Supplemental note on a double-rooted tooth from the Purbeck beds in the British Museum / by H.G. Seeley.

  • Seeley, H. G. (Harry Govier), 1839-1909.
Date:
1893
Catalogue details

Licence: Public Domain Mark

Credit: Supplemental note on a double-rooted tooth from the Purbeck beds in the British Museum / 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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    canine,” and it is subsequently added that the canine is “ a powerful tooth implanted by two stout fangs.” The tooth as figured (Journ. Acad, Nat. Sci. Philad. 2nd ser. vol. ix, pi. ix. fig. 4) does not bear out the alleged double-rooted character. I have accordingly made an enlarged drawing of this tooth, so as to compare with the tooth of Nuthetes. It is exposed on the inner side ; the crown is enamelled at its summit, with ridges and a slight cinguloid thickening at the base of the enamel ; the extremity of the root of the tooth is lost. I have no doubt it is channelled in the way Professor Osborn’s figure indicates ; but, from the impression left where the anterior angle of the root is lost, which appears to be that of the external surface of the jaw, I cannot regard it as better evidence of a divided root for that particular tooth, than the corresponding impression of a tooth of Nuthetes, already re- ferred to, would give for division of the roots in that specimen. There is a similar pit to that figured by Owen in Nuthetes apparently, on the external side, and a compression of the part of the root beyond it. In any case the evidence is not conclusive that the root was divided in this tooth of Trico- nodon ferooc, which is the only example available for exami- nation in this country. If the fossil gave such evidence, then the roots indicated would be dissimilar in form to those figured in the fossil tooth in the British Museum, No. 48,208. It is possible that a nearer comparison with the crown of that fossil might be found in Plagiaulax medius (Owen), but no one has yet affirmed that the roots of the tooth are divided in that genus. It was from considerations of this kind that I judged, when originally comparing the specimen with the teeth of Purbeck Mammalia, that there was no sufficient ground for discussing the question of it being possibly mam- malian. And now, having figured the evidence for such a comparison, it must be left to future discovery to determine whether the tooth, which has the mammalian character of two roots, can be identified as a Mammal, or whether it must still be regarded as an abnormal form of a tooth of Nuthetes destructor. If the evidence for the double-rooted canine in the Purbeck mammals remains no stronger than I have re- corded, then the weight of evidence is against the suggested mammalian interpretation ; but the resemblance in tlie form of the crown in these two types of teeth is sufficient to make further evidence desirable of the root character in those mam- mals, before the tooth which has hitherto passed unchallenged as Nuthetes is accepted unreservedly as a reptile-tooth which has abnormally developed a divided root.