PLATE 83. 



Fig. 1. 708. 19. MuRCHisoNTA bivittata. ( Pag. 345.) 



1 a. A cast of six volutions from tlie central part of the shell. 



1 6. A longitudinal section of several volutions, showing the columella, marked by a double sxjiral fold, and 



the edges of the broken shell. - 



Fig. 2. 709. 20. MaEciiisoNiA longispira. (Pag. 345.) 



2 a. A mould of the middle part of the spire, preserving a portion of the shell and columella near the base. 

 2 6. A fragment showing in the upper part the cast of the interior; the lower part of the specimen preserves 



the shell, which is divided longitudinally. 



Fig. 3. 710. 21. MuRCHisoNiA BOYDii. (Pag. 346.) 



Fig. 4. 711. 22. MuRCHisoNiA LOGANii. (Pag. 346.) 



4 a. A specimen, the upper pan of which is a mould of the shell, while the lower part preserves the cast of 



the interior with some portions of the shell and columella. 

 4 6. A cast preserving several volutions below the apex. 



Fig. 5. 712. 23. Murchisonia macrospira. (P^g- 346.) 



Fig. 6. 713. 24. Murchisonia turritiformis. (Pag. 347.) 



6 a. The cast of two volutions, near the base of the shell. 



6 6. A cast of five volutions, imperfect at both extremities. 



Fig. 7. 714. 2. SuBULiTEs ventricosa. (Pag. 347.) 



7 a. A small specimen having much of the last volution broken oif, but preserving the spire complete. 

 7 6. A large individual with the spire incomplete, but preserving the last volution entire. 



Fig. 8. 722. 7. Calymene . ( Pag. 350.) 



