot. Zeitschr., xliv. (1894) pp. 121-4, 177-8 (1 pi.). 
x Bull. Torrey Bot. Club, xxi. (1894) pp. 253-7 (1 pi.). 
§ Ber. Deutsch. Bot. Gesell., xii. (1894) pp. 97-100 (3 figs.). 
