HETEROGONY AND TAXONOMY 205 



(i) If not, then some at least of the difference in 

 relative size (percentage proportions) is prima 

 facie of independent genetic origin, and there- 

 fore of taxonomic significance, 

 (ii) If yes, then prima facie the differences in pro- 

 portions are merely secondary effects of the 

 difference in absolute size, and therefore not 

 of taxonomic significance. 1 



(5) While measurement and simple mathematical analysis 

 will thus give important prima facie evidence, it is of course 

 desirable to apply experimental tests wherever possible to 

 clinch the matter. 



A few examples will illustrate my meaning. 



(1) The Red Deer (Cervus elaphus) of Scotland rarely exceed 

 125 kg. in (clean) body-weight, and rarely show more than 

 twelve points on their antlers. In some localities, the usual 

 run of body- weight is only 75-90 kg., with six to eight points. 

 In some districts of Europe, however (e.g. the Carpathians), stags 

 run to double the maximum Scottish body- weight, with twenty, 

 twenty-five or more points, and there appear to be no con- 

 tinental districts in which the mean weight or point-number 

 is as low as in Scotland. Further, the relative size (weight) 

 of the antlers is clearly much higher in the larger continental 

 stags (Huxley, 1931A). 



It would be natural to consider the low size and antler 

 development of the Scottish deer as constituting criteria of 

 a true geographical variety or sub-species, as has also been 

 done with some island races, which are also small in both these 

 respects. 



The problem is complicated, however, by the fact that in 

 the peat-bogs of Scotland are found the skeletons of deer 

 rivalling the biggest existing European specimens in size and 

 point-number ; and that these date back only a few thousand 

 years (Ritchie, 1920) ; Fig. 90. It would seem difficult to 

 imagine that true evolutionary (genetic) change reducing the 

 body-weight by half could have occurred in such a short space 

 of time. It is true that persistent killing for trophies of the 

 biggest stags, with the best heads, would have had a genetic 

 effect, but this could only have been intensively operative for a 

 very few centuries at most ; and in any case the same process 

 should have been at work on the Continent. Ritchie himself 



1 See Champy (1929, p. 239) where the same problem is discussed 

 along somewhat similar lines. 



