igoiH Amazing Faunal Variety 



decurved one as delicate as that of a humming bird. 

 There are also half-beaks with only the upper mandi- 

 ble lengthened — as well as various intermediate 

 forms, each adapted to the peculiar feeding habits 

 of the individual. Each island, moreover, has its 

 own particular species of every type; and a single Perjorce 

 plain, short-billed, olive-yellow bird found in Kauai, '^"^^^" 

 the oldest island, is seemingly the parent stock of the 

 whole assemblage, having been itself derived in turn 

 from some form blown across from the Panama 

 region. 



To the bird lover it is a matter of great regret that 

 several brilliantly colored scarlet or yellow species 

 have been nearly or quite exterminated through the 

 use of their feathers in the making of costly robes and 

 other decorations by the natives. For the magnifi- 

 cent royal cloak preserved in the Bishop Museum 

 thousands of the little creatures must have been 

 sacrificed. 



The land snails of the islands constitute also a BewUder- 

 remarkable array. Those of Oahu have been studied '"f 

 by the Rev. John T. Gulick, a very able naturalist, 

 according to whom they have split up into about 

 175 species represented by 700 to 800 varieties, 

 each wooded tract supporting its own forms. He 

 further notices that a genus is often represented in 

 several valleys by successively allied species in ac- 

 cordance with Jordan's Law.^ In every case, adja- 

 cent valleys furnish the most nearly allied forms, and 

 a full set of the varieties of each species presents a 

 perfect gradation between extremes of type. 



To recognize isolation as a practically essential 

 condition in the separation of species is not neces- 



1 See Vol. I, Chapter xiv, page 329. 



