CONCHOLOGIA CESTRICA. 



THE 



MOLLUSCOUS ANIMALS 



AND THEIR 



SHELLS, 



OF CHESTER COUNTY, PA. 



WILLIAM D. HARTMAN,' M.lC 



AND 



EZRA MICHENER, M.D. 



' An undevout philosopher is mad. 



PHILADELPHIA: 



LAXTON, REMSEN & HAFFELFINGER, 



624, 626 & 628 MARKET STREET. 



1874- 



