488 ONISCIDA. 
Kinahan, having been confounded with P. scaber, trom 
which, however, it is at once distinguished by its more 
elongate form, less rugose surface, and especially by the 
narrowness of the tail, in which respect it approaches 
the species of the genus Philoscia. ‘The posterior angles 
of the three anterior joints of the body are obtuse, and 
those of the following joints are much less acutely pro- 
duced backwards than in most of the other species of 
the genus. ‘The lobes of the head are but slightly pro- 
duced, the central one being small and rounded. The 
tail is small, the three principal segments being com- 
paratively minute, as compared to their size, in the 
preceding species. The terminal joint is short and 
triangular, its extremity only extending a little beyond 
the base of the terminal division of the apical appen- 
dages of the tail, which is considerably elongated, as are 
also the legs; the whole structure of the animal indi- 
cating greater activity and powers of movement. 
The variety P. maculicornis of Koch is of an iron 
colour, with the outer antenne ringed with white, the 
segments of the body having the posterior margins 
simply granulated, and the terminal appendages of the 
tail of a ferruginous colour, 
The species is of an uniform mouse-grey colour, seen 
under a lens to be marked with white. It generally con- 
ceals itself rapidly from the light, but, when disturbed, 
runs with great rapidity. It prefers moderately humid 
warm situations, and occasionally buries itself in the 
earth, even in clayey localities, to a considerable depth. 
It is very common both in England and Ireland. The 
neighbourhoods of Dublin and Chiselhurst, Kent, are 
localities in which they are found. It is equally plen- 
tiful in the vicinity of Oxford. 
