Please help me identify this seashell from Asia

[greengreen]

Hi,

I just got this polished seashell dish. Its dimensions are: 9.75" x 6".

Could anyone help me identify the name of this seashell (the main seashell, NOT the added leg seashell) please? I really appreciate it.

<img src="http://img.auctiva.com/imgdata/8/1/5/0/0/7/webimg/207646112_o.jpg" alt="http://img.auctiva.com/imgdata/8/1/5/0/0/7/webimg/207646112_o.jpg" style="border:0" />

<img src="http://img.auctiva.com/imgdata/8/1/5/0/0/7/webimg/207646155_o.jpgg" alt="http://img.auctiva.com/imgdata/8/1/5/0/0/7/webimg/207646155_o.jpgg" style="border:0" />

<img src="http://img.auctiva.com/imgdata/8/1/5/0/0/7/webimg/207646133_o.jpg" alt="http://img.auctiva.com/imgdata/8/1/5/0/0/7/webimg/207646133_o.jpg" style="border:0" />

<img src="http://img.auctiva.com/imgdata/8/1/5/0/0/7/webimg/207646179_o.jpg" alt="http://img.auctiva.com/imgdata/8/1/5/0/0/7/webimg/207646179_o.jpg" style="border:0" />