Page:Popular Science Monthly Volume 62.djvu/50

From Wikisource
Jump to navigation Jump to search
This page has been validated.

in successive stages of these the lateral pads appear at first distinct, then attached to the middle ones as a pair of lateral wings, and finally become completely fused. In the adult cushion the part furnished by each element is still traceable in the irregular contour of the resultant

PSM V62 D050 Arrangement of pads on a mammalian foot.png

Fig. 2. Arrangement of Pads on Mammalian Foot, (a) Typical arrangement; diagram. (b) Typical arrangement; forefoot of rat embryo, (c) Forefoot of mink, showing a slight modification of the type, (d) Forefoot of cat, showing fusion of palmar pads. Abbreviations: A, apical pads; P1-P3, palmar pads; Th, thenar pad; H, hypothenar pad; h. p, hair papilla; I-V, the digits.

mass. The noticeable projecting spur near the wrist is a modified hypothenar pad, but the small bristle-bearing papilla still farther up has nothing to do with it and is not a pad.