PLATE II. 



1. a. b. c. d. Nautilus melo, with sections. 



2. Section of Nautilus Jlammatus, shewing the siphon. 



3. Section of Nautilus caudatus, Lister (N. major seu crassus, Rumph.) 



shewing the siphon passing through the chambers. l-4th. 



4. Nautilus Pompilius. 



5. Nautilus auricula. 



6. Scaphites Defrancii. 



6. a. b. c. d. Scaphites wqualis. 



7. 8. Transverse and logitudinal sections of the spine of the Echinus ci- 



daris. 



