208 



nexed arrangement, it will be known at once what 

 sort of instruction is to be expected from his la- 

 bours. 



Testaceological writers are to be classed as fol- 

 lows : 



1. Those who have written generally of Con- 

 chology. 

 II. Those who have described a single genus, 

 family, or species. 



III. Those who have described the shells of 



certain parts of the globe. 



IV. Those who have described museums or 



collections of shells. 

 V. Those who have described minute shells, 



microscopic subjects. 

 VI . Those who have detailed the wonders of 



the science. 

 VII. Those who have written on the anatomy 



of testaceous worms. 

 VIII. Those who have written on their phy- 

 siology. 

 IX. Those who have invented or followed a 



systematical arrangement of shells. 

 X. Those who have commented on the works 



of others. 

 XI. Those who have published plates illus- 

 trating Conchology. 



