112 NEW ZEALAND NATURE-STUDY BOOK 
If a few drops of hydrochloric acid be poured on the shell 
the effervescence caused will show that it consists of 
carbonate of lime. 
Voluta pacifica is another suitable form for study. The 
shell, which is thick and strong, has a smooth polished 
surface. In some forms a row 
: RY of short projections runs along 
Le’ the upper whorls, gradually 
& gt a), disappearing as the apex is 
>) 2 Peg Pi reached. The body whorl - is 
Z » long, and surmounted by a short 
L. spire. ‘The mouth is long and 
_——_ a% oval, The outer lip is broken 
3| YZ on its lower margin by a shallow 
= 7 notch through which the tube or 
S U. siphon which conducts the water 
S GH 
ia] Uj 
to the gills passes. The inner 
lip along the columella or axis 
of the shell shews a number of 
Fig, 74.—Voluta Pacifica. spiral folds) A few drops of 
hydrocholoric acid poured on 
the surface will ew that, like the other shells described, 
it consists of carbonate of lime. 
A comparison and contrast. An examination of 
these two forms will show that each consists of a thick 
strong single shell, spirally coiled, and composed of carbon- 
ate of lime. The strength of the shells will suggest their 
habitat—in rock-pools and amongst boulders where they 
are constantly dashed about by the waves. Hach shell is 
the product of a marine animal, and consists of a body 
whorl anda spire. The shells differ in the shape of the 
mouth in the nature of the lip, in the size of the body 
whorl relative to that of the spire, in the markings on the 
surface, and in other minor details. 
