PLATE CL. 



It is evidently distinct from the Patella lacustris of Linnaeus, In 

 being of an oblong instead of ovate form ; and in having the pointed 

 vertex bending obliquely or to one side, instead of being centrical and 

 reflected back. The colour is variable, in some it is greenish, and in 

 others of a pale brovv^n. It is represented on our plate both of the 

 natural size and magnified. 



