hells 
oe ee Zealand 
Plate VI 
No. 13 
Plate VI 
No. 14 
round shell with a raised apex more or less in the centre, 
There is a spiral twist, and a small portion of the under 
surface is covered over with a thin plate-like structure. 
The upper surface is marked with spiral lines, the apex 
is smooth and whitish in colour; the under surface smooth 
and glossy, similar in colour to the upper surface. It is 
about four-fifths of an inch in diameter. 
Found throughout New Zealand. Hauraki Gulf; Little 
Barrier Island; Mount Maunganui; Lyttelton Harbour; 
Stewart Island. 
CREPIDULA COSTATA (crepidula, a small sandal; 
costata, ribbed).—The Slipper limpet is a strongly built, 
boat-shaped shell with well-marked rough and regular ribs 
running from the rear of the shell, which is narrow, to 
the front, becoming wider and spreading out in conformity 
to the general outline. Nearly half of the under surface is 
covered in with a thin deck-like structure. The shell is 
arched, and may be yellowish brown, light or dark, chest- 
nut or almost white in colour. About two and a-half 
inches in length by one and a-quarter inches wide. The 
Slipper limpets have a partiality to fixing themselves to 
the valves of the large Horse mussels, and to rocks at low- 
tide mark. 
Found throughout the North Island. Mount Maunga- 
nui. 
CREPIDULA CREPIDULA (crepidula, a small san- 
dal).—This is another Slipper limpet, with a very thin 
white shell, rather oval in shape, curved on the flat, sup- 
posed to resemble a finger nail, and having a small pocket 
on the underside. The under surface is very smooth and 
glossy, the supper surface matt or dull. These limpets are 
found mostly upon the Turbo smaragdus or Cats’-eye shell, 
and in the aperture of the Siphonalias or Spindle shells. 
In the former case they are narrow and boat-shaped, with 
a fine beak-like prow or apex; in the latter, more flattened 
and broader, varying in shape according to the contour and 
surface of the shell upon which, or in which, they happen 
to reside, a condition common to all species of the limpet- 
like molluscs. The naming of this shell has been com- 
mented upon as being a “silly reduplication recently sub- 
stituted for Crepidula unguiformis,” but this is not the 
case. The name Patella crepidula, literally the slipper 
limpet, was assigned to it in the year 1764 ap. by Linné 
(Linnaeus), the renowned Swedish naturalist. Lamarck, 
sixty years later, described the same species as Crepidula 
unguiformis, which is correct, so far as the first or generic 
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