On a new reptile from Welte Vreden (Beaufort West), Eunotosaurus Africanus (Seeley) / by H.G. Seeley.

  • Seeley, H. G. (Harry Govier), 1839-1909.
Date:
1892
Catalogue details

Licence: Public Domain Mark

Credit: On a new reptile from Welte Vreden (Beaufort West), Eunotosaurus Africanus (Seeley) / by H.G. Seeley. 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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    [^From the QrAKXERLY Journal of the Geological yocii»Y/or November 1892, Vol. xlviii.] 0)1 a New Eeptile /rom Welte Vreden (Beaufort West), Eunotosaurus africanus (Seeley), By H. G. Seeley, Esq., F.K.S., F.L.S., F.G.S., Professor of Geograxjhy and Lecturer in Geology in King’s College, London. When I visited Welte Vreden, near Beaufort West, Cape Colony, in August 1889, Mr, L. Pienaar gave me a small ovate concretion which contained the dorsal region of a new reptile. As preserved it is 7‘5 centimetres long and 5‘75 centimetres wide. It shows on the ventral aspect the under surfaces of seven con- secutive dorsal vertebrae. These centrums are more slender and elongated than in any South African fossil previously known. They decrease in length from front to hack. The first (which may be the first dorsal) is fully l'2o centim. long, while the seventh is 0'7o centim. long, and is probably the last dorsal or lumbar vertebra, since the pubis is found immediately behind it. These vertebrae in form and number suggest the Chelonian type. They are of an elongated hour-glass form, and relatively longer than in Teleosaurs. The centrum appears to be hollow, but this condition is probably the effect of deep penetration of the conical notochordal substance, as in Mesosaurus, and the vertebrae referred by Sir K. Owen to Tapino- cephalus. A conical cavity penetrates the posterior end of the sixth centrum, and apparently the anterior end of the first, so that the constriction in the middle length of the centrum is due to the tapering away of these conical cups. The articular faces are not exposed, but are inferred to be approximately circular, and the under surface of the centrum is rounded from side to side. In the seventh vertebra a slight lateral widening is seen in front, towards the neural arch. (See fig. 1, p. 584.) The neural canal is fairly large and rather wider than high, but is only exposed by fracture of the neural arch on the dorsal surface. There is no indication of such transverse expansion of the neural arch as is seen in the Pareiasauria and Mesosauria, so far as can be judged from the bony tissue preserved. The neural spine is com- jnessed as shown in the first vertebra, but there is no evidence of its length. There is no satisfactory evidence that transverse processes were developed : and the ribs were certainly attached closely to the sides of the neural arches, much as in Chelonians, but apparently more widely along the side of the arch. The ribs are remarkably massive. They are long and convexly curved, deep and convex from side to side in the proximal ventral portions, which are only exposed obliquely on the posterior aspect where the ribs are crushed • downward and forward. Above this powerful support there is a thin plate which e.xtends beyond the inflated inferior portion of the rib, so as to give an antero-posterior extent of about I centimetre. Hence the ribs appear to be as wide as the vertebrae are long. This expanded superior layer is broken