210 



THE SEA SHORE 



same family, but in some respects they resemble the Myacidce or 

 Gapers. The shell is oblong rather than triangular, and gapes at 

 both ends ; and the animal buries itself deep in sand or mud, 

 principally in the estuaries of rivers, from low-water mark to a 

 depth of about ten fathoms. The shells are not very common objects 

 of the shore, for they are found only in muddy places, and those of 



3 4 



FIG. 142. 1. Lutraria elliptica. 



2. PART OP THE HINGE OF Lutraria, SHOWING THE CARTILAGE PIT. 



3. Macro, stultorum. 4. INTERIOR OF SAME SHOWING PALLIAL LINE 



the commonest species (L. elliptica) are too large and heavy to be 

 washed ashore in the sheltered estuaries where they abound. 



"We now leave the burrowers, to consider a family of molluscs 

 that move about somewhat freely by means of a flattened tongue- 

 shaped foot, and which only rarely fix themselves in any way. The 

 shells of the group are popularly known as Venus shells, probably 

 on account of the beauty of some of the species, and the family 

 in question as the Veneridee. 



