[ 37 ] 



ANATOMY OF THE PEARL OYSTER. 



(Margaritifera vulgaris, Schum.). 

 [With NINE PLATES.] 



The Anatomy of the Ceylon Pearl Oyster has never been adequately investigated. 

 L. G. Seurat, in his little book ' L'Huitre Perliere,'* gives a short account of the 

 structure of one of the large pearl oysters of the Pacific, Meleagrina margaritifera, 

 and makes a few remarks upon the shell and some of the organs of the much smaller 

 Ceylon pearl oyster (then known as M. fucata). Several writers on Molluscan 

 morphology have described special points in our animal or closely related species. 

 For example, GROBBENf gives some information as to the heart, PelseneerJ as to 

 the branchise and nervous system, E,idewood discusses the gill structure in Avicula 

 argentea and various species of Meleagrina, and Thurston|| gives a few figures and a 

 brief description. 



The works of Garner, Rawitz, Thiele and Biedermann all contain useful 

 information bearing more or less on our subject. H. L. Jameson^ has recently 

 written on the identity and distribution of the mother-of-pearl oysters and has 

 determined that the Ceylon form commonly known as Avicula fucata is in all 

 probability the Perlamater vulgaris of Schumacher, belonging to the modern genus 

 Margaritifera, and must therefore be known as Margaritifera vulgaris, Schum. 



In the following accountof the anatomy of the Ceylon pearl oyster, while the aim 

 has been to give a fairly complete description of all parts of the body, those organs 

 have been treated most fully which are of greatest importance in connection with the 

 operations of the pearl fisheries and of the oyster culture. And, as in biological 

 work generally Structure should never, if possible, be dissociated from Function, 

 what information could be given in regard to the uses of the parts has been supplied 

 when discussing the anatomy. 



I have included as much as possible from our field- notes in regard to the habits and 

 actions of the living animal as seen in our experimental tanks, since it is a rare event 



* ' EiKycdopeVlie Scientifiquc des Aide-memoire.' Masson et G' c , Paris, 1901. 



t 'Arbeit. Zool. Instit, Wien,' Band VII., p. 410. 



| 'Archives de Biologic,' tome XL, p. 198, 1891. 



'Phil. Trans.,' B, vol. 195, 1903, p. 147. 



,i 'Madras Government Museum Bulletin,' No. L, 189-1, p. IS. 



51 'Proc. Zool. Soc.,' April 16, 1901, p. 372. 



