On the Structure and Molt Controlling Function of the Y-Organ in the Prawn Penaeus indicus

The morphological and histological structure of the Y-organ of Penaeus indicus is described. The gland 1–2 × 0.3 mm (LXW) is located in between the mandibular and posterior dorsoventral muscle at the junction of prebranchial and branchial chambers. Histochemical tests were performed to determine the chemical nature of the Y-organ cells. Significant changes in the size and tinctorial affinity of the Y-organ cells were observed in relation to the molt cycle. Y-organectomy experiments revealed that the onset of premolt development was inhibited, suggesting the presence of molt inducing factor in the Y-organ.