396 THE DOLPHIN-SHELL. 



groove along its centre so as to form two lobes, each of which is alternately slid forward 

 in the act of walking. The animals are mostly possessed of rather bright colours, some 

 specimens being wholly grass-green, others brown dotted with green, and others with the 

 foot spotted with white or reddish violet. The operculum is very hard and shelly, 

 slightly convex, and, when viewed from the inside face, exhibits very perfectly its 

 spiral structure. 



The colour of the Australian Pheasant-shell is very beautiful, consisting of delicate 

 wavy pencillings and mottlings of pink, carmine, grey, and brown. These marks are 

 more decided and the carmine purer towards the apex of the shell, the colours becoming 

 bleared in proportion as they approach the mouth. These are the colours of the specimen 

 from which the figure was taken, but this is an exceedingly variable species, the tints 

 differing greatly in tone and distribution, and some specimens being almost wholly 

 ochrous and grey, with hardly a trace of the beautiful carmine and rose-pink of other 

 individuals. 



THE little pointed shell on the left of the illustration is the well-known TOP of oui 

 own shores. 



This little shell, which is here represented of the natural size, is one of the most 

 plentiful species of the British coasts, and may be found by hundreds either crawling 

 among the sea-weeds at low water, or flung upon the sands by the tide. The shell of this 

 creature is beautifully pearly, and when the outer coating is removed the iridescent nacre 

 below has a very lovely appearance. Jewellers and lapidaries employ these shells largely 

 in their art, polishing them carefully and then stringing them together so as to form 

 bracelets and necklaces, or affixing them as ornaments to various head-dresses. Another 

 little shell, called TUKBO VERSICOLOR, which is brought from Southern America, is also 

 used for similar purposes. The specimens of Top-shells which are found in the sands 

 are seldom quite perfect, the apex of the spine being usually worn down and rubbed so 

 as to display the sub-lying nacre. 



About one hundred and fifty species of Trochus are known, some of them attaining 

 considerable dimensions, and all possessing shells of exceeding beauty. The peculiar 

 form of the animal is shown in the illustration. The tentacles are rather long, and the 

 eyes are seen at the extremity of the little footstalks, at their base. The neck-lappets are 

 rather large, and the sides are furnished with lobes and tentacular projections. The 

 operculum is horny, flat, and spiral. Trochi are found all over the world, and have a 

 considerable water range, being captured at all depths, from the shallow waters of the 

 shore to a depth of a hundred fathoms. 



ANOTHEK beautiful species of Trochus is the NILOTIC TOP, a shell which is remarkable 

 for the rich contrast of scarlet flashes on a white ground. One of the rarest species of this 

 genus is the IMPERIAL TOP (Trochus imperialis), a shell which has hitherto been found 

 only in New Zealand, and may probably be confined to that strange land. It is a hand- 

 some as well as a rare species, and is notable for the bold rounded projections which 

 radiate from the whorls. Its colour" is violet-brown above and white below. Some 

 authors, however, separate this shell from the Trochi, and place it in a separate genus, on 

 account of the toothed whorls. 



The DOLPHIN-SHELL affords another instance of the entire discrepancy between the 

 shell and the popular name that is given to it, this species bearing no more resemblance 

 to a dolphin than to a roach, a cow, or a peacock. 



Twenty species of this genus are known, all being inhabitants of the hotter seas, and 

 found chiefly near the tropics. There are but few whorls in this shell, and they are formed 

 in so singular a manner, that they look as if they had been crushed down by a heavy 

 weight and thus prevented from rising into a pointed spire. In this species the tentacles 

 are surrounded with blunt spines, but in others they are edged with sharp teeth or with 

 wrinkled projections. The aperture is round and pearly, and the operculum is horny, 

 flat, and spiral. When the shell is inspected from below the centre, or " umbilicus " 



