PATELLA RADIANS (Plate IX., Fig. 34), and PATELLA STELLIFERA (Fig. 35) are two representatives of the many species of beautiful limpets we have. The limpet family has not had the attention of our scientists which it merits. The shells vary so much that it is extremely difficult to classify them. In the attempt to do so, Patella radians has been subdivided into five sub-species, but even this division is not a success. We have few more beautiful or interesting shells than limpets. We have them of every shape, and from three inches in width down to microscopic specimens. The limpet resides on one spot, but moves about with the rising tide in search of the vegetation on which it lives. This it mows down with its long scythe-like tongue, and, when satisfied, it returns to rest in its favourite spot. Limpets have the reputation of being indigestible, if not poisonous, but this is due to the head not being removed before the mollusc is eaten. If the head be removed carefully, the tongue, or radula, which is usually the length of the shell itself, will come with it. The 2000 or so fine teeth found on the average limpet's tongue will quite account for the belief that the fish is poisonous, as great irritation must be caused by these sharp little teeth. The Patella stellifera is usually found in caves or sheltered places amongst rocks exposed to the ocean swell. It is always covered with a coraline growth, usually of a pinkish tint, which growth has to be removed before the markings can be seen. Stars of all shapes, regular and irregular, will be found on the spire of the Patella stellifera. There is a reputation yet to be made by the man who can classify our New Zealand limpets. The Maori name for the limpet is Ngakihi, or Ngakahi, which name is also used for the Crepidula family.
PECTEN MEDIUS (Plate X.).—Fig. 1 (late Pecten laticostatus) is the well-known scallop found among the grass banks in harbours as well as in the open sea. The shells are sometimes five or even six inches across, and of all conceivable colours and mixtures of colours. The valve shown in the plate is the flat valve, which looks like a fan. The other valve, which is rounded, makes a good substitute for a scoop. This Pecten, or scallop, is the most delicate of our edible shellfish, but is never seen in our markets. The animal moves by opening its shell, slowly swallowing a large quantity of water, and in a rapid manner ejecting it, thereby pushing the shell backwards. The Maori name is Tipa.
PECTEN CONVEXUS (Plate X.).—Fig. 2 is a much smaller shell than No. 1, and quite as brilliantly coloured. The valves are nearly equal in shape. It is found amongst rocks, but is usually dredged in comparatively shallow water.
PECTEN ZELANDIÆ (Plate X.).—Fig. 3 is a still smaller shell, and the most brilliantly coloured of our Pecten family. The valves are similar in shape, and covered with short spikes. It has only the one ear, or lug, at the hinge end, but sometimes a portion of the ear is found on the other side. This shell lives amongst rocks, or in sponges, or on the roots of kelp, in sheltered or fairly sheltered portions of open beaches. It is found attached to the rocks by a byssus, or beard.
PINNA ZELANDICA (Plate X.).—Fig. 4 is generally known as the Horse Mussel. It is usually found amongst the grass, about low water mark, on sandy beaches, especially those containing a proportion of mud. The natives call it Hururoa or Kupa, and in some places it is a staple article of diet with them. This horse mussel is found in certain spots in great numbers, and is then useless for a cabinet. The collector should look for odd scattered specimens. As a rule, only about half an inch of the shell will be found protruding above the beach, in very shallow water, but in deep water more of the shell will protrude.
MYTILUS LATUS (Plate X.).—Fig. 5 is the ordinary mussel, with a green epidermis, and the part near the hinge is usually eroded, as shown in the plate. It grows to a considerable size in New Zealand, being sometimes 8 inches in length, and is found in enormous quantities in favoured localities on rocks or attached by its beard in clusters to old cockle and other shells on the banks. About twenty years ago hundreds of acres of banks between the town of Tauranga and the sea were in one season colonised by mussel spawn, and although the mussel was before that date a rare thing on these banks, yet after the colonisation the banks were simply a mass of mussels, and the water, being only from one to two fathoms deep at low spring tide, they were easily procurable. On the other hand, banks near Kati Kati Heads, that were covered a few years ago, are now without mussels. This is probably due to some disease breaking out through overcrowding. The Mytilus edulis (not shown on plate) is a purplish shell, of similar shape and habits to the above, but much smaller in size. The Maori name for a mussel is Kuku or Porope or Tore-tore or Kutai, and for the smaller mussels Kukupara or Purewa or Toriwai.
MYTILUS MAGELLANICUS (Plate X.).—Fig. 6 is a bluish mussel, with prominent ribs, as shown in the plate. The interior is white, and the shell is found up to three inches in length.
VOLSELLA AUSTRALIS (Plate X.).—Fig. 7 (late Modiola australis) is a rough-looking, uneven shell, of a pale chestnut colour. It usually has a hairy-looking growth near the edge, as shown in the plate. It is found up to four inches in length.
There are two other of the Volsella family in New Zealand, neither of which are illustrated. The Volsella fluviatilis, a shiny, black mussel, shaped like the Edulis, and about 1-1/2 inches long, found in brackish water, is the most common. The inside is bluish-white, and purplish round the margin.
OSTREA ANGASI (Plate X.).—Fig. 8 is a mud oyster, of which those dredged at Stewart's Island are the largest we have. Fine specimens were found in Ohiwa Harbour prior to the Tarawera eruption of 1886, but the deposit from that eruption appears for the time being to have destroyed them. There must be some large banks of this oyster in the Bay of Plenty, judging by the number of dead shells washed up in places; but, although I many times used the dredge while in Tauranga, I never had the good fortune to find one of the banks. Cartloads of the shells were at times washed up on the beach between the town of Tauranga and the entrance to the harbour.