Geology and Mineralogy considered with reference to Natural Theology/Plate 30

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Geology and Mineralogy considered with reference to Natural Theology, plate 30.png

Plate 30. V. I. p. 234.

A large fossil pen of Loligo; from the Lias at Lyme Regis. In the collection of Miss Philpot. (Mrs. Buckland. Original.)
AA. Barbs of the pen, proceeding from the outer edges of the marginal bands.
B.B. Marginal bands dividing the bases of the barbs from the internal part or body of the shaft.
C. Axis of the Pen, dividing the body of the shaft into two equal parts.
D. Transverse section across the Ink bag.
d. First or upper plate. This plate is very thin, and smooth, and its structure is obscure, except on the right marginal band at d', where the longitudinal ridges on its surface are very distinct.
e. Upper surface of second plate, marked with broad wavy lines, passing on each side from the axis outwards, across the body of the shaft, and over the marginal bands.
f. Upper surfaces of a third plate, exhibiting minute curved striæ, ascending symmetrically in opposite directions from each side of the axis of the shaft C, and descending towards its margin. These curved striæ are intersected by minute longitudinal straight lines, running nearly parallel to the axis of the shaft. Towards the apex of the shaft atf, the broad transverse curves predominate over the fine longitudinal fibres which lie beneath them. At g, no transverse curves are visible.[1] (Mrs. Buckland. Original.)

  1. Herman von Meyer (Palæologica, 1832, P. 322.) mentions the occurrence of ink bags, together with the horny internal shells of Sepia, (Onychoteuthis) in the Lias of Culmbach and Banz.