Plate XVIII.

• Fig. 10. a, b. Amphidoxa feredayi, mihi.

• " Q. " " jaw.

• " R. " " teeth, X 480.

• Fig. 11. a, b.Phrixgnathus acanthinulopsis, mihi.

• " S. " " part of jaw.

• " T. " " teeth, X 480.

• Fig. 12. a, b, c. Amphipeplea ampulla, Hutt., v. globosa, mihi.

• Fig. 13. a, b, c. Potamopyrgus corolla, Gould. One day old.