The Zoological Guide to Crustacea opens by providing an update on the cave crustacean decapods from Mexico, because in the last thirty years several species have been described. Mexico has diverse cave environments according to cave origin, such as: karstic caves, volcano caves with freshwater habitats and anchialine caves with marine and brackish habitats. The following study focuses on a total of 2,700 Artemia franciscana collected at the Al Wathba Reserve between December 2017 and May 2018, which were examined for the presence of larval helminths by direct microscopy of glycerin mounted specimens. Of these, 341 (= 12.6%) specimens contained different species of the Hymenopepididae and Progynotaeniidae families. The penultimate study investigates whether the non-marine ostracod Heterocypris incongruens can detect and react to chemical compounds derived from a predator and from injured conspecifics. The closing study demonstrates the diversity of larval phases and their importance to lobster populations and fisheries, and provides a summary of larval developmental patterns and behaviors and their potential impacts on larval dispersal and lobster demographic connectivity.