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III.—The Ventral Integument of Trilobites1

Published online by Cambridge University Press:  01 May 2009

Charles E. Beecher
Affiliation:
For. Corr. Geol. Soc. Lond., Yale University, New Haven, Conn., U.S.A.

Extract

In previous papers by the writer on the structure and appendages of Triarthrus, no attempt has been made to describe or illustrate the character of the ventral integument, especially in the sternal or axial region. The specimens hitherto described were prepared to show details of the appendages, and though portions of the ventral membrane were exposed in many individuals, the subject was not considered of sufficient moment to warrant a distinct study, particularly as no characters were observed in the cuticle that had not been previously seen in more or less perfection by Walcott in the genera Ceraurus and Calymene. A recent discovery by Jaekel, however, necessitates the separate consideration of this structure. This necessity arises from the fact that a positive addition to the knowledge of the trilobite anatomy may be deduced, although, as will be shown, Jaekel was apparently entirely misled in his interpretation of the nature of his discovery.

Type
Original Articles
Copyright
Copyright © Cambridge University Press 1902

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Footnotes

1

Reprinted by permission from the Amer. Journ. Sci. [4], vol. xiii (1902), pp. 165-174.

References

page 152 note 2 Beecher, C. E., “On the Thoracic Legs of Trilobites” : Amer. Journ. Sci. [3], vol. xlvi (1893)Google Scholar. On the Mode of Occurrence, and the Structure and Development of Triarthrus Becki”: Amer. Geol., vol. xiii (1894)Google Scholar. Appendages of the Pygidium of Triarthrus”: Amer. Journ. Sci. [3], vol. xlvii (1894)Google Scholar. Further Observations on the Ventral Structure of Triarthrus”: Amer. Geol., vol. xv (1895)Google Scholar. The Morphology of Triarthrus” : Amer. Journ. Sci. [4], vol. i (1896)Google Scholar; Geol. Mag., Dec. IV, Vol. III (1896)Google Scholar.

page 153 note 1 Walcott, C. D., “The Trilobite: New and Old Evidence relating to its Organization” : Bull. Mus. Comp. Zool., vol. viii, No. 10 (1881)Google Scholar. Appendages of the Trilobite”: Science, vol. iii, No. 57 (1884)Google Scholar.

page 153 note 2 Jaekel, Otto, “Beiträge zur Beurtheilung der Trilobiten,” Theil i: Zeitschr. Deutsch. Geol. Gesell., Bd. liii, Heft 1 (1901)Google Scholar.

page 153 note 3 Burmeister, Hermann: “Die Organisation der Trilobiten,” etc., 1843Google Scholar.

page 154 note 1 Op. cit.

page 154 note 2 Billings, E., “Notes on some Specimens of Lower Silurian Trilobites”: Quart. Journ. Geol. Soc., vol. xxvi (1870)Google Scholar.

page 154 note 3 Mickleborough, J., “Locomotory Appendages of Trilobites”: Journ. Cinti. Soc. Nat. Hist., vol. vi, No. 3 (1883)Google Scholar.

page 154 note 4 Woodward, Henry, “Note on the Palpus and other Appendages of Asaphus, from the Trenton Limestone, in the British Museum”: Quart. Journ. Geol. Soc., vol. xxvi (1870)Google Scholar.

page 155 note 1 Jaekel has suggested the name mesotergite to supplant the terms axis or tergum, and pleurotergite in place of pleuron or epimerum, as applied to the trilobites. This seems a useful terminology since the older terms are often loosely used and have somewhat different meanings in other groups. Applying this system of nomenclature to the ventral integument, the writer would propose the terms mesosternite for the membrane beneath each mesotergite, and pleurosternite for the membrane beneath each pleurotergite. The interarticular membranes are not included.

page 156 note 1 Op. cit.

page 156 note 2 Op. cit.

page 157 note 1 Op. cit.

page 158 note 1 Op. cit.

page 159 note 1 Op. cit.

page 159 note 2 Op. cit.

page 159 note 3 Op. cit.