88 PHYTOPHAGA. 



2. LITTORINA muriatica. 



Turbo muriaticus Linn. 



Cyclostoma acutum Drap. 



Which has been placed by the latter author as a 

 fresh-water species, is abundant on many parts of our 

 coasts. It is nearly allied to Littorina ulvce. Hart- 

 mann has formed a genus called Uydrobia from these 

 small Littoringe. 



