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to contain a small percentage of muriatic acid. Such powers have some shellfish of dissolving or altering the form of their shells, that the Cyprae, or Cowry, our representative of which family is the Trivia australis (Plate VII., Fig. 29), not only can dissolve the inner part of its shell, but can deposit new layers on the outside. This Murex lives on sand in the open ocean, and is found in the North Island only.
MUREX OCTOGONUS (Plate II.).—Fig 2 is a slightly longer shell than the Murex zelandicus, and, like it, is found only in the North Island. But in place of being round or oval, this shell is octagonal, from which peculiarity it derives its name. The grooves that cross the shell are deep, and between them are small curved spines. The shell is thick and solid, the exterior being reddish white, sometimes stained with brown. There is a smaller variety of this shell, darker in colour and with more numerous spines than the photographed specimens shown.
MUREX EOS (Plate II.).—Fig. 3 is a beautiful pink shell, about an inch long. Dead shells only have been found, and a good specimen is much prized. None of the Murex family are common, and they are seldom found alive. Murex eos, although existing in Tasmania and Australia, has so far been found in New Zealand nowhere South of the Bay of Islands.
MUREX RAMOSUS.—Two specimens of this well-known Island shell have been found in Tauranga during the last five years. One excellent specimen, 8½ inches long, was a live shell, and is now in the possession of Mrs. T. M. Humphreys, of Tauranga. An illustration of this shell will be found on Plate X., Fig. 10.
TROPHON STANGERI (Plate II).—Fig. 4 is a rough grey shell, with a dark purple interior. It is covered with parallel ridges and lines, which are known as varices, very thin and close together, and running from the apex to the mouth of the shell. It is over an inch in length, and usually found on cockle banks in harbours.
TROPHON AMBIGUUS (Plate II.).—Fig. 5 is in shape very like the Murex stangeri, but twice the dimensions, and can be easily distinguished, as the varices are much higher and further apart; besides which they cross one another at right angles, forming a perfect network, and the interior is pinkish brown. This shell is found on ocean beaches, as well as on cockle banks.
