ON ARACHNIDA. 
443 
towards their extremity, they terminate in a straight thread, 
leading to the nipples, which are cylindrical or conical parts, 
and membranaceous, serving as a conduit to the threads of 
silk, which are named spinnerets. 
The mygalge have but four apparent nipples, the upper two 
of which form a small forked tail ; but in the others they are 
six. In these the nipples have but two articulations, the last 
of which, in the form of a head, is bordered all round, like a 
crown, with several conical pieces, which give issue to the 
silken threads, and are in fact the spinnerets properly so 
called. 
The proper spinnerets of each nipple are carried by some 
authors to the number of a thousand, so that, when all the 
nipples are at work, the quantity of threads which proceed 
from them should be six thousand. But these animals manage 
with economy a substance which constitutes a portion of their 
means of existence, and which is also necessary to the preser- 
vation of their posterity. Moreover, this calculation is not 
applicable to all the species, since many of them form no web, 
and employ their silk only in the construction of the cocoon, 
which is to envelope their eggs. 
It has been attempted, by weaving, to derive some advantages 
from the silk of certain of the araneides of the genus epeira, and 
gloves and stockings have been made of this silk, of a greyish 
colour, almost as strong as those fabricated with the ordinary 
silk. Lebon employed that of the cocoon of these animals, 
and thirteen ounces of these cocoons yielded four ounces of 
silk. To put it into a state for being wove, he caused it to be 
beaten with the hand, and with a small stick, for the purpose 
of expelling the dust; he afterwards washed it in tepid w r ater, 
and put it then into soap-suds, in which some saltpetre and 
gum-arabic w T ere dissolved. The w hole w r as kept boiling over 
a slow fire for two or three hours, and the cocoons after this 
operation were washed in tepid water, until they yielded to 
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