HORSESHOE SHRIMP

any member of the marine crustacean subclass Cephalocarida, named because of the curving, horseshoelike shape of the body. A few species are known, the first of which was described in 1955. A very primitive group, the horseshoe shrimp have no eyes; in addition, appendages occur only on the thorax, or midsection. They are hermaphroditici.e., functional reproductive organs of both sexes occur in the same individual. Hutchinsoniella macracantha, which attains a length of 37 mm (1.5 inches), occurs on the Atlantic coast of northeastern United States. Lightiella incisa, about 2.6 mm (0.10 inch) in length, is found in waters near Puerto Rico; L. serendipita, 3.2 mm (0.13 inch) long, occurs in San Francisco Bay on the coast of California. Sandersiella acuminata, 2.4 mm (0.094 inch) long, is found in waters near Japan and New Caledonia.