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Notes on some Fossil Echinoids

Published online by Cambridge University Press:  01 May 2009

Th. Mortensen
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Extract

For a long period it was customary to base Echinoid classifi-cation exclusively on the characters of the test alone. It was not until the beginning of this century that other characters were also taken into consideration, starting with my work on the “Ingolf” Echinoidea I, 1903, in which I pointed out that characters of great classificatory value were found also in the structure of the pedicellariae and spicules. Through using these characters it was found that the numerous forms of Regular Echinoids, referred on account of the great uniformity of their test-characters to some few large “genera”, e.g. Echinus, Strongylocentrotus, Cidaris, in reality belonged to a number of various generic types, even to different families. In the following year, 1904, in my “Siam” Echinoidea, I pointed out that also the structure of the teeth was of primary classificatory importance, this being further worked out by Jackson, 1912, in his Phytogeny of the Echini, where the characters of the whole dental apparatus were found to afford characters of the greatest importance, and where the excellent names Aulodonta, Stirodonta, and Camarodonta were coined, names which will have to be adopted in Echinoid classification.

Type
Original Articles
Information
Geological Magazine , Volume 71 , Issue 9 , September 1934 , pp. 393 - 407
Copyright
Copyright © Cambridge University Press 1934

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References

page 398 note 1 After this paper had been written I received from Professor Alph. Jeannet, Zurich, a “Note sur un Miocidaris nouveau” (B. Peyer, “ Die Triasfauna der Tessiner Kalkalpen. VI,” Abh. d. Schweiz. Pal. Gesellsch., liii, 1933), in which is described a Miocidaris hescheleri n. sp. from a single specimen, preserved with its spines, much like the present specimen. It is, however, very different from the English Miocidaris, by the character of its ambulacra, spines, and particularly by having a series of large, crenulate tubercles outside the primary interambulacral tubercles. Jeannet makes it a subgenus of Miocidaris, Serpianotiaris, leaving it undecided whether it should perhaps rather form a separate genus. There can, in my opinion, be no doubt but that it should really form a separate genus. This outer series of tubercles, as also the absence of a collar on the primary spines, and the unusual character of the ambulacra, distinguish it so markedly from Miocidaris that one might, indeed, be tempted to suggest that it should perhaps rather form a separate family.

page 401 note 1 A figure of such a spine is given in Wright’s Monograph of the British Fossil Echinodermata from the Cretaceous Formations, p. 74, fig. 3. I am indebted to Mr. Brighton for calling my attention to this figure, which I had overlooked.Google Scholar

page 403 note 1 The description of the lantern of this specimen will be given in Part II of my Echinoid Monograph.