Skip Navigation

This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrowRequest Permissions
Google Scholar
Right arrow Articles by GLEADALL, I. G.
Right arrow Search for Related Content
PubMed
Right arrow Articles by GLEADALL, I. G.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

J. Moll. Stud. (1989), 55, 479-487
© The Malacological Society of London 1989

research-article

AN OCTOPUS WITH ONLY SEVEN ARMS: ANATOMICAL DETAILS

IAN G. GLEADALL*

Visiting Research Fellow, Department of Physiology, School of Medicine Tohoku University 2-1, Seiryo cho Sendai, Japan 980

A male specimen of Octopus is described which has only seven arms: the fourth right arm is congenitally absent. Dissection reveals that, as in normal octopuses, eight brachial nerves arise from the brain. However, right brachial nerves 2, 3 and 4 are connected by unusually short lengths of the interbrachial commissure, distal to which right brachial nerves 3 and 4 run together, with corresponding arteries, into the third right arm. Hectocotylization of the latter confirms that it is the fourth right arm which is missing. Other abnormalities of the specimen include an obviously asymmetrical funnel organ and three pairs of conjoined suckers.

An old specimen of Octopus described as having only seven arms was re-examined for comparison. This animal, too, appeared to have no fourth right arm, but on closer inspection the extremely short stump of this arm was discovered.

*Present address: National Institute for Basic Biology, Nishigonaka 38, Myodaiji-cho, Okazaki 444, Japan

(Received 10 August 1988; accepted 1 November 1988)


Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?




Disclaimer: Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.