T H E T A S M A NIA N N AT U R A LIS' L\ 
25 
Guide to the ffiollusca* 
Adapted for Young Students. 
By W. L. MAY. 
INTRODUCTORY. 
SfJiHE following treatise is very much in the form of a compilation, 
^ being adapted from Woodward with a view to its applicability 
to the Tasmanian fauna. Many genera represented in our waters are not 
mentioned, there being no intention to write a manual, but enough have 
been dealt with to enable the collector to place most of his specimens 
in or near the right place; the accompanying plates will also be of good 
service. To those who are within reach of it, the named collection in 
the Hobart Museum will be found of the greatest assistance. All the 
species likely to be collected by a beginner will be found there repre¬ 
sented. In addition the author will be pleased to assist in identification, 
when the above means have failed. The figures illustrating this paper 
are all drawn from Tasmanian shells. 
The animal kingdom is divided first of all into sub-kingdoms , then 
each sub-kingdom into so many classes containing those which have 
further characteristics in common. The classes into orders , the orders 
into families, the families into genera, and these again into species or 
kinds. 
'1 he Mollusca or solt-bodied animals form a sub-kingdom, and are 
divided into four classes. 
1. Cephalopoda. 
2. Gastropoda. 
3. Pteropoda. 
4 Lamellibranchiata. 
CLASS I. — The Cephalopoda (Head-footed) contains those 
Mollusca that, like the common octopus, have a number of feet (or 
arms) set round the mouth; and is divided into those having two gills 
(Order I. Dibranchiata) and those with four (Order II. Tetrabranchiata). 
Order I. is again divided into (a) Those with eight feet like the 
Argonaut (or Paper nautilus), of which we have one fine species (A 
tuberculala), sometimes drifted on to our coasts; and the common 
octopus (b) those with ten feet, such as the Loligo or squid, whose 
delicate, internal shell so much resembles a pen in shape ; the cuttle 
fish, sepia, whose so-called i bone 1 is frequently found on our beaches, 
and the pretty little spirula (Fig. 6). 
The only representative of the four-gilled order now living is the 
well known Pearly nautilus, but in former times this order was ex¬ 
tremely numerous, especially the Ammonites. 
