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PROCEEDINGS OF THE NATIONAL MUSEUM 



both the western and eastern Atlantic, only three species are common 

 to St. Helena and eastern America, whereas seven West African species 

 are represented at St. Helena. 



Eastem 

 Pacific 



Western 

 Atlantic 



Eastem 

 Atlantic 



Indo- 



Pacific 



SynalpJoeus jrHzmuellerl 



Grapsus grapsus 



Micropanope melanodactylus 



Brachycdrpus biungukulatus 



Planes cyaneus 



Planes tnarinus 



Dromia erythropus 



PanuUrus echinatus 



Micropanope mjopunctata 



Plagusia depressa 



Calappa gallus 



Enoplojnetopus antUlensis 



Dardanus imperator 



Pachygrapsus loveridgei 



Acanthonyx sanctaehelenae 



Pisa sanctaehelenae 



Pontonia pinnophylax 



Alpheus macrocheles 



Scyllarides herklotsii 



Albunea carahus 



Actaea margaritaria 



Dardanus arrosor 



Alpheus paragracilis 



Figure 15. — Geographic distribution of the decapod crustaceans of St. Helena Island. 



Only one of the decapods, the oceanic crab Planes cyaneus, probably 

 reached St. Helena from South Africa. This ratio corresponds with 

 that in the St. Helena echinoderms, of which only Asterina exigua now 

 occurs in South Africa. Mortensen believed that this sea star was 

 transported on floating kelp, which is regularly carried from South 



