MILLIPEDES AND SCORPIONS. 



213 



together. The pill-millipecle (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 body 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 antennae 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. 



MILLIPEDE OF THE GENUS Spirostreptus, from Celebes. 



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 antennae 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 



