48 RAMBLES IN SEARCH OF SHELLS. 



carries with it a certain amount of authority; for 

 amongst those who assisted the author in its com- 

 pilation will be found the names of two well-known 

 naturalists Dr. J. E. Gray, whose edition of 

 Turton's " Manual of British Shells " will always be 

 a text-book for conchologists, and Mr. Thomas Bell, 

 the well-known author of " British Quadrupeds," 

 whose published researches in various branches of 

 zoology can never be too highly estimated. 



In this list we find ten species of Planorbls 

 mentioned as occurring in the neighbourhood of 

 London ; but one of these is mentioned twice under 

 different names, marginatus and complanatus ; while 

 fontanus and imbricatus of Cooper are respectively 

 nitidus and nautileus of modern conchologists. The 

 Hampstead ponds are referred to as the haunt of 

 several species of Planorbis, such as carinatus, 

 vortex, contortus, and spirorbis ; and the Green- 

 wich Marshes, and ditches about the Surrey Canal 

 near Deptford, are said to have yielded carinatus, 

 marginatus, nautileus, corneus, contortus, albus, 

 and spirorbis.* Mr. A. F. Sheppard, in a list of 



* P. spirorbis may often be found on grass in wet mea- 

 dows. 



