Cackling goose Cackling goose The cackling goose ("Branta hutchinsii") is a North American bird of the genus "Branta" of black geese, which contains species with largely black plumage, distinguishing them from the grey "Anser" species. The black head and neck with white "chinstrap" distinguish this goose from all other geese except the larger Canada goose ("Branta canadensis") and the similarly sized barnacle goose ("B. leucopsis"). There are up to 5 subspecies of cackling goose, of varying sizes and plumage details. The female looks virtually identical but is slightly lighter and has a different voice. Some are hard to distinguish from the Canada
Polyphemus (crustacean) pairs of legs with exopodites, or outer branches. The legs are adapted for catching mobile prey, generally smaller species of water flea such as young "Daphnia" and "Bosmina". "Polyphemus" has two compound eyes that are fused to form a single unit, with a zoned set of receptors. This zoned structure is paired with an eye-control system that allows the "Polyphemus" to visually distinguish target size to avoid predators and track prey. "P. pediculus" is approximately in length. "P. exiguus", while similar in morphology, is smaller. Polyphemus (crustacean) Polyphemus is a genus of water fleas, and the only genus in the