104 GUIDE TO THE EOSSIL INVEETEBEATE ANIMALS. 



Gallery 

 VIII. 



Table-case 



20. 

 Wall-ease 



12c. 



jaw-limbs, the mandibles and the maxillae, the latter joining 

 to form a lower lip. 



Millipedes of modern character are found in Tertiary 



rocks, especially in 

 amber, e.g. Juhts and 

 Polyxemis. The Me- 

 sozoic rocks furnish 

 a single doubtful 

 form, Jvlopsis, of 

 Cretaceous age, and 

 a few from tlie Trias. 

 The Palaeozoic forms 

 above referred to 

 occur in the Devo- 

 nian and Carboni- 

 ferous rocks. In the 

 British series are ex- 

 hibited Eii2)hoheria 



Fig. 51. — A fossil Millipede, Eupkoheria ferox, 

 Coal Measures, Coalbrookdale, Shropshire. 

 Natural size. 



(Fig. 51) and Xylohius from the Coal Measures. 



Class CHILOPODA (Centipedes). 



Superficially like the millipedes, the centipedes differ in 

 never bearing more than one pair of legs on a body-segment, 

 and in having four pairs of jaw-limbs. The stigmata lie in 

 the membrane between the horny rings of the segments. 

 These also being dwellers on land, are not common as 

 fossils, and up to the present are not represented in the 

 Museum. 



Class INSECTA. 



Table-case The insects are the most highly modified of Arthropoda. 



Wall-ease centipedes they breathe by tracheae and have a long 



12b. segmented body ; but in addition to a distinct head, the 

 hinder part of the body is sharply divided into a thorax of 

 three segments in front and an abdomen of nine or ten 

 segments behind, and it is only the thorax that retains legs, 

 these being always in three pairs. The head bears a pair 

 of compound eyes, a pair of antennae, and three pairs of 

 jaw-limbs. Most insects have on the thorax two pairs of 

 wings. 



Owing to certain difficulties attending the study of fossil 



