80 THE NAUTILUS. 
the tide. Their tracks may often be traced more than twenty 
feet. 
Cerithidea scalariformis habitually crawls up the stems of grass, 
and lives the greater portion of the time out of water. 
The Cerithium nigricans live in large colonies between high and. 
low water marks. 
Cardium isocardia craw]s out of the sand soon after the water dis-- 
appears; but they do not travel far. When put ina basin of salt 
water, they often close their shells with a lively snap. 
Fasciolaria distansis the only shell, observed by the writer, which 
feeds upon the Vermetus nigricans colonies, into the tubes of which 
it inserts a long proboscis. 
Fasciolaria tulipa is the only shell, in the knowledge of the wri- 
ter, which makes an effort for freedom when held in the hand. It 
projects its body out of the shell and “slashes ” about its long and 
sharp operculum with sufficient force to occasionally bring into view 
some of the blood of its captors. 
The Oliva literata often lives in colonies. It emerges from the 
sand soon after the disappearance of the water, and crawls for a 
considerable distance. 
Sigaretus lives usually under the sand, but at low tide it often 
comes to the surface; but it does not proceed far. It is a favorite 
morsel for the “littoral pigs,” who root it out of the sand with 
avidity. 
Lucina jamaicensis affects the muddy sand. They lie deeply 
buried under the surface, and seldom are seen on top of the mud. 
The Lucina tigrina probably possesses the same habit, as many dead 
shells are found in places where few are seen living. 
The Pholas costata, I presume, lives below low water mark, as their 
shells are washed ashore in some places in great quantities. They 
also live in colonies in the muddy sand flats that are dry at low 
tide. 
The sheli reposes about 10 to 12 inches below the surface, but 
the animal can project its long siphon to the surface, through a hole 
permanently kept open. 
In a future article we propose giving the results of observations 
upon the feeding habits of some Florida mollusks. 
