48 AMERICAN SPIDERS AND THEIR SPINNINGWORK. 
cylindrical gland, the only larger gland which dis- 
charges here. On the inside of this horny cone 
is attached a long yellowish cord or point, upon 
which strong muscles are inserted in order to 
move the cone against the spinneret. 
Mr. Underhill figures the spigots or large spin- 
ning tubes which issue upon the posterior and 
anterior spinnerets.! The former are situated upon 
the interior margins and are connected with two 
very large glands which are doubtless the cylin- 
drical glands as heretofore described. These spig- 
ots are shown at Fig. 43 together with a portion 
of the ducts leading to their appropriate glands 
(not represented) which lie below the pyriform 
glands. Fig. 44 shows one of these anterior spig- 
ots, a.sp, compared with two spools ss. of the same 
spinneret. Mr. Blackwall announced the 
Fic. 43. Anterior spinneret of 
Epeira diademata. (After Un- 
derhill.) ss, spinning spools; 
sp, spigot; py.g, pyriform glands 
with their ducts, py.d. The 
glandular epithelium is repre- 
sented. cy.d, ducts belonging 
to the spigots; sp, probably of 
Spools 
Vv fact for the first time, so far as I know, 
ary. 
that the spools vary greatly in number 
in different species, and also differ considerably in 
size not only in individuals of the same species, 
but often even on the same spinnerets. The larger 
species of the Epeiroids have the spinnerets most 
cylindrical glands; cy.g. amply provided with spools, and Blackwall ex- 
presses the opinion that the total number does not greatly exceed a thou- 
sand, even in adult females of Epeira quadrata, whose weight is about 
twenty grains, and in many other /\ 
species it is smaller. 
As illustrating the difference in 
various genera it may be stated that 
_—— 
ss. 
i ‘ 
Fi. 44. a.sp, spigot on anterior spinneret of Epeira dia- 
demata leading to cylindrical gland; ss, spools of pyri- 
Tegenaria domestica and 
form glands, same spinneret. (After Underhill.) > 165. 
Numbers 
rT ES A 
egenaria civilis, for ex- 
Vary. Bene ; 
ample, have less than four 
hundred spinning spools each. In 
Textrix agilis and Lycosa saccata 
the number is below three hundred. 
In Segestria senoculata it scarcely 
exceeds one hundred, and in many 
of the smaller spiders it is still 
further reduced. 
The difference in the number and size of the spools connected with the 
several parts of the spinnerets in the same species, and with similar pairs 
in different species, is also very apparent. In spiders constituting the 
1Science Gossip, 1874, page 181. 
