﻿136 PLEISTOCENE MAMMALIA. 



articulation. In the recent Felidse also a similar amount of variation may be observed. 

 The articulation for the fifth metacarpal (fig. 4 e) is much less concave than those of the 

 second and third ; the proximal edge is much thickened and flattened, the palmar is 

 small. The form of the third and fourth metacarpals is much stouter than that of 

 the others, and the arch-like curvature is less and the dorsal surface is more 

 flattened. 



The fifth metacarpals of the Carnivora resemble each other so closely that it requires 

 some attention to distinguish between forms of nearly the same size. In the Eeles gene- 

 rally, they have a tendency to be triangular in section, to be more tapering, and to arch 

 more decidedly in a palmar and outward direction than any of the others. The proximal 

 articulation for the unciform (PL XX, fig. 7 a; XXI, fig. 5 a) forms a continuous surface 

 with that of the fourth metacarpal, and like it is convex only in a vertical direction ; it 

 covers the whole of the end of the bone. The inter-metacarpal articulation (Pis. XXI, 

 fig. 5 £; XX, fig. 7 b) is a flattened surface, segmental in form, set at right angles to 

 that for the unciform, and interrupted inferiorly by a large ligamentary notch (PL XX, 

 fig. 7 e), in front of which rises an articular eminence (Pis. XX, fig. 7 d; XXI. fig. 5 d), 

 which fits into a corresponding hollow in the fourth metacarpal. Externally the head 

 presents a large tuberosity (PL XXI, fig. 5 e), which affords attachment to the strong 

 ligaments that bind the bone to the unciform, cuneiform, and pisiform. On the palmar 

 surface also there is a large tuberosity (PL XX, fig. If). 



Nearly all the ridges on the metacarpals are for the attachment of ligaments ; the 

 only direct muscular attachments being those for the very small muscles connected with 

 the flexion of the digits. 



We have not attempted a more detailed description of these bones because of the 

 great variation in the form of their articular surfaces, which renders it almost impossible 

 to lay hold of characteristics common to a large series. The few points of difference that 

 we have given are constant in all those of Felis spelaa and Lion which we have 

 examined. 



§ 1. 8. Measurements. — In the following table of measurements we have given the 

 extreme variations of size and proportion in Felis spelaa as compared with corresponding 

 bones of lion and tiger. The gigantic size of the second metacarpal from Crayford 

 (PL XIX, fig. 6) is visible also in the metatarsal, fig. 7 of the same plate, and in an 

 upper canine which was discovered after our plates were engraved. All these probably 

 belonged to the same individual, and are far larger than any other remains of the animal 

 that have yet been found. 



