The squid are a part of kingdom Molluska class Cephlodia. Squid are mainly found in the order Teuthida. Their primary orders are Myosophina and Ogosophina. Only Cephlopoda can change color. Only Cephlopoda have closed circulatory systems. They have approximately 300 species. They only live in salt water. They are found in two ocean zones – euphotic through the disphotic zones – ranging from about 30 feet to 1000 feet. The squid can swim 25 body lengths per second. Squid are the fastest among the invertebrates. Their fins on the out side of the body help stabilize the squid. The squid have a funnel on theirback called a siphon. The mantle sucks the water in, and the siphon pushes it out to help the squid move. They swim in schools of four to 30. There have been large numbers of squid in the Gulf of Mexico, Hawaii, and California. Squid are mostly caught around the United States. They are eaten by whales, birds, and bony fish. Squid eat plankton, snails, small, fish, and large mammals. The squid use the tentacles to grab their food. They do not use their arms for this. They have ten arms encircling their beak and the two long tentacles. The tentacles have hooks and suckers. Even the baby squid have tentacles. They are the same as their parents. A female can produce thousands of eggs and stores the eggs in her ovary. The male sperm is produced in the testis and stored in a sack until he releases it in the water where it will fertilize the eggs. Myosophids are nertic while the Ogosophids are benthic. When adult, the largest squid is 90 cm the smallest one is 14 cm.