Decembke 13, 1895.] 



SCIENCE. 



813 



not be allowed to disappear from nomenclature.* 

 Fortunately very few systematic zoologists thus 

 ■disregard the law of priority. 



The last and most general part (pages 9 to 32) 

 Ijegius with a detailed enumeration of the 

 ■changes that take place in the body dviring the 

 evolution of the apes from ancestors with bodies 

 in the normal, horizontal position, and in which 

 progression took place by ordinary running and 

 jumping. Mr. Winge's account of the develop- 

 ment of the limbs is substantially as follows : 

 The Primates were originally raised above the 

 level of the Insectivora through special improve- 

 ment in climbing. Even in the most arboreal 

 of the Insectivora (the Cladobatidm) progression 

 is rather by running and jumping among the 

 branches than by true climbing. The apes, 

 however, climb very differently. The hands 

 and feet seize and hold fast to the branches, 

 and the limbs, especially the ai'ms, lift the body 

 and draw it forward. The fingers and toes 

 clutch the branches and in this way take upon 

 themselves the woi'k formerly done by the 

 claws. Since the claws serve no longer as 

 hooks for clinging, they degenerate and become 

 more like nails fitting the shape of the terminal 

 phalanges which on their part are squeezed flat 

 by the pressure of the fingers and toes upon 

 the branches. To improve the grasping power 

 of the hand and foot, the thumb and great toe 

 stand out from the other digits and become op- 

 posable to them. At the same time the thumb 

 and great toe increase in size and strength, 

 while the positions of their articulations, as 

 well as the form of the bones to which they are 

 attached, are necessarily altered. As a result 

 of efforts to accomplish a variety of movements 

 in all directions, the limbs become more inde- 

 pendent. The thigh and upper arm are held 

 less closely to the sides and are no longer bound 

 by a covering of the body skin. As the limbs 

 become more free the muscles which work them 



* ' ' Proxniliecus kan ikke oprethoMes som egen Slisegt ; 

 ■den falder sammen med Eriodcs. Strengt taget skulde 

 Arten fra Lagoa Santa derefter kaldes Eriodes hrasi- 

 liensis, et Navn, der dog vilde vasre for intetsigende; 

 ■ogsaa Slaigtens andre Former kjendes fra Brasilien. 

 Det er foretrukket at give Arten et ' nyt ' Navn, 

 Eriodes propitheciis ; Ordet PropHhecus fortjener ikke 

 a,t forsvinde. " No. 2, p. 24. 



undergo modifications. In the arms the su- 

 praspinatus, infraspinatus and subscapularis in- 

 crease in strength and produce great changes 

 in the form of the shoulder blade. The del- 

 toideus shows its increased power by causing 

 the clavicle to grow heavier. Of the muscles 

 which work the legs the gluisei and iliacus inter- 

 nus produce the most noticeable changes in the 

 bones to which they are attached. Since the 

 fore limbs are little used as supports for the 

 body, the shoulder blades lose the nearly per- 

 pendicular position which they occupy as a 

 mechanical necessity in most terrestrial mam- 

 mals. To permit freer motion of the limbs the 

 joints either retain the structure characteristic 

 of the Insectivora or become even more loose, 

 especially in the arm, hand, fingers and 

 toes. At the same time the radius and 

 ulna become mutually more free, while the 

 latter loses its connection with the wrist. 

 The metacarpals degenerate somewhat, be- 

 coming at length small and flat, their articula- 

 tions with the proximal phalanges taking on a 

 form which approaches the ball and socket joint. 

 The two small sesamoid bones under each meta- 

 carpal degenerate, and the ridges on the latter 

 on each side of which the sesamoids play dis- 

 appear. The more varied the motions of a 

 limb, the less strength exerted in each move- 

 ment. The muscles of the limb become, there- 

 fore, more evenly developed, none of them in- 

 crease at the expense of the others, and the 

 bones do not give off strongly projecting ridges. 

 Two of the movements which in most animals 

 are performed oftenest and with most strength, 

 the simple flexion of the elbow and ankle, are 

 now less frequent. Hence the triceps and gas- 

 trocnemius have less influence over the other 

 muscles, while the processus anconeus and the 

 calcaneum have a tendency to become weaker. 

 In the primates, [entirely contrary to what occurs 

 in ordinary running and springing animals, the 

 arms become of more importance than the legs, 

 because in true climbing the former are used 

 most. The lengthening arms force the body to 

 take on a more and more upright position during 

 progression, so that when the arms have become 

 very long, walking on all four feet is so difficult 

 that it is entirely abandoned, and the body is at 

 length held in equilibrium over the hind limbs. 



