Brady_, on the Seed of Didyoloma Peruviana. 65 
fections of object-glasses, this result led to a definite opinion 
as to the quality of the power employed. 
I will only add, that when combined with the hemispherical 
condenser and the whole series of eye-pieces, the new half-inch 
is a battery of microscopic powers, and will be a good substi- 
tute, in case of slender purses, for the To^ti, -^th, -^th, and 
other fractions. I may therefore be permitted to congratulate 
our society on the valuable results consequent upon the 
attainment of almost unlimited aperture, combined with per- 
fect flatness of field, in powers as low as the \ and -poth; and 
let it not be forgotten, that English opticians still take the 
lead in these improvements, w^hich should yield honour as well 
as profit to themselves. 
On the Seed of Dictyoloma Peruviana, D.C., &c. 
By Hy. B. Brady, F.L.S. 
(Read June 12th, 1861.) 
There are few points of greater interest to the micro- 
scopist, or that better repay his attention, than the external 
character of the seeds of plants. Many, from their mere 
superficial beauty, have become popular show-objects ; but a 
deeper interest is awakened, and an almost boundless field 
of investigation is suggested, by such phenomena as those pre- 
sented by the peculiar spiral cells of the testa of Collomia, 
Ruellia, or Salvia; the curious hairs from the seeds ofCobsea 
or Acanthodium ; the beautiful surface markings on those of 
Papaver, Lychnis, or Silene; the coma of Hoya and other 
Asclepiads ; or the membranous wings so common amongst 
the Bignoniaceae. That there are many new and valuable 
facts to be gathered from a systematic study of these 
structures, no one who has given much attention to them 
can doubt, and I only regret that my own observations^ 
though extending over a considerable time, have as yet been 
too desultory and disconnected to be of much practical 
value. Recently, however, a specimen was placed in my 
hands so peculiar in some of its characters that I have 
thought it might properly form the subject of a short 
notice. 
The seed of Eccremocarpus scaber, a half-hardy climbing 
plant, common in our gardens, is familiar to most as a 
microscopic object ; but as an acquaintance with this will 
