Description of the Skull of a Dentigerous Bird ( Odontopteryx toliapicus , Ow.) from the London Clay of Sheppey

Abstract

Amongst the additions to appear in the second edition of my ‘British Fossil Mammals and Birds’ I have anticipated the descriptions of certain species, as in the case of the gigantic Eocene bird, equalling in size the larger New-Zealand Moas. The still more remarkable Ornitholite, also from Sheppey, which I am now about to describe, has stronger claims to be made known, without delay, on account of the transitional character which it manifests to the Pterosaurian order. The fossil consists of a large portion of the skull, which, when the specimen was received in the British Museum, was more or less imbedded in the London Clay; the clearing out of the matrix by the careful and skilful hands of Mr. Davies, Senior Attendant in the “Geological Department,” brought to light the tooth-like processes of the alveolar borders of both upper and lower jaws, to which the uniqueness of this Eocene fossil is due; but the distinctive cranial characters of the warm-blooded feathered vertebrate are unmistakable. The well-developed brain, expanding transversely in its posteriorly placed box (P1. XVI. figs. 1-4, 3,7,11), making the base of a long cranial cone gradually tapering forward, the capacious lateral orbits ( ib. figs. 1, 2, 4, 0, 0), and the single hemispheroid condyle ( ib. fig. 3, 1) are avian: the large and long, freely articulated, dependent tympanic bone ( ib. figs. 1, 2, 3, 28), the slender, straight and styliform zygomatic bar ( ib. figs. 1 & 2, 26) received behind into the articular cup of the tympanic