These glands are represented externally by a special plate, the cribellum, which lies in front of the ordinary spinning mamillae, and by a comb of short bristles, the calamistrum, placed in the penultimate segment of the left of the last pair.
The tail may be a simple hollow muscular process or provided with stiff bristles set in transverse rows, or divided into two equally long processes, or finally it may form a large vesicular structure.
High, the surface divided into numerous furrows like the ribs of a melon, with projecting angles, which are set with a regular series of stellated spines - each bundle consisting of about five larger spines, accompanied by smaller but sharp bristles - and the tip of the plant being surmounted by a cylindrical crown 3 to 5 in.
High, composed of reddish-brown, needle-like bristles, closely packed with cottony wool.
(iv.) Trophi uncinate: Flosculariaceae; disk a contractile cup, often lobed, the cingulum of long vibratile cilia, of very long motionless bristles or absent, rarely with an outer zone of fine cilia.