GENERAL EXPLANATION 



OF THE 



PLATES BELONGING TO VOLUME SEVENTH 



OF THE 



EDINBURGH ENCYCLOPEDIA. 



PLATE CCIII. 



Fig. 1. Nautilus Beccarii. Magnified. A spiral Shell, 

 with the cavity divided into chambers. 



a, One of the chambers. 



b, The partition. 



Fig. 2. Helix Paludosa. A spiral Shell, with an un- 

 divided or unilocular cavity. 

 Fig. 3. Orthocera Recta. Magnified. 



a, The outside. 



b, a section, which exhibits the chambers. 

 Fig. 4. Dentalium Gadus. Magnified. An unilocular 



tubular Shell. 



Fig. 5. Odostomia Muscorum. Mag. Spires dextral. 



Fig. 6. Odostomia Laminata. Spires sinistral. 



Fig. 7. Murex Corneus. Divided, in oijler to ex- 

 hibit the pillar round which the spires re- 

 volve. 



a, The pillar. 



b, The mouth. 



c, The canal in which the cavity of the 



mouth terminates. 

 Fig. 8. Planorbis Complanatus. Divided, the spires 



lateral, and destitute of a pillar. 

 Fig. 9. Helix Margarita. 



a, The operculum or lid. 

 Fig. 10. Turbo Elegans. 



a, The operculum rayed. 



Fig. 11. 



Fig. 12, 



Fig. 13. 



Fig. 14. 

 Fig. 15. 

 Fig. 10'. 



Turbo Disjunctus. 

 a, Spires very distinctly separated. 

 Buccinum Reticulatum. 

 a, Outer lip denticulated. 

 Voluta Triplicata. 

 a, The pillar lip plaited. 

 Helix Laevigata. With the epidermis. 

 Epidermis removed. 



Nerita Glaucina. 



a, The pillar cavity. 

 Fig. 17. Nerita Canrena. 



a, The pillar cavity grooved. 

 Fig. 18. Pectuiiculus Pilosus. 



a, The crenulated margin. 



b, The teeth of the hinge. 



c, The ligament. 



d, The beak. 

 Fig. 19- Venus Decussata. 



a, The broad border line approaching tlae 

 • middle of the Shell. 



b, The ligament. 

 cc, The cicatrix. 



Fig. 20. Venus Pullastra. 



a, The fold of the border line, nearer to the 



margin than in Venus Decussate. 



b, The ligament. 



c, The cicatrix. 

 Fig. 21. Solen Marginatum 



