This project sought to better understand neuropeptide signalling across the moult cycle within crustaceans and provide a basis for future work on endocrine control of crustacean ecdysis. RNA was extracted and sequenced from the central nervous system (CNS), Y organ (YO), and epidermis of the European Shore crab, Carcinus maenas, across the moult cycle. Transcriptome assemblies of CNS and YO were done separately and differential gene expression analysis were done to discover neuropeptides and their putative neuropeptide receptors and to identify changes in their gene expression across the moult cycle. A third transcriptome was assembled, consisting of YO and epidermis from inter-moult crabs, to identify putative neuropeptide receptors specific to the YO, the only known role of which is the synthesis of ecdysteroids.