THE NATUKALIST'S GUIDE. 197 



difficult to remove them, as the animals will contract 

 and adhere very firmly. 



Zanthinid^.— These are thin little shells, highly 

 colored, which float on the open ocean by means of a 

 mass of vesicles. They are quite frequently driven 

 ashore during gales. I have seen vast quantities of 

 them on the Florida Keys. 



TKOCHiDiE are found in deep water, but, being small, 

 are frequently washed ashore on sand beaches. 



Paludixid^ are fresh-water shells, and are pro- 

 vided with an operculum, which appendage should be 

 preserved and kept with the shell, either by gluing 

 in place after the specimen is cleaned, or by wrapping 

 the shell in paper. The same remarks apply to all 

 operculated shells. 



LiTTOEiNiD^. — Small shells, found either in salt 

 water or near it, adhering to plants or shrubs. They 

 often occur in great numbers. I have seen the man- 

 groves of the Florida Keys covered with the Litorina 

 scalia, and the grass of the salt marshes at Cedar 

 Keys was covered with millions of Litorina litorea. 



TuKKiTELLiD^. — The so-called Worm-Shells occur 

 in great numbers on the Keys of Florida, growing 

 quite frequently in sponges. Other members of the 

 family are found in deep water. 



Cerithiid^ are found both in the salt water, often 

 at great depths, and also on salt marshes, near the 

 water. I have seen the ground absolutely covered 

 with some species. Others are found clinging to sea- 

 weeds. 



PyramidiellidtE. — These are all small shells, and 

 are either found clinging to seaweeds or sheltered by 

 other larger shells. 



Naticid^. — Members of this family are quite fre- 

 quently found on sandy beaches, or in shallow water, 



