74 



MYRIAPODA 



CHAP. 



In the secondary period the Myriapods were scantily repre- 

 sented, or, at any rate, geologists have failed to find their fossils. 

 The class is represented by a single specimen found in the chalk 

 in Greenland. This fossil, which has been included in the 

 Julidae under the name of Julopsis cretacea, may perhaps belong 

 to the Archipolypoda. 



Passing on to the Tertiary or Eecent period, we find the 

 Myriapods again numerous, and more nearly resembling those 

 living at the present time. They belong mostly to the Chilo- 

 gnatha and Chilopoda. They have been found in the fresh-water 

 gypsum of Provence in France, the brown coal of Germany, and 

 the green river formations of America. Several have been found 

 in amber. 



Fossil Myriapods have been divided into four Orders, two 



Fig. 46. Acan- 

 thei'pestes major. 

 (After Zittel. ) 

 Mazon Creek, 

 America, A, 

 The whole 

 animal ; B, 

 branchiae on 

 the ventral sur- 

 face. 



of which coincide with the Orders of living Myriapods ; the 

 difterences between the fossils and the living Myriapods having 

 been held insufficient to warrant the establishment of a new 

 Order. These two Orders are the Chilopoda and the Diplopoda 

 or Chilognatha (Diplopoda is another name used by some writers 

 for the group which we have hitherto called Chilognatha). The 

 other two Orders have sufficient differences from living forms to 

 render it necessary to include them in separate Orders. 

 The fossil Myriapods, then, are arranged as follows : 



Order I. Protosyngnatha. 



Order II. Chilopoda. 



Order III. Archipolypoda. 



Order IV. Chilognatha (or Diplopoda). 



The following table will show the species that have been dis- 

 covered in the different strata : 



