DO INSTITUTIONS OK ORGANS REAPPEAR? 223 



This reappearance is the result of artificial 

 selection. The typical Pelargoniums have a bi- 

 lateral symmetry, but horticulturists set a higher 

 value on flowers with radial symmetry, and in 

 consequence have produced flowers with such a 

 symmetry. As a matter of fact, they have paid 

 attention only to the symmetry of the petals, but 

 in modifying that, they have also modified the 

 symmetry of the stamens. 1 



The Privets (Ligustriwri), like most of the Oleacese, 

 possess only two stamens. Nevertheless, it is not 

 uncommon to find among normal flowers of the 

 common Privet specimens with three or four 

 stamens. In this case, however, it is uncertain 

 whether there is a real reappearance of lost organs, 

 or if the loss has not actually become complete. 



Animals. In the case of animals, teratology and 

 embryology furnish a few exceptional cases of an 

 apparent reversion of degenerative evolution. 



As an abnormality in the horse, the first, second, 

 fourth, and fifth digits may reappear. 



Adult man has lost the complete covering of 

 downy hair. According to Ecker, however, hyper- 

 trichosis is an abnormality really due to the re- 

 appearance of this ancestral condition, as may be 

 seen from the mode of its distribution in whorls. 

 Hypertrichosis is a trait frequently inherited, and 

 in this connection the Mauchamp variety of Merino 



1 The flowers upon which these observations were made were 

 kindly provided by H. Cannell of Swanley. 



