» • 822 [Assemble 
the animals under consideration pertain to the order Isopoda, i. e. 
equal footed, having fourteen pairs of legs of nearly equal size, 
and to the family Ontscid.®, which, like other families of this 
order has four antennse, but here the inner pair of these antennae 
is quite short and little apparent, consisting at most of only two 
Joints. The typical genus of this family, named Oniscus by Lin¬ 
naeus, is by modern naturalists restricted to those species in which 
the external antennae have eight joints, the three last joints being 
much more slender than the others, and the sutures separating 
them much less distinct than those between the other joints. I 
have never met with any American species having this number of 
joints to the antennae. The genera Porcellio and Armadillo differ 
from Oniscus in having the slender terminal portion of the an¬ 
tennae divided into but two joints instead of three, making the 
number of joints seven in all. 
The genus Armadillo is distinguished from Porcellio , and from 
Oniscus also, by being destitute of the two conical projecting 
points or short tail-like processes which we observe at the tip of 
the abdomen in those genera, and also by having the faculty of 
rolling i.tself into a ball, resembling when thus rolled up a pea or 
pill, whence they are popularly named pill-millipedes. We have 
one or more species of these inhabiting the southern part of the 
State and Long Island, but they do not extend to the neighbor¬ 
hood of my residence, and I have not examined them sufficiently 
to determine whether they are different from the European species 
of this genus. 
All the animals of this family which have yet been discovered 
in the central and northern sections of our State pertain to the 
genus Porcellio. These crustaceans are everywhere common 
about the roots of trees, under logs and stones, in the crevices of 
the foundation walls of our buildings and in our cellars, and they 
are particularly numerous under any logs or billets of wood 
which are left in our chip yards. They occur, in short, in all 
situations that are damp, cool and dark. Frequently, by night 
in wet weather, they crawl about the rooms in our dwellings. 
They are perfectly innocent and harmless, subsisting upon decay- 
