DERIVATION OF THE FLORA OF HAWAII 31 



"In discussing the hydroids, Professor C. C. Hurtling says : 'A study 

 of the geographical distribution of the forms reveals unmistakable rela- 

 tionship with the Australian region. One indication pointing strongly to 

 this conclusion is the great number of Plumularidae, which constitute 

 about one-third of the species. The west coast of North America, and 

 particularly Alaska, is characterized by a relatively poor representation 

 of that interesting family, while Australia is one of the great centers of 

 distribution of the typically tropical hydroids, the only region that rivals 

 it being our own West Indian waters.' 34 



"Of the brachyurous and macrurous decapods Miss Mary J. Rath- 

 bun says: 'The Hawaiian fauna is almost entirely Indo-Pacific, the 

 islands forming the northeastern, as the Indian Ocean is the southwest- 

 ern limit, for the majority of the species. This is true of the shore and 

 shallow-water forms and in a lesser degree of the abyssal forms, of which 

 many are cosmopolitan. Very little affinity to the fauna of the American 

 continent is shown.' 35 



"In regard to the shallow-water and shore species of starfishes and 

 holothurians (or sea-cucumbers), which I have personally studied, the 

 following general statement seems to apply : The starfishes are all trop- 

 ical forms, and those which are not peculiar to the islands are chiefly 

 Indo-Pacific, and comprise mostly wide-ranging species, some of which 

 extend from the Red Sea to China and Japan, and thence to Australia. 

 Considering the shallow-water species and those from moderate depths, 

 which are peculiar to the Hawaiian group, we find their nearest relatives 

 in the Indian Ocean, East Indies, and north of Australia. In a few cases 

 the same species, from moderate depths, ranges into the East Indies, or 

 as far as the Indian Ocean. Only one undoubted American starfish is 

 found in Hawaii. There is no similarity in the faunas of the west coast 

 of America and of the Hawaiian Islands. 



"The same general facts are true of the holothurians. The shore 

 and reef forms are unmistakably tropical, and the majority are common 

 to the East Indies, Polynesia, Micronesia, Melanesia, and less than half 

 to Australia." 



It is evident that the fauna of the shallower shore waters is closely 

 related to those of the Southern Pacific and Indian Oceans, and not with 

 the much nearer American coast. As to the facilities for transportation 

 possessed by these forms, the writer is unable to speak, but it is remark- 

 able, if they have reached the islands by drifting, that this should never 

 have been from the American coast, but always from the much more 

 remote regions of Australia and the Indian Ocean. 



34 Bull. U. S. Fish Comm., 23, 934, Part III. 1906. 

 85 Ibid., p. 830. 



