Spadix (zoology)


In the field of zoology, a spadix (/ˈspdɪks/ SPAY-diks; plural spadices /ˈspdɪsz/ SPAY-dih-seez, /spˈdsz/ spay-DY-seez) is a secondary sexual organ found in some cephalopods and hydrozoans. In the genus Nautilus, the spadix is a composite erectile organ in the male located in the oral region which is composed of four highly modified tentacles and which is paired with a somewhat smaller antispadix that is also composed of four tentacles. The spadix is normally a concealed organ but quickly becomes distended upon the animal's death. The exact function of the spadix and antispadix in Nautilus is not yet known.[1]

Diagram of the mouth of an adult male Nautilus pompilius. AS, antispadix; B, buccal mass; CS, cephalic sheath composed of the fused sheaths of the digital tentacles; O', preocular tentacle; O'', postocular tentacle; S, spadlx; SLL, superior labial lobe; V, Van der Hoeven's organ.

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  1. ^ Arthur Giese (2 December 2012). Reproduction of Marine Invertebrates V4: Molluscs: Gastropods and Cephalopods. Elsevier Science. p. 233. ISBN 978-0-323-15305-8.