rALAEONTOLOGY 



73 



had appeared on the earth. The Myriapods of the Old Eed 

 Sandstone, as has heen before said, differ considerably from those 

 of the present day, and as we proceed towards the species found 

 in the more recent strata we find them more and more like the 

 ones at present living, till we get to the Polyxenus and other 

 species found in amber, which are hardly to be distinguished 

 from living forms. 



The next oldest fossil Myriapods are found in the coal 

 measures, when both the animal and vegetable kingdoms were 

 represented by more numerous and more specialised forms. The 

 fossil fauna of this period is characterised by the number of 

 gigantic Amphibia, many remains of which have been found. 

 The great forests and the abundant vegetation of this time must 

 have been favourable to the existence of our class, and accord- 

 ingly we find no less than 32 species of fossil Myriapods. Of 



Fig. 45. — Palaeocmivpa an- 

 thrax. (After Meek and 

 Worth.) From Mazon 

 Creek, Illinois. 



these most have been found in America, some in Great Britain, 

 and some in Germany. One well-preserved fossil of Xylohius 

 sigillariae was found by Dr. Dawson in America in the stump of 

 a tree in the remains of a fossil forest. The eyes, head, and 

 legs were plainly seen under the microscope. All these fossils 

 belong to the earliest or Palaeozoic period. 



The fio-ure below (Fig. 46) shows a fossil also from the coal 

 formations of Illinois, America, belonging to the family of the 

 Euphoberiidae mentioned further on. It shows a nearer approach 

 to the Julidae of the present time. The limbs, however, were of 

 very curious shape, and may possibly have been adapted to loco- 

 motion in water as well as on land, and the small supposed 

 branchiae on the ventral surface shown in Fig. 46, B, may possibly 

 have been an arrangement to render respiration in the water 



possible. 



