II] GEOGRAPHICAL DISTRIBUTION 27 



different races of similar objects or legends afford an 

 analogous case. As Dr Andrew Lang points out in 

 Custom and Myth, it is held by some students that 

 the use of the bull roarer — to cite a specific instance 

 — by different peoples denotes descent from a common 

 stock, though he considers the more probable ex- 

 planation to be that similar minds, working with 

 simple means towards similar ends, might evolve the 

 bull roarer and its mystic uses anywhere. 



The Cedars of Lebanon afford an interesting ex- 

 ample of discontinuous distribution. They illustrate 

 how a species, which may be assumed to have 

 originated in one region, in the course of its 

 wanderings may undergo slight changes until, at 

 a later stage when the plants have disappeared from 

 parts of the once-continuous area, the remaining 

 outlying groups of individuals are spoken of under 

 different specific names. The cedars of Lebanon, 

 known as Cedrus llbanl, occur as isolated groups 

 on the Lebanon hills as outliers of the larger forests 

 of the Taunus 250 miles distant. The African cedar, 

 Cedrus atlantlca, is separated from the Lebanon 

 cedar by a distance of 1400 miles. Approximately 

 the same distance divides the Lebanon cedar from 

 the deodar, Cedrus deodara, which extends from 

 Afghanistan along the Himalayas almost to the 

 confines of Nepal. Sir Joseph Hooker regards the 

 three cedars as varieties of one species which once 



