Aan.tMag.Nai lb,d. Vol ll! Flllll. 



STRUCTURE OF SHELLS. 



MgJ 

 Decalcified 7n/rr0mtru- of Fmna 



Section of Shell of Finna. 



Iig.3. 

 Section of Nacre. 



^^ 



Sectoon of AyicuL-ai ^ ) iongicostaiB . 



■)i>wr^bY okt et Mi 



Section- of Lima, riidis 



