The shells were individually at pretty low resolution, so I decided to try to make one of my own. I started by selecting foreground and background colors from one of the shells and then made alternating horizontal bands of color. I added some white color noise and applied a wind filter, then made some white bands perpendicular to the first bands. I then applied a distort>wavy filter, and used a perspective transform to make a progression of smaller to larger bands. I selected a triangular section of this and added light and dark contours by painting in white and black on a 50% gray layer set to overlay. The inside of the opposite side of the shell was made in much the same way with different colors. I use liquify to bend the corners of the top layer around the inside.

The text is from the display in the background of the original. The font is Minion Pro with an emboss layer style.