Observations on belemnites, and other fossil remains of Cephalopoda, discovered by Mr. Reginald Neville Mantell, C.E. in the Oxford clay near Trowbridge, in Wiltshire / by Gideon Algernon Mantell.

  • Mantell, Gideon Algernon, 1790-1852.
Date:
1848
Catalogue details

Licence: Public Domain Mark

Credit: Observations on belemnites, and other fossil remains of Cephalopoda, discovered by Mr. Reginald Neville Mantell, C.E. in the Oxford clay near Trowbridge, in Wiltshire / by Gideon Algernon Mantell. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    PLATE XV. Fig. I. The guard or osselet of a Belemnite (B. attenuatus) invested by the perios- tricum, or external shelly capsule, c', c', c'. a. Part of the chambered phragmocone seen in the alveolus. Fig. II. Another example of B. attenuatus, on which a large portion of the capsule remains, c', c'. Fig. III. Exhibits the most considerable part of the structure of the Belemnite hitherto discovered. The original is twenty-two inches in length. a, a. Remains of the basal portion of the shelly phragmocone; the apical chambered extremity is concealed by the investing capsule and guard, c, c. b, b. Two shelly processes proceeding from the margin of the peristome. c, c', c. The capsule partially investing the guard (at c'), and extending up- wards conceals at c, c, c, the siphonated part of the phragmocone, and expands into the horny receptacle (c), within which the peristomal processes (b, b') are contained. A layer of dark brown animal matter extends from within the outline of the capsule at c, under the processes of the peristome ; and is probably the remains of the soft parts that occupied the interval between the receptacle and the phragmocone. The band on the left of the process b, presents a fibrous structure (d, d), and is marked with oblique lines, as if it were part of the muscular tunic or mantle. Fig. IV. The alveolar part of the guard of a Belemnite split open longitudinally to show the apical chambered portion of the phragmocone (a), with the shell perfect, and imbedded in the alveolus. The phragmocone terminates in a very fine point, and is unsynnnetrical; inclining considerably to one side, in consequence of the position of the axis of the guard (c). A comparison of this figure with figs. 2, 3, 5, Plate XIII., will at once enable the observer to perceive how essentially the phragmocone of the Belemnite differs from that of the Belemnoteuthis. b. The radiated fractured surface of the spathose substance of the guard. Fig. V. The same fossil, with the phragmocone partially divested of the outer shell, to display the edges of the transverse septa. I have never seen in the Oxford Clay, the apical part of the phragmocone of a Belemnite detached from the alveolus. 2 b 2