[13] FISHERIES OF THE UNITED STATES. 197 



cene of South Carolina. Like the F. carica and 8. canaliculatus, Lunatia 

 lieros and Neverita duplicata are generally found in company; having 

 the same habits and appearance, to the casual observer, they are fre- 

 quently confounded one with the other, and are usually known to the 

 fishermen and long-shoremen as "Sea-Snails," and sometimes as " Wink- 

 les " or " Periwinkles." On account of their similarity in distribution 

 and close relationship in habits, they are considered together. 



The Lunatia lieros is found on nearly all sandy shores, in pure water, 

 and apparently prefers the open coast and heavy surf, growing under 

 those conditions to a larger size than elsewhere. It «is by no means 

 as large as the Fulgur or Sycotypus, but has been known to reach 

 five inches in length by nearly four in breadth. When in motion the foot 

 and soft parts of the body are protruded to a remarkable extent, and 

 spread out so broadly as to almost conceal the shell. The foot is large, 

 concave below when expanded, and when extended beneath the sand 

 affords the animal a secure anchor or hold; it is the organ by which 

 the animal burrows for protection or prey. Both the Lunatia lieros and 

 the Neverita duplicata are destructive, boring round holes through bi- 

 valve shells by means of small teeth on the lingual ribbon, and then 

 sucking out the contents of the shells. Nor do they confine their oper- 

 ations to the bivalves, but attack univalves, not excepting their own 

 young, as well. Neverita duplicata differs from its usual associate in 

 being found less frequently on the outer beaches and growing more 

 abundantly, though not to so large a size, elsewhere. It is a more 

 southern species than the Lunatia lieros, and is not common north of 

 Cape Cod. The egg cases of both species are often met on mud and 

 sand flats at low water, and are very curious. They consist of a broad, 

 thin ribbon of sand, coiled in a circle. The ribbon is composed of in- 

 numerable little cells, each containing eggs, and surrounded by fine 

 sand cemented together by mucus. The cells can easily be seen by 

 holding the ribbon to the light, and for the same reason given for de- 

 stroying the egg-capsules of the Fulgur and Sycotypus, these egg-cases 

 should meet a similar fate when encountered. 



While both L. lieros and N. duplicata are found on sandy and gravelly 

 shores, their natural ground, where they exist in greatest abundance, is 

 the shelly bottoms of oyster beds and similar areas. 



Crepidula plana, Say. 



Crepidu la fornicata, Lamarck . 



These two species are neither directly useful nor harmful, but when 

 present in large numbers they form one of the indications of the health 

 of an oyster-bed and are therefore exhibited. The former is known as 

 the " Slipper-Shell" and the latter as the " Boat-Shell." Both are found 

 from Massachusetts to Florida, and on the northern shores of the Gulf 

 of Mexico. 



