On Protorosaurus speneri (Von Meyer) / by H.G. Seeley.

  • Seeley, H. G. (Harry Govier), 1839-1909.
Date:
1887
Catalogue details

Licence: Public Domain Mark

Credit: On Protorosaurus speneri (Von Meyer) / 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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    the Crocodile, his identification was excusable. Cuvier goes on to argue that the number of teeth in the lower jaw of a Crocodile is at fewest fifteen, while in the upper- jaw there would be seventeen or eighteen extending back to the middle of the orbit, whereas the fossil has only eleven teeth, which reach back to the anterior angle of tire orbit. On this evidence the skull is interpreted as that of a Lacertilian, allied to the Monitor. The author goes on to show that other parts of the skeleton confirm the inference from the skull. Thus the hind limb has five digits, with the number of phalanges in them successively 2, 3, 4, 5, 3, which agrees with the Monitor. The correspondence extends to the larger bones of the extremities. Cuvier only detected two differences of specific value : first, the spinous processes of the dorsal vertebrae are much moi'e elevated than in Monitors ; and secondly, the foreleg is relatively longer in proportion to the femur and the foot. It is unnecessary to offer any detailed discussion of this interpretation, for the figure now given, when compared with Spener’s figure, shows that Cuvier had not the evidence fairly before him. Yon Meyer also studied the published figures, and came to the conclusion that the fossil was neither a Crocodile nor a Monitor; but that it was an extinct type which differed by remarkable modifications and peculiarities from the Saurian group. In consequence he founded the genus Protorosavrus in 1830, and described the species as Protorosavrus Sjicneri in 1832.* Cuvier’s influence, however; continued to govern the views held as to the affinities of this animal, although von Meyer’s name was adopted in Owen’s ‘ Odontography.’ Eventually von Meyer, finding in various museums twenty-one specimens which appeared to him referable to Protorosaurus, made these fossils the subject of an elaborate monograph with nine folio plates, published in 185G. t Nearly all these specimens were studied and measured by the author. But unfortunately the type, which passed into the collec- tion of John Hunter, was unknown to him, and he reproduces in outline Spener’s unsatisfactory figure of 1710. Yet such was von Meyer’s confidence in the figure that he supposes the soft parte about the mouth to be preserved. Nothing of value, therefore, is contributed to knowledge of the skull. The whole of the specimens are referred with some doubt to one species ; and a detailed anatomical description is given of the several regions of the skeleton. The neck is suggestive of the vertebrae of Ornithosaurs and of the Giraffe, but is not compared with that of a Bird because the number of cervical vertebrse recalls that of the Crocodile. The dorsal vertebrae are more numerous than those of the Crocodile, but their shape differs from that seen in all living Saurians [as then known]. The ribs on the whole were Lacertilian. The absence of lumbar vertebrae was regarded as conclusive against affinities with Monitors. The sacral vertebrae in the several examples are considered to number two, three, or four. The tail vertebrae are distinctive in having the neural spine divided. In the shoulder-girdle some resemblances are seen to Archaegosaurus. No important * ‘ Palaeologica,’ 1832, pp. 109, 208. t ‘ Fauna der Yorwelfc,’ “ Saurier aus clem Kupfei-schiefer der Zeclistein-Formation.”