PALMS AND SOLES. 



HARRIS HAWTHORNE WILDER, Ph. D. 

 From the Zoological Laboratory of Smith College. 



With 31 Text Figures. 

 INTRODUCTION. 



Through various recent papers by Gallon, Klaatsch, Hephurn, myself 

 and others the epidermic surface of the human palms and soles has 

 been subjected to renewed investigation and comparisons have been 

 made with the condition found in other mammals, resulting in the 

 establishment of an interesting morphological history, the main points 

 of which may be stated as follows : 



L Pentadactylous quadrupedal mammals normally possess upon the 

 volar surface of each paw ten raised pads or callosities which come in 

 contact with the ground when walking and thus bear the weight of the 

 body. Of these five belong to the terminal joints of the digits, while 

 the remaining five belong to the palmar (or plantar) surface, and are 

 distributed and designated as follows: 



One Tlienar, upon the thenar region at base of pollex. 



One Hypotlienar, upon the like named region along outer border. 



Three Palmar (or Plantar), placed in a transverse row at base of 

 digits, and corresponding to the intervals between digits 2-5. 



II. This typical plan shows various modifications as, for example, 

 the condition in the Felidce, in which the three palmar (and plantar) 

 pads fuse at an early embryonic stage into the single pad so conspicuous 

 a characteristic upon the feet of that group. 



III. In the lower Primates (e. g., Inmius) these pads have suffered 

 much reduction in elevation and have lost their definite boundaries, but 

 the areas corresponding to them are conspicuously marked by curious 

 spiral or looped patterns seen in the papillary ridges of the epidermis, 

 characteristic of this order, the cores or centres of these patterns 

 corresponding to the centres of the lost pads. An extra 6th centre, 



i]My paper unfortunately covered much the same ground as one published by Hep- 

 "burn a few months previous, and the conclusions reached, in so far as the two papers 

 overlapped, were nearly identical. (See Article by Hepburn, Anat. Anz., Bd. XIII, 



No. 16.) 

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