1885.] DK. H. GVUOW ON THK SPECIKS OF KHEA. 315 



Since we w.iiit to know the proportion of the neck, we must leave 

 the limbs unaltered, but shall have to increase the index for the neck 

 oi llh. darwini in order to render the proportions of the equation 

 correct. This would be the case if the neck of Rh. darwiai were 

 about 57"3 centim. long instead of 52-7. Consequently the neck 

 of Rh. macrorhi/ncha is proportionately longer than that of Rh. 

 darwini. 



Again, the corresponding figures for Rh. americann and Rh. 

 macrorhi/ncha are 4151 and 4191, sufficiently agreeing (considering 

 errors of measurement) to show that the proportionate length of the 

 necks of these two species is the same. Rh. americana compensates 

 the shortness of its neck, caused by the smaller number of neck- 

 vertebrae, by the shortness of its hind limbs. 



As we come to the conclusion that Rh. americana has the shortest 

 hind limbs (p. 310) we can look upon these calculations as checking 

 each other's correctness. Whether compensation be effected also by a 

 greater length of the single cervical vertebrae, it would be very 

 difficult to find out. 



Lastly the corresponding figures for Rh. americana and Rh. darwini 

 are 5033 and 4G06, again showing that we should have to increase 

 the index for the neck of Rh. darwini to about 57"o in order to get 

 a correct equation. This proves beyond doubt that Rh. darwini 

 has the proportionately shortest neck of the three species, and the 

 more so because it possesses the largest hind limbs. 



The length of the neck, expressed in per cent, of the whole vertebral 

 column from the axis to the acetabular vertebra, is Rh. darwini 

 59, Rh. macrorhyncha (il'SS, and Rh. americana 61 '95. 



It was interesting to find out whether there existed a correlation 

 between the limbs and the neck and trunk. The following measure- 

 ments show, first, that Rh. americana and Rh. macrorhyncha agree 

 almost absolutely with each other in the proportions of their limbs to 

 the acetabular-atlas distance ; secondly, that there exists a correlation 

 between the distances applied, unless we attribute to mere coincidence 

 the fact that the same results are arrived at by different calculations. 



H. darwini. H. macrorhyncha. E. americana. 



centim. centim. centim. 

 Length of femur -|- tibia + 



metatarsus 88-3 73- 1 87*4 



Length from atlas to aceta- 

 bulum 88-7 770 920 



73-1 X 92=6725-2 



87-4 X 77 = 6729-8 



