es
short, stout, tapering, the segments about as wide as long, except the
apical, which is distally slender, pointed, slightly curved, and
without distinct movable claws.

Family--Palaeophonidae, _Palaeophonus_ (figs. 48 and 49).

Sub-order Dionychopoda.--The 3rd, 4th, 5th and 6th pairs of appendages
slender, not evenly tapering, the segments longer than wide; the
apical segment short, distally truncate, and provided with a pair of
movable claws. Basal segments of the 5th and 6th pairs of appendages
abutting against the sternum of the prosoma (see fig. 10 and figs. 51,
52 and 53).

Family--Pandinidae (_Pandinus, Opisthophthalmus, Urodacus_).
" Vejovidae (_Vaejovis, Jurus, Euscorpius, Broteas_).
" Bothriuridae (_Bothriurus, Cercophonius_).
" Buthidae (_Buthus, Centrums_).
" *Cyclophthalmidae (_Cydophthalmus_) ( Carboniferous.
" *Eoscorpiidae (_Eoscorpius, Centromachus_) (

[Illustration: FIG. 49.--Ventral view of a restoration of
_Palaeophonus Hunteri_, Pocock, the Silurian scorpion from Lesmahagow,
Scotland. Restored by R.I. Pocock. The meeting of the coxae of all the
prosomatic limbs in front of the pentagonal sternum; the space for a
genital operculum; the pair of pectens, and the absence of any
evidence of pulmonary stigmata are noticeable in this specimen.

(See Pocock, _Quart Jour. Micr. Sci._, 1901.)]

_Remarks on the Order Scorpiones._--The Scorpion is one of the great
animals of ancient lore and tradition. It and the crab are the only
two invertebrates which had impressed the minds of early men
sufficiently to be raised to the dignity of astronomical
representation. It is all the more remarkable that the scorpion proves
to be the oldest animal form of high elaboration which has persisted
to the present day. In the Upper Silurian two specimens of a scorpion
have been found (figs. 48, 49), one in Gothland and one in Scotland,
which would be recognized at once as true scorpions by a child or a
savage. The Silurian scorpion _Palaeophonus_, differs, so far as
obvious points are concerned, from a modern scorpion only in the
thickness of its legs and in their terminating in strong spike-like
joints, instead of being slight and provided with a pair of terminal
claws. The legs of the modern scorpion (fig. 10; fig. 51) are those of
a terrestrial Arthropod, such as a beetle; whilst those of the
Silur