THE TASMANIAN NATURALIST 
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ties for its occurrence being the top of Mount Wellington, the Hartz 
Mountains, and Mount Field. A figure of the animal’s appearance is 
given here. 
The two pronged or 
biramous character of the 
limbs is especially to be 
noted, as this is character¬ 
istic of the young stages 
in growth of almost all 
Crustacea, and its being 
retained here in the adult 
is another primitive or 
ancestral feature. Another 
character of the mountain 
shrimp is that instead of 
the female carrying about 
her eggs with her as in all 
other Crustacea, she hides 
them under stones and in 
the roots of water plants. 
We have so far only spoken of the higher Crustacea in which the 
body is always composed of twenty segments. These are called 
Malacostraca. 1 here are besides a host of small Crustacea in which the 
body is not composed of any constant number of segments but may be 
less or more than twenty according to the species under consideration. 
These Crustacea are classed together as Entomostraca. 
Probably the most familiar of these are the Barnacles, the little 
sharp shells attached to rocks at tide marks. Each of these little boxes 
really contains a live Crustacean, which, when he is covered with water, 
pokes out his legs and sweeps particles of food into his mouth. 
Besides the Barnacles or Cirripeds there is a great number of small 
Crustacea which swarm on the surface of the sea, and afford a very 
important article ol food to the shoals of fishes and even to whales. 
lhe.se little Crustacea, each single one of which is not bigger than a 
pin’s head, are often present in such enormous quantities that the sea 
may be coloured red with them and have the consistency of chocolate. 
Some ol these marine forms are highly phosphorescent and may 
give rise to the phosphorescent seas so much admired by travellers. 
But besides swarming in the sea, there is often a great developement 
ol these creatures in fresh water lakes, and by drawing a tow net of silk 
gauze, with a bottle attached to the end of it, through the water, 1 have 
succeeded in collecting several kinds of Entomostraca in great numbers, 
both in the Hartz Lakes and in the Great Lake and Lake St. Clair! 
1 he water in the last named lake, being extremely deep and clear 
afforded the richest variety of this perpetually floating life. On a bright 
sunny day :t is necessary to sink the net to a considerable depth in the lake, 
since these creatures cannot bear the direct rays of the sun upon them. 
