QUATERNAET FAUNA OP GIBEALTAE. 95 



given will be quite sufficient to show that they are toto coslo distinct ; and the sam e 

 may be said with respect to M. bicornis, and, I may add, to any other of the existing 

 species with which I am acquainted. 



2. Trunk. 



The only bone belonging to this division of the skeleton, beyond a small fragment of a 

 rib, in all probability rhinocerine, is the atlas, represented in PI. XVIII. figs. 1 & 2. 



The remains of this vertebra consist of nearly the entire left and a considerable 

 portion of the right half of the bone. 



When placed in their proper positions the two fragments have evidently formed parts 

 of the same vertebra, which has been broken in the process of exhumation, or extraction 

 from the hard stalagmite deposit in which it was imbedded. The bone is that of a mature 

 animal. In its present condition it measures about 11"'0 in extreme breadth ; and if 

 it had any unossified epiphyses, it might, when entire, have measured perhaps 12"-0. 

 The antero-posterior diameter of the transverse processes is about 4", or a little more ; 

 and the extreme antero-posterior length of the bone, measured between the summits 

 of the anterior and posterior articular processes, is about the same. The dorsal portion 

 of the ritig is absent ; so that the configuration of that part, which would seem to differ 

 a good deal in different species (at any rate it does so in E. unicornis and B. bicornis), 

 cannot be ascertained. The posterior articular surfaces look obliquely inwards, their 

 planes meeting at an angle of about 100° or 110°. The anterior articular cup, when the 

 fragments were fixed in plaster of Paris in their proper position, fitted exactly upon the 

 occipital condyles of a skull of R. hemitoechus in the British Museum. The only 

 existing species with whose atlas I have had an opportunity of comparing the Gibraltar 

 specimen are R. unicornis and R. bicornis, from both of which it differs so widely in 

 many respects, that it appears to me needless to enter into any particular comparison. 



I have not been able to compare the atlas with that of any fossil species ; but Cuvier ' 

 notices and figures a fossil atlas of Rhinoceros, which was found in 1750 near Schartfels 

 (Schwarzfels ^), and first described by HoUman^, which presents many characters in 

 common with it, amongst which are: — (1) the comparatively small size, Hollman's 

 specimen not being more than 13"-7 broad and about 5"-0 in the antero-posterior 

 width of the transverse processes; (2) the incompleteness of the anterior arterial 

 foramina, which in the Gibraltar bone are represented by wide notches; (3) the 

 obliquity of the posterior articular surfaces, whose planes in Hollman's specimen, 

 according to Cuvier, met at an angle of about 90°. 



With respect to the last two particulars, Cuvier remarks that in a recent atlas 

 (probably R. unicornis "l) with which he instituted a comparison the arterial foramina 

 were complete, and the posterior articular surfaces formed a right angle with the longi- 

 tudinal plane of the bone. 



' Oasemens Poseilee, ed. 4, t. iii. p. 143, pi. 46. figs. 0-8. 

 * Comment. Soc. Gotting. 1751, p. 251. 



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