cribellum, kri-bel′um, n. an accessory spinning-organ of certain spiders—also Cribrell′um:—pl.
In the male the cribellum is rudimentary, and there is no calamistrum.
The cribellum in both these species is large and can easily be seen in front of the other spinnerets.
By means of the calamistrum these spiders comb from the cribellum a band of loose threads which form a part of their webs.
They have in front of the usual spinnerets an additional organ, which is named the cribellum (Fig. 102, c).
There are two quite distinct types of regular webs made by spiders possessing a cribellum and a calamistrum.
The cribellum (fig. 469) is sometimes covered by a fold of the skin, so that it is not readily seen.
The cribellum is large for the size of the spiders and can generally be plainly seen just in front of the other spinnerets.