. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology; Zoology. PRENTISS: POLYDACTYLISM IN MAN AND DOMESTIC ANIMALS. 271 On examining the other skeletal elements of the manus, in order to determine whether they show reversive modifications, one is at once struck by the form of the trapezoid (Fig. /iT, trzd.). Although of normal size, there is a remarkable change at its distal end; instead of projecting as a wedge between metacarpals ii and in (see normal manus, Fig. F, trzd,, p. 264), and presenting two distal facets nearly equal in size, ntn. OS mag. r 2ns. - un. Fig. K.
. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology; Zoology. PRENTISS: POLYDACTYLISM IN MAN AND DOMESTIC ANIMALS. 271 On examining the other skeletal elements of the manus, in order to determine whether they show reversive modifications, one is at once struck by the form of the trapezoid (Fig. /iT, trzd.). Although of normal size, there is a remarkable change at its distal end; instead of projecting as a wedge between metacarpals ii and in (see normal manus, Fig. F, trzd,, p. 264), and presenting two distal facets nearly equal in size, ntn. OS mag. r 2ns. - un. Fig. K. — Anterior view of left polydactyle manus of the pig, showing carpals and metacarpals, i-v, first to fifth metacarpals; cun., cuneiform; lun., lunar; os mag., os magnum; pis.^ pisiform; scph., scaphoid; trz., trapezium; trzd., trapezoid; un., unciform. 5 natural size. there is only one articular surface, which is slightly convex and occu- pied entirely by metacarpal ii. The trapezoid barely touches metacarpal III; its form and relations to the other skeletal parts thus approach those of the trapezoid of fossil swine (Fig. G, p. 265). In correspondence with these carpal variations, the metacarpals show some changes. The metacarpal of digit ii is slightly larger than nor-. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Harvard University. Museum of Comparative Zoology. Cambridge, Mass. : The Museum
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