124 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.2 



are numerous waterfalls. This beautiful and picturesque island, covered 

 with dense tropical vegetation, has been the object of much interest due 

 to the legends of treasure which is reported to have been hidden there 

 by pirates. 



Schmidt** in his discussion of the zoogeography of Cocos Island con- 

 cluded that the few native species of vertebrates, four land birds and 

 two lizards, are mostly distinct from those of any other part of the 

 world, but that they are alh'ed to Central America, the nearest land 

 mass. The forms are such that transport or passage'^ across the inter- 

 vening ocean is understandable. He further stated: "The species have 

 probably arisen in consequence of geographic isolation, without indica- 

 tion of adaptive change or changes due to natural selection." 



Papers on the marine mollusks have been published by von Martens,^ 

 Pilsbry and Vanatta,^ Biolley,i^ Dall,^^ Hertlein,i- and Tomlin.^s 'p^g 

 majority of the marine species from Cocos Island are the same as those 

 found on the mainland of the adjoining coast. 



Pfeiffer,!'* von Martens,!^ Kobelt,i« Dall,i^ Ancey,^^ Biolley,!^ and 

 Pilsbry-*^ have published information dealing with the land shells and 



^ Schmidt, K. P., Essay on the Zoogeography of the Pacific Islands, in 

 Shurcliff, S. N. Jungle Islands. Putnam Press, New York, 1930, pp. 278-280. 

 See also Biolley, P., Mollusques de L'lsla del Coco. Mus. Nac. de Costa Rica, 

 1907, 30 pp. 2 maps. 



"^ For a general discussion of the faunas and floras of oceanic islands, see 

 Gulick, A., Biological Peculiarities of Oceanic Islands. The Quarterly Review 

 of Biology, vol. 7, no. 4, 1932, pp. 405-427. 



s von Martens, C. E., Die Meeres-Conchylien der Cocos-Insel. Sitz. Ges. 

 Naturf. Freunde zu Berlin, Jahrg. 1902, no. 6, pp. 137-141. 



9 Pilsbry, H. A., and Vanatta, E. G., Proc. Washington Acad. Sci., vol. 4, 

 1902, p. 559. 



10 Biolley, P., Mollusques de L'lsla del Coco. Mus. Nac. de Costa Rica, 

 1907, pp. 19-30. 



ilDall, W. H., Bull. Mus. Comp. Zool., vol. 43, no. 6, 1908, pp. 436-437; 

 Proc. U. S. Nat. Mus., vol. 38, 1910, p. 225; Proc. U.S. Nat. Mus., vol. 51, 1917, 

 p. 578. 



12 Hertlein, L. G., Nautilus, vol 46, no. 2, 1932, pp. 44-45; Proc. Amer. 

 Philos. Soc, vol. 78, no. 2, 1937, pp. 303-312, 1 pi. 



13 A few species have been cited from Cocos Island by Tomlin, J. R. le B., 

 in Jour. Conch., vol. 18, no. 6, 1927, pp. 153-170; no. 7, 1928, pp. 187-198. 



i^Pfeiffer, L., Symb. ad Hist. Helic, sect. 3, 1846, p. 66. 



15 von Martens, E. C, Sitz. Ges. Naturf. Freunde zu Berlin, Jahrg. 1898, 

 no. 9, pp. 156-160; Jahrg. 1902, no. 3, pp. 59-62. 



16 Kobelt, W., Nach. Deutsch. Malak. Ges., Jahrg. 31, 1899, pp. 26-28. 



17 Dall, W. H., Proc. Acad. Nat. Sci. Philadelphia, vol. 52, 1900, pp. 96-99. 

 iSAncey, C. F., Journ. de Conchyl., vol. 51, no. 2, 1903, pp. 97-104. 



19 Biolley, P., Mollusques de L'lsla del Coco. Mus. Nac. de Costa Rica, 

 1907, pp. 13-19. 



20 Pilsbry, H. A., Manual Conch., sen 2, vol. 18, 1907, pp. 325-330. 



