In C. quadricarinatus, a microarray experiment comparing hepatopancreas gene expression in inter-molt versus pre-molt and post-molt animals indicated a reduction in the transcription levels of one hemocyanin gene in inter-molt, while another hemocyanin gene was most highly transcribed in inter-molt (Yudkovski et al., 2007). In the present study, hemocyanin was observed within the gastrolith matrix, showing a distribution pattern with seemingly higher concentrations of the protein along certain chitin-formed layers. The observed pattern could be due to changes in composition along the gastrolith vertical axis or perhaps fluctuations in the rate of layer formation and secretion of matrix ingredients from the forming epithelium. In addition, some protein may have been extracted during decalcification despite the use of fixative along with the decalcifying solution. Gastrolith formation and molting can be naturally achieved in juvenile crustaceans within a few days to 2weeks (as per our observations), a process that in adult crustaceans may take as long as 2months (Skinner, 1985). To date, there are no published data elaborating on the manner and/or rate in which gastrolith chitin layers are formed. In any case, it is a continuous process that requires fast maturation of each newly formed stratum while the next is already being secreted and, therefore, is likely to involve a set of hardening factors working in concert, including