CYAMIUM. 261 



shaped at the posterior angle, and gradually and slightly curved 

 on the dorsal side ; umbonal area prominent : beaks blunt and 

 calyciform, not much recurved, almost contiguous, and often 

 eroded ; they are placed very excentrically, being close to the 

 anterior side : ligament cylindrical, horncolour, extending from 

 the beaks towards the posterior or longer side, and rising above 

 the level of the dorsal line: hinge-line obtusely angular: 

 hinge-plate narrow, occupying rather more than one-third of 

 the circumference : teeth, in the right valve one extremely 

 thick and blunt cardinal, which is often bifid or trifid ; in the 

 left valve two erect and recurved cardinals ; all these teeth 

 are in adult specimens deeply and beautifully tinged with 

 purple, and project from under the beaks; laterals hardly 

 distinguishable from the hinge-plate and apparently forming 

 part of it : inside glossy, but not nacreous : pallial scar entire : 

 muscular scars distinct ; the posterior is the larger of the two. 

 L. 0-07. B. 0-09. 



HABITAT : Gregarious among seaweeds and under 

 stones at low-water mark, and in the laminarian zone, 

 on sheltered parts of our coasts from Unst to Alderney. 

 Mr. Grainger has noticed it in the so-called " alluvial " 

 deposit at Belfast. This species has a high northern 

 range, but its southern distribution is limited. Fabri- 

 cius, Moller, Morch, and Torell found it in Greenland, 

 and the last-named conchologist (as well as Steenstrup) 

 in Iceland ; Loven and others have recorded it from the 

 Scandinavian coasts, Recluz and Mace from Cherbourg, 

 and myself from the Gulf of Spezzia. Stimpson says 

 that it lives in Massachusetts Bay, " abundantly in June, 

 about the roots of fuci, which cover the boulders at 

 Point Shirley." 



According to Fabricius this tiny shell has a Green- 

 landic name, " Ipiksaunarak." On certain parts of our 

 coast it occurs in countless multitudes. Mr. Hyndman 

 estimated that 35,000 shells were contained in the sto- 

 mach of a single mullet caught in Larne Lough, where 

 I have noticed them covering the leaves and stalks of 



