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T H E T AS M A NIA N N AT U R A LISE 
13. The Haliotidae , ‘Ear shell ’ or ‘Mutton fish’; we have 
several fine species, one, Haliotis naevasa , being plentiful on rocks at 
about low water mark on many parts of our coast. 
14. The 1 anthinidae or ‘Violet snails’ that float about in the 
open ocean. Two species are occasionally drifted to our shores. At 
certain seasons they secrete a curious float or raft, to which their eggs 
are attached. 
15. Fissurellidae or keyhole and notched limpets (Fig. 17), 
whose name sufficiently describes them, and of which we have several 
interesting species. 
t 6. The Ncreiidae . A group of globular, solid shells (Fig. 12), 
which we have one species common on rocks on parts of the East 
Coast, black on the outer surface and white within. 
17. The Patellidae or True limpets, well known to all seaside 
visitors. Tasmania has some good representatives of the family. 
18. The Dentaliadae , represented by the genus Dentalium or 
‘ Tooth shells,’are simply slightly curved tubes, open at both ends 
and tapering from the mouth downwards, and cannot be mistaken. 
19. Lastly, we have the Chiionidae , whose simple genus Chiton 
(Fig. 16) possess shells differing from all other Mollusca in being 
composed of eight plates overlapping each other and set in a horny 
girdle. This animal is not only like the limpet in form, but also in 
habits, being found adhering to rocks and stones at low water. 
Order II.—Pulmonifera contains the air-breathing Gastropods, 
and to it consequently belong all the terrestrial Mollusca, though some 
few aquatic genera are also included. Foremost in this order stands 
the great family :— 
1. Helicidae , named after its chief representative, the genus Helix 
which is only too well known by the introduced garden snail, 
Helix aspersa. There are a number of interesting, but mostly small, 
species of this lamily in our wooded country, nearly all of which are 
peculiar to the island. 
2. The Limacidae or slugs, also too well known ; some have a 
more,or less imperfect internal shell, others none at all. 
3. The Limnaeidae embrace the ‘ Pond snails’ Limnaea, Physa 
(Fig. 20) (with reversed whorls), Ancylus or freshwater limpet, and 
Planorbis or ‘ Coil shell,’ which is wound like a watch spring. All of 
these have representatives in our rivers and ponds, and we may boast 
of having the finest known Ancylus in the Great Lake. 
4. The Auriculidae includes both spiral shells such as Auricula, 
and a limpet like one, Siphonaria , common on rocky coasts. 
Order III.— Opisthobranchiata. These animals carry their gills 
exposed on their backs and sides, towards the rear of the body ; only a 
few have any shell. 
