No. 3668 PTERODRILUS—HOLT 29 
taken in Whetstone Creek on U.S. Highway 60, 5 miles west of Moun- 
tain Grove, Wright County, Mo., by Perry C. Holt, August 23, 1961. 
Draenosis.—Low dorsal ridges on segments I-VII, higher one on 
VIII, no dorsal projections; bursa large, its length equalling or ex- 
Ficure 8.—Pterodrilus missouriensis: a, lateral view of reproductive systems; b, holotype. 
