MILLIPEDES AND SCORPIONS. 
213 
together. The pill-millipede ( Glomeris ) is said to encase only a few eggs in a ball of 
earth; while lulus lays from sixty to a hundred in her nest before closing the 
aperture. Among the suctorial millipedes it is said that the common European 
Polyzonium germanicum coils round her cluster of eggs and stays by them 
until they are hatched. When 
hatched, the young are minute, pale- 
coloured creatures, consisting of the 
head, with its antennae and jaws, and 
six bod}' segments, of which the first 
three are provided with a pair of legs 
apiece. During growth the rest of 
the segments are gradually added 
between the fifth and sixth, the latter 
remaining the terminal segment. 
Growth is also accompanied by 
moulting. 
Remains of extinct millipedes, 
referable to several of the existing 
families, occur in the middle Tertiary 
rocks, while one species of doubtful 
position has been discovered in the 
Cretaceous. In the Carboniferous and 
Devonian rocks a number of types 
apparently referable to the millipedes occur, although they have been assigned to 
a special order. From the existing forms they differ by the incompleteness of 
the union between the dorsal elements of each double segment. 
Allied to the millipedes in many characters, but differing in certain special 
features, is the small group known as Pauropoda. These contain some minute 
creatures, found in earth and rubbish heaps in Europe and North America, and 
remarkable for the fact that their antennse are branched at the apex, and furnished 
with long bristles. These have twelve body segments, and only nine pairs of legs, 
the first and the last two segments being limbless. 
Scorpions, Spiders, Ticks, etc,— Class Arachnida. 
The members of the three classes of Arthropods hitherto considered are 
characterised by the possession of a distinct head, bearing in front of the mouth a 
pair of antennae, and at the sides of the same at least two pairs of appendages, 
which act solely as jaws. In the scorpions, spiders, and their allies, on the other 
hand, there is no such distinct head, while antennse are wanting; the first pair of 
appendages being composed of two or three segments only, and acting as seizing 
or biting organs. These mandibles are, in fact, the only limbs that can be 
described as jaws. It is true that the basal segments of the second, and sometimes 
of the third and fourth, pairs of limbs are used for crushing prey; but their 
remaining segments nearly always form leg-like appendages, used both for locomo¬ 
tion and grasping. In scorpions, for instance, the limbs of the second pair are 
millipede OP the genus Spirostreptvs, from Celebes. 
