SCORPIONS, SPIDERS, TICKS, ETC. 



3179 



crushed fragments of a large Spirostreptus. Many of the species which have no 

 glands are otherwise protected. Polyxenus, for instance, is studded with bristles; 

 while the Oniscomorpha roll themselves up into a round ball, with nothing but the 

 horny integuments exposed. In the breeding season the females of several forms 

 make earthen nests for their eggs, working the lumps together. The pill millipede 

 (Glomeris) is said to incase 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- 

 colored 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 

 molting. 



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 



MILLIPEDE OF THE GENUS Spirostreptus. 



(From Celebes.) 



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 characteristics, 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 re- 

 markable 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. 



SCORPIONS, SPIDERS, TICKS, ETC. Class Arachnida 



The members of the three classes of Arthropods hitherto considered are 

 characterized by the possession of a distinct head, bearing in front of the mouth a 

 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 



