IXTRODUCTIOX. XI 



surface, form a fruitful soil for the nourishment of vegetation. 

 The character of the testaceous deposits, too, enable geologists, as 

 those who study the nature and structure of the earth are termed, 

 to come to important conclusions on many points connected "\Tith 

 the subject of this investigation. And if we include, as the subject 

 of our book allows, the inhabitants of shells, how wide a field of 

 usefulness opens before us. How many thousands of our industrious 

 population depend wholly, or in part, upon the capture and sale 

 of shell-fish for their support. In some parts, as the western 

 and northern Islands of Scotland, they have in times of scarcity 

 afforded sustenance to the dwellers on the bleak and barren shores, 

 who but for them must have perished. But of all this we shall 

 have more to say when we come to describe the diflferent members 

 of the testaceous family. We will now offer a few remarks upon 



THE INHABITANTS OF SHELLS; 



Which belonging to that division of Natural History caUed the 

 Mollusca, from the Latin Mollis — soft; these Molluscous animals, 

 then, are animals having a soft body, and no internal skeleton. 

 You may be quite sure that a Molluslc will never break its bones, 

 because it has none to break; it has a shell, however, which may 

 be broken, at least in some cases, for aU Mollusks have not snug 

 habitations of the kind; but wander about the Aiatery or earthy 

 world in which they live, quite naked; such as the sea and land 

 slugs, and some worms, leeches, etc.: but with these we have 

 nothing to do, our present subject including only a part of 



MALACOLOGY, 



another member of that queer ology family, deriving its name 

 from two -Greek words signifying soft, and a discourse; hence it 

 means a discourse upon soft, or soft-bodied, animals, that is mollusca. 

 It is only a part then of Malacology that we have to do with; 

 that part which relates to the sheU-inhabiting mollusks, and strange 

 creatures enough some of these are. We will have a look at 

 them presently; just now it will be sufficient to observe that the 

 ■mollusca testacea, or soft-bodied animals, furnished ^\-ith shells, 

 possess the power of exuding, that is, discharging from various 

 parts of their bodies a sticky kind of fluid, which mixing with 

 the chalky matter collected from the water, and becoming hard, 

 forms, in process of time, the shelly covering which is at once a 

 dwelling and a defence for the inhabitant. 



Miss Pratt, in her delightful book on "Common Things of the 

 Sea Coast," observes of these shells that, "We gather up those 

 which we find, and lookin<i- at their structure would fain knovr 



