ECHINODERMS FROM THE ISLANDS OF NIUAFOOU 

 AND NUKUALOFA, TONGA ARCHIPELAGO, WITH THE 

 DESCRIPTION OF A NEW GENUS AND TWO NEW 

 SPECIES 



By Austin H. Clark 

 Curator, Division of Echdnoderms, United States National Museum 



While attached to the United States Naval Eclipse Expedition to 

 the island of Niuafooii, 1930, Lieut. Henry C. Kellers (M. C), 

 United States Navy, made an extensive collection of the local 

 echinoderms. 



Niuafooii, or Tin Can Island, is one of the islands in the Tonga 

 Archipelago, and is situated between Samoa and Fiji in latitude 

 15° 33' 52'' S., longitude 175° 37' 46" W. It is a volcanic island 

 subject to more or less frequent eruptions, the last of which took 

 place on July 25, 1929. 



Lieutenant Kellers tells me that, except for a distance of about 

 3% miles, Niuafoou is practically surrounded by lava benches backed 

 by basaltic cliffs from 70 to 100 feet in height. These benches are 

 now covered as a result of the eruption of 1929, although in places 

 one can see outcroppings of the old lava. They extend from 100 to 

 200 yards into the sea. On the outer edge they have an almost 

 precipitous drop to the 20-fathom line, which runs out for practically 

 a mile, where the sea floor sinks to the abysses. 



Some of the benches are awash all the time and are mostly entirely 

 covered at high tide. At low water tide pools of all sizes are found, 

 and in these tide pools most of the collecting was done. 



Lieutenant Kellers's collection includes a few specimens that were 

 brought to him by natives from Nukualofa, the seat of government 

 of the Tonga Group, a couple of hundred miles to the southwest of 

 Niuafoou. 



The echinoderms found at Niuafoou were species that would be 

 expected to occur on an island situated in this general region, with a 

 single remarkable exception. This exception is an entirely new 

 genus of echinoids of the family Echinometridae, represented by two 

 species, which is related to Podophora and also to Heterocentrotus. 



No. 2905.— Proceedings U. S. National Museum. Vol. 80, Art. 6. 



68391—31 1 1 



