1. Crangon handi, new species. is described and compared with five other California crangonid shrimps; it occurs from the littoral zone to 55 m from Sonoma County to Bahia Colnett. northern Baja California. Crangon handi is a specialist for shallow-water coarse sand substrates and here exhibits remarkable crypsis. Crangon handi eats small gammarid amphipods and has in turn been found in the stomach of the thornback skate.2. Lissocrangon, new genus, is proposed to accomodate C. stylirostris, a species lacking gastric spination; Crangon is restricted to shrimp with one gastric spine; Steiracrangon Kinahan, is revived for shrimp with bicarinate sixth abdominal segments; and Neocrangon Zarenkov is revised and amended to include shrimp with two gastric spines and bicarinate sixth abdominal segments.3. Morphological analyses and relative growth are presented and discussed for all six crangonids considered. Crangon handi and L. stylirostris are squat shrimps in restricted habitats probably adapted for short quick bursts of movement followed by rapid reburial: the remaining four species are relatively elongate and habitat generalists.4. Crangon species normally occurring on finer mud and sand bottoms are unable to achieve the degree of crypsis of the coarse-grained species, Crangon handi. Crangon handi from dark coarse-grained sediments is only partially able to adapt to light coarse-grained sediments.5. Crangon nigromaculata is the only species with a lateral color spot, and it is suggested that this may serve as a predator shock signal or target decoy analogous to similar markings in some fish.6. Fish, such as cottids, and macrocrustaceans, including C. handi and the sphaeromatid isopod, Tecticeps convexus, sympatric with it on coarse sand bottoms, exhibit a wide range of mechanisms apparently to escape detection and avoid predation. Tecticeps alone has at least six such mechanisms. This suggests that predation pressure in such habitats may be relatively high.