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V.—Note on Actinocamax, Miller; Its Identity with Atractilites, Link

Published online by Cambridge University Press:  01 May 2009

G. C. Crick
Affiliation:
British Museum (Natural History).

Extract

In a paper entitled “Observations on Belemnites,” which was communicated to the Geological Society of London in April, 1823, J. S. Miller defined the genus Belemnites thus: —“A cephalopodous? molluscous animal provided with a fibrous spathose conical shell, divided by transverse concave septa into separate cells or chambers connected by a siphuncle; and inserted into a laminar, solid, fibrous, spathose, subconical or fusiform body extending beyond it, and forming a protecting sheath.” In May of the same year Mr. Miller contributed to the same Society another paper in which he instituted the genus Actinocamax for “spathose bodies which resemble the belemnitic guard in general appearance, but are distinguished from it by presenting, instead of the terminal cavity intended for the reception of the chambered shell, a protruding and convex base.”

Type
Original Articles
Copyright
Copyright © Cambridge University Press 1904

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References

page 407 note 1 Report on Cornwall, 1839, p. 83.

page 407 note 2 Trans. Roy. Geol. Soc. Cornwall, xii (6), 1903, p. 406.

page 407 note 3 Trans. Geol. Soc., ser. II, vol. ii, pt. 1 (1826), pp. 45–62.

page 407 note 4 Ibid., pp. 63–67.

page 408 note 1 The term ‘alveolus’ is here used for the chambered part of the shell, but this is now known as the phragmocone, the term ‘alveolus’ being applied to the conical cavity in the guard that receives the phragmocone.

page 408 note 2 As Link's work is very rare we have thought it advisable to give the description in Link's own words; it is as follows:—

Atractilites. Atractilit. Eine spindelförmige, inwendig strahlig krystallisirte Schale, ohne Alveole.

A. belemniticus. Belemnitischer Atr. Die spindelförmigen Belemniten werden von vielen Schriftstellern angeführt, aber oft verwechselt uud nicht genau beschrieben. Wir besitzen an beiden Enden völlig zugespitze Exemplare. An dem einen bemerkt man deutliche Spuren einer blättrigen Textur, sonst sind sie den gewöhnlichen Belemniten ganz ähnlich. Ich habe ein Stück zerschlagen und iuwendig die strahlige Bildung der Belemniten aber durchaus keine Alveole gefunden, daher man sie nicht zu der vorigen Gattung bringen kann.”

page 408 note 3 Gümbel, C. W.: “Geognostische Beschreibung des bayerischen Alpengebirges,” etc., 1861, p. 475.Google Scholar