TBANSACTIONS OF SECTION H. 909 



At times he has felt so sceptical as to the value of the work he was doing that 

 he has abandoned it for years. With this feelinp strong on him he read Schwein- 

 furth's * Heart of Africa/ and from this admirable repertory of careful observation 

 he drank in new hope and fresh faith. He cannot express too strongly the value 

 he sets on it, or the admiration it has called forth by its profoundly philosophical 

 reflections and manly, honest tone. 



Finally, whatever love of natural history the author has he o\^-es mainly to an 

 early perusal of the ' Voyage of a Naturalist in the Beagle.' 



4. On the Frehensile Power of Infants. By Dr. Louis Robinson. 



5. The Integumentary Grooves on the Palm of the Hand and Sole of the 

 Foot of Man and the Anthropoid Apes. By David Hepiscen, M.B., 

 CM., F.B.8.E., Senior Demonstrator of Anatomy, University of Edin- 

 burgh. 



After a short introductory statement the author drew attention to recent 

 literature dealing with this subject, and then proceeded to summarise and contrast 

 the functions of the hand in man and apes. This was followed by a comparison 

 of the obvious surface characters and differences found in the hands of man and 

 apes. The grouping of the muscles and their modes of action were next dealt 

 with. It was then shown that it was possible for the flexor, adductor, and 

 opposing muscles to leave their imprint on the palm. 



As a result of flexion the skin of the palm and of the digits is thrown into 

 folds separated by grooves, whose direction is always more or less transverse to 

 the long axis of these parts, but the transverse direction may be modified bv 

 special conditions, such as the increased development of certain muscles. The 

 movement of adduction or contraction results in the narrowing of the palm, and 

 this is indicated by grooves v.'hich run in the long axis of the palm ; but since the 

 muscles of this group arise in relation to the middle line of the hand, the grooves 

 radiate more or less distinctly from a point in front of the wrist. 



Similarly the movement of opposition is indicated by oblique lines, but these 

 usiially blend with the radiating lines. 



Following this, the hand of each ape was taken in turn, its principal characters 

 pointed out, the grooves on its palm indicated by reference to casts and drawings, 

 and the variations from the typical arrangement of the grooves accounted for. 

 After the palm of the gibbon, orang-utan, chimpanzee, and gorilla had been treated 

 in this way the hand of man was similarly discussed. 



Here it was shown that the same grooves prevail throughout the series, but 

 that the lines of flexion become modified as the muscles in the ball of the thumb 

 and ball of the little finger increase in size and importance. From being transverse 

 in the gibbon, they gradually become more and more oblique, until, as in man, the 

 outer end of the anterior line is pushed towards the cleft between the index and 

 medius digits, while the inner end of the middle line is smoothed down so that it 

 no longer reaches the inner border of the palm. Again, wiiat is a posterior 

 transverse line in the gibbon is lost in man. 



Of the radiating or longitudinal lines only one is left in man, and that occupies 

 the middle of the palm; but even this may not be constant. The oblique line 

 which in man surrounds the ball of the thumb is partly due to oi)i)osition and 

 partly due to adduction, so that it may also be regarded as one of the radiating 

 series of grooves. Lines to indicate opposition of the little finger are ill-defined 

 even in man, where they may be seen as faint lines running somewhat parallel to 

 the oblique line of the thumb, i.e., outwards and forwards from the inner border of 

 the palm. 



Following the hand, the foot was treated in a similar way. First, a summarv 

 and contrast of its functions in man and apes, then a statement of tlie surface 

 characters and differences in the feet of man and the apes. In the foot there are 



