. . .Miocene (of Oenigen and Baden), and occur also in amber (79); while examples of genera, such as Oniscus and Porcellio, have been discovered in late Tertiary deposits (47).

External structure and appendages.—Woodlice agree in being of a somewhat oval form, and their bodies are arched, the curve varying in different genera and species. A head is to be distinguished; behind this comes the thorax of seven segments which are often considerably broader than the six succeeding ones which form the abdomen (see fig. 1.)

The head carries two large antennae (fig. 3) which are very evident, and a careful search with a lens will reveal a second and minute pair (the smaller antennae) situated between the base of the others, and really anterior to them. (figs. 2 and 4.)

The larger antennae are customarily bent at certain points, and we can distinguish a[Pg 3] terminal part, or flagellum, and a basal part, the peduncle (fig. 3). The number of joints . . . Read More