ATOPETHOLID MILLIPEDS — HOFFMAN AND ORCUTT 



121 



following frequency distribution: 46 segments in 2 specimens, 47 in 

 2, 48 in 5, and 49 in 3. The statistical mean for this series is 47.7, with 

 a standard deviation of 1.06. Although the series is not large, a spread 

 of 6 standard deviations should include about 99 percent of the total 

 variability to be expected for an unlimited series from the locahty 

 sampled. Numerically this yields an expected^ range in segment 

 number of 44 to 51, actually not much greater than the observed 

 range in the material studied. 



Figure 4. — Eurelus soliatus Cook, male specimen from Webb County, Texas: a, anterior 

 gonopods, cephalic aspect; b, anterior and left posterior gonopods, caudal aspect; c, right 

 posterior gonopod, cephalic aspect, enlarged; d, 3rd leg; e, 4th leg;/, 6th leg. 



