penetration gland

penetration gland

[‚pen·ə′trā·shən ‚gland]
(invertebrate zoology)
A gland at the anterior end of certain cercariae that secretes a histolytic substance.
References in periodicals archive ?
Hugghins (1954) described the life cycle of Hysteromorpha triloba (Rudolphi, 1819) whose cercaria is similar to Furcocercaria XIX in the morphology of the penetration gland cells, presence of three circles of spines surrounding the opening of the ventral sucker, number and position of sensory hairs on the body (one pair) and several pairs in the tail stem, resting position, size of the body (168-221/41-50 H.
However, both cercariae differ in having fewer penetration glands (4 pairs) and lacking an incomplete transverse commissure.
Seven pairs of penetration gland cells are located between the pharynx and the posterior part of body, with a thick granular content.
Penetration gland cell ducts are visible, but not their glands.