Sea Urchins and Sand Dollars: Echinoidea - Physical Characteristics, Behavior And Reproduction, Sea Urchins, Sand Dollars, And People, Long-spined Sea Urchin (diadema Savignyi): Species Accounts - GEOGRAPHIC RANGE, HABITAT, DIET, CONSERVATION STATUS

Sea Urchins and Sand Dollars: Echinoidea - Physical Characteristics

Sea urchins and sand dollars are spine-covered sea animals with five arms and prickly skin. Most sea urchins are almost spherical and have five-way symmetry. Sand dollars usually are flat and have two-way symmetry. Sea urchins and sand dollars have rows of tube feet that run from the anus (AY-nuhs), which is on the top of the animal, to the mouth, which is on the bottom of the animal. At the top o…

Sea Urchins and Sand Dollars: Echinoidea - Behavior And Reproduction

Sea urchins move slowly and usually search for food at night to avoid predators. They use their teeth to bite and scrape their food. Sand dollars sift the sand for food while burrowing. Their spines are dense enough to prevent sand grains from falling through yet are fine enough to allow food particles to drop out onto strings of mucus before being placed in the mouth. Sea urchins and sand dollars…

Sea Urchins and Sand Dollars: Echinoidea - Sea Urchins, Sand Dollars, And People

Sea Urchins and Sand Dollars: Echinoidea - Long-spined Sea Urchin (diadema Savignyi): Species Accounts

Physical characteristics: The body of long-spined sea urchins is somewhat flattened and is about 3 inches (8 centimeters) in diameter. The long, thin, black or white spines are 2 to 4 inches (5 to 10 centimeters) long. The shell and spines are fragile. There is a shiny blue ring around the anus. Geographic range: Long-spined sea urchins live in the Indian Ocean and in the Pacific Ocean from Austra…

Sea Urchins and Sand Dollars: Echinoidea - Pea Urchin (echinocyamus Pusillus): Species Accounts

Physical characteristics: Pea urchins are one of the smallest urchins. The tiny egg-shaped shell is only about 0.6 inches (1.5 centimeters) long. These urchins are usually grayish green to bright green and have very short spines, which give the animal a velvety texture. Geographic range: Pea urchins live in the coastal waters of northern Europe. Habitat: Pea urchins live buried in gravel and sand.…

Sea Urchins and Sand Dollars: Echinoidea - Western Sand Dollar (dendraster Excentricus): Species Accounts

Physical characteristics: Western sand dollars have a rigid shell about 3.5 inches (9 centimeters) across and covered with moveable spines. These sand dollars are pale grayish lavender to dark purplish black. They have a five-way petal-shaped pattern of tube feet on the upper surface of the shell. Geographic range: Western sand dollars live along the west coast of North America from southern Alask…

Sea Urchins and Sand Dollars: Echinoidea - Six Keyhole Sand Dollar (leodia Sexiesperforata): Species Accounts

Physical characteristics: Six keyhole sand dollars are thin, flat disks with six slot-like holes and a five-way petal-like pattern of tube feet on the top side. They are about 4 inches (10 centimeters) across and are yellow to light brown. Geographic range: Six keyhole sand dollars live along the east coast of North and South America from North Carolina to Uruguay. Six keyhole sand dollars bur…

Sea Urchins and Sand Dollars: Echinoidea - Tuxedo Pincushion Urchin (mespilia Globulus): Species Accounts

Physical characteristics: The shell of tuxedo pincushion urchins is about 2.5 inches (6 centimeters) across and has five to ten broad bands of bright blue with bands of reddish brown spines. Geographic range: Tuxedo pincushion urchins live in the coastal waters of Asia from India to southern Japan. Habitat: During the day tuxedo pincushion urchins live among rocks and rubble as well as in crevices…