Like the rest of the material of Natural Trap, the third metacarpals (MC) were measured by John Howe (sheets I and II) and one student (sheets III and IV). Looking at the diagrams (Fig.1,2) it is obvious that they did not measure the diaphysis depth (4) in the same way. There is no way to increase the measure 4 but there is a way to make in smaller : by measuring it just above the distal articulation, as was proposed by A. von den Driesch (1976). I assume that John Howe used this way. In Table 1 are the original data and in Table 2 - the ones I have decided to use after discarding the diaphysis depth measured by John Howe and suppressing some redundant data.

The scatter diagram of diaphysis width versus maximal length (Fig.3) shows that some MC are different from the rest by their slenderness and/or their size. They are discussed in the main text. The bulk of the material has hemione-like slenderness but the size is larger.

Middle-sized slender MC (A. cf. pseudaltidens)
Statistics and Simpson’s diagrams bone by bone are in Table 3.

Very slender MC
They seem close to the specimen from G Quarry (Fig.4).

A. leoni-like MC
I refer to A. cf. conversidens seven MC (Fig.5). The Bagget Ranch data were published by Quinn (1957).

Undetermined MC
Fig.6.

References

DRIESCH A. von den, 1976. - A guide to the measurement of animal bones from Archaeological sites. Peabody Museum Bulletins, Harvard University (1), 137p., 62 fig.

QUINN J. H., 1957. Pleistocene Equidae of Texas. Bureau of Economic Geology, University of Texas, Report of Investigations 33 : 51pp.