528 Transactions. | 
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to 3mm. in diameter. Adult shells of Melaraphe and Risellopsis ате not 
found in this association, but occur at higher levels Two crustacea are 
found among Bostrychia—a small Sphaeroma and a small orchestid. (Plate 46, 
fig. 1.) 
- Caulacanthus Association. (Plate 43, fig. 1.) 
associations. Caulacanthus occurs in irregular patches 2-3 cm. to 50cm. 
in diameter and 10-15 mm. high. It is reddish-olive, but in bright suulight 
shows a light olive colour. Its dense mats keep moist between tides, and 
harbour a quantity of mud. In places it is mixed with the pelecypod 
Modiolus pulex. On its surface are found many Onchidella and a few 
Lepsiella scobina ; but underneath is a much greater variety of life—Nereis 
.. The Caulacanthus association does not form a continuous covering in 
the belt in which it occurs. The greater portion of the rock-surface 1s 
occupied by a nearly uniform covering of small Elminius modestus, with 
which are associated Elminius plicatus, Chamaesipho columna, Sypharo- 
chiton pellisserpentis, and’ various gasteropods— Lepsiella scobina, Nerita 
melanotragus, Monodonta aethiops, Siphonaria zealandica, Risellopsis varia, 
and Turbo smaragdus. 
CORIACEOUS-COATED-ANIMALS FORMATION. 
Cynthia Association. ea 
Auckland Harbour.—A long reef of volcanic rocks stretches from west pee 
of Ponsonby towards Kauri Point, fairly across the tidal currents. Rivers — 
flowing into the upper reaches of the harbour bring down much mud and _ 
decayed vegetable matter, a great deal of this being caught by the reef, 
which, except where exposed to the scouring action of waves an tides, 
ars а coating of slimy mud. It is not to be wondered at, therefore, 
animal associations rich in individuals and species are found near 
