THE 
SPINNING ORGANS. ai 
The spinnerets articulate 
obliquely from the outer side 
and the front, inward and 
backward, so that their tips 
approximate the correspond- 
ing spinning fields of the mid- 
dle spinnerets. The base is 
covered on both of its side 
faces with many rows of bris- 
tles (Fig. 25, b); it is divided 
from the terminal field by a 
suture, su, and a brown chit- 
inous zone, z. ‘The terminal 
joint is cap-shape, and is only 
partially occupied as a spin- 
ning field. 
On the top of the spinning 
field are from sixty to seventy 
very short spinning spools, 
sss, and a spinning spigot, 
connected with a cylindrical 
gland, Fig. 25, sp.c. The base 
of these spigots is surrounded 
by a pair of chitinized stripes, 
which originate in the chit- 
inous zone, z Close to this 
place is inserted a very strong 
a 
Sy 
Fic. 25. Anterior spinneret, magnified largely. z, brown chit- 
inous zone that bounds the spinning field; sw, sinew of the 
bending muscles of the anterior spinning wart; du.c, duct 
from cylindrical spinning glands; sp.c, spigot discharging cy- 
lindrical gland; sp.t, spigot of treeform gland; s.ss, spinning 
spools of pyriform glands. (Bucholz and Landois.) 
and long sinew, sw, which unites with the chitinous border of the spin- 
ning field at the furrow (su) between the base and the terminal joint. 
This sinew passes beyond the root of the spinneret into the strong, motor 
a c 
Fig. 26. View of the spinning spools of 
Argiope cophinaria, as they appear in 
clusters. a, short spools; c, long spools; 
b, a small cluster; tj, terminal joint; 
bj, basal joint. 
muscle, ms, which controls the movement of 
the spinneret towards its fellows. Within the 
bases of the spinnerets are bundles of muscles 
which contribute both to the general move- 
ment of the spinneret and to the movement 
of the individual spools on the tip. On the 
chitinous edge of the spinning field is a single 
row of strong bristles, br. 
On examining the spinnerets with a lens 
of ordinary power, the tips or spinning fields 
are found to be covered with a great number 
of fine movable spinning tubes, already men- 
tioned, known as spinning spools (Fig. 26), 
which are regularly disposed over the surface. 
