410 



THE AMERICAN NATURALIST 



[Vol. LII 



labors of coral polyps. A strange "partnership/' with- 

 out parallel in the annals of natural history. 



The islands of the Hawaiian group may be classified on 

 this basis. The large, high islands of the eastern por- 

 tion of the archipelago are composed almost wholly of 

 lava, with small fringing reefs. The low, small islets that 

 comprise the western extension of the archipelago are 

 made almost wholly of coral, that is, in so far as their ex- 

 posed portions are concerned. The coral formations un- 

 doubtedly rest upon a volcanic substratum. The group- 

 ing may be expressed as follows : 



I. Large mountainous lava islands, forming a compact 

 group at eastern end of archipelago; elevations 

 over 1,000 ft. 



A. With well-developed fringing reef : 

 Niihau, 1,300 ft. ; Kauai, 5,250 ft. 

 Oahu, 4,040 ft. 



Molokai, 4,958 ft.; Lanai, 3,400 ft.; Kahoolawe, 

 1,472 ft. 



B. With scanty fringing reef : 

 Hawaii, 13,825 ft. ; Maui, 10,032 ft. 



II. Small, low islets, scattered along the western axis of 

 the archipelago; elevations below 1,000 ft. 



C. Eroded volcanic blocks, 120-900 ft., with fringing 



coral reef : Nihoa, French Frigates Shoals, Gard- 

 ner I. 



D. Elevated coral islands, 45-55 ft., with fringing 



reef: Laysan, Lisianski. 



E. Typical coral atolls: Pearl-and-Hermes, Midway, 



Ocean. 



D. Beefs with visible surf, but no exposed coral: 

 Maro Reef, Dowsett's Reef. 

 The entire series, named in sequence from east to west, 

 is: Hawaii, Maui, Kahoolawe, Lanai, Molokai, Oahu, 

 Kauai, Niihau, Nihoa, Xecker, French Frigates Shoal, 

 Gardner, Dowsett's Reef, Maro Reef, Laysan, Lisianski, 

 Pearl-and-Hermes, Midway, Ocean. The Wo extremes- 

 Hawaii and Ocean Island— present a contrast of wonder- 



