INTRODUCTION 



The Echinoderm collection secured by the "Alva" world cruise, 

 1931, although numerically small, contains representatives of the 

 five major groups of this phylum, of which only the Asteroidea 

 and Echinoidea are included in the present report. The starfishes 

 and sea-urchins obtained are all members of the littoral fauna 

 of the Indo-Pacific region, exquisitely sculptured and magnifi- 

 cently colored sea-stars and urchins whose beauty is but an incon- 

 spicuous mosaic in the glorious coral reefs and tidal zone of the 

 Palm Islands, Queensland, Durian Straits, Bali, New Caledonia, 

 Fiji Archipelago, Marquesas Islands, Samoa, Society Islands, and 

 the volcanic shores of Galapagos. 



The starfishes include four species, three of which are from 

 the Society Islands. The Tahitian series of Culcita novae-guinae 

 Muller and Troschel consists of unusually fine specimens of this 

 remarkable Asteroid. The Acanthaster planet from the Society 

 Islands are also magnificent specimens. The tropicopolitan Linckia 

 guildingii is the third Tahitian species. New distribution records 

 for L. laevigata are also presented. 



The sea-urchins are represented by ten species, for several of 

 which new distribution is reported. The occurrence of typical 

 Eucidaris thouarsii Valentin in Galapagos is verified. The speci- 

 men of P/22/ZZacani/iz«5 mpmah's (Lamarck) from New Caledonia 

 is a remarkably fine one and apparently the first record of its oc- 

 currence here. 



The ten species of Echinoidea are distributed as follows : 



Eucidaris thoiuirsii (Valentin), Galapagos. 



Prionocidaris hacvlosa annulifera (Lamarck) , Seba Seba Bay, 

 Durian Straits. 



Phyllacanthus imperialis (Lamarck), Noumea, New Cale- 

 donia. 



Echinothrix diadema (Linne) , Society Islands. 



Echinothrix calamaris (Pallas), Samoa. 



Temnopleurus toreumaticus (Klein), Durian Straits. 



Tripneustes gratilla (Linne), Marquesas Islands and Society 

 Islands. 



Parasalenia gratiosa ( Agassiz) , Samoa. 



Echinometra mathaei de Blainville, Tahiti, Society Islands. 



Heterocentrotus trigonarius (Lamarck), Tahiti, Society 

 Islands. 



