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Show 406 MR. R. LYDEKKER ON SOME LARGE [May 20, of two other specimens of the tarso-metatarsus, as well as another of the distal extremity of the tibio-tarsus. Of the femur we have a specimen of the distal extremity (represented in Plate X X X V . figs. 4, 4a). This bone belongs to the right side, and it is practically certain that the detached head of a right femur in the Museum (No. 49355) originally formed a portion of the same bone. The detached head agrees with the femur of Vultur and Gyps, as distinguished from that of Aquila, by the large size of the depression for the attachment of the ligamentum teres. It has a diameter of 0,018, against 0,015 in V. monachus. The distal extremity agrees in all respects with the corresponding portion of the femur of the existing species (represented in figs. 5, 5 a of the Plate cited) even down to the position of the fossa (marked d) for the attachment of a muscle or ligament. The transverse diameter of the fossil is 0,044 and that of the recent bone 0,037 ; the former being, as in the case of the metatarsus, about one fifth larger than the latter. The length of the femur of V. monachus being 0,133, the calculated length of that of the fossil species would be 0,159. The imperfect proximal phalangeal of the third digit of the pes (represented in Plate X X X V . fig. 8) as well as the imperfect terminal phalangeal (shown in fig. 9 of the same Plate) resemble the corresponding bones of Vultur monachus, with the same excess in size as holds good with the other portions of the skeleton. So far as I am aware there are no very well-marked characters by which the bones of the hind limb of Vultur can be generically distinguished from those of Gyps. A marked osteological distinction between the two genera is afforded, however, by the cervical vertebrae, more especially those from the hinder part of that region. To exhibit this difference a late cervical vertebra of each genus is figured in the two accompanying drawings (figs. 1, 2, p. 407). It will be seen from these figures that in Gyps the lateral borders of the inferior surface of the centrum are much more emarginate than in Vultur, while the posterior extremity of this surface is more expanded. The same surface of the centrum is also convex and has a sharp descent to the very deep pit immediately behind the anterior articular surface ; whereas in Vultur this surface is almost flat, and nearly in the same plane as the lower border of the anterior articular surface. In consequence of this difference a front view of the cervical of Gyps shows an abrupt vertical surface some distance behind and below the anterior articular face of the centrum, which is totally wanting in that of Vultur. Moreover, the anterior face of the centrum oi Gyps is relatively larger than in Vultur, with much sharper and more oblique lateral borders. Again, in the figured vertebrae of Gyps the inferior surface of the centrum has a median pneumatic foramen totally absent in that of Vultur ; while in the succeeding posterior vertebrae of the former there is a foramen situated below the root of each lower transverse process, which are unrepresented in the corresponding vertebras of the latter genus. The above description will at once show that the im perfect late cervical vertebra from the Maltese deposits (represented in Plate XXXVI. |