476 FISSURELLIDJi. 



until of late years has it been taken alive, and British cabi- 

 nets were for a long time supplied with specimens from the 

 pleistocene beds of the Clyde. Mr. Smith, of Jordan Hill, 

 was the first to maintain its existence in the living state in 

 the British seas. Except on the Northumberland coast, 

 where it has been taken at Cullercoats, by Mr. Alder, and 

 in fifty fathoms sixty miles to the east of the north coast 

 of Durham, by Mr. King, its localities are all Scottish. It 

 ranges in depth from twenty to one hundred fathoms, and 

 occurs at intervals throughout the Hebrides, and off the 

 coast of Zetland (M'Andrew, Jeffreys, E. F.). In from 

 thirty to eighty fathoms on the west coast of Orkney ; 

 alive, on stones, in thirty-five fathoms, Buchanness, and in 

 sixty fathoms, Troup Head (Thomas). 



It is a species essentially of northern origin, and has now 

 its chief habitats in arctic and boreal seas, extending along 

 the coast of Greenland, and down those of Boreal America 

 to Cape Cod. It dates its origin from the pleistocene epoch, 

 and can only be regarded as a lingerer in our existing 

 seas. 



EMARGINULA, Lamarck. 



Shell conical, with an elevated slightly recurved entire 

 vertex (obliquely subspiral in young specimens) turned to- 

 wards the posterior end ; aperture expanded oval ; surface 

 with radiating and cancellated striae or ribs ; emarginated 

 in front by a slit which runs for some distance up the shell, 

 and is continuous with a closed groove which reaches the 

 apex ; interior without a partition ; muscular impression 

 crescentic, with deeply incurved extremities, interrupted in 

 the region of the head. 



Animal with a short muzzle terminating a tumid head 



