sinus gland

The sinus gland is a small, glandular mass found in the eyestalks of crustaceans. It has an endocrine function and is analogous to the neurohypophysis in vertebrates. This gland, along with the X-organs in the optic ganglia, produces neurohormones that regulate various crustacean functions.12

These neurosecretions control pigment movement in chromatophores for body color changes and also affect the retina. Crucially, they regulate molting and associated metabolic processes by influencing the Y-organ. Unlike insects, crustaceans have an inhibitory neurosecretion that controls the Y-organ's molting hormone production. The sinus gland is a key component of the crustacean endocrine system, impacting color, vision, and growth cycles.2