426 
THE OCEAN WORLD. 
Indian Ocean, and is of a fine purple colour, varied with black above , 
the edges of the opening being of a coral red colour, the teeth ale 11 ® 
being white. 
The head of the animal is large and thick, furnished with 1"° 
conical elongated tentacles, at the base 
which are the eyes. The mantle is rang® 
outside the shell, falling back upon the edg eS 
of the opening, and terminating at its a® 
terior extremity in a long cylindrical chann® > 
cloven in front, and passing by a hollo 'V 
the base into the bronchial cavity. The t° 
is large, and furnished with a horny °P er 
culurn. 
These animals keep near the shore, & 
shallow water. They walk slowly, and °^ eI1 
sink themselves into the sand, where they p ie ^ 
upon small bivalves. They are not nuinero us 
hi species; but specimens from the Indi ftU 
Ocean are often large and beautifully marked. The shells of the ^ 
marked species are frequently used in India as lime, and employed !l 
mortar. . 
Our space only permits us to mention, among the more cun® ^ 
specimens, Cassis canaliculata (Fig. 264), two varieties of @ aSSl 
Madagascar iens is (Figs. 265 and 266), and the curious Cassis 
(Martini), Zebra (Lam.), or Zebra-marked Casque (Fig. 267). 
Fig. 267. Cassis zebra (Lamarck). 
und^ 
Purpura. 
The Purpuras have a classical name and history, having furnisl 
the Greeks and Romans with the brilliant purple colouring m® 1 
bed 
,tter 
Tb® 
which was reserved for the mantles of patricians and princes. 
Purpura is an oval shell, thick-pointed, with short conical spiral, as ^ 
Purpura capiUus (Fig. 268). In some it is tubercular or angular, 
last turn of tho spiral being larger than all the others put togetb®^ 
The opening is dilated, terminating at its lower extremity 111 ^ 
oblique notch. The columellar edge is smooth, often terminating 
a point ; the right edge often digitate, thick internally, and folded 0 
rippled. 
