Plate 18. 



Fig. 1. Mdi-ftiprlhi ylyunt((i. X 15. Front view. 



2. Marsipella gigantea. X 15. Apertural vimv. 



3. Keophn.r horri'/us. X 30. Front view. 



4. Keophn.r liorri'lus. X 30. Ap?rtural view. 



5. Ilaliphjjsema catcnidata. X 15. Front view. 



(5. Haliphysema catenulata. X 15. Ajjertural vi?w. 



7. Dcm/rophri/a ramosa. X 15. F'ront view. 



8. D(ndrophri/a ramosa. X 15. Apertural view. 



9. Ilonnosinn ovali/ormis. X 15. Front view. 



10. Hormosbui oralifonnis. X 15. Apertural view. 



11. AmmosphdrrnHna ndhaerens. X 30. Interior view. 



12. Arnmospliafntlina adhaerens. X 30. Exterior view 



507 



