About Hapalogaster cavicauda Stimpson, 1859
Hapalogaster cavicauda is a flattened, crab-like crustacean. It reaches a maximum carapace width of 20 millimetres (0.79 in), and its body is covered in setae, also called hairs. Hairs on the species' third maxilliped filter plankton from water for food; the species also feeds on algae scraped from rocks. Female Hapalogaster cavicauda carry their eggs on the tail during winter.
This species is found along the Pacific coast of North America. Its range extends from Cape Mendocino in the north, through the Channel Islands, to Isla San Jerónimo, Mexico in the south. It typically lives beneath rocks in the lower intertidal zone. The related species H. mertensii is found further north, and shares a similar ecology with H. cavicauda.
