Page:Beautiful·Shells·of·New·Zealand-Moss-1908.pdf/20

 over portions not covered with growths, so as to reduce the risk of the colour fading. When the animal is removed and the growth cleaned away, wash, scrub, and dry, as with dead shells.

Shellfish are sometimes obtained by dredging with a naturalist’s dredge, or by diving for them, or lifting them out of the water with instruments such as hay forks and hooks. Sandy beaches and banks yield many of the most beautiful specimens, but only with experience will the collector be able to identify the marks of the syphons of the various shellfish. Nearly all shellfish that burrow have two syphons, or tubes, which they push through the sand. The water is drawn down one syphon and up the other; and as it passes through its stomach the mollusc absorbs the animal and vegetable particles in the water. Some of these shellfish live feet below the surface of the sand; some, such as the common cockle, only a fraction of an inch. Apparently even cockles do not come to the surface, except to die. Some instinct seems to urge a shellfish, when sick unto death, to save its fellows from infection by leaving the common shelter. Cockles found on the surface are to be avoided as unhealthy, and, unless they die naturally, are soon killed by the carnivorous shellfish. It does not take one of the whelk family long to bore a hole in the centre of the cockle shell. It knows too much to risk having its radula, or tongue, nipped off by putting it between the partly-open valves of the dying cockle. The end of the syphon, which projects from the sand, is like a miniature sea anemone. Each sand-burrowing shellfish has a different shaped end to its syphon, and the skilled collector can tell at a glance what shellfish is down below. If he can grip the syphon with his hand he will have no difficulty in digging up the shellfish, even such a deep-living one as the Panopaea (Plate VIII., Fig. 3), one of which was captured by Mr. C. Spencer on Cheltenham Beach, near Takapuna Head, in Auckland Harbour. I believe this was the only Panopaea captured in New Zealand in situ, and was about eighteen inches below the surface of the sand at half-tide mark. If he miss gripping the syphon he will probably lose the shellfish; as it can burrow nearly as fast as a man can dig with his hand. A beginner cannot do better than take a small spade, and walk along a sandy beach at low water. As the tide begins to rise, and the buried shellfish feel the water, he will see the sand moving, or showing signs of life; and if he digs quickly enough he may unearth rare and beautiful specimens for his cabinet.