SHELLS AND MOLLUSCOUS ANIMALS. 219 



hooks, by means of which they catch and tear their 

 food. 



That very common shell, the Muddy-red 

 Trochus (Trochus Ziziphinus) , has, as well as the 

 other species of the genus, an in- 

 mate similarly formed to the peri- 

 winkle, and like it, is a spiral shell. 

 It is of a dull grey hue, marked 

 with dashes of a reddish flesh- 

 colour, or brownish pink. It is 

 generally about an inch long. This 

 genus received its name from the 

 resemblance of the shells to a top. We have 

 several native species, some of them among our 

 commonest shells. 



The grey Trochus (Trochus cinerarius) is very 

 much smaller than the last-named kind, and is of 

 an ash colour, varied with darker spots, .and its 

 spire is not so pointed; while the little spotted 

 Trochus (Trochus maculata) is smaller still, and is 

 called by children on the coast, Pepper-and-salt 

 shell, perhaps because its colour resembles that of 

 the cloth of that name, worn some years since. 

 They are both very frequent on our sandy 

 shores. 



A singular shell of this genus, called the Carrier 

 shell (Trochus phorus), a native of Eastern shores, 

 is in great request among conchologists. It 

 attaches to its outer surface, as it increases in size, 

 a variety of foreign objects, as stones, shells, and 

 corals. The species of Trochus are very numerous, 

 and some of them may be found in almost all seas. 

 Fossil Trochi too are very abundant ; some of 

 them of existing species, as our muddy-red and 

 grey kind ; others of species now extinct. 



