There is an oval neural gland of brown colour lying immediately above the brain. It is embedded in the mantle in the intersiphonal region and is 4 × 1 mm in size. It has several branching tubules, which open in a non-ciliated canal running along the entire length of the gland.
It leads into a short duct which opens by a ciliated funnel at the base of the dorsal tubercle in between two lobes. Nephrocyte cells of the blood collect waste particles, mainly xanthine and urates. They enter the lumen of the neural gland from where they pass out into the pre- branchial zone of pharynx. The neural gland also secretes a hormone which aids in oviposition and metamorphosis.
Thus, the neural gland is probably homologous with the pituitary gland of vertebrates.
