—Walter Thornbury, “Shells.”
SNAILS OF THE OCEAN.
Many of my readers have doubtless spent some of the vacation months at the sea shore and have wandered over the beach at low tide picking up shells and other objects left by the receding ocean. They have also, I am sure, peered into the little pools of water left on the beach and have watched with interest the captives imprisoned therein, hermit crabs, fiddler crabs, sea anemones, sea worms and snail shells. It is with the latter that the present article will deal.
The stretch of beach which is uncovered twice a day by the receding of the water is called “between tides,” and is inhabited by a host of animate creatures, chief among which are the mollusks. The marine snails outnumber all of those which we discussed in the last article, and their shells are far more beautiful, those found in the tropics having the most gaudy colors imaginable. The animals are formed on the same plan as those of the fresh-water snails, although each family has some peculiarity not shared by its relatives. All live in the water and breathe air through that medium by means of gills, similar to the second class of fresh water snails mentioned in the last number. They are found in all parts of the world, those of the tropics, however, being the most brilliantly colored. While the majority of species live either between tides or near low water, there are not a few which live in the abysses of the ocean, and have been dredged from the bottom of the sea at a depth of two thousand, seven hundred and forty fathoms, or, to put it more plainly, over three miles. The average depth at which mollusks are found in any number is about one thousand fathoms. The variability of marine snails is so great that we shall be able to call attention to but a limited number of typical forms.
Among the best known of the marine snails are the Tritons, a family of mollusks living in tropical seas. Their shells are generally large and highly-colored and variously ornamented with short spines and knobs. One species, the Triton tritonis, is among the largest of mollusks, measuring eighteen inches in length. One of the smaller Tritons is pictured on the plate. Another shell familiar to those who have visited Florida is the Fasciolaria or banded snail, which attains a length of three inches and is very prettily banded and dashed with color. A near relative of this species is the giant banded shell (Fasciolaria gigantea), which is the largest of all marine snails, growing to a length of nearly two feet. This species is found plentifully on the southern Atlantic coast of the United States, being particularly abundant about the coral reefs of the Florida Keys.
A genus of mollusks with light horn colored shells, and inhabiting the cold waters of the Arctic seas, is the Buccinum, or whelk. In various parts of Great Britain it is known as “buckie” and “mutlog.” The Buccinum delights to burrow in the sand, like the moon shells (Natica), and frequently nothing but the end of the siphon can be seen, the latter protruding from the sand to enable the water to enter the animal to furnish the necessary oxygen. The whelk is used economically, both for food and bait. One ingenious method of catching them is to fasten a dead fish of good size in a wire basket and to allow it to rest on the bottom for a short time; when taken up it is covered with large, fat whelks. This fishery in Great Britain is fully as valuable as our oyster fishery, the annual income from this industry reaching to thousands of pounds sterling. The animal is also one of the principal baits used in cod fishing. A related genus, the neptune shells (Neptunea), is also eaten by the poorer people and makes a good codfish bait. The two kinds of whelk (Buccinum and Neptunea), are termed, the first the white whelk and the second the red or almond whelk, probably on account of the colors of the two shells. In the Shetland Islands the red whelk is used as a lamp, being suspended by strings from a nail, the mouth placed uppermost and filled with oil.
MARINE SHELLS.
FROM COL. CHI. ACAD. SCIENCES.
First row: Cypraea pantherina (Red Sea) Cassis flammea (Bahamas) Conus marmoreus (Polynesia) Second row: Buccinum undatum (U. S.) Fasciolaria distans (U. S.) Third row: Tritonium olearium (Naples) Oliva irisaus (Amboina) Voluta musica (West Indies) Fourth row: Ianthina communis (Atlantic Ocean) Chiton squamosus (Jamaica) Lottia gigantea (California) Nassa glans (Amboina)
The basket shells or dog-whelks are among the most numerous in individuals of all the marine snail shells, the common black whelk (Nassa obsoleta) being the most common of all the mollusks. The writer has seen a mud flat at low water literally paved with the shells of this snail, there being millions of the little creatures crawling about. The shells of this family are frequently very handsome, being latticed by the crossing of lateral and longitudinal lines. They are mostly of small size, scarcely exceeding an inch in length, many of them being much under these dimensions. The animal is very rapid in movement and leaves a distinct track in the mud, which will frequently end at a little pellet of mud, which, upon examination, will disclose the little animal nicely concealed beneath.