Marine Pearls, 75 



embraces a number of separate families, while these 

 in their turn comprise numerous genera. 



The family Aviculidce embraces nearly all the 

 true marine Pearl- bearers, or Pearl oysters. It takes 

 its name from the genus Avicula ('*a little bird") 

 so named in consequence of the winged shape of 

 the shell. The largest quantity of medium sized 

 Pearls are derived from the Meleagrina fucata 

 (Gould) but the largest Pearls and mother-of-pearl 

 shell from the Meleagrina margaritifera (Linnaeus.) 

 Meleagrina is now commonly regarded as a sub-genus 

 of Avicula, and the word is therefore often written 

 within brackets following the name of the true genus, 

 thus : Avicula {Meleagrina) margaritifera. Although 

 a great number of Pearls are supplied by various 

 other species, yet the larger quantity which the 

 Meleagrina fucata produces, and the fine quality of 

 Pearls as well as shell yielded by the Margaritifera^ 

 justify us in referring to them at some length, and 

 adopting them as types of the Pearl-bearers. A 

 description of them, therefore, will hold true of 

 all the others, except in certain scientific points of 

 difference, which are of more interest to the marine 

 zoologist than to the lover of gems or to the general 

 reader. 



The Pearl-oyster, Meleagri^ia fucata, is much 

 much smaller than the M. margaritifera ; seldom 



