RISSOA. 91 



about five on the penult. I'liere are six remarkably 

 rounded volutions, which rather quickly attenuate to a 

 small but not very acute apical point, and are divided from 

 each other by a very profound but narrow suture. The 

 body is of nearly equal length with the spire ; its basal de- 

 clination is rapid but well arcuated. The aperture is rather 

 large than otherwise, and occupies from two-fifths to nearly 

 three-sevenths of the total length of the shell ; it is of a 

 rounded oval or suborbicular shape, and is quite smooth at 

 the throat. The outer lip is much arcuated, broadly 

 rounded at the base of the shell, and but little marginated. 

 There is a distinct but narrow pillar lip (oftentimes stained 

 with rufous or liver colour) which being a little reflected 

 and raised slightly at its curved outer margin, displays a 

 kind of umbilical crevice behind it. This minute shell 

 is hardly the tenth of an inch long, but rather more than 

 half that measurement in breadth. 



This species seems to range, though scarce in most 

 places, throughout the British seas. Plymouth, White- 

 sand Bay, Sandwich, Caswell Bay near Swansea (Jef- 

 freys); Exmouth (Clark); general in Devonshire (S. H.): 

 Scarborough (Bean) ; Isle of Man in twenty fathoms 

 (E. F.). " On corallines from ten to twenty fathoms water, 

 and in shell sand," frequent in Northumberland (Alder); 

 Berwick (Johnston) ; Aberdeenshire (M'Gillivray) ; along 

 with calathus in Orkney (Thomas) ; Lerwick, Zetland ; 

 Hebrides (Jeffreys) ; Bundoran and Kilkee on the west 

 coast of Ireland (W, Thompson) Bantry Bay ; Dublin Bay 

 (Jeffreys). 



There is so much confusion in the determinations of this 

 species and its allies, that we only give such localities as 

 have been rightly determined, and cannot venture on 

 foreign distribution. 



