PALAEONTOLOGY 75 



Devonian, or 



Old Red Sandstone 



> 2 species of Archipohjpoda. 



CarboniferoiTS . ' ^ "P'^=!'=" Protosyngnatha 



{ 31 species Archipolypoda 



Permian (Rothliegendes of Germany), 4 specimens belonging to the 

 Julidae or Archipolypoda. 



Cretaceous, 1 species 



f Archipohjpoda or 

 I Chilognatha 



(11 species Ghilopoda 



Oligocene ^3 species / ^nM^'"^«' 



[, \ {Clnlognathd) 



,,. -, . f Diplopoda 



Miocene, . 1 species < ,„, ./ „ , 

 [ {Uhiiogncma) 



I will now give a short account of the different Orders, and 

 the fossil forms which are included in them. 



Order I. Protosyngnatha. 



This Order is represented by a single fossil (Fig. 45), dis- 

 covered in the coal at Mazon Creek, Illinois, America, by Meek 

 and Worth. It differs greatly from any of those in existence at 

 the present day. The body is cylindrical, and composed of 

 ten segments. The cephalic appendages (that is, the antennae 

 and mouth parts) are inserted into a single unsegmented cephalic 

 mass (the head). Each segment behind the head bears a single 

 dorsal and ventral plate of equal breadtli and length. The 

 limbs are placed in these plates with a wide space between the 

 base of each leg and that of the opposite one of the pair. Along 

 the back, bundles of bristles are arranged in longitudinal rows. 



Order II. Ghilopoda. 



The fossil forms of this Order resemble those of the Ghilopoda 

 of the present day. The oldest of them are found in amber. 

 The following families have been found : — ■ 



Lithohiidae. Several species have been found in amber. 



Scolopendridae. One species in amber, several species in 

 later Tertiary formations. 



Geoph.ilidae. Three species in amber. 



Two species resembling the Schizotarsia of the present day 

 have been found in amber. 



