20. (1) Skull of Erpetosaurus minutus Moodie, from the Cannelton slates of Pennsylvania 154 (2) Skull and anterior part of body of Ptyonius pectinatus Cope, from the Coal Measures of Linton 134 (3) Skeleton of Eosauravus copei Williston, from the Coal Measures of Linton. "The oldest known reptile from North America" and closely related structurally to the Microsauria 134 (4) Part of ventral scutellation and ribs of Sauropleura digitata Cope, from the Coal Measures of Linton 134 21. (1) Mandible of Macrerpeton deani Moodie, from the Linton Coal Measures 136 (2) Portion of the skull of Macrerpeton deani Moodie, possibly of the same: individual us the mandible. From the Linton Coal Measures 136 (3) Type of Cercariomorphus parvisquamis Cope, from the Linton Coal Measures 136 (4) An additional specimen of Cercariomorphus parvisquamis Cope, from the Linton Coal Measures 136 (5) Skull of Sauropleura scutellata Newberry. From the Coal Measures of Ohio 136 (6) Tooth of Mastodonsaurus sp. indet. of the Carboniferous of Kansas 136 (7) Tooth of Mastodonsaurus giganteus Jaeger, from the Triassic of Germany. Introduced for comparison with the tooth from the Kansas Carboniferous 136