LEDA. 229 



size of individuals is rarely above half an inch long, and 

 rather more than half that measurement broad. 



The description by Fabricius of his Area minuta, drawn 

 up solely from two engorged, and probably eroded, indivi- 

 duals, fairly enough agrees, except in the number of teeth, 

 with our British species ; the shell, however, identified with 

 it by the Northern conchologists, who naturally have better 

 data for determining the Boreal species, than we possess, is 

 allied, but very distinct. 



Animal of a white colour, oblong and pyriform ; the 

 margins of the mantle are freely open except posteriorly, 

 and are fringed or denticulated by a series of five very 

 short filaments. The siphons are united for more than half 

 their lengths, considerably prolonged, slender and smooth : 

 the branchial one is shorter than the anal, and the latter 

 has a quadrangular orifice with apiculated angles. The 

 foot is oblong, compressed, white, deeply grooved, and 

 capable of expansion into a creeping disk, with crenated 

 margins. 



This species, though found in the south, is rare there, 

 and becomes plentiful only on our northern coasts. Herm, 

 Sandwich, Weymouth, but scarce (S. H.) ; Exmouth, 

 in twenty fathoms, very rare (Clark) ; Tenby (S. H.) ; 

 Fishguard (Jeffreys) ; ten fathoms, Milford Haven, twenty- 

 five fathoms Anglesey, and fifteen to twenty fathoms, 

 gravel, Caernarvon Bay (M'Andrew and E. F.) ; Scar- 

 borough (Bean) ; from deepest water, frequent on the 

 coasts of Northumberland and Durham (Alder) ; through- 

 out the Hebrides and Clyde district in various depths of 

 water, from fifteen to ninety and one hundred fathoms. 

 Off the Mull of Galloway (Beechey) ; and Sana Island 

 (Hyndman); in deep water on the East coast from the 

 Dudgeon to Orkney (Thomas). 



