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III.—Fossil Representatives of the Lithodomous Worm Polydora

Published online by Cambridge University Press:  01 May 2009

F. A. Bather
Affiliation:
Brit. Mus. (Nat. Hist.).

Extract

The borings of the Polychæt Annelid Polydora ciliata (Johnston) are familiar in limestone pebbles and the stouter mollusc-shells on our coasts, but shales and occasionally other rocks are not free from their attacks. They may be recognized by the double aperture, often loosely described as keyhole-shaped, leading to a U-shaped cylindrical tube. The union of the two apertures in a single depression, by the loss of the organically formed septum between them, produces a more slit-like opening, whereas if the surface of the pebble be further worn the two round holes are more clearly distinguished. The differences between the burrows of Polydora and those of other lithodomous Annelids, especially the associated Dodecaceria, were clearly stated by Dr. W. C. M'Intosh in a very full paper “On the Boring of certain Annelids” (1868, Ann. Mag. Nat. Hist. [4], ii, pp. 276–95, pls. xviii–xx).

Type
Original Articles
Copyright
Copyright © Cambridge University Press 1909

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References

1 I have to thank my colleague, Dr. W. T. Calman, for kindly referring me to this species and some recent papers on it.

2 The relations of Polydora to recent oysters have been fully discussed by Professor M'Intosh ( 1902, Ann. Mage. Nat. Hist. [7], ix, pp. 299308Google Scholar).