THE SPINNING ORGANS. AT 
Somewhat different from the above are the spinning spools which are 
found on the anterior spinnerets. On these (Fig. 40) the bases consist of 
a short, more conical segment, which diminishes considerably from the 
broader base toward the free end. This conical basal joint, bj, is provided 
with a strongly concave end space. The terminal joint is almost double 
the length of the base, and is not straight as in the spools of the pos- 
terior spinnerets, but is a little curved. It stands in the centre of the 
concave end space of the basal cylinder. 
Dispersed among these smaller spools of the pyriform glands are 
shorter and thicker spools, sp, through which discharge the cylindrical 
and treeform glands, Fig. 35. Those belonging to the cylin- 
drical glands differ from those of the treeform glands in the 
character of the end space, which is in the former longer and | 
considerably thicker. In general, however, the construction of all these 
formations is similar. Figure 41 shows the discharging spigot of a cylin- 
drical gland, situated at the tip of the middle spinneret. This spigot like 
spinning tube consists of a basal piece, bj, formed by brown 
chitinous walls and a cylindrical end piece, tj, which Sepa 
more sharply towards the point. 
We are now better prepared to consider these beautiful \ 
instruments in their relation to their several silk glands. 
Close by the lower end of the spinning field of the pos- 
terior spinneret stands a large spool (Fig. 33, sp) into which 
leads a cylindrical gland. Farther above are the spools of 
two treeform glands, and close by are the two spools of two 
cylindrical glands. Besides these, innumerable spools of the “* , Ppeia die: 
pyriform glands cover the spinning field, and they are here 
all very long, especially those placed at the inferior position of the spin- 
ning field. 
On the spinning field of the middle spinneret stand many long spools 
which are connected with the pyriform glands. The number, however, is 
here less than on the other spinnerets. Just below these smaller 
spools, stands toward the upper side of the field (Fig. 24) a very 
large spool which is the mouth of a cylindrical gland. The 
point of the entire spinneret is formed by a rounded projection at the ex- 
treme end of the oval space, constituting the spinning field. On this none 
of the smaller spools stand, but only two larger ones, of which the one is 
the mouth of a cylindrical gland (ventricose of Meckel); the other gives 
exit to a tuberose gland. Besides these, there is also a short, solid horn of 
unknown use. The spinning field of the anterior or inner spinneret is 
covered with short small spools, whose number exceeds that of 
the other spinnerets. The chitinous epiderm which bounds the 
spinning field forms a zone not entirely closed, and in the open 
space is a horny cone (Fig. 25, sp.c) on whose point stands a spool of a 
Spigot 
Spools. 
Middle 
Spools. 
Anterior 
Spools, 
