These are the sea
spiders, around 1,300 species have been described; all are marine. They are
usually less than 6 cm in body length, but can have legs over 30 cm long. Most have
two pairs of simple eyes and no gaseous exchange system, so diffusion of gases and wastes occurs over the body surface. Their mouth is located at the end of a sucking proboscis.
have four pairs of walking legs, and the males have an additional pair of small
legs called ovigers (see Nymphon rubrum right) which they use for carrying the developing eggs. There can be 1000 eggs in an egg mass.
They are found in all oceans, but are most abundant in Polar regions.