LIMA. 267 



ligamental area is of moderate breadth, and the beaks 

 prominent and rather broad. 



Three-quarters of an inch in breadth, and half an inch 

 in length, are the dimensions of rather large examples. 



Animal shaped like the shell ; it is of a colour varying 

 from pale orange to pale crimson, the mantle margins being- 

 reddish white ; they are quite open all round in front and 

 at the sides, plain at their free edges and fringed with 

 three rows of long tentacular filaments at their junction 

 with the shell : the innermost series of these is longest. The 

 body is white ; the foot small, cyhndrical, and furnished 

 with a conspicuous byssal groove. 



The habits of this species have been observed by Mr. 

 Clark, who has seen it " repeatedly fix itself by fine byssal 

 filaments, then detach itself and move with the greatest 

 rapidity, crossing a dish of six inches' diameter whilst one 

 could be counted. The rounded extremity is that which 

 is in front and the beaks behind, when the animal moves : 

 this operation is performed by placing itself on the whole 

 length of the straighter or ventral range, having the dorsal 

 or rounded side uppermost ; then opening its valves wide, 

 it suddenly flaps them together, and so on, and thus moves 

 with extraordinary celerity ; not using the foot, which 

 appears to this animal to serve rather for fixing itself than 

 for motion." 



This is the most generally distributed of our British 

 Litnas, though from the delicacy of its shell, it is difficult to 

 obtain perfect specimens. Herm at low water (S. H.) ; 

 Portland Island in fifteen fathoms, Penzance in twenty 

 fathoms, Anglesey in ten to twenty- five fathoms, gravel 

 (M'Andrew and E. F.). Exmouth (Clark); Isle of Man 

 in twelve to twenty-five fathoms, on Nullipore ground and 

 Scallop banks (E. F.) ; rare at Scarborough (Bean); and 



