mostly in the South Island; Oamaru; The Chatham, Auck- 
land and Campbell Islands. 
It has also a very wide distribution in the Southern 
Hemisphere, and has been recorded from the Falkland 
Islands, Chili, Peru, South Africa and Fiji. This so-called 
circum-austral distribution can be better understood by re- 
ferring to a physical map of the world and taking note of 
the direction of ocean currents in the Southern Hemisphere. 
The figurehead of a wooden sailing vessel, wrecked off the 
Falklands, drifted during the course of some months to 
the western coast of Australia, and, although no details 
appear to have been reported of any marine life carried by 
this particular piece of wreckage, it is easy to surmise how 
different living forms can be transported for great distances 
by similar agencies. It is an interesting fact that it is 
mostly in colder latitudes of these islands that this species 
of mussel is met with. 
MODIOLUS ATER (modiolus, a small measure, a 
drinking vessel; ater, black).—A small black and very 
smooth, shiny mussel with blunt beaks, sculptured with 
concentric growth lines. The epidermis is thick and folded 
inwards at the margins, making a narrow black polished 
edging to the interior. Inside, purplish or bluish white, 
and iridescent. Found in great numbers covering rocks 
between tide marks, on groins, jetties, piers, wharves, and 
all timber permanently standing in water. Generally only 
one inch in length, it may attain twice that size. 
Found throughout New Zealand. Mount Maunganui; 
Auckland Islands. 
MODIOLUS AUSTRALIS (modiolus, a small measure, 
a drinking vessel; Australis, southern).—A chestnut-brown 
mussel with a leathery epidermis, produced into a scanty 
and bristly fringe at the posterior end of the valve, which 
is the part furthest away from the hinge. The interior is 
cream colour, the dorsal portion of a brownish purple, 
sometimes not shading off into the cream-coloured portion, 
but presenting a decided and sharp line of demarcation. 
The region of the ligament is coloured a dark bluish purple, 
bound on either side with a narrow strip of pearl. It 
attains a length of four inches, usually much less. On 
rocks below low-water mark, but procurable at spring tides. 
Throughout New Zealand. Mount Maunganul. 
MODIOLARIA IMPACTA (modiolus, a small meas- 
ure, a drinking vessel; impacta, fixed or pressed together ). 
—A thin bivalve of unusual shape, not unlike a hazel nut, 
89 
Plate X 
No.8 
Plate X 
No. 9 
Plate [IX 
No. 14 
Sea Shells 
of New Zealand 
