14 



XXIV. VALVATA. VALVE-SHELL. 



So named from the valve or lid which covers the 

 orifice of the aperture. 



114. Valvata obtusa. Stream Voice-shell. 



115. Valvata Spirorbis. Crested Valve-shell. 



116. Valvata Plan orbis. Depressed Valve-shell. 



117. Valvata minuta. Flat Valve-shell. 



XXV. PALUDINA. MARSH-SHELL 



So named from their locality in marshes, ditches, and 

 slow streams. 



118. Paludina vivipara. Viviparous Marsh-shell. 



119. Paludina acbatina. Ayate Marsh-shell. 



1 20. Paludina impura. Covered Marsh-shell. 



121. Paludina similis. Similar Marsh-shell. 



122. Paludina viridis. Green Marsh-shell. 



123. Paludina Stagnorum. Stagnant Marsh-shell. 



XXVI. NERITINA. FRESH-WATER 



NERITE, 



A diminutive of Nerita, the ancient name of a sea 

 shell. 



124. Neritina fluviatilis. River Neritine. 



