76 CONCHOLOGIA CESTRICA. 
within bluish-white; operculum with the centre de- 
pressed. H. 28, W. 15, aperture H. 15, W. 9, mill. 
M., decisa, —{W.G. B.]} 
Fig, 153. 

Station, creeks and ponds. Chester County; abun- 
dant. 
Lingual Dentition of M. decisa. Operculum of M. decisa. 
Fig. 154, Fig, 156, 
GO 
Genus LIOPLAX, TrRoscHEL, 1857. 

Animal of L. subcarinata, male and female. —[W. G. B.| 
Fig, 156, 
g 
pf My 
Female. Male. 
Shell, thin, ovate, turreted ; whorls rounded, carinate. 
