PART IV 



SYSTEMATIC DISCUSSION 



ECHINODERMATA 



The Echinoderm collection obtained by the "Alva" World 

 Cruise of 1931-32, herein reported, comprises the second part of 

 this report, including the Crinoidea, Ophiuroidea and Holothur- 

 oidea, the Asteroidea and Echinoidea having been reported in 

 Part II, Volume VI, Bulletin of the Vanderbilt Marine Museum. 



Some of the Echinoderms obtained by the "Ara" World Cruise 

 of 1928-29 are also included in the present report. These include 

 Crinoidea, Asteroidea, Ophiuroidea, Echinoidea and Holothu- 

 roidea. 



The "Alva" explorations in Floridian waters, in 1933 and 1935, 

 are here represented by valuable hauls containing Cidaris abyssi- 

 cola (A. Agassiz) . 



One Echinoid obtained by the "Alva" South American Cruise 

 of 1935 is also included in the present report. This is an excep- 

 tionally fine series of the rare Brisaster moseleyi (A. Agassiz) , 

 from Chile. 



With the exception of these Floridian deep water and Chilean 

 sea urchins, the sea-tars, sea-lilies, serpent-stars, sea urchins 

 and sea-cucumbers secured by the "Ara" and "Alva" are all, 

 except one pelagic holothurian larva, representatives of the lit- 

 toral fauna of the Indo-Pacific region, where the unrivalled beauty 

 of their exquisitely coloured, fragile bodies glides with indescrib- 

 able gracefulness, like shadowy silhouettes from an enchanted 

 sea, in the tropic waters of the tidal zone and coral reefs of the 

 Indo-Pacific archipelagoes of the Society Islands, Hawaiian 

 Islands, Fiji Islands, Samoan group, Anambas Islands, Philip- 

 pines, Cochin China Coast, the Dutch East Indies, and the Palm 

 Islands, Queensland. 



Asteroidea 



Only two species of the sea-stars obtained by the "Ara" World 

 Cruise are included in the present report. One of these is the 

 lovely cobalt blue Linckia laevigata (Linne) herein recorded from 

 the Hawaiian Islands, this species having been also obtained by 



