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On a Hermaphrodite Specimen of Amphioxus with Notes on Experiments in Rearing Amphioxus

Published online by Cambridge University Press:  11 May 2009

J. H. Orton
Affiliation:
Naturalist at the Plymouth Laboratory.

Extract

A hermaphrodite specimen of Amphioxus has been taken at Plymouth having one gonadial pouch filled with ova and the remaining pouches filled with sperm. This specimen closely resembles a similar one taken by Goodrich at Naples.

The liver and intestine of the Plymouth specimen are abnormal, but no parasites have been identified in the tissues to account for these abnormalities.

It is, moreover, improbable that there is any normal sex-change in Amphioxus, since three independent investigators have found very small specimens of both sexes, therefore no satisfactory explanation can be given of the occurrence of hermaphroditism in the specimen.

Amphioxus have been found to spawn in June, and larvae have beenobtained from the captive specimens.It is suggested that the club-shaped gland may secrete a substance for attaching the larva of Amphioxus to objects, and that this function may be correlated with the asymmetry shown in the early development of the Amphioxus .larva.

Type
Research Article
Copyright
Copyright © Marine Biological Association of the United Kingdom 1914

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References

* I am indebted to Mrs. Orton for the drawings for Figs. 1 and 2, and for assistance with that for Fig. 3; and also to Mr. E. Ford for the lettering of the Figures.

* M. Legros, “Sur la Morphologie des Glandes sexuelles de l'Amphioxus lanceolatus,” Comptes-Rendus du Troisième Congrès Internationale de Zoologie, Leyden, 1895.

* P. Langerhans, Archiv f. Mikr. Anat., Bd. XII, 1876, p. 326.

Goodrich, E. S., “A Case of Hermaphroditism in Amphioxus,” Anat. Anz., 42 Bd, 1912.Google Scholar

Leiber, L. Neidert u. A., “Uuml;ber Bau und Entwicklung der Weiblichen Geschlechtsorgane des Amphioxus,” Zool. Jahrb., Bd. XVIII, 1903.Google Scholar

§ Zarnik, B., “Uber die Geschlechtsorgane von Amphioxus,” Zool. Jahrb. Abt. Anat., Bd. XXI, 1905.Google Scholar

* With regard to the occasional hermaphrodites among fishes it may be remarked that it is highly important to know the size and also the age of specimens—which are usually omitted from descriptions—if the data are to be useful for investigating the life-history of the fish.

* The actual time was not recorded, but it was some time between 11 a.m. and 4.30 p.m.

B. Hatschek, “Entwicklung des Amphioxus,” Arb. Zool. Inst. Wien., 1881, Vol. IV.

A. Willey, Amphioxus and the Ancestry of the Vertebrates, 1894, p. 172.