Proceedings of 

 the United States 

 National Museum 



SMITHSONIAN INSTITUTION • WASHINGTON, D.C. 



Volume 118 1966 Number 3536 



DECAPOD CRUSTACEANS FROM 

 ST. HELENA ISLAND, SOUTH ATLANTIC 



I 



By Fenner a. Chace, Jr. 



Senior Scientist, Department of Invertebrate Zoology 



Introduction 



As the site of Napoleon's last imprisonment and death, St. Helena 

 is one of the best known solitary islands in the world, but much of 

 its marme fauna has not been accorded the attention that it deserves. 

 The island is an isolated volcanic peak 103^ miles long and 63^ mUes 

 wide, situated slightly east of the mid-Atlantic Ridge at latitude 

 15°58' S. and longitude 5°43' W. The nearest point of exposed land 

 is Ascension Island, about 800 miles to the northwest; southern 

 Angola, roughly 1,200 miles to the east, is the closest point on the 

 coast of West Africa, and Recife, BrazU, approximately 2,000 miles 

 to the west-northwest, is the nearest South American shore. That 

 St. Helena is reasonably old and has long been isolated is suggested 

 by its numerous endemic fishes (Cunningham, 1910, and Cadenat 

 and Marchal, 1963), mollusks (E. A. Smith, 1890), and echinoderms 

 (Mortensen, 1933). 



Although considerable marine collecting has been done at St. 

 Helena by Melliss, Cunningham, Mortensen, Colman, and the Reine- 



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