The animal on the cover of Programming ASP.NET AJAX is a black murex snail
(hexaplex nigritus). The black murex is found off the coast of California and Mexico.
As it ages, its shell turns from white to predominately black. However, pure white or
black shells are very rare. Mature black murexes are about 6 inches (15 centimeters)
Black murex snails are carnivorous gastropods. Their diet is composed of bivalve
mollusks, including oysters, clams, and sea anemone. Gastropods kill their prey by
various means, including smothering, tearing, or boring into the shell by using an
acidic mucus to weaken the outside surface.
The murex snail played a crucial role in the culture and trade of the ancient Phoenicians.
They crushed the murex in order to extract a purple-red secretion used to dye
fabric. It is estimated that some 10,000 snails were needed to dye one toga. As a
result, only royalty could afford the precious dye for clothing. When the dye was
combined with silk imported from China, the purple garments were worth more
than their weight in gold. Purple has since been equated with royalty, but the red of
papal robes and the blue in the flag of Israel are also derivative of murex snail dye.