QUATEENAEY FAUNA OP GIBEALTAE. 123 



From what he writes, however, it will be seen that that experienced and acute 

 observer fully recognized the similarity between the Pyrenean Ibex with lyrate horns 

 and that which occurs in the south of Spain, and consequently must have regarded 

 C. pyrenaica of Bruch and G. hispanica, Schimp., as synonyms. 



With these preliminary remarks 1 will proceed to make a few observations on the 

 bones of the fossil Ibex, and endeavour to point out its relation to the existing 

 Spanish form. 



Of all the mammalian remains collected by Capt. Brome in the Windmill-Hill caverns 

 and fissures, those of the Ibex are, as I have said, by far the most abundant. They 

 occurred at all depths, and apparently of all periods and of all ages, young and old, 

 associated in the upper chambers of the Genista Cavern with human bones and works 

 of art, and abundantly in the lower passages with the remains of the most ancient 

 forms. 



The specimens, of which cartloads were collected, include almost every part of the 

 skeleton — skulls, horn-cores, vertebrae, limb-bones in profusion, and innumerable iso- 

 lated teeth, of which bushels were met with, together with an immense number of 

 lower and upper jaws &c. 



The bones belong to animals of all ages ; and amongst them are very many jaws with 

 the milk-dentition. Most were more or less thickly incrusted with stalagmite, usually 

 of the red colour; and the substance in the majority of cases was strongly infiltrated 

 with manganese. 



Selected characteristic specimens are represented in Plates XX. and XXII.-XXVI. 



The inspection of these figures, and more especially of those showing the meta- 

 carpals and metatarsals in Plate XXVI., will alone suffice to show that very consider- 

 able diversity of size existed amongst the individuals. In fact, so striking was this 

 diff'erence upon first sight, especially in the mandibles, as to induce us to imagine that 

 they must have belonged to more than one species or subspecies, at any rate. Further 

 investigation, however, has led me to the conclusion that the differences we noticed are 

 due simply to individual variation, or dependent upon sex, and, with regard to the 

 mandibles, to age. 



The mandibles present two very distinct varieties, one much slenderer than the other. 

 But it will be found that the thicker form and greater depth of one of these varieties is 

 simply owing to the circumstance that the teeth are more deeply immersed and, having 

 been in use for a shorter time, descend more deeply into the ramus of the jaw. For the 

 same reason, also, the usually shorter antero-posterior length of the last molar tooth is 

 accounted for. This tooth in the Ibex is more or less contracted in its length towards 

 the summit ; so that the further it is protruded from the alveolus, as it wears down, the 

 longer does it appear to be. But if the tooth in one of the thicker jaws be extracted 

 from the socket, or its root exposed by removal of one side of the alveolus, it will be 

 found to be of the same dimensions as in the other form at the same height. 



