TELEGONY AND EEVERSION. 



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direction, to prevent the formation of new types or 

 varieties ; and hence, unlike inbreeding, it may be con- 

 sidered retrogressive in its tendency, and at the same time 

 uncertain in its results. If the intercrossing of varieties 

 in the same area arrests the formation of new species, is 

 non-progressive, if not actually retrogressive, the crossing 

 of distinct species from, it may be, widely separated areas 

 will, a priori, not only arrest progressive development — 

 abruptly put an end to the pi'ogress the respective species 

 were making in various directions, — but actually lead to 

 retrogressive changes, in other words, to reversion. The 

 difference between breeding with almost identical inbred 

 members of the same variety and with representatives 

 (neither of them inbred) of two distinct varieties, may be 

 made more evident by an example from amongst the 

 pigeons. If two inbred fantails which present almost 

 identical characters are mated, the offspring will in all 

 probability agree closely with the parents, they may even 

 show some advance in the direction desired by the fancier 

 — in, say, the characteristic attitude or in the number of 

 feathers in the tail. If, however, one of these fantails is 

 afterwards mated with, say, a blue pouter, the young 

 instead of being intermediate between a fantail and a 

 pouter, may closely resemble the wild rock pigeon — may, in 

 fact, have reverted towards the remote ancestor. This 

 would simply be an exaggerated example of the swamp- 

 ing effects of intercrossing. If, therefore, the result of 

 crossing extreme forms is, under ordinary circumstances, 

 accompanied with retrogressive changes, I fail to see how 

 the difference in the markings of Romulus from those of 

 his sire could be considered as due to abrupt or discon- 

 tinuous variation. 



If in Eomulus we have a new creation — a decidedly 

 new variety rather than an attempt at the restoration of a 

 lost ancestor — it is remarkable that he should so forcibly 

 suggest in many ways the Somali zebra, and still more 

 remarkable that he should in the plan of his markings not 

 only agree with this year's crop of hybrids, but also with 



