124 ME. G. BUSK OX THE AJs'CIENT OE 



The mere differences in size of the other bones, as exemplified in the metacarpals 

 and metatarsals, shown in Plate XXVI., is also sufficiently explained by individual 

 variation. The general form of the articular surfaces will be seen to correspond ; and 

 although the perimetral index shows considerable differences, this is not more than 

 can probably be accounted for by age and sex. 



On the whole, therefore, there appears to be no reason to consider that more than 

 one species of Ibex is represented in the Gibraltar remains. 



1. Skull. — Several more or less perfect skulls have afforded material for comparison 

 of this important part of the skeleton. 



The one figured in Plate XXII. fig. 1, exhibits the entire upper surface of the cranium, 

 including the bases of the horn-cores in front and the entire occipital condyles behind. 

 Unfortunately, neither in this nor in any of the other specimens are there any remains 

 of the facial bones, except of the upper and lower jaws. 



A second skull, in a veiy fragile condition, but still very perfect when repaired, is 

 equally if not more complete, inasmuch as it preserves a considerable portion of the 

 base. It shows half of the right horn-core divided vertically and transversely, and the 

 right auditory foramen, a small part of the right orbit, with the whole of the temporo- 

 parietal region on the same side. From the state of the sutures the skulls must have 

 belonged to mature animals, which, from the inconsiderable size of the bases of the 

 horn-cores, were most probably females. 



A third specimen shows the left frontal with a part of the orbit, and an entire horn- 

 core (fig. 7) of inconsiderable size, and therefore also probably female. 



A fourth specimen gives a very complete view of the frontal region, with a portion of 

 the left horn-core still attached. 



Besides these are numerous fi'agmentary portions of the cranium, all obviously of 

 the same character. 



Numerous detached horn-cores, besides those already enumerated, have been noticed, 

 all, with the exception of that figured in fig. 7, PI. XXII. , of the same general form 

 and character; and from their size, and comparison with those of the existing Spanish 

 and Alpine Ibex, I should conclude that they have all belonged to females. 



The exceptional form shown in fig. 7 is peculiar by its rapid acumination towards 

 the summit ; but this would appear to be due to some accidental interruption to its 

 development. 



The wide cavernous structure of the interior of the horn-cores, and the peculiar 

 radiate arrangement of the cancelli which is seen in numerous instances, are shown in 

 fig. 2, PI. XXII. 



2. Trunk. — Bones belonging to the trunk are extremely rare in the collection, none 

 liaving been met with, except of the pelvis, beyond a few more or less entire vertebrae. 



One of the most characteristic of these is an almost perfect axis (figs. 4-6, PI. XX.), 

 distinguished from the corresponding bone in Cervus barbarus (fig. 3) by its shortness. 



