160 Miscellaneous. 
sion of its cells, by which means the epidermis itself ceases to exist 
as such. 
Consequently the outermost layer of cells on the surface (of a 
root-envelope consisting of several layers of cells) is not the epidermis, 
but is to be regarded, from its mode of production, as equivalent 
to all the other “layers. The cells of this layer may grow out into 
radical hairs in all plants, but these are frequently produced only 
when the roots adhere to foreign bodies. The hairs are often rami- 
fied and variously thickened, and may be unrolled, in many plants, 
in spiral bands. 
In every root-envelope many cells are perforated when old. This 
may be proved anatomically in many cases, and may always be de- 
monstrated by injection with insoluble colouring-matters. 
The layer of cells situated beneath the root= -envelope, and called 
the “ endodermis”’ by Oudemans, cannot, in accordance with its 
developmental history, be regarded as epidermis. Fissure-like ori- 
fices are never seen in it; and when such have been supposed to be 
seen, this depends upon an illusion produced by the section, The 
endodermis is present in the aérial roots of all Orchideze, and never 
lies on the surface. It always consists of two kinds of cells—namely, 
elongated cells the outer walls of which at least are thickened, and 
shorter cells which are always thin-walled. The latter always have 
a remarkably large nucleus; the walls of the cells of the root-enve- 
lope adjacent to them are usually thickened in a different manner 
from those which cover the elongated cells of the endodermis. When 
the root-envelopes consist of but few series of cells, there is over 
these a group of variously formed cells which may be described as 
covering-cells (Deckzellen). 
The cortical parenchyma, the thickened ring, and the medulla 
present peculiarities in the mode of thickening of their cells which 
we do not meet with in the aérial roots of plants of other families. 
The aérial roots of many Aroideze likewise possess a root-envelope 
agreeing precisely, both in structure and development, with that 
occurring in the Orchideze. The aérial roots of the Cactez, on the 
contrary, are destitute of a root-envelope.—Bericht der Akad. der 
Wiss. zu Wien, May 12, 1864, p. 87. 
Description of a new Mustela from Quito. 
By Dr. J. E. Gray, F.R.S. &c. 
Mr. Gould has transferred to the British Museum the skin of a 
small Mustela, received from Quito, which is very distinct from any 
we have previously seen. Itis about the size of the European Weasel. 
MustTELA AUREOVENTRIS. 
Dark brown; chin and side of the throat white; throat, chest, 
inside of fore legs, and belly golden yellow; whiskers black; tail 
rather tapering, as long as the body ; the soles of the hind feet hairy ; ; 
the pad of the toes bald, callous, hairy on the sides; ears rounded, 
hairy. Length of body and head 6 inches, of tail 44 inches. 
Hab, Ecuador, Proc. Zool. Soc. Feb. 9, 1864. 
