132 C O N C H O L O G Y. 



I think myfelf further juftified in creathig 

 a new order*. 



Now to the fyftem or method. 



I divide all teftaceous animals into the 

 three ufual general divifions of Univalves, 

 Bivalves, and Multivalves, 



Each of thefe three general divifions con- 

 tains many families, genera, and fpecies. 



Mr. Tournefort well obferves, there ought 

 to be certain principles or chara£lers in 



^ The numerous clafs of Echini moft certainly are 

 cruftaceous, are conjoined to the Star fifli, or at leaftarc 

 Jffines, They have no common charader with the 

 Teftacea, but their living in the fea, and partaking of 

 the natiwe of marine animalt. It is not clear, that 

 they do not in certain periods even change their Shells, 

 as crabs and lobfters. How elfe can we account for 

 their increafe ? The form and fubftance of thefe Shells 

 render it extremely difficult to account for this, with- 

 out fuch a fuppofition — they are neither Univalves 

 nor Multivalves. They are a clafs apart, as much as 

 the Allaci, &c. 



Some of the Sea Stars confift of many cruftaceous 

 parts ; their food, their progreflion are, fimilar, and 

 muft be conjoined, Corio-cruflacea, 



3 every 



