SUBTERRANEAN AJVIPHIPOD STYGONECTES 



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While present patterns of distribution readily correlate with the north- 

 east-southwest linear orientation of valleys and ridges of the central 

 Appalachians, they are not otherwise easily interpreted in terms of 

 ancestral dispersal. Migration of subterranean, ancestral stock 

 into the central Appalachians at a time when this area was reduced 



Figure 31. — Distribution of species of Stygonedes in the central Appalachians. [The 

 emarginatus group: ® S. cooperi; A S. conradi; O S. emargiyiatus; O -S- gracilifes; 

 -\-S. morrisoni; □ S. mundus; X S. stellmacki. The spinatus group: A S. spinaius. 

 Two symbols in a circle indicate two species from the same locality.] 



