DISTRIBUTION OF INDO-PACIFIC LITTORAL HOLOTHURIOIDEA 423 



dochirote holothurians that have spread all over the Indian Ocean and 

 the Pacific areas. The over 200 species of holothurians reported from 

 the East Indies with some 40 or more genera proved the above assertion. 

 An area or province where there is the most number of species of ani- 

 mals is usually considered the place of origin of the said animals. 

 Basing it from this hypothesis, we may also conclude that the East 

 Pacific area, particularly the Gulf of California, is the place of origin 

 of the Dendrochirote holothurians. 



The North Pacific and South Pacific provinces, which are not in- 

 cluded under the two main regions but which may be regarded closer 

 to the polar regions, have the least number of holothurian fauna. The 

 writer listed about a dozen species from the North Pacific and almost 

 none from the South Pacific. (See chart). All the species recorded 

 from the North Pacific are dendrochirotes and one single species of an 

 apodous holothurian, whereas the two species from the South Pacific 

 are aspidochirotes. None of these cold-water forms is endemic to the 

 place. The unequal distribution of the North and South Pacific holo- 

 thurian fauna is due to the unequal land masses and the differences in 

 the expanses of the ocean. The North Pacific has great continental 

 masses with almost continuous connections between the various tem- 

 perate and arctic shelf regions, although it runs through climatically 

 different regions. The South Pacific is the opposite of the North, with 

 wide expanses of ocean separating the great shelf regions, and with 

 large tracts of abyssal deep sea. 



Bibliography 



Clark, H. L. 1898. Notes on the Bermuda Echinoderms. Aim. New York 



Acad. Sd. Bd, 11. 

 1899. Further notes on the Bermuda Echinoderms. Ann. New 



York Acad. Sci. Bd. 12. 



1907. The Apodous Holothurians; a Monograph of the Syn- 



aptidae and Molpadidae, etc. Wash. B.C. SwAth Inst. Gont. to Knowledge 

 35. 

 1921. The Echinoderm Fauna of Torres Strait; its composition 



and its origin. Papers Dept. Mar. Biol. Carnegie Inst. Wash. Bd. 10. 

 — ■ 1922. The holothurians of the genus Stichopus. Bull. Miis. 



Comp. Zool. Cambr. 65. 

 1926. Notes on a collection of echinoderms from the Austral- 



ian Museum, Sydney. Records Austral. Museu7n Sydney, Bd. 15, No. 2. 

 1928. Echinoderms from Australia. Mem. Mus. Comp. Zool. 



vol. 55. 



1946. The Echinoderm Fauna of Australia; Its Composition 



and its origin. Carnegie Institution of Washington Publication 566, 

 Washington, D.C. 



