One of the most attractive families of bivalve shells is the Veneridae, or venus shells, in which the shelly skeleton is ornamented by many bright colors, the patterns occurring in spots, dashes, zigzag lines and rays. Some varieties, as the spiny venus (Cytheria lupinaria) have the posterior end of the shell provided with long, sharp, curved spines, and the shell is also frilled in a beautiful manner. The common quahaug (round or hard-shelled clam), which is esteemed an article of diet on the Atlantic coast, and also to some extent in the interior, is a prominent member of this family. The Veneridae comprise some five hundred species, found throughout the world, and ranging from the shore between tides to several hundred fathoms in depth.

The family Cardiidae, the heart-shells or cockles, comprise some of the largest and most attractive of mollusks. The name Cardium, signifying a heart, is given them because of the close resemblance to that organ when a shell is viewed from the anterior end. These animals live in sandy or muddy bays, and generally congregate by thousands. In England, the edible cockle (Cardium edule) is considered quite a delicacy and thousands are used for this purpose. In our own country they are not generally eaten, except by the poor in Florida and in some places along the Gulf of Mexico, but the waters of Florida furnish some very handsome species, among them the Cardium isocardia figured on our plate, and the large Cardium magnum, which grows to a length of five inches and whose shell is ornamented by beautiful color patterns of brown and yellow. The foot of the Cardium is very peculiar, being shaped like a sickle, which enables the animal to pull itself along at a lively gait. A California cockle (Liocardium elatum) grows to a diameter of seven inches and would furnish a meal for several people.

In the family Tridacuidae size seems to have reached its limit. Tridacena gigas, found in the Indian Ocean, grows to a length of nearly six feet and weighs upwards of eight hundred pounds. Tryon records that a pair of these shells, weighing five hundred pounds, and, two feet in diameter, are used as benetiers in the church of St. Sulpice, Paris.

In some parts of the Indian Ocean, where pearl and sponge fishing are carried on, this clam (known as the giant clam), is a source of great danger to the divers, many losing their lives by being caught between the great valves of the shell, by either hands or feet. Many times a diver has amputated his fingers, hand or foot, and thus saved his life at the expense of one or more of these members.

The Tellinas (family Tellinidae) number among its five hundred or more species some very beautiful and interesting animals. They live for the most part buried in sand or sandy mud and are found throughout the entire world, Our common Tellina radiata, familiarly called sunshell, is found in Florida and the West Indies, and a: typical valve looks not unlike the horizon at sunrise, the brilliant rays of color spreading in different directions from a common center. At Newport, Rhode Island, the writer has gathered many thousand specimens of a beautiful little Tellen (Tellina tenera), whose shell measures scarcely half an inch in diameter and is tinted a lovely pink or pinkish white. The siphons of this family are very long and are separated, the upper one being half or three-quarters as long as the lower one, and the foot is rather long and pointed, admirably adapted for burrowing. The long siphons enable the animal to bury itself to quite a depth beneath the surface of the sand.

Closely related to the Tellinidae is the Psammobiidae, a characteristic form of which (Psammobia rubroradiata) is thus spoken of by Prof. Josiah Keep, in his interesting little book, "West Coast Shells" "But I wanted to see more of him, so I took a large jar, filled it half full of beach sand, added as much sea water as it would hold, and plunged my prize into the same. He rested quietly for a few minutes, and then began to open his shell and cautiously put out his two siphons. Soon afterward, from between the edges of his shells, came his big, white, spade-shaped foot. He drove it down into the sand, curved it a little to one side, gave a vigorous pull, and lo! his shell followed, though just why I could not clearly understand. Though the jar was large he reached the bottom before his shell was wholly covered with sand, and had to content himself with a half-above-ground tenement."