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Fragmentation in the Genus Autolytus and in other Syllids

Published online by Cambridge University Press:  11 May 2009

E. J. Allen
E. J. Allen
Affiliation:
Director of the Plymouth Laboratory.
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Extract

In a former paper (Allen, Phil. Trans. Roy. Soc. B., Vol. 211, p. 131, 1921) it was shown that the Syllid Procerastea Halleziana Malaquin, addition to the ordinary mode of sexual reproduction which occurs in this group, reproduced asexually by a process of fragmentation, followed by the regeneration by each fragment of a new head and series of anterior segments and of a new pygidium and posterior segments. The fragments usually consisted of sections of two, three, or four segments each, in the region of the body behind the seventh setigerous segment. It was further shown that this breaking up of Procerastea, which could be produced artificially at any time by treating the worms with sea-water of low salinity, made by adding distilled water to natural sea-water, took place according to a definite law. The first section consisted normally of the head and setigerous segments 1 to 7, then followed three sections of two segments each (Segments 8 and 9; 10 and 11; 12 and 13), then three sections of three segments (14–16; 17–19; 20–22), followed by four or five sections of four segments each, and then a number of sections of three segments.

Type
Research Article
Information
Journal of the Marine Biological Association of the United Kingdom , Volume 14 , Issue 4 , May 1927 , pp. 869 - 876
Copyright
Copyright © Marine Biological Association of the United Kingdom 1927

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References

* Previous to the publication of my paper on Procerastea, Mesnil and Caullery, in a paper entitled “Sur un processus normal de fragmentation, suivie de régénération, chez une Annélide Polychète, Syllis gradlis Gr.” (Comptes rendus, t. 169, 1919, p. 926), which I had unfortunately overlooked, had described fragmentation followed by regeneration in Syllis gradlis. This case is described further in Mesnil, “Titres et travaux scientifiques (1893–1920),” Laval, Barnéoud, p. 37, and Mesnil et Caullery, “Sur la complexité du cycle évolutif des Annelidés polychètes ” (Comptes rendus, t. 178, 1924, p. 168). They did not, however, determine in Syllis gradlis the serial order of fragmentation, so that we do not know whether it resembles that found in Procerastea and in other Syllids to be described in the present paper. Since the publication of my Procerastea paper Dehorne (Comptes rendus, t. 178, 1924, p. 143) has described asexual reproduction in Dodecaceria.