How Animals Work. 



by a flat lamina, with its edges bent round so as to 

 meet along the under side. The interior of this pro- 

 boscis is lined with delicate cilia, by whose constant 

 vibrations a current of water is drawn into the tube, 

 and poured over the surface of the gills for the purpose 

 of respiration. Let us now look at the vivid hues of 

 these organs. The foot, which expands to so great a 

 length and breadth behind the shell, is of a buff or 

 pale orange grounS colour, delicately striated with lon- 

 gitudinal undulating veins of yellowish white. The 

 mantle, which embraces the shell, is of a pellucid olive, 

 thickly mottled and spotted with black, and studded 

 with glands protruding through its substance of light 

 yellow, and it is edged with a narrow border of red. 

 The proboscis is vermilion-red, varying in brilliancy in 

 different individuals. The tenticula are of a paler tint, 

 of the same colour, speckled with yellow. Such, then, 

 is the beauty of the animal which inhabits this familiar 

 and plain little shell a beauty of which those who 

 know it only in cabinets can hardly form an idea ; which, 

 as one gazes on it placidly gliding along, one cannot 

 help an emotion of surprise that such an amplitude of 

 organs can be folded within the narrow compass of the 

 shell, and protruded through so contracted an aperture." 



The univalves which build the largest and most 

 massive shells are the Helmet (Cassis) and the Conch 

 (Strombus) shells, which frequently attain a length of 

 ten or twelve inches or more, and a weight of over 

 four pounds. Large numbers of them are imported 

 into Europe annually, and are used in the production 

 of cameos, an art in which the Italians excel. 



Now let ug consider a few of those Molluscs that 



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