What's the difference between spinneret and spinnerule?

Spinneret

Definition:

(n.) One of the special jointed organs situated on the under side, and near the end, of the abdomen of spiders, by means of which they spin their webs. Most spiders have three pairs of spinnerets, but some have only two pairs. The ordinary silk line of the spider is composed of numerous smaller lines jointed after issuing from the spinnerets.

Example Sentences:

(1) The proximal region of the gland is capable of protrusion through the prothoracic sternal slit as an elongate organ reaching upto the spinneret.
(2) PC12 cells, an immortalized cell line which secretes large amounts of dopamine, and dissociated bovine adrenal chromaffin cells, a non-dividing cell type which also secretes dopamine, were coextruded by a dry-jet wet spinning technique through a double-lumen spinneret from a 15% weight by volume solution of poly(acrylonitrile vinyl chloride) in either dimethylsulphoxide (DMSO), dimethylacetamide (DMAC) or dimethylformamide (DMF).
(3) Two others, called MoonLightPath and Spinneret, "are planned to be added by September 2013."
(4) The detection of a special mechanoreceptive field on top of the anterolateral spinnerets increases the knowledge of the functional morphology of the spider's spinning apparatus.
(5) They are formed of seven cells: a principal unpaired secretory cell which produces an abundant glycoproteinaceous secretion; a small associated cell with a secondary reservoir for this secretion; two accessory secretory cells which have very abundant tubular extensions coming from the plasma membrane, and a flocculent secretion gathered in a large sub-cuticular space; two cells forming an enlarged part of the excretory canal, functioning like a spinneret; and finally a single cell forming the tubular duct of this complex gland.
(6) The spinnerets of these two animals were also examined by scanning electron microscopy.