176 
THE CABINET OF NATURAL HISTORY 
the only alterations perceptible in their external condition 
were a small decrease in bulk, and a slightly wrinkled ap- 
pearance, particularly of the abdomen: but their functions 
were seemingly unimpaired; for on warm days, or when 
excited by artificial heat, they were lively in their mo- 
tions, and to the last continued to produce their threads, 
which were often destroyed for the purpose of ascertaining 
whether they would be replaced by others with apparently 
the same facility as at the time of their capture. 
It is particularly deserving of notice, that these insects, 
though unable to climb up the smooth perpendicular sides 
of the phials on their first introduction, soon contrived to 
traverse the interior of their prisons in eyery direction. 
In order to illustrate their manner of proceeding on this 
occasion, the case of an individual has been selected for de- 
scription, — the same method, with a few trivial modifica- 
tions, being pursued by all. Elevating the abdomen, and 
pressing the spinning-apparatus against the side of the 
phial, this spider emitted from its papillae a little viscous 
fluid, which on exposure to the air hardened into a minute 
semi-transparent speck; then moving to a short distance, 
and drawing out a thread after it, one end of which re- 
mained fixed to the spot it had connected this filament 
with another part of the phial by applying the spinners as 
before. Several lines being thus produced, the spider 
speedily raising itself upon them above the bottom of the 
phial, promoted its undertaking by repeating the process 
just described; every step so gained enabling it to carry its 
operations still higher. 
From the cylindrical figure of the phial, it follows that 
all the lines attached to its sides by their extremities, such 
as were vertical alone excepted, formed with those sides 
chords to arcs of various magnitudes. Lowering itself from 
one of these chords to another, and applying the spinners 
to each in succession, the spider soon connected the whole 
of them together by a line; then ascending again to the 
greatest altitude it could attain, and dropping down by a 
thread to the bottom of the phial, over which it walked to 
the opposite side; it there drew the thread tight and made 
it fast, having prevented it from coming in contact with 
the glass previously by raising the abdomen a little. To 
this oblique line it united others, extending them in differ- 
ent directions, till by these means it established a commu- 
nication with every part of the phial. As there was some 
difficulty in tracing these operations with the unassisted 
eye, lenses of the magnifying powers of six and eight were 
employed. 
The spiders seen ascending into the atmosphere on the 
1st of October were of two distinct species; but as the 
technical difference of insects has engaged only a small 
share of my attention, I shall leave the task of identifying 
them to those who are more familar than myself with this 
branch of entomology. The subjoined remarks on some 
of the characteristics of these insects, which are more con- 
veniently illustrated by the pen than the pencil, may serve 
to facilitate this object. 
One species has four of its eight eyes much larger than 
the other four. Two pairs situated in the front or fore- 
part of the head are arranged thus °. , the relative size of 
the dots being nearly the same as that of the eyes. The 
other pair of small ones is placed in the upper part of the 
head, and on each side of it one of the remaining pair of 
large eyes is seated. The spider has the abdomen rather 
depressed; the anterior limbs, which it raises in a menacing 
manner when any thing approaches it, are longer than 
the posterior ones; and it moves in a lateral direction with 
almost as much ease and expedition as it does straight 
forward. The largest individuals of this species observed 
to be conveyed through the atmosphere by a current of 
air acting upon their lines, measured one-sixth of an inch 
between the extreme points of the head and abdomen; one- 
tenth of an inch across the broadest part of the abdomen; 
and weighed about a quarter of a grain. 
The second species has also four eyes of a greater magni- 
tude than the other four. The arrangement and relative 
size of three pair placed in the fore-part of the head may 
be thus expressed by dots ; one of the other pair of 
large eyes being situated on each side of the head. Spi- 
ders of this species have the last pair of legs longer than 
the first, and move with great celerity, but rarely in a 
lateral direction. They vary considerably in colour, some 
being of a much darker hue than others, and these are fre- 
quently without the pale longitudinal line which extends 
the whole length of the thorax, and sometimes even on 
to the abdomen of the lighter-coloured specimens. The 
largest individuals seen floating in the air were somewhat 
inferior in weight and dimensions to the largest of the pre- 
ceding species observed under similar circumstances*. 
Trans. Linn. Soc. 
* Is this the Aranea dorsalis of the Siistema Naturae, Gmelin’s Edit.? 
FOUNTAIN TREES. 
The Fountain Trees are very extraordinary vegeta- 
bles, growing in one of the Canary Islands, and likewise 
said to exist in some other places. Of these remarkable 
trees, we have the following account in Glasse’s History of 
the Canary Islands: “ There are only three fountains of 
water in the whole island of Hiero, where the Fountain 
Tree grows. The great cattle are watered at those foun- 
tains, and at a place where water distils from the leaves of 
