396 THE DOLPHIN-SHELL. 



by a deep groove along its centre so as to form two lobes, each of which is alternatefy 

 slid forward in the act of walking. The animals are mostly possessed of rather bright 

 colors, 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 per- 

 fectly its spiral structure. 



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

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

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

 bleared in proportion as they approach the mouth. These are the colors of the speci- 

 men 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 gray, 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 our 

 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 TURBO VERSICOLOR, which is brought from Southern Amer- 

 ica, 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 projec- 

 tions. 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. 



ANOTHER beautiful species of Trochus is the NILOTIC TOP, a shell which is remark- 

 able 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 handsome as well as a rare species, and is notable for the bold 

 rounded projections which radiate from the whorls. Its color 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 resem- 

 blance 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 oper- 

 culum is horny, flat, and spiral. When the shell is inspected from below the centre, 



