40G 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 (repre- 

 sented in Plate XXXV. 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. 493.55) originally formed a portion of the 

 same bone. The detached head agrees with the femur of VuUur and 

 Gyps, as distinguished from that of Aquila, by the large size of the 

 dejiression for the attachment of the ligamentum teres. It has a 

 diameter of 0,018, against 0,01.5 in V. monachus. The distal ex- 

 tremity 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 attach- 

 ment of a muscle or Hgament. The transverse diameter of the fossil 

 is 0,044 and that of the recent bone 0,037 ; the former being, as in 

 tlie 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 XXXV. fig. 8) as well as the imperfect terminal 

 phalangeal (shown in fig. 9 of the same Plate) resemble the corre- 

 sponding bones of Yultur 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 dis- 

 tinguished 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 

 i'rom these figures that in Gyj^s 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 VuUur 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 of Gijps 

 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 corre- 

 sponding vertebrae of the latter genus. 



The above description will at once show that the imperfect late cervi- 

 cal vertebra from the Maltese deposits (represented in Plate XXXVI. 



