6 
THE T ASM A NI AN NATU R AI A ST 
have crossed : so that the present distribution of these lobsters informs 
us pretty certainly that at some rather remote period there must have 
been a continent somewhere in the antarctic seas connecting the 
southernmost parts of South America, New Zealand, Australia, and 
Madagascar together, and in this region the ancestors of all these 
southern lobsters must have lived. 
The so-called land-crab of Tasmania which tives in deep burrows 
upon marshy plains in the mountains, especially near the west coast, is 
really a lobster, too, closely related to the Astacopsis ; its scientific 
name is Engaeus fossor. Curiously enough, some of the North 
American lobsters of the genus Cambarus have also taken to making 
burrows in the earth, and have quite forsaken their natural element of 
water. 
The Crustacea we have hitherto mentioned, namely, shrimps, 
lobsters, crayfish, and crabs, although they differ from one another in 
many points, are really all built upon the same plan, and are made up of 
the same number of segments. If you look at a lobster or shrimp you 
will see that its hinder end or tail is composed of a number of rings or 
segments, to each of which is attached a pair of jointed limbs. The 
front part of the body or cephalothorax (/>., head-chest) does not 
show clearly this structure of ringing or segmentation, but the limbs 
attached to this part of the body indicate the number of segments out 
of which it is constructed. 
Now in all the above-mentioned Crustacea there are 20 seg¬ 
ments with their limbs, two pairs of feelers or atennse; three pairs 
of jaws, which are used for biting the food, but are really modified 
limbs ; three pairs of auxiliary jaws or maxillipeds, which are half jaws 
and half legs ; five pairs of walking legs, some of which end in pincers ; 
and then follows the seven tail segments or rings, which carry seven pairs 
of swimming legs. 
As before stated, the first thirteen segments of the body are all 
fused together to form a carapace or shell, so that there is no outward 
sign of segmentation except the limbs, and the front ones of these are so 
much drawn into the mouth to act as jaws that one can hardly believe 
that they correspond to limbs attached to regular segments as in the tail 
region. 
Now it is the unique distinction of Tasmania (or was until the other 
day when a similar discovery was made in Victoria), to possess a very 
peculiar shrimp-like animal in which the body is segmented or ringed all 
the way down, and in which the limbs preserve their simple character of 
double-pronged oars right up into the region of the mouth. 
It is clear that this animal (Anaspides Tasmania, Thomson) 
preserves the simple primitive plan — the diagrammatic form as it were— 
upon which the higher Crustacea are built, and everything we can learn 
about its structure and habits is of great interest. It appears to live 
only in mountain streams and clear tarns at a great elevation, the locali- 
