8 Jr 
THE FERN FORESTS )F 
ing, but even the hollow trunks of the trees 
themselves. 
Let us give a glance now at the animals which 
inhabited the waters of this period. In the Ra- 
diates we shall not find great changes ; the three 
classes are continued, though with new represen- 
tatives, and the Polyp Corals are increasing, while 
the Acalephian Corals, the Rugosa and Tabulata, 
are diminishing. The Crinoids were still the 
most prominent representatives of the class of 
Ecliinoderms, though some resembling the Oplii- 
urans and Ecliinoids (Sea-Urchins) began to 
make their appearance. The adjoining wood-cut 
represents a characteristic Crinoid of the Carbon- 
iferous age. 
Among the Mollusks, Bra- 
cliiopods are still prominent, 
one new genus among them, the 
Productus, being very remark- 
able on account of the manner 
in which one valve rises above 
the other. The following wood- 
cut represents such a shell, 
looked at from the side of the 
flat valve, showing the straight 
cut of the line of juncture be- 
tween the valves and the rising 
curve of the opposite one, 
which looks like a hooked beak when seen in 
profile. 
