Onchnesoma

Description

The species of this genus are usually small in size (with a trunk of less than 1 cm in length). The introverted is much longer than the trunk. The body wall muscle layers presents continuous. The disc may present oral tentacles (usually less than 10 and about 8 mm. in length) arranged around the mouth, but those tentacles can be reduced in size or completely absent. The retractor muscle system is a highly modified introverted form fused to form a muscle retractor. The anus is located in the distal half of introverted. Gallbladder contractile is rarely observed and if present is without villi. They have a single nephridium.

Species

• Onchnesoma intermedium Murina, 1976
• Onchnesoma magnibathum Cutler, 1969
• Onchnesoma squamatum (Koren y Danielssen, 1875)
• Onchnesoma steenstrupii Koren y Danielssen, 1875

References

References

1. Stephen, A. C., and. Edmonds S. J. (1972): The Phyla Sipuncula and Echiura. vii+528 Trustees of The British Museum of Natural History. London. {{ISBN. 0-565-00717-3
2. Ditadi, A.S.F. & Migotto, A.E. (1982): O Filo Sipuncula. Concelho Nacional de Desemvolvimento Cientifico e Tecnologico CNPq Brasilia. 43p.
3. Cutler, Edward B. & Cutler, Norma J (1985): A revision of the genera ''Phascolion'' Théel and ''Onchnesoma'' Koren and Danielssen (Sipuncula). Proceedings of Biological Society of Washington 94(4):809-850
4. Cutler, Edward B. & Gibbs, Peter E. (1985): A Phylogenetic analysis of higher taxa in the Phylum Sipuncula. Systematic Zoology 34(2):162-173.
5. Cutler, Edward B. (1994): The Sipuncula: their systematic, biology and evolution. Comstock Publishing Associates of Cornell University. Ithaca, New York. 406p {{ISBN
6. Cutler, Edward B. (1973): Sipuncula of the Western North Atlantic. Bulletin of American Museum of Natural History, 152(3):103-203.
7. Gibbs, Peter E and Cutler, Edward B. (1987): A classification of the phylum Sipuncula. Bulletin of the British Museum (Natural History) Zoology, 52(1):43-58
8. Murina, V.V. (1976): New and rare species of sipunculida from the East China Sea. Vestnik Zoologi, 2:62-67
9. Cutler, Edward B. (1969): New species of Sipuncula from western North Atlantic. Proceedings of Biological Society of Washington, 82:209-218.
10. Smithsonian National Museum of Natural History. Antarctic Invertebrates: Onchnesoma magnibathum Cutler, 1969 http://invertebrates.si.edu/antiz/taxon_view.cfm?ScreenWidth=1003&ScreenHeight=567&taxon=8585&MODE=taxon
11. Koren, J. and Danielssen, D.C. (1875): Bidrag de norskr Gephyreens Naturhistorie. Nytt. Magasin for Naturvidenskapene, 21:201-138.