422 EIGHTH PACIFIC SCIENCE CONGRESS 



but all are more or less common. The East African holothurian fauna 

 is represented by 32 species of 14 genera. Of the 14 genera, all but 

 one (Fatinapta) occur in Australia. Of the 32 species, 24 occur in 

 Australia. The same genera and most of the species also occur through- 

 out the East Indian region. The natural explanation of the similarity 

 between the East African and Australian holothurian faunas, according 

 to H. L. Clark, is that each is a southern or southwestern extension of 

 the East Indian fauna. All the Australian species concerned are found 

 on the eastern coast, evidently migrants from the East Indies. The holo- 

 thurians of the western coast do not resemble those of East Africa as 

 much as those of the northern and northeastern coasts. The holothu- 

 rians of the northwestern corner of the Indian Ocean comprising the 

 Arabian area, including the Red Sea, the Gulf of Aden, and the Persian 

 Gulf, according to H. L. Clark, have 38 species in a dozen genera, all 

 of which except 1 or 2 of doubtful validity occur in Australia and 

 throughout the East Indies. Around 16 species are endemic to the re- 

 gion which confirms the belief that the Arabian region has been more 

 or less isolated for a long period. 



Ceylon, which is somewhat nearer to northwestern Australia than 

 is Mauritius, has around 51 species in contrast to only 28 from Mauri- 

 tius. As far as species are concerned, only 10 of the species listed from 

 Ceylon are reported as yet from Mauritius, but comparison with Aus- 

 tralia shows 26 species in common. Of the Mauritian holothurians only 

 12 are Australian. In other words, 43 per cent of the Mauritian holo- 

 thurians and practically 50 per cent of those in Ceylon also occur in 

 Australia. 



The East Indian area (Indo-Malay Archipelago) includes the en- 

 tire West and Southwest Pacific with the eastern part of Indian Ocean, 

 and is considered the "hotbed" of echinoderms, if not of all marine life. 

 There are over 200 species of holothurians represented in some 40 or 

 more genera. The genera of the East Indian and Australian holothu- 

 rians are otherwise almost identical, according to the findings of H.L. 

 Clark. The two small apodous genera Anapta and Lahidoplax have 

 not yet been found in Australia, whereas all Australian genera occur 

 in the East Indies except the small apodous genus Trochodota. Ac- 

 cording to H. L. Clark, an examination of the list of species found in 

 the two areas reveals that 83 species of the holothurians found in 

 Australia are endemic. Of the remaining 76 species, 67 are East Indian, 

 the remaining 9 being New Zealand or Pacific species. The Australian 

 holothurians may then be said wtih certainty to be of East Indian origin. 



From the findings of H. L. Clark and others, it has been pointed 

 out that the East Indies is the place of origin of all the tropical Aspi- 



