Aspidosiphonidae

Aspidosiphonidae is a family of peanut worms. It is the only family in the monotypic order Aspidosiphonida, which is in the class Phascolosomatidea.

Description
The family Aspidosiphonidae is characterized by an oval disk with short tentacles, arranged in a crescent-shape made of an enclosed nuchal organ. It has a canal of sacs in the coelom, lying in a continuous band. The anal and caudal shield (at the anterior end) are both made up, not of chitin, but of a horny protein. It is of note that most, but not all, of the Aspidosiphonidae family has a caudal shield. The family also has two nephridia.

Aspidosiphon

 * Aspidosiphon albus Murina, 1967
 * Aspidosiphon coyi de Quatrefages, 1865
 * Aspidosiphon elegans (Chamisso and Eysenhardt, 1821)
 * Aspidosiphon exiguus Edmonds 1974
 * Aspidosiphon fischeri Broeke, A. ten, 1925
 * Aspidosiphon gosnoldi Cutler, E., 1981
 * Aspidosiphon gracilis (Baird, 1868)
 * Aspidosiphon laevis de Quatrefages, 1865
 * Aspidosiphon mexicanus Murina, 1967
 * Aspidosiphon misakiensis Ikeda 1904
 * Aspidosiphon muelleri Diesing 1851
 * Aspidosiphon parvulus Gerould, 1913
 * Aspidosiphon planoscutatus Murina, 1968
 * Aspidosiphon spiralis Sluiter, 1902
 * Aspidosiphon steenstrupii Diesing, 1859
 * Aspidosiphon tenuis Sluiter, 1886
 * Aspidosiphon thomassini Cutler and Cutler, 1979
 * Aspidosiphon venabulum Selenka & Bulow, 1883
 * Aspidosiphon zinni Cutler, 1969

Cloeosiphon

 * Cloeosiphon aspergillus (de Quatrefages, 1865)

Lithacrosiphon

 * Lithacrosiphon cristatus (Sluiter, 1902)
 * Lithacrosiphon maldivensis Shipley 1902