1901.] itfOTHER-OF-PBAEt OYSTERS. 37S 



The Fiji shell of the trade, from Fiji, is also nearest to the 

 Australian and New Griiinea varieties. I Lave not seen a sufficiently 

 lai'ge series of examples from Eotuma and the Line Islands to be 

 able to say if shells from these loeahties are distinct varieties. I 

 am inclined to think that, like the Fiji shell, they Avill prove to be 

 nearest to the Australian form, but leading towards var. cumingii 

 Eeeve. The Black-edged Banda shell of the trade, to which form 

 I believe Linnaeus's type belongs, occurs throughout the Malay 

 Archipelago. It is more smoky and less lustrous than the Aus- 

 tralian shell, but the differences are slight. China {M. sinensis 

 Leach, ? var. dist.) ; Andaman Islands (sp. in B. Museum approx- 

 imating to var. zanziharensis); Ceylon (occasionally found in Grulf 

 of Manaar and Palk Straits); Maldive Islands (Mr. Stanley 

 G-ardiner informs me that it is fished by natives in Addu Atoll 

 and occurs elsewhere throughout the archipelago). 



Var. b. M. margaritifera Zanzibar ensis, n. var. 



TypeB.M.No. 1901.2.28.30; Zanzibar, A. van Noorden, Esq. 



" Zanzibar shell " and " Madagascar shell " of the trade. 



Ground-colour reddish grey, rufous tints prevailing. Eadial 

 rows of spots cloudy reddish yellow, rather indistinct. Margin of 

 the nacre copper-coloured ; the cupreous tint often pervading the 

 nacre throughout. Form and size as in M. m. typica. 



Geographical Distribution. Zanzibar, Madagascar and E. coast of 

 tropical Africa; Amirante Islands (B.M.) ; Bazaruto Is. (B.M.); 

 Mauritius (B.M.) ; Eodriguez (B.M., approaching to var. erythrce- 

 ensis) ; Seychelles (B.M., pres. Sir A. Gordon ; too young to 

 refer definitely to any variety). 



Var. c. M. margaritifera persica, n. var. 



Type B.M. No.'l901.2.28.23; Persian Gulf, pres. A. van 

 JSoorden, Esq. 



The " Bombay shell " of the trade ; so called because largely 

 shipped via Bombay from Persian Gulf. 



The posterior margin of the nacre foi-ms a right angle with the 

 hinge, as in M. maxima. Colour greyish or greenish brown, 

 lighter than in typica, with radial bands of yellowish white. Inside 

 of lip light brown ; margin of nacre bi-assy yellow or golden. 

 The nacre lacks the somewhat steely sheen characteristic of the 

 species, being whiter, often with a slight roseate tint, and ap- 

 proaching in lustre to that of Margaritifera maxima. Size as in 

 M. m. typica. 



Geographical Distribution. Persian Gulf, largely fished in the 

 neighbourhood of the Island of Bahrein. There is an example in 

 the British Museum from Adam Bank, near Gettar, Persian Gulf. 



Var. d. M. margaritifera erythroiensis, n. var. 



Type B.M. No. 190L2.28.24; Eed Sea, pres. A. van 

 Noorden, Esq. Savigny, 1811, pi. 11. fig. 7. 

 The " Egyptian shell " of the trade. 



Approximating to var. persica in form and colour, but less 



25* 



