THE SPINNING ORGANS. 
43 
SOE 
Ppigterss 
op este A 
Roe te 
Fic. 35. Three forms of spinning glands opening into the posterior spinneret, spn. The middle one 
enlarged in different proportion from the others. py.g, a group of pyriform glands. b.du, a bundle 
of ducts opening into the spinneret through the spinning field, SF. tr.g, treeform gland; tr.d, 
excretory duct with brownish glandular walls or boundaries, bs; cy.g, cylindrical gland; tu, its 
tubular part; am, ampullate expansion of the same; b.du, beginning of duct from the ampulla ; 
c.du, cylindrical duct; do and k, the noose shaped twist of the duct continued in an external 
envelope, n.w, derived from the ampulla. 
