74 ^hell Life 



intersections. It is a purely northern species, being 

 found round the coasts of Scotland and Shetland, 

 extending south only as far as Yorkshire and Durham ; 

 occurring in muddy gravel at depths ranging from 

 7 to 90 fathoms. Large specimens may measure as 

 much as 2i inches. It is known to northern fisher- 

 men as the " Corduroy Mussel." 



These are the only genera of Filibranchiata repre- 

 sented on our coasts. 



