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III.—On the Structure and Evolution of the Phyllodes in some Fossil Echinoidea

Published online by Cambridge University Press:  01 May 2009

Herbert L. Hawkins
Herbert L. Hawkins
Affiliation:
University College, Reading.
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Extract

In all the Regular Echinoids, with the exception of the Cidarids, and in the Irregular Echinoids other than the Clypeastroids and Spatangids, there is a tendency for the ambulacral plates to become crowded together as they approach the margin of the peristome. This is the inevitable result of the continuous formation of fresh plates at the edges of the oculars in the apical system, and their less rapid resorption at the opposite extremity of the ambulacrum. The compression of the ambulaeral plates results in a crowding of the pore-pairs in the peristomial region, and this character seems to serve a sensory as well as a motor purpose.

Type
Original Articles
Information
Geological Magazine , Volume 8 , Issue 6 , June 1911 , pp. 257 - 265
Copyright
Copyright © Cambridge University Press 1911

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References

Literature referred to

1872. Agassiz, A., “Revision of the Echini”: Mem. Mus. Comp. Zool. Harvard, vol. iii.Google Scholar
1909. Id., “On the existence of Teeth and of a Lantern in the genus Echinonëus, Van Phels ”: Amer. Journ. Sci., ser. IV, vol. xxviii.Google Scholar
1909. Bather, F. A., “Triassic Echinoderms of Bakony”: Result, wissensch. Erforsch. des Balatonsees, Band i, Teil i, Pal. Anhang, Budapest.Google Scholar
1869. Cotteau, G., Paléontologie Française: Terrain jurassique. Tome ix Eehinides irréguliers.Google Scholar
1900. Gregory, J. W.. “The Echinoidea” in Lankester's Treatise of Zoology, vol. iii.Google Scholar
1910. Hawkins, H. L., “Some Ambulacral Structures in the Holectypoida”: GEOL. MAG., N.S., Vol. VII.Google Scholar
1911. Id., “On the Teeth and Buccal Structures in the genus Connlus, Leske”: Treatise of Zoology, Vol. VIII.Google Scholar