46 
MYTILUS MAGELLANICUS (Plate X.).—Fig. 6 is a 
bluish mussel, with prominent ribs, as shown in the plate. The 
interior is white, and the shell is found up to three inches in length. 
VOLSELLA AUSTRALIS (Plate X.).—Fig. 7 (late Modiola 
australis) is a rough-looking, uneven shell, of a pale chestnut 
colour. It usually has a hairy-looking growth near the edge, as 
shown in the plate. It is found up to four inches in length. 
There are two other of the Volsella family in New Zealand, 
neither of which are illustrated. The Volsella fluviatilis, a shiny, 
black mussel, shaped like the Edulis, and about 14 inches long, 
found in brackish water, is the most common. The inside is bluish- 
white, and purplish round the margin. 
OSTREA ANGASI (Plate X.).—Fig. 8 is a mud oyster, of 
which those dredged at Stewart’s Island are the largest we have. 
Fine specimens were found in Ohiwa Harbour prior to the Tara- 
wera eruption of 1886, but the deposit from that eruption appears 
for the time being to have destroyed them. There must be some 
large banks of this oyster in the Bay of Plenty, judging by the 
number of dead shells washed up in places; but, although I many 
times used the dredge while in Tauranga, I never had the good 
fortune to find one of the banks. Cartloads of the shells were at 
times washed up on the beach between the town of Tauranga and 
the entrance to the harbour. 
The best known oyster in New Zealand is the Auckland rock 
oyster, the Ostrea glomerata (not shown in the plate), which is 
familiar to all who visit the seashore in the North. The Maori 
name for the rock oyster is Tio, and for the mud oyster Tiopara. 
PLACUNANOMIA ZELANDICA (Plate X.).—Fig. 9 is of 
the family known in England as the pepper and salt oyster. The 
lower valve is flat and has the large oval opening, shown in the 
plate, through which the foot of the animal protrudes and holds 
the shell on to the rock. The shell is thin and fragile, and is 
found in both Islands. Another shell of the same family, the 
Anomia walteri (not shown on plate), is found at the Bay of 
Islands, and is usually coloured bright yellow or orange. 
MUREX RAMOSUS, the last figure, is the latest addition 
to our New Zealand marine shells, and is described with the others. 
of the Murex family on Plate II., and on page 16. 
