sidered it advisable to describe them in parallel columns, 
so that by comparing them step by step identification may 
‘be simplified. 
DIPLODONTA DIPLODONTA 
GLOBULARIS: ZELANDICA: 
Colour, pellucid white. Opaque white. 
Very rare. Not rare. 
Very thin. Fairly solid. 
Globular. Less globular. 
Sculpture, very fine con- Rather coarse concentric 
centric growth lines. growth lines, 
Slightly over an inch across About seven-eighths of an 
and conspicuously less inch across and practical- 
from hinge to ventral _ ly the same in length. 
border. Bay of Islands; Hauraki 
Mount Maunganui; Banks Gulf ; Auckland Harbour; 
Peninsula ; Oamaru ; Banks Peninsula; Mount 
Stewart Island. Maunganui; Chatham Is- 
lands. 
MYLLITA STOWEI (melletes, a loiterer; Stowe, the 
naturalist)—An uncommon and beautiful little bivalve, 
white or greyish white, thin and translucent; half an inch 
in length from the anterior end to the posterior end, and 
slightly more than half that measurement from the beaks 
to the ventral margin. It is almost symmetrical in shape, 
and both valves are alike. The sculpture consists of dis- 
tinctly raised ribs, narrow above and broader below, ar- 
ranged chevron fashion, the apex of each chevron being 
in the same straight line, descending from the beaks to 
the centre of the ventral margin. The intervals between 
the ribs are wider than the ribs themselves, and are com- 
pletely stippled with minute pits, which can be made out 
with a good hand lens. As the sides of the chevrons are 
curved gracefully inwards and prolonged into a sharpened 
point above, the whole effect is decidedly pleasing. The 
interior is shining and white, showing the impression of the 
external ribs as grooves. The margins are crimped by the 
ends of the ribs. 
Hauraki Gulf; Bay of Islands; Mount Maunganui; 
Cook Strait; Foveaux Strait. 
ROCHEFORTIA RENIFORMIS (Rochefort, the nat- 
uralist; reniformis, in the form of a kidney)—A small 
bivalve, scarcely exceeding a quarter of an inch across, of 
a light brown or whitish colour, with well-marked distant 
and equally-spaced concentric ribs crossed by fine radiate 
97 
Plate IX 
No. 12 
Plate IX 
No 19 
Sea Shells 
of New Zealand 
