136 PLEISTOCENE MAMMALIA. 
articulation. In the recent Felidz 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 Feles 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 (PI. XX, fig. 7 @; 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 (Pls. XXI, 
fig. 56; XX, fig. 7 4) 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 ¢), in front of which rises an articular eminence (Pls. XX, fig. 7d; XXI. fig. 5d), 
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. 7/). 
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 Fels spelea and Lion which we have 
examined. 
§ 1. 6. Measurements.—In the following table of measurements we have given the 
extreme variations of size and proportion in Felis spelea 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. 
