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ETHALIA ZELANDICA (Plate VI.).—Fig. 7 (late Rotella 
zelandica) is a well-polished, smooth shell, washed up in large 
numbers on the ocean beaches. The colours of the upper side 
vary, but are usually chestnut or purple waving lines on a yel- 
lowish-white ground. On the base is a circular band of purple 
round the columella, which is white. The interior is nacreous. 
Occasionally a shell is entirely pink, and then the circular band 
on the base is pink also. The largest shell I have seen was nearly 
one inch across, and, being very flat, would be only half an 
inch high. They appear to live in sandy ground, below low 
water mark in the ocean; and a dredge if drawn over one of their 
favourite spots will be filled with them. I have dredged half a 
bucketful at one cast between Karewa and Tauranga in five 
fathoms of water. The former name was Rotella zealandica, and 
Rotella, meaning a little wheel, well described the appearance 
of the shell, the waving line representing the spokes. 
NATICA ZELANDICA (Plate VI.).—Fig. 8, a yellowish or 
reddish-brown shell, with chestnut-brown bands, the interior being 
pale brown, the mouth and its vicinity white. It is a clean, 
bright little shell, upwards of an inch across. Those in the 
ocean are lighter in colour, and larger and more solid than those 
found in harbours. As the tide falls in harbours, they conceal 
themselves near low water mark, especially in the vicinity of 
marine grass banks. When the tide is rising on a warm, sunny 
day, they spring out of the sand, dropping sometimes two or 
three inches from where they had been concealed. The operculum 
is horny, with a shelly outer layer; and the animal is prettily 
mottled and striped red and white. 
There are two other Natica found in New Zealand, neither 
of which exceeds one-third of an inch across, and in shape are 
very like the N. zelandica. The Natica australis is a brown 
or grey shell, and the Natica vitrea is white. 
NERITA NIGRA (Plate VI.).—Fig. 9 (late Nerita saturata) 
is a heavy, solid blue-black shell, with a whitish interior. This 
sombre-looking member of a handsome tropical family (of which 
the bleeding tooth Nerita is the best known) is sometimes over 
an inch in length, and found in large numbers clinging to the 
surf-beaten rocks of the North Island, quite up to high water 
mark. The operculum is shelly and prettily mottled with purple. 
This shell will stand boiling water, and, in fact, boiling water 
is required to kill the animal, which is quite as tenacious of life 
as an oyster. The Maori name is Mata ngarahu. 
