The whole of this surface appears to be active in the secretion of a mucous-like substance.
To the right (in the figure) of the rectal peduncle is seen the deeply invaginated shell-gland ss, with a secretion sh protruding from it.
It has been proved that the secretion contains a digestive ferment capable of rendering proteid matter soluble.
The lid is especially attractive to insects from its bright colour and honey secretion; three wings lead up to the mouth of the pitcher, on the inside of which a row of sharp spines points downwards, and below this a circular ridge (r, fig.
The musky odour from which it derives its name is due to the secretion of a large gland situated in the inguinal region, and present in both sexes.