584 ARTHROPODA. 



furnished outside the legs with large stigmata directed transversely 

 to the axis of the body (Scudder). This order comprises all the 

 Palaeozoic Myriopoda with the exception of the Carboniferous genus 

 Palceocampa, and it is not known to have any representatives in 

 the Mesozoic or Kainozoic rocks. The most ancient types of the 

 Archipolypoda at present known are those recorded by Page and Peach 

 as occurring in the Old Red Sandstone of Scotland (Kampecaris and 

 Archidesmus). With these exceptions, all the members of the order 

 are either Carboniferous or Permian in age. The three most im- 

 portant genera of the Archipolypoda are Euphoberia, Archiulus, and 

 Xylobius. In the genus Euphoberia (rig. 439) the dorsal shields 

 are divided each into two more or less closely consolidated, but dis- 

 tinctly separate sub-segments, one of which is much more elevated 

 than the other. The segments are generally from two to three 

 times broader than long, and they carry subdorsal and lateral rows 

 of large spines, which are forked and terminate in simple ends. 

 The species of Euphoberia are found in the Coal-measures of North 



Fig. 439. — Portion of the body of Euphoberia armigera, from the Coal-measures of Illinois, 

 of the natural size (after Meek and Worthen). The dark spots on the dorsal shields are pits left 

 by the breaking off of the dorsal spines. 



America and Britain. The genus Acantherpestes includes Carbon- 

 iferous Myriopods which differ from Euphoberia chiefly in having 

 the spines bifurcated at the tip, though there are other characters 

 of difference as well. Acantherpestes major, of the Coal-measures 

 of Illinois, attained a length of about a foot, and " was armed with 

 coarse branching spines more than a centimetre long " (Scudder). 

 Mr Scudder regards this species as having been amphibious in 

 habit, as he considers that certain lateral openings which it exhibits 

 were branchial in character. 



The genera Archiuhis and Xylobius constitute a special family 

 (Archiulidce) of the Archipolypoda, characterised by the fact that the 

 dorsal plates are " closely consolidated, but still distinctly separable," 

 though the anterior is rarely much elevated above the posterior 

 sub-segment. The body is "almost smooth or covered more or 

 less abundantly with serially disposed papillae, from which in some 

 cases hairs or small spines arise" (Scudder). These genera are 

 closely allied in some respects to the Millepedes (Diplopodd), though 

 they would seem on the whole to be properly referable to a 



