1971] 
Jackson — TVeb of Araneus 
29 
disks except that each thread is fastened to another thread rather 
than to a non-thread substrate. However, the number of strands 
(over 100, counting only those which touch the drag-line) at drag- 
line attachment disks (Fig. 9a) greatly exceeded the number at any 
connection from the web. Also, globules which, with the exception 
of one PS-R, were never observed on the minute strands of con- 
nections from the web, were found on some 0.5 /x — 1 [i thick 
strands at drag-line attachment disks (Fig. 9b). Are they involved 
in fastening the disks? What glands produce them? 
FORMATION OF JUNCTIONS 
How are threads fastened together at thread connections? By 
what mechanism is the junction formed? 
Within the glands, the silk is fluid. Eisner and Peakall (priv. 
comm.) have photomicrographs, taken under polarized light, of silk 
being pulled from the ampullate gland which indicate that the silk 
is already highly ordered at the spigot. Apparently the transforma- 
tion into a solid is at or previous to this point. Wilson (1969) 
hypothesized that the control valve, located inside the spinneret and 
behind the spigot, is the site of the transformation for the ampullate 
gland. 
One hypothesis for junction formation is that there is a cementing 
substance which fastens threads together. As the spinnerets touch 
the old threads, to which the new thread will be fastened, the 
cementing substance, from another gland, is added to the solid silk 
coming from the ampullate gland. If this hypothesis is true, then 
what is the cementing substance? Should we expect each type of 
connection to be equipped with the same type of cement? 
At SS-R’s, the cement is apparently not simply the viscid material 
from the aggregate glands. This conclusion is supported by two 
observations: 1) When SS-R’s were immersed in water, the globules 
on the SS were washed off; but the junction remained secure. 2) 
Artificial sticky spiral to frame connections and SS-R’s were pro- 
duced by placing a frame or radius over a Permount basin, then 
placing a SS from the same web across it. Never securely fastened, 
the SS at these connections could always be moved in any direction 
on the frame or radius. SS’s which cross but are not fastened to 
radii are common in the horizontal web of Uloborus diversus (Eber- 
hard, 1969), and we found them in webs of A. diadematus after 
the spider had ben administered a central stimulant (dextro-ampheta- 
