4 
The Ohio Naturalist. 
[Vol. VII, No. 1, 
cells of the hypocotyledonary region and root tip undergo rapid 
division so that the entire length of the cavity of the ovule is 
filled and the suspensor cells are crushed (Figs. 35, 37). But 
the vesicular cell retains its active appearance to the end. 
The plerome consists of a bundle of small elongated cells 
surrounded by a sheath of larger cells and the periblem consists 
of two layers with an inner limiting layer. The sheath of the 
plerome and the inner layer of the periblem have a common 
origin as will appear from an inspection of Figs. 36 and 38. The 
nature of these two layers was not determined. In the mature 
embryo the cotyledons are well developed but it is difficult to^ 
obtain central sections because of the curving and folding. 
Usually when one has a central section of the radicle the sections 
of the cotyledons will be more or less tangential. 
ADDENDUM. 
The foregoing paper was left in an incomplete condition at the 
time of my wife’s untimely death. It was her desire to work out 
the embryogeny of Bursa step by step as a preliminary to other 
embrvlological studies which she had begun. However, the 
work was so nearly complete that it was thought advisable to 
publish it as it was left although a few spindle stages are lacking 
for a complete series. Just before her last sickness she had pre¬ 
pared material collected at various times of the day and night 
in the hope of being able to fill out the missing stages. 
The series of figures, all drawn on the same scale, represent 
to the eye the actual increase of the embryo in size at each stage 
of development and will be of considerable use to students for 
reference. 
To be cut off in the midst of work and plans for the future 
was her sad lot, and, without referring to my personal loss, it is 
with a sorrowful heart that I contemplate her passing away so 
long before her bright hopes and ambitions were realized. 
John H. Schaffner. 
LITERATURE. 
1. Haxsteix, J. Entwickelungsgeschichte der Keime der 
Monocotvledonen und Dicotvledonen. Bot. Abhandl. Bonn, 
pp. 112,'1870. 
2. Famintzin, A. Embryologische Studien. Mem. Acad. 
Imp. Sci. St. Petersbourg 26:10, 1879. 
3. Riddle, Lumina C. The Embrvologv of Alyssum. Bot. 
Gaz. 26:314-324, 1898. 
4. Coulter, J. M., and Chamberlain, C. J. Morphology 
of Angiosperms. p. 196, 1903. 
5. Chamberlain, C. J. Methods in Plant Histology, p.. 
223. 1905. 
