DISPERSAL OF LIFE VISHER 315 



often been mentioned in connection with hurricanes. A specific case 

 of interest is mentioned by Dr. F. Woods-Jones ^ concerning insects 

 at Cocos-Keeling Island in the Indian Ocean. During a severe 

 northwesterly wind associated with a hurricane, hundreds of dragon- 

 flies were driven the 700 miles from* Sumatra and Java, the nearest 

 land, to this little island. However, as the island possessed no suit- 

 able environment for dragonflies the introduction was ineffectual 

 in spite of the large numbers driven there. But if a marsh or other 

 favorable environment for these insects should develop on the 

 island, there is no question that within a short time some storm 

 wind would stock it with dragonflies. 



An actual increase of the permanent fauna of Cocos-Keeling 

 Island took place dui-ing Doctor AVood- Jones's residence there, shortly 

 after they had added a new plant, tomatoes grown from seed. At 

 first the tomatoes had no enemies, but before the first crop was 

 ripened an insect pest was brought by the same cyclonic gale that 

 brought the dragon flies from Java and Sumatra. Although Cocos- 

 Keeling Island is in the belt of trades, which blow Avitli exceptional 

 strength and persistence from Australia, almost no Australian species 

 are found in the fauna. Doctor Woods-Jones believes this fact is 

 an illustration of Alfred Russell Wallace's generalization that fly- 

 ing forms are rather well adjusted to the prevailing winds, just as 

 aquatic forms living in a regular current commonly are adjusted 

 to it so as not to be swept away. But the sudden, irregular, violent 

 winds and currents sometimes associated with tropical cyclones take 

 many individuals by surprise and carry them aAvay from land. 



Not only are animals with wings sometimes carried long distances 

 by hurricane winds, but many forms attached to leaves are thus 

 carried. The stripping off of almost all the leaves occasionally ac- 

 complished by hurricanes has been mentioned often. Some of these 

 leaves are carried far, and on these parachutes are sometimes at- 

 tached worms, larva? eggs, or small snails. ^° 



HURRICANE CURRENTS AS DISPERSING AGENCIES 



The strength of the abnormal ocean currents set in motion by 

 liurricane winds is mentioned repeatedly in the Pacific Islands 

 Pilot.^^ The significance of such abnormal currents may be illus- 

 trated by a statement concerning the Hawaiian Islands. A few 

 years ago the mangrove was introduced upon the island of Molokai. 



» Professor at Adelaide University, Australia. Remarks following my paper before the 

 Koyal Society of New South Wales, November, 1921. 



1" nisbry, H. A., " The dispersal and afBnities of Polynesian land snail faunas," Proc. 

 First Pan-Pacific Scientific Conference, vol. 1, p. 149, Honolulu, 1921. 



" U. S. Hydrographic Office, Washington, 1920. 



