Z*H -u CONCHOLOGY. 



A. Thi order ^intl tides all shells of a calca- 

 reous nature, that is, ^composed of carbonate of 

 lime mixed with some gelatinous or gluey matter, 

 and excludes such as are called crustaceous, in 

 the covering of which phosphate of lime is a 

 constituent part.* 



Q. Is there no other difference between tes- 

 taceous and crustaceous animals ? 



.A. Yes. Testaceous animals inhabit their 

 shells, to which they are partially attached ; 

 whereas the Crustacea make one with theirs, each 

 limb being invested with its own peculiar shield. 



Q. Are shells generally found on land ? 



A. Shells are either terrestrial, or found in 

 rivers, lakes, in shallows of the sea, or in the 

 deeper beds of the ocean. 



* By a reference to " Pinnock's Catechism of CHE- 

 MISTRY", the learner will become acquainted not only with 

 the terms here used, but with the principles on which the 

 combination of different substances are formed. In facf , 

 without some knowledge of the first elements of chemistry, 

 but little progress can be expected in the study of the 

 other sciences more or less dependent on it. 



