of its being a few shades darker or lighter, merely a ques- 
tion of food and locality. 
The S. Zealandica is found at Howick; Auckland; 
Mount Maunganui. 
GADINEA NIVEA (gados, a fish; nivea, snowy ).—A 
small white limpet-like oval shell with the apex almost 
central, or slightly placed to the rear. The sculpture con- 
sists of radiate ribs, of which there are about forty, with 
concentric growth lines fairly well defined. There is a 
wonderful variety in the shape of the shell. It may be 
depressed and almost flat, or it may be highly elevated. 
Some are shaped like the flatly conical straw hats of the 
Japanese coolies; others, more elevated, are either the 
counterpart of ancient Roman helmets or like little models 
of sou’-westers, with a rounded crown and a wide brim, 
each individual limpet differing from its neighbour, ac- 
cording to the amount of room available for expansion. 
Again, some are as thin as a visiting card, and others are 
quite six times that thickness. The thick ones are to be 
found among those hampered for room, and so crowded 
together that the margins press against each other, and as 
a result assume a hexagonal form, exactly as the cells of 
a honeycomb which, instead of being circular, become six- 
sided by reason of the remarkable ingenuity of the bee in 
economising space. The thick six-sided shells of the Gadi- 
nea nivea have been selected from a huge colony of these 
creatures at Mount Maunganui and recorded as the Hip- 
ponyx hexagonus, a mistake which would never have been 
made had the proper precaution of studying a long series 
been adopted. As a matter of fact, the Hipponyx does 
not occur in New Zealand at all, and the name must be 
deleted from our native fauna. 
If exposed to particularly rough seas, and living upon 
tugged and uneven surfaces, the shells are most irregular 
in shape and outline, a fact clearly proved on comparing 
some west coast specimens with those obtained from Tau- 
ranga, 
The interior is smooth, shining, and white, and there 
is a well-marked siphonal groove running upwards from 
the front border towards the apex. The muscle scar, 
which is roughened, is horseshoe-shaped, with the toe di- 
rected backwards and the two free ends clubbed. The 
margin of the shell. is crenulated or crimped inside. It is 
rather a rare shell, about five-eighths of an inch long and 
half an inch wide. Found on rocks, between tide marks, 
generally in dark and almost inaccessible places, in the 
same localities as the Slit limpets. 
83 
Plate VIII 
No. 30-30a. 
Sea Shells 
of New Zealand 
