Sea Shells 
of New Zealand 
Plate II 
No. 14-14a, 
greenish-brown spiral univalve, commonly known as the 
Cat’s-eye shell. The external surface is fibrous in appear- 
ance, due to the well-marked growth lines; the interior is 
pearly, smooth and glistening. ‘The operculum is a round 
and thick shelly structure, beautifully coloured green 
and white. It is found on rocks between tide marks, and 
sometimes attains a diameter of two and a-half inches, 
The young Turbo of this species differs considerably from 
the adult form, and was at one time described as a distinct 
species. It has a thick, smooth, pale or dark olive-green 
shell, with three prominent keels or ridges running spirally 
round the body whorl, and a single row of rather flattened 
beaded sculpture round the upper surface of the whorls 
of the spire. Very juvenile shells have the whole of the 
ribs completely furnished with small hollow spines, jutting 
outwards and horizontally forwards in the direction of the 
aperture. This sculpture is generally worn off in all speci- 
mens over half an inch in width, and rarely persists in half- 
grown shells. Many juveniles also show two spiral ribs 
on the base in addition to the typical three. Quite infan- 
tile shells are flat—that is to say, all the whorls are on the 
same plane. It is interesting to collect all sizes of the Turbo 
smaragdus, not overlooking dead shells, so that the various 
stages of growth may be studied, when it will be readily 
seen how the third and lowest rib becomes obsolete, what 
becomes of the middle one, and how the remaining rib 
loses the pristine beauty of youth. Young shells are in- 
variably more beautifully coloured and sculptured than 
older ones, which, through the attrition caused by sand 
constantly washing over them, lose some of their epidermis 
—a somewhat make-shift term for periostracum,—and so 
become encrusted with coralline growths and other foreign 
matter. Further disfigurement is due to the work of bor- 
ing worms, sponges, and shell-boring molluscs. 
Between the years 4500 3.c. and 5000 B.c the operculum 
of the Turbo was pierced for wearing as a charm or amu- 
let, by the Egyptians, for protection against injuries and 
diseases of the eye. 
The Turbo smaragdus is quite common, and is found 
throughout New Zealand. Mount Maunganui. 
ASTRAEA HELIOTROPIUM (Astraca, Star-maiden, 
the goddess of Justice; heliotropium, of heliotrope colour). 
—The Circular Saw shell. A comparatively rare and 
beautiful spiral univalve, also known as a Calcar (Latin, 
a spur), from the hollow spines springing from the peri- 
phery of the body whorl, which give the shell a resemblance 
to the rowel of a spur. The colour of the young shell is 
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