QUATEENAET FAUNA OY GIBEALTAE. 99 



of importance, were it not explained by the circumstance that the lower end of the 

 Ilford radius is diseased, presenting numerous large vascular openings and a general 

 spongy condition, evidently due to what in surgical pathology would be termed chronic 

 osteitis. This diseased condition is strongly manifested also in the radio-ulnar arti- 

 cular surface; and it is a curious circumstance that Sir Antonio Brady's collection of 

 rhiuocerine remains from the Ilford brickfields contains a ri^ht and a left tibia in 

 precisely the same mineral condition, and coi'responding in proportional size with the 

 radius, one of which tibise is very extensively diseased at the distal end, exhibiting the 

 consequences of chronic osteitis in a very advanced stage, being much enlarged and 

 extremely spongy, whilst its fellow presents a similar disease at a less advanced degree. 

 But even in this bone the affection has advanced further than in the radius. It may 

 therefore be fairly concluded that all these bones in the Ilford collection belonged to 

 one and the same individual, and therefore that the enlarged condition of the distal 

 extremity of the radius is abnormal. The shaft of the Gibraltar radius, besides its 

 being a little slenderer than that of the other, is rather more curved in front, and the 

 groove for the extensor tendons at the lower end is deeper and more pronounced than 

 in the Ilford specimen. It is, however, well shown in the latter ; and its depth is 

 apparently diminished merely in consequence of the diseased condition of that end of 

 the bone. 



Now, as this extensor groo^'e appears to be one of the most distinctive characteristics 

 of the radius of B. hemitcechus, as compared with that of any other species, recent or 

 fossil, -with which I have had an opportunity of contrasting it, its existence and depth 

 in the Gibraltar specimen appear to aiford strong evidence in favour of that specimen 

 belonging to the same species. On the dorsal aspect of the two bones I am unable to 

 perceive any difference worthy of note, beyond the fact that all the muscular impressions 

 are more strongly marked in the Ilford specimen. But this is a question of age or 

 development ; and in all other respects the bones appear to be identical. 



The OS limare (PI. XV. figs. 4-S) is absolutely perfect. In mineral condition it is 

 extremely dense and heavy, and highly infiltrated with mauganesic oxide. The only 

 fossil bones with which I have been able to compare it are a right and left from Grays, 

 Nos. 220.38 and 22038 b, in the British Museum, and belonging in all probability to 

 the same individual. These bones are considerably larger than the Gibraltar specimen, 

 measuring: — 



Grays. Gibraltar, 



in. in. 



Length 2-95 2-6 



Width 2-35 1-9 



Antero-posterior diameter 2'3 2T 



The scaphoid facet [a, fig. 4) in the Gibraltar bone is 1"'8 long, and in that from 

 Grays 2"T2 ; and the facet (a, fig. G), which is triangular in the Gibraltar, is circular 



