On the fossil remains of reptiles, and on chelonian foot-tracks, from the Devonian strata of Morayshire / by Lambart Brickenden and Gideon Algernon Mantell.

  • Brickenden, Lambart.
Date:
1852
Catalogue details

Licence: Public Domain Mark

Credit: On the fossil remains of reptiles, and on chelonian foot-tracks, from the Devonian strata of Morayshire / by Lambart Brickenden and 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.

    7/24 (page 101)
    one side, the extremities are partially extended, and the thigh-bones directed forwards ; the tail is curved towards the right. At the first glance the fossil presents so striking a resemblance to the skeleton of a small lizard, that upon a hasty inspection, I had no doubt that it belonged to a lacertian reptile, and anticipated but little difficulty in determining the form and relations of the original: but a careful examination disclosed anatomical characters, which, if I have rightly interpreted, indicate an approach to the batrachian type : the results of a rigid investigation and comparison of every recognizable part of the skeleton are embodied in the following description. Cranium.—From the outline of the mutilated skull, which can be traced but imperfectly, the form of the head appears to have been oblong, with a gently rounded muzzle (PI. IV. 3,4). The remains of the vomerine and palatine bones are seen between the imprints left by the lower jaw, but are too much crushed to afford any satisfactory in- formation as to the original form and structure of this part of the cranium. The impressions of the distal or articular portion of each ramus of the lower jaw are faintly shown, as sketched in PI. IV. 3, and 4, a, a; but I have searched in vain for indications of the divisions of the several parts that enter into the composition of the inferior maxillary bone in reptiles ; even the outline of the anterior portion of the dentary piece is not traceable. Teeth.—Capt. Brickenden informs me that when the fossil was discovered there wTere several extremely minute conical teeth, having a smooth polished surface; they were displaced, but distinctly visi- ble. Under a highly magnifying power two or three teeth are still discernible (PI. IV. 1,1a, 2), but their original position in the jaw is not obvious. I have been unsuccessful in my attempts to make out the structure of the occipital condyle. Vertebrce.—I cannot detect the atlas or axis; the first vertebra seen in PI. IV. 9, is probably the third or fourth cervical: the spinal column from this point to the sacrum consists of twenty-four verte- brae, as in the Iguana, each bone bearing a pair of ribs. Whether the bodies of the vertebrae were concavo-convex, as in the Lacertians, or the reverse, as in the Salamanders*, or doubly concave, as in the living Axolotl (a Batrachian that inhabits the Lakes of Mexico), I cannot positively determine; but the sparry replacements of some of the intervertebral spaces appear to indicate the latter modification of structure: and if these casts exhibit the normal form, the vertebrae must have been deeply concave at both extremities: the length of a dorsal vertebra is one-ninth of an inch. The vertebrae are for the most part exposed dorsally; that is, the upper part of the neural arch is deeply imprinted on the stone, in PI. IV. 8 : and sparry casts of the bodies of the bones constitute a portion of the spine in PI. IV. 9. A cast from the specimen, PI. IV. 8, exhibits the form of the upper part of the vertebral column, so far as it can be determined from the * In the Salamandridce the vertebrae are convex anteriorly and concave poste- riorly : the reverse of those of Frogs and Lizards : in the Axolotl they are deeply cupped at both ends.